Structure and diversity of ground mesofauna inUlmus and Populus consortia in the industrial areas of mining and smelting complex of krivyi rig basin

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V. V. Kachinskaya

2010-05-01

Full Text Available The structure and biological diversity of ground mesofauna on a consortium level of organisation of ecosystems are considered. Indicators of structural organisation and biodiversity of ground mesofauna were analised in Ulmus and Populus consortia in the conditions of industrial territories of mining and smelting complex of Krivyi Rig Basin. It is established that taxonomical structure of ground mesofauna is characterised by insignificant number and quantity of taxonomical groups. Prevalence of hortobionts and herpetobionts in morpho-ecological structure of the community testifies to their attachment to consortium’s determinants and influence of steppe climate on its structure. Dominance of phytophages and polyphages in trophic structure is caused by a combination of consortium determinants specificity and «a zone source» of the fauna formations. The structural organisation of ground mesofauna in consortia of Ulmus and Populus in the conditions of industrial sites is characterised by simplified taxonomical structure with low biodiversity at all levels.

Collembolan trait patterns with climate modifications along a European gradient: the VULCAN case study

DEFF Research Database (Denmark)

Bonfanti, Jonathan; Cortet, Jérôme; Hedde, Mickaël

In a climate change context, soil ecosystem services can be threatened, notably through impacts on soil fauna. Collembola can be therefore used for bioindication of soil mesofauna functionality. Here we aim (i) to link distribution of the collembolan communities with their functional traits...

Missing links in the root-soil organic matter continuum

Energy Technology Data Exchange (ETDEWEB)

O' Brien, Sarah L. [Argonne National Laboratory (ANL); Iversen, Colleen M [ORNL

2009-01-01

The soil environment remains one of the most complex and poorly understood research frontiers in ecology. Soil organic matter (SOM), which spans a continuum from fresh detritus to highly processed, mineral-associated organic matter, is the foundation of sustainable terrestrial ecosystems. Heterogeneous SOM pools are fueled by inputs from living and dead plants, driven by the activity of micro- and mesofauna, and are shaped by a multitude of abiotic factors. The specialization required to measure unseen processes that occur on a wide range of spatial and temporal scales has led to the partitioning of soil ecology research across several disciplines. In the organized oral session 'Missing links in the root-soil organic matter continuum' at the annual Ecological Society of America meeting in Albuquerque, NM, USA, we joined the call for greater communication and collaboration among ecologists who work at the root-soil interface (e.g. Coleman, 2008). Our goal was to bridge the gap between scientific disciplines and to synthesize disconnected pieces of knowledge from root-centric and soil-centric studies into an integrated understanding of belowground ecosystem processes. We focused this report around three compelling themes that arose from the session: (1) the influence of the rhizosphere on SOM cycling, (2) the role of soil heterotrophs in driving the transformation of root detritus to SOM, and (3) the controlling influence of the soil environment on SOM dynamics. We conclude with a discussion of new approaches for gathering data to bridge gaps in the root-SOM continuum and to inform the next generation of ecosystem models. Although leaf litter has often been considered to be the main source of organic inputs to soil, Ann Russell synthesized a convincing body of work demonstrating that roots, rather than surface residues, control the accumulation of SOM in a variety of ecosystems. Living roots, which are chemically diverse and highly dynamic, also influence a

Impact of set-aside management on soil mesofauna

Science.gov (United States)

Landi, Silvia; d'Errico, Giada; Mazza, Giuseppe; Mocali, Stefano; Bazzoffi, Paolo; Roversi, Pio Federico

2014-05-01

To contrast the biodiversity decline, the current Common Agricultural Policy (CAP) 2014-2020 responds to urgent environmental challenges and provides some new greening attempts as pastures, rotations, orchard grasses, ecological set-aside and organic farming. This study, supported by the Italian National Project MONACO (MIPAAF), aims to provide preliminary indications about the ecological impact of set-aside on soil biodiversity. Soil invertebrates, mainly nematodes and microarthropods, are excellent candidates to study the human activity impacts on the environment. Indeed, invertebrates are abundant, relatively easy to sample, and they can quickly respond to soil disturbance. Nematode assemblages offer several advantages for assessing the quality of terrestrial ecosystems because of their permeable cuticle through which they are in direct contact with solvents in the soil capillary water. Moreover, nematodes have high diversity and represent a trophically heterogeneous group. The Maturity Index (MI), based on the nematode fauna, represents a gauge of the conditions of the soil ecosystem. Edaphic microarthropods play an important role in the soil system in organic matter degradation and nutrient cycling. They show morphological characters that reveal adaptation to soil environments, such as reduction or loss of pigmentation and visual apparatus, streamlined body form with appendages reduction, reduction or loss of flying, jumping or running adaptations, thinner cuticle for reduced water-retention capacity. The "Qualità Biologica del Suolo" (QBS) index, namely "Biological Quality of Soil", is based on the types of edaphic microarthropods to assess soil biological quality. Three different set-aside managements were compared with a conventional annual crop in three Italian sites (Caorle, VE; Fagna, FI; Metaponto, MT). After five years the biological quality of soils using MI and QBS was evaluated. Regarding nematodes, the family richness and the biological quality

Communities of microorganisms and invertebrates in soil-like bodies of soccer fields in Moscow oblast

Science.gov (United States)

Kutovaya, O. V.; Zamotaev, I. V.; Belobrov, V. P.

2014-11-01

Artificially created soil-like technogenic formations (STFs) of soccer fields are developed under combined action of intense technogenic and natural factors and processes, which cannot but affect the structure and biological activity of their microbial communities and mesofauna. The microflora of the STFs is very similar to the microflora of the background soddy-podzolic soils of Moscow oblast with respect to the composition of the physiological groups of microorganisms. However, they are drastically different in their quantitative characteristics. The numbers of all the trophic groups of microorganisms, except for the microscopic fungi, in the STFs are much higher than those in the zonal soils. An increased biological activity of the STFs is due to regular watering, heating, application of sand and mineral fertilizers, and technogenic turbation processes. The mesofauna of the STFs is represented by several ecological groups of earthworms, including soildwelling (endogeic) earthworms ( Aporrectodea caliginosa), epigeic earthworms dwelling at the soil-litter interface ( Lumbricus rubellus), and litter-dwelling earthworms ( Eisenia foetida).

Mesofauna edáfica: indicador biológico de la calidad del suelo

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Ana Socarrás

Full Text Available La búsqueda, el uso y la aplicación de los indicadores de la calidad del suelo se han intensificado en las últimas décadas, debido a la necesidad de preservar este recurso no renovable e indispensable para la vida humana, ante el deterioro creciente. La selección de los indicadores se ha dirigido, fundamentalmente, a conocer el efecto de los usos aplicados y el curso de la rehabilitación de los suelos degradados o contaminados. Los grupos que integran la mesofauna edáfica son sensibles a las perturbaciones naturales y antrópicas del medio, las que provocan cambios en su composición específica y su abundancia, y ocasionan la pérdida de especies y de su diversidad, con la consiguiente disminución de la estabilidad y la fertilidad del suelo. Por ello la mesofauna edáfica es considerada como un buen indicador biológico de su estado de conservación. El número, la densidad y el balance de sus grupos permiten predecir y evaluar las transformaciones ocasionadas por la aplicación de diferentes métodos de producción agrícola en condiciones edafoclimáticas específicas, así como considerar integralmente el funcionamiento del ecosistema.

Influence of moisture conditions and mineralization of soil solution on structure of litter macrofauna of the deciduous forests of Ukraine steppe zone

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V. V. Brygadyrenko

2015-02-01

Full Text Available The accounting of litter mesofauna was carried out in the territory of Dnipropetrovsk, Zaporizhzhya, Nikolaev,Donetsk regions of Ukrainein the natural forest ecosystems in 2001–2014. 339 forest ecosystems were surveyed; xeromesophilic conditions of moistening were characteristic for 47 trial sites, mesophilic conditions – for 99 sites, hygro-mesophilic conditions – for 50 sites, meso-hygrophilic conditions – for 89 sites, hygrophilic conditions – for 54 sites; trophotope C was represented by 35 trial sites, Dc – by 44, Dac – by 76, Dn – by 128, De – by 37, E – by 19 forest ecosystems, accordingly. The relative number of saprophages reaches maximum values in hygro-mesophilic, meso-hygrophilic and hygrophilic conditions, and minimum values – in mesophilic conditions of moistening. The share of rare species is maximum in hygro-mesophilic conditions of moistening. The minimum quantity of mass species is also observed in conditions of hygro-mesophilic and meso-hygrophilic deciduous forests. With the growth of moistening of the soil, quantity of species of Carabidae, Formicidae and other dominant families remains without significant changes. The relative number of Formicidae is maximum in xeromesophilic and mesophilic conditions of soil moistening. In these hygrotopes, as well as in hygro-mesophilic conditions of moistening the Julidae numbers are maximum. The Isopoda percent in mesofauna significantly grows in meso-hygrophilic and hygrophilic conditions of moistening. The share of other dominant taxonomical groups in the structure of litter mesofauna remains without significant changes in numbers. In the majority of the analysed hygrotopes 7–8 families are withing the structure of dominants. In the conditions of salinization (trophotopes De and E, and also on light sandy loam soils, the numbers of litter mesofauna decrease. Share of saprophages is minimum in trophotopes Dc and E, while it increases in trophotopes C, Dac, Dn

Manejo de soja transgênica com glifosato e imazetapir: efeito sobre a mesofauna e microbiota do solo

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Danilo Dufech Castilhos

2010-10-01

Full Text Available A estabilidade de diferentes organismos da mesofauna, como ácaros e colêmbolos, e a atividade microbiana do solo são indicadores de qualidade físico-química e biológica do solo. Este trabalho teve por objetivo avaliar o efeito de métodos de controle de plantas concorrentes sobre a qualidade do solo cultivado com soja transgênica. Neste contexto, foram cultivados dois genótipos de soja, geneticamente modificada (GMRR BRS 244 RR e não modificada (NM BRS 154, no Centro Agropecuário da Palma da Universidade Federal de Pelotas (CAP, nas safras de 2005/2006 e 2006/2007. Para o controle de plantas daninhas, testaram-se, tratamentos com glifosato, imazetapir e capina. Avaliaram-se populações de ácaros e colêmbolos, o carbono da biomassa microbiana, a respiração basal e o quociente metabólico do solo. Verificou-se que a aplicação dos herbicidas, principalmente de glifosato, em soja BRS 244 RR cultivada em Planossolo resultou em desestabilidade da mesofauna e maior atividade da biomassa microbiana.

Effects of agricultural practices of three crops on the soil communities under Mediterranean conditions: field evaluation.

Science.gov (United States)

Leitão, Sara; José Cerejeira, Maria; Abreu, Manuela; Sousa, José Paulo

2014-05-01

Sustainable agricultural production relies on soil communities as the main actors in key soil processes necessary to maintain sustainable soil functioning. Soil biodiversity influences soil physical and chemical characteristics and thus the sustainability of crop and agro-ecosystems functioning. Agricultural practices (e.g.: soil tillage, pesticides and fertilizer applications, irrigation) may affects negatively or positively soil biodiversity and abundances by modifying the relationships between organisms in the soil ecosystem. The present study aimed to study the influence of agricultural practices of three crops (potato, onion and maize) under Mediterranean climate conditions on soil macro- and mesofauna during their entire crop cycles. Effects on soil communities were assessed at a higher tier of environmental risk assessment comprising field testing of indigenous edaphic communities in a selected study-site located in a major agriculture region of Central Portugal, Ribatejo e Oeste, neighbouring protected wetlands. A reference site near the agricultural field site was selected as a Control site to compare the terrestrial communities' composition and variation along the crop cycle. The field soil and Control site soil are sandy loam soils. Crops irrigation was performed by center-pivot (automated sprinkler that rotates in a half a circle area) and by sprinklers. Soil macro- and mesofauna were collected at both sites (field and Control) using two methodologies through pitfall trapping and soil sampling. The community of soil macro- and mesofauna of the three crops field varied versus control site along the crops cycles. Main differences were due to arachnids, coleopterans, ants and adult Diptera presence and abundance. The feeding activity of soil fauna between control site and crop areas varied only for potato and onion crops vs. control site but not among crops. Concentration of pesticides residues in soil did not cause apparent negative effects on the soil

Diversity of the soil biota in burned areas of southern taiga forests (Tver oblast)

Science.gov (United States)

Gongalsky, K. B.; Zaitsev, A. S.; Korobushkin, D. I.; Saifutdinov, R. A.; Yazrikova, T. E.; Benediktova, A. I.; Gorbunova, A. Yu.; Gorshkova, I. A.; Butenko, K. O.; Kosina, N. V.; Lapygina, E. V.; Kuznetsova, D. M.; Rakhleeva, A. A.; Shakhab, S. V.

2016-03-01

Relations between soil biota diversity and its contribution to the performance of some ecosystem functions were assessed based on the results obtained in undisturbed and burned spruce forests near the Central Forest Nature Biosphere Reserve (Tver oblast). In August 2014, in two 4-year-old burned areas, abiotic parameters of the soils, indicators of the state of the microbial communities, the number, taxonomic diversity, and the abundance of the main groups of soil invertebrates (testate amoebae, nematodes, enchytraeids, mites, collembolans, and the mesofauna as a whole) were determined. In the soils of the burned areas, higher CO2, CH4, and N2O emissions were observed. The number of bacterial cells remained similar, and the total length of active mycelium was not significantly different. All this implies a certain intensification of biogenic processes promoting the mobilization of carbon and nitrogen after fire. The number of most of the groups of soil animals was lower (not always significantly) in the burned area than that in the soils of the undisturbed forests. The changes in the taxonomic diversity were specific for each taxon studied. Overall, the diversity of invertebrates was related to the litter thickness. However, the high taxonomic diversity of soil fauna did not always correspond to the active functioning of the ecosystem. Thus, for some taxa, a quite close correlation was found, for instance, between the total number of species (of testate amoebae in particular) and the berry crop, as well as between the soil mesofauna population and the dead wood stock. The total diversity of the investigated taxa included in the detrital trophic web was the most reliable indicator of the carbon stock in the burned areas.

Wood ash application increases pH but does not harm the soil mesofauna

DEFF Research Database (Denmark)

Qin, Jiayi; Hovmand, Mads Frederik; Ekelund, Flemming

2017-01-01

Application of bioash from biofuel combustion to soil supports nutrient recycling, but may have unwanted and detrimental ecotoxicological side-effects, as the ash is a complex mixture of compounds that could affect soil invertebrates directly or through changes in their food or habitat conditions...... is the likely cause of effects while high pH and heavy metals is of minor importance.......Application of bioash from biofuel combustion to soil supports nutrient recycling, but may have unwanted and detrimental ecotoxicological side-effects, as the ash is a complex mixture of compounds that could affect soil invertebrates directly or through changes in their food or habitat conditions....... To examine this, we performed laboratory toxicity studies of the effects of wood-ash added to an agricultural soil and the organic horizon of a coniferous plantation soil with the detrivore soil collembolans Folsomia candida and Onychiurus yodai, the gamasid predaceous mite Hypoaspis aculeifer...

Soil , phyto and zoocenosis characteristics along an elevational gradient in the Alps (NW Italy)

Science.gov (United States)

Caimi, Angelo; Freppaz, Michele; Filippa, Gianluca; Buffa, Giorgio; Rivella, Enrico; Griselli, Bona; Parodi, Alessandra; Zanini, Ermanno

2010-05-01

From a global point of view, the distribution of biodiversity can be associated with climate. In particular, a majority of patterns of species diversity can be explained in terms of climatic gradients. Within a given mountain range, climate may affect the distribution of soils and the abundance and richness of plant species and mesofauna composition. In this study, promoted in the framework of an INTERREG Project "Biodiversità: una ricchezza da conservare" we investigate the soil, plant characteristics and mesofauna communities along two elevational gradient in Italian North Western Alps. Mountain environments are well-suited for such studies because of pronounced climatic gradients within short distances. The study areas, named San Bernardo and Vannino, are located in North Italy, close to the border of Switzerland (San Bernardo: N 46°09' E 08°10'; Vannino: N 46°23'E 08°22'). The first one ranged form 1617 m ASL to 2595 m ASL. while the second one ranged from 1786 to 2515 m ASL , with both a prevalent south aspect. Along both elevational gradients we selected 7 sites, with a vegetation cover ranging from coniferous forest (Larix, Picea and Abies) to high-elevation prairies. In each site, soil material (0-10 cm depth) was collected and in the laboratory, samples were dried and passed through a 2-mm sieve. The pH and the particle size distribution was determined following standard methods (SISS, 1998, 2000). Total C and N contents of the soil were measured with a C/H/N analyser (Elementar Vario EL). Data on the vegetation structure were collected close to each soil sampling points, covering a surface of 16 m2; each sampling site has been further divided into 4 sub-areas of 4 m2. Soil texture ranged between sand and loamy sand, without any obvious distribution with altitude. On average, in the Vannino transect soil texture was slightly coarser than at San Bernardo. A total of 118 vascular species were found at the sampling sites. Landolt ecological spectrum

Biodiversity and soil quality in agroecosystems: the use of a qualitative multi-attribute model

DEFF Research Database (Denmark)

Cortet, J.; Bohanec, M.; Griffiths, B.

2009-01-01

In ecological impact assessment, special emphasis is put on soil biology and estimating soil quality from the observed biological parameters. The aim of this study is to propose a tool easy to use for scientists and decision makers for agroecosystems soil quality assessment using these biological...... parameters. This tool was developed as a collaboration between ECOGEN (www.ecogen.dk) soil experts and decision analysts. Methodologically, we have addressed this goal using model-based Decision Support Systems (DSS), taking the approach of qualitative multi-attribute modelling. The approach is based...... on developing various hierarchical multiattribute models that consist of qualitative attributes and utility (aggregation) functions, represented by decision rules. The assessment of soil quality is based on two main indicators: (1) soil diversity (assessed through microfauna, mesofauna and macrofauna richness...

Tempo de Captura de Organismos da Mesofauna do Solo e seus Reflexos na Interpretação de Índices da Comunidade Edáfica

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Luiz Rodrigues Freire

2015-10-01

Full Text Available RESUMO A mesofauna edáfica compreende organismos de dimensões entre 100 μm e 2 mm, sendo importante avaliar os métodos utilizados para sua caracterização. Os objetivos deste trabalho foram definir o período de tempo de permanência do material de solo no extrator Berlese-Tüllgren para a captura dos organismos da mesofauna e determinar o tempo mínimo de extração para a correta utilização dos índices de Shannon, Simpson, Pielou e Margalef, empregados na avaliação da diversidade, dominância e equabilidade das comunidades da mesofauna. O estudo foi conduzido no Departamento de Solos do Instituto de Agronomia da Universidade Federal Rural do Rio de Janeiro, Seropédica, Rio de Janeiro, em terreno altamente antropizado. Foram instaladas parcelas experimentais com os seguintes tratamentos: feijão-de-porco (Canavalia ensiformis, mucuna-preta (Mucuna aterrima, feijão-bravo-do-Ceará (Canavalia brasiliensis, guandu (Cajanus cajan e vegetação espontânea, em delineamento de quadrado latino. Em cada uma das unidades experimentais, foram coletadas amostras formadas por serapilheira e material de solo, nos primeiros 5 cm da camada superficial do solo realizada um dia antes do plantio das leguminosas (outubro e, posteriormente, por ocasião do corte da parte aérea das plantas (março. As amostras foram submetidas a uma bateria de extratores do tipo Berlese-Tüllgren, por um período de 15 dias, realizando-se a contagem diária dos organismos. A partir da contagem e identificação em nível de grupo (Ordem/Família dos organismos capturados, foram determinados os índices de Margalef, Simpson, Shannon e Pielou, bem como verificou-se a correlação por ordem de Kendall entre os valores obtidos dia a dia até o 8º dia de extração, usando-se o índice de Shannon como referência. Concluiu-se que é possível a redução do tempo de permanência das amostras de material de solo nos funis Berlese-Tüllgren, não sendo recomendável a ado

Observing and modeling links between soil moisture, microbes and CH4 fluxes from forest soils

Science.gov (United States)

Christiansen, Jesper; Levy-Booth, David; Barker, Jason; Prescott, Cindy; Grayston, Sue

2017-04-01

Soil moisture is a key driver of methane (CH4) fluxes in forest soils, both of the net uptake of atmospheric CH4 and emission from the soil. Climate and land use change will alter spatial patterns of soil moisture as well as temporal variability impacting the net CH4 exchange. The impact on the resultant net CH4 exchange however is linked to the underlying spatial and temporal distribution of the soil microbial communities involved in CH4 cycling as well as the response of the soil microbial community to environmental changes. Significant progress has been made to target specific CH4 consuming and producing soil organisms, which is invaluable in order to understand the microbial regulation of the CH4 cycle in forest soils. However, it is not clear as to which extent soil moisture shapes the structure, function and abundance of CH4 specific microorganisms and how this is linked to observed net CH4 exchange under contrasting soil moisture regimes. Here we report on the results from a research project aiming to understand how the CH4 net exchange is shaped by the interactive effects soil moisture and the spatial distribution CH4 consuming (methanotrophs) and producing (methanogens). We studied the growing season variations of in situ CH4 fluxes, microbial gene abundances of methanotrophs and methanogens, soil hydrology, and nutrient availability in three typical forest types across a soil moisture gradient in a temperate rainforest on the Canadian Pacific coast. Furthermore, we conducted laboratory experiments to determine whether the net CH4 exchange from hydrologically contrasting forest soils responded differently to changes in soil moisture. Lastly, we modelled the microbial mediation of net CH4 exchange along the soil moisture gradient using structural equation modeling. Our study shows that it is possible to link spatial patterns of in situ net exchange of CH4 to microbial abundance of CH4 consuming and producing organisms. We also show that the microbial

Wood ash application increases pH but does not harm the soil mesofauna

NARCIS (Netherlands)

Qin, Jiayi; Hovmand, M.; Ekelund, Flemming; Rønn, Regin; Christensen, S.; Groot, de G.A.; Mortensen, L.H.; Skov, Simon; Henning Krogh, P.

2017-01-01

Application of bioash from biofuel combustion to soil supports nutrient recycling, but may have unwanted and detrimental ecotoxicological side-effects, as the ash is a complex mixture of compounds that could affect soil invertebrates directly or through changes in their food or habitat conditions.

Migration of 137Cs, 90Sr, 239,240Pu and 241Am in the chain soil-soil solution-plant. The soil-soil solution link

International Nuclear Information System (INIS)

Sokolik, G.A.; Ovsyannikova, S.V.; Kil'chitskaya, S.L.; Ehjsmont, E.A.; Zhukovich, N.V.; Kimlenko, I.M.; Duksina, V.V.; Rubinchik, S.Ya.

1999-01-01

The mobility of 137 Cs, 90 Sr, 239,240 Pu and 241 Am in the link soil-soil solution is analysed for different soil types on the basis of radionuclide distribution coefficients between solid and liquid soil phases. The distribution coefficients allow to differentiate soils in correlation with radionuclide migration rate from the solid phase to the soil solution. The reasons of different radionuclide mobility are considered

Linking biosensor responses to Cd, Cu and Zn partitioning in soils

International Nuclear Information System (INIS)

Dawson, J.J.C.; Campbell, C.D.; Towers, W.; Cameron, C.M.; Paton, G.I.

2006-01-01

Soils bind heavy metals according to fundamental physico-chemical parameters. Bioassays, using bacterial biosensors, were performed in pore waters extracted from 19 contrasting soils individually amended with Cd, Cu and Zn concentrations related to the EU Sewage Sludge Directive. The biosensors were responsive to pore waters extracted from Zn amended soils but less so to those of Cu and showed no toxicity to pore water Cd at these environmentally relevant amended concentrations. Across the range of soils, the solid-solution heavy metal partitioning coefficient (K d ) decreased (p d values. Gompertz functions of Cu and Zn, K d values against luminescence explained the relationship between heavy metals and biosensors. Consequently, biosensors provide a link between biologically defined hazard assessments of metals and standard soil-metal physico-chemical parameters for determining critical metal loadings in soils. - Biosensors link biological hazard assessments of metals in soils with physico-chemical partitioning

Qualitative and quantitative data concerning the edaphic mesofauna in the forest ecosystems from the middle section of the Prut riverside

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CĂLUGĂR Adina

2006-09-01

Full Text Available The paper contains the results of some researches devoted to the diversity of the edaphic mesofauna, with a view to estimate the effects induced by secondary aridization phenomenon. This study has been developed in the middle section of Prut riverside, in natural forests and forest plantations. It was realized a comparison between the natural habitats and those exposed to the drought phenomenon, because of their emplacement, out of the built dike. It has been analyzed four orders of mites (Oribatida, Gamasida, Actinedida and Acaridida and one order of insects (Collembola; we are taken into consideration other groups of microarthropods, too.

1169-IJBCS-Article-Fabian Ikpa

African Journals Online (AJOL)

KODJIO NORBERT

Diversity of mesofauna and macrofauna in protected and disturbed soils of ... soil habitats that have been depleted by human activities in ecological areas ..... Role of earthworms in soil fertility maintenance through the production of biogenic.

Links between matrix bulk density, macropore characteristics and hydraulic behavior of soils

DEFF Research Database (Denmark)

Katuwal, Sheela; Møldrup, Per; Lamandé, Mathieu

2013-01-01

characteristics on soil hydraulic functions has rarely been studied. With the objective of studying the links between these parameters we quantified macropore characteristics of intact soil columns (19 cm diameter x 20 cm high) from two agricultural field sites (Silstrup and Faardrup) in Denmark using coarse...... resolution X-ray CT and linked them with laboratory measurements of air permeability and leaching experiment. In addition to macropore characteristics, we also quantified the CT-number of the matrix as a measure of the bulk density of the matrix, i.e., excluding macropores in the soil. Soils from the two...

Study of microarthropod communities to assess soil quality in different managed vineyards

Science.gov (United States)

Gagnarli, Elena; Vignozzi, Nadia; Valboa, Giuseppe; Bouneb, Mabrouk; Corino, Lorenzo; Goggioli, Donatella; Guidi, Silvia; Lottero, Mariarosa; Tarchi, Franca; Simoni, Sauro

2014-05-01

Land use type influences the abundance and diversity of soil arthropods. The evaluation of the effects of different crop managements on soil quality is commonly requested; it can be pursued by means of the determination of communities' structure of edaphic fauna. The development and application of biological indices may represent an efficient mean to assess soil quality. We evaluated the effect of crop managements (organic and Integrated Pest Management-IPM) in some vineyards in Piedmont (Italy) on soil biota in relation to some physical and chemical characteristics of the soil. The study was performed in eleven sites, including seven organic and four IPM managed vineyards located in the Costigliole d'Asti area. Samplings were carried out during the winter 2011 and the spring 2012. Soil samples were collected using a cylindrical soil core sampler (3cm diameter x 30cm height): each sample was a cylindrical soil core which was equally subdivided to study arthropod communities at different depth ranges. Additional samples were collected and analyzed for the following soil physical and chemical properties: texture (sedigraph method), pH (1:2.5 soil/water), total organic carbon (TOC), total nitrogen (NT) and calcium carbonate (dry combustion by CN analyzer). The extraction of microarthropods was performed using the selector Berlese-Tullgren. All specimens were counted and determined up to the order level. The influence of soil properties and of agronomic practices on the abundance of mesofauna was evaluated by multivariate analysis (MANOVA). The biological soil quality was also defined through the determination of biotic indices such as the qualitative and quantitative QBSar (Quality Biological Soil - arthropods), and biodiversity indices such as species richness and indices of Shannon-Wiener (H') and Simpson (D). Overall, more than four thousands arthropods were collected and the highest abundance was in biological management with about 2:1 ratio (biological vs

Linking soil biology and chemistry in biological soil crust using isolate exometabolomics.

Science.gov (United States)

Swenson, Tami L; Karaoz, Ulas; Swenson, Joel M; Bowen, Benjamin P; Northen, Trent R

2018-01-02

Metagenomic sequencing provides a window into microbial community structure and metabolic potential; however, linking these data to exogenous metabolites that microorganisms process and produce (the exometabolome) remains challenging. Previously, we observed strong exometabolite niche partitioning among bacterial isolates from biological soil crust (biocrust). Here we examine native biocrust to determine if these patterns are reproduced in the environment. Overall, most soil metabolites display the expected relationship (positive or negative correlation) with four dominant bacteria following a wetting event and across biocrust developmental stages. For metabolites that were previously found to be consumed by an isolate, 70% are negatively correlated with the abundance of the isolate's closest matching environmental relative in situ, whereas for released metabolites, 67% were positively correlated. Our results demonstrate that metabolite profiling, shotgun sequencing and exometabolomics may be successfully integrated to functionally link microbial community structure with environmental chemistry in biocrust.

EFFECT OF DIFFERENT LEVELS AGROECOLOGICAL LOADS ON BIOCHEMICAL CHARACTERISTICS OF SOIL

Directory of Open Access Journals (Sweden)

A. V. Shchur

2016-01-01

Full Text Available Aim. To study the effect of different levels of agri-environmental loads on the enzymatic activity of the soil.Methods. Isolation of soil fauna was conducted by thermogradient. Ecological characteristics of soil biota community was determined by ecological indices. The enzymatic activity of soil under different crops and at different levels of agri-environmental loads in our experiments was determined by methods proven in the laboratory soil enzymology Institute of Experimental Botany name V.F. Kuprevich and Belorussian Research Institute for Soil Science and Agricultural Chemistry.Results. Community soil biota is polydominant character, as evidenced by the values of environmental indices. It does not set a significant impact on the community agrotechnological loads of soil micro and mesofauna. Absolute figures soil phosphatase activity averaged over all embodiments without recourse formation were higher by 63% compared with plowing. Invertase and catalase activity was much higher in stubble on all variants of the experiment and selection of terms. The content of peroxidase lower under pure steam. The laws have taken place in respect of peroxidase activity, marked for polifenoloksidase activity.Main conclusion. There was no major change in the ecological characteristics of soil biota. In the enzymatic activity of soil influenced by sampling time, fertilizer system, soil tillage methods and cultivated crops.

Study of microarthopod communities to assess soil quality in different managed vineyards

Science.gov (United States)

Gagnarli, E.; Goggioli, D.; Tarchi, F.; Guidi, S.; Nannelli, R.; Vignozzi, N.; Valboa, G.; Lottero, M. R.; Corino, L.; Simoni, S.

2015-01-01

Land use influences the abundance and diversity of soil arthropods. The evaluation of the impact of different management strategies on soil quality is increasingly requested. The determination of communities' structures of edaphic fauna can represent an efficient tool. In this study, in some vineyards in Piedmont (Italy), the effects of two different management systems, organic and integrated pest management (IPM), on soil biota were evaluated. As microarthropods living in soil surface are an important component of soil ecosystem interacting with all the other system components, a multi disciplinary approach was adopted by characterizing also some soil physical and chemical characteristics (soil texture, soil pH, total organic carbon, total nitrogen, calcium carbonate). Soil samplings were carried out on Winter 2011 and Spring 2012. All specimens were counted and determined up to the order level. The biological quality of the soil was defined through the determination of ecological indices, such as QBS-ar, species richness and indices of Shannon-Weaver, Pielou, Margalef and Simpson. The mesofauna abundance was affected by both the type of management and the soil texture. The analysis of microarthropod communities by QBS-ar showed higher values in organic than in IPM managed vineyards; in particular, the values registered in organic vineyards were similar to those characteristic of preserved soils.

Global soil-climate-biome diagram: linking soil properties to climate and biota

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Zhao, X.; Yang, Y.; Fang, J.

2017-12-01

As a critical component of the Earth system, soils interact strongly with both climate and biota and provide fundamental ecosystem services that maintain food, climate, and human security. Despite significant progress in digital soil mapping techniques and the rapidly growing quantity of observed soil information, quantitative linkages between soil properties, climate and biota at the global scale remain unclear. By compiling a large global soil database, we mapped seven major soil properties (bulk density [BD]; sand, silt and clay fractions; soil pH; soil organic carbon [SOC] density [SOCD]; and soil total nitrogen [STN] density [STND]) based on machine learning algorithms (regional random forest [RF] model) and quantitatively assessed the linkage between soil properties, climate and biota at the global scale. Our results demonstrated a global soil-climate-biome diagram, which improves our understanding of the strong correspondence between soils, climate and biomes. Soil pH decreased with greater mean annual precipitation (MAP) and lower mean annual temperature (MAT), and the critical MAP for the transition from alkaline to acidic soil pH decreased with decreasing MAT. Specifically, the critical MAP ranged from 400-500 mm when the MAT exceeded 10 °C but could decrease to 50-100 mm when the MAT was approximately 0 °C. SOCD and STND were tightly linked; both increased in accordance with lower MAT and higher MAP across terrestrial biomes. Global stocks of SOC and STN were estimated to be 788 ± 39.4 Pg (1015 g, or billion tons) and 63 ± 3.3 Pg in the upper 30-cm soil layer, respectively, but these values increased to 1654 ± 94.5 Pg and 133 ± 7.8 Pg in the upper 100-cm soil layer, respectively. These results reveal quantitative linkages between soil properties, climate and biota at the global scale, suggesting co-evolution of the soil, climate and biota under conditions of global environmental change.

Trophic position of soil nematodes in boreal forests as indicated by stable isotope analysis

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Kudrin, Alexey; Tsurikov, Sergey

2016-04-01

Despite the well-developed trophic classification of soil nematodes, their position in soil food webs is still little understood. Observed deviations from the typical feeding strategy indicate that a simplified trophic classification probably does not fully reflect actual trophic interactions. Furthermore, the extent and functional significance of nematodes as prey for other soil animals remains unknown. Stable isotope analysis (SIA) is powerful tool for investigating the structure of soil food webs, but its application to the study of soil nematodes has been limited to only a few studies. We used stable isotope analysis to gain a better understanding of trophic links of several groups of soil nematodes in two boreal forests on albeluvisol. We investigated four taxonomic groups of nematodes: Mononchida, Dorylaimida, Plectidae and Tylenchidae (mostly from the genus Filenchus), that according to the conventional trophic classification represent predators, omnivores, bacterivores and root-fungal feeders, respectively. To assess the trophic position of nematodes, we used a comparison against a set of reference species including herbivorous, saprophagous and predatory macro-invertebrates, oribatid and mesostigmatid mites, and collembolans. Our results suggest that trophic position of the investigated groups of soil nematodes generally corresponds to the conventional classification. All nematodes were enriched in 13C relative to Picea abies roots and litter, and mycorrhizal fungal mycelium. Root-fungal feeders Tylenchidae had δ15N values similar to those of earthworms, enchytraeids and Entomobrya collembolans, but slightly lower δ13C values. Bacterivorous Plectidae were either equal or enriched in 15N compared with saprophagous macroinvertebrates and most mesofauna species. Omnivorous Dorylaimida and predatory Mononchida were further enriched in 15N and their isotopic signature was similar to that of predatory arthropods. These data confirm a clear separation of

Underestimation of boreal soil carbon stocks by mathematical soil carbon models linked to soil nutrient status

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Ťupek, Boris; Ortiz, Carina A.; Hashimoto, Shoji; Stendahl, Johan; Dahlgren, Jonas; Karltun, Erik; Lehtonen, Aleksi

2016-08-01

Inaccurate estimate of the largest terrestrial carbon pool, soil organic carbon (SOC) stock, is the major source of uncertainty in simulating feedback of climate warming on ecosystem-atmosphere carbon dioxide exchange by process-based ecosystem and soil carbon models. Although the models need to simplify complex environmental processes of soil carbon sequestration, in a large mosaic of environments a missing key driver could lead to a modeling bias in predictions of SOC stock change.We aimed to evaluate SOC stock estimates of process-based models (Yasso07, Q, and CENTURY soil sub-model v4) against a massive Swedish forest soil inventory data set (3230 samples) organized by a recursive partitioning method into distinct soil groups with underlying SOC stock development linked to physicochemical conditions.For two-thirds of measurements all models predicted accurate SOC stock levels regardless of the detail of input data, e.g., whether they ignored or included soil properties. However, in fertile sites with high N deposition, high cation exchange capacity, or moderately increased soil water content, Yasso07 and Q models underestimated SOC stocks. In comparison to Yasso07 and Q, accounting for the site-specific soil characteristics (e. g. clay content and topsoil mineral N) by CENTURY improved SOC stock estimates for sites with high clay content, but not for sites with high N deposition.Our analysis suggested that the soils with poorly predicted SOC stocks, as characterized by the high nutrient status and well-sorted parent material, indeed have had other predominant drivers of SOC stabilization lacking in the models, presumably the mycorrhizal organic uptake and organo-mineral stabilization processes. Our results imply that the role of soil nutrient status as regulator of organic matter mineralization has to be re-evaluated, since correct SOC stocks are decisive for predicting future SOC change and soil CO2 efflux.

Soil health: looking for suitable indicators. What should be considered to assess the effects of use and management on soil health?

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Elke Jurandy Bran Nogueira Cardoso

2013-08-01

Full Text Available Soil Health refers to the ecological equilibrium and the functionality of a soil and its capacity to maintain a well balanced ecosystem with high biodiversity above and below surface, and productivity. To understand and use soil health as a tool for sustainability, physical, chemical, and biological properties must be employed to verify which respond to the soil use and management within a desired timescale. Attributes with a rapid response to natural or anthropogenic actions are considered good indicators of soil health. Among the physical indicators, soil texture, aggregation, moisture, porosity, and bulk density have been used, while among chemical indicators total C and N, mineral nutrients, organic matter, cation exchange capacity, among others are well established. However, most of them generally have a slow response, when compared to the biological ones, such as microbial biomass C and N, biodiversity, soil enzymes, soil respiration, etc., in addition to macro and mesofauna. Thus, a systemic approach based on different kinds of indicators (physical, chemical and biological in assessing soil health would be safer than using only one kind of attribute. Many human activities have caused desertification, loss of biodiversity, disruption of aggregates, loss of organic matter and nutrients, among others. Today, it is imperious to maintain soil health and productivity with increasing emphasis on reforestation and recuperation of degraded areas through the use of organic amendments, reintroduction of plants, soil fauna and microorganisms. This review focused on an integrative view on indicators of soil health to be used as tools for prediction of sustainability in production systems.

A Redescription of Acanthocreagris iranica (Pseudoscorpiones, Neobisiidae Inhabiting Soil Under Oak Trees in Zagros Forest, Western Iran

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Nassirkhani M.

2017-04-01

Full Text Available During study on soil mesofauna in Choqa Sabz Forest and Dalab Protected Area in Ilam Province (western Iran, the following pseudoscorpions belonging to four families were collected and identified: Chthonius (Chthonius shelkovnikovi Redikorzev, 1930, Chthonius (Ephippiochthonius negarinae Nassirkhani and Vafai, 2015, Paramenthus nanus Mahnert, 2007, Cardiolpium asiaticum (Dashdamirov, 1990, and Acanthocreagris iranica Beier, in Mahnert 1976. All of these species are new to the fauna of western Iran. In this survey, the adults of A. iranica collected from Ilam and Lorestan Provinces are redescribed and figured. Additionally, its tritonymph and deutonymph are briefly described.

Linking biological soil crust diversity to ecological functions

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Glaser, Karin; Borchhardt, Nadine; Schulz, Karoline; Mikhailyuk, Tatiana; Baumann, Karen; Leinweber, Peter; Ulf, Karsten

2016-04-01

Biological soil crusts (BSCs) are an association of different microorganisms and soil particles in the top millimeters of the soil. They are formed by algae, cyanobacteria, microfungi, bacteria, bryophytes and lichens in various compositions. Our aim was to determine and compare the biodiversity of all occurring organisms in biogeographically different habitats, ranging from polar (both Arctic and Antarctic), subpolar (Scandinavia), temperate (Germany) to dry regions (Chile). The combination of microscopy and molecular techniques (next-generation sequencing) revealed highly diverse crust communities, whose composition clustered by region and correlates with habitat characteristics such as water content. The BSC biodiversity was then linked to the ecological function of the crusts. The functional role of the BSCs in the biogeochemical cycles of carbon, nitrogen and phosphorous is evaluated using an array of state of the art soil chemistry methods including Py-FIMS (pyrolysis field ionization mass spectrometry) and XANES (x-ray absorbance near edge structure). Total P as well as P fractions were quantified in all BSCs, adjacent soil underneath and comparable nearby soil of BSC-free areas revealing a remarkable accumulation of total phosphorous and a distinct pattern of P fractions in the crust. Further, we observed an indication of a different P-speciation composition in the crust compared with BSC-free soil. The data allow answering the question whether BSCs act as sink or source for these compounds, and how biodiversity controls the biogeochemical function of BSCs.

Verrucomicrobial community structure and abundance as indicators for changes in chemical factors linked to soil fertility.

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Navarrete, Acacio Aparecido; Soares, Tielle; Rossetto, Raffaella; van Veen, Johannes Antonie; Tsai, Siu Mui; Kuramae, Eiko Eurya

2015-09-01

Here we show that verrucomicrobial community structure and abundance are extremely sensitive to changes in chemical factors linked to soil fertility. Terminal restriction fragment length polymorphism fingerprint and real-time quantitative PCR assay were used to analyze changes in verrucomicrobial communities associated with contrasting soil nutrient conditions in tropical regions. In case study Model I ("Slash-and-burn deforestation") the verrucomicrobial community structures revealed disparate patterns in nutrient-enriched soils after slash-and-burn deforestation and natural nutrient-poor soils under an adjacent primary forest in the Amazonia (R = 0.819, P = 0.002). The relative proportion of Verrucomicrobia declined in response to increased soil fertility after slash-and-burn deforestation, accounting on average, for 4 and 2 % of the total bacterial signal, in natural nutrient-poor forest soils and nutrient-enriched deforested soils, respectively. In case study Model II ("Management practices for sugarcane") disparate patterns were revealed in sugarcane rhizosphere sampled on optimal and deficient soil fertility for sugarcane (R = 0.786, P = 0.002). Verrucomicrobial community abundance in sugarcane rhizosphere was negatively correlated with soil fertility, accounting for 2 and 5 % of the total bacterial signal, under optimal and deficient soil fertility conditions for sugarcane, respectively. In nutrient-enriched soils, verrucomicrobial community structures were related to soil factors linked to soil fertility, such as total nitrogen, phosphorus, potassium and sum of bases, i.e., the sum of calcium, magnesium and potassium contents. We conclude that community structure and abundance represent important ecological aspects in soil verrucomicrobial communities for tracking the changes in chemical factors linked to soil fertility under tropical environmental conditions.

Teaching About the Links Between Soils and Climate: An International Year of Soil Outreach by the Soil Science Society of America

Science.gov (United States)

Brevik, Eric C.

2015-04-01

Soil scientists are well aware of the intimate links that exist between soils and climate, but the same is not always true of the broader population. In an attempt to help address this, the Soil Science Society of America (SSSA) has designated the theme "Soils and Climate" for the month of November, 2015 as part of the SSSA International Year of Soil (IYS) celebration. The topic has been further subdivided into three subthemes: 1) carbon sequestration and greenhouse gases, 2) Soils and past environments, and 3) Desertification and drought. Each subtheme outreach has two parts 1) lesson plans that K-12 educators can use in their classrooms, and 2) materials that a trained soil scientist can present to the general public. Activities developed for the theme include classroom activities to accompany an online game that students can play to see how farm management choices influence greenhouse gas emissions, questions to go with a vermicomposting activity, and discussion session questions to go with a movie on the USA Dust Bowl. All materials are available online free of charge. The Soils and Climate materials can be found at https://www.soils.org/iys/12-month-resources/november; all of the SSSA IYS materials can be found at https://www.soils.org/iys.

Case study of microarthropod communities to assess soil quality in different managed vineyards

Science.gov (United States)

Gagnarli, E.; Goggioli, D.; Tarchi, F.; Guidi, S.; Nannelli, R.; Vignozzi, N.; Valboa, G.; Lottero, M. R.; Corino, L.; Simoni, S.

2015-07-01

Land use influences the abundance and diversity of soil arthropods. The evaluation of the impact of different management strategies on soil quality is increasingly sought, and the determination of community structures of edaphic fauna can represent an efficient tool. In the area of Langhe (Piedmont, Italy), eight vineyards characterized for physical and chemical properties (soil texture, soil pH, total organic carbon, total nitrogen, calcium carbonate) were selected. We evaluated the effect of two types of crop management, organic and integrated pest management (IPM), on abundance and biodiversity of microarthropods living at the soil surface. Soil sampling was carried out in winter 2011 and spring 2012. All specimens were counted and determined up to the order level. The biodiversity analysis was performed using ecological indexes (taxa richness, dominance, Shannon-Wiener, Buzas and Gibson's evenness, Margalef, equitability, Berger-Parker), and the biological soil quality was assessed with the BSQ-ar index. The mesofauna abundance was affected by both the type of management and sampling time. On the whole, a higher abundance was in organic vineyards (N = 1981) than in IPM ones (N = 1062). The analysis performed by ecological indexes showed quite a high level of biodiversity in this environment, particularly in May 2012. Furthermore, the BSQ-ar values registered were similar to those obtained in preserved soils.

Seasonal exposure to drought and air warming affects soil Collembola and mites.

Directory of Open Access Journals (Sweden)

Guo-Liang Xu

Full Text Available Global environmental changes affect not only the aboveground but also the belowground components of ecosystems. The effects of seasonal drought and air warming on the genus level richness of Collembola, and on the abundance and biomass of the community of Collembola and mites were studied in an acidic and a calcareous forest soil in a model oak-ecosystem experiment (the Querco experiment at the Swiss Federal Research Institute WSL in Birmensdorf. The experiment included four climate treatments: control, drought with a 60% reduction in rainfall, air warming with a seasonal temperature increase of 1.4 °C, and air warming + drought. Soil water content was greatly reduced by drought. Soil surface temperature was slightly increased by both the air warming and the drought treatment. Soil mesofauna samples were taken at the end of the first experimental year. Drought was found to increase the abundance of the microarthropod fauna, but reduce the biomass of the community. The percentage of small mites (body length ≤ 0.20 mm increased, but the percentage of large mites (body length >0.40 mm decreased under drought. Air warming had only minor effects on the fauna. All climate treatments significantly reduced the richness of Collembola and the biomass of Collembola and mites in acidic soil, but not in calcareous soil. Drought appeared to have a negative impact on soil microarthropod fauna, but the effects of climate change on soil fauna may vary with the soil type.

Seasonal Exposure to Drought and Air Warming Affects Soil Collembola and Mites

Science.gov (United States)

Xu, Guo-Liang; Kuster, Thomas M.; Günthardt-Goerg, Madeleine S.; Dobbertin, Matthias; Li, Mai-He

2012-01-01

Global environmental changes affect not only the aboveground but also the belowground components of ecosystems. The effects of seasonal drought and air warming on the genus level richness of Collembola, and on the abundance and biomass of the community of Collembola and mites were studied in an acidic and a calcareous forest soil in a model oak-ecosystem experiment (the Querco experiment) at the Swiss Federal Research Institute WSL in Birmensdorf. The experiment included four climate treatments: control, drought with a 60% reduction in rainfall, air warming with a seasonal temperature increase of 1.4°C, and air warming + drought. Soil water content was greatly reduced by drought. Soil surface temperature was slightly increased by both the air warming and the drought treatment. Soil mesofauna samples were taken at the end of the first experimental year. Drought was found to increase the abundance of the microarthropod fauna, but reduce the biomass of the community. The percentage of small mites (body length 0.20 mm) increased, but the percentage of large mites (body length >0.40 mm) decreased under drought. Air warming had only minor effects on the fauna. All climate treatments significantly reduced the richness of Collembola and the biomass of Collembola and mites in acidic soil, but not in calcareous soil. Drought appeared to have a negative impact on soil microarthropod fauna, but the effects of climate change on soil fauna may vary with the soil type. PMID:22905210

Seasonal exposure to drought and air warming affects soil Collembola and mites.

Science.gov (United States)

Xu, Guo-Liang; Kuster, Thomas M; Günthardt-Goerg, Madeleine S; Dobbertin, Matthias; Li, Mai-He

2012-01-01

Global environmental changes affect not only the aboveground but also the belowground components of ecosystems. The effects of seasonal drought and air warming on the genus level richness of Collembola, and on the abundance and biomass of the community of Collembola and mites were studied in an acidic and a calcareous forest soil in a model oak-ecosystem experiment (the Querco experiment) at the Swiss Federal Research Institute WSL in Birmensdorf. The experiment included four climate treatments: control, drought with a 60% reduction in rainfall, air warming with a seasonal temperature increase of 1.4 °C, and air warming + drought. Soil water content was greatly reduced by drought. Soil surface temperature was slightly increased by both the air warming and the drought treatment. Soil mesofauna samples were taken at the end of the first experimental year. Drought was found to increase the abundance of the microarthropod fauna, but reduce the biomass of the community. The percentage of small mites (body length ≤ 0.20 mm) increased, but the percentage of large mites (body length >0.40 mm) decreased under drought. Air warming had only minor effects on the fauna. All climate treatments significantly reduced the richness of Collembola and the biomass of Collembola and mites in acidic soil, but not in calcareous soil. Drought appeared to have a negative impact on soil microarthropod fauna, but the effects of climate change on soil fauna may vary with the soil type.

Evaluación de sistemas agroecológicos mediante indicadores biológicos de la calidad del suelo: mesofauna edáfica

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Ana Socarrás

Full Text Available Se evaluó el impacto de los métodos agroecológicos a través de la variación de la mesofauna del suelo, en una finca con manejo integrado ganadería-agricultura (en Cangrejeras, provincia Artemisa. Se seleccionaron tres sistemas de manejo: área de pastizal, designada como área control, y con más de 20 años de establecida; área de forraje, sembrada en forma de mosaico, con pequeñas parcelas de cultivos perennes, y sometida a un tratamiento de abono orgánico; y área de policultivos, con un sistema de rotación de cultivos de ciclo corto y aplicación de compost. Los muestreos se efectuaron a los seis y ocho años de haber realizado las transformaciones en las áreas de forraje y cultivo, en ambas estaciones del año. Se tomaron cinco muestras en cada sistema, a una profundidad de 0-10 cm, según un diseño completamente aleatorizado. Por lo general en las áreas de forraje y pastizal, en cuanto a las relaciones oribátidos/astigmados, oribátidos/prostigmados y astigmados/mesostigmados (en ambas estaciones y años de transformación, dominaron los grupos edáficos que constituyen indicadores de estabilidad y fertilidad del suelo (oribátidos y mesostigmados, al estar favorecidos por la incorporación de la materia orgánica y una mayor cobertura del suelo, lo cual estimula que la mesofauna recobre condiciones de mayor estabilidad. En el área de policultivo predominaron los grupos indicadores de la inestabilidad e infertilidad del suelo (astigmados y prostigmados, ya que la rotación de cultivos y el manejo de las técnicas agroecológicas no garantizaron las condiciones que benefician el establecimiento de los otros grupos.

Direct and indirect effects of metal contamination on soil biota in a Zn-Pb post-mining and smelting area (S Poland)

International Nuclear Information System (INIS)

Kapusta, Pawel; Szarek-Lukaszewska, Grazyna; Stefanowicz, Anna M.

2011-01-01

Effects of metal contamination on soil biota activity were investigated at 43 sites in 5 different habitats (defined by substratum and vegetation type) in a post-mining area. Sites were characterised in terms of soil pH and texture, nutrient status, total and exchangeable metal concentrations, as well as plant species richness and cover, abundances of enchytraeids, nematodes and tardigrades, and microbial respiration and biomass. The concentrations of total trace metals were highest in soils developed on mining waste (metal-rich dolomite), but these habitats were more attractive than sandy sites for plants and soil biota because of their higher content of organic matter, clay and nutrients. Soil mesofauna and microbes were strongly dependent on natural habitat properties. Pollution (exchangeable Zn and Cd) negatively affected only enchytraeid density; due to a positive relationship between enchytraeids and microbes it indirectly reduced microbial activity. - Highlights: → Bioavailable zinc and cadmium reduce enchytraeid density. → Enchytraeids positively influence microbial respiration and biomass. → Total contents of heavy metals in soil are poor predictors of the distribution of plants and soil biota. - Elevated concentrations of exchangeable Zn and Cd reduce enchytraeid density and indirectly affect microbial activity adversely.

Direct and indirect effects of metal contamination on soil biota in a Zn-Pb post-mining and smelting area (S Poland)

Energy Technology Data Exchange (ETDEWEB)

Kapusta, Pawel, E-mail: p.kapusta@botany.pl [Department of Ecology, W. Szafer Institute of Botany, Polish Academy of Sciences, Lubicz 46, 31-512 Krakow (Poland); Szarek-Lukaszewska, Grazyna; Stefanowicz, Anna M. [Department of Ecology, W. Szafer Institute of Botany, Polish Academy of Sciences, Lubicz 46, 31-512 Krakow (Poland)

2011-06-15

Effects of metal contamination on soil biota activity were investigated at 43 sites in 5 different habitats (defined by substratum and vegetation type) in a post-mining area. Sites were characterised in terms of soil pH and texture, nutrient status, total and exchangeable metal concentrations, as well as plant species richness and cover, abundances of enchytraeids, nematodes and tardigrades, and microbial respiration and biomass. The concentrations of total trace metals were highest in soils developed on mining waste (metal-rich dolomite), but these habitats were more attractive than sandy sites for plants and soil biota because of their higher content of organic matter, clay and nutrients. Soil mesofauna and microbes were strongly dependent on natural habitat properties. Pollution (exchangeable Zn and Cd) negatively affected only enchytraeid density; due to a positive relationship between enchytraeids and microbes it indirectly reduced microbial activity. - Highlights: > Bioavailable zinc and cadmium reduce enchytraeid density. > Enchytraeids positively influence microbial respiration and biomass. > Total contents of heavy metals in soil are poor predictors of the distribution of plants and soil biota. - Elevated concentrations of exchangeable Zn and Cd reduce enchytraeid density and indirectly affect microbial activity adversely.

ANALYSIS OF SOIL AND DUST SAMPLES FOR POLYCHLORINATED BIPHENYLS BY ENZYME LINKED IMMUNOSORBENT ASSAY (ELISA)

Science.gov (United States)

An inhibition enzyme-linked immunosorbent assay (ELISA) was used to determine polychlorinated biphenyls (PCBs) in house dust and soil. Soil and house dust samples were analyzed for PCB by both gas chromatography/electron capture detection (GC/ECD) and ELISA methods. A correlati...

Link 'soil-plant' as critical in formation committed doses from uptake of long-lived radionuclides

International Nuclear Information System (INIS)

Kravetz, A. P.; Pavlenko, Y. A.; Grodzinsky, D. M.

1994-01-01

General algorithm of calculation dose from intake 137 Cs and 90 Sr depending upon level of pollution and agrochemical type of soil where trophycal chains to begin with, have been proposed. This methods consider link 'soil → plant' as critical in formation of doses from the intake long-lived radionuclides. Calculation of committed dose as function of type of soil and level of radionuclide pollution have been realized for seven main soil types of the White Russian and Ukrainian Wooded district. (author)

Link 'soil-plant' as critical in formation committed doses from uptake of long-lived radionuclides

Energy Technology Data Exchange (ETDEWEB)

Kravetz, A P; Pavlenko, Y A; Grodzinsky, D M [Institute of Cell Biology and Genetic Engineering AS Vasilcovsky st 31/17, Kiev 252022 (Ukraine)

1994-11-01

General algorithm of calculation dose from intake {sup 137}Cs and {sup 90}Sr depending upon level of pollution and agrochemical type of soil where trophycal chains to begin with, have been proposed. This methods consider link 'soil {yields} plant' as critical in formation of doses from the intake long-lived radionuclides. Calculation of committed dose as function of type of soil and level of radionuclide pollution have been realized for seven main soil types of the White Russian and Ukrainian Wooded district. (author)

Effect of acid deposition on soil animals and microorganisms: influence on structures and processes

International Nuclear Information System (INIS)

Schaefer, M.

1989-01-01

Principal effects of acid stress on the soil subsystem are increase or decrease in faunal and microfloral populations, changes in species assemblages and overall reductions in several soil microbiological processes. Little is known about the effects on nitrogen transformation (ammonification, nitrification, denitrification). Some possible but hypothetical scenarios for the effect of acidification stress on the forest ecosystem level are: (1) Inhibition of decomposition leads to an accumulation of litter. Immission and other disturbances may lead to humus disintegration and nitrate leaching; (2) Inhibition of mineralization reduces the availability of plant nutrients; (3) Decrease of the microfauna may cause disturbances of matter microcycling in the root zone; (4) Increase of the mesofauna may enhance the gracing pressure on mycorrhizal mycelia for even fine roots; (5) Decrease of the macrofauna (especially earthworms) lead to less bioturbation which impairs the buffer capacity of the litter and topsoil. A general outcome of liming experiments is stimulation of decomposition and mineralization: (1) Increased in nutrient arailability could lead to increased productivityin nutrient limited stands; (2) More irregular effects of animals on microbial activity may result in low stability of the soil-litter system and high liability to perturbations. (orig./vhe)

Does introduction of clover in an agricultural grassland affect the food base and functional diversity of Collembola?

NARCIS (Netherlands)

Annibale, D' Alessandra; Sechi, Valentina; Larsen, Thomas; Christensen, Søren; Krogh, Paul Henning; Eriksen, Jørgen

2017-01-01

Introduction of legumes (i.e. white clover) in agricultural grasslands is a common practice to improve yields, but how this affects soil fauna populations, particularly mesofauna, is still poorly understood. We investigated taxonomical and functional differences of Collembola communities between

Short term recovery of soil biological functions in a new vineyard cultivated in organic farming

Science.gov (United States)

Costantini, Edoardo; Agnelli, Alessandro; Fabiani, Arturo; Gagnarli, Elena; Mocali, Stefano; Priori, Simone; Simoni, Sauro; Valboa, Giuseppe

2014-05-01

Deep earthwork activities carried out before vineyard plantation completely upset soil profile and characteristics. The resulting soil features are often much more similar to the underlying substratum than original soil profile. The time needed to recover soil functions is ecologically relevant and affects vine phenology and grape yield, particularly in organic viticulture. The general aim of this research work was to investigate the time needed to recover soil functions after the earthworks made before vine plantation. This study compared for a four years period physical and chemical properties, microbial and mesofauna communities, in new and old vineyards, cultivated on the same soil type. The experiment was conducted in a farm of the Chianti Classico district (Central Italy), on hills of high altitude (400-500 m a.s.l.) on clayey-calcareous flysches, with stony and calcareous soils (Haplic Cambisol (Calcaric, Skeletic)). The reference vine cultivar was Sangiovese. The older vineyard was planted in 2000, after slope reshaping by bulldozing and back hoe ploughing down to about 0.8-1.0 m. The new vineyard was planted in 2011 after an equivalent earthwork carried out in the summer of 2009. Both vineyards were organically managed and only compost at the rate of 1,000 kg ha-1 -a was added every year. The new vineyard was periodically cultivated by mechanical tillage, while the older only at alternate rows. Soil samples from the first 15 cm depth were collected in 4 replicates in the younger as well as in the older vineyard during the springtime of 2010-2013; in the older vineyard, two samples were from the periodically cultivated swaths and two under permanent grass cover. Samples were analysed for physical (particle size, field capacity, wilting point), chemical (pH, electrical conductivity, lime, active lime, organic carbon, total nitrogen), microbiological (soil respiration, microbial biomass, DGGE), and mesofauna features (abundance, taxa richness, BSQ index and

Do soil organisms affect aboveground litter decomposition in the semiarid Patagonian steppe, Argentina?

Science.gov (United States)

Araujo, Patricia I; Yahdjian, Laura; Austin, Amy T

2012-01-01

Surface litter decomposition in arid and semiarid ecosystems is often faster than predicted by climatic parameters such as annual precipitation or evapotranspiration, or based on standard indices of litter quality such as lignin or nitrogen concentrations. Abiotic photodegradation has been demonstrated to be an important factor controlling aboveground litter decomposition in aridland ecosystems, but soil fauna, particularly macrofauna such as termites and ants, have also been identified as key players affecting litter mass loss in warm deserts. Our objective was to quantify the importance of soil organisms on surface litter decomposition in the Patagonian steppe in the absence of photodegradative effects, to establish the relative importance of soil organisms on rates of mass loss and nitrogen release. We estimated the relative contribution of soil fauna and microbes to litter decomposition of a dominant grass using litterboxes with variable mesh sizes that excluded groups of soil fauna based on size class (10, 2, and 0.01 mm), which were placed beneath shrub canopies. We also employed chemical repellents (naphthalene and fungicide). The exclusion of macro- and mesofauna had no effect on litter mass loss over 3 years (P = 0.36), as litter decomposition was similar in all soil fauna exclusions and naphthalene-treated litter. In contrast, reduction of fungal activity significantly inhibited litter decomposition (P soil fauna have been mentioned as a key control of litter decomposition in warm deserts, biogeographic legacies and temperature limitation may constrain the importance of these organisms in temperate aridlands, particularly in the southern hemisphere.

Transformations in occluded light fraction organic matter in a clayey oxisol; evidence from 13C-CCPMAS-NMR and &13C signature

NARCIS (Netherlands)

Roscoe, R.; Buurman, P.; Lagen, van B.; Velthorst, E.J.

2004-01-01

We hypothesised that, during occlusion inside granular aggregates of oxide-rich soils, the light fraction organic matter would Undergo a strong process of decomposition, either due to the slow process of aggregate formation and stabilisation or due to digestion in the macro- and meso-fauna guts.

iSOIL: Interactions between soil related sciences - Linking geophysics, soil science and digital soil mapping

Science.gov (United States)

Dietrich, Peter; Werban, Ulrike; Sauer, Uta

2010-05-01

High-resolution soil property maps are one major prerequisite for the specific protection of soil functions and restoration of degraded soils as well as sustainable land use, water and environmental management. To generate such maps the combination of digital soil mapping approaches and remote as well as proximal soil sensing techniques is most promising. However, a feasible and reliable combination of these technologies for the investigation of large areas (e.g. catchments and landscapes) and the assessment of soil degradation threats is missing. Furthermore, there is insufficient dissemination of knowledge on digital soil mapping and proximal soil sensing in the scientific community, to relevant authorities as well as prospective users. As one consequence there is inadequate standardization of techniques. At the poster we present the EU collaborative project iSOIL within the 7th framework program of the European Commission. iSOIL focuses on improving fast and reliable mapping methods of soil properties, soil functions and soil degradation risks. This requires the improvement and integration of advanced soil sampling approaches, geophysical and spectroscopic measuring techniques, as well as pedometric and pedophysical approaches. The focus of the iSOIL project is to develop new and to improve existing strategies and innovative methods for generating accurate, high resolution soil property maps. At the same time the developments will reduce costs compared to traditional soil mapping. ISOIL tackles the challenges by the integration of three major components: (i)high resolution, non-destructive geophysical (e.g. Electromagnetic Induction EMI; Ground Penetrating Radar, GPR; magnetics, seismics) and spectroscopic (e.g., Near Surface Infrared, NIR) methods, (ii)Concepts of Digital Soil Mapping (DSM) and pedometrics as well as (iii)optimized soil sampling with respect to profound soil scientific and (geo)statistical strategies. A special focus of iSOIL lies on the

Characterization and effects of cross-linked potassium polyacrylate as soil amendment

OpenAIRE

Sanz Gómez, Jorge

2016-01-01

Falta palabras clave Cross-linked potassium polyacrylate (Luquasorb®1280R) is a granular anionic superabsorbent polymer with the ability to absorb large amounts of water. The objectives of this study were the physicochemical characterization of the material and its effects when used as soil amendment together with the evaluation of the impact on agronomical parameters when it was applied to processing varieties of tomato (Solanum lycopersicum L.) grown under Mediterranean climate condit...

Bacterial and enchytraeid abundance accelerate soil carbon turnover along a lowland vegetation gradient in interior Alaska

Science.gov (United States)

Waldrop, M.P.; Harden, Jennifer W.; Turetsky, M.R.; Petersen, D.G.; McGuire, A.D.; Briones, M.J.I.; Churchill, A.C.; Doctor, D.H.; Pruett, L.E.

2012-01-01

Boreal wetlands are characterized by a mosaic of plant communities, including forests, shrublands, grasslands, and fens, which are structured largely by changes in topography and water table position. The soil associated with these plant communities contain quantitatively and qualitatively different forms of soil organic matter (SOM) and nutrient availability that drive changes in biogeochemical cycling rates. Therefore different boreal plant communities likely contain different soil biotic communities which in turn affect rates of organic matter decomposition. We examined relationships between plant communities, microbial communities, enchytraeids, and soil C turnover in near-surface soils along a shallow topographic soil moisture and vegetation gradient in interior Alaska. We tested the hypothesis that as soil moisture increases along the gradient, surface soils would become increasingly dominated by bacteria and mesofauna and have more rapid rates of C turnover. We utilized bomb radiocarbon techniques to infer rates of C turnover and the 13C isotopic composition of SOM and respired CO2 to infer the degree of soil humification. Soil phenol oxidase and peroxidase enzyme activities were generally higher in the rich fen compared with the forest and bog birch sites. Results indicated greater C fluxes and more rapid C turnover in the surface soils of the fen sites compared to the wetland forest and shrub sites. Quantitative PCR analyses of soil bacteria and archaea, combined with enchytraeid counts, indicated that surface soils from the lowland fen ecosystems had higher abundances of these microbial and mesofaunal groups. Fungal abundance was highly variable and not significantly different among sites. Microbial data was utilized in a food web model that confirmed that rapidly cycling systems are dominated by bacterial activity and enchytraeid grazing. However, our results also suggest that oxidative enzymes play an important role in the C mineralization process in

Soil Organic Matter and Soil Productivity: Searching for the Missing Link

Science.gov (United States)

Felipe G. Sanchez

1998-01-01

Soil-organic matter (SOM) is a complex array of components including soil fauna and flora at different stages of decomposition (Berg et al., 1982). Its concentration in soils can vary from 0.5% in mineral soils to almost 100% in peat soils (Brady, 1974). Organic matter (OM) in the surface mineral soil is considered a major determinant of forest ecosystem productivity...

Linking soil permeability and soil aggregate stability with root development: a pots experiment (preliminary results)

Science.gov (United States)

Vergani, Chiara; Graf, Frank; Gerber, Werner

2015-04-01

humidity of 75%, and at a night temperature of 17°C and relative humidity of 55% , with 15 hours of light per day. Four different growing periods have been distinguished (1, 2, 4 and 8 months). For each growing period 7 planted replicates have been set up, as well as 3 control pots with only bare soil treated the same way as the planted pots. After each growing period, the soil permeability was measured by means of a falling head procedure (Bagarello and Iovino, 2010) directly in the pots. Furthermore, soil aggregate stability was determined on soil samples applying a wet sieving method (Graf and Frei, 2013). Subsequently, root systems were collected and analyzed using different image software (Smartroot and Winrhizo). The permeability and soil aggregate stability values were finally linked with the root development stage and compared with field data coming from long-term stabilized slopes. Preliminary analysis reveals no significant influence of alder roots on both soil aggregate stability and hydraulic conductivity of soil after the one month growing period compared to the control. However, after two months we observed a decrease in the hydraulic conductivity values.

Soil stabilization linked to plant diversity and environmental context in coastal wetlands.

Science.gov (United States)

Ford, Hilary; Garbutt, Angus; Ladd, Cai; Malarkey, Jonathan; Skov, Martin W

2016-03-01

Plants play a pivotal role in soil stabilization, with above-ground vegetation and roots combining to physically protect soil against erosion. It is possible that diverse plant communities boost root biomass, with knock-on positive effects for soil stability, but these relationships are yet to be disentangled. We hypothesize that soil erosion rates fall with increased plant species richness, and test explicitly how closely root biomass is associated with plant diversity. We tested this hypothesis in salt marsh grasslands, dynamic ecosystems with a key role in flood protection. Using step-wise regression, the influences of biotic (e.g. plant diversity) and abiotic variables on root biomass and soil stability were determined for salt marshes with two contrasting soil types: erosion-resistant clay (Essex, southeast UK) and erosion-prone sand (Morecambe Bay, northwest UK). A total of 132 (30-cm depth) cores of natural marsh were extracted and exposed to lateral erosion by water in a re-circulating flume. Soil erosion rates fell with increased plant species richness ( R 2  = 0.55), when richness was modelled as a single explanatory variable, but was more important in erosion-prone ( R 2  = 0.44) than erosion-resistant ( R 2  = 0.18) regions. As plant species richness increased from two to nine species·m -2 , the coefficient of variation in soil erosion rate decreased significantly ( R 2  = 0.92). Plant species richness was a significant predictor of root biomass ( R 2  = 0.22). Step-wise regression showed that five key variables accounted for 80% of variation in soil erosion rate across regions. Clay-silt fraction and soil carbon stock were linked to lower rates, contributing 24% and 31%, respectively, to variation in erosion rate. In regional analysis, abiotic factors declined in importance, with root biomass explaining 25% of variation. Plant diversity explained 12% of variation in the erosion-prone sandy region. Our study indicates that soil stabilization

Metatranscriptomics reveals the diversity of genes expressed by eukaryotes in forest soils.

Directory of Open Access Journals (Sweden)

Coralie Damon

Full Text Available Eukaryotic organisms play essential roles in the biology and fertility of soils. For example the micro and mesofauna contribute to the fragmentation and homogenization of plant organic matter, while its hydrolysis is primarily performed by the fungi. To get a global picture of the activities carried out by soil eukaryotes we sequenced 2×10,000 cDNAs synthesized from polyadenylated mRNA directly extracted from soils sampled in beech (Fagus sylvatica and spruce (Picea abies forests. Taxonomic affiliation of both cDNAs and 18S rRNA sequences showed a dominance of sequences from fungi (up to 60% and metazoans while protists represented less than 12% of the 18S rRNA sequences. Sixty percent of cDNA sequences from beech forest soil and 52% from spruce forest soil had no homologs in the GenBank/EMBL/DDJB protein database. A Gene Ontology term was attributed to 39% and 31.5% of the spruce and beech soil sequences respectively. Altogether 2076 sequences were putative homologs to different enzyme classes participating to 129 KEGG pathways among which several were implicated in the utilisation of soil nutrients such as nitrogen (ammonium, amino acids, oligopeptides, sugars, phosphates and sulfate. Specific annotation of plant cell wall degrading enzymes identified enzymes active on major polymers (cellulose, hemicelluloses, pectin, lignin and glycoside hydrolases represented 0.5% (beech soil-0.8% (spruce soil of the cDNAs. Other sequences coding enzymes active on organic matter (extracellular proteases, lipases, a phytase, P450 monooxygenases were identified, thus underlining the biotechnological potential of eukaryotic metatranscriptomes. The phylogenetic affiliation of 12 full-length carbohydrate active enzymes showed that most of them were distantly related to sequences from known fungi. For example, a putative GH45 endocellulase was closely associated to molluscan sequences, while a GH7 cellobiohydrolase was closest to crustacean sequences, thus

Linking soil systems to societal value systems

Science.gov (United States)

Helming, Katharina; Daedlow, Katrin; Techen, Anja; Kaiser, David Brian

2017-04-01

Sustainable management of soils is needed to avoid soil degradation and to maintain soil functions. This requires the assessment of how human activities drive soil management, how soil management affect soil functions and soil degradation, which trade-offs occur and how they compromise sustainable development targets. In the frame of the German research programme "Soils as a sustainable resource for the bio-economy - BonaRes", we developed an enhanced approach of the DPSIR (driver-pressure-state-impact-response) cycle which helps to assess these interrelations. Because not all soil functions can be maximized simultaneously in space and time and trade-offs are inevitable, it depends on the societal value system to decide which management practices and respective soil functional performances are valued sustainably. We analysed the applicability of three valuation concepts being prominent in research about social-ecological systems, namely resource efficiency, ecosystem services, and ethics and equity. The concept of resource efficiency is based in the life-cycle thinking and is often applied at the level of the farming systems and in the context of bio-economy strategies. It covers the use of natural (water, energy, nutrients, land) and economic resources. At the landscape level, the concept of ecosystem services is prominent. Here, the contribution of soils to the provisioning, regulating and cultural services of the natural ecosystems is considered. Ethical considerations include the intrinsic values of nature as well as issues of local and global equity between different societal groups, generations, and localities. The three concepts cover different problem dimensions and complexity levels of soil management and decision making. Alone, none of them are capable to discover complex questions of sustainable soil management and development. Rather, the exact spatial and temporal framing of the sustainability problem at stake determines which combination of the value

A new method to simulate the hydrological state of soil under natural conditions Um novo método para simular o estado hidrológico do solo em condições naturais

Directory of Open Access Journals (Sweden)

Anna-Katharina Wild

2009-08-01

Full Text Available Micro, macro and mesofauna in the soil often respond to fluctuating environmental conditions, resulting in changes of abundance and community structure. Effects of changing soil parameters are normally determined with samples taken in the field and brought to the laboratory, i.e. where natural environmental conditions may not apply. We devised a method (STAFD - soil tubes for artificial flood and drought, which simulates the hydrological state of soil in situ using implanted cores. Control tubes were compared with treatment tubes in which floods of 15, 30, 60 and 90 days, and droughts of 60, 90 and 120 days were simulated in the field. Flooding and drought were found to reduce number of individuals in all soil faunal groups, but the response to drought was slower and not in proportion to the expected decrease of the water content. The results of the simulated floods in particular show the value of the STAFD method for the investigation of such extreme events in natural habitats.As micro, macro e mesofaunas no solo respondem frequentemente à variação das condições ambientais, o que resulta em alterações na abundância e na estrutura da comunidade. Os efeitos das alterações nos parâmetros do solo são normalmente determinados com amostras recolhidas no campo e trazidas ao laboratório, ou seja, onde as condições ambientais naturais podem não ser aplicáveis. Criamos um método (STAFD - tubos de amostra de solo para inundações e secas artificiais, que simula o estado hidrológico do solo in situ com núcleos implantados. As amostras de controle foram comparadas com amostras de tratamentos em que foram simuladas inundações de 15, 30, 60 e 90 dias e secas de 60, 90 e 120 dias no campo. Verificou-se que as inundações e a seca reduziram a quantidade de individuos em todos os grupos de fauna de solo, mas a resposta à seca foi mais lenta e não proporcional à redução prevista no teor de água. Os resultados das inunda

Linking spatial patterns of soil redistribution traced with 137Cs and soil nutrients in a Mediterranean mountain agroecosystem (NE Spain)

Science.gov (United States)

Quijano, Laura; Gaspar, Leticia; Navas, Ana

2016-04-01

fractions to analyze the SOC pool dynamics is presented in this study. A detailed field topographic survey and mapping of the spatial variability of soil properties and nutrient contents from soil analyses displayed similar spatial patterns of 137Cs and soil nutrients that also were directly and significantly correlated (p≤0.01). As much as 70% of the surface of the study field had lower values of 137Cs inventory indicating a predominance of soil loss linked to a generalized loss of soil nutrients. SOC gain was found in less than 1% of the study field and there was a large loss of SON compared to the undisturbed reference site. Higher and significant (p≤0.01) contents of soil nutrients were found in topsoil samples than in the bulk ones. Furthermore, there was an enrichment of the relative contribution of ACF to total SOC in sampling points where there was a 137Cs gain in both bulk and topsoil samples. Understanding patterns of soil nutrients can be useful for developing and implementing land management strategies to preserve soil quality in Mediterranean agricultural areas.

Estimating soil water-holding capacities by linking the Food and Agriculture Organization Soil map of the world with global pedon databases and continuous pedotransfer functions

Science.gov (United States)

Reynolds, C. A.; Jackson, T. J.; Rawls, W. J.

2000-12-01

Spatial soil water-holding capacities were estimated for the Food and Agriculture Organization (FAO) digital Soil Map of the World (SMW) by employing continuous pedotransfer functions (PTF) within global pedon databases and linking these results to the SMW. The procedure first estimated representative soil properties for the FAO soil units by statistical analyses and taxotransfer depth algorithms [Food and Agriculture Organization (FAO), 1996]. The representative soil properties estimated for two layers of depths (0-30 and 30-100 cm) included particle-size distribution, dominant soil texture, organic carbon content, coarse fragments, bulk density, and porosity. After representative soil properties for the FAO soil units were estimated, these values were substituted into three different pedotransfer functions (PTF) models by Rawls et al. [1982], Saxton et al. [1986], and Batjes [1996a]. The Saxton PTF model was finally selected to calculate available water content because it only required particle-size distribution data and results closely agreed with the Rawls and Batjes PTF models that used both particle-size distribution and organic matter data. Soil water-holding capacities were then estimated by multiplying the available water content by the soil layer thickness and integrating over an effective crop root depth of 1 m or less (i.e., encountered shallow impermeable layers) and another soil depth data layer of 2.5 m or less.

Allelopathic effect of new introduced biofuel crops on the soil biota: A comparative study

Science.gov (United States)

Heděnec, Petr; Frouz, Jan; Ustak, Sergej; Novotny, David

2015-04-01

Biofuel crops as an alternative to fossil fuels are a component of the energy mix in many countries. Many of them are introduced plants, so they pose a serious threat of biological invasions. Production of allelopathic compounds can increase invasion success by limiting co-occurring species in the invaded environment (novel weapons hypothesis). In this study, we focused on plant chemistry and production of allelopathic compounds by biofuel crops (hybrid sorrel Rumex tianschanicus x Rumex patientia and miscanthus Miscanthus sinensis) in comparison with invasive knotweed (Fallopia sachalinensis) and cultural meadow species. First, we tested the impact of leachates isolated from hybrid sorrel, miscanthus, knotweed and cultural meadow species compared to deionized water, used as a control, on seed germination of mustard (Sinapis arvensis) and wheat (Triticum aestivum) cultivated on sand and soil. Secondly, we studied the effect of leachates on the growth of soil fungal pathogens Fusarium culmorum, Rhizoctonia solani, Sclerotinia solani and Cochliobolus sativus. Finally, we tested the effect of litter of hybrid sorrel, miscanthus, knotweed and cultural meadow litter mixed with soil on population growth of Enchytraeus crypticus and Folsomia candida. Miscanthus and knotweed litter had a higher C:N ratio than the control meadow and hybrid sorrel litter. Miscanthus and hybrid sorrel litter had a higher content of phenols than knotweed and cultural meadow litter. Leachates from hybrid sorrel, miscanthus and knotweed biomass significantly decreased seed germination of wheat and mustard in both substrates. Soil fungal pathogens grew less vigorously on agar enriched by leachates from both biofuel crops than on agar enriched by knotweed and leachates. Litter from hybrid sorrel, miscanthus and knotweed significantly altered (both ways) the population growth of the soil mesofauna.

Soil-Web: An online soil survey for California, Arizona, and Nevada

Science.gov (United States)

Beaudette, D. E.; O'Geen, A. T.

2009-10-01

Digital soil survey products represent one of the largest and most comprehensive inventories of soils information currently available. The complex structure of these databases, intensive use of codes and scientific jargon make it difficult for non-specialists to utilize digital soil survey resources. A project was initiated to construct a web-based interface to digital soil survey products (STATSGO and SSURGO) for California, Arizona, and Nevada that would be accessible to the general public. A collection of mature, open source applications (including Mapserver, PostGIS and Apache Web Server) were used as a framework to support data storage, querying, map composition, data presentation, and contextual links to related materials. Application logic was written in the PHP language to "glue" together the many components of an online soil survey. A comprehensive website ( http://casoilresource.lawr.ucdavis.edu/map) was created to facilitate access to digital soil survey databases through several interfaces including: interactive map, Google Earth and HTTP-based application programming interface (API). Each soil polygon is linked to a map unit summary page, which includes links to soil component summary pages. The most commonly used soil properties, land interpretations and ratings are presented. Graphical and tabular summaries of soil profile information are dynamically created, and aid with rapid assessment of key soil properties. Quick links to official series descriptions (OSD) and other such information are presented. All terminology is linked back to the USDA-NRCS Soil Survey Handbook which contains extended definitions. The Google Earth interface to Soil-Web can be used to explore soils information in three dimensions. A flexible web API was implemented to allow advanced users of soils information to access our website via simple web page requests. Soil-Web has been successfully used in soil science curriculum, outreach activities, and current research projects

Linking plants, fungi and soil mechanics

Science.gov (United States)

Yildiz, Anil; Graf, Frank

2017-04-01

Plants provide important functions in respect soil strength and are increasingly considered for slope stabilisation within eco-engineering methods, particularly to prevent superficial soil failure. The protective functions include hydrological regulation through interception and evapo-transpiration as well as mechanical stabilisation through root reinforcement and, to a certain extent, chemical stabilisation through sticky metabolites. The ever-growing application of plants in slope stabilisation demanded more precise information of the vegetation effects and, concomitant, led the models for quantifying the reinforcement shoot up like mushrooms. However, so far, the framework and interrelationships for both the role of plants and the quantification concepts have not been thoroughly analysed and comprehensively considered, respectively, often resulting in unsatisfactory results. Although it seems obvious and is implicitly presupposed that the plant specific functions related to slope stability require growth and development, this is anything but given, particularly under the often hostile conditions dominating on bare and steep slopes. There, the superficial soil layer is often characterised by a lack of fines and missing medium-sized and fine pores due to an unstable soil matrix, predominantly formed by coarse grains. Low water retention capacity and substantial leaching of nutrients are the adverse consequences. Given this general set-up, sustainable plant growth and, particularly, root development is virtually unachievable. At exactly this point mycorrhizal fungi, the symbiotic partners of almost all plants used in eco-engineering, come into play. Though, they are probably well-known within the eco-engineering community, mycorrhizal fungi lead a humble existence. This is in spite of the fact that they supply their hosts with water and nutrients, improving the plant's ability to master otherwise unbridgeable environmental conditions. However, in order to support

Soil microarthropods and their bioindicator value regarding the bio-edaphic conditions in forest ecosystems of Danube Delta

Directory of Open Access Journals (Sweden)

Călugăr A.,

2016-05-01

Full Text Available The main objective of this study was to compare soil mesofauna communities in natural and anthropogenic forests from Danube Delta Biosphere Reserve and establish a baseline data in monitoring the disturbed sites. The abundance and diversity of edaphic microarthropods were analyzed in five plots, three of them being natural forests and two plantations (Canada poplar, and respectively willow. The mites from Trombidiformes and Oribatida were closely investigated being identified at family level. Qualitative analysis of edaphic microarthropods evidences numerical dominance of mites, excepting only one stand (Canada poplar plantation. Among mites Oribatida owns the biggest weight (76.6 - 94.1% of the total mites, followed by Trombidiformes or Mesostigmata. Among insects the collembolans hold higher density in the poplar plantation, and the lowest one in the willow plantation. Structure of mites communities differs between the investigated ecosystems both in quantitative and qualitative aspects depending on particular conditions of each plot.

Linking air and water transport in intact soils to macropore characteristics inferred from X-ray computed tomography

DEFF Research Database (Denmark)

Katuwal, S.; Nørgaard, Trine; Møldrup, Per

2015-01-01

Soil macropores often control fluid flow and solute transport, and quantification of macropore characteristics including their variability in space and time are essential to predict soil hydraulic and hydrogeochemical functions. In this study, measurements of air and solute transport properties...... and direct macropore visualization by X-ray CT scanning were carried out on 17 large (19-cm diam.; 20-cm length) undisturbed soil columns sampled across a field site (Silstrup, Denmark) with natural gradients in texture and density. Air permeability (ka) at in-situ water content and -20 hPa of matric......-porosity, suggesting that density is the main control of functional soil structure and gas and solute transport at the Silstrup site. Linking gas transport and chemical tracer experiments with X-ray CT based visualization and quantification of macro-porosity was found to be a powerful method to understand field scale...

Are there links between responses of soil microbes and ecosystem functioning to elevated CO2, N deposition and warming? A global perspective.

Science.gov (United States)

García-Palacios, Pablo; Vandegehuchte, Martijn L; Shaw, E Ashley; Dam, Marie; Post, Keith H; Ramirez, Kelly S; Sylvain, Zachary A; de Tomasel, Cecilia Milano; Wall, Diana H

2015-04-01

In recent years, there has been an increase in research to understand how global changes' impacts on soil biota translate into altered ecosystem functioning. However, results vary between global change effects, soil taxa, and ecosystem processes studied, and a synthesis of relationships is lacking. Therefore, here we initiate such a synthesis to assess whether the effect size of global change drivers (elevated CO2, N deposition, and warming) on soil microbial abundance is related with the effect size of these drivers on ecosystem functioning (plant biomass, soil C cycle, and soil N cycle) using meta-analysis and structural equation modeling. For N deposition and warming, the global change effect size on soil microbes was positively associated with the global change effect size on ecosystem functioning, and these relationships were consistent across taxa and ecosystem processes. However, for elevated CO2, such links were more taxon and ecosystem process specific. For example, fungal abundance responses to elevated CO2 were positively correlated with those of plant biomass but negatively with those of the N cycle. Our results go beyond previous assessments of the sensitivity of soil microbes and ecosystem processes to global change, and demonstrate the existence of general links between the responses of soil microbial abundance and ecosystem functioning. Further we identify critical areas for future research, specifically altered precipitation, soil fauna, soil community composition, and litter decomposition, that are need to better quantify the ecosystem consequences of global change impacts on soil biodiversity. © 2014 John Wiley & Sons Ltd.

Study of Acari and Collembola Populations in Four Cultivation Systems in Dourados - MS

Directory of Open Access Journals (Sweden)

Rosilda Mara Mussury

2002-09-01

Full Text Available The impact four cultivation systems on the soil fauna was studied, using Oribatida and Gamasida acarids as bioindicators and collembolan. The research was carried out in experimental fields, located in EMBRAPA - CPAO in Dourados, Centerwest of Brazil from July 1997 to December 1999. The constant pasture system presented smaller impact on the soil fauna followed by agricultural cattle rotation and a direct plantation system. In the conventional plantation series, the populational density of the mesofauna organisms was low, especially collembolan families.O impacto de quatro sistemas de cultivo sobre a fauna de solo foram estudados, utilizando-se como bioindicadores os acari Oribatida e Gamasida e os Collembola. A pesquisa foi conduzida em campos experimentais, localizados na EMBRAPA - CPAO no município de Dourados, MS, no período de julho de 1997 à dezembro de 1999. O sistema de pastagem contínua apresentou menor impacto sobre a fauna de solo seguido da rotação agricultura pecuária e do sistema de plantio direto. Nas sucessões do plantio convencional, a densidade populacional dos organismos da mesofauna foi baixa, em especial as famílias de colembolos.

"Interred with their bones" - linking soil micromorphology and chemistry to unlock the hidden archive of archaeological human burials

Science.gov (United States)

Brothwell, Don; Usai, Maria-Raimonda; Keely, Brendan; Pickering, Matt; Wilson, Clare

2010-05-01

"Interred with their bones" Acronym: InterArChive - an ERC-funded project *** " Friends, Romans, countrymen, lend me your ears; " I come to bury Caesar, not to praise him. " The evil that men do lives after them; " The good is oft 'interred with their bones'; " So let it be with Caesar. William Shakespeare, Julius Caesar, Act III, Scene 2. *** Background The state of decay within soils in archaeological graves is often such that degradable objects are not preserved in a condition that can be visually recognised. However, microscopic soil features, inorganic element distributions and organic residues can be measured. Thus, archaeological burial soils have the potential to reveal signatures of decay; pre-burial treatment; presence and nature of associated clothing and perishable artefacts; diet of the individual; cause of death; evidence of morbidity and drug-use. Aims • To develop and test a multidisciplinary approach linking soil micromorphology and chemistry to recover environmental and cultural information; • Revealing the hidden archaeological archive within the burial soil • Developing soil sampling and analysis recommendations for archaeological human burials Methods 1: Sampling and soil field description from archaeological sites contrasting in soil, geology, age, and culture and from experimental piglet burials 2: Microscopic/micromorphological analysis (micro-scale observations) of remains and features in burial soils. We will establish the order of occurrence, spatial patterns, displacement, mode of formation and decay of micromorphological features including exotic components, parasites, hair and remnants of footwear and clothing [cf. pilot study of soils from Yemen]; microfabrics and textural pedofeatures, also to facilitate resolution of body decay products from other accumulations. 3: Microprobe analysis (nano-scale) will generate elemental maps of soil thin sections, allowing identification of features with distinct chemical signatures

Soil ciliate bioassay for the pore water habitat. A missing link between microflora and earthworm testing in soil toxicity assessment

Energy Technology Data Exchange (ETDEWEB)

Berthold, A. [Lab. for Ecotoxicology, Univ. of Veterinary Medicine, Vienna (Austria); Jakl, T. [Chemicals Policy Unit, Federal Ministry of Agriculture, Forestry, Environment and Water Management, Vienna (Austria)

2002-07-01

Background, Scope and Goal. The chemical, pesticide and biocide legislation of the European Union assembles a variety of bioassays. Among the ecotoxicological tests involved, the testing strategy for the aquatic compartment builds up on three tests reflecting the main trophic levels (algae, Daphnia, fish). For the soil compartment at least one trophic level for a basic food chain is missing, namely between microflora and earthworms. Protozoa are an ideal missing link as they were shown to be the most prominent faunal contributors to nutrient cycling in soil ecosystems and as they represent the lacking first level consumers as well as the highly diverse microfauna. As protozoa inhabit the soil pore water, they can serve as direct indicators for the solved and thus bioavailable portion of xenobiotics. In order to widen the spectrum of available toxicity tests for a meaningful effect assessment for the soil compartment, a test with the soil ciliate Colpoda inflata (Ciliophora, Protozoa), introduced by Pratt et al. (1997), was improved. Methods. The novel improvements comprise a substantially refined inoculation and counting procedure, as well as the adaptation to yeast as a nutritional source. The test was designed to be rapid and easy to perform, in order to have both a higher degree of standardisation and reproducibility, as well as to be in compliance with international test guidelines. Results and Discussion. Five test substances, cadmium chloride, potassium dichromate, acetone, atrazine, and metolachlor, were used in single-compound, static, short-term exposure (24 h, 48 h) tests to examine the effect on the population growth of C. inflata. The median effective concentrations (EC50) were 0.17 to 0.26 mg/l for Cd, 34 to 63 mg/l for Cr, >3000 mg/l for acetone, 91-112 mg/l for atrazine and 83-119 mg/l for metolachlor. The equilibrium partitioning approach was used to extrapolate the results to total soil exposure and thus enable a sensitivity comparison to

Few apparent short-term effects of elevated soil temperature and increased frequency of summer precipitation on the abundance and taxonomic diversity of desert soil micro- and meso-fauna

Science.gov (United States)

Darby, B.J.; Neher, D.A.; Housman, D.C.; Belnap, J.

2011-01-01

Frequent hydration and drying of soils in arid systems can accelerate desert carbon and nitrogen mobilization due to respiration, microbial death, and release of intracellular solutes. Because desert microinvertebrates can mediate nutrient cycling, and the autotrophic components of crusts are known to be sensitive to rapid desiccation due to elevated temperatures after wetting events, we studied whether altered soil temperature and frequency of summer precipitation can also affect the composition of food web consumer functional groups. We conducted a two-year field study with experimentally-elevated temperature and frequency of summer precipitation in the Colorado Plateau desert, measuring the change in abundance of nematodes, protozoans, and microarthropods. We hypothesized that microfauna would be more adversely affected by the combination of elevated temperature and frequency of summer precipitation than either effect alone, as found previously for phototrophic crust biota. Microfauna experienced normal seasonal fluctuations in abundance, but the effect of elevated temperature and frequency of summer precipitation was statistically non-significant for most microfaunal groups, except amoebae. The seasonal increase in abundance of amoebae was reduced with combined elevated temperature and increased frequency of summer precipitation compared to either treatment alone, but comparable with control (untreated) plots. Based on our findings, we suggest that desert soil microfauna are relatively more tolerant to increases in ambient temperature and frequency of summer precipitation than the autotrophic components of biological soil crust at the surface.

The changes in the ecology and physiology of soil invertebrates under influences of radioactive contamination

International Nuclear Information System (INIS)

Maksimova, S.

2006-01-01

rates of soil mesofauna reproduction. Thus, our studies allowed us to estimate correctly the changes induced by radioactive contamination caused by Chernobyl nuclear accident at the level of soil invertebrate communities and to reveal the pattern of their disturbance under constant radiological pressure

Linking air and water transport in intact soils to macro-porosity by combining laboratory measurements and X-ray Computed Tomography

DEFF Research Database (Denmark)

Katuwal, Sheela; Norgaard, Trine; Møldrup, Per

-porosity (R2 = 0.80 for air permeability: R2= 0.61 for 5% arrival time) and macro-porosity of the restricting layer (R2=0.83 for air permeability: R2= 0.71 for 5% arrival time) over air-filled porosity and all the correlations were positive. The high positive correlation these air and water transport...... functions with macro-porosity stressed the importance of continuity and tortuosity of pores in air, water and solute flow and transport through the soils. Negative correlations of air permeability, 5% arrival time of tracer and macro-porosity were obtained with bulk density whereas with other soil physical......With an objective to link the hydraulic properties of soil with the soil structural properties, air permeability and 5% arrival time of a conservative tracer was measured for large undisturbed soil columns from the same agricultural field. The same soil columns were scanned with a medical scanner...

Linking diagnostic features to soil microbial biomass and respiration in agricultural grassland soil

NARCIS (Netherlands)

Richter, A.; Huallacháin, D.O.; Doyle, E.; Clipson, N.; Leeuwen, Van J.P.; Heuvelink, G.B.; Creamer, R.E.

2018-01-01

The functional potential of soil ecosystems can be predicted from the activity and abundance of the microbial community in relation to key soil properties. When describing microbial community dynamics, soil physicochemical properties have traditionally been used. The extent of correlations between

The Role of Plant-Parasitic Nematodes and Soil-Borne Fungi in the Decline of Ammophila-Arenaria (L) Link

NARCIS (Netherlands)

De Rooij van der Goes, P.C.E.M.

1995-01-01

In coastal foredunes, Ammophila arenaria (L.) Link grows vigorously when it is buried regularly by windblown sand and degenerates at stabilized sites. Nematodes and soil-borne fungi were found to be involved in its decline. In order to establish their role in the disease complex, seedlings of A.

Linking the composition of bacterial and archaeal communities to characteristics of soil and flora composition in the Atlantic rainforest

NARCIS (Netherlands)

Lima-Perim, Julia Elidia; Romagnoli, Emiliana Manesco; Dini-Andreote, Francisco; Durrer, Ademir; Dias, Armando Cavalcante Franco; Andreote, Fernando Dini

2016-01-01

The description of microbiomes as intrinsic fractions of any given ecosystem is an important issue, for instance, by linking their compositions and functions with other biotic and abiotic components of natural systems and hosts. Here we describe the archaeal and bacterial communities from soils of

Cracking up (and down): Linking multi-domain hydraulic properties with multi-scale hydrological processes in shrink-swell soils

Science.gov (United States)

Stewart, R. D.; Rupp, D. E.; Abou Najm, M. R.; Selker, J. S.

2017-12-01

Shrink-swell soils, often classified as Vertisols or vertic intergrades, are found on every continent except Antarctica and within many agricultural and urban regions. These soils are characterized by cyclical shrinking and swelling, in which bulk density and porosity distributions vary as functions of time and soil moisture. Crack networks that form in these soils act as dominant environmental controls on the movement of water, contaminants, and gases, making it important to develop fundamental understanding and tractable models of their hydrologic characteristics and behaviors. In this study, which took place primarily in the Secano Interior region of South-Central Chile, we quantified soil-water interactions across scales using a diverse and innovative dataset. These measurements were then utilized to develop a set of parsimonious multi-domain models for describing hydraulic properties and hydrological processes in shrink-swell soils. In a series of examples, we show how this model can predict porosity distributions, crack widths, saturated hydraulic conductivities, and surface runoff (i.e., overland flow) thresholds, by capturing the dominant mechanisms by which water moves through and interacts with clayey soils. Altogether, these models successfully link small-scale shrinkage/swelling behaviors with large-scale thresholds, and can be applied to describe important processes such as infiltration, overland flow development, and the preferential flow and transport of fluids and gases.

Soil as the Central Link in the Hydrological Cycle

Science.gov (United States)

Hillel, D.

2005-05-01

We present an overview of the function fulfilled by the soil in the chain of processes constituting the hydrological cycle in the terrestrial domain. Considering the height of the atmosphere, the thickness of the earth's rock mantle, and the depth of the ocean, we note that the soil is amazingly thin -- typically not much more than one meter thick. Yet, with its sponge-like porosity, internal surface area, and finite capacities to absorb, store, and transmit water and solutes, the soil determines the fate of precipitation reaching the ground surface - whether it flows over the land as runoff, is detained and made available to plant roots, or seeps downward to an aquifer. Without the soil as a buffer, rainfall would produce violent floods rather than sustained stream-flow. The soil also acts as a living filter, in which dissolved and suspended constituents are retained or transmuted into nutrients for the continual regeneration of life. Energy as well as matter is in constant flux as solar radiation is absorbed by the soil and growing plants and as heat is exchanged in evaporation and condensation as well as in biochemical reactions. Plant leaves absorb carbon dioxide from the air and synthesize it with soil-derived water to form the primary compounds of life, while oxygen emitted by the leaves makes the air breathable for animals, which in turn fertilize the plants. However unique in form and function, the soil is not an isolated body but interacts with the overlying atmosphere and underlying strata, and with surface and underground bodies of water. Especially important is the interrelation between the soil and the climate, enhancing or mitigating the greenhouse effect via the soil's uptake or release of radiatively active gases (carbon dioxide, methane, and nitrous oxide). For all these reasons, it is vital that we give full consideration to the soil's role in the context of hydrology. The problem to overcome, however, is the disjunct between the characteristic

Molecular distributions of phospholipid ester-linked fatty acids in a soil profile of the Dinghushan Biosphere Reserve

Directory of Open Access Journals (Sweden)

Shengyi Mao

2018-01-01

Full Text Available Phospholipid ester-linked fatty acids (PLFA were used to investigate the microbial ecology and its association with carbon accumulation in one soil profile from the Dinghushan Biosphere Preserve in south China, in order to probe the mechanisms that control the carbon accumulation at the depth of 0 - 20 cm in the Dinghushan forest soil profile. The data show that sulfate reducing bacteria (SRB occur in the top 10 cm, and methanotrophic bacteria and fungi are not present below 10 cm, and the gram-negative bacteria are reduced with gram-positive bacteria dominating at that depth; all of which indicated that the activities of some of the microorganisms were inhibited, from which we infer that the available carbon source and oxygen content of micro environment may be reduced below 10 cm of the profile. The shallow depth (top 10 cm of the soil anaerobic zone at the Wukesong profile, compared to the normal soil anaerobic zone (top 20 - 30 cm, is considered to be mainly the result of the high precipitation of acidic rain. The physicochemical reactions caused by acid rain in the soil system result in a decreased soil porosity, and a correspondingly decreased porosity-dependent oxygen concentration, leading to the thriving of SRB in the shallow depth. Although the increase of soil organic carbon stock is attributed to numerous factors, the decreasing rate of litter decomposition in the topsoil layer, together with the rise of the depth of the anaerobic zone, may play key roles in the carbon accumulation in the depth of 0 - 20 cm in the soil profile from the Dinghushan Biosphere Preserve.

Soil health in the Mediterranean region: Development and consolidation of a multifactor index to characterize the health of agricultural lands

Science.gov (United States)

Gil, Eshel; Guy, Levy; Oshri, Rinot; Michael, Borisover; Uri, Yermiyahu; Leah, Tsror; Hanan, Eizenberg; Tal, Svoray; Alex, Furman; Yael, Mishael; Yosef, Steinberger

2017-04-01

The link among between soil health, soil conservation, and food security, resilience, and function under a wide range of agricultural uses and different environmental systems, is at the heart of many ecofriendly research studies worldwide. We consider the health of soil as a function of its ability to provide ecosystem services, including agricultural production (provisional services); regulating natural cycles (regulation services) and as a habitat for plants (support services). Soil health is affected by a wide range of soil properties (biotic and abiotic) that maintain complex interactions among themselves. The decline in soil health includes degradation in its physical properties (e.g., deterioration of soil structure, compaction and sealing, water-repellency, soil erosion by water and wind), chemical properties (e.g., salinization, depletion of nutrients and organic matter content, accumulation of pollutants and reduction of the soils' ion exchange capacity) and biological properties (e.g., vulnerable populations of microflora, microfauna, and mesofauna, leading to a breach of ecological balance and biodiversity and, as a result, destruction of beneficial populations and pathogen outbreaks). Numerous studies show that agricultural practices have a major impact on soil functioning. Substituting longstanding tillage with no-till cropping and the amalgamation of cover crops in crop rotations were found to improve soil properties. Such changes contributed to the enhancement of the agronomical performance of the soil. On the other hand, these practices may result in lessened effectiveness of controlling perennial weeds. The evaluation of soil-health status in the Mediterranean region is very limited. Moreover, existing approaches for evaluation that have been used (such as the Cornell and Hany tests) do not give sufficient weight to important agronomic processes, such as soil erosion, salinization, sodification, spread of weeds in the fields (in particular, weeds

Phytotoxicity of trace metals in spiked and field-contaminated soils: Linking soil-extractable metals with toxicity.

Science.gov (United States)

Hamels, Fanny; Malevé, Jasmina; Sonnet, Philippe; Kleja, Dan Berggren; Smolders, Erik

2014-11-01

Soil tests have been widely developed to predict trace metal uptake by plants. The prediction of metal toxicity, however, has rarely been tested. The present study was set up to compare 8 established soil tests for diagnosing phytotoxicity in contaminated soils. Nine soils contaminated with Zn or Cu by metal mining, smelting, or processing were collected. Uncontaminated reference soils with similar soil properties were sampled, and series of increasing contamination were created by mixing each with the corresponding soil. In addition, each reference soil was spiked with either ZnCl2 or CuCl2 at several concentrations. Total metal toxicity to barley seedling growth in the field-contaminated soils was up to 30 times lower than that in corresponding spiked soils. Total metal (aqua regia-soluble) toxicity thresholds of 50% effective concentrations (EC50) varied by factors up to 260 (Zn) or 6 (Cu) among soils. For Zn, variations in EC50 thresholds decreased as aqua regia > 0.43 M HNO3  > 0.05 M ethylenediamine tetraacetic acid (EDTA) > 1 M NH4 NO3  > cobaltihexamine > diffusive gradients in thin films (DGT) > 0.001 M CaCl2 , suggesting that the last extraction is the most robust phytotoxicity index for Zn. The EDTA extraction was the most robust for Cu-contaminated soils. The isotopically exchangeable fraction of the total soil metal in the field-contaminated soils markedly explained the lower toxicity compared with spiked soils. The isotope exchange method can be used to translate soil metal limits derived from soils spiked with metal salts to site-specific soil metal limits. © 2014 SETAC.

Modeling Water and Nutrient Transport through the Soil-Root-Canopy Continuum: Explicitly Linking the Below- and Above-Ground Processes

Science.gov (United States)

Kumar, P.; Quijano, J. C.; Drewry, D.

2010-12-01

Vegetation roots provide a fundamental link between the below ground water and nutrient dynamics and above ground canopy processes such as photosynthesis, evapotranspiration and energy balance. The “hydraulic architecture” of roots, consisting of the structural organization of the root system and the flow properties of the conduits (xylem) as well as interfaces with the soil and the above ground canopy, affect stomatal conductance thereby directly linking them to the transpiration. Roots serve as preferential pathways for the movement of moisture from wet to dry soil layers during the night, both from upper soil layer to deeper layers during the wet season (‘hydraulic descent’) and vice-versa (‘hydraulic lift’) as determined by the moisture gradients. The conductivities of transport through the root system are significantly, often orders of magnitude, larger than that of the surrounding soil resulting in movement of soil-moisture at rates that are substantially larger than that through the soil. This phenomenon is called hydraulic redistribution (HR). The ability of the deep-rooted vegetation to “bank” the water through hydraulic descent during wet periods for utilization during dry periods provides them with a competitive advantage. However, during periods of hydraulic lift these deep-rooted trees may facilitate the growth of understory vegetation where the understory scavenges the hydraulically lifted soil water. In other words, understory vegetation with relatively shallow root systems have access to the banked deep-water reservoir. These inter-dependent root systems have a significant influence on water cycle and ecosystem productivity. HR induced available moisture may support rhizosphere microbial and mycorrhizal fungi activities and enable utilization of heterogeneously distributed water and nutrient resources To capture this complex inter-dependent nutrient and water transport through the soil-root-canopy continuum we present modeling

SoilEffects – start characterization of the experimental soil

OpenAIRE

Løes, Anne-Kristin; Johansen, Anders; Pommeresche, Reidun; Riley, Hugh

2013-01-01

This report describes the establishment, experimental plan and initial soil characteristics of the field experiment linked to the project “Effects of anaerobically digested manure on soil fertility - establishment of a long-term study under Norwegian conditions” (SoilEffects, 2010-14). The aim of the SoilEffects project is to identify potential risks and benefits for soil fertility when animal manure is anaerobically digested for biogas production. The field experiment was established on...

[Impact of heavy snow storm and freezing rain disasters on soil fauna in Chinese fir plantation in southern China].

Science.gov (United States)

Yan, Shao-kui; Zhang, Wei-dong; Liu, Yan-xin; Fu, Sheng-lei; Li, Yuan-liang; Wang, Si-long

2009-01-01

In January 2008, southern China suffered an unusual heavy snowstorm and freezing rain over a large area for almost a month long. This catastrophic event was the worst one in past 50 years, which brought the area a serious impact on the infrastructure, ecology, and environment. To understand the long-term impact of this catastrophic event on the forest ecosystems in this area, a field investigation was conducted on the soil fauna in a pure Chinese fir plantation and a mixed Chinese fir plantation-alder plantation in Huitong County of Hunan Province on March 23, 2008, the date 40 days after the heavy snowstorm and freezing rain. With the abundance and community composition as the main parameters and the monitoring data from the two plantations on March 23, 2007 as the reference, the flexibility and resistance of soil fauna to the disturbances of the catastrophic event was preliminarily evaluated. The results showed that there was a significant deviation of soil fauna communities in the two plantations from the reference. An outbreak increase in microfauna nematode abundance was found from 12216.9 ind x m(-2) to 118343.9 ind x m(-2) in pure Chinese fir plantation and from 25435.9 ind x m(-2) to 84573.0 ind x m(-2) in mixed Chinese fir plantation-alder plantation, while a 27.0% and 85.6% decrease of macrofauna abundance was found in the two plantations, respectively, compared with the reference. Mesofauna abundance also had a significant decrease in litter layer but not in soil. The abundance recovery displayed a trend from quick rate for microfauna to slow rate for macrofauna, which indicated that the soil fauna functional groups, in terms of body size, could be used as a vulnerable indicator in evaluating disturbance event and post-disturbance recovery. By using community ordinations, no shift in soil fauna community composition was detected 40 days after the catastrophic event, suggesting that the community composition of soil invertebrate had a high resistance to

Soil map density and a nation's wealth and income

NARCIS (Netherlands)

Hartemink, A.E.

2008-01-01

Little effort has been made to link soil mapping and soil data density to a nation’s welfare. Soil map density in 31 European countries and 44 low and middle income countries is linked to Gross Domestic Product (GDP) per capita and the number of soil scientists per country.

Effects of soil mesofauna and microclimate on nitrogen dynamics in ...

African Journals Online (AJOL)

Jane

2011-07-13

Jul 13, 2011 ... In this paper, carbon (C) and N dynamics in decomposing. Castanopsis ... between litter wet and dry weights divided by the dry weight and ..... 45. 55. 65. 75. EVB. COF. DWF. ALM sites. M e a n a n n u a. l a ir te m p e ra tu re.

Linking hard and soft traits: Physiology, morphology and anatomy interact to determine habitat affinities to soil water availability in herbaceous dicots.

Science.gov (United States)

Belluau, Michaël; Shipley, Bill

2018-01-01

Species' habitat affinities along environmental gradients should be determined by a combination of physiological (hard) and morpho-anatomical (soft) traits. Using a gradient of soil water availability, we address three questions: How well can we predict habitat affinities from hard traits, from soft traits, and from a combination of the two? How well can we predict species' physiological responses to drought (hard traits) from their soft traits? Can we model a causal sequence as soft traits → hard traits → species distributions? We chose 25 species of herbaceous dicots whose affinities for soil moisture have already been linked to 5 physiological traits (stomatal conductance and net photosynthesis measured at soil field capacity, water use efficiency, stomatal conductance and soil water potential measured when leaves begin to wilt). Under controlled conditions in soils at field capacity, we measured five soft traits (leaf dry matter content, specific leaf area, leaf nitrogen content, stomatal area, specific root length). Soft traits alone were poor predictors (R2 = 0.129) while hard traits explained 48% of species habitat affinities. Moreover, hard traits were significantly related to combinations of soft traits. From a priori biological knowledge and hypothesized ecological links we built a path model showing a sequential pattern soft traits → hard traits → species distributions and accounting for 59.6% (p = 0.782) of habitat wetness. Both direct and indirect causal relationships existed between soft traits, hard traits and species' habitat preferences. The poor predictive abilities of soft traits alone were due to the existence of antagonistic and synergistic direct and indirect effects of soft traits on habitat preferences mediated by the hard traits. To obtain a more realistic model applicable to a population level, it has to be tested in an experiment including species competition for water supply.

Cyanobacterial crusts linked to soil productivity under different grazing management practices in Northern Australia

Science.gov (United States)

Alchin, Bruce; Williams, Wendy

2015-04-01

sites. Nitrogen fixation rates were significantly higher in the wet season samples compared to the dry season. Rates of nitrogen fixation, mineralisable nitrogen and cyanobacterial biomass were comparative to other studies both in Australia and globally. Eleven of the twelve sites had higher plant-available (mineralisable) nitrogen in the 0-1 cm depth compared to the 1-5 cm depth. Nitrogen isotopes showed that the nitrogen concentration found in the surface soils (0-1 cm) from five sites originated from cyanobacterial nitrogen fixation. At the remaining sites the isotopic signatures were slightly more positive, indicative of fractionation. The results have substantiated the link between cyanobacteria and their contribution to carbon and nitrogen cycling across the northern Australian rangelands. The data also highlights the variability between sites and management practices that influence biogeochemical processes that affect soil productivity.

Linking measurements of biodegradability, thermal stability and chemical composition to evaluate the effects of management on soil organic matter

Science.gov (United States)

Gregorich, Ed; Gillespie, Adam; Beare, Mike; Curtin, Denis; Sanei, Hamed; Yanni, Sandra

2015-04-01

The stability of soil organic matter (SOM) as it relates to resistance to microbial degradation has important implications for nutrient cycling, emission of greenhouse gases, and C sequestration. Hence, there is interest in developing new ways to accurately quantify and characterise the labile and stable forms of soil organic C. Our objectives in this study were to evaluate and describe relationships among the biodegradability, thermal stability and chemistry of SOM in soil under widely contrasting management regimes. Samples from the same soil under permanent pasture, an arable cropping rotation, and chemical fallow were fractionated (sand: 2000-50 μm; silt: 50-5 μm, and clay: managements and that sand-associated organic matter was significantly more susceptible than that in the silt or clay fractions. Analysis by XANES showed accumulation of carboxylates and strong depletion of amides (protein) and aromatics in the fallow whole soil. Moreover, protein depletion was most significant in the sand fraction of the fallow soil. Sand fractions in fallow and cropped soils were, however, enriched in plant-derived phenols, aromatics and carboxylates compared to the sand fraction of pasture soils. In contrast, ketones, which have been identified as products of microbially-processed organic matter, were slightly enriched in the silt fraction of the pasture soil. These data suggest reduced inputs and cropping restrict the decomposition of plant residues and, without supplemental N additions, protein-N in native SOM is significantly mineralized in fallow systems to meet microbial C mineralization demands. Analytical pyrolysis showed distinct differences in the thermal stability of SOM among the size fractions and management treatments; it also showed that the loss of SOM generally involved dehydrogenation. The temperature at which half of the C was pyrolyzed showed strong correlation with mineralizable C and thus provides solid evidence for a link between the biological and

Ecosystem services of soil biota: In what context is a focus on soil biota meaningful?

Science.gov (United States)

Baveye, Philippe C.

2016-04-01

Over the last few years, the topic of the ecosystem services of soils has attracted considerable attention, in particular among researchers working on soil biota. A direct link is established explicitly in numerous articles between soil biota and specific ecosystem services, or between soil biodiversity and ecosystem services. A careful review of the literature indicates however that these links are, more often than not, strictly axiomatic, rather than based on actual observations. In fact, there are still at the moment virtually no measurements of ecosystem services of soils at any scale, measurements that would be required to establish such links. Furthermore, at a conceptual level, it is not clear to what extent the effect of soil biota in the delivery of ecosystem services can be separated from the contribution of other components of soil systems. Soil microorganisms, in particular, proliferate and are metabolically active in a pore space whose characteristics and dynamics could in principle have a profound effect on their activity. So also could the composition and spatial distribution of soil organic matter, or the spatial pattern of plant root propagation. By emphasizing the role of soil biota, at the exclusion of other aspects of soil systems, there is a risk that important features of the provision of ecosystem services by soils will be missed. In this talk (based in part on a workshop organized recently in France, and of a follow-up review article), an analysis of this general problem will be presented, as well as suggestions of how to avoid it by promoting truly interdisciplinary research involving not only soil ecologists but also physicists, hydrologists, and chemists.

Long-term rice cultivation stabilizes soil organic carbon and promotes soil microbial activity in a salt marsh derived soil chronosequence

Science.gov (United States)

Wang, Ping; Liu, Yalong; Li, Lianqing; Cheng, Kun; Zheng, Jufeng; Zhang, Xuhui; Zheng, Jinwei; Joseph, Stephen; Pan, Genxing

2015-01-01

Soil organic carbon (SOC) sequestration with enhanced stable carbon storage has been widely accepted as a very important ecosystem property. Yet, the link between carbon stability and bio-activity for ecosystem functioning with OC accumulation in field soils has not been characterized. We assessed the changes in microbial activity versus carbon stability along a paddy soil chronosequence shifting from salt marsh in East China. We used mean weight diameter, normalized enzyme activity (NEA) and carbon gain from straw amendment for addressing soil aggregation, microbial biochemical activity and potential C sequestration, respectively. In addition, a response ratio was employed to infer the changes in all analyzed parameters with prolonged rice cultivation. While stable carbon pools varied with total SOC accumulation, soil respiration and both bacterial and fungal diversity were relatively constant in the rice soils. Bacterial abundance and NEA were positively but highly correlated to total SOC accumulation, indicating an enhanced bio-activity with carbon stabilization. This could be linked to an enhancement of particulate organic carbon pool due to physical protection with enhanced soil aggregation in the rice soils under long-term rice cultivation. However, the mechanism underpinning these changes should be explored in future studies in rice soils where dynamic redox conditions exist. PMID:26503629

Modelling soil nitrogen: The MAGIC model with nitrogen retention linked to carbon turnover using decomposer dynamics

International Nuclear Information System (INIS)

Oulehle, F.; Cosby, B.J.; Wright, R.F.; Hruška, J.; Kopáček, J.; Krám, P.; Evans, C.D.; Moldan, F.

2012-01-01

We present a new formulation of the acidification model MAGIC that uses decomposer dynamics to link nitrogen (N) cycling to carbon (C) turnover in soils. The new model is evaluated by application to 15–30 years of water chemistry data at three coniferous-forested sites in the Czech Republic where deposition of sulphur (S) and N have decreased by >80% and 40%, respectively. Sulphate concentrations in waters have declined commensurately with S deposition, but nitrate concentrations have shown much larger decreases relative to N deposition. This behaviour is inconsistent with most conceptual models of N saturation, and with earlier versions of MAGIC which assume N retention to be a first-order function of N deposition and/or controlled by the soil C/N ratio. In comparison with earlier versions, the new formulation more correctly simulates observed short-term changes in nitrate leaching, as well as long-term retention of N in soils. The model suggests that, despite recent deposition reductions and recovery, progressive N saturation will lead to increased future nitrate leaching, ecosystem eutrophication and re-acidification. - Highlights: ► New version of the biogeochemical model MAGIC developed to simulate C/N dynamics. ► New formulation of N retention based directly on the decomposer processes. ► The new formulation simulates observed changes in nitrate leaching and in soil C/N. ► The model suggests progressive N saturation at sites examined. ► The model performance meets a growing need for realistic process-based simulations. - Process-based modelling of nitrogen dynamics and acidification in forest ecosystems.

Linking the Composition of Bacterial and Archaeal Communities to Characteristics of Soil and Flora Composition in the Atlantic Rainforest

Science.gov (United States)

Lima-Perim, Julia Elidia; Romagnoli, Emiliana Manesco; Dini-Andreote, Francisco; Durrer, Ademir; Dias, Armando Cavalcante Franco; Andreote, Fernando Dini

2016-01-01

The description of microbiomes as intrinsic fractions of any given ecosystem is an important issue, for instance, by linking their compositions and functions with other biotic and abiotic components of natural systems and hosts. Here we describe the archaeal and bacterial communities from soils of the Atlantic Rainforest in Brazil. Based on the comparison of three areas located along an altitudinal gradient—namely, Santa Virginia, Picinguaba and Restinga—we detected the most abundant groups of Bacteria (Acidobacteria and Proteobacteria) and Archaea (Thaumarchaeota, Crenarchaeota and Euryarchaeota). The particular composition of such communities in each of these areas was first evidenced by PCR-DGGE patterns [determined for Bacteria, Archaea and ammonia-oxidizing organisms—ammonia-oxidizing archaea (AOA) and bacteria (AOB)]. Moreover, sequence-based analysis provided a better resolution of communities, which indicated distinct frequencies of archaeal phyla and bacterial OTUs across areas. We found, as indicated by the Mantel test and multivariate analyses, a potential effect of the flora composition that outpaces the effect of soil characteristics (either physical and chemical) influencing the assembly of these microbial communities in soils. Our results indicate a collective role of the ecosystem underlying observed differences in microbial communities in these soils. Particularly, we posit that rainforest preservation also needs to take into account the maintenance of the soil biodiversity, as this is prompted to influence major processes that affect ecosystem functioning. PMID:26752633

Linking the Composition of Bacterial and Archaeal Communities to Characteristics of Soil and Flora Composition in the Atlantic Rainforest.

Science.gov (United States)

Lima-Perim, Julia Elidia; Romagnoli, Emiliana Manesco; Dini-Andreote, Francisco; Durrer, Ademir; Dias, Armando Cavalcante Franco; Andreote, Fernando Dini

2016-01-01

The description of microbiomes as intrinsic fractions of any given ecosystem is an important issue, for instance, by linking their compositions and functions with other biotic and abiotic components of natural systems and hosts. Here we describe the archaeal and bacterial communities from soils of the Atlantic Rainforest in Brazil. Based on the comparison of three areas located along an altitudinal gradient-namely, Santa Virginia, Picinguaba and Restinga-we detected the most abundant groups of Bacteria (Acidobacteria and Proteobacteria) and Archaea (Thaumarchaeota, Crenarchaeota and Euryarchaeota). The particular composition of such communities in each of these areas was first evidenced by PCR-DGGE patterns [determined for Bacteria, Archaea and ammonia-oxidizing organisms-ammonia-oxidizing archaea (AOA) and bacteria (AOB)]. Moreover, sequence-based analysis provided a better resolution of communities, which indicated distinct frequencies of archaeal phyla and bacterial OTUs across areas. We found, as indicated by the Mantel test and multivariate analyses, a potential effect of the flora composition that outpaces the effect of soil characteristics (either physical and chemical) influencing the assembly of these microbial communities in soils. Our results indicate a collective role of the ecosystem underlying observed differences in microbial communities in these soils. Particularly, we posit that rainforest preservation also needs to take into account the maintenance of the soil biodiversity, as this is prompted to influence major processes that affect ecosystem functioning.

Underestimation of soil carbon stocks by Yasso07, Q, and CENTURY models in boreal forest linked to overlooking site fertility

Science.gov (United States)

Ťupek, Boris; Ortiz, Carina; Hashimoto, Shoji; Stendahl, Johan; Dahlgren, Jonas; Karltun, Erik; Lehtonen, Aleksi

2016-04-01

The soil organic carbon stock (SOC) changes estimated by the most process based soil carbon models (e.g. Yasso07, Q and CENTURY), needed for reporting of changes in soil carbon amounts for the United Nations Framework Convention on Climate Change (UNFCCC) and for mitigation of anthropogenic CO2 emissions by soil carbon management, can be biased if in a large mosaic of environments the models are missing a key factor driving SOC sequestration. To our knowledge soil nutrient status as a missing driver of these models was not tested in previous studies. Although, it's known that models fail to reconstruct the spatial variation and that soil nutrient status drives the ecosystem carbon use efficiency and soil carbon sequestration. We evaluated SOC stock estimates of Yasso07, Q and CENTURY process based models against the field data from Swedish Forest Soil National Inventories (3230 samples) organized by recursive partitioning method (RPART) into distinct soil groups with underlying SOC stock development linked to physicochemical conditions. These models worked for most soils with approximately average SOC stocks, but could not reproduce higher measured SOC stocks in our application. The Yasso07 and Q models that used only climate and litterfall input data and ignored soil properties generally agreed with two third of measurements. However, in comparison with measurements grouped according to the gradient of soil nutrient status we found that the models underestimated for the Swedish boreal forest soils with higher site fertility. Accounting for soil texture (clay, silt, and sand content) and structure (bulk density) in CENTURY model showed no improvement on carbon stock estimates, as CENTURY deviated in similar manner. We highlighted the mechanisms why models deviate from the measurements and the ways of considering soil nutrient status in further model development. Our analysis suggested that the models indeed lack other predominat drivers of SOC stabilization

Initial contents of residue quality parameters predict effects of larger soil fauna on decomposition of contrasting quality residues

Directory of Open Access Journals (Sweden)

Ratikorn Sanghaw

2017-10-01

Full Text Available A 52-week decomposition study employing the soil larger fauna exclusion technique through litter bags of two mesh sizes (20 and 0.135 mm was conducted in a long-term (18 yr field experiment. Organic residues of contrasting quality of N, lignin (L, polyphenols (PP and cellulose (CL all in grams per kilogram: rice straw (RS: 4.5N, 22.2L, 3.9PP, 449CL, groundnut stover (GN: 21.2N, 71.4L, 8.1PP, 361CL, dipterocarp leaf litter (DP: 5.1N, 303L, 68.9PP, 271CL and tamarind leaf litter (TM: 11.6N, 190L, 27.7PP, 212CL were applied to soil annually to assess and predict soil larger fauna effects (LFE on decomposition based on the initial contents of the residue chemical constituents. Mass losses in all residues were not different under soil fauna inclusion and exclusion treatments during the early stage (up to week 4 after residue incorporation but became significantly higher under the inclusion than the exclusion treatments during the later stage (week 8 onwards. LFE were highest (2–51% under the resistant DP at most decomposition stages. During the early stage (weeks 1–4, both the initial contents of labile (N and CL and recalcitrant C, and recalcitrant C interaction with labile constituents of residues showed significant correlations (r = 0.64–0.90 with LFE. In the middle stage (week 16, LFE under resistant DP and TM had significant positive correlations with L, L + PP and L/CL. They were also affected by these quality parameters as shown by the multiple regression analysis. In the later stages (weeks 26–52, the L/CL ratio was the most prominent quality parameter affecting LFE. Keywords: Mesofauna and macrofauna, Microorganisms, Recalcitrant and labile compounds, Residue chemical composition, Tropical sandy soil

VT Data - Agriculturally Important Soil Units

Data.gov (United States)

Vermont Center for Geographic Information — (Link to Metadata) GeologicSoils_SOAG includes a pre-selected subset of SSURGO soil data depicting prime agricultural soils in Vermont. The SSURGO county coverages...

Linking N2O emissions from biochar-amended soil to the structure and function of the N-cycling microbial community

Science.gov (United States)

Harter, Johannes; Krause, Hans-Martin; Schuettler, Stefanie; Ruser, Reiner; Fromme, Markus; Scholten, Thomas; Kappler, Andreas; Behrens, Sebastian

2014-01-01

Nitrous oxide (N2O) contributes 8% to global greenhouse gas emissions. Agricultural sources represent about 60% of anthropogenic N2O emissions. Most agricultural N2O emissions are due to increased fertilizer application. A considerable fraction of nitrogen fertilizers are converted to N2O by microbiological processes (that is, nitrification and denitrification). Soil amended with biochar (charcoal created by pyrolysis of biomass) has been demonstrated to increase crop yield, improve soil quality and affect greenhouse gas emissions, for example, reduce N2O emissions. Despite several studies on variations in the general microbial community structure due to soil biochar amendment, hitherto the specific role of the nitrogen cycling microbial community in mitigating soil N2O emissions has not been subject of systematic investigation. We performed a microcosm study with a water-saturated soil amended with different amounts (0%, 2% and 10% (w/w)) of high-temperature biochar. By quantifying the abundance and activity of functional marker genes of microbial nitrogen fixation (nifH), nitrification (amoA) and denitrification (nirK, nirS and nosZ) using quantitative PCR we found that biochar addition enhanced microbial nitrous oxide reduction and increased the abundance of microorganisms capable of N2-fixation. Soil biochar amendment increased the relative gene and transcript copy numbers of the nosZ-encoded bacterial N2O reductase, suggesting a mechanistic link to the observed reduction in N2O emissions. Our findings contribute to a better understanding of the impact of biochar on the nitrogen cycling microbial community and the consequences of soil biochar amendment for microbial nitrogen transformation processes and N2O emissions from soil. PMID:24067258

Biodegradation of the cross-linked copolymer of acrylamide and potassium acrylate by soil bacteria.

Science.gov (United States)

Oksińska, Małgorzata P; Magnucka, Elżbieta G; Lejcuś, Krzysztof; Pietr, Stanisław J

2016-03-01

Chemical cross-linking and the high molecular weight of superabsorbent copolymers (SAPs) are the two main causes of their resistance to biodegradation. However, SAP particles are colonized by microorganisms. For the purposes of this study, the dry technical copolymer of acrylamide and potassium acrylate containing 5.28 % of unpolymerized monomers was wrapped in a geotextile and incubated in unsterile Haplic Luvisol soil as a water absorbing geocomposite. The highest number of soil bacteria that colonized the hydrated SAP and utilized it as the sole carbon and energy source was found after the first month of incubation in soil. It was equal to 7.21-7.49 log10 cfu g(-1) of water absorbed by the SAP and decreased by 1.35-1.61 log10 units within the next 8 months. During this time, the initial SAP water holding capacity of 1665.8 g has decreased by 24.40 %. Moreover, the 5 g of SAP dry mass has declined by 31.70 %. Two bacteria, Rhizobium radiobacter 28SG and Bacillus aryabhattai 31SG isolated from the watered SAP were found to be able to biodegrade this SAP in pure cultures. They destroyed 25.07 and 41.85 mg of 300 mg of the technical SAP during the 60-day growth in mineral Burk's salt medium, and biodegradation activity was equal to 2.95 and 6.72 μg of SAP μg(-1) of protein, respectively. B. aryabhattai 31SG and R. radiobacter 28SG were also able to degrade 9.99 and 29.70 mg of 82 mg of the ultra-pure SAP in synthetic root exudate medium during the 30-day growth, respectively.

Linking soil O2, CO2, and CH4 concentrations in a wetland soil

DEFF Research Database (Denmark)

Elberling, Bo; Jensen, Louise Askær; Jørgensen, Christian Juncher

2011-01-01

and CH4 were measured in the laboratory during flooding of soil columns using a combination of planar O2 optodes and membrane inlet mass spectrometry. Microsensors were used to assess apparent diffusivity under both field and laboratory conditions. Gas concentration profiles were analyzed...... plants tissue on soil gas dynamics and greenhouse gas emissions following marked changes in water level....

Linking Soil Physical Parameters Along a Density Gradient in a Loess-Soil Long-Term Experiment

DEFF Research Database (Denmark)

Eden, Marie; Møldrup, Per; Schjønning, Per

2012-01-01

It is important to understand the impact of texture and organic carbon (OC) on soil structure development. Only few studies investigated this for silt-dominated soils. In this study, soil physical properties were determined on samples from a controlled experiment (Static Fertilization Experiment...... hydraulic conductivity. The management resulted in a distinct gradient in OC. A bulk density gradient developed from differences in amount of clay not complexed with OC. This gradient in bulk density mainly affected content of pores larger than 3 [mu]m. The air-connected porosity measured by a pycnometer...

VT Data - NRCS Soil Survey Units

Data.gov (United States)

Vermont Center for Geographic Information — (Link to Metadata) This data set is a digital soil survey and generally is the most detailed level of soil geographic data developed by the National Cooperative Soil...

High Energy Moisture Characteristics: Linking Between Soil Physical Processes and Structure Stability

Science.gov (United States)

Water storage and flow in soils is usually complicated by the intricate nature of and changes in soil pore size distribution (PSD) due to modifications in soil structure following changes in agricultural management. The paper presents the Soil High Energy Moisture Characteristic (Soil-HEMC) method f...

Biological Soil Crust Web Site

Science.gov (United States)

www.soilcrust.org Crust 101 Advanced Gallery References CCERS site Links Biological Soil Crusts Textbook Corrections Level of Development Index Biological soil crusts are the community of organisms , mosses, liverworts and lichens. A Field Guide to Biological Soil Crusts of Western U.S. Drylands: Common

Regional conditions and land-use alter the potential contribution of soil arthropods to ecosystem services in grasslands

Directory of Open Access Journals (Sweden)

Klaus eBirkhofer

2016-01-01

Full Text Available We investigated the impact of regional conditions and land-use intensity on eight selected arthropod taxa of Mesostigmata (Parasitidae, Oribatida (3 species, Collembola (1 species, Chilopoda (2 species and Diplopoda (1 species sampled in differently managed permanent grasslands of three German study regions. By jointly analyzing changes in abundance and trophic behavior (measured as natural variation in 15N/14N and 13C/12C ratios we intended to develop a framework for evaluating the impact of local and regional conditions on the ecosystem services delivered by soil animals (mainly decomposition- and predation-related services. The investigated taxa could be assorted to three major groups: (1 numerical response only, (2 numerical and trophic response and (3 trophic response only. Since the combination of taxa assembled in the individual groups does not correspond to any of the conventional soil ecological classification systems, this grouping offers a new approach for analyzing soil communities. The complementing consideration of both the direction of the numerical response and the type of the trophic response (change of the basal food source vs. trophic level shift vs. variations in isotopic niches provided a differential insight into the effect of management and geographic differences on soil arthropods. It could be shown that the effect of land-use on the abundance of detritivorous microarthropods varies among regions, but does not induce any changes in feeding behavior. Our findings on Parasitidae indicate that carnivorous microarthropods exert substantial predation pressure on soil mesofauna and may be quite resistant to environmental changes due to high trophic flexibility. If conditions are favorable, centipedes may reach comparatively high densities in permanent grasslands and could be very important for controlling belowground pests. Concerning millipedes, isotopic signatures suggest that some species could exert a substantial disservice

Stimulation of soil microorganisms in pesticide-contaminated soil using organic materials

OpenAIRE

Ima Yudha Perwira; Kiwako S. Araki; Motoki Kubo; Dinesh Adhikari

2016-01-01

Agrochemicals such as pesticides have contributed to significant increases in crop yields; however, they can also be linked to adverse effects on human health and soil microorganisms. For efficient bioremediation of pesticides accumulated in agricultural fields, stimulation of microorganisms is necessary. In this study, we investigated the relationships between bacterial biomass and total carbon (TC) and total nitrogen (TN) in 427 agricultural soils. The soil bacterial biomass was generally p...

Two-dimensional NMR spectroscopy links structural moieties of soil organic matter to the temperature sensitivity of its decomposition

Science.gov (United States)

Soucemarianadin, Laure; Erhagen, Björn; Öquist, Mats; Nilsson, Mats; Schleucher, Jürgen

2015-04-01

be recognized. It was hence possible to follow the fate of specific structural moieties in soils. We observed differences between litter and soil samples, and were able to relate them to the decomposition of identifiable moieties. Using multivariate data analysis, we aimed at linking the detailed chemical fingerprints of SOM to turnover rates in a soil incubation experiment. With the multivariate models, we were able to relate signal patterns in the 2D spectra and intensities of identifiable molecular moieties to variability in the temperature response of organic matter decomposition, as assessed by Q10. In conclusion, the characterization of SOM composition at the molecular level by solution-state 2D NMR spectroscopy is highly promising; it offers unprecedented possibilities to link SOM molecular composition to ecosystem processes, and their responses to environmental changes.

High-Resolution Denitrification Kinetics in Pasture Soils Link N2O Emissions to pH, and Denitrification to C Mineralization.

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Md Sainur Samad

Full Text Available Denitrification in pasture soils is mediated by microbial and physicochemical processes leading to nitrogen loss through the emission of N2O and N2. It is known that N2O reduction to N2 is impaired by low soil pH yet controversy remains as inconsistent use of soil pH measurement methods by researchers, and differences in analytical methods between studies, undermine direct comparison of results. In addition, the link between denitrification and N2O emissions in response to carbon (C mineralization and pH in different pasture soils is still not well described. We hypothesized that potential denitrification rate and aerobic respiration rate would be positively associated with soils. This relationship was predicted to be more robust when a high resolution analysis is performed as opposed to a single time point comparison. We tested this by characterizing 13 different temperate pasture soils from northern and southern hemispheres sites (Ireland and New Zealand using a fully automated-high-resolution GC detection system that allowed us to detect a wide range of gas emissions simultaneously. We also compared the impact of using different extractants for determining pH on our conclusions. In all pH measurements, soil pH was strongly and negatively associated with both N2O production index (IN2O and N2O/(N2O+N2 product ratio. Furthermore, emission kinetics across all soils revealed that the denitrification rates under anoxic conditions (NO+N2O+N2 μmol N/h/vial were significantly associated with C mineralization (CO2 μmol/h/vial measured both under oxic (r2 = 0.62, p = 0.0015 and anoxic (r2 = 0.89, p<0.0001 conditions.

Design and Fabrication of a Soil Moisture Meter Using Thermal Conductivity Properties of Soil

Directory of Open Access Journals (Sweden)

Subir DAS

2011-09-01

Full Text Available Study of soil for agricultural purposes is one of the main focuses of research since the beginning of civilization as food related requirements is closely linked with the soil. The study of soil has generated an interest among the researchers for very similar other reasons including understanding of soil water dynamics, evolution of agricultural water stress and validation of soil moisture modeling. In this present work design of a soil moisture measurement meter using thermal conductivity properties of soil has been proposed and experimental results are reported.

Spatial distribution of the ground beatles populations in industrial cities (on the example of Nikopol

Directory of Open Access Journals (Sweden)

V. V. Bolgarin

2010-04-01

Full Text Available The influence of abiotic factors on species of Amara, Ophonus, Harpalus in the urban environment has been studied. The features of the ground beetles distribution in the districts of Nikopol have been analysed. The influence of roadway on the vital fuctions of ground beetles has been cleared up. Quantitative data of Amara, Ophonus, Harpalus numbers in the town of Nikopol have been discussed. The advantage of natural factors over anthropogenic ones for the existence of soil mesofauna in industrial town has been established.

Soil moisture dynamics and smoldering combustion limits of pocosin soils in North Carolina, USA

Science.gov (United States)

James Reardon; Gary Curcio; Roberta Bartlette

2009-01-01

Smoldering combustion of wetland organic soils in the south-eastern USA is a serious management concern. Previous studies have reported smoldering was sensitive to a wide range of moisture contents, but studies of soil moisture dynamics and changing smoldering combustion potential in wetland communities are limited. Linking soil moisture measurements with estimates of...

Functional traits of soil invertebrates as indicators for exposure to soil disturbance

International Nuclear Information System (INIS)

Hedde, Mickaël; Oort, Folkert van; Lamy, Isabelle

2012-01-01

We tested a trait-based approach to link a soil disturbance to changes in invertebrate communities. Soils and macro-invertebrates were sampled in sandy soils contaminated by long-term wastewater irrigation, adding notably organic matter and trace metals (TM). We hypothesized that functional traits of invertebrates depict ways of exposure and that exposure routes relate to specific TM pools. Geophages and soft-body invertebrates were chosen to inform on exposure by ingestion or contact, respectively. Trait-based indices depicted more accurately effects of pollution than community density and diversity did. Exposure by ingestion had more deleterious effects than by contact. Both types of exposed invertebrates were influenced by TM, but geophages mainly responded to changes in soil organic matter contents. The trait-based approach requires to be applied in various conditions to uncorrelate specific TM impacts from those of other environmental factors. - Highlights: ► We linked pollution, exposure routes and impacts on soil invertebrates. ► Proportions of exposed animals accurately depicted pollution effects. ► Exposure by ingestion had more deleterious effects than exposure by contact. ► Geophages decline reflected changes in soil organic matter. ► Soft-body proportions were mainly influenced by TM pools. - A trait-based approach hierarchized impacts of soil pollution on soil invertebrate communities following ways of exposure

Development of a Multianalyte Enzyme-Linked Immunosorbent Assay for Permethrin and Aroclors and Its Implementation for Analysis of Soil/Sediment and House Dust ExtractsExtracts

Science.gov (United States)

Development of a multianalyte enzyme-linked immunosorbent assay (ELISA) for detection of permethrin and aroclors 1248 or 1254, and implementation of the assay for analysis of soil/sediment samples are described. The feasibility of using the multianalyte ELISA to monitor aroclors ...

Linking soil type and rainfall characteristics towards estimation of surface evaporative capacitance

Science.gov (United States)

Or, D.; Bickel, S.; Lehmann, P.

2017-12-01

Separation of evapotranspiration (ET) to evaporation (E) and transpiration (T) components for attribution of surface fluxes or for assessment of isotope fractionation in groundwater remains a challenge. Regional estimates of soil evaporation often rely on plant-based (Penman-Monteith) ET estimates where is E is obtained as a residual or a fraction of potential evaporation. We propose a novel method for estimating E from soil-specific properties, regional rainfall characteristics and considering concurrent internal drainage that shelters soil water from evaporation. A soil-dependent evaporative characteristic length defines a depth below which soil water cannot be pulled to the surface by capillarity; this depth determines the maximal soil evaporative capacitance (SEC). The SEC is recharged by rainfall and subsequently emptied by competition between drainage and surface evaporation (considering canopy interception evaporation). We show that E is strongly dependent on rainfall characteristics (mean annual, number of storms) and soil textural type, with up to 50% of rainfall lost to evaporation in loamy soil. The SEC concept applied to different soil types and climatic regions offers direct bounds on regional surface evaporation independent of plant-based parameterization or energy balance calculations.

A Conceptual Framework for Soil management and its effect on Soil Biodiversity in Organic and Low Input Farming

OpenAIRE

Koopmans, Dr. C.J.; Smeding, Dr. F.W.

2008-01-01

Learning how to manage beneficial soil biological processes may be a key step towards developing sustainable agricultural systems. We designed a conceptual framework linking soil management practices to important soil-life groups and soil fertility services like nutrient cycling, soil structure and disease suppression. We selected a necessary parameter set to gain insight between management, soil life and soil support services. The findings help to develop management practices that optimise y...

Linking hydraulic properties of fire-affected soils to infiltration and water repellency

Science.gov (United States)

Moody, John A.; Kinner, David A.; Úbeda, Xavier

2009-12-01

SummaryHeat from wildfires can produce a two-layer system composed of extremely dry soil covered by a layer of ash, which when subjected to rainfall, may produce extreme floods. To understand the soil physics controlling runoff for these initial conditions, we used a small, portable disk infiltrometer to measure two hydraulic properties: (1) near-saturated hydraulic conductivity, K f and (2) sorptivity, S( θ i), as a function of initial soil moisture content, θ i, ranging from extremely dry conditions ( θ i ash, reference soils, soils unaffected by fire, and fire-affected soils. Each has a different degrees of water repellency that influences K f and S( θ i). Values of K f ranged from 4.5 × 10 -3 to 53 × 10 -3 cm s -1 for ash; from 0.93 × 10 -3 to 130 × 10 -3 cm s -1 for reference soils; and from 0.86 × 10 -3 to 3.0 × 10 -3 cm s -1, for soil unaffected by fire, which had the lowest values of K f. Measurements indicated that S( θ i) could be represented by an empirical non-linear function of θ i with a sorptivity maximum of 0.18-0.20 cm s -0.5, between 0.03 and 0.08 cm 3 cm -3. This functional form differs from the monotonically decreasing non-linear functions often used to represent S( θ i) for rainfall-runoff modeling. The sorptivity maximum may represent the combined effects of gravity, capillarity, and adsorption in a transitional domain corresponding to extremely dry soil, and moreover, it may explain the observed non-linear behavior, and the critical soil-moisture threshold of water repellent soils. Laboratory measurements of K f and S( θ i) are the first for ash and fire-affected soil, but additional measurements are needed of these hydraulic properties for in situ fire-affected soils. They provide insight into water repellency behavior and infiltration under extremely dry conditions. Most importantly, they indicate how existing rainfall-runoff models can be modified to accommodate a possible two-layer system in extremely dry conditions. These

Sustainable Soil Water Management Systems

OpenAIRE

Basch, G.; Kassam, A.; Friedrich, T.; Santos, F.L.; Gubiani, P.I.; Calegari, A.; Reichert, J.M.; dos Santos, D.R.

2012-01-01

Soil quality and its management must be considered as key elements for an effective management of water resources, given that the hydrological cycle and land management are intimately linked (Bossio et al. 2007). Soil degradation has been described by Bossio et al. (2010) as the starting point of a negative cycle of soil-water relationships, creating a positive, self-accelerating feedback loop with important negative impacts on water cycling and water productivity. Therefore, sustainable soil...

Soil and public health: invisible bridges

Science.gov (United States)

Pachepsky, Yakov

2017-04-01

Public health institutions, as ancient as civilizations itself, are intrinsically connected with soils. The massive body of the empirical knowledge about this connection has been accumulated. Recently unraveling the underlying mechanisms of this link has begun, and many of them appear to have the microbiological origin. The impressive progress in understanding the nexus between soil and health has been achieved by experimentation with preserved soil microbial systems functioning along with the metagenomic characterization. The objective of this work is to present an overview of some recent onsets. In the food safety arena, survival of human pathogens in soils has been related to the degree of soil eutrophication and/or related structure of soil microbial communities. Soil microbial systems affect the affinity of plants to internalizing pathogenic organisms. Pharmaceutical arsenals benefit from using field soil environment for developing antibiotics. Enzyme production by soil bacteria is used as the signal source for drug activation. Sanitary functions of sols are dependent on soil microbial system workings. The healthy living can be enhanced by the human immune system training received from direct contact with soils. The hygiene hypothesis considers the microbial input due to exposure to soil as the essential ecosystem service. The invisible links between soil and public health result in large-scale consequences. Examples of concurrent degradation of soil and public health are worth scrutinizing. Public health records can provide valuable sources of 'soil-public health' interactions. It may be worthwhile to examine current assessments of soil health from the public health standpoint. Soil management can be an efficient instrument of public health control.

Habitat and Biodiversity: One out of five essential soil functions for agricultural soils

Science.gov (United States)

Trinsoutrot Gattin, Isabelle; Creamer, Rachel; van Leeuwen, Jeroen; Vrebos, Dirk; Gatti, Fabio; Bampa, Francesca; Schulte, Rogier; Rutgers, Michiel

2017-04-01

Current agricultural challenges require developing new agricultural systems that can optimize the ecological functioning of soils in order to limit the use of chemical inputs (i.e. disease suppression) and maintain a high organic matter content. This implies our ability to evaluate the effects of management practices on immediate performance objectives (i.e. fertility linked to nutrient cycling) but also in longer-term objective (i.e. C cycling and storage) in a variety of agro-climatic conditions. These issues demand the development of systemic approaches for understanding the determinants of soil functioning. In ecology, it is generally accepted that there are many positive relationships between soil biodiversity indicators and the functioning of ecosystems. Indeed, soil organisms and their interactions are essential drivers of ecosystem processes and impact the response, resilience and adaptability of ecosystems to environmental pressures. Thus, maintaining soil biodiversity is a condition for the sustainability of cropping systems. In this new context, the European project Landmark considers soil functions as a key to the improvement of agricultural land management towards sustainable development goals, amongst the five functions is soil biodiversity and habitat provisioning. We propose to present how we manage within this project to deal with this challenging objective at three spatial scales : field, landscape (regional) and European (policy). We aim to define a link between the physical, chemical and biological soil properties and "habitat & biodiversity" soil function in order to identify key indicators which modulate biodiversity. This will allow us to quantify and assess this soil function, in order to provide insight in win wins and tradeoffs in soil functions to enhance management practices which optimise the biodiversity in European agricultural systems.

Linking Soil Moisture Variation and Abundance of Plants to Geomorphic Processes: A Generalized Model for Erosion-Uplifting Landscapes

Science.gov (United States)

Ding, Junyan; Johnson, Edward A.; Martin, Yvonne E.

2018-03-01

The diffusive and advective erosion-created landscapes have similar structure (hillslopes and channels) across different scales regardless of variations in drivers and controls. The relative magnitude of diffusive erosion to advective erosion (D/K ratio) in a landscape development model controls hillslope length, shape, and drainage density, which regulate soil moisture variation, one of the critical resources of plants, through the contributing area (A) and local slope (S) represented by a topographic index (TI). Here we explore the theoretical relation between geomorphic processes, TI, and the abundance and distribution of plants. We derived an analytical model that expresses the TI with D, K, and A. This gives us the relation between soil moisture variation and geomorphic processes. Plant tolerance curves are used to link plant performance to soil moisture. Using the hypothetical tolerance curves of three plants, we show that the abundance and distribution of xeric, mesic, and hydric plants on the landscape are regulated by the D/K ratio. Where diffusive erosion is the major erosion process (large D/K ratio), mesic plants have higher abundance relative to xeric and hydric plants and the landscape has longer and convex-upward hillslope and low channel density. Increasing the dominance of advective erosion increases relative abundance of xeric and hydric plants dominance, and the landscape has short and concave hillslope and high channel density.

Soil macrofauna functional groups and their effects on soil structure, as related to agricultural management practices across agroecological zones of Sub-Saharan Africa

NARCIS (Netherlands)

Ayuke, F.O.

2010-01-01

This study aimed at understanding the effects of crop management practices on soil macrofauna and the links with soil aggregation and soil organic matter dynamics, which is key to the improvement of infertile or degrading soils in Sub-Sahara Africa. Soil macrofauna, especially earthworms and

Linking tephrochronology and soil characteristics in the Sila and Nebrodi Mountains, Italy

Science.gov (United States)

Raab, Gerald; Halpern, Dieter; Scarciglia, Fabio; Raimondi, Salvatore; de Castro Portes, Raquel; Norton, Kevin; Egli, Markus

2017-04-01

Mediterranean soils are an important key to understanding past volcanic events and landscape evolution. The influence and timing of Quaternary volcanic events on soils, however, remains still poorly understood in southern Italy. We used a multi-method approach to explore the origin and age of volcanic deposits (soils) in Sicily and Calabria. By comparing the geochemical signature of the soils with the chemical fingerprint of magmatic effusive rocks in southern Italy, we tried to identify the source material. It seems that the investigated soils on the Nebrodi (Sicily) and Sila (Calabria) mountains were both influenced by volcanic deposits having a high-K calc-alkaline series volcanic background. The Aeolian islands (Lipari and Vulcano) are the most likely sources of origin. Due to weathering processes of the volcanic sediments and the partial mixing with the underlying non-volcanic parent material, a direct relation with the potential source areas was not always straightforward. Immobile elements and their corresponding ratios (e.g. the Nb/Y vs Zr/Ti plot) or trace elements (Co, Th) and rare earth elements gave better hints of the origin of the deposits. Radiocarbon dating of the stable soil organic fraction (H2O2 resistant) indicated a minimum age of 8 - 10 ka of the Nebrodi and Sila soils. The chemical proxy of alteration (CPA) and weathering index according to Parker (WIP) were tested as proxies for an age estimate of the volcanic deposits and duration of soil formation. The soils and, subsequently, landscape are characterized by multiple volcanic depositional phases for the last 30 - 50 ka in the Sila mountains and about 70 ka in the Nebrodi mountains. We show that a multi-method approach (numerical dating, relative dating using weathering indices and the forensic procedure) enabled the identification of potential source areas, gave tentative age estimates of the ash deposits, duration of soil formation and, therefore, improved our understanding of volcanic

Assessment of soil ecosystem in degraded areas of vineyards after organic treatments

Science.gov (United States)

Landi, Silvia; D'Errico, Giada; Gagnarli, Elena; Simoni, Sauro; Goggioli, Donatella; Guidi, Silvia; D'Avino, Lorenzo; Lagomarsino, Alessandra; Valboa, Giuseppe; Castaldini, Maurizio; Elio Agnelli, Alessandro; Fantappiè, Maria; Lorenzetti, Romina; Priori, Simone; Costantini, Edoardo A. C.

2017-04-01

In Italian vineyards, it is quite common to have areas characterized by problems in vine health, grape production and quality, often caused by improper land preparation before vine plantation and/or management. Causes for soil malfunctioning can include reduced contribution of the soil fauna to the ecosystem services such as nutrient cycles and organic matter turnover. ReSolVe is a transnational and interdisciplinary project, supported by Core-Organic+ program, aimed at testing the effects of selective agronomic strategies for restoring optimal soil functionality in degraded areas within organic vineyard. For this purpose, the evaluation and biomonitoring of the abundance of soil mesofauna, nematodes and microarthropods, represents an efficient tool to characterize the effects of crop management on soil quality. Assessing enzyme activities involved in the main biogeochemical cycling of C, N, P and S can also provide indication of soil functions and health status. Italian experimental plots are situated in two commercial farms in Tuscany: i) Fontodi, Panzano in Chianti (FI), which has been managed organically for more than 20 years and ii) San Disdagio, Roccastrada (GR), under organic farming since 2014. In each farm, three plots (250 m2 each) in the degraded areas and three relative control plots in the non-degraded areas were selected. The different restoring strategies implemented in each area were: i) compost, produced on farm by manure + pruning residue + grass, ii) faba bean and winter barley green manure, iii) dry mulching after sowing with Trifolium squarrosum L. Each treated and control plot has been studied for soil nematodes, microarthropods, enzymatic activity, and organic matter turnover using tea-bag index, as well as total organic carbon (TOC) and total nitrogen (TN). Soil sampling was carried out to 0-30 cm depth for TOC, TN, enzymes and nematodes and to 10 cm for microarthropods. Tea-bag index was determined following the Keuskamp et al. method

Soil Microbiology, Ecology, and Biochemistry

Science.gov (United States)

The 4th edition of Soil Microbiology, Ecology, and Biochemistry Edited by Eldor Paul continues in the vein of the 3rd edition by providing an excellent, broad-reaching introduction to soil biology. The new edition improves on the previous by providing extensive supplementary materials, links to outs...

VT Data - Onsite Sewage Disposal Soil Ratings

Data.gov (United States)

Vermont Center for Geographic Information — (Link to Metadata) ONSITE is a pre-selected subset of SSURGO certified soil data depicting onsite sewage disposal ratings of Vermont soils. The NRCS Top20 table was...

Localized enrichment of polycyclic aromatic hydrocarbons in soil, spruce needles, and lake sediments linked to in-situ bitumen extraction near Cold Lake, Alberta

International Nuclear Information System (INIS)

Korosi, J.B.; Irvine, G.; Skierszkan, E.K.; Doyle, J.R.; Kimpe, L.E.; Janvier, J.; Blais, J.M.

2013-01-01

The extraction of bitumen from the Alberta oil sands using in-situ technologies is expanding at a rapid rate; however, investigations into the environmental impacts of oil sands development have focused on surface mining in the Athabasca region. We measured polycyclic aromatic hydrocarbons (PAH) in soils, spruce needles, and lake sediment cores in the Cold Lake oil sands region to provide a historical and spatial perspective on PAH contamination related to in-situ extraction activities. A pronounced increase in PAH concentrations was recorded in one of two study lakes (Hilda Lake) corresponding to the onset of commercial bitumen production in ∼1985. Distance from extraction rigs was not an important predictor of PAH concentrations in soils, although two samples located near installations were elevated in alkyl PAHs. Evidence of localized PAH contamination in Hilda Lake and two soil samples suggests that continued environmental monitoring is justified to assess PAH contamination as development intensifies. -- Highlights: •In-situ bitumen extraction linked to rise in alkyl PAHs in one of two study lakes. •Alkyl PAHs elevated in two soil samples. •PAH contamination likely related to effluent sources, not atmospheric deposition. -- PAHs in sediments and soils were generally low in areas adjacent to in-situ bitumen extraction rigs in the Cold Lake Alberta oil sands, but evidence of localized contamination at some sites was evident

Stimulation of soil microorganisms in pesticide-contaminated soil using organic materials

Directory of Open Access Journals (Sweden)

Ima Yudha Perwira

2016-08-01

Full Text Available Agrochemicals such as pesticides have contributed to significant increases in crop yields; however, they can also be linked to adverse effects on human health and soil microorganisms. For efficient bioremediation of pesticides accumulated in agricultural fields, stimulation of microorganisms is necessary. In this study, we investigated the relationships between bacterial biomass and total carbon (TC and total nitrogen (TN in 427 agricultural soils. The soil bacterial biomass was generally positively correlated with TC and TN contents in the soil, but some soils had a low bacterial biomass despite containing high amounts of TC and TN. Soils of two fields (fields A and B with low bacterial biomass but high TC and TN contents were investigated. Long-term pesticide use (dichloropropane-dichloropropene and fosthiazate in field A and chloropicrin in field B appeared to have contributed to the low bacterial biomass observed in these soils. Soil from field A was treated with different organic materials and incubated for 1 month under laboratory conditions. The bacterial biomass in field A soil was enhanced in treatments containing organic materials rich in TN. Application of organic materials stimulated the growth of microorganisms with the potential to bioremediate pesticide-polluted soils.

Moditored unsaturated soil transport processes as a support for large scale soil and water management

Science.gov (United States)

Vanclooster, Marnik

2010-05-01

The current societal demand for sustainable soil and water management is very large. The drivers of global and climate change exert many pressures on the soil and water ecosystems, endangering appropriate ecosystem functioning. The unsaturated soil transport processes play a key role in soil-water system functioning as it controls the fluxes of water and nutrients from the soil to plants (the pedo-biosphere link), the infiltration flux of precipitated water to groundwater and the evaporative flux, and hence the feed back from the soil to the climate system. Yet, unsaturated soil transport processes are difficult to quantify since they are affected by huge variability of the governing properties at different space-time scales and the intrinsic non-linearity of the transport processes. The incompatibility of the scales between the scale at which processes reasonably can be characterized, the scale at which the theoretical process correctly can be described and the scale at which the soil and water system need to be managed, calls for further development of scaling procedures in unsaturated zone science. It also calls for a better integration of theoretical and modelling approaches to elucidate transport processes at the appropriate scales, compatible with the sustainable soil and water management objective. Moditoring science, i.e the interdisciplinary research domain where modelling and monitoring science are linked, is currently evolving significantly in the unsaturated zone hydrology area. In this presentation, a review of current moditoring strategies/techniques will be given and illustrated for solving large scale soil and water management problems. This will also allow identifying research needs in the interdisciplinary domain of modelling and monitoring and to improve the integration of unsaturated zone science in solving soil and water management issues. A focus will be given on examples of large scale soil and water management problems in Europe.

Soil properties linked to Phytophthora cinnamomi presence and oak decline in Iberian dehesas

Science.gov (United States)

Moreno, G.; Vivas, M.; Pérez, A.; Cubera, E.; Madeira, M.; Solla, A.

2009-04-01

Dehesas cover about 3,100,000 ha in the Iberian Peninsula, and support an outstanding diversity of wildlife and flora endemisms. These open woodlands provide Spain and Portugal inhabitants with a high-quality food, derived from animal production, sustain rural population, and act as retardants of soil erosion and desertification, which are considered primary environmental concerns in the Mediterranean basin. Dehesas are considered examples of sustainable use, though in the last few decades intensive land use, imposed by a concomitant change in the technological and socio-economic conditions, and common agricultural policies threat their conservation. Soil compaction and erosion, oak regeneration failure, dieback of old-ageing stands, and loose of biodiversity are some of the most common threats. At the same time, a severe decline of Quercus ilex (Holm oak) has been reported since the 1990s in the southern Iberian Peninsula, and more recently in France, Italy, and Morocco. In the Iberian Peninsula, the decline has been mostly observed in dehesas, where a combination of factors, possibly acting in synergy, have been put forward to explain the disease. Severe drought episodes, flooding, and rapid fluctuations in soil water content have been reported as predisposing factors favoring tree invasion by bark borer insects and/or pathogenic fungi. It is mostly ignored to what extent decline is a natural or a man-induced process, and if it is associated to either basic, management-related soil properties, or both. To bring insight to this problem, extensive and integrative comparisons of some soil properties related to hydromorphism were initiated, comprising pairs of adjacent non-symptomatic and symptomatic Q. ilex trees. In 2008, 48 dehesa stands from western Spain (Cáceres), half of them located along stream banks and the other half located in slopes, were intensively studied. In each stand, soil and root samples were taken under 3 non-symptomatic (healthy) and 3

Microbial links and element flows in nested detrital food-webs.

NARCIS (Netherlands)

Pokarzhevskii, A.D.; van Straalen, N.M.; Zaboev, D.P.; Zaitsev, A.S.

2003-01-01

Microbial links are obligate in any food chain in soil, because detritivorous animals derive essential amino acids and other resources from microorganisms. To degrade recalcitrant substrates such as cellulose, soil animals do not produce their own cellulase, but they use cellulases derived from gut

THE POTENTIAL OF γ-RAY SPECTROSCOPY FOR SOIL PROXIMAL SURVEY IN CLAYEY SOILS

Directory of Open Access Journals (Sweden)

Simone Priori

2014-01-01

Full Text Available Gamma-ray spectroscopy surveys the intensity and distribution of γ-rays emitted from radionuclides of soils and bedrocks. The most important radionuclides of soils and rocks are: 40K, 232Th, 238U and 137Cs, the latter due to Chernobyl burst or radioactive pollution. Distribution and quantity of these radionuclides into the soil is strictly linked to parent material mineralogy and soil cation exchange capacity. The aim of this work is to show the makings of γ-ray spectroscopy proximal survey within experimental fields with clayey soils in western Sicily.The γ-ray spectrometer used for the fieldwork was “The Mole”, made by “The Soil Company”, “Medusa system” and the University of Groningen, from The Netherlands. During the survey of eight experimental fields, 55 soil samples were collected for laboratory analysis of particle size distribution, calcium carbonate, organic carbon and total nitrogen content. The results of the work showed the statistical correlations between soil features and γ-ray data. 

Linking Soil Microbial Ecology to Ecosystem Functioning in Integrated Crop-Livestock Systems

Science.gov (United States)

Enhanced soil stability, nutrient cycling and C sequestration potential are important ecosystem functions driven by soil microbial processes and are directly influenced by agricultural management. Integrated crop-livestock agroecosystems (ICL) can enhance these functions via high-residue returning c...

The Soil Mobilome

DEFF Research Database (Denmark)

Luo, Wenting

Soil is considered a reservoir of diverse bacterial cellular functions, of which resistance mechanisms towards biological antimicrobial agents are of substantial interest to us. Previous findings report that the long-term accumulation of copper in an agricultural soil significantly affects......-selected for among natural bacterial populations. One possible explanation is the horizontal transfer of resistance genes among soil bacteria mediated by mobile genetic elements, such as plasmids, integrons, transposons and bacteriophages, of which copper and antibiotic resistance genes can be linked on the same...... mobile elements. To test this hypothesis, we collected non-polluted and CuSO4- contaminated soil samples and attempted to describe the co-selection of plasmid-encoded copper and antimicrobial resistance via both an endogenous plasmid isolation approach as well as a plasmid metagenomic approach...

Monitor Soil Degradation or Triage for Soil Security? An Australian Challenge

Directory of Open Access Journals (Sweden)

Andrea Koch

2015-04-01

Full Text Available The Australian National Soil Research, Development and Extension Strategy identifies soil security as a foundation for the current and future productivity and profitability of Australian agriculture. Current agricultural production is attenuated by soil degradation. Future production is highly dependent on the condition of Australian soils. Soil degradation in Australia is dominated in its areal extent by soil erosion. We reiterate the use of soil erosion as a reliable indicator of soil condition/quality and a practical measure of soil degradation. We describe three key phases of soil degradation since European settlement, and show a clear link between inappropriate agricultural practices and the resultant soil degradation. We demonstrate that modern agricultural practices have had a marked effect on reducing erosion. Current advances in agricultural soil management could lead to further stabilization and slowing of soil degradation in addition to improving productivity. However, policy complacency towards soil degradation, combined with future climate projections of increased rainfall intensity but decreased volumes, warmer temperatures and increased time in drought may once again accelerate soil degradation and susceptibility to erosion and thus limit the ability of agriculture to advance without further improving soil management practices. Monitoring soil degradation may indicate land degradation, but we contend that monitoring will not lead to soil security. We propose the adoption of a triaging approach to soil degradation using the soil security framework, to prioritise treatment plans that engage science and agriculture to develop practices that simultaneously increase productivity and improve soil condition. This will provide a public policy platform for efficient allocation of public and private resources to secure Australia’s soil resource.

Impacts of organic and inorganic fertilizers on nitrification in a cold climate soil are linked to the bacterial ammonia oxidizer community.

Science.gov (United States)

Fan, Fenliang; Yang, Qianbao; Li, Zhaojun; Wei, Dan; Cui, Xi'an; Liang, Yongchao

2011-11-01

The microbiology underpinning soil nitrogen cycling in northeast China remains poorly understood. These agricultural systems are typified by widely contrasting temperature, ranging from -40 to 38°C. In a long-term site in this region, the impacts of mineral and organic fertilizer amendments on potential nitrification rate (PNR) were determined. PNR was found to be suppressed by long-term mineral fertilizer treatment but enhanced by manure treatment. The abundance and structure of ammonia-oxidizing bacterial (AOB) and archaeal (AOA) communities were assessed using quantitative polymerase chain reaction and denaturing gradient gel electrophoresis techniques. The abundance of AOA was reduced by all fertilizer treatments, while the opposite response was measured for AOB, leading to a six- to 60-fold reduction in AOA/AOB ratio. The community structure of AOA exhibited little variation across fertilization treatments, whereas the structure of the AOB community was highly responsive. PNR was correlated with community structure of AOB rather than that of AOA. Variation in the community structure of AOB was linked to soil pH, total carbon, and nitrogen contents induced by different long-term fertilization regimes. The results suggest that manure amendment establishes conditions which select for an AOB community type which recovers mineral fertilizer-suppressed soil nitrification.

On the value of soil biodiversity and ecosystem services

NARCIS (Netherlands)

Pascual, U.; Termansen, M.; Hedlund, K.; Brussaard, L.; Faber, J.H.; Foudi, S.; Lemanceau, P.; Liv-Jørgensen, S.

2015-01-01

This paper provides a framework to understand the source of the economic value of soil biodiversity and soil ecosystem services and maps out the pathways of such values. We clarify the link between components of the economic value of soil biodiversity and their associated services of particular

Linking soil moisture balance and source-responsive models to estimate diffuse and preferential components of groundwater recharge

Science.gov (United States)

Cuthbert, M.O.; Mackay, R.; Nimmo, J.R.

2012-01-01

Results are presented of a detailed study into the vadose zone and shallow water table hydrodynamics of a field site in Shropshire, UK. A conceptual model is developed and tested using a range of numerical models, including a modified soil moisture balance model (SMBM) for estimating groundwater recharge in the presence of both diffuse and preferential flow components. Tensiometry reveals that the loamy sand topsoil wets up via macropore flow and subsequent redistribution of moisture into the soil matrix. Recharge does not occur until near-positive pressures are achieved at the top of the sandy glaciofluvial outwash material that underlies the topsoil, about 1 m above the water table. Once this occurs, very rapid water table rises follow. This threshold behaviour is attributed to the vertical discontinuity in the macropore system due to seasonal ploughing of the topsoil, and a lower permeability plough/iron pan restricting matrix flow between the topsoil and the lower outwash deposits. Although the wetting process in the topsoil is complex, a SMBM is shown to be effective in predicting the initiation of preferential flow from the base of the topsoil into the lower outwash horizon. The rapidity of the response at the water table and a water table rise during the summer period while flow gradients in the unsaturated profile were upward suggest that preferential flow is also occurring within the outwash deposits below the topsoil. A variation of the source-responsive model proposed by Nimmo (2010) is shown to reproduce the observed water table dynamics well in the lower outwash horizon when linked to a SMBM that quantifies the potential recharge from the topsoil. The results reveal new insights into preferential flow processes in cultivated soils and provide a useful and practical approach to accounting for preferential flow in studies of groundwater recharge estimation.

Linking soil moisture balance and source-responsive models to estimate diffuse and preferential components of groundwater recharge

Directory of Open Access Journals (Sweden)

M. O. Cuthbert

2013-03-01

Full Text Available Results are presented of a detailed study into the vadose zone and shallow water table hydrodynamics of a field site in Shropshire, UK. A conceptual model is presented and tested using a range of numerical models, including a modified soil moisture balance model (SMBM for estimating groundwater recharge in the presence of both diffuse and preferential flow components. Tensiometry reveals that the loamy sand topsoil wets up via preferential flow and subsequent redistribution of moisture into the soil matrix. Recharge does not occur until near-positive pressures are achieved at the top of the sandy glaciofluvial outwash material that underlies the topsoil, about 1 m above the water table. Once this occurs, very rapid water table rises follow. This threshold behaviour is attributed to the vertical discontinuity in preferential flow pathways due to seasonal ploughing of the topsoil and to a lower permeability plough/iron pan restricting matrix flow between the topsoil and the lower outwash deposits. Although the wetting process in the topsoil is complex, a SMBM is shown to be effective in predicting the initiation of preferential flow from the base of the topsoil into the lower outwash horizon. The rapidity of the response at the water table and a water table rise during the summer period while flow gradients in the unsaturated profile were upward suggest that preferential flow is also occurring within the outwash deposits below the topsoil. A variation of the source-responsive model proposed by Nimmo (2010 is shown to reproduce the observed water table dynamics well in the lower outwash horizon when linked to a SMBM that quantifies the potential recharge from the topsoil. The results reveal new insights into preferential flow processes in cultivated soils and provide a useful and practical approach to accounting for preferential flow in studies of groundwater recharge estimation.

European Atlas of Soil Biodiversity

DEFF Research Database (Denmark)

Krogh (contributor), Paul Henning

Soil is one of the fundamental components for supporting life on Earth. Most ecosystem processes and global functions that occur within soil are driven by living organisms that, in turn, sustain life above ground. However, despite the fact that soils are home to a quarter of all living species on...... Biodiversity is an essential reference to the many and varied aspects of soil. The overall goal of this work is to convey the fundamental necessity to safeguard soil biodiversity in order to guarantee life on this planet.......Soil is one of the fundamental components for supporting life on Earth. Most ecosystem processes and global functions that occur within soil are driven by living organisms that, in turn, sustain life above ground. However, despite the fact that soils are home to a quarter of all living species...... on Earth, life within the soil is often hidden away and suffers by being 'out of sight and out of mind'. What kind of life is there in soil? What do we mean by soil biodiversity? What is special about soil biology? How do our activities affect soil ecosystems? What are the links between soil biota...

Soil carbon estimation from eucalyptus grandis using canopy spectra

African Journals Online (AJOL)

Mapping soil fertility parameters, such as soil carbon (C), is fundamentally important for forest management and research related to forest growth and climate change. This study seeks to establish the link between Eucalyptus grandis canopy spectra and soil carbon using raw and continuum-removed spectra. Canopy-level ...

A process-based framework for soil ecosystem services study and management.

Science.gov (United States)

Su, Changhong; Liu, Huifang; Wang, Shuai

2018-06-15

Soil provides various indispensable ecosystem services for human society. Soil's complex structure and property makes the soil ecological processes complicated and brings about tough challenges for soil ecosystem services study. Most of the current frameworks on soil services focus exclusively on services per se, neglecting the links and underlying ecological mechanisms. This article put forward a framework on soil services by stressing the underlying soil mechanisms and processes, which includes: 1) analyzing soil natural capital stock based on soil structure and property, 2) disentangling the underlying complex links and soil processes, 3) soil services valuation based on field investigation and spatial explicit models, and 4) enacting soil management strategy based on soil services and their driving factors. By application of this framework, we assessed the soil services of sediment retention, water yield, and grain production in the Upper-reach Fenhe Watershed. Based on the ecosystem services and human driving factors, the whole watershed was clustered into five groups: 1) municipal area, 2) typical coal mining area, 3) traditional farming area, 4) unsustainable urbanizing area, and 5) ecological conservation area. Management strategies on soils were made according to the clustering based soil services and human activities. Copyright © 2018 Elsevier B.V. All rights reserved.

The significance of soils and soil science towards realization of the United Nations Sustainable Development Goals

Science.gov (United States)

Keesstra, Saskia D.; Bouma, Johan; Wallinga, Jakob; Tittonell, Pablo; Smith, Pete; Cerdà, Artemi; Montanarella, Luca; Quinton, John N.; Pachepsky, Yakov; van der Putten, Wim H.; Bardgett, Richard D.; Moolenaar, Simon; Mol, Gerben; Jansen, Boris; Fresco, Louise O.

2016-04-01

In this forum paper we discuss how soil scientists can help to reach the recently adopted UN Sustainable Development Goals (SDGs) in the most effective manner. Soil science, as a land-related discipline, has important links to several of the SDGs, which are demonstrated through the functions of soils and the ecosystem services that are linked to those functions (see graphical abstract in the Supplement). We explore and discuss how soil scientists can rise to the challenge both internally, in terms of our procedures and practices, and externally, in terms of our relations with colleague scientists in other disciplines, diverse groups of stakeholders and the policy arena. To meet these goals we recommend the following steps to be taken by the soil science community as a whole: (i) embrace the UN SDGs, as they provide a platform that allows soil science to demonstrate its relevance for realizing a sustainable society by 2030; (ii) show the specific value of soil science: research should explicitly show how using modern soil information can improve the results of inter- and transdisciplinary studies on SDGs related to food security, water scarcity, climate change, biodiversity loss and health threats; (iii) take leadership in overarching system analysis of ecosystems, as soils and soil scientists have an integrated nature and this places soil scientists in a unique position; (iii) raise awareness of soil organic matter as a key attribute of soils to illustrate its importance for soil functions and ecosystem services; (iv) improve the transfer of knowledge through knowledge brokers with a soil background; (v) start at the basis: educational programmes are needed at all levels, starting in primary schools, and emphasizing practical, down-to-earth examples; (vi) facilitate communication with the policy arena by framing research in terms that resonate with politicians in terms of the policy cycle or by considering drivers, pressures and responses affecting impacts of land

Relationships at the aboveground-belowground interface: plants, soil biota and soil processes

NARCIS (Netherlands)

Porazinska, D.L.; Bardgett, R.D.; Postma-Blaauw, M.B.; Hunt, H.W.; Parsons, A.N.; Seastedt, T.R.; Wall, D.M.

2003-01-01

Interactions at the aboveground-below ground interface provide important feedbacks that regulate ecosystem processes. Organisms within soil food webs are involved in processes of decomposition and nutrient mineralization, and their abundance and activity have been linked to plant ecophysiological

A Brief History of Soils and Human Health Studies

Science.gov (United States)

Brevik, Eric C.; Sauer, Thomas J.

2013-04-01

The idea that there are links between soils and human health is an ancient one. The Bible depicts Moses as understanding that fertile soil was essential to the well-being of his people in approximately 1400 B.C. as they entered Canaan, and in 400 B.C. Hippocrates provided a list of things that should be considered in a proper medical evaluation, including the ground. Moving into the 18th and 19th Centuries, some North American farmers have been documented as recognizing a link between soils and human vitality. However, the recognition of links between soils and human health by these early people was based on casual observations leading to logical conclusions rather than scientific investigation. In the 1900s the idea that soils influence human health gained considerable traction. At least three chapters in the 1938 USDA Yearbook of Agriculture included recognition of the importance of soil as the origin of many of the mineral elements necessary for human health and in the 1957 USDA Yearbook of Agriculture scientists realized that soils were not only important in the supply of essential nutrients, but that they could also supply toxic levels of elements to the human diet. The U.S. Department of Agriculture established the Plant, Soil and Nutrition Research Unit (PSNRU) on the Cornell University campus in 1940 with a mission to conduct research at the interface of human nutrition and agriculture to improve the nutritional quality and health-promoting properties of food crops. A major human health breakthrough in 1940 was the isolation of antibiotic compounds from soil organisms by the research group at Rutgers University lead by Selman Waksman. Soil microorganisms create antibiotic compounds in an effort to gain a competitive advantage in the soil ecosystem. Humans have been able to isolate those compounds and use them advantageously in the fight against bacterial infections. Waksman was awarded the Nobel Prize in Physiology or Medicine in 1952, the only soil

Prediction of the soil water retention curve for structured soil from saturation to oven-dryness

DEFF Research Database (Denmark)

Karup, Dan; Møldrup, Per; Tuller, Markus

2017-01-01

. Independently measured SWRCs for 171 undisturbed soil samples with organic matter contents that ranged from 3 to 14% were used for model validation. The results indicate that consideration of the silt and organic matter fractions, in addition to the clay fraction, improved predictions for the dry-end SWRC......The soil water retention curve (SWRC) is the most fundamental soil hydraulic function required for modelling soil–plant–atmospheric water flow and transport processes. The SWRC is intimately linked to the distribution of the size of pores, the composition of the solid phase and the soil specific...... surface area. Detailed measurement of the SWRC is impractical in many cases because of the excessively long equilibration times inherent to most standard methods, especially for fine textured soil. Consequently, it is more efficient to predict the SWRCbased on easy-to-measure basic soil properties...

Linking annual N2O emission in organic soils to mineral nitrogen input as estimated by heterotrophic respiration and soil C/N ratio.

Science.gov (United States)

Mu, Zhijian; Huang, Aiying; Ni, Jiupai; Xie, Deti

2014-01-01

Organic soils are an important source of N2O, but global estimates of these fluxes remain uncertain because measurements are sparse. We tested the hypothesis that N2O fluxes can be predicted from estimates of mineral nitrogen input, calculated from readily-available measurements of CO2 flux and soil C/N ratio. From studies of organic soils throughout the world, we compiled a data set of annual CO2 and N2O fluxes which were measured concurrently. The input of soil mineral nitrogen in these studies was estimated from applied fertilizer nitrogen and organic nitrogen mineralization. The latter was calculated by dividing the rate of soil heterotrophic respiration by soil C/N ratio. This index of mineral nitrogen input explained up to 69% of the overall variability of N2O fluxes, whereas CO2 flux or soil C/N ratio alone explained only 49% and 36% of the variability, respectively. Including water table level in the model, along with mineral nitrogen input, further improved the model with the explanatory proportion of variability in N2O flux increasing to 75%. Unlike grassland or cropland soils, forest soils were evidently nitrogen-limited, so water table level had no significant effect on N2O flux. Our proposed approach, which uses the product of soil-derived CO2 flux and the inverse of soil C/N ratio as a proxy for nitrogen mineralization, shows promise for estimating regional or global N2O fluxes from organic soils, although some further enhancements may be warranted.

The Italian contribution to the World Soils Book Series: The Soils of Italy

Science.gov (United States)

Costantini, Edoardo; Dazzi, Carmelo

2015-04-01

Passing to the age of "Anthropocene", man has forgotten the ancient bond that ties him to the soil, and turning from "homo sapiens" to "homo technologicus" he has stopped considering how much his well-being and the quality of life on Earth are fundamentally linked to the quality of soils. Yet today, as never before, maintaining the quality of soils is of paramount relevance for the sustainable development of humanity. Unfortunately, as soils are a crypto-resource, not many lay-people recognize its importance in the biosphere equilibrium and, unfortunately, seldom consider it among the environmental resources that must be protected! To fill such a gap in knowledge, the Springer editor, under the leading of professor Alfred Hartemink, has published the World Soils Book Series, whose aim is to spread the knowledge on the soils in a particular country in a concise and highly reader-friendly way. The volume "The Soils of Italy" belongs to this international series of books. Its ambitious goals are to establish a broad base for the knowledge of the soils of Italy, and to give useful information on i) their characteristics, diffusion and fertility, ii) the main threats they are subjected, and iii) the future scenarios of relationships between soil sciences and the disciplines, which are not traditionally linked to the world of agriculture, such as urban development, medicine, economics, sociology, archaeology. In Italy there is about 75% of the global pedodiversity. A vast majority of the WRB reference soil groups (25 out of 32), as well as soil orders of Soil Taxonomy (10 out of 12) are represented in the main Italian soil typological units (STUs). More than a fourth of STUs belongs to Cambisols, more than a half to only four reference soil groups (Cambisols, Luvisols, Regosols, Phaeozems), and 88% to nine RSGs (the former plus Calcisols, Vertisols, Fluvisols, Leptosols, and Andosols), while the remaining 16 RSGs are represented in 12% of STUs. The clear skewness and

Quantifying the Interactions Between Soil Thermal Characteristics, Soil Physical Properties, Hydro-geomorphological Conditions and Vegetation Distribution in an Arctic Watershed

Science.gov (United States)

Dafflon, B.; Leger, E.; Robert, Y.; Ulrich, C.; Peterson, J. E.; Soom, F.; Biraud, S.; Tran, A. P.; Hubbard, S. S.

2017-12-01

Improving understanding of Arctic ecosystem functioning and parameterization of process-rich hydro-biogeochemical models require advances in quantifying ecosystem properties, from the bedrock to the top of the canopy. In Arctic regions having significant subsurface heterogeneity, understanding the link between soil physical properties (incl. fraction of soil constituents, bedrock depth, permafrost characteristics), thermal behavior, hydrological conditions and landscape properties is particularly challenging yet is critical for predicting the storage and flux of carbon in a changing climate. This study takes place in Seward Peninsula Watersheds near Nome AK and Council AK, which are characterized by an elevation gradient, shallow bedrock, and discontinuous permafrost. To characterize permafrost distribution where the top of permafrost cannot be easily identified with a tile probe (due to rocky soil and/or large thaw layer thickness), we developed a novel technique using vertically resolved thermistor probes to directly sense the temperature regime at multiple depths and locations. These measurements complement electrical imaging, seismic refraction and point-scale data for identification of the various thermal behavior and soil characteristics. Also, we evaluate linkages between the soil physical-thermal properties and the surface properties (hydrological conditions, geomorphic characteristics and vegetation distribution) using UAV-based aerial imaging. Data integration and analysis is supported by numerical approaches that simulate hydrological and thermal processes. Overall, this study enables the identification of watershed structure and the links between various subsurface and landscape properties in representative Arctic watersheds. Results show very distinct trends in vertically resolved soil temperature profiles and strong lateral variations over tens of meters that are linked to zones with various hydrological conditions, soil properties and vegetation

Soil Organic Carbon dynamics in agricultural soils of Veneto Region

Science.gov (United States)

Bampa, F. B.; Morari, F. M.; Hiederer, R. H.; Toth, G. T.; Giandon, P. G.; Vinci, I. V.; Montanarella, L. M.; Nocita, M.

2012-04-01

One of the eight soil threats expressed in the European Commission's Thematic Strategy for Soil Protection (COM (2006)231 final) it's the decline in Soil Organic Matter (SOM). His preservation is recognized as with the objective to ensure that the soils of Europe remain healthy and capable of supporting human activities and ecosystems. One of the key goals of the strategy is to maintain and improve Soil Organic Carbon (SOC) levels. As climate change is identified as a common element in many of the soil threats, the European Commission (EC) intends to assess the actual contribution of the soil protection to climate change mitigation and the effects of climate change on the possible depletion of SOM. A substantial proportion of European land is occupied by agriculture, and consequently plays a crucial role in maintaining natural resources. Organic carbon preservation and sequestration in the EU's agricultural soils could have some potential to mitigate the effects of climate change, particularly linked to preventing certain land use changes and maintaining SOC stocks. The objective of this study is to assess the SOC dynamics in agricultural soils (cropland and grassland) at regional scale, focusing on changes due to land use. A sub-objective would be the evaluation of the most used land management practices and their effect on SOC content. This assessment aims to determine the geographical distribution of the potential GHG mitigation options, focusing on hot spots in the EU, where mitigation actions would be particularly efficient and is linked with the on-going work in the JRC SOIL Action. The pilot area is Veneto Region. The data available are coming from different sources, timing and involve different variables as: soil texture, climate, soil disturbance, managements and nutrients. The first source of data is the LUCAS project (Land Use/Land Cover Area Frame statistical Survey). Started in 2001, the LUCAS project aims to monitor changes in land cover/use and

Soil Organic Matter Stability and Soil Carbon Storage with Changes in Land Use Intensity in Uganda

Science.gov (United States)

Tiemann, L. K.; Grandy, S.; Hartter, J.

2014-12-01

As the foundation of soil fertility, soil organic matter (SOM) formation and break-down is a critical factor of agroecosystem sustainability. In tropical systems where soils are quickly weathered, the link between SOM and soil fertility is particularly strong; however, the mechanisms controlling the stabilization and destabilization of SOM are not well characterized in tropical soils. In western Uganda, we collected soil samples under different levels of land use intensity including maize fields, banana plantations and inside an un-cultivated native tropical forest, Kibale National Park (KNP). To better understand the link between land use intensity and SOM stability we measured total soil C and N, and respiration rates during a 369 d soil incubation. In addition, we separated soils into particle size fractions, and mineral adsorbed SOM in the silt (2-50 μm ) and clay (fractions was dissociated, purified and chemically characterized via pyrolysis-GC/MS. Cultivated soil C and N have declined by 22 and 48%, respectively, in comparison to uncultivated KNP soils. Incubation data indicate that over the last decade, relatively accessible and labile soil organic carbon (SOC) pools have been depleted by 55-59% in cultivated soils. As a result of this depletion, the chemical composition of SOM has been altered such that clay and silt associated SOM differed significantly between agricultural fields and KNP. In particular, nitrogen containing compounds were in lower abundance in agricultural compared to KNP soils. This suggests that N depletion due to agriculture has advanced to pools of mineral associated organic N that are typically protected from break-down. In areas where land use intensity is relatively greater, increases in polysaccharides and lipids in maize fields compared to KNP indicate increases in microbial residues and decomposition by-products as microbes mine SOM for organic N. Chemical characterization of post-incubation SOM will help us better understand

Trichoderma Biofertilizer Links to Altered Soil Chemistry, Altered Microbial Communities, and Improved Grassland Biomass

Directory of Open Access Journals (Sweden)

Fengge Zhang

2018-04-01

Full Text Available In grasslands, forage and livestock production results in soil nutrient deficits as grasslands typically receive no nutrient inputs, leading to a loss of grassland biomass. The application of mature compost has been shown to effectively increase grassland nutrient availability. However, research on fertilization regime influence and potential microbial ecological regulation mechanisms are rarely conducted in grassland soil. We conducted a two-year experiment in meadow steppe grasslands, focusing on above- and belowground consequences of organic or Trichoderma biofertilizer applications and potential soil microbial ecological mechanisms underlying soil chemistry and microbial community responses. Grassland biomass significantly (p = 0.019 increased following amendment with 9,000 kg ha−1 of Trichoderma biofertilizer (composted cattle manure + inoculum compared with other assessed organic or biofertilizer rates, except for BOF3000 (fertilized with 3,000 kg ha−1 biofertilizer. This rate of Trichoderma biofertilizer treatment increased soil antifungal compounds that may suppress pathogenic fungi, potentially partially responsible for improved grassland biomass. Nonmetric multidimensional scaling (NMDS revealed soil chemistry and fungal communities were all separated by different fertilization regime. Trichoderma biofertilizer (9,000 kg ha−1 increased relative abundances of Archaeorhizomyces and Trichoderma while decreasing Ophiosphaerella. Trichoderma can improve grassland biomass, while Ophiosphaerella has the opposite effect as it may secrete metabolites causing grass necrosis. Correlations between soil properties and microbial genera showed plant-available phosphorus may influence grassland biomass by increasing Archaeorhizomyces and Trichoderma while reducing Ophiosphaerella. According to our structural equation modeling (SEM, Trichoderma abundance was the primary contributor to aboveground grassland biomass. Our results suggest Trichoderma

Trichoderma Biofertilizer Links to Altered Soil Chemistry, Altered Microbial Communities, and Improved Grassland Biomass.

Science.gov (United States)

Zhang, Fengge; Huo, Yunqian; Cobb, Adam B; Luo, Gongwen; Zhou, Jiqiong; Yang, Gaowen; Wilson, Gail W T; Zhang, Yingjun

2018-01-01

In grasslands, forage and livestock production results in soil nutrient deficits as grasslands typically receive no nutrient inputs, leading to a loss of grassland biomass. The application of mature compost has been shown to effectively increase grassland nutrient availability. However, research on fertilization regime influence and potential microbial ecological regulation mechanisms are rarely conducted in grassland soil. We conducted a two-year experiment in meadow steppe grasslands, focusing on above- and belowground consequences of organic or Trichoderma biofertilizer applications and potential soil microbial ecological mechanisms underlying soil chemistry and microbial community responses. Grassland biomass significantly ( p = 0.019) increased following amendment with 9,000 kg ha -1 of Trichoderma biofertilizer (composted cattle manure + inoculum) compared with other assessed organic or biofertilizer rates, except for BOF3000 (fertilized with 3,000 kg ha -1 biofertilizer). This rate of Trichoderma biofertilizer treatment increased soil antifungal compounds that may suppress pathogenic fungi, potentially partially responsible for improved grassland biomass. Nonmetric multidimensional scaling (NMDS) revealed soil chemistry and fungal communities were all separated by different fertilization regime. Trichoderma biofertilizer (9,000 kg ha -1 ) increased relative abundances of Archaeorhizomyces and Trichoderma while decreasing Ophiosphaerella . Trichoderma can improve grassland biomass, while Ophiosphaerella has the opposite effect as it may secrete metabolites causing grass necrosis. Correlations between soil properties and microbial genera showed plant-available phosphorus may influence grassland biomass by increasing Archaeorhizomyces and Trichoderma while reducing Ophiosphaerella . According to our structural equation modeling (SEM), Trichoderma abundance was the primary contributor to aboveground grassland biomass. Our results suggest Trichoderma

Root biomass and exudates link plant diversity with soil bacterial and fungal biomass

NARCIS (Netherlands)

Eisenhauer, Nico; Lanoue, Arnaud; Strecker, Tanja; Scheu, Stefan; Steinauer, Katja; Thakur, Madhav P.; Mommer, Liesje

2017-01-01

Plant diversity has been shown to determine the composition and functioning of soil biota. Although root-derived organic inputs are discussed as the main drivers of soil communities, experimental evidence is scarce. While there is some evidence that higher root biomass at high plant diversity

Physical soil architectural traits are functionally linked to carbon decomposition and bacterial diversity

Science.gov (United States)

Rabbi, S. M. F.; Daniel, H.; Lockwood, P. V.; MacDonald, C.; Pereg, L.; Tighe, M.; Wilson, B. R.; Young, I. M.

2016-09-01

Aggregates play a key role in protecting soil organic carbon (SOC) from microbial decomposition. The objectives of this study were to investigate the influence of pore geometry on the organic carbon decomposition rate and bacterial diversity in both macro- (250-2000 μm) and micro-aggregates (53-250 μm) using field samples. Four sites of contrasting land use on Alfisols (i.e. native pasture, crop/pasture rotation, woodland) were investigated. 3D Pore geometry of the micro-aggregates and macro-aggregates were examined by X-ray computed tomography (μCT). The occluded particulate organic carbon (oPOC) of aggregates was measured by size and density fractionation methods. Micro-aggregates had 54% less μCT observed porosity but 64% more oPOC compared with macro-aggregates. In addition, the pore connectivity in micro-aggregates was lower than macro-aggregates. Despite both lower μCT observed porosity and pore connectivity in micro-aggregates, the organic carbon decomposition rate constant (Ksoc) was similar in both aggregate size ranges. Structural equation modelling showed a strong positive relationship of the concentration of oPOC with bacterial diversity in aggregates. We use these findings to propose a conceptual model that illustrates the dynamic links between substrate, bacterial diversity, and pore geometry that suggests a structural explanation for differences in bacterial diversity across aggregate sizes.

An Overview of Soils and Human Health

Science.gov (United States)

Brevik, Eric C.

2013-04-01

Few people recognize the connection between soils and human health, even though soils are actually very important to health. Soils influence health through the nutrients taken up by plants and the animals that eat those plants, nutrients that are needed for adequate nutrition for growth and development. Soils can also act to harm human health in three major ways: i) toxic levels of substances or disease-causing organisms may enter the human food chain from the soil ii) humans can encounter pathogenic organisms through direct contact with the soil or inhaling dust from the soil, and iii) degraded soils produce nutrient-deficient foods leading to malnutrition. Soils have also been a major source of medicines. Therefore, soils form an integral link in the holistic view of human health. In this presentation, soils and their influence on human health are discussed from a broad perspective, including both direct influences of soils on health and indirect influences through things such as climate change, occupational exposure to soil amendments, and the role of soils in providing food security.

Ecological drivers of soil microbial diversity and soil biological networks in the Southern Hemisphere.

Science.gov (United States)

Delgado-Baquerizo, Manuel; Reith, Frank; Dennis, Paul G; Hamonts, Kelly; Powell, Jeff R; Young, Andrew; Singh, Brajesh K; Bissett, Andrew

2018-03-01

The ecological drivers of soil biodiversity in the Southern Hemisphere remain underexplored. Here, in a continental survey comprising 647 sites, across 58 degrees of latitude between tropical Australia and Antarctica, we evaluated the major ecological patterns in soil biodiversity and relative abundance of ecological clusters within a co-occurrence network of soil bacteria, archaea and eukaryotes. Six major ecological clusters (modules) of co-occurring soil taxa were identified. These clusters exhibited strong shifts in their relative abundances with increasing distance from the equator. Temperature was the major environmental driver of the relative abundance of ecological clusters when Australia and Antarctica are analyzed together. Temperature, aridity, soil properties and vegetation types were the major drivers of the relative abundance of different ecological clusters within Australia. Our data supports significant reductions in the diversity of bacteria, archaea and eukaryotes in Antarctica vs. Australia linked to strong reductions in temperature. However, we only detected small latitudinal variations in soil biodiversity within Australia. Different environmental drivers regulate the diversity of soil archaea (temperature and soil carbon), bacteria (aridity, vegetation attributes and pH) and eukaryotes (vegetation type and soil carbon) across Australia. Together, our findings provide new insights into the mechanisms driving soil biodiversity in the Southern Hemisphere. © 2018 by the Ecological Society of America.

Linking an economic model for European agriculture with a mechanistic model to estimate nitrogen and carbon losses from arable soils in Europe

Directory of Open Access Journals (Sweden)

A. Leip

2008-01-01

Full Text Available A comprehensive assessment of policy impact on greenhouse gas (GHG emissions from agricultural soils requires careful consideration of both socio-economic aspects and the environmental heterogeneity of the landscape. We developed a modelling framework that links the large-scale economic model for agriculture CAPRI (Common Agricultural Policy Regional Impact assessment with the biogeochemistry model DNDC (DeNitrification DeComposition to simulate GHG fluxes, carbon stock changes and the nitrogen budget of agricultural soils in Europe. The framework allows the ex-ante simulation of agricultural or agri-environmental policy impacts on a wide range of environmental problems such as climate change (GHG emissions, air pollution and groundwater pollution. Those environmental impacts can be analyzed in the context of economic and social indicators as calculated by the economic model. The methodology consists of four steps: (i definition of appropriate calculation units that can be considered as homogeneous in terms of economic behaviour and environmental response; (ii downscaling of regional agricultural statistics and farm management information from a CAPRI simulation run into the spatial calculation units; (iii designing environmental model scenarios and model runs; and finally (iv aggregating results for interpretation. We show the first results of the nitrogen budget in croplands in fourteen countries of the European Union and discuss possibilities to improve the detailed assessment of nitrogen and carbon fluxes from European arable soils.

Soil infiltration based on bp neural network and grey relational analysis

OpenAIRE

Juan,Wang; Pute,Wu; Xining,Zhao

2013-01-01

Soil infiltration is a key link of the natural water cycle process. Studies on soil permeability are conducive for water resources assessment and estimation, runoff regulation and management, soil erosion modeling, nonpoint and point source pollution of farmland, among other aspects. The unequal influence of rainfall duration, rainfall intensity, antecedent soil moisture, vegetation cover, vegetation type, and slope gradient on soil cumulative infiltration was studied under simulated rainfall...

Functional traits of soil invertebrates as indicators for exposure to soil disturbance.

Science.gov (United States)

Hedde, Mickaël; van Oort, Folkert; Lamy, Isabelle

2012-05-01

We tested a trait-based approach to link a soil disturbance to changes in invertebrate communities. Soils and macro-invertebrates were sampled in sandy soils contaminated by long-term wastewater irrigation, adding notably organic matter and trace metals (TM). We hypothesized that functional traits of invertebrates depict ways of exposure and that exposure routes relate to specific TM pools. Geophages and soft-body invertebrates were chosen to inform on exposure by ingestion or contact, respectively. Trait-based indices depicted more accurately effects of pollution than community density and diversity did. Exposure by ingestion had more deleterious effects than by contact. Both types of exposed invertebrates were influenced by TM, but geophages mainly responded to changes in soil organic matter contents. The trait-based approach requires to be applied in various conditions to uncorrelate specific TM impacts from those of other environmental factors. Copyright © 2012 Elsevier Ltd. All rights reserved.

Role of soil biology and soil functions in relation to land use intensity.

Science.gov (United States)

Bondi, Giulia; Wall, David; Bacher, Matthias; Emmet-Booth, Jeremy; Graça, Jessica; Marongiu, Irene; Creamer, Rachel

2017-04-01

The delivery of the ecosystem's functions is predominantly controlled by soil biology. The biology found in a gram of soil contains more than ten thousand individual species of bacteria and fungi (Torsvik et al., 1990). Understanding the role and the requirements of these organisms is essential for the protection and the sustainable use of soils. Soil biology represents the engine of all the processes occurring in the soil and it supports the ecosystem services such as: 1) nutrient mineralisation 2) plant production 3) water purification and regulation and 4) carbon cycling and storage. During the last years land management type and intensity have been identified as major drivers for microbial performance in soil. For this reason land management needs to be appropriately studied to understand the role of soil biology within this complex interplay of functions. We aimed to study whether and how land management drives soil biological processes and related functions. To reach this objective we built a land use intensity index (LUI) able to quantify the impact of the common farming practices carried out in Irish grassland soils. The LUI is derived from a detailed farmer questionnaire on grassland management practices at 38 farms distributed in the five major agro-climatic regions of Ireland defined by Holden and Brereton (2004). Soils were classified based on their drainage status according to the Irish Soil Information System by Creamer et al. (2014). This detailed questionnaire is then summarised into 3 management intensity components: (i) intensity of Fertilisation (Fi), (ii) frequency of Mowing (Mi) and (iii) intensity of Livestock Grazing (Gi). Sites were sampled to assess the impact of land management intensity on microbial community structure and enzyme behaviour in relation to nitrogen, phosphorus and carbon cycling. Preliminary results for enzymes linked to C and N cycles showed higher activity in relation to low grazing pressure (low Gi). Enzymes linked to P

Preliminary results of a study on the soil mesofauna in disturbed spruce forest stands near Čertovo and Plešné Lakes in the Bohemian Forest (Czech Republic)

Czech Academy of Sciences Publication Activity Database

Čuchta, Peter; Starý, Josef

2015-01-01

Roč. 79, č. 3 (2015), s. 161-167 ISSN 1211-376X R&D Projects: GA ČR GAP504/12/1218 Institutional support: RVO:60077344 Keywords : windthrow * bark beetle * soil arthropod s * Bohemian Forest Subject RIV: EH - Ecology, Behaviour

LORICA - A new model for linking landscape and soil profile evolution: Development and sensitivity analysis

NARCIS (Netherlands)

Temme, A.J.A.M.; Vanwalleghem, T.

2016-01-01

Soils and landscapes evolve in tandem. Landscape position is a strong determinant of vertical soil development, which has often been formalized in the catena concept. At the same time, soil properties are strong determinants of geomorphic processes such as overland erosion, landsliding and creep. We

Case studies: Soil mapping using multiple methods

Science.gov (United States)

Petersen, Hauke; Wunderlich, Tina; Hagrey, Said A. Al; Rabbel, Wolfgang; Stümpel, Harald

2010-05-01

application of geophysical methods, e.g. GPR on wet loessy soils will result in a high attenuation of signals. Furthermore, with this knowledge we support the development of geophysical pedo-transfer-functions, i.e. the link between geophysical to soil parameters, which is active researched in another work package of the iSOIL project. Acknowledgement: iSOIL-Interactions between soil related sciences - Linking geophysics, soil science and digital soil mapping is a Collaborative Project (Grant Agreement number 211386) co-funded by the Research DG of the European Commission within the RTD activities of the FP7 Thematic Priority Environment.

Remediation of soil contaminated with the heavy metal (Cd2+)

International Nuclear Information System (INIS)

Lin, C.-C.; Lin, H.-L.

2005-01-01

Soil contamination by heavy metals is increasing. The biosorption process for removal of the heavy metal Cd 2+ from contaminated soil is chosen for this study due to its economy, commercial applications, and because it acts without destroying soil structure. The study is divided into four parts (1) soil leaching: the relationships between the soil leaching effect and agitation rates, solvent concentrations, ratios of soil to solvent, leaching time and pH were studied to identify their optimum conditions; (2) adsorption Cd 2+ tests of immobilized Saccharomycetes pombe beads: different weight percentages of chitosan and polyvinyl alcohol (PVAL) were added to alginate (10 wt.%) and then blended or cross-linked by epichlorohydrin (ECH) to increase their mechanical strength. Next, before blending or cross-linking, different weight percentages of S. pombe 806 or S. pombe ATCC 2476 were added to increase Cd 2+ adsorption. Thus, the optimum beads (blending or cross-linking, the percentages of chitosan, PVAL and S. pombe 806 or S. pombe ATCC 2476) and the optimum adsorption conditions (agitation rate, equilibrium adsorption time, and pH in the aqueous solution) were ascertained; (3) regeneration tests of the optimum beads: the optimum beads adsorbing Cd 2+ were regenerated by various concentrations of aqueous HCl solutions. The results indicate that the reuse of immobilized pombe beads was feasible; and (4) adsorption model/kinetic model/thermodynamic property: the equilibrium adsorption, kinetics, change in Gibbs free energy of adsorption of Cd 2+ on optimum beads were also investigated

Linking activity, composition and seasonal dynamics of atmospheric methane oxidizers in a meadow soil.

Science.gov (United States)

Shrestha, Pravin Malla; Kammann, Claudia; Lenhart, Katharina; Dam, Bomba; Liesack, Werner

2012-06-01

Microbial oxidation is the only biological sink for atmospheric methane. We assessed seasonal changes in atmospheric methane oxidation and the underlying methanotrophic communities in grassland near Giessen (Germany), along a soil moisture gradient. Soil samples were taken from the surface layer (0-10 cm) of three sites in August 2007, November 2007, February 2008 and May 2008. The sites showed seasonal differences in hydrological parameters. Net uptake rates varied seasonally between 0 and 70 μg CH(4) m(-2) h(-1). Greatest uptake rates coincided with lowest soil moisture in spring and summer. Over all sites and seasons, the methanotrophic communities were dominated by uncultivated methanotrophs. These formed a monophyletic cluster defined by the RA14, MHP and JR1 clades, referred to as upland soil cluster alphaproteobacteria (USCα)-like group. The copy numbers of pmoA genes ranged between 3.8 × 10(5)-1.9 × 10(6) copies g(-1) of soil. Temperature was positively correlated with CH(4) uptake rates (P50 vol% and primarily related to members of the MHP clade.

Riparian soil development linked to forest succession above and below dams along the Elwha River, Washington, USA

Science.gov (United States)

Perry, Laura G; Shafroth, Patrick B.; Perakis, Steven

2017-01-01

Riparian forest soils can be highly dynamic, due to frequent fluvial disturbance, erosion, and sediment deposition, but effects of dams on riparian soils are poorly understood. We examined soils along toposequences within three river segments located upstream, between, and downstream of two dams on the Elwha River to evaluate relationships between riparian soil development and forest age, succession, and channel proximity, explore dam effects on riparian soils, and provide a baseline for the largest dam removal in history. We found that older, later-successional forests and geomorphic surfaces contained soils with finer texture and greater depth to cobble, supporting greater forest floor mass, mineral soil nutrient levels, and cation exchange. Forest stand age was a better predictor than channel proximity for many soil characteristics, though elevation and distance from the channel were often also important, highlighting how complex interactions between fluvial disturbance, sediment deposition, and biotic retention regulate soil development in this ecosystem. Soils between the dams, and to a lesser extent below the lower dam, had finer textures and higher mineral soil carbon, nitrogen, and cation exchange than above the dams. These results suggested that decreased fluvial disturbance below the dams, due to reduced sediment supply and channel stabilization, accelerated soil development. In addition, reduced sediment supply below the dams may have decreased soil phosphorus. Soil δ15N suggested that salmon exclusion by the dams had no discernable effect on nitrogen inputs to upstream soils. Recent dam removal may alter riparian soils further, with ongoing implications for riparian ecosystems.

SPIDERS (ARANEI IN HEPRETOBIONT MESOFAUNA OF THE NORTHWEST CAUCASUS

Directory of Open Access Journals (Sweden)

A. V. Ponomarev

2014-01-01

Full Text Available Abstract. Aim. We discussed in previous work a herpetobiont fauna of arachnids (Arachnida from the isolated yewboxwood wood, located in the Caucasian State Biosphere Reserve, 20 km near Sochi (Ponomarev, Chumachenko, 2007. The aim of the paper is to summarize available data about herpetobiont araneofauna of the Northwest Caucasus. Location. Republic of Adygea, Russia.Methods. Material was collected in 2009 on north macroslope of Main Caucasian Ridge within the territory of the Caucasian State Biosphere Reserve between 1000–1820 m. The following plant communities are studied: beech-silver fir (assotiation Abieti-Fagetion orientalis Korotkov et Belonovskaya 1987, maple forest (assotiation Petasito albae-Abietetum nordmannianae subassotiation Aceretosum trautvetteri Francuzov 2006, subalpine meadow (assotiation Poa longifolii – Calamagrostietum arundinaceae Semagina, 1992. Soil traps were used for collection of spiders.Results and main conclusions. During the period of study 100 species of spiders from 19 families are registered. Most diverse araneofauna of subalpine meadows includs 54 species belonging to 14 families. The least diverse araneofauna is in maple forest (24 species of 7 families. In beech-silver fir includes 45 species of 16 families of spiders. Only 3 species (Pireneitega ovtchinnikovi, Cybaeus abchasicus, Tenuiphantes mengei were found in all surveyed habitats. These 3 species clearly tend to forest habitats. Herpetobiont araneofauna of the Northwest Caucasus characterized by high taxonomic diversity with clear predominance of representatives of the family Linyphiidae. Specificity of araneofauna in different types of plant communities is high.

Soil Fumigant Labels - Methyl Bromide

Science.gov (United States)

Search soil fumigant pesticide labels by EPA registration number, product name, or company, and follow the link to The Pesticide Product Label System (PPLS) for details. Updated labels include new safety requirements for buffer zones and related measures.

Speciation of zinc in contaminated soils

International Nuclear Information System (INIS)

Stephan, Chadi H.; Courchesne, Francois; Hendershot, William H.; McGrath, Steve P.; Chaudri, Amar M.; Sappin-Didier, Valerie; Sauve, Sebastien

2008-01-01

The chemical speciation of zinc in soil solutions is critical to the understanding of its bioavailability and potential toxic effects. We studied the speciation of Zn in soil solution extracts from 66 contaminated soils representative of a wide range of field conditions in both North America and Europe. Within this dataset, we evaluated the links among the dissolved concentrations of zinc and the speciation of Zn 2+ , soil solution pH, total soil Zn, dissolved organic matter (DOM), soil organic matter (SOM) and the concentrations of different inorganic anions. The solid-liquid partitioning coefficient (K d ) for Zn ranged from 17 to 13,100 L kg -1 soil. The fraction of dissolved Zn bound to DOM varied from 60% to 98% and the soil solution free Zn 2+ varied from 40% to 60% of the labile Zn. Multiple regression equations to predict free Zn 2+ , dissolved Zn and the solid-liquid partitioning of Zn are given for potential use in environmental fate modeling and risk assessment. The multiple regressions also highlight some of the most important soil properties controlling the solubility and chemical speciation of zinc in contaminated soils. - We studied the relationships among the chemical speciation of Zn in soil solution extracts from 66 contaminated soils and various physicochemical properties of the soils

Variable pore connectivity model linking gas diffusivity and air-phase tortuosity to soil matric potential

DEFF Research Database (Denmark)

Chamindu, Deepagoda; Møldrup, Per; Schjønning, Per

2012-01-01

information on soil functional pore structure, e.g., pore network tortuosity and connectivity, can also be revealed from Dp/Do–ψ relations. Based on Dp/Do measurements in a wide range of soil types across geographically remote vadose zone profiles, this study analyzed pore connectivity for the development...... of a variable pore connectivity factor, X, as a function of soil matric potential, expressed as pF (=log |−ψ|), for pF values ranging from 1.0 to 3.5. The new model takes the form of X = X* (F/F*)A with F = 1 + pF−1, where X* is the pore network tortuosity at reference F (F*) and A is a model parameter......- and intraaggregate pore regions of aggregated soils. We further suggest that the new model with parameter values of X* = 1.7 and A = 0 may be used for upper limit Dp/Do predictions in risk assessments of, e.g., fluxes of toxic volatile organics from soil to indoor air at polluted soil sites....

Comparing measured and modelled soil carbon: which site-specific variables are linked to high stability?

Science.gov (United States)

Robertson, Andy; Schipanski, Meagan; Ma, Liwang; Ahuja, Lajpat; McNamara, Niall; Smith, Pete; Davies, Christian

2016-04-01

Changes in soil carbon (C) stocks have been studied in depth over the last two decades, as net greenhouse gas (GHG) sinks are highlighted to be a partial solution to the causes of climate change. However, the stability of this soil C is often overlooked when measuring these changes. Ultimately a net sequestration in soils is far less beneficial if labile C is replacing more stable forms. To date there is no accepted framework for measuring soil C stability, and as a result there is considerable uncertainty associated with the simulated impacts of land management and land use change when using process-based systems models. However, a recent effort to equate measurable soil C fractions to model pools has generated data that help to assess the impacts of land management, and can ultimately help to reduce the uncertainty of model predictions. Our research compiles this existing fractionation data along with site metadata to create a simplistic statistical model able to quantify the relative importance of different site-specific conditions. Data was mined from 23 published studies and combined with original data to generate a dataset of 100+ land use change sites across Europe. For sites to be included they required soil C fractions isolated using the Zimmermann et al. (2007) method and specific site metadata (mean annual precipitation, MAP; mean annual temperature, MAT; soil pH; land use; altitude). Of the sites, 75% were used to develop a generalized linear mixed model (GLMM) to create coefficients where site parameters can be used to predict influence on the measured soil fraction C stocks. The remaining 25% of sites were used to evaluate uncertainty and validate this empirical model. Further, four of the aforementioned sites were used to simulate soil C dynamics using the RothC, DayCent and RZWQM2 models. A sensitivity analysis (4096 model runs for each variable applying Latin hypercube random sampling techniques) was then used to observe whether these models place

Expanding the horizons of soil science to the public

Science.gov (United States)

Lindbo, David L.; Hopmans, Jan; Olson, Carolyn; Fisk, Susan; Chapman, Susan

2015-04-01

Soils are critical to all life on the planet yet most individuals treat soil like dirt. As soil scientist we have long recognized this and have struggled to find ways to communicate the importance of soils to the public. The goal is not purely altruistic as we recognize that society funds or research and provides the workforce in soils that we need to continue to gain knowledge and expertise in soil science. In 2006 the Soil Science Society of America took a bold move and created its K12 Committee in part to compliment the Dig It! The Secrets of Soil exhibit that opened in July 2008 at the Smithsonian's Institution's Nation Museum of Natural History (of which SSS was a founding sponsor). The committee's work began quickly with a website designed to provide resources for K12 teachers (primary and school teachers). The first accomplishments included reviewing and posting links to web based information already available to teachers. These links were sorted by subject and grade level to make it easier for teachers to navigate the web and find what they needed quickly. Several presentations and lessons designed for K12 teachers were also posted at this time. Concurrent with this effort a subcommittee review and organized the national teaching standards to show where soils could fit into the overall K12 curriculum. As the website was being developed another subcommittee developed a soils book (Soil! Get the Inside Scoop, 2008) to further compliment the Dig It! exhibit. This was a new endeavor for SSSA having never worked with the non-academic audience in developing a book. Peer-reviews of this book included not only scientist but also students in order to make sure the book was attractive to them. Once the book was published and the website developed it became clear more outreach was needed. SSSA K12 Committee has attended both the National Science Teachers Association (since 2008) the USA Science and Engineering Festival (since 2010) with exhibits and workshops. It has

Soils and public health: the vital nexus

Science.gov (United States)

Pachepsky, Yakov

2015-04-01

Soils sustain life. They affect human health via quantity, quality, and safety of available food and water, and via direct exposure of individuals to soils. Throughout the history of civilization, soil-health relationships have inspired spiritual movements, philosophical systems, cultural exchanges, and interdisciplinary interactions, and provided medicinal substances of paramount impact. Given the climate, resource, and population pressures, understanding and managing the soil-health interactions becomes a modern imperative. We are witnessing a paradigm shift from recognizing and yet disregarding the 'soil-health' nexus complexity to parameterizing this complexity and identifying reliable controls. This becomes possible with the advent of modern research tools as a source of 'big data' on multivariate nonlinear soil systems and the multiplicity of health metrics. The phenomenon of suppression of human pathogens in soils and plants presents a recent example of these developments. Evidence is growing about the dependence of pathogen suppression on the soil microbial community structure which, in turn, is affected by the soil-plant system management. Soil eutrophication appears to create favorable conditions for pathogen survival. Another example of promising information-rich research considers links and feedbacks between the soil microbial community structure and structure of soil physical pore space. The two structures are intertwined and involved in the intricate self-organization that controls soil services to public health. This, in particular, affects functioning of soils as a powerful water filter and the capacity of this filter with respect to emerging contaminants in both 'green' and 'blue' waters. To evaluate effects of soil services to public health, upscaling procedures are needed for relating the fine-scale mechanistic knowledge to available coarse-scale information on soil properties and management. More needs to be learned about health effects of soils

Soil Penetration by Earthworms and Plant Roots--Mechanical Energetics of Bioturbation of Compacted Soils.

Directory of Open Access Journals (Sweden)

Siul Ruiz

Full Text Available We quantify mechanical processes common to soil penetration by earthworms and growing plant roots, including the energetic requirements for soil plastic displacement. The basic mechanical model considers cavity expansion into a plastic wet soil involving wedging by root tips or earthworms via cone-like penetration followed by cavity expansion due to pressurized earthworm hydroskeleton or root radial growth. The mechanical stresses and resulting soil strains determine the mechanical energy required for bioturbation under different soil hydro-mechanical conditions for a realistic range of root/earthworm geometries. Modeling results suggest that higher soil water content and reduced clay content reduce the strain energy required for soil penetration. The critical earthworm or root pressure increases with increased diameter of root or earthworm, however, results are insensitive to the cone apex (shape of the tip. The invested mechanical energy per unit length increase with increasing earthworm and plant root diameters, whereas mechanical energy per unit of displaced soil volume decreases with larger diameters. The study provides a quantitative framework for estimating energy requirements for soil penetration work done by earthworms and plant roots, and delineates intrinsic and external mechanical limits for bioturbation processes. Estimated energy requirements for earthworm biopore networks are linked to consumption of soil organic matter and suggest that earthworm populations are likely to consume a significant fraction of ecosystem net primary production to sustain their subterranean activities.

Modeling stomatal conductance in the earth system: linking leaf water-use efficiency and water transport along the soil-plant-atmosphere continuum

Science.gov (United States)

Bonan, G. B.; Williams, M.; Fisher, R. A.; Oleson, K. W.

2014-09-01

The Ball-Berry stomatal conductance model is commonly used in earth system models to simulate biotic regulation of evapotranspiration. However, the dependence of stomatal conductance (gs) on vapor pressure deficit (Ds) and soil moisture must be empirically parameterized. We evaluated the Ball-Berry model used in the Community Land Model version 4.5 (CLM4.5) and an alternative stomatal conductance model that links leaf gas exchange, plant hydraulic constraints, and the soil-plant-atmosphere continuum (SPA). The SPA model simulates stomatal conductance numerically by (1) optimizing photosynthetic carbon gain per unit water loss while (2) constraining stomatal opening to prevent leaf water potential from dropping below a critical minimum. We evaluated two optimization algorithms: intrinsic water-use efficiency (ΔAn /Δgs, the marginal carbon gain of stomatal opening) and water-use efficiency (ΔAn /ΔEl, the marginal carbon gain of transpiration water loss). We implemented the stomatal models in a multi-layer plant canopy model to resolve profiles of gas exchange, leaf water potential, and plant hydraulics within the canopy, and evaluated the simulations using leaf analyses, eddy covariance fluxes at six forest sites, and parameter sensitivity analyses. The primary differences among stomatal models relate to soil moisture stress and vapor pressure deficit responses. Without soil moisture stress, the performance of the SPA stomatal model was comparable to or slightly better than the CLM Ball-Berry model in flux tower simulations, but was significantly better than the CLM Ball-Berry model when there was soil moisture stress. Functional dependence of gs on soil moisture emerged from water flow along the soil-to-leaf pathway rather than being imposed a priori, as in the CLM Ball-Berry model. Similar functional dependence of gs on Ds emerged from the ΔAn/ΔEl optimization, but not the ΔAn /gs optimization. Two parameters (stomatal efficiency and root hydraulic

Linking activity, composition and seasonal dynamics of atmospheric methane oxidizers in a meadow soil

Science.gov (United States)

Shrestha, Pravin Malla; Kammann, Claudia; Lenhart, Katharina; Dam, Bomba; Liesack, Werner

2012-01-01

Microbial oxidation is the only biological sink for atmospheric methane. We assessed seasonal changes in atmospheric methane oxidation and the underlying methanotrophic communities in grassland near Giessen (Germany), along a soil moisture gradient. Soil samples were taken from the surface layer (0–10 cm) of three sites in August 2007, November 2007, February 2008 and May 2008. The sites showed seasonal differences in hydrological parameters. Net uptake rates varied seasonally between 0 and 70 μg CH4 m−2 h−1. Greatest uptake rates coincided with lowest soil moisture in spring and summer. Over all sites and seasons, the methanotrophic communities were dominated by uncultivated methanotrophs. These formed a monophyletic cluster defined by the RA14, MHP and JR1 clades, referred to as upland soil cluster alphaproteobacteria (USCα)-like group. The copy numbers of pmoA genes ranged between 3.8 × 105–1.9 × 106 copies g−1 of soil. Temperature was positively correlated with CH4 uptake rates (P50 vol% and primarily related to members of the MHP clade. PMID:22189499

Assessing the dynamics of the upper soil layer relative to soil management practices

Science.gov (United States)

Hatfield, J.; Wacha, K.; Dold, C.

2017-12-01

The upper layer of the soil is the critical interface between the soil and the atmosphere and is the most dynamic in response to management practices. One of the soil properties most reflective to changes in management is the stability of the aggregates because this property controls infiltration of water and exchange of gases. An aggregation model has been developed based on the factors that control how aggregates form and the forces which degrade aggregates. One of the major factors for this model is the storage of carbon into the soil and the interaction with the soil biological component. To increase soil biology requires a stable microclimate that provides food, water, shelter, and oxygen which in turn facilitates the incorporation of organic material into forms that can be combined with soil particles to create stable aggregates. The processes that increase aggregate size and stability are directly linked the continual functioning of the biological component which in turn changes the physical and chemical properties of the soil. Soil aggregates begin to degrade as soon as there is no longer a supply of organic material into the soil. These processes can range from removal of organic material and excessive tillage. To increase aggregation of the upper soil layer requires a continual supply of organic material and the biological activity that incorporates organic material into substances that create a stable aggregate. Soils that exhibit stable soil aggregates at the surface have a prolonged infiltration rate with less runoff and a gas exchange that ensures adequate oxygen for maximum biological activity. Quantifying the dynamics of the soil surface layer provides a quantitative understanding of how management practices affect aggregate stability.

Climate Strategic Soil Management

Directory of Open Access Journals (Sweden)

Rattan Lal

2014-02-01

Full Text Available The complex and strong link between soil degradation, climate change and food insecurity is a global challenge. Sustainable agricultural systems must be integral to any agenda to address climate change and variability, improve renewable fresh water supply and quality, restore degraded soils and ecosystems and advance food security. These challenges are being exacerbated by increasing population and decreasing per capita arable land area and renewable fresh water supply, the increasing frequency of extreme events, the decreasing resilience of agroecosystems, an increasing income and affluent lifestyle with growing preference towards meat-based diet and a decreasing soil quality and use efficiency of inputs. Reversing these downward spirals implies the implementation of proven technologies, such as conservation agriculture, integrated nutrient management, precision agriculture, agroforestry systems, etc. Restoration of degraded soil and desertified ecosystems and the creation of positive soil and ecosystem C budgets are important. Urban agriculture and green roofs can reduce the energy footprint of production chains for urban and non-urban areas and enhance the recycling of by-products. Researchable priorities include sustainable land use and soil/water management options, judicious soil governance and modus operandi towards payments to land managers for the provisioning of ecosystem services.

From Process Understanding Via Soil Functions to Sustainable Soil Management - A Systemic Approach

Science.gov (United States)

Wollschlaeger, U.; Bartke, S.; Bartkowski, B.; Daedlow, K.; Helming, K.; Kogel-Knabner, I.; Lang, B.; Rabot, E.; Russell, D.; Stößel, B.; Weller, U.; Wiesmeier, M.; Rabot, E.; Vogel, H. J.

2017-12-01

Fertile soils are central resources for the production of biomass and the provision of food and energy. A growing world population and latest climate targets lead to an increasing demand for both, food and bio-energy, which requires preserving and improving the long-term productivity of soils as a bio-economic resource. At the same time, other soil functions and ecosystem services need to be maintained: filter for clean water, carbon sequestration, provision and recycling of nutrients, and habitat for biological activity. All these soil functions result from the interaction of a multitude of physical, chemical and biological processes that are not yet sufficiently understood. In addition, we lack understanding about the interplay between the socio-economic system and the soil system and how soil functions benefit human wellbeing. Hence, a solid and integrated assessment of soil quality requires the consideration of the ensemble of soil functions and its relation to soil management to finally be able to develop site-specific options for sustainable soil management. We present an integrated modeling approach that investigates the influence of soil management on the ensemble of soil functions. It is based on the mechanistic relationships between soil functional attributes, each explained by a network of interacting processes as derived from scientific evidence. As the evidence base required for feeding the model is for the most part stored in the existing scientific literature, another central component of our work is to set up a public "knowledge-portal" providing the infrastructure for a community effort towards a comprehensive knowledge base on soil processes as a basis for model developments. The connection to the socio-economic system is established using the Drivers-Pressures-Impacts-States-Responses (DPSIR) framework where our improved understanding about soil ecosystem processes is linked to ecosystem services and resource efficiency via the soil functions.

Polycyclic aromatic hydrocarbons bioavailability in industrial and agricultural soils: Linking SPME and Tenax extraction with bioassays.

Science.gov (United States)

Guo, Meixia; Gong, Zongqiang; Li, Xiaojun; Allinson, Graeme; Rookes, James; Cahill, David

2017-06-01

The aims of this study were to evaluate the bioavailability of polycyclic aromatic hydrocarbons (PAHs) in industrial and agricultural soils using chemical methods and a bioassay, and to study the relationships between the methods. This was conducted by comparing the quantities of PAHs extracted from two manufactured gas plant (MGP) soils and an agricultural soil with low level contamination by solid-phase micro-extraction (SPME) and Tenax-TA extraction with the quantities taken up by the earthworm (Eisenia fetida). In addition, a biodegradation experiment was conducted on one MGP soil (MGP-A) to clarify the relationship between PAH removal by biodegradation and the variation in PAH concentrations in soil pore water. Results demonstrated that the earthworm bioassay could not be used to examine PAH bioavailability in the tested MGP soils; which was the case even in the diluted MGP-A soils after biodegradation. However, the bioassay was successfully applied to the agricultural soil. These results suggest that earthworms can only be used for bioassays in soils with low toxicity. In general, rapidly desorbing concentrations extracted by Tenax-TA could predict PAH concentrations accumulated in earthworms (R 2 =0.66), while SPME underestimated earthworm concentrations by a factor of 2.5. Both SPME and Tenax extraction can provide a useful tool to predict PAH bioavailability for earthworms, but Tenax-TA extraction was proven to be a more sensitive and precise method than SPME for the prediction of earthworm exposure in the agricultural soil. Copyright © 2017. Published by Elsevier Inc.

Integrating soil physical and biological properties in contrasting tillage systems in organic and conventional farming

NARCIS (Netherlands)

Crittenden, S.J.; Goede, de R.G.M.

2016-01-01

Though soil physical and soil biological properties are intrinsically linked in the soil environment they are often studied separately. This work adds value to analyses of soil biophysical quality of tillage systems under organic and conventional farming systems by correlating physical and

Linking stoichiometric homeostasis of microorganisms with soil phosphorus dynamics in wetlands subjected to microcosm warming.

Directory of Open Access Journals (Sweden)

Hang Wang

Full Text Available Soil biogeochemical processes and the ecological stability of wetland ecosystems under global warming scenarios have gained increasing attention worldwide. Changes in the capacity of microorganisms to maintain stoichiometric homeostasis, or relatively stable internal concentrations of elements, may serve as an indicator of alterations to soil biogeochemical processes and their associated ecological feedbacks. In this study, an outdoor computerized microcosm was set up to simulate a warmed (+5°C climate scenario, using novel, minute-scale temperature manipulation technology. The principle of stoichiometric homeostasis was adopted to illustrate phosphorus (P biogeochemical cycling coupled with carbon (C dynamics within the soil-microorganism complex. We hypothesized that enhancing the flux of P from soil to water under warming scenarios is tightly coupled with a decrease in homeostatic regulation ability in wetland ecosystems. Results indicate that experimental warming impaired the ability of stoichiometric homeostasis (H to regulate biogeochemical processes, enhancing the ecological role of wetland soil as an ecological source for both P and C. The potential P flux from soil to water ranged from 0.11 to 34.51 mg m(-2 d(-1 in the control and 0.07 to 61.26 mg m(-2 d(-1 in the warmed treatment. The synergistic function of C-P acquisition is an important mechanism underlying C∶P stoichiometric balance for soil microorganisms under warming. For both treatment groups, strongly significant (p<0.001 relationships fitting a negative allometric power model with a fractional exponent were found between n-HC∶P (the specialized homeostatic regulation ability as a ratio of soil highly labile organic carbon to dissolved reactive phosphorus in porewater and potential P flux. Although many factors may affect soil P dynamics, the n-HC∶P term fundamentally reflects the stoichiometric balance or interactions between the energy landscape (i.e., C and flow of

Evaluation of scour potential of cohesive soils : final report, August 2009.

Science.gov (United States)

2009-08-01

Prediction of scour at bridge river crossings is an evolving process. Hydraulic models to estimate water velocity and, therefore, the shear stresses that erode soil are reasonably well developed. The weak link remains methods for estimating soil erod...

Finnish Society of Soil Sciences

Science.gov (United States)

Rankinen, Katri; Hänninen, Pekka; Soinne, Helena; Leppälammi-Kujansuu, Jaana; Salo, Tapio; Pennanen, Taina

2017-04-01

In 1998 the organization of the International Union of Soil Sciences (IUSS) was renewed to better support national activities. That was also the new start in the operation of the Finnish Society of Soil Sciences, which became affiliated to the IUSS. The society was originally established in 1971 but it remained relatively inactive. Currently, there are around 200 members in the Finnish Society of Soil Sciences. The members of the executive board cover different fields of soil science from geology to microbiology. Mission statement of the society is to promote the soil sciences and their application in Finland, to act as a forum for creation of better links between soil scientists, interested end users and the public, and to promote distribution and appreciation of general and Finnish research findings in soil science. Every second year the society organizes a national two-day long conference. In 2017 the theme 'circular economy' collected all together 57 presentations. The members of the incoming student division carried responsibility in practical co-ordination committee, acting also as session chairs. In the intervening years the society organizes a weekend excursion to neighboring areas. Lately we have explored the use of biochar in landscaping of Stockholm.

Soil enzymology in the recycling of organic wastes and environmental restoration

Energy Technology Data Exchange (ETDEWEB)

Trasar-Cepeda, Carmen [IIAG-CSIC, Santiago de Compostela (Spain). Dept. de Bioquimica del Suelo; Rad, Carlos [Burgos Univ. (Spain). Soil Science and Agricultural Chemistry, Faculty of Science; Hernandez, Teresa; Garcia, Carlos (eds.) [CEBAS-CSIC, Murcia (Spain). Dept. of Soil and Water Conservation; Gonzalez-Carcedo, Salvador [Burgos Univ. (Spain). Soil Science and Agricultural Chemistry, Polytechnic High School

2012-07-01

Soil enzymes play a fundamental role in many soil processes such as the mineralization of organic matter, the synthesis of humic substances, the degradation of xenobiotics or the mechanisms involved in the biocontrol of plant pathogens. Their direct link with soil microorganisms gives them a key role as biomonitors of the evolution of soil quality or in the monitoring of the application of organic amendments to degraded soils. As a consequence of the importance of soil enzymes on soil processes, there is an increasing interest in their study, as well as in the application of molecular techniques as diagnostic tools. (orig.)

Leaching of soils during laboratory incubations does not affect soil organic carbon mineralisation but solubilisation.

Science.gov (United States)

González-Domínguez, Beatriz; Studer, Mirjam S; Hagedorn, Frank; Niklaus, Pascal A; Abiven, Samuel

2017-01-01

Laboratory soil incubations provide controlled conditions to investigate carbon and nutrient dynamics; however, they are not free of artefacts. As carbon and nitrogen cycles are tightly linked, we aimed at investigating whether the incubation-induced accumulation of mineral nitrogen (Nmin) biases soil organic carbon (SOC) mineralisation. For this, we selected two soils representative of the C:N ratio values found in European temperate forests, and applied two incubation systems: 'closed' beakers and 'open' microlysimeters. The latter allowed leaching the soil samples during the incubation. By the end of the 121-day experiment, the low C:N soil significantly accumulated more Nmin in beakers (5.12 g kg-1 OC) than in microlysimeters (3.00 g kg-1 OC) but there was not a significant difference in SOC mineralisation at any point of the experiment. On the other hand, Nmin did not accumulate in the high C:N soil but, by the end of the experiment, leaching had promoted 33.9% more SOC solubilisation than beakers. Therefore, we did not find evidence that incubation experiments introduce a bias on SOC mineralisation. This outcome strengthens results from soil incubation studies.

Biological Activity Assessment in Mexican Tropical Soils with Different Hydrocarbon Contamination Histories

OpenAIRE

Riveroll-Larios, Jessica; Escalante-Espinosa, Erika; Fócil-Monterrubio, Reyna L.; Díaz-Ramírez, Ildefonso J.

2015-01-01

The use of soil health indicators linked to microbial activities, such as key enzymes and respirometric profiles, helps assess the natural attenuation potential of soils contaminated with hydrocarbons. In this study, the intrinsic physicochemical characteristics, biological activity and biodegradation potential were recorded for two soils with different contamination histories (>5 years and

The status of soil mapping for the Idaho National Engineering Laboratory

International Nuclear Information System (INIS)

Olson, G.L.; Lee, R.D.; Jeppesen, D.J.

1995-01-01

This report discusses the production of a revised version of the general soil map of the 2304-km 2 (890-mi 2 ) Idaho National Engineering Laboratory (INEL) site in southeastern Idaho and the production of a geographic information system (GIS) soil map and supporting database. The revised general soil map replaces an INEL soil map produced in 1978 and incorporates the most current information on INEL soils. The general soil map delineates large soil associations based on National Resources Conservation Services [formerly the Soil Conservation Service (SCS)] principles of soil mapping. The GIS map incorporates detailed information that could not be presented on the general soil map and is linked to a database that contains the soil map unit descriptions, surficial geology codes, and other pertinent information

Bromine accumulation in acidic black colluvial soils

Science.gov (United States)

Martínez Cortizas, Antonio; Ferro Vázquez, Cruz; Kaal, Joeri; Biester, Harald; Costa Casais, Manuela; Taboada Rodríguez, Teresa; Rodríguez Lado, Luis

2016-02-01

Recent investigations showed that bromine is incorporated to soil organic matter (SOM), its content increasing with humification. But few research was done on its long-term accumulation and the role played by pedogenetic processes, as those involved in organic matter stabilization. We investigated bromine content and distribution in four deep, acidic, organic-rich, Holocene soils from an oceanic area of Western Europe. Bromine concentrations (93-778 μg g-1) in the silt + clay (stabilized as aluminium-OM associations, and to a lesser extent on soil acidity (pH) and iron-OM associations. Thus, at scales of thousands of years, bromine accumulation in acidic soils is linked to the pool of metal-clay-stabilized organic matter.

Plant biomass increase linked to biological activity in soils amended with sewage sludge compost

International Nuclear Information System (INIS)

Ibanez-Burgos, A.; Lopez-Lopez, G.; Vera, J.; Rovira, J. M.; Reolid, C.; Sastre-Conde, I.

2009-01-01

Sewage sludge compost application to almond tree plantations presents a potential management alternative to combat soil mismanagement in Mediterranean areas where almonds are grown. this practice could also be used to restore vegetable biomass to soils which are not fertile enough to support other crops, as well as to fight climatic change. (Author)

Plant biomass increase linked to biological activity in soils amended with sewage sludge compost

Energy Technology Data Exchange (ETDEWEB)

Ibanez-Burgos, A.; Lopez-Lopez, G.; Vera, J.; Rovira, J. M.; Reolid, C.; Sastre-Conde, I.

2009-07-01

Sewage sludge compost application to almond tree plantations presents a potential management alternative to combat soil mismanagement in Mediterranean areas where almonds are grown. this practice could also be used to restore vegetable biomass to soils which are not fertile enough to support other crops, as well as to fight climatic change. (Author)

Relationships between soil properties and community structure of soil macroinvertebrates in oak-history forests along an acidic deposition gradient

Energy Technology Data Exchange (ETDEWEB)

Kuperman, R.G. [Argonne National Lab., IL (United States). Environmental Assessment Div.

1996-02-01

Soil macroinvertebrate communities were studied in ecologically analogous oak-hickory forests across a three-state atmospheric pollution gradient in Illinois, Indiana, and Ohio. The goal was to investigate changes in the community structure of soil fauna in study sites receiving different amounts of acidic deposition for several decades and the possible relationships between these changes and physico-chemical properties of soil. The study revealed significant differences in the numbers of soil animals among the three study sites. The sharply differentiated pattern of soil macroinvertebrate fauna seems closely linked to soil chemistry. Significant correlations of the abundance of soil macroinvertebrates with soil parameters suggest that their populations could have been affected by acidic deposition in the region. Abundance of total soil macroinvertebrates decreased with the increased cumulative loading of acidic deposition. Among the groups most sensitive to deposition were: earthworms gastropods, dipteran larvae, termites, and predatory beetles. The results of the study support the hypothesis that chronic long-term acidic deposition could aversely affect the soil decomposer community which could cause lower organic matter turnover rates leading to an increase in soil organic matter content in high deposition sites.

Plant stimulation of soil microbial community succession: how sequential expression mediates soil carbon stabilization and turnover

Energy Technology Data Exchange (ETDEWEB)

Firestone, Mary [Univ. of California, Berkeley, CA (United States)

2015-03-31

It is now understood that most plant C is utilized or transformed by soil microorganisms en route to stabilization. Hence the composition of microbial communities that mediate decomposition and transformation of root C is critical, as are the metabolic capabilities of these communities. The change in composition and function of the C-transforming microbial communities over time in effect defines the biological component of soil C stabilization. Our research was designed to test 2 general hypotheses; the first two hypotheses are discussed first; H1: Root-exudate interactions with soil microbial populations results in the expression of enzymatic capacities for macromolecular, complex carbon decomposition; and H2: Microbial communities surrounding roots undergo taxonomic succession linked to functional gene activities as roots grow, mature, and decompose in soil. Over the term of the project we made significant progress in 1) quantifying the temporal pattern of root interactions with the soil decomposing community and 2) characterizing the role of root exudates in mediating these interactions.

Exoemission of Ethiopian soils and the endemicity of non-filarial elephantiasis

Energy Technology Data Exchange (ETDEWEB)

Davies, J.E. (Birmingham Univ. (UK). Dept. of Anatomy); Townsend, P.D. (Sussex Univ., Brighton (UK))

1983-01-01

Non-filarial elephantiasis is an endemic disease in the bare-footed population of Ethiopia. The distribution of this condition is linked with that of local red clay soil. Recently, thermoluminescence has been successfully used to distinguish between endemic and non-endemic soils. Instrinsic lattice defects, frozen in during cooling of volcanic material, are considered to be responsible for characteristic thermoluminescence signals. However, the biological reactivity of the absorbed soil particles will depend upon their surface properties. Exoemission has therefore been studied in samples from both endemic (5 samples) and non-endemic (4 samples) areas. All samples from endemic areas, on first heating, demonstrate an emission peak at 75/sup 0/C. Post-irradiation storage of samples in a moist atmosphere tends to decrease emissivity while wetting irreversibly reduces the response to irradiation. In an hydrated biological environment, this surface reactivity may be linked to the pathogenicity of the soil particles.

Exoemission of Ethiopian soils and the endemicity of non-filarial elephantiasis

International Nuclear Information System (INIS)

Davies, J.E.

1983-01-01

Non-filarial elephantiasis is an endemic disease in the bare-footed population of Ethiopia. The distribution of this condition is linked with that of local red clay soil. Recently, thermoluminescence has been successfully used to distinguish between endemic and non-endemic soils. Instrinsic lattice defects, frozen in during cooling of volcanic material, are considered to be responsible for characteristic thermoluminescence signals. However, the biological reactivity of the absorbed soil particles will depend upon their surface properties. Exoemission has therefore been studied in samples from both endemic (5 samples) and non-endemic (4 samples) areas. All samples from endemic areas, on first heating, demonstrate an emission peak at 75 0 C. Post-irradiation storage of samples in a moist atmosphere tends to decrease emissivity while wetting irreversibly reduces the response to irradiation. In an hydrated biological environement, this surface reactivity may be linked to the pathogenicity of the soil particles. (author)

Fire modifies the phylogenetic structure of soil bacterial co-occurrence networks.

Science.gov (United States)

Pérez-Valera, Eduardo; Goberna, Marta; Faust, Karoline; Raes, Jeroen; García, Carlos; Verdú, Miguel

2017-01-01

Fire alters ecosystems by changing the composition and community structure of soil microbes. The phylogenetic structure of a community provides clues about its main assembling mechanisms. While environmental filtering tends to reduce the community phylogenetic diversity by selecting for functionally (and hence phylogenetically) similar species, processes like competitive exclusion by limiting similarity tend to increase it by preventing the coexistence of functionally (and phylogenetically) similar species. We used co-occurrence networks to detect co-presence (bacteria that co-occur) or exclusion (bacteria that do not co-occur) links indicative of the ecological interactions structuring the community. We propose that inspecting the phylogenetic structure of co-presence or exclusion links allows to detect the main processes simultaneously assembling the community. We monitored a soil bacterial community after an experimental fire and found that fire altered its composition, richness and phylogenetic diversity. Both co-presence and exclusion links were more phylogenetically related than expected by chance. We interpret such a phylogenetic clustering in co-presence links as a result of environmental filtering, while that in exclusion links reflects competitive exclusion by limiting similarity. This suggests that environmental filtering and limiting similarity operate simultaneously to assemble soil bacterial communities, widening the traditional view that only environmental filtering structures bacterial communities. © 2016 Society for Applied Microbiology and John Wiley & Sons Ltd.

A review of the impacts of degradation threats on soil properties in the UK.

Science.gov (United States)

Gregory, A S; Ritz, K; McGrath, S P; Quinton, J N; Goulding, K W T; Jones, R J A; Harris, J A; Bol, R; Wallace, P; Pilgrim, E S; Whitmore, A P

2015-10-01

National governments are becoming increasingly aware of the importance of their soil resources and are shaping strategies accordingly. Implicit in any such strategy is that degradation threats and their potential effect on important soil properties and functions are defined and understood. In this paper, we aimed to review the principal degradation threats on important soil properties in the UK, seeking quantitative data where possible. Soil erosion results in the removal of important topsoil and, with it, nutrients, C and porosity. A decline in soil organic matter principally affects soil biological and microbiological properties, but also impacts on soil physical properties because of the link with soil structure. Soil contamination affects soil chemical properties, affecting nutrient availability and degrading microbial properties, whilst soil compaction degrades the soil pore network. Soil sealing removes the link between the soil and most of the 'spheres', significantly affecting hydrological and microbial functions, and soils on re-developed brownfield sites are typically degraded in most soil properties. Having synthesized the literature on the impact on soil properties, we discuss potential subsequent impacts on the important soil functions, including food and fibre production, storage of water and C, support for biodiversity, and protection of cultural and archaeological heritage. Looking forward, we suggest a twin approach of field-based monitoring supported by controlled laboratory experimentation to improve our mechanistic understanding of soils. This would enable us to better predict future impacts of degradation processes, including climate change, on soil properties and functions so that we may manage soil resources sustainably.

Linking current river pollution to historical pesticide use: Insights for territorial management?

Science.gov (United States)

Della Rossa, Pauline; Jannoyer, Magalie; Mottes, Charles; Plet, Joanne; Bazizi, Abderazak; Arnaud, Luc; Jestin, Alexandra; Woignier, Thierry; Gaude, Jean-Marie; Cattan, Philippe

2017-01-01

Persistent organic pollutants like organochlorine pesticides continue to contaminate large areas worldwide raising questions concerning their management. We designed and tested a method to link soil and water pollution in the watershed of the Galion River in Martinique. We first estimated the risk of soil contamination by chlordecone by referring to past use of land for banana cultivation and took 27 soil samples. We then sampled surface waters at 39 points and groundwater at 16 points. We tested three hypotheses linked to the source of chlordecone pollution at the watershed scale: (i) soils close to the river, (ii) soils close to the sampling point, (iii) throughout the sub-watershed generated at the sampling point. Graphical and statistical analysis showed that contamination of the river increased when it passed through an area with contaminated plots and decreased when it passed through area not contaminated by chlordecone. Modeling showed that the entire surface area of the watershed contributed to river pollution, suggesting that the river was mainly being contaminated by the aquifers and groundwater flows. Our method proved to be a reliable way to identify areas polluted by chlordecone at the watershed scale and should help stakeholders focus their management actions on both hot spots and the whole watershed. Copyright © 2016 Elsevier B.V. All rights reserved.

Mechanical impedance of soil crusts and water content in loamy soils

Science.gov (United States)

Josa March, Ramon; Verdú, Antoni M. C.; Mas, Maria Teresa

2013-04-01

Soil crust development affects soil water dynamics and soil aeration. Soil crusts act as mechanical barriers to fluid flow and, as their mechanical impedance increases with drying, they also become obstacles to seedling emergence. As a consequence, the emergence of seedling cohorts (sensitive seeds) might be reduced. However, this may be of interest to be used as an effective system of weed control. Soil crusting is determined by several factors: soil texture, rain intensity, sedimentation processes, etc. There are different ways to characterize the crusts. One of them is to measure their mechanical impedance (MI), which is linked to their moisture level. In this study, we measured the evolution of the mechanical impedance of crusts formed by three loamy soil types (clay loam, loam and sandy clay loam, USDA) with different soil water contents. The aim of this communication was to establish a mathematical relationship between the crust water content and its MI. A saturated soil paste was prepared and placed in PVC cylinders (50 mm diameter and 10 mm height) arranged on a plastic tray. Previously the plastic tray was sprayed with a hydrophobic liquid to prevent the adherence of samples. The samples on the plastic tray were left to air-dry under laboratory conditions until their IM was measured. To measure IM, a food texture analyzer was used. The equipment incorporates a mobile arm, a load cell to apply force and a probe. The arm moves down vertically at a constant rate and the cylindrical steel probe (4 mm diameter) penetrates the soil sample vertically at a constant rate. The equipment is provided with software to store data (time, vertical distance and force values) at a rate of up to 500 points per second. Water content in crust soil samples was determined as the loss of weight after oven-drying (105°C). From the results, an exponential regression between MI and the water content was obtained (determination coefficient very close to 1). This methodology allows

Links between soil properties and steady-state solute transport through cultivated topsoil at the field scale

DEFF Research Database (Denmark)

Koestel, J. K.; Nørgaard, Trine; Loung, N. M.

2013-01-01

It is known that solute transport through soil is heterogeneous at all spatial scales. However, little data are available to allow quantification of these heterogeneities at the field scale or larger. In this study, we investigated the spatial patterns of soil properties, hydrologic state variables......, and tracer breakthrough curves (BTCs) at the field scale for the inert solute transport under a steady-state irrigation rate which produced near-saturated conditions. Sixty-five undisturbed soil columns approximately 20 cm in height and diameter were sampled from the loamy topsoil of an agricultural field...... to larger water saturation and the activation of larger macropores. Our study provides further evidence that it should be possible to estimate solute transport properties from soil properties such as soil texture or bulk density. We also demonstrated that estimation approaches established for the column...

Biological soil crusts in deserts: A short review of their role in soil fertility, stabilization, and water relations

Science.gov (United States)

Belnap, Jayne

2003-01-01

Cyanobacteria and cyanolichens dominate most desert soil surfaces as the major component of biological soil crusts (BSC). BSCs contribute to soil fertility in many ways. BSC can increase weathering of parent materials by up to 100 times. Soil surface biota are often sticky, and help retain dust falling on the soil surface; this dust provides many plant-essential nutrients including N, P, K, Mg, Na, Mn, Cu, and Fe. BSCs also provide roughened soil surfaces that slow water runoff and aid in retaining seeds and organic matter. They provide inputs of newly-fixed carbon and nitrogen to soils. They are essential in stabilizing soil surfaces by linking soil particles together with filamentous sheaths, enabling soils to resist both water and wind erosion. These same sheaths are important in keeping soil nutrients from becoming bound into plant-unavailable forms. Experimental disturbances applied in US deserts show soil surface impacts decrease N and C inputs from soil biota by up to 100%. The ability to hold aeolian deposits in place is compromised, and underlying soils are exposed to erosion. While most undisturbed sites show little sediment production, disturbance by vehicles or livestock produces up to 36 times more sediment production, with soil movement initiated at wind velocities well below commonly-occurring wind speeds. Winds across disturbed areas can quickly remove this material from the soil surface, thereby potentially removing much of current and future soil fertility. Thus, reduction in the cover of cyanophytes in desert soils can both reduce fertility inputs and accelerate fertility losses.

Accounting for non-stationary variance in geostatistical mapping of soil properties

NARCIS (Netherlands)

Wadoux, Alexandre M.J.C.; Brus, Dick J.; Heuvelink, Gerard B.M.

2018-01-01

Simple and ordinary kriging assume a constant mean and variance of the soil variable of interest. This assumption is often implausible because the mean and/or variance are linked to terrain attributes, parent material or other soil forming factors. In kriging with external drift (KED)

Potential Carbon Transport: Linking Soil Aggregate Stability and Sediment Enrichment for Updating the Soil Active Layer within Intensely Managed Landscapes

Science.gov (United States)

Wacha, K.; Papanicolaou, T.; Abban, B. K.; Wilson, C. G.

2014-12-01

Currently, many biogeochemical models lack the mechanistic capacity to accurately simulate soil organic carbon (SOC) dynamics, especially within intensely managed landscapes (IMLs) such as those found in the U.S. Midwest. These modeling limitations originate by not accounting for downslope connectivity of flowpathways initiated and governed by landscape processes and hydrologic forcing, which induce dynamic updates to the soil active layer (generally top 20-30cm of soil) with various sediment size fractions and aggregates being transported and deposited along the downslope. These hydro-geomorphic processes, often amplified in IMLs by tillage events and seasonal canopy, can greatly impact biogeochemical cycles (e.g., enhanced mineralization during aggregate breakdown) and in turn, have huge implications/uncertainty when determining SOC budgets. In this study, some of these limitations were addressed through a new concept, Potential Carbon Transport (PCT), a term which quantifies a maximum amount of material available for transport at various positions of the landscape, which was used to further refine a coupled modeling framework focused on SOC redistribution through downslope/lateral connectivity. Specifically, the size fractions slaked from large and small aggregates during raindrop-induced aggregate stability tests were used in conjunction with rainfall-simulated sediment enrichment ratio (ER) experiments to quantify the PCT under various management practices, soil types and landscape positions. Field samples used in determining aggregate stability and the ER experiments were collected/performed within the historic Clear Creek Watershed, home of the IML Critical Zone Observatory, located in Southeastern Iowa.

Plant-plant competition outcomes are modulated by plant effects on the soil bacterial community.

Science.gov (United States)

Hortal, S; Lozano, Y M; Bastida, F; Armas, C; Moreno, J L; Garcia, C; Pugnaire, F I

2017-12-19

Competition is a key process that determines plant community structure and dynamics, often mediated by nutrients and water availability. However, the role of soil microorganisms on plant competition, and the links between above- and belowground processes, are not well understood. Here we show that the effects of interspecific plant competition on plant performance are mediated by feedbacks between plants and soil bacterial communities. Each plant species selects a singular community of soil microorganisms in its rhizosphere with a specific species composition, abundance and activity. When two plant species interact, the resulting soil bacterial community matches that of the most competitive plant species, suggesting strong competitive interactions between soil bacterial communities as well. We propose a novel mechanism by which changes in belowground bacterial communities promoted by the most competitive plant species influence plant performance and competition outcome. These findings emphasise the strong links between plant and soil communities, paving the way to a better understanding of plant community dynamics and the effects of soil bacterial communities on ecosystem functioning and services.

Dangerous enemy in Estonian garden soil

International Nuclear Information System (INIS)

Petersell, V.; Mottus, V.; Taeht, K.

2005-01-01

Radon is thoroughly discussed in the article. Its generation and the heath risks it can cause. The distribution of radon in the soil is analysed (one soil lithotype at a time (kBq/m)). The measurements received on different surveyed sites are compared to the standards allowed for the construction works. There is also the link between lung cancer cases and radon's radiance and incense/smoking. The North of Estonia is the pearl of Estonia landscape. The sea being near, beautiful seaside views attract people and inspire them to build their houses in this kind of surroundings. However, these areas are natural danger sources, as the percentage of radon concentration in the soil is often high or very high. South Estonia also has a lot of spectacular places with high concentration of radon in the soil [et

Linking organic carbon, water content and nitrous oxide emission in a reclaimed coal mine soil

Science.gov (United States)

Manure-based organic amendments can restore soil quality and allow for intensive sustained biomass production on degraded lands. However the large quantities of nitrogen and organic carbon added with such amendments could create soil conditions favorable for nitrous oxide production and emissions. T...

Data from: Root biomass and exudates link plant diversity with soil bacterial and fungal biomass

NARCIS (Netherlands)

Eisenhauer, Nico; Strecker, Tanja; Lanoue, Arnaud; Scheu, Stefan; Steinauer, Katja; Thakur, Madhav P.; Mommer, L.

2017-01-01

Plant diversity has been shown to determine the composition and functioning of soil biota. Although root-derived organic inputs are discussed as the main drivers of soil communities, experimental evidence is scarce. While there is some evidence that higher root biomass at high plant diversity

The natural radioactivity of soils in The Netherlands

International Nuclear Information System (INIS)

Bannink, D.W.; Keen, A.; Koester, H.W.; Pennders, R.M.J.; Winkel, J.H. de

1986-02-01

Forty percent of the natural radiation exposure of man is caused by the primordial radionuclides - U-238, Th-232 and K-40 - and their daughters in the soil. It is shown that the activity concentrations of these nuclides vary between Dutch soils and that they lie within the normal range reported by the UNSCEAR committee. In linear regression models a clear link was found between the activity concentrations and the following soil properties: grain size distribution, organic matter and lime content, whether or not in combination with soil type. The same models are capable to predict the activity concentrations in various soils with reasonable precision. No improvement of the models was obtained by incorporating the pH and/or sampling depth. Possible further investigations to refine the models are suggested. (Auth.)

Sustainable agriculture, soil management and erosion from prehistoric times to 2100

Science.gov (United States)

Vanwalleghem, Tom; Gómez, Jose Alfonso; Infante Amate, Juan; González Molina, Manuel; Fernández, David Soto; Guzmán, Gema; Vanderlinden, Karl; Laguna, Ana; Giráldez, Juan Vicente

2015-04-01

The rational use of soil requires the selection of management practices to take profit of the beneficial functions of plant growth, water and nutrient storage, and pollutants removal by filtering and decomposition without altering its properties. However, the first evidence of important and widespread erosion peaks can generally be found with the arrival of the first farmers all over the world. In areas with a long land-use history such as the Mediterranean, clear signs indicating the advanced degradation status of the landscape, such as heavily truncated soils, are visible throughout. Soil conservation practices are then aimed at reducing erosion to geological rates, in equilibrium with long-term soil formation rates, while maximizing agricultural production. The adoption of such practices in most areas of the world are as old as the earliest soil erosion episodes themselves. This work firstly reviews historical evidence linking soil management and soil erosion intensity, with examples from N Europe and the Mediterranean. In particular, work by the authors in olive orchards will be presented that shows how significant variations in soil erosion rates between could be linked to the historical soil management. The potential of historical documents for calibrating a soil erosion model is shown as the model, in this case RUSLE-based and combining tillage and water erosion, adequately represents the measured erosion rate dynamics. Secondly, results from present-day, long-term farm experiments in the EU are reviewed to evaluate the effect of different soil management practices on physical soil properties, such as bulk density, penetration resistance, aggregate stability, runoff coefficient or sediment yield. Finally, we reflect upon model and field data that indicate how future global climate change is expected to affect soil management and erosion and how the examples used above hold clues about sustainable historical management practices that can be used successfully

Linking variability in soil solution dissolved organic carbon to climate, soil type, and vegetation type

NARCIS (Netherlands)

Camino-Serrano, Marta; Gielen, Bert; Luyssaert, Sebastiaan; Ciais, Philippe; Vicca, Sara; Guenet, Bertrand; Vos, Bruno De; Cools, Nathalie; Ahrens, Bernhard; Altaf Arain, M.; Borken, Werner; Clarke, Nicholas; Clarkson, Beverley; Cummins, Thomas; Don, Axel; Pannatier, Elisabeth Graf; Laudon, Hjalmar; Moore, Tim; Nieminen, Tiina M.; Nilsson, Mats B.; Peichl, Matthias; Schwendenmann, Luitgard; Siemens, Jan; Janssens, Ivan

2014-01-01

Lateral transport of carbon plays an important role in linking the carbon cycles of terrestrial and aquatic ecosystems. There is, however, a lack of information on the factors controlling one of the main C sources of this lateral flux, i.e., the concentration of dissolved organic carbon (DOC) in

Tracking agricultural soil nitric oxide emission variations with novel isotopic measurements

Science.gov (United States)

Miller, D. J.; Chai, J.; Guo, F.; Overby, S.; Dell, C. J.; Karsten, H.; Hastings, M. G.

2016-12-01

Agricultural production systems impact the reactive nitrogen cycle via atmospheric nitrogen emissions including nitric oxide, denoted as total nitrogen oxides (NOx). NOx serve as precursors to ozone and nitrate aerosols, influencing air quality, radiative forcing, and ecosystem health. With recent declines in fuel combustion sources, soil emissions are an increasing contributor to NOx budgets. However, spatially heterogeneous, episodic soil NOx pulses are challenging to constrain and remain highly uncertain. Using a novel hourly resolution soil flux chamber-based NOx collection method, we investigate fertilizer management and climatic controls on cropland soil NOx flux and nitrogen isotopic composition (δ15N-NOx) natural abundance variations with field-based and laboratory measurements. No-till, rain-fed corn plots were sampled daily (triplicate isotope samples per treatment per day) following broadcast and shallow-disk injected dairy manure applications as part of a sustainable dairy cropping study in State College, PA (Penn State University; USDA-ARS). Injected manure plots exhibited median fluxes two times higher with larger spatial variations than that for broadcast manure. Soil emission δ15N-NOx signatures of -45 to -20 ‰ were correlated with flux magnitudes across both treatments. Median δ15N-NOx signatures for injected manure were lower with larger spatial variations (-32 ± 9 ‰) than that for broadcast manure (-24 ± 1.5 ‰). These differences are likely linked with higher NH4+ availability for nitrification with injected manure in contrast with higher NH3 volatilization and higher soil δ15N-NH4+ for broadcast manure. Although NOx fluxes were suppressed 1-2 days after heavy rainfall (>35 % water-filled pore space), δ15N-NOx remained consistent. Controlled laboratory incubation studies will also be presented quantifying links with inorganic substrate and fertilizer δ15N. Our observations suggest that agricultural soil δ15N-NOx signatures are

Soil and public health: invisible bridges

Science.gov (United States)

Public health institutions, as ancient as civilizations itself, are intrinsically connected with soils. The massive body of the empirical knowledge about this connection has been accumulated. Recently unraveling the underlying mechanisms of this link has begun, and many of them appear to have the m...

Perennial grasses as the ecological link for preserving the fertility of the peat soils polluted by radionuclides

International Nuclear Information System (INIS)

Podolyak, A.G.; Saraseko, E.G.; Arastovich, T.V.; Suzko, O.V.; Tagaj, S.A.; Lasko, T.V.; Goloveshkin, V.V.

2011-01-01

The problem of degradation of peat soils polluted with 137Cs and 90Sr and cultivation of the crop production on them is considered. Distribution of grasslands and pastures on polluted peat soils by the regions of the Republic of Belarus is presented. Characteristics of the peat soils are shown. Coefficients of migration of radionuclides in perennial grasses' hay depending on mobile potassium availability (for 137Cs) and soil reaction pHkci (for 90sr) are evaluated. Inadequacy of the hay, harvested on polluted territories, to the main quality characteristics is presented and analyzed. Crop mixtures recommended for grasslands and pastures reseeding on polluted territories are suggested. The list of cultivars suitable for the conditions of over wetting is offered. It is recommended to use shallow peat soils as grasslands. Permanent cereal grasses restore organic matter of these soils and provide economic efficiency of agricultural use. According the results of the research the transfer factors of 137Cs and 90Sr to plants are relatively low. This fact is explained by the time that has passed since the accident on Chernobyl nuclear power plant and by the variations of mobile potassium and exchangeable acidity in peat soils

Microbial reduction of Fe(III) and turnover of acetate in Hawaiian soils.

Science.gov (United States)

Küsel, Kirsten; Wagner, Christine; Trinkwalter, Tanja; Gössner, Anita S; Bäumler, Rupert; Drake, Harold L

2002-04-01

Soils contain anoxic microzones, and acetate is an intermediate during the turnover of soil organic carbon. Due to negligible methanogenic activities in well-drained soils, acetate accumulates under experimentally imposed short-term anoxic conditions. In contrast to forest, agricultural, and prairie soils, grassland soils from Hawaii rapidly consumed rather than formed acetate when incubated under anoxic conditions. Thus, alternative electron acceptors that might be linked to the anaerobic oxidation of soil organic carbon in Hawaiian soils were assessed. Under anoxic conditions, high amounts of Fe(II) were formed by Hawaiian soils as soon as soils were depleted of nitrate. Rates of Fe(II) formation for different soils ranged from 0.01 to 0.31 micromol (g dry weight soil)(-1) h(-1), but were not positively correlated to increasing amounts of poorly crystallized iron oxides. In general, sulfate-reducing and methanogenic activities were negligible. Supplemental acetate was rapidly oxidized to CO2 via the sequential reduction of nitrate and Fe(III) in grassland soil (obtained near Kaena State Park). Supplemental H2 stimulated the formation of Fe(II), but H2-utilizing acetogens appeared to also be involved in the consumption of H2. Approximately 270 micromol Fe(III) (g dry weight soil)(-1) was available for Fe(III)-reducing bacteria, and acetate became a stable end product when Fe(III) was depleted in long-term incubations. Most-probable-number estimates of H2- and acetate-utilizing Fe(III) reducers and of H2-utilizing acetogens were similar. These results indicate that (i) the microbial reduction of Fe(III) is an important electron-accepting process for the anaerobic oxidation of organic matter in Fe(III)-rich Hawaiian soils of volcanic origin, and (ii) acetate, formed by the combined activity of fermentative and acetogenic bacteria, is an important trophic link in anoxic microsites of these soils.

Assessment of the effectiveness of soil and water conservation measures in reducing runoff and soil loss: establishment of a European database

International Nuclear Information System (INIS)

Maetens, W.; Vanmaercke, M.; Poesen, J.

2009-01-01

Soil erosion by water is recognised as a major soil degradation process that requires a global approach. Large regions all over the world are in need of integrated conservation strategies that sustainable prevent and remediate soil erosion. therefore, quantitative and globally interpretable data are needed in support of models and decision making. the effects of various soil and water conservation techniques (SWCT) on runoff and soil loss in Europe have been extensively studied over the last 60 years. Runoff plots are the most widely used measurement technique to study the effects of SWCT on runoff and soil loss by water erosion. Hence, many data are available. However, the insights gained hereby remain mostly local and often qualitative whereas the full potential of the available data is not exploited yet. This is mainly due to the fragmentation of knowledge and extrapolation difficulties inherently linked with this type of data. (Author) 8 refs.

Linking aboveground net primary productivity to soil carbon and dissolved organic carbon in complex terrain

Science.gov (United States)

F.S. Peterson; K. Lajtha

2013-01-01

Factors influencing soil organic matter (SOM) stabilization and dissolved organic carbon (DOC) content in complex terrain, where vegetation, climate, and topography vary over the scale of a few meters, are not well understood. We examined the spatial correlations of lidar and geographic information system-derived landscape topography, empirically measured soil...

Sustaining "the Genius of Soils"

Science.gov (United States)

Sposito, G.

2011-12-01

Soils are weathered porous earth surficial materials that exhibit an approximately vertical stratification reflecting the continual action of percolating water and living organisms. They are complex open, multicomponent, multiphase biogeochemical systems which function as both provisioning and regulatory agents in terrestrial ecosystems while influencing aquatic ecosystems through their impacts on evapotranspiration and runoff. The ability of soils to engage in their supportive ecosystem functions depends on what has been termed metaphorically as their "natural capital," the defining properties that condition soil response to biological, geological, and hydrological processes as well as human-driven activities. Natural capital must necessarily differ among soils depending on how they have developed under the five soil-forming processes, but it also can be determined by land use and by the flows of matter and energy that link the global atmosphere, biosphere, and hydrosphere. These latter two determinants have in recent decades begun to exhibit strong variability that exceeds what has been characteristic of them during the past 10 millennia of earth history, thereby raising the apocalyptic issue of whether a deleterious or even catastrophic undermining of the ability of soils to function supportively in ecosystems is in the offing. Resolving this issue will require deeper understanding of how soils perform their provisioning and regulatory functions, how they respond to land-use changes, and how they mediate the global flows of matter and energy.

A Dynamic Economic Analysis of Nitrogen-Induced Soil Acidification in China

OpenAIRE

Yang, Ziyan

2015-01-01

This paper studies the environmental value of nitrogen fertilizer in a rapeseed-rice double-crop system in China to address the issue of nitrogen-induced soil acidification in China’s farmland. Previous literature always regarded the acid rain as the most important contributor to soil acidification. Thus, previous literature seldom linked soil quality with nitrogen leaching but studied acidification as a side product of air pollution. However, the latest scientific evidences show that China’s...

Invited presentations. College on soil physics 2003

International Nuclear Information System (INIS)

Gabriels, D.M.; Ghirardi, G.; Nielsen, D.R.; Pla Sentis, I.; Skidmore, E.L.

2004-01-01

The present book is a partial compilation of contributions from selected former participants of the College on Soil Physics invited to make presentations related to their achievements as a result of attending the College. It also serves as a testimony of the existing links between soil physicists throughout the world strengthened by the support and programs of the International Centre for Theoretical Physics originally envisioned by Abdus Salam to foster the growth of advanced studies and physics research in developing countries

Invited presentations. College on soil physics 2003

Energy Technology Data Exchange (ETDEWEB)

Gabriels, D M [Univ. Ghent (Belgium); Ghirardi, G [Univ. Trieste (Italy); Nielsen, D R [Univ. California (United States); Pla Sentis, I [Univ. Lleida (Spain); Skidmore, E L [Kansas State Univ. (United States)

2004-05-15

The present book is a partial compilation of contributions from selected former participants of the College on Soil Physics invited to make presentations related to their achievements as a result of attending the College. It also serves as a testimony of the existing links between soil physicists throughout the world strengthened by the support and programs of the International Centre for Theoretical Physics originally envisioned by Abdus Salam to foster the growth of advanced studies and physics research in developing countries.

Microbial community responses in forest mineral soil to compaction, organic matter removal, and vegetation control

Science.gov (United States)

Matt D. Busse; Samual E. Beattie; Robert F. Powers; Filpe G. Sanchez; Allan E. Tiarks

2006-01-01

We tested three disturbance hypotheses in young conifer plantations: H1: soil compaction and removal of surface organic matter produces sustained changes in microbial community size, activity, and structure in mineral soil; H2: microbial community characteristics in mineral soil are linked to the recovery of plant diversity...

GEOPHYSICAL PROPERTIES OF SOILS

KAUST Repository

Santamarina, Carlos

2016-12-01

Low energy perturbations used in geophysical methods provide insightful information about constant-fabric soil properties and their spatial variability. There are causal links between soil type, index properties, elastic wave velocity, electromagnetic wave parameters and thermal properties. Soil type relates to the stress-dependent S-wave velocity, thermal and electrical conductivity and permittivity. The small strain stiffness reflects the state of stress, the extent of diagenetic cementation and/or freezing. Pore fluid chemistry, fluid phase and changes in either fluid chemistry or phase manifest through electromagnetic measurements. The volumetric water content measured with electromagnetic techniques is the best predictor of porosity if the water saturation is 100%. Changes in water saturation alter the P-wave velocity when Srà100%, the S-wave velocity at intermediate saturations, and the thermal conductivity when the saturation is low Srà0%. Finally, tabulated values suffice to estimate heat capacity and latent heat for engineering design, however thermal conductivity requires measurements under proper field conditions.

Discovering the essence of soil

Science.gov (United States)

Frink, D.

2012-04-01

ancient prebiotic soils. Furthermore, the physiological approach sheds light on the emergence of new soil components (e.g. spodic horizons) as ancient prebiotic soils adapt to a plethora of biotic carbon compounds. Other emergent soil properties and behaviors can be linked to the kinds, frequencies, order and intensities of various ubiquitous pedo-perturbations.

Microbial links between sulfate reduction and metal retention in uranium- and heavy metal-contaminated soil.

Science.gov (United States)

Sitte, Jana; Akob, Denise M; Kaufmann, Christian; Finster, Kai; Banerjee, Dipanjan; Burkhardt, Eva-Maria; Kostka, Joel E; Scheinost, Andreas C; Büchel, Georg; Küsel, Kirsten

2010-05-01

Sulfate-reducing bacteria (SRB) can affect metal mobility either directly by reductive transformation of metal ions, e.g., uranium, into their insoluble forms or indirectly by formation of metal sulfides. This study evaluated in situ and biostimulated activity of SRB in groundwater-influenced soils from a creek bank contaminated with heavy metals and radionuclides within the former uranium mining district of Ronneburg, Germany. In situ activity of SRB, measured by the (35)SO(4)(2-) radiotracer method, was restricted to reduced soil horizons with rates of metals were enriched in the solid phase of the reduced horizons, whereas pore water concentrations were low. X-ray absorption near-edge structure (XANES) measurements demonstrated that approximately 80% of uranium was present as reduced uranium but appeared to occur as a sorbed complex. Soil-based dsrAB clone libraries were dominated by sequences affiliated with members of the Desulfobacterales but also the Desulfovibrionales, Syntrophobacteraceae, and Clostridiales. [(13)C]acetate- and [(13)C]lactate-biostimulated soil microcosms were dominated by sulfate and Fe(III) reduction. These processes were associated with enrichment of SRB and Geobacteraceae; enriched SRB were closely related to organisms detected in soils by using the dsrAB marker. Concentrations of soluble nickel, cobalt, and occasionally zinc declined uranium increased in carbon-amended treatments, reaching metal attenuation and (ii) the fate of uranium mobility is not predictable and may lead to downstream contamination of adjacent ecosystems.

Links between soil properties and steady-state solute transport through cultivated topsoil at the field scale

Science.gov (United States)

Koestel, J. K.; Norgaard, T.; Luong, N. M.; Vendelboe, A. L.; Moldrup, P.; Jarvis, N. J.; Lamandé, M.; Iversen, B. V.; Wollesen de Jonge, L.

2013-02-01

It is known that solute transport through soil is heterogeneous at all spatial scales. However, little data are available to allow quantification of these heterogeneities at the field scale or larger. In this study, we investigated the spatial patterns of soil properties, hydrologic state variables, and tracer breakthrough curves (BTCs) at the field scale for the inert solute transport under a steady-state irrigation rate which produced near-saturated conditions. Sixty-five undisturbed soil columns approximately 20 cm in height and diameter were sampled from the loamy topsoil of an agricultural field site in Silstrup (Denmark) at a sampling distance of approximately 15 m (with a few exceptions), covering an area of approximately 1 ha (60 m × 165 m). For 64 of the 65 investigated soil columns, we observed BTC shapes indicating a strong preferential transport. The strength of preferential transport was positively correlated with the bulk density and the degree of water saturation. The latter suggests that preferential macropore transport was the dominating transport process. Increased bulk densities were presumably related with a decrease in near-saturated hydraulic conductivities and as a consequence to larger water saturation and the activation of larger macropores. Our study provides further evidence that it should be possible to estimate solute transport properties from soil properties such as soil texture or bulk density. We also demonstrated that estimation approaches established for the column scale have to be upscaled when applied to the field scale or larger.

Nitrogen Soil Testing for Corn in Virginia

OpenAIRE

Evanylo, Gregory K.; Alley, Marcus M., 1947-

2009-01-01

An adequate supply of plant-available nitrogen (N) is crucial for efficient corn production, and corn N requirements are greater than any other nutrient. This publication reviews the link between nitrogen and corn production, nitrogen behavior, soil testing, test procedures and recommendations.

Multiscale analysis of depth-dependent soil penetration resistance in a tropical soil

Science.gov (United States)

Paiva De Lima, Renato; Santos, Djail; Medeiros Bezerra, Joel; Machado Siqueira, Glécio; Paz González, Antonio

2013-04-01

Soil penetration resistance (PR) is widely used because it is linked to basic soil properties; it is correlated to root growth and plant production and is also used as a practical tool for assessing soil compaction and to evaluate the effects of soil management. This study investigates how results from multifractal analysis can quantify key elements of depth-dependent PR profiles and how this information can be used at the field scale. We analyzed multifractality of 50 PR vertical profiles, measured from 0 to 40 cm depth and randomly located on a 6.5 ha sugar cane field in north-eastern Brazil. According to the Soil Taxonomy, the studied soil was classified as an Orthic Podsol The scaling property of each profile was typified by singularity and Rényi spectra estimated by the method of moments. The Hurst exponent was used to parameterize the autocorrelation of the vertical PR data sets. Singularity and Rènyi spectra showed the vertical PR data sets exhibited a well-defined multifractal structure. Hurst exponent values were close to one indicating strong persistence in PR variation with soil depth. Also Hurst exponent was negatively and significantly correlated to coefficient of variation (CV) and skewness of the depth-dependent PR. Multifractal analysis added valuable information to describe the spatial arrangement of depth-dependent penetrometer data sets, which was not taken into account by classical statistical indices. Multifractal parameters were mapped over the experimental field and compared with mean, maximum and minimum values of PR; these maps showed the multifractal approach also may complete information provided by descriptive statistics at the field scale.

Reconstruction of food webs in biological soil crusts using metabolomics.

Science.gov (United States)

Baran, Richard; Brodie, Eoin L.; Mayberry-Lewis, Jazmine; Nunes Da Rocha, Ulisses; Bowen, Benjamin P.; Karaoz, Ulas; Cadillo-Quiroz, Hinsby; Garcia-Pichel, Ferran; Northen, Trent R.

2015-04-01

Biological soil crusts (BSCs) are communities of organisms inhabiting the upper layer of soil in arid environments. BSCs persist in a dessicated dormant state for extended periods of time and experience pulsed periods of activity facilitated by infrequent rainfall. Microcoleus vaginatus, a non-diazotrophic filamentous cyanobacterium, is the key primary producer in BSCs in the Colorado Plateau and is an early pioneer in colonizing arid environments. Over decades, BSCs proceed through developmental stages with increasing complexity of constituent microorganisms and macroscopic properties. Metabolic interactions among BSC microorganisms probably play a key role in determining the community dynamics and cycling of carbon and nitrogen. However, these metabolic interactions have not been studied systematically. Towards this goal, exometabolomic analysis was performed using liquid chromatography coupled to tandem mass spectrometry on biological soil crust pore water and spent media of key soil bacterial isolates. Comparison of spent vs. fresh media was used to determine uptake or release of metabolites by specific microbes. To link pore water experiments with isolate studies, metabolite extracts of authentic soil were used as supplements for isolate exometabolomic profiling. Our soil metabolomics methods detected hundreds of metabolites from soils including many novel compounds. Overall, Microcoleus vaginatus was found to release and utilize a broad range of metabolites. Many of these metabolites were also taken up by heterotrophs but there were surprisingly few metabolites uptaken by all isolates. This points to a competition for a small set of central metabolites and specialization of individual heterotrophs towards a diverse pool of available organic nutrients. Overall, these data suggest that understanding the substrate specialization of biological soil crust bacteria can help link community structure to nutrient cycling.

Soil Quality Indicator: a new concept

Science.gov (United States)

Barão, Lúcia; Basch, Gottlieb

2017-04-01

During the last century, cultivated soils have been intensively exploited for food and feed production. This exploitation has compromised the soils' natural functions and many of the soil-mediated ecosystems services, including its production potential for agriculture. Also, soils became increasingly vulnerable and less resilient to a wide range of threats. To overcome this situation, new and better management practices are needed to prevent soil from degradation. However, to adopt the best management practices in a specific location, it is necessary to evaluate the soil quality status first. Different soil quality indicators have been suggested over the last decades in order to evaluate the soil status, and those are often based on the performance of soil chemical, physical and biological properties. However, the direct link between these properties and the associated soil functions or soil vulnerability to threats appears more difficult to be established. This present work is part of the iSQAPER project- Interactive Soil Quality Assessment in Europe and China for Agricultural Productivity and Environmental Resilience, where new soil quality concepts are explored to provide better information regarding the effects of the most promising agricultural management practices on soil quality. We have developed a new conceptual soil quality indicator which determines the soil quality status, regarding its vulnerability towards different threats. First, different indicators were specifically developed for each of the eight threats considered - Erosion, SOM decline, Poor Structure, Poor water holding capacity, Compaction, N-Leaching, Soil-borne pests and diseases and Salinization. As an example for the case of Erosion, the RUSLE equation for the estimate of the soil annual loss was used. Secondly, a reference classification was established for each indicator to integrate all possible results into a Good, Intermediate or Bad classification. Finally, all indicators were

Changes in the Bacterial Community Structure of Remediated Anthracene-Contaminated Soils

Science.gov (United States)

Delgado-Balbuena, Laura; Bello-López, Juan M.; Navarro-Noya, Yendi E.; Rodríguez-Valentín, Analine; Luna-Guido, Marco L.; Dendooven, Luc

2016-01-01

Mixing soil or adding earthworms (Eisenia fetida (Savigny, 1826)) accelerated the removal of anthracene, a polycyclic aromatic hydrocarbon, from a pasture and an arable soil, while a non-ionic surfactant (Surfynol® 485) inhibited the removal of the contaminant compared to the untreated soil. It was unclear if the treatments affected the soil bacterial community and consequently the removal of anthracene. Therefore, the bacterial community structure was monitored by means of 454 pyrosequencing of the 16S rRNA gene in the pasture and arable soil mixed weekly, amended with Surfynol® 485, E. fetida or organic material that served as food for the earthworms for 56 days. In both soils, the removal of anthracene was in the order: mixing soil weekly (100%) > earthworms applied (92%) > organic material applied (77%) > untreated soil (57%) > surfactant applied (34%) after 56 days. There was no clear link between removal of anthracene from soil and changes in the bacterial community structure. On the one hand, application of earthworms removed most of the contaminant from the arable soil and had a strong effect on the bacterial community structure, i.e. a decrease in the relative abundance of the Acidobacteria, Chloroflexi and Gemmatimonadetes, and an increase in that of the Proteobacteria compared to the unamended soil. Mixing the soil weekly removed all anthracene from the arable soil, but had little or no effect on the bacterial community structure. On the other hand, application of the surfactant inhibited the removal of anthracene from the arable soil compared to the untreated soil, but had a strong effect on the bacterial community structure, i.e. a decrease in the relative abundance of Cytophagia (Bacteroidetes), Chloroflexi, Gemmatimonadetes and Planctomycetes and an increase in that of the Flavobacteria (Bacteroidetes) and Proteobacteria. Additionally, the removal of anthracene was similar in the different treatments of both the arable and pasture soil, but the

Changes in the Bacterial Community Structure of Remediated Anthracene-Contaminated Soils.

Directory of Open Access Journals (Sweden)

Laura Delgado-Balbuena

Full Text Available Mixing soil or adding earthworms (Eisenia fetida (Savigny, 1826 accelerated the removal of anthracene, a polycyclic aromatic hydrocarbon, from a pasture and an arable soil, while a non-ionic surfactant (Surfynol® 485 inhibited the removal of the contaminant compared to the untreated soil. It was unclear if the treatments affected the soil bacterial community and consequently the removal of anthracene. Therefore, the bacterial community structure was monitored by means of 454 pyrosequencing of the 16S rRNA gene in the pasture and arable soil mixed weekly, amended with Surfynol® 485, E. fetida or organic material that served as food for the earthworms for 56 days. In both soils, the removal of anthracene was in the order: mixing soil weekly (100% > earthworms applied (92% > organic material applied (77% > untreated soil (57% > surfactant applied (34% after 56 days. There was no clear link between removal of anthracene from soil and changes in the bacterial community structure. On the one hand, application of earthworms removed most of the contaminant from the arable soil and had a strong effect on the bacterial community structure, i.e. a decrease in the relative abundance of the Acidobacteria, Chloroflexi and Gemmatimonadetes, and an increase in that of the Proteobacteria compared to the unamended soil. Mixing the soil weekly removed all anthracene from the arable soil, but had little or no effect on the bacterial community structure. On the other hand, application of the surfactant inhibited the removal of anthracene from the arable soil compared to the untreated soil, but had a strong effect on the bacterial community structure, i.e. a decrease in the relative abundance of Cytophagia (Bacteroidetes, Chloroflexi, Gemmatimonadetes and Planctomycetes and an increase in that of the Flavobacteria (Bacteroidetes and Proteobacteria. Additionally, the removal of anthracene was similar in the different treatments of both the arable and pasture soil

Linking precipitation, evapotranspiration and soil moisture content for the improvement of predictability over land

Science.gov (United States)

Catalano, Franco; Alessandri, Andrea; De Felice, Matteo

2013-04-01

Climate change scenarios are expected to show an intensification of the hydrological cycle together with modifications of evapotranspiration and soil moisture content. Evapotranspiration changes have been already evidenced for the end of the 20th century. The variance of evapotranspiration has been shown to be strongly related to the variance of precipitation over land. Nevertheless, the feedbacks between evapotranspiration, soil moisture and precipitation have not yet been completely understood at present-day. Furthermore, soil moisture reservoirs are associated to a memory and thus their proper initialization may have a strong influence on predictability. In particular, the linkage between precipitation and soil moisture is modulated by the effects on evapotranspiration. Therefore, the investigation of the coupling between these variables appear to be of primary importance for the improvement of predictability over the continents. The coupled manifold (CM) technique (Navarra and Tribbia 2005) is a method designed to separate the effects of the variability of two variables which are connected. This method has proved to be successful for the analysis of different climate fields, like precipitation, vegetation and sea surface temperature. In particular, the coupled variables reveal patterns that may be connected with specific phenomena, thus providing hints regarding potential predictability. In this study we applied the CM to recent observational datasets of precipitation (from CRU), evapotranspiration (from GIMMS and MODIS satellite-based estimates) and soil moisture content (from ESA) spanning a time period of 23 years (1984-2006) with a monthly frequency. Different data stratification (monthly, seasonal, summer JJA) have been employed to analyze the persistence of the patterns and their characteristical time scales and seasonality. The three variables considered show a significant coupling among each other. Interestingly, most of the signal of the

Nitrogen as a regulatory factor of methane oxidation in soils and sediments

NARCIS (Netherlands)

Bodelier, P.L.E.; Laanbroek, H.J.

2004-01-01

The oxidation of methane by methane-oxidising microorganisms is an important link in the global methane budget. Oxic soils are a net sink while wetland soils are a net source of atmospheric methane. It has generally been accepted that the consumption of methane in upland as well as lowland systems

Intraspecific plant-soil feedback as a mechanism underlying invasiveness of neophytes of the Czech Republic

OpenAIRE

Knobová, Pavlína

2017-01-01

Intraspecific plant-soil feedback is a relationship in which plant affects the composition of the soil and such modified soil affects growth of the same plant species. This relationship and its intensity may be linked with plant dominance and invasiveness. Dominant species can alter the composition of the soil in their favor and thus show positive intraspecific plant-soil feedback. As the invasive species are commonly being dominant in their new environment, it can be expected that intraspeci...

Distribution of cadmium among geochemical fractions in floodplain soils of progressing development

International Nuclear Information System (INIS)

Lair, G.J.; Graf, M.; Zehetner, F.; Gerzabek, M.H.

2008-01-01

Initial soil development in river floodplains influences soil properties and processes. In this study, suites of young floodplain soils sampled at three European rivers (Danube/Austria, Ebro/Spain and Elbe/Germany) were used to link soil development to the soils' retention capacity for cadmium. Geochemichal fractionation of original and metal-spiked soils was conducted. Cadmium remained in weakly bound fractions in both original and spiked soils, representing an entirely different behaviour than observed for copper in an earlier study. The tendency of incorporation into more stable forms over time was only slightly expressed. Correlation analysis revealed the involvement of different sorption surfaces in soil, with no single soil constituent determining cadmium retention behaviour. Nevertheless, in the calcareous soils of the Danube floodplain, we found increased cadmium retention and decreased portions of desorbable cadmium with progressing soil development. - Distribution of cadmium among geochemical fractions in floodplain soils reveals high mobility but increased retention capacity with increasing soil age and development

Linking particle and pore-size distribution parameters to soil gas transport properties

DEFF Research Database (Denmark)

Arthur, Emmanuel; Møldrup, Per; Schjønning, Per

2012-01-01

, respectively) and the Campbell water retention parameter b were used to characterize particle and pore size distributions, respectively. Campbell b yielded a wide interval (4.6–26.2) and was highly correlated with α, β, and volumetric clay content. Both Dp/Do and ka followed simple power-law functions (PLFs......) of air-filled porosity (εa). The PLF tortuosity–connectivity factors (X*) for Dp/Do and ka were both highly correlated with all basic soil characteristics, in the order of volumetric clay content = Campbell b > gravimetric clay content > α > β. The PLF water blockage factors (H) for Dp/Do and ka were...... also well (but relatively more weakly) correlated with the basic soil characteristics, again with the best correlations to volumetric clay content and b. As a first attempt at developing a simple Dp/Do model useful at the field scale, we extended the classical Buckingham Dp/Do model (εa2) by a scaling...

Soil Organic Matter Stabilization via Mineral Interactions in Forest Soils with Varying Saturation Frequency

Science.gov (United States)

Possinger, A. R.; Inagaki, T.; Bailey, S. W.; Kogel-Knabner, I.; Lehmann, J.

2017-12-01

Soil carbon (C) interaction with minerals and metals through surface adsorption and co-precipitation processes is important for soil organic C (SOC) stabilization. Co-precipitation (i.e., the incorporation of C as an "impurity" in metal precipitates as they form) may increase the potential quantity of mineral-associated C per unit mineral surface compared to surface adsorption: a potentially important and as yet unaccounted for mechanism of C stabilization in soil. However, chemical, physical, and biological characterization of co-precipitated SOM as such in natural soils is limited, and the relative persistence of co-precipitated C is unknown, particularly under dynamic environmental conditions. To better understand the relationships between SOM stabilization via organometallic co-precipitation and environmental variables, this study compares mineral-SOM characteristics across a forest soil (Spodosol) hydrological gradient with expected differences in co-precipitation of SOM with iron (Fe) and aluminum (Al) due to variable saturation frequency. Soils were collected from a steep, well-drained forest soil transect with low, medium, and high frequency of water table intrusion into surface soils (Hubbard Brook Experimental Forest, Woodstock, NH). Lower saturation frequency soils generally had higher C content, C/Fe, C/Al, and other indicators of co-precipitation interactions resulting from SOM complexation, transport, and precipitation, an important process of Spodosol formation. Preliminary Fe X-ray Absorption Spectroscopic (XAS) characterization of SOM and metal chemistry in low frequency profiles suggest co-precipitation of SOM in the fine fraction (soils showed greater SOC mineralization per unit soil C for low saturation frequency (i.e., higher co-precipitation) soils; however, increased mineralization may be attributed to non-mineral associated fractions of SOM. Further work to identify the component of SOM contributing to rapid mineralization using 13C

Taxonomically-linked growth phenotypes during arsenic stress among arsenic resistant bacteria isolated from soils overlying the Centralia coal seam fire.

Science.gov (United States)

Dunivin, Taylor K; Miller, Justine; Shade, Ashley

2018-01-01

Arsenic (As), a toxic element, has impacted life since early Earth. Thus, microorganisms have evolved many As resistance and tolerance mechanisms to improve their survival outcomes given As exposure. We isolated As resistant bacteria from Centralia, PA, the site of an underground coal seam fire that has been burning since 1962. From a 57.4°C soil collected from a vent above the fire, we isolated 25 unique aerobic As resistant bacterial strains spanning seven genera. We examined their diversity, resistance gene content, transformation abilities, inhibitory concentrations, and growth phenotypes. Although As concentrations were low at the time of soil collection (2.58 ppm), isolates had high minimum inhibitory concentrations (MICs) of arsenate and arsenite (>300 mM and 20 mM respectively), and most isolates were capable of arsenate reduction. We screened isolates (PCR and sequencing) using 12 published primer sets for six As resistance genes (AsRGs). Genes encoding arsenate reductase (arsC) and arsenite efflux pumps (arsB, ACR3(2)) were present, and phylogenetic incongruence between 16S rRNA genes and AsRGs provided evidence for horizontal gene transfer. A detailed investigation of differences in isolate growth phenotypes across As concentrations (lag time to exponential growth, maximum growth rate, and maximum OD590) showed a relationship with taxonomy, providing information that could help to predict an isolate's performance given As exposure in situ. Our results suggest that microbiological management and remediation of environmental As could be informed by taxonomically-linked As tolerance, potential for resistance gene transferability, and the rare biosphere.

Organic carbon stocks and sequestration rates of forest soils in Germany.

Science.gov (United States)

Grüneberg, Erik; Ziche, Daniel; Wellbrock, Nicole

2014-08-01

The National Forest Soil Inventory (NFSI) provides the Greenhouse Gas Reporting in Germany with a quantitative assessment of organic carbon (C) stocks and changes in forest soils. Carbon stocks of the organic layer and the mineral topsoil (30 cm) were estimated on the basis of ca. 1.800 plots sampled from 1987 to 1992 and resampled from 2006 to 2008 on a nationwide grid of 8 × 8 km. Organic layer C stock estimates were attributed to surveyed forest stands and CORINE land cover data. Mineral soil C stock estimates were linked with the distribution of dominant soil types according to the Soil Map of Germany (1 : 1 000 000) and subsequently related to the forest area. It appears that the C pool of the organic layer was largely depending on tree species and parent material, whereas the C pool of the mineral soil varied among soil groups. We identified the organic layer C pool as stable although C was significantly sequestered under coniferous forest at lowland sites. The mineral soils, however, sequestered 0.41 Mg C ha(-1) yr(-1) . Carbon pool changes were supposed to depend on stand age and forest transformation as well as an enhanced biomass input. Carbon stock changes were clearly attributed to parent material and soil groups as sandy soils sequestered higher amounts of C, whereas clayey and calcareous soils showed small gains and in some cases even losses of soil C. We further showed that the largest part of the overall sample variance was not explained by fine-earth stock variances, rather by the C concentrations variance. The applied uncertainty analyses in this study link the variability of strata with measurement errors. In accordance to other studies for Central Europe, the results showed that the applied method enabled a reliable nationwide quantification of the soil C pool development for a certain period. © 2014 The Authors. Global Change Biology Published by John Wiley & Sons Ltd.

Soil Plant and plant mammal transfer factors

NARCIS (Netherlands)

de Nijs ACM; Vermeire TG

1990-01-01

In order to assess the lifetime hazard of ingestion exposure of man to new substances, the RIVM Assessment System for New Substances links environmental concentrations in water and soil to human exposure applying transfer factors. This report discusses indirect human exposure to new substances via

Characterization for Soil Fixation by Polyelectrolyte Complex

Energy Technology Data Exchange (ETDEWEB)

Choi, Yong Suk; Kwon, Sang Woon; Yang, Heeman; Lee, Kune Woo; Seo, Bumkyoung; Moon, Jei Kwon [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

2014-05-15

According to report, the radioactivity bulk (approx. 95%) is localized within topsoil. Therefore soil surface on topsoil should be fixed to prevent the spreading of the contaminated soils with Cs-137 by wind and water erosion. Many methods have been developing for soil fixation to remove radioactive contaminants in soil and prevent to diffuse radioactive materials. Various materials have been also used as fixatives such as clays, molecular sieves, polymer, and petroleum based products. One of the methods is a soil fixation or solidification using polyelectrolyte. Polyelectrolytes have many ionic groups and make into the polyelectrolyte complex (PEC) due to electrostatic interaction of polyanion and polycation in an aqueous solution. It can be avoids using the chemical cross-linking agents, and reducing the possible toxicity and other undesirable effects of the reagents. PEC can fix soil particles by flocculation and formation of crust between soil. The method can also prevent a spread of radioactive material by floating on a soil surface. Recently, PEC used for the solidification of soil near the Fukushima nuclear power plant in Japan. The decontamination efficiency of the surface soils reached 90%, and dust release was effectively suppressed during the removal of surface soils. In this study, it was investigated the fixation of the soil by PEC to avoid the spread of the contamination in addition to the separation of soil and PEC. The physicochemical properties of polyelectrolyte complex solution and the stability of fixed soil by PEC were investigated. The mode of the addition is important to prepare the polyelectrolytes complex without PAA agglomerate. The concentration of salt in the polyelectrolyte complex solution is a very important parameter for the soil fixation.

Characterization for Soil Fixation by Polyelectrolyte Complex

International Nuclear Information System (INIS)

Choi, Yong Suk; Kwon, Sang Woon; Yang, Heeman; Lee, Kune Woo; Seo, Bumkyoung; Moon, Jei Kwon

2014-01-01

According to report, the radioactivity bulk (approx. 95%) is localized within topsoil. Therefore soil surface on topsoil should be fixed to prevent the spreading of the contaminated soils with Cs-137 by wind and water erosion. Many methods have been developing for soil fixation to remove radioactive contaminants in soil and prevent to diffuse radioactive materials. Various materials have been also used as fixatives such as clays, molecular sieves, polymer, and petroleum based products. One of the methods is a soil fixation or solidification using polyelectrolyte. Polyelectrolytes have many ionic groups and make into the polyelectrolyte complex (PEC) due to electrostatic interaction of polyanion and polycation in an aqueous solution. It can be avoids using the chemical cross-linking agents, and reducing the possible toxicity and other undesirable effects of the reagents. PEC can fix soil particles by flocculation and formation of crust between soil. The method can also prevent a spread of radioactive material by floating on a soil surface. Recently, PEC used for the solidification of soil near the Fukushima nuclear power plant in Japan. The decontamination efficiency of the surface soils reached 90%, and dust release was effectively suppressed during the removal of surface soils. In this study, it was investigated the fixation of the soil by PEC to avoid the spread of the contamination in addition to the separation of soil and PEC. The physicochemical properties of polyelectrolyte complex solution and the stability of fixed soil by PEC were investigated. The mode of the addition is important to prepare the polyelectrolytes complex without PAA agglomerate. The concentration of salt in the polyelectrolyte complex solution is a very important parameter for the soil fixation

Uncertainty indication in soil function maps - transparent and easy-to-use information to support sustainable use of soil resources

Science.gov (United States)

Greiner, Lucie; Nussbaum, Madlene; Papritz, Andreas; Zimmermann, Stephan; Gubler, Andreas; Grêt-Regamey, Adrienne; Keller, Armin

2018-05-01

Spatial information on soil function fulfillment (SFF) is increasingly being used to inform decision-making in spatial planning programs to support sustainable use of soil resources. Soil function maps visualize soils abilities to fulfill their functions, e.g., regulating water and nutrient flows, providing habitats, and supporting biomass production based on soil properties. Such information must be reliable for informed and transparent decision-making in spatial planning programs. In this study, we add to the transparency of soil function maps by (1) indicating uncertainties arising from the prediction of soil properties generated by digital soil mapping (DSM) that are used for soil function assessment (SFA) and (2) showing the response of different SFA methods to the propagation of uncertainties through the assessment. For a study area of 170 km2 in the Swiss Plateau, we map 10 static soil sub-functions for agricultural soils for a spatial resolution of 20 × 20 m together with their uncertainties. Mapping the 10 soil sub-functions using simple ordinal assessment scales reveals pronounced spatial patterns with a high variability of SFF scores across the region, linked to the inherent properties of the soils and terrain attributes and climate conditions. Uncertainties in soil properties propagated through SFA methods generally lead to substantial uncertainty in the mapped soil sub-functions. We propose two types of uncertainty maps that can be readily understood by stakeholders. Cumulative distribution functions of SFF scores indicate that SFA methods respond differently to the propagated uncertainty of soil properties. Even where methods are comparable on the level of complexity and assessment scale, their comparability in view of uncertainty propagation might be different. We conclude that comparable uncertainty indications in soil function maps are relevant to enable informed and transparent decisions on the sustainable use of soil resources.

Slow reaction of soil structure to conservation agriculture practices in Veneto silty soils (North-Easter Italy)

Science.gov (United States)

Piccoli, Ilaria; Camarotto, Carlo; Lazzaro, Barbara; Furlan, Lorenzo; Morari, Francesco

2017-04-01

Soil structure plays a pivotal role in soil functioning and can inform of the degradation of the soil ecosystem. Intensive and repeated tillage operations have been known to negatively affect the soil structure characteristics while conservation agriculture (CA) practices were demonstrated to improve soil structure and related ecosystem services. The aim of this study is to evaluate the effect of conservation agriculture practices on total porosity, pore size distribution, pore architecture and morphology on silty soils of Veneto low-lying plain (North-Eastern Italy). Experimental design was established in 2010 on 4 farms in North-Eastern Italy to compare conventional intensive tillage system "IT" versus conservation agriculture "CA" (no-tillage, cover-crop and residue retention). 96 samples were collected in 2015 at four depths down to 50 cm depth, and investigated for porosity from micro to macro by coupling mercury intrusion porosimetry (MIP) (0.0074-100 µm) and x-ray computed microtomography (µCT) (>26 µm). Pore morphology and architecture were studied from 3D images analysis and MIP pore size curve. Ultramicroporosity class (0.1-5 μm) positively responded to CA after 5-yr of practices adoption while no significant effects were observed in the x-ray µCT domain (> 26 µm). Silty soils of Veneto plain showed a slow reaction to conservation agriculture because of the low soil organic carbon content and poor aggregate stability. Nevertheless the positive influence of CA on ultramicroporosity, which is strictly linked to soil organic carbon (SOC) stabilization, indicated that a virtuous cycle was initiated between SOC and porosity, hopefully leading to well-developed macropore systems and, in turn, enhanced soil functions and ecosystem services.

Rice production in relation to soil quality under different rice-based cropping systems

Science.gov (United States)

Tran Ba, Linh; Sleutel, Steven; Nguyen Van, Qui; Thi, Guong Vo; Le Van, Khoa; Cornelis, Wim

2016-04-01

Soil quality of shallow paddy soils may be improved by introducing upland crops and thus a more diverse crop cultivation pattern. Yet, the causal relationship between crop performance and enhanced soil traits in rice-upland crop rotations remains elusive. The objectives of this study were to (i) find correlations among soil properties under different rice-upland crop systems and link selected soil properties to rice growth and yield, (ii) present appropriate values of soil parameters for sustainable rice productivity in heavy clay soil, (iii) evaluate the effect of rotating rice with upland crops on rice yield and economic benefit in a long-term experiment. A rice-upland crop rotational field experiment in the Vietnamese Mekong delta was conducted for 10 years using a randomized complete block design with four treatments and four replications. Treatments were: (i) rice-rice-rice (control - conventional system as farmers' practice), (ii) rice-maize-rice, (iii) rice-mung bean-rice, and (iv) rice-mung bean-maize. Soil and plant sampling were performed after harvest of the rice crop at the end of the final winter-spring cropping season (i.e. year 10). Results show differences in rice growth and yield, and economic benefit as an effect of the crop rotation system. These differences were linked with changes in bulk density, soil porosity, soil aggregate stability index, soil penetration resistance, soil macro-porosity, soil organic carbon, acid hydrolysable soil C and soil nutrient elements, especially at soil depth of 20-30 cm. This is evidenced by the strong correlation (P < 0.01) between rice plant parameters, rice yield and soil properties such as bulk density, porosity, penetration resistance, soil organic carbon and Chydrolysable. It turned out that good rice root growth and rice yield corresponded to bulk density values lower than 1.3 Mg m-3, soil porosity higher than 50%, penetration resistance below 1.0 MPa, and soil organic carbon above 25 g kg-1. The optimal

Relations between soil hydraulic properties and burn severity

NARCIS (Netherlands)

Moody, J.A.; Ebel, B.A.; Stoof, C.R.; Nyman, P.; Martin, D.A.; McKinley, R.

2016-01-01

Wildfire can affect soil hydraulic properties, often resulting in reduced infiltration. The magnitude of change in infiltration varies depending on the burn severity. Quantitative approaches to link burn severity with changes in infiltration are lacking. This study uses controlled laboratory

Investigating soil moisture-climate interactions with prescribed soil moisture experiments: an assessment with the Community Earth System Model (version 1.2)

Science.gov (United States)

Hauser, Mathias; Orth, René; Seneviratne, Sonia I.

2017-04-01

Land surface hydrology is an important control of surface weather and climate. A valuable technique to investigate this link is the prescription of soil moisture in land surface models, which leads to a decoupling of the atmosphere and land processes. Diverse approaches to prescribe soil moisture, as well as different prescribed soil moisture conditions have been used in previous studies. Here, we compare and assess four methodologies to prescribe soil moisture and investigate the impact of two different estimates of the climatological seasonal cycle used to prescribe soil moisture. Our analysis shows that, though in appearance similar, the different approaches require substantially different long-term moisture inputs and lead to different temperature signals. The smallest influence on temperature and the water balance is found when prescribing the median seasonal cycle of deep soil liquid water, whereas the strongest signal is found when prescribing soil liquid and soil ice using the mean seasonal cycle. These results indicate that induced net water-balance perturbations in experiments investigating soil moisture-climate coupling are important contributors to the climate response, in addition to the intended impact of the decoupling. These results help to guide the set-up of future experiments prescribing soil moisture, as for instance planned within the Land Surface, Snow and Soil Moisture Model Intercomparison Project (LS3MIP).

IMPACTOS DA QUEIMA SOBRE ATRIBUTOS QUÍMICOS, FÍSICOS E BIOLÓGICOS DO SOLO

Directory of Open Access Journals (Sweden)

Marciel Redin

2011-01-01

Full Text Available The aim of this study was to verify through literature review the possible impacts of the use of fire on physical, chemical and biological attributes of soil. In relation to physical attributes, the fire may cause a decrease in the volume of macropores, the size of aggregates, the rate of infiltration of water into the soil and consequently its humidity, and an increase in the resistance to penetration of roots and soil density. Moreover, the soil becomes more susceptible to erosive process due to the removal of its vegetation cover. As for the chemical attributes, many studies focusing on chemical properties have reported an increase in levels of N, P, Ca, Mg, among others mineralized nutrients after the passage of fire because the ashes have high concentrations of those nutrients. Burning also reduces the input of organic matter and therefore alters the carbon cycle, contributing to the emission of greenhouse gases into the atmosphere. In relation to biological attributes, the action of flame fire reduces the availability of food (energy supply for microorganisms, mainly reducing the population of mesofauna soil. In general, from the works reviewed, it appears that both the burning of pastures and natural fields as well as crop residues and forest areas, should be avoided as a routine practice, because in general, it directly or indirectly degrades the soil. However, depending on the situation and the production system, burning may be an option the be considered.

Suppression of hyphal growth of soil-borne fungi by dune soils from vigorous and declining stands of Ammophila arenaria

NARCIS (Netherlands)

De Boer, W.; Klein Gunnewiek, P.J.A.; Woldendorp, J.W.

1998-01-01

A study was carried out to determine whether expansion of marram-grass stands (Ammophila arenaria (L.) Link) on acidic inner Dutch coastal dunes was caused by suppressiveness of soils from these stands against three potential pathogenic fungi of marram grass, namely Fusarium culmorum (W. G. Sm.)

Contaminant Gradients in Trees: Directional Tree Coring Reveals Boundaries of Soil and Soil-Gas Contamination with Potential Applications in Vapor Intrusion Assessment.

Science.gov (United States)

Wilson, Jordan L; Samaranayake, V A; Limmer, Matthew A; Schumacher, John G; Burken, Joel G

2017-12-19

Contaminated sites pose ecological and human-health risks through exposure to contaminated soil and groundwater. Whereas we can readily locate, monitor, and track contaminants in groundwater, it is harder to perform these tasks in the vadose zone. In this study, tree-core samples were collected at a Superfund site to determine if the sample-collection location around a particular tree could reveal the subsurface location, or direction, of soil and soil-gas contaminant plumes. Contaminant-centroid vectors were calculated from tree-core data to reveal contaminant distributions in directional tree samples at a higher resolution, and vectors were correlated with soil-gas characterization collected using conventional methods. Results clearly demonstrated that directional tree coring around tree trunks can indicate gradients in soil and soil-gas contaminant plumes, and the strength of the correlations were directly proportionate to the magnitude of tree-core concentration gradients (spearman's coefficient of -0.61 and -0.55 in soil and tree-core gradients, respectively). Linear regression indicates agreement between the concentration-centroid vectors is significantly affected by in planta and soil concentration gradients and when concentration centroids in soil are closer to trees. Given the existing link between soil-gas and vapor intrusion, this study also indicates that directional tree coring might be applicable in vapor intrusion assessment.

Thinking and Countermeasures for Rational Utilization of Soil Fertility in Modern Agriculture Developping

Directory of Open Access Journals (Sweden)

WENG Bo-qi

2014-02-01

Full Text Available Soil is not only an important foundation for agricultural production, but also is the safeguard of human survival. Soil quality is close-ly related with food safety and argo-ecological environment. Soil fertility is the support of modern agricultural development. Multiple disci-plines and specialties are involved in researches of soil cultivating process. Nowadays, the understanding of soil fertility has changed from a-gricultural production to environmental security and resource exploitation, even larger scales to ecological health and global soil change. In this review, the characteristics and inherent link between soil and agriculture were comprehensive expounded from the aspects of long-term fertilization trials, soil cultivation techniques, and modern agriculture development. The challenge and prospect faced in soil science research field were also analyzed. Finally, several suggestions and countermeasures were proposed to the researches of soil science in future.

Changes in soil moisture drive soil methane uptake along a fire regeneration chronosequence in a eucalypt forest landscape.

Science.gov (United States)

Fest, Benedikt; Wardlaw, Tim; Livesley, Stephen J; Duff, Thomas J; Arndt, Stefan K

2015-11-01

Disturbance associated with severe wildfires (WF) and WF simulating harvest operations can potentially alter soil methane (CH4 ) oxidation in well-aerated forest soils due to the effect on soil properties linked to diffusivity, methanotrophic activity or changes in methanotrophic bacterial community structure. However, changes in soil CH4 flux related to such disturbances are still rarely studied even though WF frequency is predicted to increase as a consequence of global climate change. We measured in-situ soil-atmosphere CH4 exchange along a wet sclerophyll eucalypt forest regeneration chronosequence in Tasmania, Australia, where the time since the last severe fire or harvesting disturbance ranged from 9 to >200 years. On all sampling occasions, mean CH4 uptake increased from most recently disturbed sites (9 year) to sites at stand 'maturity' (44 and 76 years). In stands >76 years since disturbance, we observed a decrease in soil CH4 uptake. A similar age dependency of potential CH4 oxidation for three soil layers (0.0-0.05, 0.05-0.10, 0.10-0.15 m) could be observed on incubated soils under controlled laboratory conditions. The differences in soil CH4 uptake between forest stands of different age were predominantly driven by differences in soil moisture status, which affected the diffusion of atmospheric CH4 into the soil. The observed soil moisture pattern was likely driven by changes in interception or evapotranspiration with forest age, which have been well described for similar eucalypt forest systems in south-eastern Australia. Our results imply that there is a large amount of variability in CH4 uptake at a landscape scale that can be attributed to stand age and soil moisture differences. An increase in severe WF frequency in response to climate change could potentially increase overall forest soil CH4 sinks. © 2015 John Wiley & Sons Ltd.

Field assessment of soil structural quality - a development of the Peerlkamp test

DEFF Research Database (Denmark)

Ball, B C; Batey, T; Munkholm, Lars Juhl

2007-01-01

properties (bulk density, penetration resistance and porosity) and crop growth. Indicative thresholds of soil management are suggested. The assessment should be viewed as complementary to conventional laboratory assessments of soil structure. Visual soil structure assessment can indicate to the soil......Increased awareness of the role of soil structure in defining the physical fertility or quality of soil has led to the need for a simple assessment relevant to the environmental and economic sustainability of soil productivity. A test is required that is usable by farmer, consultant and researcher...... alike. Here an assessment of soil structure quality (Sq) is described which is based on a visual key linked to criteria chosen to be as objective as possible. The influences of operator, tillage and crop type on Sq value were tested. The test takes 5-15 min per location and enough replicates were...

Tracking Water, C, N, and P by Linking Local Scale Soil Hydrologic and Biogeochemical Features to Watershed Scale

Science.gov (United States)

Sedaghatdoost, A.; Mohanty, B.; Huang, Y.

2017-12-01

The biogeochemical cycles of carbon (C), nitrogen (N), and phosphorus (P) have many contemporary significance due to their critical roles in determining the structure and function of ecosystems. The objectives of our study is to find out temporal dynamics and spatial distribution of soil physical, chemical, and biological properties and their interaction with C, N, and P cycles in the soil for different land covers and weather conditions. The study is being conducted at three locations within Texas Water Observatory (TWO), including Riesel (USDA-ARS experimental watersheds), Texas A&M Agrilife Research Farm, and Danciger forest in Texas. Soil physical, hydraulic, chemical (total C, total N, total P, pH, EC, redox potential, N-NO3-, N-NH4+, PO42-, K, Ca, Mg, Na, Mn, and Alox and Feox), and microbiological (Microbial biomass C, N, and P, PLFA analysis, enzymatic activity) properties are being measured in the top 30 cm of the soil profile. Our preliminary data shows that biogeochemical processes would be more profound in the areas with higher temperature and precipitation as these factors stimulate microbial activity and thus influence C, N, and P cycles. Also concentrations of C and N are greater in woodlands relative to remnant grasslands as a consequence of the greater above- and below-ground productivity of woodlands relative to remnant grasslands. We hypothesize that finer soil textures have more organic matter, microbial population, and reactive surfaces for chemicals than coarse soils, as described in some recent literature. However, the microbial activity may not be active in fine textured soils as organic materials may be sorbed to clay surfaces or protected from decomposing organisms. We also expect reduced condition in saturated soils which will decrease carbon mineralization while increase denitrification and alkalinity in the soil. Spatio-temporal data with initial evaluation of biogeochemical factors/processes for different land covers will be presented.

Microbial links between sulfate reduction and metal retention in uranium- and heavy metal-contaminated soil

DEFF Research Database (Denmark)

Sitte, Jana; Akob, Denise M.; Kaufmann, Christian

2010-01-01

Sulfate-reducing bacteria (SRB) can affect metal mobility either directly by reductive transformation of metal ions, e.g., uranium, into their insoluble forms or indirectly by formation of metal sulfides. This study evaluated in situ and biostimulated activity of SRB in groundwater-influenced soils...... from a creek bank contaminated with heavy metals and radionuclides within the former uranium mining district of Ronneburg, Germany. In situ activity of SRB, measured by the 35SO42– radiotracer method, was restricted to reduced soil horizons with rates of 142 ± 20 nmol cm–3 day–1. Concentrations...... of heavy metals were enriched in the solid phase of the reduced horizons, whereas pore water concentrations were low. X-ray absorption near-edge structure (XANES) measurements demonstrated that 80% of uranium was present as reduced uranium but appeared to occur as a sorbed complex. Soil-based dsrAB clone...

Uncertainty indication in soil function maps – transparent and easy-to-use information to support sustainable use of soil resources

Directory of Open Access Journals (Sweden)

L. Greiner

2018-05-01

Full Text Available Spatial information on soil function fulfillment (SFF is increasingly being used to inform decision-making in spatial planning programs to support sustainable use of soil resources. Soil function maps visualize soils abilities to fulfill their functions, e.g., regulating water and nutrient flows, providing habitats, and supporting biomass production based on soil properties. Such information must be reliable for informed and transparent decision-making in spatial planning programs. In this study, we add to the transparency of soil function maps by (1 indicating uncertainties arising from the prediction of soil properties generated by digital soil mapping (DSM that are used for soil function assessment (SFA and (2 showing the response of different SFA methods to the propagation of uncertainties through the assessment. For a study area of 170 km2 in the Swiss Plateau, we map 10 static soil sub-functions for agricultural soils for a spatial resolution of 20 × 20 m together with their uncertainties. Mapping the 10 soil sub-functions using simple ordinal assessment scales reveals pronounced spatial patterns with a high variability of SFF scores across the region, linked to the inherent properties of the soils and terrain attributes and climate conditions. Uncertainties in soil properties propagated through SFA methods generally lead to substantial uncertainty in the mapped soil sub-functions. We propose two types of uncertainty maps that can be readily understood by stakeholders. Cumulative distribution functions of SFF scores indicate that SFA methods respond differently to the propagated uncertainty of soil properties. Even where methods are comparable on the level of complexity and assessment scale, their comparability in view of uncertainty propagation might be different. We conclude that comparable uncertainty indications in soil function maps are relevant to enable informed and transparent decisions on the sustainable use of soil

Towards Integrating Soil Quality Monitoring Targets as Measures of Soil Natural Capital Stocks with the Provision of Ecosystem Services

Science.gov (United States)

Taylor, M. D.; Mackay, A. D.; Dominati, E.; Hill, R. B.

2012-04-01

This paper presents the process used to review soil quality monitoring in New Zealand to better align indicators and indicator target ranges with critical values of change in soil function. Since its inception in New Zealand 15 year ago, soil quality monitoring has become an important state of the environment reporting tool for Regional Councils. This tool assists councils to track the condition of soils resources, assess the impact of different land management practices, and provide timely warning of emerging issues to allow early intervention and avoid irreversible loss of natural capital stocks. Critical to the effectiveness of soil quality monitoring is setting relevant, validated thresholds or target ranges. Provisional Target Ranges were set in 2003 using expert knowledge available and data on production responses. Little information was available at that time for setting targets for soil natural capital stocks other than those for food production. The intention was to revise these provisional ranges as further information became available and extend target ranges to cover the regulating and cultural services provided by soils. A recently developed ecosystems service framework was used to explore the feasibility of linking soil natural capital stocks measured by the current suite of soil quality indicators to the provision of ecosystem services by soils. Importantly the new approach builds on and utilises the time series data sets collected by current suite of soil quality indicators, adding value to the current effort, and has the potential to set targets ranges based on the economic and environmental outcomes required for a given farm, catchment or region. It is now timely to develop a further group of environmental indicators for measuring specific soil issues. As with the soil quality indicators, these environmental indicators would be aligned with the provision of ecosystem services. The toolbox envisaged is a set of indicators for specific soil issues

The role of soil moisture on the coevolution of soil and vegetation in mountain grasslands

Science.gov (United States)

Bertoldi, Giacomo; Claudia, Notarnicola; Brenner, Johannes; Castelli, Mariapina; Greifeneder, Felix; Niedrist, Georg; Seeber, Julia; Tappeiner, Ulrike

2016-04-01

One of the key variables controlling the organization of vegetation and the coevolution of soils and landforms is soil moisture content (SMC). For this reason, understanding the controls on the spatial and temporal patterns of SMC is essential to predict how perturbations in vegetation and climate will affect mountain ecosystem functioning. In this contribution, we focus on the dynamic of surface SMC of water-limited alpine grasslands in the Long Term Ecological Research area Mazia Valley in the European Alps. We analyze the impacts of different land managements (meadows versus pastures) and its relationships with climate and topography. The area has been equipped since 2009 with a network of more than 20 stations, measuring SMC and climatic variables and with two eddy-covariance stations, measuring surface fluxes over meadows and pastures. Monthly biomass production data have been collected and detailed soil and spatial soil moisture surveys are available. Moreover, high spatial resolution SMC maps have been derived from satellites Synthetic Aperture Radar Radar (SAR) images (Sentinel 1 and RADARSAT2 images). Both ground surveys and remote sensing observations show persistent landscape-level patterns. Meadows, in general located in flatter areas, tend to be wetter. This leads to higher vegetation productivity and to the development of soils with higher water holding capacity, thus to a positive feedback on SMC. In contrast, pastures, located on steeper slopes with lower vegetation density and higher soil erosion, tend to be drier, leading to a negative feedback on SMC and soil development. This co-evolution of land cover and SMC leads therefore to persistent spatial patterns. In order to understand quantitatively such linked interactions, a sensitivity analysis has been performed with the GEOtop hydrological model. Results show how both abiotic (mainly slope and elevation) and anthropogenic (irrigation and soil management) factors exert a significant control on

The Soil Atlas of Africa: raising awareness and educate to the importance of soil

Science.gov (United States)

Dewitte, Olivier; Jones, Arwyn; Bosco, Claudio; Spaargaren, Otto; Montanarella, Luca

2010-05-01

available. These datasets will be useful for making broad distinction among soil types and provide general trends at the global and regional scales. The datasets will be made accessible for free downloading from the portals of the SOIL Action (http://eusoils.jrc.ec.europa.eu/) and the ACP Observatory for Sustainable Development (http://acpobservatory.jrc.ec.europa.eu). The Atlas links the theme of soil with rural development and, at the same time, supports the goals of the EU Thematic Strategy for Soil Protection in conserving a threatened natural resource that is vital to human existence. Not only climate change, but also desertification and loss of biodiversity are strongly affecting soils globally, making the "Soil Atlas of Africa" relevant to a much larger community of stakeholders involved in the implementation of the three "Rio-Conventions" and allowing to explore possible synergies among international multilateral agreements towards global soil protection.

Soil Science Society of America - K-12 Outreach

Science.gov (United States)

Lindbo, David L.; Loynachan, Tom; Mblia, Monday; Robinson, Clay; Chapman, Susan

2013-04-01

The Soil Science Society of America created its K12 Committee in 2006 in part to compliment the Dig It! The Secrets of Soil exhibit that opened in July 2008 at the Smithsonian's Institution's Nation Museum of Natural History (of which SSS was a founding sponsor). The committee's work began quickly with a website designed to provide resources for K12 teachers. The first accomplishments included reviewing and posting links to web based information already available to teachers. These links were sorted by subject and grade level to make it easier for teachers to navigate the web and find what they needed quickly. Several presentations and lessons designed for K12 teachers were also posted at this time. Concurrent with this effort a subcommittee review and organized the national teaching standards to show where soils could fit into the overall K12 curriculum. As the website was being developed another subcommittee developed a soils book (Soil! Get the Inside Scoop, 2008) to further compliment the Dig It! exhibit. This was a new endeavor for SSSA having never worked with the non-academic audience in developing a book. Peer-reviews of this book included not only scientist but also students in order to make sure the book was attractive to them. Once the book was published and the website developed it became clear more outreach was needed. SSSA K12 Committee has attended both the National Science Teachers Association (since 2008) the USA Science and Engineering Festival (since 2010) with exhibits and workshops. It has cooperated and contributed to the American Geologic Institutes' Earth Science Week materials with brochures and lesson plans and with National Association of Conservation Districts by providing peer-review and distribution of materials. The most recent developments from the committee include a web redesign that is more student and teacher friendly, the development of a peer-review system to publish K12 Lesson Plans, and finally the publication of a new soils

Local soil classification and crop suitability: Implications for the historical land use and soil management in Monti di Trapani (Sicily)

Science.gov (United States)

Garcia-Vila, Margarita; Corselli, Rocco; Bonet, María Teresa; Lopapa, Giuseppe; Pillitteri, Valentina; Fereres, Elias

2017-04-01

In the past, the lack of technologies (e.g. synthetic fertilizers) to overcome biophysical limitations has played a central role in land use planning. Thus, landscape management and agronomic practices are reactions to local knowledge and perceptions on natural resources, particularly soil. In the framework of the European research project MEMOLA (FP7), the role of local farmers knowledge and perceptions on soil for the historical land use through the spatial distribution of crops and the various management practices have been assessed in three different areas of Monti di Trapani region (Sicily). The identification of the soil classification systems of farmers and the criteria on which it is based, linked to the evaluation of the farmers' ability to identify and map the different soil types, was a key step. Nevertheless, beyond the comparison of the ethnopedological classification approach versus standard soil classification systems, the study also aims at understanding local soil management and land use decisions. The applied methodology was based on an interdisciplinary approach, combining soil science methods and participatory appraisal tools, particularly: i) semi-structured interviews; ii) soil sampling and analysis; iii) discussion groups; and iv) a workshop with local edafologists and agronomists. A rich local glossary of terms associated with the soil conditions and an own soil classification system have been identified in the region. Also, a detailed soil map, including process of soil degradation and soil capability, has been generated. This traditional soil knowledge has conditioned the management and the spatial distribution of the crops, and therefore the configuration of the landscape, until the 1990s. Acknowledgements This work has been funded by the European Union project MEMOLA (Grant agreement no: 613265).

Variation in pH optima of hydrolytic enzyme activities in tropical rain forest soils.

Science.gov (United States)

Turner, Benjamin L

2010-10-01

Extracellular enzymes synthesized by soil microbes play a central role in the biogeochemical cycling of nutrients in the environment. The pH optima of eight hydrolytic enzymes involved in the cycles of carbon, nitrogen, phosphorus, and sulfur, were assessed in a series of tropical forest soils of contrasting pH values from the Republic of Panama. Assays were conducted using 4-methylumbelliferone-linked fluorogenic substrates in modified universal buffer. Optimum pH values differed markedly among enzymes and soils. Enzymes were grouped into three classes based on their pH optima: (i) enzymes with acidic pH optima that were consistent among soils (cellobiohydrolase, β-xylanase, and arylsulfatase), (ii) enzymes with acidic pH optima that varied systematically with soil pH, with the most acidic pH optima in the most acidic soils (α-glucosidase, β-glucosidase, and N-acetyl-β-glucosaminidase), and (iii) enzymes with an optimum pH in either the acid range or the alkaline range depending on soil pH (phosphomonoesterase and phosphodiesterase). The optimum pH values of phosphomonoesterase were consistent among soils, being 4 to 5 for acid phosphomonoesterase and 10 to 11 for alkaline phosphomonoesterase. In contrast, the optimum pH for phosphodiesterase activity varied systematically with soil pH, with the most acidic pH optima (3.0) in the most acidic soils and the most alkaline pH optima (pH 10) in near-neutral soils. Arylsulfatase activity had a very acidic optimum pH in all soils (pH ≤3.0) irrespective of soil pH. The differences in pH optima may be linked to the origins of the enzymes and/or the degree of stabilization on solid surfaces. The results have important implications for the interpretation of hydrolytic enzyme assays using fluorogenic substrates.

Elevated tropospheric CO2 and O3 concentrations impair organic pollutant removal from grassland soil.

Science.gov (United States)

Ai, Fuxun; Eisenhauer, Nico; Jousset, Alexandre; Butenschoen, Olaf; Ji, Rong; Guo, Hongyan

2018-04-03

The concentrations of tropospheric CO 2 and O 3 have been rising due to human activities. These rising concentrations may have strong impacts on soil functions as changes in plant physiology may lead to altered plant-soil interactions. Here, the effects of eCO 2 and eO 3 on the removal of polycyclic aromatic hydrocarbon (PAH) pollutants in grassland soil were studied. Both elevated CO 2 and O 3 concentrations decreased PAH removal with lowest removal rates at elevated CO 2 and elevated O 3 concentrations. This effect was linked to a shift in soil microbial community structure by structural equation modeling. Elevated CO 2 and O 3 concentrations reduced the abundance of gram-positive bacteria, which were tightly linked to soil enzyme production and PAH degradation. Although plant diversity did not buffer CO 2 and O 3 effects, certain soil microbial communities and functions were affected by plant communities, indicating the potential for longer-term phytoremediation approaches. Results of this study show that elevated CO 2 and O 3 concentrations may compromise the ability of soils to degrade organic pollutants. On the other hand, the present study also indicates that the targeted assembly of plant communities may be a promising tool to shape soil microbial communities for the degradation of organic pollutants in a changing world.

Effects of irrigating poplar energy crops with landfill leachate on soil micro- and meso-fauna

Science.gov (United States)

Jill A. Zalesny; David R. Coyle; Ronald S. Jr. Zalesny; Adam H. Wiese

2009-01-01

Increased municipal solid waste generated worldwide combined with substantial demand for renewable energy has prompted testing and deployment of woody feedstock production systems that reuse and recycle wastewaters as irrigation and fertilization for the trees. Populus species and hybrids (i.e., poplars) are ideal for such systems given their fast...

Long-term Fertilization Structures Bacterial and Archaeal Communities along Soil Depth Gradient in a Paddy Soil

Directory of Open Access Journals (Sweden)

Yunfu Gu

2017-08-01

Full Text Available Soil microbes provide important ecosystem services. Though the effects of changes in nutrient availability due to fertilization on the soil microbial communities in the topsoil (tilled layer, 0–20 cm have been extensively explored, the effects on communities and their associations with soil nutrients in the subsoil (below 20 cm which is rarely impacted by tillage are still unclear. 16S rRNA gene amplicon sequencing was used to investigate bacterial and archaeal communities in a Pup-Calric-Entisol soil treated for 32 years with chemical fertilizer (CF and CF combined with farmyard manure (CFM, and to reveal links between soil properties and specific bacterial and archaeal taxa in both the top- and subsoil. The results showed that both CF and CFM treatments increased soil organic carbon (SOC, soil moisture (MO and total nitrogen (TN while decreased the nitrate_N content through the profile. Fertilizer applications also increased Olsen phosphorus (OP content in most soil layers. Microbial communities in the topsoil were significantly different from those in subsoil. Compared to the CF treatment, taxa such as Nitrososphaera, Nitrospira, and several members of Acidobacteria in topsoil and Subdivision 3 genera incertae sedis, Leptolinea, and Bellilinea in subsoil were substantially more abundant in CFM. A co-occurrence based network analysis demonstrated that SOC and OP were the most important soil parameters that positively correlated with specific bacterial and archaeal taxa in topsoil and subsoil, respectively. Hydrogenophaga was identified as the keystone genus in the topsoil, while genera Phenylobacterium and Steroidobacter were identified as the keystone taxa in subsoil. The taxa identified above are involved in the decomposition of complex organic compounds and soil carbon, nitrogen, and phosphorus transformations. This study revealed that the spatial variability of soil properties due to long-term fertilization strongly shapes the bacterial

The sensitivity of soil respiration to soil temperature, moisture, and carbon supply at the global scale.

Science.gov (United States)

Hursh, Andrew; Ballantyne, Ashley; Cooper, Leila; Maneta, Marco; Kimball, John; Watts, Jennifer

2017-05-01

Soil respiration (Rs) is a major pathway by which fixed carbon in the biosphere is returned to the atmosphere, yet there are limits to our ability to predict respiration rates using environmental drivers at the global scale. While temperature, moisture, carbon supply, and other site characteristics are known to regulate soil respiration rates at plot scales within certain biomes, quantitative frameworks for evaluating the relative importance of these factors across different biomes and at the global scale require tests of the relationships between field estimates and global climatic data. This study evaluates the factors driving Rs at the global scale by linking global datasets of soil moisture, soil temperature, primary productivity, and soil carbon estimates with observations of annual Rs from the Global Soil Respiration Database (SRDB). We find that calibrating models with parabolic soil moisture functions can improve predictive power over similar models with asymptotic functions of mean annual precipitation. Soil temperature is comparable with previously reported air temperature observations used in predicting Rs and is the dominant driver of Rs in global models; however, within certain biomes soil moisture and soil carbon emerge as dominant predictors of Rs. We identify regions where typical temperature-driven responses are further mediated by soil moisture, precipitation, and carbon supply and regions in which environmental controls on high Rs values are difficult to ascertain due to limited field data. Because soil moisture integrates temperature and precipitation dynamics, it can more directly constrain the heterotrophic component of Rs, but global-scale models tend to smooth its spatial heterogeneity by aggregating factors that increase moisture variability within and across biomes. We compare statistical and mechanistic models that provide independent estimates of global Rs ranging from 83 to 108 Pg yr -1 , but also highlight regions of uncertainty

Critical Zone Experimental Design to Assess Soil Processes and Function

Science.gov (United States)

Banwart, Steve

2010-05-01

Through unsustainable land use practices, mining, deforestation, urbanisation and degradation by industrial pollution, soil losses are now hypothesized to be much faster (100 times or more) than soil formation - with the consequence that soil has become a finite resource. The crucial challenge for the international research community is to understand the rates of processes that dictate soil mass stocks and their function within Earth's Critical Zone (CZ). The CZ is the environment where soils are formed, degrade and provide their essential ecosystem services. Key among these ecosystem services are food and fibre production, filtering, buffering and transformation of water, nutrients and contaminants, storage of carbon and maintaining biological habitat and genetic diversity. We have initiated a new research project to address the priority research areas identified in the European Union Soil Thematic Strategy and to contribute to the development of a global network of Critical Zone Observatories (CZO) committed to soil research. Our hypothesis is that the combined physical-chemical-biological structure of soil can be assessed from first-principles and the resulting soil functions can be quantified in process models that couple the formation and loss of soil stocks with descriptions of biodiversity and nutrient dynamics. The objectives of this research are to 1. Describe from 1st principles how soil structure influences processes and functions of soils, 2. Establish 4 European Critical Zone Observatories to link with established CZOs, 3. Develop a CZ Integrated Model of soil processes and function, 4. Create a GIS-based modelling framework to assess soil threats and mitigation at EU scale, 5. Quantify impacts of changing land use, climate and biodiversity on soil function and its value and 6. Form with international partners a global network of CZOs for soil research and deliver a programme of public outreach and research transfer on soil sustainability. The

Analysis of surface soil moisture patterns in agricultural landscapes using Empirical Orthogonal Functions

Directory of Open Access Journals (Sweden)

W. Korres

2010-05-01

Full Text Available Soil moisture is one of the fundamental variables in hydrology, meteorology and agriculture. Nevertheless, its spatio-temporal patterns in agriculturally used landscapes that are affected by multiple natural (rainfall, soil, topography etc. and agronomic (fertilisation, soil management etc. factors are often not well known. The aim of this study is to determine the dominant factors governing the spatio-temporal patterns of surface soil moisture in a grassland and an arable test site that are located within the Rur catchment in Western Germany. Surface soil moisture (0–6 cm was measured in an approx. 50×50 m grid during 14 and 17 measurement campaigns (May 2007 to November 2008 in both test sites. To analyse the spatio-temporal patterns of surface soil moisture, an Empirical Orthogonal Function (EOF analysis was applied and the results were correlated with parameters derived from topography, soil, vegetation and land management to link the patterns to related factors and processes. For the grassland test site, the analysis resulted in one significant spatial structure (first EOF, which explained 57.5% of the spatial variability connected to soil properties and topography. The statistical weight of the first spatial EOF is stronger on wet days. The highest temporal variability can be found in locations with a high percentage of soil organic carbon (SOC. For the arable test site, the analysis resulted in two significant spatial structures, the first EOF, which explained 38.4% of the spatial variability, and showed a highly significant correlation to soil properties, namely soil texture and soil stone content. The second EOF, which explained 28.3% of the spatial variability, is linked to differences in land management. The soil moisture in the arable test site varied more strongly during dry and wet periods at locations with low porosity. The method applied is capable of identifying the dominant parameters controlling spatio-temporal patterns of

Links between seawater flooding, soil ammonia oxidiser communities and their response to changes in salinity.

Science.gov (United States)

Nacke, Heiko; Schöning, Ingo; Schindler, Malte; Schrumpf, Marion; Daniel, Rolf; Nicol, Graeme W; Prosser, James I

2017-11-01

Coastal areas worldwide are challenged by climate change-associated increases in sea level and storm surge quantities that potentially lead to more frequent flooding of soil ecosystems. Currently, little is known of the effects of inundation events on microorganisms controlling nitrification in these ecosystems. The goal of this study was to investigate the impact of seawater flooding on the abundance, community composition and salinity tolerance of soil ammonia oxidisers. Topsoil was sampled from three islands flooded at different frequencies by the Wadden Sea. Archaeal ammonia oxidiser amoA genes were more abundant than their betaproteobacterial counterparts, and the distribution of archaeal and bacterial ammonia oxidiser amoA and 16S rRNA gene sequences significantly differed between the islands. The findings indicate selection of ammonia oxidiser phylotypes with greater tolerance to high salinity and slightly alkaline pH (e.g. Nitrosopumilus representatives) in frequently flooded soils. A cluster phylogenetically related to gammaproteobacterial ammonia oxidisers was detected in all samples analysed in this survey. Nevertheless, no gammaprotebacterial amoA genes could be amplified via PCR and only betaproteobacterial ammonia oxidisers were detected in enrichment cultures. A slurry-based experiment demonstrated the tolerance of both bacterial and archaeal ammonia oxidisers to a wide range of salinities (e.g. Wadden Sea water salinity) in soil naturally exposed to seawater at a high frequency. © FEMS 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Influence of mineral fertilization on edaphic fauna in Acacia auriculiformis (A. Cunn plantations

Directory of Open Access Journals (Sweden)

Liliana Parente Ribeiro

2014-02-01

Full Text Available Fertilization and/or the accumulation of organic matter from plant residues can influence the composition of soil and litter community. The goal of this study was to evaluate the effects of P and K fertilization on total faunal and nematode faunal composition and richness in plant litter and soil for 360 days in an area reforested with Acacia auriculiformis (A. Cunn, located in the municipality of Conceição de Macabu in the State of Rio de Janeiro. For each treatment (fertilized and unfertilized plots, samples of litter and soil (to a depth of 5 cm were collected and transferred into a Berlese-Tüllgren funnels for the extraction of fauna. Mesofauna and macrofauna were quantified, and the major taxa identified. Nematodes were extracted by centrifugal flotation in sucrose solution and identified according to feeding habits. Density (number of individuals m-2 of total fauna, microphages, social insects and saprophages varied significantly per treatment and sampling time in both litter and soil. The total number of individuals collected was 5,127, and the total number of nematodes 894. Phosphorus and potassium fertilization resulted in an increase in total fauna density and richness in the litter due to an increased abundance of social insects, saprophages and herbivores. In the soil, fertilization increased the saprophage and predator densities. Saprophages were the predominant taxa in the litter, while social insects (Formicidae prevailed in the soil. Litter nematode populations were favored by mineral fertilization. Bacteriophages were the predominant nematode group in both litter and soil.

Soil-Borne Microbial Functional Structure across Different Land Uses

NARCIS (Netherlands)

Kuramae, E.E.; Zhou, J.Z.; Kowalchuk, G.A.; van Veen, J.A..

2014-01-01

Land use change alters the structure and composition of microbial communities. However, the links between environmental factors and microbial functions are not well understood. Here we interrogated the functional structure of soil microbial communities across different land uses. In a multivariate

Soil-borne microbial functional structure across different land uses

NARCIS (Netherlands)

Kuramae, Eiko E; Zhou, Jizhong Z; Kowalchuk, George A; van Veen, Johannes A

2014-01-01

Land use change alters the structure and composition of microbial communities. However, the links between environmental factors and microbial functions are not well understood. Here we interrogated the functional structure of soil microbial communities across different land uses. In a multivariate

Linking temperature sensitivity of soil organic matter decomposition to its molecular structure, accessibility, and microbial physiology.

Science.gov (United States)

Wagai, Rota; Kishimoto-Mo, Ayaka W; Yonemura, Seiichiro; Shirato, Yasuhito; Hiradate, Syuntaro; Yagasaki, Yasumi

2013-04-01

Temperature sensitivity of soil organic matter (SOM) decomposition may have a significant impact on global warming. Enzyme-kinetic hypothesis suggests that decomposition of low-quality substrate (recalcitrant molecular structure) requires higher activation energy and thus has greater temperature sensitivity than that of high-quality, labile substrate. Supporting evidence, however, relies largely on indirect indices of substrate quality. Furthermore, the enzyme-substrate reactions that drive decomposition may be regulated by microbial physiology and/or constrained by protective effects of soil mineral matrix. We thus tested the kinetic hypothesis by directly assessing the carbon molecular structure of low-density fraction (LF) which represents readily accessible, mineral-free SOM pool. Using five mineral soil samples of contrasting SOM concentrations, we conducted 30-days incubations (15, 25, and 35 °C) to measure microbial respiration and quantified easily soluble C as well as microbial biomass C pools before and after the incubations. Carbon structure of LFs (soil was measured by solid-state (13) C-NMR. Decomposition Q10 was significantly correlated with the abundance of aromatic plus alkyl-C relative to O-alkyl-C groups in LFs but not in bulk soil fraction or with the indirect C quality indices based on microbial respiration or biomass. The warming did not significantly change the concentration of biomass C or the three types of soluble C despite two- to three-fold increase in respiration. Thus, enhanced microbial maintenance respiration (reduced C-use efficiency) especially in the soils rich in recalcitrant LF might lead to the apparent equilibrium between SOM solubilization and microbial C uptake. Our results showed physical fractionation coupled with direct assessment of molecular structure as an effective approach and supported the enzyme-kinetic interpretation of widely observed C quality-temperature relationship for short-term decomposition. Factors

Soil organic matter degradation and enzymatic profiles of intertidal and subaqueous soils

Science.gov (United States)

Ferronato, Chiara; Marinari, Sara; Bello, Diana; Vianello, Gilmo; Trasar-Cepeda, Carmen; Vittori Antisari, Livia

2017-04-01

of epipedons, reflect the influence of the type of annual biomass depositions on ITSs (i.e. Salicornia europaea), but also the important role of the tide oscillation that promotes the continuous alternation of red-ox exchanges and thus fasten the organic matter turnover in ITSs. On these pedons, invertase was the most effective enzymes (11.6 μmol glucose g-1h-1). Moreover, in SASs and ITSs, most of the activities linked to the degradation of exoskeletons and fungi (e.g. chitinase) increase along the soil profile, probably due to the disrupting effect of water on the soil and to the type of SOM in saltmarshes soils. By considering the specific activity (enzymatic activity/TOC content), data showed how SASs, ITSs and TESs had different oxidoreductases and hydrolases trends, suggesting a different path and effectiveness of SOM degradation, which probably depends both on the soil hydric regime, and on the different type of organic compounds. A particular increase of catalase and invertase specific activities along the soil profiles, suggests the presence of microaerophilic environment in some saturated AC and C sandy horizons but generally, it was observed a gradual decrease of biochemical alteration of the SOM by enzymatic activities along the soil profile due to the progressive restriction of the edaphic conditions.

Soils Newsletter, Vol. 38, No. 2, January 2016

International Nuclear Information System (INIS)

2016-02-01

In 2015 the Soil and Water Management and Crop Nutrition (SWMCN) Subprogramme held several events to celebrate the “International Year of Soils” (IYS), to raise awareness and improve the understanding on the importance of soil for food security and essential ecosystem functions. The side event on ‘Managing Soils for Climate-Smart Agriculture’ on 16 September 2015 during the 59th IAEA General Conference was well attended with more than 80 participants including many country delegations attending the IAEA General Conference. The four speakers from Member States showcased the successes and impacts in the field as well as their experience on the importance of soils in global food security, the impacts of climate change on soil and the crucial roles of nuclear applications for climate-smart agriculture. Similarly, the one-day conference on 7 December 2015 on “Celebration of the 2015 International Year of Soils: Achievements and Future Challenges”, with the International Union of Soil Science (IUSS), to coincide with World Soil Day on 5 December and to mark the closing of IYS. Speakers from all Regional Soil Science Societies reported on their achievements with regards to managing soils for sustainable crop production and intensification. Working groups discussed future challenges and opportunities for soil research and development, and international partnership and collaboration. The roles of isotopic and nuclear techniques for managing soils to combat land degradation, improve soil fertility and resource use efficiency, while reducing the environmental impacts of agriculture, and improving the nutritional quality of crops were highlighted during the conference. At the event, participants proclaimed the ‘Vienna Soil Declaration: Soil matters for humans and ecosystems’, which sets the framework for future research in soil science and links achievements to the United Nations’ Sustainable Development Goals and global endeavours to combat climate change

ENZYME-LINKED IMMUNOSORBENT ASSAY FOR SCREENING DIOXIN SOIL CONTAMINATION BY UNCONTROLLED COMBUSTION DURING INFORMAL RECYCLING IN SLUMS

Science.gov (United States)

Trindade, Mirta; Nording, Malin; Nichkova, Mikaela; Spinnel, Erik; Haglund, Peter; Last, Michael S.; Gee, Shirley; Hammock, Bruce; Last, Jerold A.; González-Sapienza, Gualberto; Brena, Beatriz M.

2010-01-01

Uncontrolled combustion due to garbage recycling is a widespread activity among slum dwellers in distressed economy countries and has been indicated as a major source of dioxin contamination. However, because of the high cost and complexity of gas chromatography/high-resolution mass spectrometry (GC-HRMS) analysis, the magnitude of the problem remains largely unknown. The present study describes a first approach toward the use of a dioxin antibody-based enzyme-linked immunosorbent assay (ELISA) as the basis for a sustainable, simple, and low-cost monitoring program to assess the toxicological impact of uncontrolled combustion in slums. A panel of 16 samples was analyzed by GC-HRMS and ELISA on split extracts. Close to 20% of the analyzed samples showed dioxin concentrations up to almost twice the guidance level for residential soil in several countries, pointing out the need for performing a large-scale monitoring program. Despite the potential for variations in dioxin congener distribution due to the mixed nature of the incinerated material, there was a good correlation between the toxic equivalents as determined by GC-HRMS and ELISA. Furthermore, an interlaboratory ELISA validation showed that the capacity to perform the dioxin ELISA was successfully transferred between laboratories. It was concluded that the ELISA method performed very well as a screening tool to prioritize samples for instrumental analysis, which allows cutting down costs significantly. PMID:18522475

Zinc fractionation in contaminated soils by sequential and single extractions: influence of soil properties and zinc content.

Science.gov (United States)

Voegelin, Andreas; Tokpa, Gerome; Jacquat, Olivier; Barmettler, Kurt; Kretzschmar, Ruben

2008-01-01

We studied the fractionation of zinc (Zn) in 49 contaminated soils as influenced by Zn content and soil properties using a seven-step sequential extraction procedure (F1: NH4NO3; F2: NH4-acetate, pH 6; F3: NH3OHCl, pH 6; F4: NH4-EDTA, pH 4.6; F5: NH4-oxalate, pH 3; F6: NH4-oxalate/ascorbic acid, pH 3; F7: residual). The soils had developed from different geologic materials and covered a wide range in soil pH (4.0-7.3), organic C content (9.3-102 g kg(-1)), and clay content (38-451 g kg(-1)). Input of aqueous Zn with runoff water from electricity towers during 26 to 74 yr resulted in total soil Zn contents of 3.8 to 460 mmol kg(-1). In acidic soils (n = 24; pH soils (n = 25; pH > or =6.0), most Zn was extracted in the mobilizable fraction (F2) and the intermediate fractions (F4 and F5). The extractability of Zn increased with increasing Zn contamination of the soils. The sum of mobile (F1) and mobilizable (F2) Zn was independent of soil pH, the ratio of Zn in F1 over F1+F2 plotted against soil pH, exhibited the typical shape of a pH sorption edge and markedly increased from pH 6 to pH 5, reflecting the increasing lability of mobilizable Zn with decreasing soil pH. In conclusion, the extractability of Zn from soils contaminated with aqueous Zn after decades of aging under field conditions systematically varied with soil pH and Zn content. The same trends are expected to apply to aqueous Zn released from decomposing Zn-bearing contaminants, such as sewage sludge or smelter slag. The systematic trends in Zn fractionation with varying soil pH and Zn content indicate the paramount effect of these two factors on molecular scale Zn speciation. Further research is required to characterize the link between the fractionation and speciation of Zn and to determine how Zn loading and soil physicochemical properties affect Zn speciation in soils.

Interrelationships between soil cover and plant cover depending on land use

Directory of Open Access Journals (Sweden)

Tiina Köster

2013-05-01

Full Text Available Interrelationships between soil cover and plant cover of normally developed (or postlithogenic mineral soils are analysed on the basis of four sampling soil groups. The four-link pedo-ecological sequence of analysed soils, rendzinas → brown soils → pseudopodzolic soils → gley-podzols, forms a representative cross section in relation to the normal mineral soils of Estonia. All groups differ substantially from each other in terms of soil properties (calcareousness, acidity, nutrition conditions, profile fabric and humus cover. The primary tasks of the research were (1 to elucidate the main pedo-ecological characteristics of the four soil groups and their suitability for plant cover, (2 to evaluate comparatively soils in terms of productivity, sustainability, biodiversity and environmental protection ability and (3 to analyse possibilities for ecologically sound matching of soil cover with suitable plant cover. On the basis of the same material, the influence of land-use change on humus cover (epipedon fabric, properties of the entire soil cover and soil–plant interrelationship were also analysed. An ecosystem approach enables us to observe particularities caused by specific properties of a soil type (species, variety in biological turnover and in the formation of biodiversity.

Uncertainty of Deardorff’s soil moisture model based on continuous TDR measurements for sandy loam soil

Directory of Open Access Journals (Sweden)

Brandyk Andrzej

2016-03-01

Full Text Available Knowledge on soil moisture is indispensable for a range of hydrological models, since it exerts a considerable influence on runoff conditions. Proper tools are nowadays applied in order to gain in-sight into soil moisture status, especially of uppermost soil layers, which are prone to weather changes and land use practices. In order to establish relationships between meteorological conditions and topsoil moisture, a simple model would be required, characterized by low computational effort, simple structure and low number of identified and calibrated parameters. We demonstrated, that existing model for shallow soils, considering mass exchange between two layers (the upper and the lower, as well as with the atmosphere and subsoil, worked well for sandy loam with deep ground water table in Warsaw conurbation. GLUE (Generalized Likelihood Uncertainty Estimation linked with GSA (Global Sensitivity Analysis provided for final determination of parameter values and model confidence ranges. Including the uncertainty in a model structure, caused that the median soil moisture solution of the GLUE was shifted from the one optimal in deterministic sense. From the point of view of practical model application, the main shortcoming were the underestimated water exchange rates between the lower soil layer (ranging from the depth of 0.1 to 0.2 m below ground level and subsoil. General model quality was found to be satisfactory and promising for its utilization for establishing measures to regain retention in urbanized conditions.

Soil Infrastructure, Interfaces & Translocation Processes in Inner Space ("Soil-it-is": towards a road map for the constraints and crossroads of soil architecture and biophysical processes

Directory of Open Access Journals (Sweden)

L. W. de Jonge

2009-08-01

Full Text Available Soil functions and their impact on health, economy, and the environment are evident at the macro scale but determined at the micro scale, based on interactions between soil micro-architecture and the transport and transformation processes occurring in the soil infrastructure comprising pore and particle networks and at their interfaces. Soil structure formation and its resilience to disturbance are highly dynamic features affected by management (energy input, moisture (matric potential, and solids composition and complexation (organic matter and clay interactions. In this paper we review and put into perspective preliminary results of the newly started research program "Soil-it-is" on functional soil architecture. To identify and quantify biophysical constraints on soil structure changes and resilience, we claim that new approaches are needed to better interpret processes and parameters measured at the bulk soil scale and their links to the seemingly chaotic soil inner space behavior at the micro scale. As a first step, we revisit the soil matrix (solids phase and pore system (water and air phases, constituting the complementary and interactive networks of soil infrastructure. For a field-pair with contrasting soil management, we suggest new ways of data analysis on measured soil-gas transport parameters at different moisture conditions to evaluate controls of soil matrix and pore network formation. Results imply that some soils form sponge-like pore networks (mostly healthy soils in terms of agricultural and environmental functions, while other soils form pipe-like structures (agriculturally poorly functioning soils, with the difference related to both complexation of organic matter and degradation of soil structure. The recently presented Dexter et al. (2008 threshold (ratio of clay to organic carbon of 10 kg kg⁻¹ is found to be a promising constraint for a soil's ability to maintain or regenerate functional structure. Next

Air-tough: A fully 3-dimensional linking of atmosphere with soil using eddy diffusivity concept and V-TOUGH

Energy Technology Data Exchange (ETDEWEB)

Montazer, P. [Multimedia Environmental Technology, Inc., Newport Beach, CA (United States)

1995-03-01

In arid climates, evapotranspiration is a strongly-coupled thermodynamic process that is controlled by the interaction of the atmospheric boundary layer and the upper soil surface. Simulation of this process requires a fully-coupled thermodynamic multi-phase fluid-flow and energy-transport code. Such a code was developed in a previous investigation using V-TOUGH. The resulting efficient computer code, A-TOUGH, simulates the effect of dynamic atmospheric fluctuations on vapor movement between the soil and the atmosphere and the resulting moisture movement in the soil. However, the coupling between the atmosphere and soil employed eddy diffusivity which was only a function of time and not a function of space. In the present study the code is extended to allow spatial as well as temporal variation of eddy diffusivity.

The history of soil erosion: Interpreting historical sources, buried soils and colluvial sediments as archives of past soil erosion and human-environment interactions in the Longue Durée

Science.gov (United States)

Dotterweich, Markus

2015-04-01

Soil erosion threatens the environment and the sustainability of agricultural practices since the earliest societies started modifying their natural environment in the Neolithic. Almost all farming-based cultures in the world, from large civilizations to peasant groups on little islands, have suffered from soil erosion by water. The amounts of soil erosion varied largely through time and space, and extreme events have left a wide variety of imprints on the landscape over millennia. Eroded hillslopes and gullies, deposited sediments in sinks like lakes, footslopes, valleys, floodplains, and river deltas are geomorphic legacies that have been linked to changes in land use and climate by many studies during the last decades. However, a standardized analysis and interpretation of these geomorphic legacies is problematic because of the variety of methodological approaches and the nonlinearity between soil erosion, climate, and land use. Cascading effects, land use structures, soil management, soil conservation strategies, and long-term system changes have produced different signals over time. Historical records are crucial and an invaluable source to provide alternative proxies about soil erosion in the past. Direct observations of individual soil erosion events may restrict the deposition of a distinct sediment package to a certain time span. They also expand the range of alternative interpretations, particularly with respect to the long-term effects of soil erosion to ecosystem services and socioeconomic processes. However, historical records also need critical analyses regarding their origin, intention, and quality. They were often created in the context of personal interests or political issues rather than being based on scientific facts; and it is often unclear if they represent certain events, narratives, or vague assumptions. This presentation will present and discuss examples of geomorphic evidences and historical records of past soil erosion for the deciphering

Improving Soil Seed Bank Management.

Science.gov (United States)

Haring, Steven C; Flessner, Michael L

2018-05-08

Problems associated with simplified weed management motivate efforts for diversification. Integrated weed management uses fundamentals of weed biology and applied ecology to provide a framework for diversified weed management programs; the soil seed bank comprises a necessary part of this framework. By targeting seeds, growers can inhibit the propagule pressure on which annual weeds depend for agricultural invasion. Some current management practices affect weed seed banks, such as crop rotation and tillage, but these tools are often used without specific intention to manage weed seeds. Difficulties quantifying the weed seed bank, understanding seed bank phenology, and linking seed banks to emerged weed communities challenge existing soil seed bank management practices. Improved seed bank quantification methods could include DNA profiling of the soil seed bank, mark and recapture, or 3D LIDAR mapping. Successful and sustainable soil seed bank management must constrain functionally diverse and changing weed communities. Harvest weed seed controls represent a step forward, but over-reliance on this singular technique could make it short-lived. Researchers must explore tools inspired by other pest management disciplines, such as gene drives or habitat modification for predatory organisms. Future weed seed bank management will combine multiple complementary practices that enhance diverse agroecosystems. This article is protected by copyright. All rights reserved.

Microbial responses to carbon and nitrogen supplementation in an Antarctic dry valley soil

DEFF Research Database (Denmark)

Dennis, P. G.; Sparrow, A. D.; Gregorich, E. G.

2013-01-01

The soils of the McMurdo Dry Valleys are exposed to extremely dry and cold conditions. Nevertheless, they contain active biological communities that contribute to the biogeochemical processes. We have used ester-linked fatty acid (ELFA) analysis to investigate the effects of additions of carbon...... and nitrogen in glucose and ammonium chloride, respectively, on the soil microbial community in a field experiment lasting three years in the Garwood Valley. In the control treatment, the total ELFA concentration was small by comparison with temperate soils, but very large when expressed relative to the soil...... organic carbon concentration, indicating efficient conversion of soil organic carbon into microbial biomass and rapid turnover of soil organic carbon. The ELFA concentrations increased significantly in response to carbon additions, indicating that carbon supply was the main constraint to microbial...

Links between plant and fungal communities across a deforestation chronosequence in the Amazon rainforest.

Science.gov (United States)

Mueller, Rebecca C; Paula, Fabiana S; Mirza, Babur S; Rodrigues, Jorge L M; Nüsslein, Klaus; Bohannan, Brendan J M

2014-07-01

Understanding the interactions among microbial communities, plant communities and soil properties following deforestation could provide insights into the long-term effects of land-use change on ecosystem functions, and may help identify approaches that promote the recovery of degraded sites. We combined high-throughput sequencing of fungal rDNA and molecular barcoding of plant roots to estimate fungal and plant community composition in soil sampled across a chronosequence of deforestation. We found significant effects of land-use change on fungal community composition, which was more closely correlated to plant community composition than to changes in soil properties or geographic distance, providing evidence for strong links between above- and below-ground communities in tropical forests.

Uncovering trophic positions and food resources of soil animals using bulk natural stable isotope composition.

Science.gov (United States)

Potapov, Anton M; Tiunov, Alexei V; Scheu, Stefan

2018-06-19

-vascular plants may play an important role in fuelling soil food webs. The trophic niche of most high-rank animal taxa spans at least two trophic levels, implying the use of a wide range of resources. Therefore, to identify trophic species and links in food webs, low-rank taxonomic identification is required. Despite overlap in feeding strategies, stable isotope composition of the high-rank taxonomic groups reflects differences in trophic level and in the use of basal resources. Different taxonomic groups of predators and decomposers are likely linked to different pools of organic matter in soil, suggesting different functional roles and indicating that trophic niches in soil animal communities are phylogenetically structured. During last two decades studies using stable isotope analysis have elucidated the trophic structure of soil communities, clarified basal food resources of the soil food web and revealed links between above- and belowground ecosystem compartments. Extending the use of stable isotope analysis to a wider range of soil-dwelling organisms, including microfauna, and a larger array of ecosystems provides the perspective of a comprehensive understanding of the structure and functioning of soil food webs. © 2018 Cambridge Philosophical Society.

Exploring functional relationships between post-fire soil water repellency, soil structure and physico-chemical properties

Science.gov (United States)

Quarfeld, Jamie; Brook, Anna; Keestra, Saskia; Wittenberg, Lea

2016-04-01

composition in determining wettability rather than quantity, as evidenced both by the high variation observed in the field and the strong presence of aliphatic functional groups in the absence of WR; and (ii) commonly proposed mechanisms affecting soil aggregate properties - albeit with differing temperature thresholds and longer exposure times employed in this study. Namely, these mechanisms tend to involve: (i) soil OM and WR reduction at low to moderate temperatures, and (ii) thermal fusion of particles within moderate to high temperatures. Overall, results suggest a positive influence of management on soil properties as well as high soil resilience to moderate severity fire disturbance in the studied areas. However, the specific changes in soil OM and mineral composition that are responsible for destruction of WR and subsequent changes in AS remain poorly understood. Based on these results, a key next step within this study will entail a closer examination of OC ratios and their potential links with certain mineral species known to influence soil aggregation and soil WR. Noting the importance of soil OM-mineralogical interactions on run-off and erosion processes, results may contribute to better prediction of post-fire responses in the future and improve the ability to fine-tune site specific management approaches accordingly.

Linking genes to ecosystem trace gas fluxes in a large-scale model system

Science.gov (United States)

Meredith, L. K.; Cueva, A.; Volkmann, T. H. M.; Sengupta, A.; Troch, P. A.

2017-12-01

Soil microorganisms mediate biogeochemical cycles through biosphere-atmosphere gas exchange with significant impact on atmospheric trace gas composition. Improving process-based understanding of these microbial populations and linking their genomic potential to the ecosystem-scale is a challenge, particularly in soil systems, which are heterogeneous in biodiversity, chemistry, and structure. In oligotrophic systems, such as the Landscape Evolution Observatory (LEO) at Biosphere 2, atmospheric trace gas scavenging may supply critical metabolic needs to microbial communities, thereby promoting tight linkages between microbial genomics and trace gas utilization. This large-scale model system of three initially homogenous and highly instrumented hillslopes facilitates high temporal resolution characterization of subsurface trace gas fluxes at hundreds of sampling points, making LEO an ideal location to study microbe-mediated trace gas fluxes from the gene to ecosystem scales. Specifically, we focus on the metabolism of ubiquitous atmospheric reduced trace gases hydrogen (H2), carbon monoxide (CO), and methane (CH4), which may have wide-reaching impacts on microbial community establishment, survival, and function. Additionally, microbial activity on LEO may facilitate weathering of the basalt matrix, which can be studied with trace gas measurements of carbonyl sulfide (COS/OCS) and carbon dioxide (O-isotopes in CO2), and presents an additional opportunity for gene to ecosystem study. This work will present initial measurements of this suite of trace gases to characterize soil microbial metabolic activity, as well as links between spatial and temporal variability of microbe-mediated trace gas fluxes in LEO and their relation to genomic-based characterization of microbial community structure (phylogenetic amplicons) and genetic potential (metagenomics). Results from the LEO model system will help build understanding of the importance of atmospheric inputs to

Final Progress Report on Model-Based Diagnosis of Soil Limitations to Forest Productivity

Energy Technology Data Exchange (ETDEWEB)

Luxmoore, R.J.

2004-08-30

This project was undertaken in support of the forest industry to link modeling of nutrients and productivity with field research to identify methods for enhancing soil quality and forest productivity and for alleviating soil limitations to sustainable forest productivity. The project consisted of a series of related tasks, including (1) simulation of changes in biomass and soil carbon with nitrogen fertilization, (2) development of spreadsheet modeling tools for soil nutrient availability and tree nutrient requirements, (3) additional modeling studies, and (4) evaluation of factors involved in the establishment and productivity of southern pine plantations in seasonally wet soils. This report also describes the two Web sites that were developed from the research to assist forest managers with nutrient management of Douglas-fir and loblolly pine plantations.

Mechanistic modelling of the vertical soil organic matter profile

NARCIS (Netherlands)

Braakhekke, M.C.

2014-01-01

Soil organic matter (SOM) constitutes a large global pool of carbon that may play a considerable role for future climate. The vertical distribution of SOM in the profile may be important due to depth-dependence of physical, chemical, and biological conditions, and links to physical processes

Magnetic Properties of Different-Aged Chernozemic Soils

Science.gov (United States)

Fattakhova, Leysan; Shinkarev, Alexandr; Kosareva, Lina; Nourgaliev, Danis; Shinkarev, Aleksey; Kondrashina, Yuliya

2016-04-01

We investigated the magnetic properties and degree of mineral weathering in profiles of different-aged chernozemic soils derived from a uniform parent material. In this work, layer samples of virgin leached chernozem and chernozemic soils formed on the mound of archaeological earthy monument were used. The characterization of the magnetic properties was carried out on the data of the magnetometry and differential thermomagnetic analysis. The evaluation of the weathering degree was carried out on a loss on ignition, cation exchange capacity and X-ray phase analysis on the data of the original soil samples and samples of the heavy fraction of minerals. It was found that the magnetic susceptibility enhancement in humus profiles of newly formed chernozemic soils lagged significantly behind the organic matter content enhancement. This phenomenon is associated with differences in kinetic parameters of humus formation and structural and compositional transformation of the parent material. It is not enough time of 800-900 years to form a relatively "mature" magnetic profile. These findings are well consistent with the chemical kinetic model (Boyle et al., 2010) linking the formation of the soils magnetic susceptibility with the weathering of primary Fe silicate minerals. Different-aged chernozemic soils are at the first stage of formation of a magnetic profile when it is occur an active production of secondary ferrimagnetic minerals from Fe2+ released by primary minerals.

Factors affecting the selection of a soil water sensing technology

International Nuclear Information System (INIS)

Hignett, C.T.

2000-01-01

Reviews of soil moisture measurement technologies are counterproductive in attempting to identify the single approach that has the best overall performance for a range of soil, crop and landscape conditions. Not only does such an approach preclude the addition of new technologies, but it also obscures the fact that we have available today sensors and technologies that cover most field conditions, are well understood in terms of technical capability and are mechanically and electronically reliable. This review defines decision-making processes for assessing the characteristics, good and bad, of technology in relation to project objectives. Two processes are needed. The first links soil texture and scale of variability with the nature of the project, single-plant to catchment scale, to the needs for soil water measurement. The second lists the capabilities of some devices and shows how they can be selected to accommodate necessary criteria. It is concluded that the 'best technology' is a function of the project and soil conditions. (author)

Seasonal GPR Signal Changes in Two Contrasting Soils in the Shale Hills Catchment

Science.gov (United States)

Lin, H.; Zhang, J.; Doolittle, J. A.

2011-12-01

Repeated GPR surveys in different seasons, combined with real-time soil water monitoring, provide a useful methodology to reveal subsurface hydrologic processes and their underlying mechanisms in different soils and hillslopes. This was demonstrated in the Shale Hills Critical Zone Observatory using two contrasting soils over several dry and wet seasons. Our results showed that 1) the radar reflection in the BC-C horizon interface in the deep Rushtown soil became clearer as soil became wetter, which was linked to lateral flow above this horizon interface that increased the contrast, and 2) the reflection in the soil-bedrock interface and the weathered-unweathered rock interface in the shallow Weikert soil become intermittent as soil became wetter, which was attributed to non-uniform distribution of water in bedrock fractures that created locally strong contrast, leading to point scatter of GPR reflection. This study shows the optimal time for using GPR to detect soil horizon interfaces, the value of nondestructive mapping of soil-rock moisture distribution patterns, and the possibility of identifying preferential flow pathways in the subsurface.

Microbial interactions with organic contaminants in soil: Definitions, processes and measurement

International Nuclear Information System (INIS)

Semple, Kirk T.; Doick, Kieron J.; Wick, Lukas Y.; Harms, Hauke

2007-01-01

There has been and continues to be considerable scientific interest in predicting bioremediation rates and endpoints. This requires the development of chemical techniques capable of reliably predicting the bioavailability of organic compounds to catabolically active soil microbes. A major issue in understanding the link between chemical extraction and bioavailability is the problem of definition; there are numerous definitions, of varying degrees of complexity and relevance, to the interaction between organic contaminants and microorganisms in soil. The aim of this review is to consider the bioavailability as a descriptor for the rate and extent of biodegradation and, in an applied sense, bioremediation of organic contaminants in soil. To address this, the review will (i) consider and clarify the numerous definitions of bioavailability and discuss the usefulness of the term 'bioaccessibility'; (ii) relate definition to the microbiological and chemical measurement of organic contaminants' bioavailability in soil, and (iii) explore the mechanisms employed by soil microorganisms to attack organic contaminants in soil. - Understanding organic contaminant's behaviour in soil is key to chemically predicting biodegradation

Evidence of soil radon as tracer of magma uprising in Mt. Etna

International Nuclear Information System (INIS)

Morelli, D.; Martino, S. Di; Imme, G.; La Delfa, S.; Lo Nigro, S.; Patane, G.

2006-01-01

Soil radon has been monitored at one fixed site located in the northeastern flank of Mt. Etna, high-risk volcano in Sicily. The aim of this study was the evaluation of a possible link between magma uprising and soil radon concentration. Continuous radon measurements were performed since July 2001. Comparison between the in-soil radon trend and the acquired meteorological series (Temperature, Humidity and Pressure) seems to confirm a general seasonal correlation; nevertheless some anomalies suggest a possible dependence of the radon concentration on volcanic dynamics, as confirmed by the volcanic tremor and strain-release analysis

A novel soil manganese mechanism drives plant species loss with increased nitrogen deposition in a temperate steppe.

Science.gov (United States)

Tian, Qiuying; Liu, Nana; Bai, Wenming; Li, Linghao; Chen, Jiquan; Reich, Peter B; Yu, Qiang; Guo, Dali; Smith, Melinda D; Knapp, Alan K; Cheng, Weixin; Lu, Peng; Gao, Yan; Yang, An; Wang, Tianzuo; Li, Xin; Wang, Zhengwen; Ma, Yibing; Han, Xingguo; Zhang, Wen-Hao

2016-01-01

Loss of plant diversity with increased anthropogenic nitrogen (N) deposition in grasslands has occurred globally. In most cases, competitive exclusion driven by preemption of light or space is invoked as a key mechanism. Here, we provide evidence from a 9-yr N-addition experiment for an alternative mechanism: differential sensitivity of forbs and grasses to increased soil manganese (Mn) levels. In Inner Mongolia steppes, increasing the N supply shifted plant community composition from grass-forb codominance (primarily Stipa krylovii and Artemisia frigida, respectively) to exclusive dominance by grass, with associated declines in overall species richness. Reduced abundance of forbs was linked to soil acidification that increased mobilization of soil Mn, with a 10-fold greater accumulation of Mn in forbs than in grasses. The enhanced accumulation of Mn in forbs was correlated with reduced photosynthetic rates and growth, and is consistent with the loss of forb species. Differential accumulation of Mn between forbs and grasses can be linked to fundamental differences between dicots and monocots in the biochemical pathways regulating metal transport. These findings provide a mechanistic explanation for N-induced species loss in temperate grasslands by linking metal mobilization in soil to differential metal acquisition and impacts on key functional groups in these ecosystems.

Improving soil enzyme activities and related quality properties of reclaimed soil by applying weathered coal in opencast-mining areas of the Chinese loess plateau

Energy Technology Data Exchange (ETDEWEB)

Li, Hua [College of Environment and Resources, Shanxi University, Taiyuan (China); CAS/Shandong Provincial Key Laboratory of Coastal Environmental Process, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences (CAS), Yantai (China); Shao, Hongbo [CAS/Shandong Provincial Key Laboratory of Coastal Environmental Process, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences (CAS), Yantai (China); Institute for Life Sciences, Qingdao University of Science and Technology (QUST), Qingdao (China); Li, Weixiang; Bi, Rutian [Shanxi Agricultural University, Taigu (China); Bai, Zhongke [Department of Land Science Technology, University of Geosciences, Beijing (China)

2012-03-15

There are many problems for the reclaimed soil in opencast-mining areas of the Loess Plateau of China such as poor soil structure and extreme poverty in soil nutrients and so on. For the sake of finding a better way to improve soil quality, the current study was to apply the weathered coal for repairing soil media and investigate the physicochemical properties of the reclaimed soil and the changes in enzyme activities after planting Robinia pseucdoacacia. The results showed that the application of the weathered coal significantly improved the quality of soil aggregates, increased the content of water stable aggregates, and the organic matter, humus, and the cation exchange capacity of topsoil were significantly improved, but it did not have a significant effect on soil pH. Planting R. pseucdoacacia significantly enhanced the activities of soil catalase, urease, and invertase, but the application of the weathered coal inhibited the activity of catalase. Although the application of appropriate weathered coal was able to significantly increase urease activity, the activities of catalase, urease, or invertase had a close link with the soil profile levels and time. This study suggests that applying weathered coals could improve the physicochemical properties and soil enzyme activities of the reclaimed soil in opencast-mining areas of the Loess Plateau of China and the optimum applied amount of the weathered coal for reclaimed soil remediation is about 27 000 kg hm{sup -2}. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Interactive biotic and abiotic regulators of soil carbon cycling: evidence from controlled climate experiments on peatland and boreal soils.

Science.gov (United States)

Briones, María Jesús I; McNamara, Niall P; Poskitt, Jan; Crow, Susan E; Ostle, Nicholas J

2014-09-01

Partially decomposed plant and animal remains have been accumulating in organic soils (i.e. >40% C content) for millennia, making them the largest terrestrial carbon store. There is growing concern that, in a warming world, soil biotic processing will accelerate and release greenhouse gases that further exacerbate climate change. However, the magnitude of this response remains uncertain as the constraints are abiotic, biotic and interactive. Here, we examined the influence of resource quality and biological activity on the temperature sensitivity of soil respiration under different soil moisture regimes. Organic soils were sampled from 13 boreal and peatland ecosystems located in the United Kingdom, Ireland, Spain, Finland and Sweden, representing a natural resource quality range of C, N and P. They were incubated at four temperatures (4, 10, 15 and 20 °C) at either 60% or 100% water holding capacity (WHC). Our results showed that chemical and biological properties play an important role in determining soil respiration responses to temperature and moisture changes. High soil C : P and C : N ratios were symptomatic of slow C turnover and long-term C accumulation. In boreal soils, low bacterial to fungal ratios were related to greater temperature sensitivity of respiration, which was amplified in drier conditions. This contrasted with peatland soils which were dominated by bacterial communities and enchytraeid grazing, resulting in a more rapid C turnover under warmer and wetter conditions. The unexpected acceleration of C mineralization under high moisture contents was possibly linked to the primarily role of fermented organic matter, instead of oxygen, in mediating microbial decomposition. We conclude that to improve C model simulations of soil respiration, a better resolution of the interactions occurring between climate, resource quality and the decomposer community will be required. © 2014 John Wiley & Sons Ltd.

Link Between the Seismic Events and the Different Seismic Precursor Phenomena

Directory of Open Access Journals (Sweden)

Mirela GHEORGHITA

2009-12-01

Full Text Available This article presents an analysis of the earthquake prediction methods, highlighting mainly the VLF and LF electromagnetic waves seismic precursors’ monitoring method and the correlation among these in order to obtain a more precise result. It is well known the fact that there are lots of links between the seismic events occurrence and different phenomena that predict their occurrence, such as theelectromagnetic field, Earth movement, gaseous content of radon and hydrogen within the soil, or within the underground waters. This paper aims to demonstrate the close link between the seismic events and the electromagnetic wave propagation anomalies, which are recorded before the advent of an earthquake.

Soil infiltration based on bp neural network and grey relational analysis

Directory of Open Access Journals (Sweden)

Wang Juan

2013-02-01

Full Text Available Soil infiltration is a key link of the natural water cycle process. Studies on soil permeability are conducive for water resources assessment and estimation, runoff regulation and management, soil erosion modeling, nonpoint and point source pollution of farmland, among other aspects. The unequal influence of rainfall duration, rainfall intensity, antecedent soil moisture, vegetation cover, vegetation type, and slope gradient on soil cumulative infiltration was studied under simulated rainfall and different underlying surfaces. We established a six factor-model of soil cumulative infiltration by the improved back propagation (BP-based artificial neural network algorithm with a momentum term and self-adjusting learning rate. Compared to the multiple nonlinear regression method, the stability and accuracy of the improved BP algorithm was better. Based on the improved BP model, the sensitive index of these six factors on soil cumulative infiltration was investigated. Secondly, the grey relational analysis method was used to individually study grey correlations among these six factors and soil cumulative infiltration. The results of the two methods were very similar. Rainfall duration was the most influential factor, followed by vegetation cover, vegetation type, rainfall intensity and antecedent soil moisture. The effect of slope gradient on soil cumulative infiltration was not significant.

GEMAS - Soil geochemistry and health implications

Science.gov (United States)

Ernstsen, Vibeke; Ladenberger, Anna; Wragg, Joanna; Gulan, Aleksandra

2014-05-01

The GEMAS Project resulted in a large coherent data set displaying baseline levels of elements in agricultural and grazing land soil, which has a wide variety of applications. Medical geology is an emerging new discipline providing a link between geoscience and medicine by interpreting natural geological factors in relation to human and animal health and their geographical distribution. Medical geology shows not only problems related to harmful health effects of natural geological materials and processes, but also deals with their beneficial aspects. Since the GEMAS project demonstrates the importance of geological factors in geochemical patterns in European soil, this data set can be used in improving our understanding of how the geological processes may affect human health in Europe. The main potential health problems are related to deficiency of nutrients in soil and toxic effects of potentially harmful elements. Deficiency in macro- (e.g., K, Fe, Mg, P) and micro-nutrients (e.g., Se, Zn, Cl) can be responsible for a reduction in crop productivity and certain health issues for livestock and humans. On the other hand, bioavailability of crucial elements depends on soil parameters, e.g., pH; namely, low pH in soil (in northern Europe) makes more micronutrients bioavailable, with the exception of Mo, P and Ca. Rocks underlying the soil layer have a major impact on soil composition, and soil parent material can be a main source of toxic metals, for instance, soil developed on black shale (e.g., Oslo region) shows potentially toxic levels of metals, such as As, Cd, U, Zn and Pb. High content of organic matter is another factor amplifying the toxic levels of metals in soil. Several important topics with health implications can be then addressed using the GEMAS data set, namely, soil properties and element bioavailability, arsenic toxicity, selenium deficiency, potential health effects of liming, uranium in European soil, influence of recent and historical volcanic

Influence of soil γ-irradiation and spiking on sorption of p,p'-DDE and soil organic matter chemistry.

Science.gov (United States)

Škulcová, Lucia; Scherr, Kerstin E; Chrást, Lukáš; Hofman, Jakub; Bielská, Lucie

2018-07-15

The fate of organic chemicals and their metabolites in soils is often investigated in model matrices having undergone various pre-treatment steps that may qualitatively or quantitatively interfere with the results. Presently, effects associated with soil sterilization by γ-irradiation and soil spiking using an organic solvent were studied in one freshly spiked soil (sterilization prior to contamination) and its field-contaminated (sterilization after contamination) counterpart for the model organic compound 1,1-Dichloro-2,2-bis(4-chlorophenyl)ethene (p,p'-DDE). Changes in the sorption and potential bioavailability of spiked and native p,p'-DDE were measured by supercritical fluid extraction (SFE), XAD-assisted extraction (XAD), and solid-phase microextraction (SPME) and linked to qualitative changes in soil organic matter (SOM) chemistry measured by diffuse reflectance infrared Fourier-transform (DRIFT) spectroscopy. Reduced sorption of p,p´-DDE detected with XAD and SPME was associated more clearly with spiking than with sterilization, but SFE showed a negligible impact. Spiking resulted in an increase of the DRIFT-derived hydrophobicity index, but irradiation did not. Spectral peak height ratio descriptors indicated increasing hydrophobicity and hydrophilicity in pristine soil following sterilization, and a greater reduction of hydrophobic over hydrophilic groups as a consequence of spiking. In parallel, reduced sorption of p,p´-DDE upon spiking was observed. Based on the present samples, γ-irradiation appears to alter soil sorptive properties to a lesser extent when compared to common laboratory processes such as spiking with organic solvents. Copyright © 2018. Published by Elsevier Inc.

Cadmium and lead occurrence in soil and grape from Murfatlar Vineyard

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Matei Nicoleta

2015-06-01

Full Text Available The study investigates the pollution with heavy metals of grapes and soil. The grapes nourish from the respective soil, with all existing substances: either nutrients or toxic materials. This link, between grapes and soil, made mandatory to focus on observing the level of toxic materials in both samples grapes and land. The aim of this research is to analyze the level of Cd and Pb in Vitis vinifera L. grape fruits and soil, by flame atomic absorption spectrometry (FAAS method. The grapes and the soil used in this work were sampled from the Murfatlar City, a nonindustrial area, placed far from the car traffic pollution. Cd and Pb were quantified, after the chemical mineralization of the samples using nitric acid. It can be noticed that the values of cadmium and lead concentrations in grapes were lower than the recommendable maximum limit.

The EU Dimension to Soil Science in Schools

Science.gov (United States)

Johnson, Sue

2012-01-01

The EU as a context for science lessons may be given scant attention but EU decision-making is a vital factor in everyday life. Lessons on the emergence of soil science with Charles Darwin's simple scientific experiments can be linked with competence through action, inclusion and argumentations in science lessons. Decisions about an EU Soil…

Automated Soil Physical Parameter Assessment Using Smartphone and Digital Camera Imagery

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Matt Aitkenhead

2016-12-01

Full Text Available Here we present work on using different types of soil profile imagery (topsoil profiles captured with a smartphone camera and full-profile images captured with a conventional digital camera to estimate the structure, texture and drainage of the soil. The method is adapted from earlier work on developing smartphone apps for estimating topsoil organic matter content in Scotland and uses an existing visual soil structure assessment approach. Colour and image texture information was extracted from the imagery. This information was linked, using geolocation information derived from the smartphone GPS system or from field notes, with existing collections of topography, land cover, soil and climate data for Scotland. A neural network model was developed that was capable of estimating soil structure (on a five-point scale, soil texture (sand, silt, clay, bulk density, pH and drainage category using this information. The model is sufficiently accurate to provide estimates of these parameters from soils in the field. We discuss potential improvements to the approach and plans to integrate the model into a set of smartphone apps for estimating health and fertility indicators for Scottish soils.

Soil factors effects on life history attributes of Leiothrix spiralis and Leiothrix vivipara (Eriocaulaceae) on rupestrian grasslands in Southeastern Brazil.

Science.gov (United States)

Coelho, F F; Martins, R P; Figueira, J E C; Demetrio, G R

2014-11-01

In this study, we hypothesized that the life history traits of Leiothrix spiralis and L. vivipara would be linked to soil factors of the rupestrian grasslands and that rosette size would be influenced by soil moisture. Soil analyses were performed from five populations of L. spiralis and four populations of L. vivipara. In each area, three replicates were employed in 19 areas of occurrence of Leiothrix species, and we quantified the life history attributes. The microhabitats of these species show low favorability regarding to soil factors. During the dry season, their rosettes decreased in diameter due the loss of its most outlying leaves. The absence of seedlings indicated the low fecundity of both species. However, both species showed rapid population growth by pseudovivipary. Both L. spiralis and L. vivipara exhibit a kind of parental care that was quantified by the presence of connections between parental-rosettes and ramets. The findings of the present study show that the life history traits are linked to soil factors.

Soil fertility management: Impacts on soil macrofauna, soil aggregation and soil organic matter allocation.

NARCIS (Netherlands)

Ayuke, F.O.; Brussaard, L.; Vanlauwe, B.; Six, J.; Lelei, D.K.; Kibunja, C.N.; Pulleman, M.M.

2011-01-01

Maintenance of soil organic matter through integrated soil fertility management is important for soil quality and agricultural productivity, and for the persistence of soil faunal diversity and biomass. Little is known about the interactive effects of soil fertility management and soil macrofauna

An integrated study to analyze soil microbial community structure and metabolic potential in two forest types.

Science.gov (United States)

Zhang, Yuguang; Cong, Jing; Lu, Hui; Yang, Caiyun; Yang, Yunfeng; Zhou, Jizhong; Li, Diqiang

2014-01-01

Soil microbial metabolic potential and ecosystem function have received little attention owing to difficulties in methodology. In this study, we selected natural mature forest and natural secondary forest and analyzed the soil microbial community and metabolic potential combing the high-throughput sequencing and GeoChip technologies. Phylogenetic analysis based on 16S rRNA sequencing showed that one known archaeal phylum and 15 known bacterial phyla as well as unclassified phylotypes were presented in these forest soils, and Acidobacteria, Protecobacteria, and Actinobacteria were three of most abundant phyla. The detected microbial functional gene groups were related to different biogeochemical processes, including carbon degradation, carbon fixation, methane metabolism, nitrogen cycling, phosphorus utilization, sulfur cycling, etc. The Shannon index for detected functional gene probes was significantly higher (PThe regression analysis showed that a strong positive (Pthe soil microbial functional gene diversity and phylogenetic diversity. Mantel test showed that soil oxidizable organic carbon, soil total nitrogen and cellulose, glucanase, and amylase activities were significantly linked (Pthe relative abundance of corresponded functional gene groups. Variance partitioning analysis showed that a total of 81.58% of the variation in community structure was explained by soil chemical factors, soil temperature, and plant diversity. Therefore, the positive link of soil microbial structure and composition to functional activity related to ecosystem functioning was existed, and the natural secondary forest soil may occur the high microbial metabolic potential. Although the results can't directly reflect the actual microbial populations and functional activities, this study provides insight into the potential activity of the microbial community and associated feedback responses of the terrestrial ecosystem to environmental changes.

Indicadores de qualidade do solo em sistemas de cultivo orgânico e convencional no semi-árido cearense Soil quality indicators in organic and conventional cultivation systems in the semi arid areas of Ceara - Brazil

Directory of Open Access Journals (Sweden)

Herdjania Veras de Lima

2007-10-01

samples collected in the layers 0-10, 10-20 and 20-30 cm. Physical, chemical and biological (macro and mesofauna soil properties were evaluated and analyzed by univariate and multivariate statistical techniques. Individually, the physical and chemical parameters were not sensitive enough to differentiate organic from conventional production systems. The multivariate analyses (Principal components and Anderson discriminant obtained satisfactory results, distinguishing organic from conventional management areas and from those in transition. Areas cultivated under organic systems were distinguished satisfactorily and most precisely from areas under conventional systems based on difference in soil fauna

Soil manganese enrichment from industrial inputs: a gastropod perspective.

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Despina-Maria Bordean

Full Text Available Manganese is one of the most abundant metal in natural environments and serves as an essential microelement for all living systems. However, the enrichment of soil with manganese resulting from industrial inputs may threaten terrestrial ecosystems. Several studies have demonstrated harmful effects of manganese exposure by cutaneous contact and/or by soil ingestion to a wide range of soil invertebrates. The link between soil manganese and land snails has never been made although these invertebrates routinely come in contact with the upper soil horizons through cutaneous contact, egg-laying, and feeding activities in soil. Therefore, we have investigated the direct transfer of manganese from soils to snails and assessed its toxicity at background concentrations in the soil. Juvenile Cantareus aspersus snails were caged under semi-field conditions and exposed first, for a period of 30 days, to a series of soil manganese concentrations, and then, for a second period of 30 days, to soils with higher manganese concentrations. Manganese levels were measured in the snail hepatopancreas, foot, and shell. The snail survival and shell growth were used to assess the lethal and sublethal effects of manganese exposure. The transfer of manganese from soil to snails occurred independently of food ingestion, but had no consistent effect on either the snail survival or shell growth. The hepatopancreas was the best biomarker of manganese exposure, whereas the shell did not serve as a long-term sink for this metal. The kinetics of manganese retention in the hepatopancreas of snails previously exposed to manganese-spiked soils was significantly influenced by a new exposure event. The results of this study reveal the importance of land snails for manganese cycling in terrestrial biotopes and suggest that the direct transfer from soils to snails should be considered when precisely assessing the impact of anthropogenic Mn releases on soil ecosystems.

Elastic and plastic soil deformation and its influence on emission of greenhouse gases

Science.gov (United States)

Haas, Christoph; Holthusen, Dörthe; Mordhorst, Anneka; Lipiec, Jerzy; Horn, Rainer

2016-04-01

Soil management alters physical, chemical and biological soil properties. Stress application affects microbiological activity and habitats for microorganisms in the root zone and causes soil degradation. We hypothesized that stress application results in altered greenhouse gas emissions if soil strength is exceeded. In the experiments, soil management dependent greenhouse gas emissions of intact soil cores (no, reduced, conventional tillages) were determined using two experimental setups; CO2 emissions were determined with: a dynamic measurement system, and a static chamber method before and after a vertical soil stress had been applied. For the latter CH4 and N2O emissions were analyzed additionally. Stress dependent effects can be summed as follows: In the elastic deformation range microbiological activity increased in conventional tillage soil and decreased in reduced tillage and no tillage. Beyond the precompression stress a release of formerly protected soil organic carbon and an almost total loss of CH4 oxidizability occurred. Only swelling and shrinkage of no tillage and reduced tillage regenerated their microhabitat function. Thus, the direct link between soil strength and microbial activity can be applied as a marker for soil rigidity and the transition to new disequilibria concerning microbial activity and composition.

Effect of the soil type on the microbiome in the rhizosphere of field-grown lettuce

OpenAIRE

Schreiter, Susanne; Ding, Guo-Chun; Heuer, Holger; Neumann, Günter; Sandmann, Martin; Grosch, Rita; Kropf, Siegfried; Smalla, Kornelia

2014-01-01

The complex and enormous diversity of microorganisms associated with plant roots is important for plant health and growth and is shaped by numerous factors. This study aimed to unravel the effects of the soil type on bacterial communities in the rhizosphere of field-grown lettuce. We used an experimental plot system with three different soil types that were stored at the same site for 10 years under the same agricultural management to reveal differences directly linked to the soil type and no...

Effect of the soil type on the microbiome in the rhizosphere of field-grown lettuce

OpenAIRE

Susanne eSchreiter; Susanne eSchreiter; Guo-chun eDing; Guo-chun eDing; Holger eHeuer; Günter eNeumann; Martin eSandmann; Rita eGrosch; Siegfried eKropf; Kornelia eSmalla

2014-01-01

The complex and enormous diversity of microorganisms associated with plant roots is important for plant health and growth and is shaped by numerous factors. This study aimed to unravel the effects of the soil type on bacterial communities in the rhizosphere of field-grown lettuce. We used an experimental plot system with three different soil types that were stored at the same site for ten years under the same agricultural management to reveal differences directly linked to the soil type and n...

Introducing BASE: the Biomes of Australian Soil Environments soil microbial diversity database.

Science.gov (United States)

Bissett, Andrew; Fitzgerald, Anna; Meintjes, Thys; Mele, Pauline M; Reith, Frank; Dennis, Paul G; Breed, Martin F; Brown, Belinda; Brown, Mark V; Brugger, Joel; Byrne, Margaret; Caddy-Retalic, Stefan; Carmody, Bernie; Coates, David J; Correa, Carolina; Ferrari, Belinda C; Gupta, Vadakattu V S R; Hamonts, Kelly; Haslem, Asha; Hugenholtz, Philip; Karan, Mirko; Koval, Jason; Lowe, Andrew J; Macdonald, Stuart; McGrath, Leanne; Martin, David; Morgan, Matt; North, Kristin I; Paungfoo-Lonhienne, Chanyarat; Pendall, Elise; Phillips, Lori; Pirzl, Rebecca; Powell, Jeff R; Ragan, Mark A; Schmidt, Susanne; Seymour, Nicole; Snape, Ian; Stephen, John R; Stevens, Matthew; Tinning, Matt; Williams, Kristen; Yeoh, Yun Kit; Zammit, Carla M; Young, Andrew

2016-01-01

Microbial inhabitants of soils are important to ecosystem and planetary functions, yet there are large gaps in our knowledge of their diversity and ecology. The 'Biomes of Australian Soil Environments' (BASE) project has generated a database of microbial diversity with associated metadata across extensive environmental gradients at continental scale. As the characterisation of microbes rapidly expands, the BASE database provides an evolving platform for interrogating and integrating microbial diversity and function. BASE currently provides amplicon sequences and associated contextual data for over 900 sites encompassing all Australian states and territories, a wide variety of bioregions, vegetation and land-use types. Amplicons target bacteria, archaea and general and fungal-specific eukaryotes. The growing database will soon include metagenomics data. Data are provided in both raw sequence (FASTQ) and analysed OTU table formats and are accessed via the project's data portal, which provides a user-friendly search tool to quickly identify samples of interest. Processed data can be visually interrogated and intersected with other Australian diversity and environmental data using tools developed by the 'Atlas of Living Australia'. Developed within an open data framework, the BASE project is the first Australian soil microbial diversity database. The database will grow and link to other global efforts to explore microbial, plant, animal, and marine biodiversity. Its design and open access nature ensures that BASE will evolve as a valuable tool for documenting an often overlooked component of biodiversity and the many microbe-driven processes that are essential to sustain soil function and ecosystem services.

Moleculo Long-Read Sequencing Facilitates Assembly and Genomic Binning from Complex Soil Metagenomes

Energy Technology Data Exchange (ETDEWEB)

White, Richard Allen; Bottos, Eric M.; Roy Chowdhury, Taniya; Zucker, Jeremy D.; Brislawn, Colin J.; Nicora, Carrie D.; Fansler, Sarah J.; Glaesemann, Kurt R.; Glass, Kevin; Jansson, Janet K.; Langille, Morgan

2016-06-28

functional roles in ecosystem stability and responses to environmental perturbations. This knowledge gap is largely due to the difficulty in culturing the majority of soil microbes. Thus, use of culture-independent approaches, such as metagenomics, promises the direct assessment of the functional potential of soil microbiomes. Soil is, however, a challenge for metagenomic assembly due to its high microbial diversity and variable evenness, resulting in low coverage and uneven sampling of microbial genomes. Despite increasingly large soil metagenome data volumes (>200 Gbp), the majority of the data do not assemble. Here, we used the cutting-edge approach of synthetic long-read sequencing technology (Moleculo) to assemble soil metagenome sequence data into long contigs and used the assemblies for binning of genomes.

Author Video: Anlink ext-link-type='uri' href='https://www.youtube.com/watch?v=J3KamOrdg1Q'>author video summarylink>of this article is available.

Climate Change, Soils, and Human Health

Science.gov (United States)

Brevik, Eric C.

2013-04-01

According to the Intergovernmental Panel on Climate Change, global temperatures are expected to increase 1.1 to 6.4 degrees C during the 21st century and precipitation patterns will be altered by climate change (IPCC, 2007). Soils are intricately linked to the atmospheric/climate system through the carbon, nitrogen, and hydrologic cycles. Altered climate will, therefore, have an effect on soil processes and properties. Studies into the effects of climate change on soil processes and properties are still incomplete, but have revealed that climate change will impact soil organic matter dynamics including soil organisms and the multiple soil properties that are tied to organic matter, soil water, and soil erosion. The exact direction and magnitude of those impacts will be dependent on the amount of change in atmospheric gases, temperature, and precipitation amounts and patterns. Recent studies give reason to believe at least some soils may become net sources of atmospheric carbon as temperatures rise; this is particularly true of high latitude regions with permanently frozen soils. Soil erosion by both wind and water is also likely to increase. These soil changes will lead to both direct and indirect impacts on human health. Possible indirect impacts include temperature extremes, food safety and air quality issues, increased and/or expanded disease incidences, and occupational health issues. Potential direct impacts include decreased food security and increased atmospheric dust levels. However, there are still many things we need to know more about. How climate change will affect the nitrogen cycle and, in turn, how the nitrogen cycle will affect carbon sequestration in soils is a major research need, as is a better understanding of soil water-CO2 level-temperature relationships. Knowledge of the response of plants to elevated atmospheric CO2 given limitations in nutrients like nitrogen and phosphorus and how that affects soil organic matter dynamics is a critical

Soil nitrate reducing processes - drivers, mechanisms for spatial variation, and significance for nitrous oxide production.

Science.gov (United States)

Giles, Madeline; Morley, Nicholas; Baggs, Elizabeth M; Daniell, Tim J

2012-01-01

The microbial processes of denitrification and dissimilatory nitrate reduction to ammonium (DNRA) are two important nitrate reducing mechanisms in soil, which are responsible for the loss of nitrate ([Formula: see text]) and production of the potent greenhouse gas, nitrous oxide (N(2)O). A number of factors are known to control these processes, including O(2) concentrations and moisture content, N, C, pH, and the size and community structure of nitrate reducing organisms responsible for the processes. There is an increasing understanding associated with many of these controls on flux through the nitrogen cycle in soil systems. However, there remains uncertainty about how the nitrate reducing communities are linked to environmental variables and the flux of products from these processes. The high spatial variability of environmental controls and microbial communities across small sub centimeter areas of soil may prove to be critical in determining why an understanding of the links between biotic and abiotic controls has proved elusive. This spatial effect is often overlooked as a driver of nitrate reducing processes. An increased knowledge of the effects of spatial heterogeneity in soil on nitrate reduction processes will be fundamental in understanding the drivers, location, and potential for N(2)O production from soils.

The self-reinforcing feedback between low soil fertility and chronic poverty

Science.gov (United States)

Barrett, Christopher B.; Bevis, Leah E. M.

2015-12-01

Most of the world's extreme poor, surviving on US$1.25 or less per day, live in rural areas and farm for a living. Many suffer chronic poverty that lasts for years or generations, rather than the transitory poverty that dominates developed, urban economies. Such chronic, structural poverty arises when an individual's productive assets -- such as their ability to work or their soils -- and the technologies and markets that transform their assets into food and income are insufficient to attain satisfactory living standards. Research reveals strong links between economic status and soil quality, and these can be self-reinforcing. For example, poor soil constrains agricultural production and household capital, and low household capital constrains investments in improving soils. Price, availability and access to credit can limit farmers' applications of nutrients, which are often the primary constraint on agricultural productivity. Soil micronutrient deficiencies can lead to dietary mineral deficiencies and negative health outcomes that further constrain productivity and household asset accumulation. Soils may also be important for smallholder resilience to stressors and shocks. For example, high-quality soil can reduce vulnerability to drought, and insurance against risk may promote investment in soils. Interventions such as fertilizer subsidies, micronutrient-fortified fertilizer and improved access to information, insurance and credit may all help break the soil-poverty cycle.

The tillage effect on the soil acid and alkaline phosphatase activity

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Lacramioara Oprica

2011-12-01

Full Text Available Phosphatases (acid and alkaline are important in soils because these extracellular enzymes catalyze the hydrolysis of organic phosphate esters to orthophosphate; thus they form an important link between biologically unavailable and mineral phosphorous. Phosphatase activity is sensitive to environmental perturbations such as organic amendments, tillage, waterlogging, compaction, fertilizer additions and thus it is often used as an environmental indicator of soil quality in riparian ecosystems. The aim of the study was to assess the effect of tillage systems on phosphatases activity in a field experiment carried out in Ezăreni farm. The phosphatase activitiy were determined at two depths (7-10 cm and 15-25cm layers of a chernozem soil submitted to conventional tillage (CT in a fertilised and unfertilised experiment. Monitoring soil alkaline phosphatase activity showed, generally, the same in fertilized soil profiles collected from both depths; the values being extremely close. In unfertilized soils, alkaline phosphatase activity is different only in soils that were exposed to unconventional work using disc harrows and 30cm tillage. Both works type (no tillage and conventional tillage cause an intense alkaline phosphatase activity in 7-10 cm soil profile. Acid phosphatase activity is highly fluctuating in both fertilized as well unfertilized soil, this enzyme being influenced by the performed works.

Prediction of soil properties for agricultural and environmental applications from infrared and X-ray soil spectral properties

International Nuclear Information System (INIS)

Towett, Erick Kibet

2013-01-01

tested for inferring soil chemical and physical functional properties which is of interest in the African soil context for agricultural and environmental management at large scale. Further, this thesis has helped to improve understanding of the variation and patterns of element concentration data for 1034 soil samples from 34 stratified randomly-located 100-km 2 ''sentinel'' sites across SSA and explored the link between variability of soil properties and climate, parent material, vegetation types and land use patterns with the help of Random Forests statistics. MIR showed remarkable ability to capture total elemental composition effects on physico-chemical soil properties but TXRF may have potential for outlier detection in large studies. This study has also helped to develop high-throughput spectral analytical methods and provided recommendations on optimal spectral analytical methods for the Globally Integrated Africa Soil Information Service (AfSIS) Project. Successfully developed methods in this study will become part of the standard AfSIS procedures.

Prediction of soil properties for agricultural and environmental applications from infrared and X-ray soil spectral properties

Energy Technology Data Exchange (ETDEWEB)

Towett, Erick Kibet

2013-12-09

tested for inferring soil chemical and physical functional properties which is of interest in the African soil context for agricultural and environmental management at large scale. Further, this thesis has helped to improve understanding of the variation and patterns of element concentration data for 1034 soil samples from 34 stratified randomly-located 100-km{sup 2} ''sentinel'' sites across SSA and explored the link between variability of soil properties and climate, parent material, vegetation types and land use patterns with the help of Random Forests statistics. MIR showed remarkable ability to capture total elemental composition effects on physico-chemical soil properties but TXRF may have potential for outlier detection in large studies. This study has also helped to develop high-throughput spectral analytical methods and provided recommendations on optimal spectral analytical methods for the Globally Integrated Africa Soil Information Service (AfSIS) Project. Successfully developed methods in this study will become part of the standard AfSIS procedures.

Environmental concentration and atmospheric deposition of halogenated flame retardants in soil from Nepal: Source apportionment and soil-air partitioning.

Science.gov (United States)

Yadav, Ishwar Chandra; Devi, Ningombam Linthoingambi; Li, Jun; Zhang, Gan

2018-02-01

While various investigations have been driven on polybrominated diphenyl ethers (PBDEs) and other flame retardants (FRs) in different framework around the world, information about contamination and fate of PBDEs and other FRs in developing countries especially in the Indian subcontinent is uncommon. Nepal being located in the Indian subcontinent, very little is known about contamination level of semi-volatile organic pollutants discharged into the environment. This motivated us to investigate the environmental fate of halogenated flame retardant (HFRs) in Nepalese condition. In this study, we investigated the concentration, fate, and sources of 9 PBDEs, 2 dechlorane plus isomers (DPs), and 6 novel brominated flame retardants (NBFRs). Moreover, air-soil exchange and soil-air partitioning were also evaluated to characterize the pattern of air-soil exchange and environmental fate. In general, the concentrations of NBFRs in soil were more prevalent than PBDEs and DPs, and accounted 95% of ∑HFRs. By and large, the concentrations of NBFRs and DPs were measured high in Kathmandu, while PBDEs level exceeded in Pokhara. Principal component analysis (PCA) study suggested contributions from commercial penta-, octa-, and deca-BDEs products and de-bromination of highly brominated PBDEs as the significant source of PBDEs. Likewise, low f anti ratio suggested DPs in soil might have originated from long-range atmospheric transport from remote areas, while high levels of decabromodiphenyl ethane (DBDPE) in soil were linked with the use of wide varieties of consumer products. The estimated fugacity fraction (ff) for individual HFR was quite lower (soil is overwhelming. Soil-air partitioning study revealed neither octanol-air partition coefficient (K OA ) nor black carbon partition coefficient (K BC-A ) is an appropriate surrogate for soil organic matter (SOM), subsequently, absorption by SOM has no or little role in the partitioning of HFRs. Copyright © 2017 Elsevier Ltd. All

Linking the distribution of carbon isotope ratios in soil carbonates and speleothems to climate conditions in the past: A model for the dependence of respiration rate on soil moisture

Science.gov (United States)

Liu, Y.; Ibarra, D. E.; Winnick, M.; Caves Rugenstein, J. K.; Oster, J. L.; Druhan, J. L.

2017-12-01

The carbon isotope compositions (δ13C) of atmospheric CO2, C3-origin organic carbon, and limestone epikarst differ substantially, resulting in variable δ13C signatures recorded in secondary soil carbonates and speleothems which represent a mixture of these sources. Even though this signal has been widely used in paleoclimate studies, the extent to which carbonate δ13C is influenced by the dynamic response of organic carbon respiration rates to soil moisture variations has yet to be fully evaluated [1]. Soils that are rewetted after a prolonged drought commonly display a peak in respiration rate followed by relaxation to a lower steady state in both lab incubation experiments and field observations. This transient behavior, known as the Birch effect, has been extensively observed across a broad range of locations and soil types, and may generate more than 50% of the total respired CO2 in some ecosystems [2]. Here, we seek to identify the influence of the Birch effect on carbonate δ13C records based on a moisture-dependent modeling approach. We report compiled respiration rates of soils from the literature and fit these data as a function of soil moisture, before imposing exponential dampening with depth and applying the resulting function in a production-diffusion equation [3]. We then implement a mass balance calculation for the δ13C value of carbonate precipitated from a mixture of atmospheric and respired CO2, including mass-dependent fractionation associated with diffusive transport. Our results offer a novel prediction for depth-resolved carbonate δ13C as a function of soil moisture, and suggest that Birch effect signals may be recorded in soil carbonates and influence the magnitude of carbonate δ13C variations in speleothems. Thus, we illustrate a prediction for the range of carbonate δ13C recorded in terrestrial carbonates and suggest that differences in the range of carbonate δ13C may indicate changes in soil moisture variability, providing a new

Some Remarks on Practical Aspects of Laboratory Testing of Deep Soil Mixing Composites Achieved in Organic Soils

Science.gov (United States)

Kanty, Piotr; Rybak, Jarosław; Stefaniuk, Damian

2017-10-01

This paper presents the results of laboratory testing of organic soil-cement samples are presented in the paper. The research program continues previously reported the authors’ experiences with cement-fly ash-soil sample testing. Over 100 of compression and a dozen of tension tests have been carried out altogether. Several samples were waiting for failure test for over one year after they were formed. Several factors, like: the large amount of the tested samples, a long observation time, carrying out the tests in complex cycles of loading and the possibility of registering the loads and deformation in the axial and lateral direction - have made it possible to take into consideration numerous interdependencies, three of which have been presented in this work: the increments of compression strength, the stiffness of soil-cement in relation to strength and the tensile strength. Compressive strength, elastic modulus and tensile resistance of cubic samples were examined. Samples were mixed and stored in the laboratory conditions. Further numerical analysis in the Finite Element Method numerical code Z_Soil, were performed on the basis of laboratory test results. Computations prove that cement-based stabilization of organic soil brings serious risks (in terms of material capacity and stiffness) and Deep Soil Mixing technology should not be recommended for achieving it. The numerical analysis presented in the study below includes only one type of organic and sandy soil and several possible geometric combinations. Despite that, it clearly points to the fact that designing the DSM columns in the organic soil may be linked with a considerable risk and the settlement may reach too high values. During in situ mixing, the organic material surrounded by sand layers surely mixes with one another in certain areas. However, it has not been examined and it is difficult to assume such mixing already at the designing stage. In case of designing the DSM columns which goes through a

Making US Soil Taxonomy more scientifically applicable to environmental and food security issues.

Science.gov (United States)

Monger, Curtis; Lindbo, David L.; Wysocki, Doug; Schoeneberger, Phil; Libohova, Zamir

2017-04-01

US Department of Agriculture began mapping soils in the 1890s on a county-by-county basis until most of the conterminous United States was mapped by the late 1930s. This first-generation mapping was followed by a second-generation that re-mapped the US beginning in the 1940s. Soil classification during these periods evolved into the current system of Soil Taxonomy which is based on (1) soil features as natural phenomena and on (2) soil properties important for agriculture and other land uses. While this system has enabled communication among soil surveyors, the scientific applicability of Soil Taxonomy to address environmental and food security issues has been under-utilized. In particular, little effort has been exerted to understand how soil taxa interact and function together as larger units—as soil systems. Thus, much soil-geomorphic understanding that could be applied to process-based modeling remains unexploited. The challenge for soil taxonomists in the United States and elsewhere is to expand their expertise and work with modelers to explore how soil taxa are linked to each other, how they influence water, nutrient, and pollutant flow through the landscape, how they interact with ecology, and how they change with human land use.

Relationship between sugarcane rust severity and soil properties in louisiana.

Science.gov (United States)

Johnson, Richard M; Grisham, Michael P; Richard, Edward P

2007-06-01

ABSTRACT The extent of spatial and temporal variability of sugarcane rust (Puccinia melanocephala) infestation was related to variation in soil properties in five commercial fields of sugarcane (interspecific hybrids of Saccharum spp., cv. LCP 85-384) in southern Louisiana. Sugarcane fields were grid-soil sampled at several intensities and rust ratings were collected at each point over 6 to 7 weeks. Soil properties exhibited significant variability (coefficients of variation = 9 to 70.1%) and were spatially correlated in 39 of 40 cases with a range of spatial correlation varying from 39 to 201 m. Rust ratings were spatially correlated in 32 of 33 cases, with a range varying from 29 to 241 m. Rust ratings were correlated with several soil properties, most notably soil phosphorus (r = 0.40 to 0.81) and soil sulfur (r = 0.36 to 0.68). Multiple linear regression analysis resulted in coefficients of determination that ranged from 0.22 to 0.73, and discriminant analysis further improved the overall predictive ability of rust models. Finally, contour plots of soil properties and rust levels clearly suggested a link between these two parameters. These combined data suggest that sugarcane growers that apply fertilizer in excess of plant requirements will increase the incidence and severity of rust infestations in their fields.

Endogeic earthworms shape bacterial functional communities and affect organic matter mineralization in a tropical soil

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Bernard, Laetitia; Chapuis-Lardy, Lydie; Razafimbelo, Tantely; Razafindrakoto, Malalatiana; Pablo, Anne-Laure; Legname, Elvire; Poulain, Julie; Brüls, Thomas; O'Donohue, Michael; Brauman, Alain; Chotte, Jean-Luc; Blanchart, Eric

2012-01-01

Priming effect (PE) is defined as a stimulation of the mineralization of soil organic matter (SOM) following a supply of fresh organic matter. This process can have important consequences on the fate of SOM and on the management of residues in agricultural soils, especially in tropical regions where soil fertility is essentially based on the management of organic matter. Earthworms are ecosystem engineers known to affect the dynamics of SOM. Endogeic earthworms ingest large amounts of soil and assimilate a part of organic matter it contains. During gut transit, microorganisms are transported to new substrates and their activity is stimulated by (i) the production of readily assimilable organic matter (mucus) and (ii) the possible presence of fresh organic residues in the ingested soil. The objective of our study was to see (i) whether earthworms impact the PE intensity when a fresh residue is added to a tropical soil and (ii) whether this impact is linked to a stimulation/inhibition of bacterial taxa, and which taxa are affected. A tropical soil from Madagascar was incubated in the laboratory, with a 13C wheat straw residue, in the presence or absence of a peregrine endogeic tropical earthworm, Pontoscolex corethrurus. Emissions of 12CO2 and 13CO2 were followed during 16 days. The coupling between DNA-SIP (stable isotope probing) and pyrosequencing showed that stimulation of both the mineralization of wheat residues and the PE can be linked to the stimulation of several groups especially belonging to the Bacteroidetes phylum. PMID:21753801

Establishing an International Soil Modelling Consortium

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Vereecken, Harry; Schnepf, Andrea; Vanderborght, Jan

2015-04-01

-change-feedback processes, bridge basic soil science research and management, and facilitate the communication between science and society . To meet these challenges an international community effort is required, similar to initiatives in systems biology, hydrology, and climate and crop research. We therefore propose to establish an international soil modelling consortium with the aims of 1) bringing together leading experts in modelling soil processes within all major soil disciplines, 2) addressing major scientific gaps in describing key processes and their long term impacts with respect to the different functions and ecosystem services provided by soil, 3) intercomparing soil model performance based on standardized and harmonized data sets, 4) identifying interactions with other relevant platforms related to common data formats, protocols and ontologies, 5) developing new approaches to inverse modelling, calibration, and validation of soil models, 6) integrating soil modelling expertise and state of the art knowledge on soil processes in climate, land surface, ecological, crop and contaminant models, and 7) linking process models with new observation, measurement and data evaluation technologies for mapping and characterizing soil properties across scales. Our consortium will bring together modelers and experimental soil scientists at the forefront of new technologies and approaches to characterize soils. By addressing these aims, the consortium will contribute to improve the role of soil modeling as a knowledge dissemination instrument in addressing key global issues and stimulate the development of translational research activities. This presentation will provide a compelling case for this much-needed effort, with a focus on tangible benefits to the scientific and food security communities.

Quantitative laws governing the migration of magnesium, calcium, radium-226, thorium-228 in the link between soils and plants

International Nuclear Information System (INIS)

Ashkinazi, E.I.

1982-02-01

Concentrations of magnesium, calcium, radium 226 and thorium 228 in podsolized chernozem and medium-loamy soils and in agricultural plants (wheat, barley, peas, potatoes, beets, and carrots) were determined. Transition coefficients of magnesium, calcium and radium 226 from soils to plants were calculated

Extension of the Hapke bidirectional reflectance model to retrieve soil water content

Directory of Open Access Journals (Sweden)

G.-J. Yang

2011-07-01

Full Text Available Soil moisture links the hydrologic cycle and the energy budget of land surfaces by regulating latent heat fluxes. An accurate assessment of the spatial and temporal variation of soil moisture is important to the study of surface biogeophysical processes. Although remote sensing has proven to be one of the most powerful tools for obtaining land surface parameters, no effective methodology yet exists for in situ soil moisture measurement based on a Bidirectional Reflectance Distribution Function (BRDF model, such as the Hapke model. To retrieve and analyze soil moisture, this study applied the soil water parametric (SWAP-Hapke model, which introduced the equivalent water thickness of soil, to ground multi-angular and hyperspectral observations coupled with, Powell-Ant Colony Algorithm methods. The inverted soil moisture data resulting from our method coincided with in situ measurements (R² = 0.867, RMSE = 0.813 based on three selected bands (672 nm, 866 nm, 2209 nm. It proved that the extended Hapke model can be used to estimate soil moisture with high accuracy based on the field multi-angle and multispectral remote sensing data.

An increase in precipitation exacerbates negative effects of nitrogen deposition on soil cations and soil microbial communities in a temperate forest.

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Shi, Leilei; Zhang, Hongzhi; Liu, Tao; Mao, Peng; Zhang, Weixin; Shao, Yuanhu; Fu, Shenglei

2018-04-01

World soils are subjected to a number of anthropogenic global change factors. Although many previous studies contributed to understand how single global change factors affect soil properties, there have been few studies aimed at understanding how two naturally co-occurring global change drivers, nitrogen (N) deposition and increased precipitation, affect critical soil properties. In addition, most atmospheric N deposition and precipitation increase studies have been simulated by directly adding N solution or water to the forest floor, and thus largely neglect some key canopy processes in natural conditions. These previous studies, therefore, may not realistically simulate natural atmospheric N deposition and precipitation increase in forest ecosystems. In a field experiment, we used novel canopy applications to investigate the effects of N deposition, increased precipitation, and their combination on soil chemical properties and the microbial community in a temperate deciduous forest. We found that both soil chemistry and microorganisms were sensitive to these global change factors, especially when they were simultaneously applied. These effects were evident within 2 years of treatment initiation. Canopy N deposition immediately accelerated soil acidification, base cation depletion, and toxic metal accumulation. Although increased precipitation only promoted base cation leaching, this exacerbated the effects of N deposition. Increased precipitation decreased soil fungal biomass, possible due to wetting/re-drying stress or to the depletion of Na. When N deposition and increased precipitation occurred together, soil gram-negative bacteria decreased significantly, and the community structure of soil bacteria was altered. The reduction of gram-negative bacterial biomass was closely linked to the accumulation of the toxic metals Al and Fe. These results suggested that short-term responses in soil cations following N deposition and increased precipitation could change

The role of soil weathering and hydrology in regulating chemical fluxes from catchments (Invited)

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Maher, K.; Chamberlain, C. P.

2010-12-01

Catchment-scale chemical fluxes have been linked to a number of different parameters that describe the conditions at the Earth’s surface, including runoff, temperature, rock type, vegetation, and the rate of tectonic uplift. However, many of the relationships relating chemical denudation to surface processes and conditions, while based on established theoretical principles, are largely empirical and derived solely from modern observations. Thus, an enhanced mechanistic basis for linking global solute fluxes to both surface processes and climate may improve our confidence in extrapolating modern solute fluxes to past and future conditions. One approach is to link observations from detailed soil-based studies with catchment-scale properties. For example, a number of recent studies of chemical weathering at the soil-profile scale have reinforced the importance of hydrologic processes in controlling chemical weathering rates. An analysis of data from granitic soils shows that weathering rates decrease with increasing fluid residence times and decreasing flow rates—over moderate fluid residence times, from 5 days to 10 years, transport-controlled weathering explains the orders of magnitude variation in weathering rates to a better extent than soil age. However, the importance of transport-controlled weathering is difficult to discern at the catchment scale because of the range of flow rates and fluid residence times captured by a single discharge or solute flux measurement. To assess the importance of transport-controlled weathering on catchment scale chemical fluxes, we present a model that links the chemical flux to the extent of reaction between the soil waters and the solids, or the fluid residence time. Different approaches for describing the distribution of fluid residence times within a catchment are then compared with the observed Si fluxes for a limited number of catchments. This model predicts high solute fluxes in regions with high run-off, relief, and

Soil Assessment along Toposequences in Rural Northern Nigeria: A Geomedical Approach

Directory of Open Access Journals (Sweden)

Lena Hartmann

2014-01-01

Full Text Available Case numbers of endemic Ca-deficiency rickets (CDR have been reported to be alarmingly rising among children of subsistence farms in developing countries within the last 30 years. Fluoride toxicities in the environment are known to not be related to the disease. To investigate if, instead, CDR is caused by a nutrient deficiency in the environment, subsistence farms in an endemic CDR area near Kaduna, northern Nigeria, were investigated for bedrock, slope forms, soil types, and soil characteristics. The natural environment was investigated according to the World Reference Base, soil texture was analysed by pipette and sieving, and plant-available macronutrients were determined using barium-chloride or Ca-acetate-lactate extraction. The analyses showed that granite and slope deposits were the dominant parent materials. The typical slope forms and soil types were Lixisols and Acrisols on pediments, Fluvisols in river valleys, and Plinthosols and Acrisols on plains. Compared with West African background values, all of the soils had normal soil textures but were low in macronutrients. Comparisons to critical limits, however, showed that only the P concentrations were critically low, which are typical for savanna soils. A link between nutrient deficiency in soils and CDR in the Kaduna area was therefore considered unlikely.

Relationship Between Physical Properties and Magnetism of Soils From Various Pedoenvironments

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Jordanova, N.; Jordanova, D.; Todorova, D.; Hirt, A.; Petrov, P.

2009-05-01

Characterization of soils with respect to their fertility, sustainable use and conservation require extensive, time- consuming and costly analyses. Establishment of well defined relationships between certain physical, geochemical and magnetic parameters would be useful tool in pedometrics, giving opportunity to carry out large scale studies on soil properties in more economically effective and fast way. Interdisciplinary analysis of 15 type soils from different pedoenvironments (oxidative, water-logged, salty, etc.) includes extensive magnetic measurements (magnetic susceptibility, anhysteretic (ARM) and isothermal (IRM) remanences, hysteresis parameters); determination of a set of physical characteristics (grain size fractions, pH) and geochemical analyses (total Fe content, oxalate- and dithionite-soluble Fe). Empirical linear relationship is found between soil reaction (pH) and magnetic susceptibility for aerobic soils, and negative relationship between pH and ARM for water-logged soils. Different type soils, showing magnetic enhancement along the solum, show higher ARM intensity with increasing percent of the clay fraction. This feature most probably is related to the fact that pedogenic ferrimagnetic minerals are strongly linked to clay fraction. The absence of such correlation for soils, affected by water-logging conditions suggests prevailing role of amorphous phases and antiferromagnetic Fe oxides in magnetic mineralogy. The role of pedogenic factors for particular behavior of other magnetic parameters will be discussed.

Variation in soil aluminium tolerance genes is associated with local adaptation to soils at the Park Grass Experiment.

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Gould, Billie; McCouch, Susan; Geber, Monica

2014-12-01

Studies of the wild grass Anthoxanthum odoratum at the long-term Park Grass Experiment (PGE, Harpenden, UK) document a well-known example of rapid plant evolution in response to environmental change. Repeated fertilizer applications have acidified the soil in some experimental plots over the past 150+ years, and Anthoxanthum subpopulations have quickly become locally adapted. Early reciprocal transplants showed subpopulation differentiation specifically in response to soil aluminium (Al) toxicity across the experiment, even at small (30 m) spatial scales. Almost 40 years after its original measurement, we reassessed the degree of local adaptation to soil Al at the PGE using updated phenotyping methods and identified genes with variation linked to the tolerance trait. Root growth assays show that plants are locally adapted to soil Al at both the seedling and adult growth stages, but to a smaller extent than previously inferred. Among a large suite of candidate loci that were previously shown to have Al-sensitive expression differences between sensitive and tolerant plants, three loci contained SNPs that are associated with both Al tolerance and soil acidity: an Al-sensitive malate transporter (ALMT), a tonoplast intrinsic protein (TIP) and the putative homolog of the rice cell-wall modification gene STAR1. Natural genetic variation at these loci is likely to have contributed to the recent rapid evolution at PGE. Continued study of Al tolerance variants in Anthoxanthum will allow us to test hypotheses about the nature and source of genetic variation that enables some species to adapt to soil acidification and other types of rapid environmental change. © 2014 John Wiley & Sons Ltd.

Identification and paleoclimatic significance of magnetite nanoparticles in soils

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Ahmed, Imad A. M.; Maher, Barbara A.

2018-02-01

In the world-famous sediments of the Chinese Loess Plateau, fossil soils alternate with windblown dust layers to record monsoonal variations over the last ˜3 My. The less-weathered, weakly magnetic dust layers reflect drier, colder glaciations. The fossil soils (paleosols) contain variable concentrations of nanoscale, strongly magnetic iron oxides, formed in situ during the wetter, warmer interglaciations. Mineralogical identification of the magnetic soil oxides is essential for deciphering these key paleoclimatic records. Formation of magnetite, a mixed Fe2+/Fe3+ ferrimagnet, has been linked to soil redox oscillations, and thence to paleorainfall. An opposite hypothesis states that magnetite can only form if the soil is water saturated for significant periods in order for Fe3+ to be reduced to Fe2+, and suggests instead the temperature-dependent formation of maghemite, an Fe3+-oxide, much of which ages subsequently into hematite, typically aluminum substituted. This latter, oxidizing pathway would have been temperature, but not rainfall dependent. Here, through structural fingerprinting and scanning transmission electron microscopy and electron energy loss spectroscopy analysis, we prove that magnetite is the dominant soil-formed ferrite. Maghemite is present in lower concentrations, and shows no evidence of aluminum substitution, negating its proposed precursor role for the aluminum-substituted hematite prevalent in the paleosols. Magnetite dominance demonstrates that magnetite formation occurs in well-drained, generally oxidizing soils, and that soil wetting/drying oscillations drive the degree of soil magnetic enhancement. The magnetic variations of the Chinese Loess Plateau paleosols thus record changes in monsoonal rainfall, over timescales of millions of years.

Enzyme immunoassay for DDT analysis in Lebanese soils

International Nuclear Information System (INIS)

Bashour, I.; Dagher, S.; Shammas, G.; Sukkariyah, B.; Kawar, N.

2000-01-01

Full text: The use of enzyme-linked immunosorbent assay (ELISA) technique in estimating pesticide residue in soils is a faster, less expensive and easier method to use than the gas chromatography (GC) analysis technique..In the test, DDT pesticide residues in the simple compete with enzyme (horseradish peroxidase)-labeled DDT for a limited number of antibody binding sites on the inside surfaces of the test wells; the envirologix plate kit was tested for the measurement of total DDT in virgin and fortified (0-1000 ng g exp-1) soil samples of different properties from Lebanon. Extraction of DDT from soil was done by shaking the samples for 16 hours on a mechanical shaker with 90% methanol without any clean-up steps. Then the samples were allowed to stand for 30 minutes and an aliquot was taken from the clear supernatant. The DDT in the extract was measured in triplicate by GC and ELISA. The results indicated that the two techniques were highly correlated (r2 =0.9671-0.9973). Differences in soils physical and chemical properties did not accuracy of the detection limits of ELISA when compared to GC-ECD results. Immunoassay technique is a suitable method for rapid and accurate measurement of DDT residue in mineral Lebanese soils

Soil nitrate reducing processes – drivers, mechanisms for spatial variation, and significance for nitrous oxide production

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Giles, Madeline; Morley, Nicholas; Baggs, Elizabeth M.; Daniell, Tim J.

2012-01-01

The microbial processes of denitrification and dissimilatory nitrate reduction to ammonium (DNRA) are two important nitrate reducing mechanisms in soil, which are responsible for the loss of nitrate (NO3−) and production of the potent greenhouse gas, nitrous oxide (N2O). A number of factors are known to control these processes, including O2 concentrations and moisture content, N, C, pH, and the size and community structure of nitrate reducing organisms responsible for the processes. There is an increasing understanding associated with many of these controls on flux through the nitrogen cycle in soil systems. However, there remains uncertainty about how the nitrate reducing communities are linked to environmental variables and the flux of products from these processes. The high spatial variability of environmental controls and microbial communities across small sub centimeter areas of soil may prove to be critical in determining why an understanding of the links between biotic and abiotic controls has proved elusive. This spatial effect is often overlooked as a driver of nitrate reducing processes. An increased knowledge of the effects of spatial heterogeneity in soil on nitrate reduction processes will be fundamental in understanding the drivers, location, and potential for N2O production from soils. PMID:23264770

Soil nitrate reducing processes – drivers, mechanisms for spatial variation and significance for nitrous oxide production

Directory of Open Access Journals (Sweden)

Madeline Eleanore Giles

2012-12-01

Full Text Available The microbial processes of denitrification and dissimilatory nitrate reduction to ammonium (DNRA are two important nitrate reducing mechanisms in soil, which are responsible for the loss of nitrate (NO3-¬ and production of the potent greenhouse gas, nitrous oxide (N2O. A number of factors are known to control these processes, including O2 concentrations and moisture content, N, C, pH and the size and community structure of nitrate reducing organisms responsible for the processes. There is an increasing understanding associated with many of these controls on flux through the nitrogen cycle in soil systems. However, there remains uncertainty about how the nitrate reducing communities are linked to environmental variables and the flux of products from these processes. The high spatial variability of environmental controls and microbial communities across small sub cm areas of soil may prove to be critical in determining why an understanding of the links between biotic and abiotic controls has proved elusive. This spatial effect is often overlooked as a driver of nitrate reducing processes. An increased knowledge of the effects of spatial heterogeneity in soil on nitrate reduction processes will be fundamental in understanding the drivers, location and potential for N2O production from soils.

The ties that bind: Soil surveyor William Edgar Tharp and oceanographic cartographer Marie Tharp

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Landa, Edward R.

The link between soil science and geology is personified in the American father and daughter: soil surveyor William Edgar Tharp (1870-1959) and oceanographic cartographer Marie Tharp (1920-2006). From 1904 to 1935, W.E. Tharp mapped soils in 14 states for the US Department of Agriculture, and campaigned during the late 1920s-early 1930s to raise awareness of the high rates of soil erosion from croplands. The lifestyle of the federal soil surveyor in the United States during the early 20th century involved frequent household moves, and it played a formative role in Marie Tharp’s childhood. Her path to a career in geology was molded by this family experience, by mentors encountered in the classroom, and by social barriers that faced women scientists of that era.

Linking soil DOC production rates and transport processes from landscapes to sub-basin scales

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Tian, Y. Q.; Yu, Q.; Li, J.; Ye, C.

2014-12-01

Recent research rejects the traditional perspective that dissolved organic carbon (DOC) component in global carbon cycle are simply trivial, and in fact evidence demonstrates that lakes likely mediate carbon dynamics on a global scale. Riverine and estuarine carbon fluxes play a critical role in transporting and recycling carbon and nutrients, not only within watersheds but in their receiving waters. However, the underlying mechanisms that drive carbon fluxes, from land to rivers, lake and oceans, remain poorly understood. This presentation will report a research result of the scale-dependent DOC production rate in coastal watersheds and DOC transport processes in estuarine regions. We conducted a series of controlled experiments and field measurements for examining biogeochemical, biological, and geospatial variables that regulate downstream processing on global-relevant carbon fluxes. Results showed that increased temperatures and raised soil moistures accelerate decomposition rates of organic matter with significant variations between vegetation types. The measurements at meso-scale ecosystem demonstrated a good correlation to bulk concentration of DOC monitored in receiving waters at the outlets of sub-basins (R2 > 0.65). These field and experimental measurements improved the model of daily carbon exports through below-ground processes as a function of the organic matter content of surface soils, forest litter supply, and temperature. The study demonstrated a potential improvement in modeling the co-variance of CDOM and DOC with the unique terrestrial sources. This improvement indicated a significant promise for monitoring riverine and estuarine carbon flux from satellite images. The technical innovations include deployments of 1) mini-ecosystem (mesocosms) with soil as replicate controlled experiments for DOC production and leaching rates, and 2) aquatic mesocosms for co-variances of DOC and CDOM endmembers, and an instrumented incubation experiment for

The effect of moisture content on the thermal conductivity of moss and organic soil horizons from black spruce ecosystems in interior Alaska

Science.gov (United States)

Jonathan A. O' Donnell; Vladimir E. Romanovsky; Jennifer W. Harden; A. David. McGuire

2009-01-01

Organic soil horizons function as important controls on the thermal state of near-surface soil and permafrost in high-latitude ecosystems. The thermal conductivity of organic horizons is typically lower than mineral soils and is closely linked to moisture content, bulk density, and water phase. In this study, we examined the relationship between thermal conductivity...

Soil physical properties affecting soil erosion in tropical soils

International Nuclear Information System (INIS)

Lobo Lujan, D.

2004-01-01

The total vegetated land area of the earth is about 11,500 hectare. Of this, about 12% is in South America. Of this, about 14% is degraded area. Water erosion, chemical degradation, wind erosion, and physical degradation have been reported as main types of degradation. In South America water erosion is a major process for soil degradation. Nevertheless, water erosion can be a consequence of degradation of the soil structure, especially the functional attributes of soil pores to transmit and retain water, and to facilitate root growth. Climate, soil and topographic characteristics determine runoff and erosion potential from agricultural lands. The main factors causing soil erosion can be divided into three groups: Energy factors: rainfall erosivity, runoff volume, wind strength, relief, slope angle, slope length; Protection factors: population density, plant cover, amenity value (pressure for use) and land management; and resistance factors: soil erodibility, infiltration capacity and soil management. The degree of soil erosion in a particular climatic zone, with particular soils, land use and socioeconomic conditions, will always result from a combination of the above mentioned factors. It is not easy to isolate a single factor. However, the soil physical properties that determine the soil erosion process, because the deterioration of soil physical properties is manifested through interrelated problems of surface sealing, crusting, soil compaction, poor drainage, impeded root growth, excessive runoff and accelerated erosion. When an unprotected soil surface is exposed to the direct impact of raindrops it can produce different responses: Production of smaller aggregates, dispersed particles, particles in suspension and translocation and deposition of particles. When this has occurred, the material is reorganized at the location into a surface seal. Aggregate breakdown under rainfall depends on soil strength and a certain threshold kinetic energy is needed to start

Relationships among Contrasting Measurements of Microbial Dynamics in Pasture and Organic Farm Soils

International Nuclear Information System (INIS)

Edenborn, S.L; Sexstone, A.J; Sutanto, Y; Chapman, J.A

2011-01-01

Soil bacteria exhibit short-term variations in community structure, providing an indication of anthropogenic disturbances. In this study, microbial biomass carbon (MBC), potentially mineralizable nitrogen (PMN), community level physiological profiling (CLPP), and culture-dependent DGGE (CD DGGE) fingerprinting of the 16 S r RNA gene were used to compare microbial communities in organic farm and pasture soils subjected to differing agronomic treatments. Correlation analyses revealed significant relationships between MBC, PMN, and data derived from microbial community analyses. All measures separated soil types but varied in their ability to distinguish among treatments within a soil type. Overall, MBC, PMN, and CLPP were most responsive to compost and manure amendments, while CD DGGE resolved differences in legume cropping and inorganic fertilization. The results support the hypothesis that culturable soil bacteria are a responsive fraction of the total microbial community, sensitive to agronomic perturbations and amenable to further studies aimed at linking community structure with soil functions.

Soil microbial communities drive the resistance of ecosystem multifunctionality to global change in drylands across the globe.

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Delgado-Baquerizo, Manuel; Eldridge, David J; Ochoa, Victoria; Gozalo, Beatriz; Singh, Brajesh K; Maestre, Fernando T

2017-10-01

The relationship between soil microbial communities and the resistance of multiple ecosystem functions linked to C, N and P cycling (multifunctionality resistance) to global change has never been assessed globally in natural ecosystems. We collected soils from 59 dryland ecosystems worldwide to investigate the importance of microbial communities as predictor of multifunctionality resistance to climate change and nitrogen fertilisation. Multifunctionality had a lower resistance to wetting-drying cycles than to warming or N deposition. Multifunctionality resistance was regulated by changes in microbial composition (relative abundance of phylotypes) but not by richness, total abundance of fungi and bacteria or the fungal: bacterial ratio. Our results suggest that positive effects of particular microbial taxa on multifunctionality resistance could potentially be controlled by altering soil pH. Together, our work demonstrates strong links between microbial community composition and multifunctionality resistance in dryland soils from six continents, and provides insights into the importance of microbial community composition for buffering effects of global change in drylands worldwide. © 2017 John Wiley & Sons Ltd/CNRS.

Time series modeling of soil moisture dynamics on a steep mountainous hillside

Science.gov (United States)

Kim, Sanghyun

2016-05-01

The response of soil moisture to rainfall events along hillslope transects is an important hydrologic process and a critical component of interactions between soil vegetation and the atmosphere. In this context, the research described in this article addresses the spatial distribution of soil moisture as a function of topography. In order to characterize the temporal variation in soil moisture on a steep mountainous hillside, a transfer function, including a model for noise, was introduced. Soil moisture time series with similar rainfall amounts, but different wetness gradients were measured in the spring and fall. Water flux near the soil moisture sensors was modeled and mathematical expressions were developed to provide a basis for input-output modeling of rainfall and soil moisture using hydrological processes such as infiltration, exfiltration and downslope lateral flow. The characteristics of soil moisture response can be expressed in terms of model structure. A seasonal comparison of models reveals differences in soil moisture response to rainfall, possibly associated with eco-hydrological process and evapotranspiration. Modeling results along the hillslope indicate that the spatial structure of the soil moisture response patterns mainly appears in deeper layers. Similarities between topographic attributes and stochastic model structures are spatially organized. The impact of temporal and spatial discretization scales on parameter expression is addressed in the context of modeling results that link rainfall events and soil moisture.

HONO (nitrous acid) emissions from acidic northern soils

Science.gov (United States)

Maljanen, Marja; Yli-Pirilä, Pasi; Joutsensaari, Jorma; Martikainen, Pertti J.

2015-04-01

The photolysis of HONO (nitrous acid) is an important source of OH radical, the key oxidizing agent in the atmosphere, contributing also to removal of atmospheric methane (CH4), the second most important greenhouse gas after carbon dioxide (CO2). The emissions of HONO from soils have been recently reported in few studies. Soil HONO emissions are regarded as missing sources of HONO when considering the chemical reactions in the atmosphere. The soil-derived HONO has been connected to soil nitrite (NO2-) and also directly to the activity of ammonia oxidizing bacteria, which has been studied with one pure culture. Our hypothesis was that boreal acidic soils with high nitrification activity could be also sources of HONO and the emissions of HONO are connected with nitrification. We selected a range of dominant northern acidic soils and showed in microcosm experiments that soils which have the highest nitrous oxide (N2O) and nitric oxide (NO) emissions (drained peatlands) also have the highest HONO production rates. The emissions of HONO are thus linked to nitrogen cycle and also NO and N2O emissions. Natural peatlands and boreal coniferous forests on mineral soils had the lowest HONO emissions. It is known that in natural peatlands with high water table and in boreal coniferous forest soils, low nitrification activity (microbial production of nitrite and nitrate) limits their N2O production. Low availability of nitrite in these soils is the likely reason also for their low HONO production rates. We also studied the origin of HONO in one peat soil with acetylene and other nitrification inhibitors and we found that HONO production is not closely connected to ammonium oxidation (nitrification). Acetylene blocked NO emissions but did not affect HONO or N2O emissions, thus there is another source behind HONO emission from these soils than ammonium oxidation. It is still an open question if this process is microbial or chemical origin.

Mycorrhiza-mediated competition between plants and decomposers drives soil carbon storage.

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Averill, Colin; Turner, Benjamin L; Finzi, Adrien C

2014-01-23

Soil contains more carbon than the atmosphere and vegetation combined. Understanding the mechanisms controlling the accumulation and stability of soil carbon is critical to predicting the Earth's future climate. Recent studies suggest that decomposition of soil organic matter is often limited by nitrogen availability to microbes and that plants, via their fungal symbionts, compete directly with free-living decomposers for nitrogen. Ectomycorrhizal and ericoid mycorrhizal (EEM) fungi produce nitrogen-degrading enzymes, allowing them greater access to organic nitrogen sources than arbuscular mycorrhizal (AM) fungi. This leads to the theoretical prediction that soil carbon storage is greater in ecosystems dominated by EEM fungi than in those dominated by AM fungi. Using global data sets, we show that soil in ecosystems dominated by EEM-associated plants contains 70% more carbon per unit nitrogen than soil in ecosystems dominated by AM-associated plants. The effect of mycorrhizal type on soil carbon is independent of, and of far larger consequence than, the effects of net primary production, temperature, precipitation and soil clay content. Hence the effect of mycorrhizal type on soil carbon content holds at the global scale. This finding links the functional traits of mycorrhizal fungi to carbon storage at ecosystem-to-global scales, suggesting that plant-decomposer competition for nutrients exerts a fundamental control over the terrestrial carbon cycle.

ACCUMULATION OF POLY-B-HYDROXYBUTYRATE IN A METHANE- ENRICHED, HALOGENATED, HYDROCARBON-DEGRADING SOIL COLUMN: IMPLICATIONS FOR MICROBIAL COMMUNITY STRUCTURE AND NUTRITIONAL STATUS

Science.gov (United States)

The prokarotic, endogenous storage polymer poly--hydroxybutyrate (PHB) accumulated in soil from a methane-enriched, halogenated hydrocarbon-degrading soil column. Based on phospholipid ester-linked fatty acid (PLFA) profiles, this mocrocosm has been previously reported to be sign...

Interannual variability of plant phenology in tussock tundra: modelling interactions of plant productivity, plant phenology, snowmelt and soil thaw

NARCIS (Netherlands)

Wijk, van M.T.; Williams, M.; Laundre, J.A.; Shaver, G.R.

2003-01-01

We present a linked model of plant productivity, plant phenology, snowmelt and soil thaw in order to estimate interannual variability of arctic plant phenology and its effects on plant productivity. The model is tested using 8 years of soil temperature data, and three years of bud break data of

[Ecological hygienic assessment of soils quality in urban areas].

Science.gov (United States)

Vodyanova, M A; Kriatov, I A; Donerian, L G; Evseeva, I S; Ushakov, D I; Sbitnev, A V

Assessment of the soil quality is ofprime importance essential for the characterization of the ecological and hygienic condition of the territory, as the soil is the first link of the food chain, the source of secondary air and water pollution, as well as an integral index of ecological well-being of the environment. Herewith the qualitative analysis of soil complicated by the specifics of the soil genesis in the urban environment, in which an important role is played by manmade land bulk and alluvial soils; the inclusion of construction of material debris and household garbage in upper horizons; the growing up of the profile due to the perpetual introduction of different materials and intensive aeolian deposition. It is advisable to consider the currently neglected question of the study of soil vapor containing volatile chemicals. These pollutants penetrate into the building through cracks in the foundation and openings for utilities. Soil evaporation may accumulate in residential areas or in the soil under the building. Because of this, it is necessary to pay attention to the remediation of areas allocated for the built-up area, possessing a large-scale underground parking. Soil contamination is the result of significant anthropogenic impacts on the environment components. In general, about 89.1 million people (62.6% of the population of the country) live in terms of complex chemical load, determined by contamination offood, drinking water, air and soil. The list of microbiological and sanitary-chemical indices of the assessment of soils of urban areas may vary in dependence on the data obtained in pilot studies due to changes and additions to the assigned tasks. Timely forecast for the possibility of the usage of released lands of urban territories for the construction and the creation of new objects for different purposes should become the prevention of chronic non-infectious diseases in the population residing in urban areas.

Contrasting elevational diversity patterns for soil bacteria between two ecosystems divided by the treeline.

Science.gov (United States)

Li, Guixiang; Xu, Guorui; Shen, Congcong; Tang, Yong; Zhang, Yuxin; Ma, Keming

2016-11-01

Above- and below-ground organisms are closely linked, but how elevational distribution pattern of soil microbes shifting across the treeline still remains unknown. Sampling of 140 plots with transect, we herein investigated soil bacterial distribution pattern from a temperate forest up to a subalpine meadow along an elevational gradient using Illumina sequencing. Our results revealed distinct elevational patterns of bacterial diversity above and below the treeline in responding to changes in soil conditions: a hollow elevational pattern in the forest (correlated with soil temperature, pH, and C:N ratio) and a significantly decreasing pattern in the meadow (correlated with soil pH, and available phosphorus). The bacterial community structure was also distinct between the forest and meadow, relating to soil pH in the forest and soil temperature in the meadow. Soil bacteria did not follow the distribution pattern of herb diversity, but bacterial community structure could be predicted by herb community composition. These results suggest that plant communities have an important influence on soil characteristics, and thus change the elevational distribution of soil bacteria. Our findings are useful for future assessments of climate change impacts on microbial community.

Pathogen Decontamination of Food Crop Soil: A Review.

Science.gov (United States)

Gurtler, Joshua B

2017-09-01

The purpose of this review is to delineate means of decontaminating soil. This information might be used to mitigate soil-associated risks of foodborne pathogens. The majority of the research in the published literature involves inactivation of plant pathogens in soil, i.e., those pathogens harmful to fruit and vegetable production and ornamental plants. Very little has been published regarding the inactivation of foodborne human pathogens in crop soil. Nevertheless, because decontamination techniques for plant pathogens might also be useful methods for eliminating foodborne pathogens, this review also includes inactivation of plant pathogens, with appropriate discussion and comparisons, in the hopes that these methods may one day be validated against foodborne pathogens. Some of the major soil decontamination methods that have been investigated and are covered include chemical decontamination (chemigation), solarization, steaming, biofumigation, bacterial competitive exclusion, torch flaming, microwave treatment, and amendment with biochar. Other innovative means of inactivating foodborne pathogens in soils may be discovered and explored in the future, provided that these techniques are economically feasible in terms of chemicals, equipment, and labor. Food microbiology and food safety researchers should reach out to soil scientists and plant pathologists to create links where they do not currently exist and strengthen relationships where they do exist to take advantage of multidisciplinary skills. In time, agricultural output and the demand for fresh produce will increase. With advances in the sensitivity of pathogen testing and epidemiological tracebacks, the need to mitigate preharvest bacterial contamination of fresh produce will become paramount. Hence, soil decontamination technologies may become more economically feasible and practical in light of increasing the microbial safety of fresh produce.

Variation of the distribution coefficient (Kd) of selenium in soils under various microbial states

International Nuclear Information System (INIS)

Fevrier, L.; Martin-Garin, A.; Leclerc, E.

2007-01-01

This study aimed to (i) evaluate whether the K d value of selenium is dependent upon the soil microbial activity and (ii) define the limitation of the use of the K d concept to describe selenium behaviour in soils when assessing the long-term radiological waste disposal risk. K d coefficients, as well as information on selenite speciation in the soil-solution, were derived from short- and long-term batch experiments with a calcareous silty clay soil in various microbial states. Soil microbial activity induced (i) an increase of the K d value from 16 l kg -1 in sterile conditions to 130 l kg -1 when the soil was amended with glucose and nitrate, and (ii) changes in selenium speciation both in the solution (presence of seleno-species other than free Se(IV)) and in the solid phase (Se linked to microorganisms). Although the K d coefficient adequately reflects the initial fractionation between soil-solid and soil-solution, it does not allow for speciation and microbial processes, which could affect reversibility, mobility and the long-term accumulation and uptake into crops

Links between plant litter chemistry, species diversity, and below-ground ecosystem function.

Science.gov (United States)

Meier, Courtney L; Bowman, William D

2008-12-16

Decomposition is a critical source of plant nutrients, and drives the largest flux of terrestrial C to the atmosphere. Decomposing soil organic matter typically contains litter from multiple plant species, yet we lack a mechanistic understanding of how species diversity influences decomposition processes. Here, we show that soil C and N cycling during decomposition are controlled by the composition and diversity of chemical compounds within plant litter mixtures, rather than by simple metrics of plant species diversity. We amended native soils with litter mixtures containing up to 4 alpine plant species, and we used 9 litter chemical traits to evaluate the chemical composition (i.e., the identity and quantity of compounds) and chemical diversity of the litter mixtures. The chemical composition of the litter mixtures was the strongest predictor of soil respiration, net N mineralization, and microbial biomass N. Soil respiration and net N mineralization rates were also significantly correlated with the chemical diversity of the litter mixtures. In contrast, soil C and N cycling rates were poorly correlated with plant species richness, and there was no relationship between species richness and the chemical diversity of the litter mixtures. These results indicate that the composition and diversity of chemical compounds in litter are potentially important functional traits affecting decomposition, and simple metrics like plant species richness may fail to capture variation in these traits. Litter chemical traits therefore provide a mechanistic link between organisms, species diversity, and key components of below-ground ecosystem function.

Responses of seminal wheat seedling roots to soil water deficits.

Science.gov (United States)

Trejo, Carlos; Else, Mark A; Atkinson, Christopher J

2018-04-01

The aims of this paper are to develop our understanding of the ways by which soil water deficits influence early wheat root growth responses, particularly how seminal roots respond to soil drying and the extent to which information on differences in soil water content are conveyed to the shoot and their impact on shoot behaviour. To achieve this, wheat seedlings have been grown, individually for around 25 days after germination in segmented soil columns within vertical plastic compartments. Roots were exposed to different soil volumetric moisture contents (SVMC) within the two compartments. Experiments where the soil in the lower compartment was allowed to dry to different extents, while the upper was maintained close to field capacity, showed that wheat seedlings allocated proportionally more root dry matter to the lower drier soil compartment. The total production of root, irrespective of the upper or lower SVMC, was similar and there were no detected effects on leaf growth rate or gas exchange. The response of seminal roots to proportionally increase their allocation of dry matter, to the drier soil was unexpected with such plasticity of roots system development traditionally linked to heterogeneous nutrient distribution than accessing soil water. In experiments where the upper soil compartment was allowed to dry, root growth slowed and leaf growth and gas exchange declined. Subsequent experiments used root growth rates to determine when seminal root tips first came into contact with drying soil, with the intentions of determining how the observed root growth rates were maintained as an explanation for the observed changes in root allocation. Measurements of seminal root ABA and ethylene from roots within the drying soil are interpreted with respect to what is known about the physiological control of root growth in drying soil. Copyright © 2018 Elsevier GmbH. All rights reserved.

Soil microbiome responses to the short-term effects of Amazonian deforestation.

Science.gov (United States)

Navarrete, Acacio A; Tsai, Siu M; Mendes, Lucas W; Faust, Karoline; de Hollander, Mattias; Cassman, Noriko A; Raes, Jeroen; van Veen, Johannes A; Kuramae, Eiko E

2015-05-01

Slash-and-burn clearing of forest typically results in increase in soil nutrient availability. However, the impact of these nutrients on the soil microbiome is not known. Using next generation sequencing of 16S rRNA gene and shotgun metagenomic DNA, we compared the structure and the potential functions of bacterial community in forest soils to deforested soils in the Amazon region and related the differences to soil chemical factors. Deforestation decreased soil organic matter content and factors linked to soil acidity and raised soil pH, base saturation and exchangeable bases. Concomitant to expected changes in soil chemical factors, we observed an increase in the alpha diversity of the bacterial microbiota and relative abundances of putative copiotrophic bacteria such as Actinomycetales and a decrease in the relative abundances of bacterial taxa such as Chlamydiae, Planctomycetes and Verrucomicrobia in the deforested soils. We did not observe an increase in genes related to microbial nutrient metabolism in deforested soils. However, we did observe changes in community functions such as increases in DNA repair, protein processing, modification, degradation and folding functions, and these functions might reflect adaptation to changes in soil characteristics due to forest clear-cutting and burning. In addition, there were changes in the composition of the bacterial groups associated with metabolism-related functions. Co-occurrence microbial network analysis identified distinct phylogenetic patterns for forest and deforested soils and suggested relationships between Planctomycetes and aluminium content, and Actinobacteria and nitrogen sources in Amazon soils. The results support taxonomic and functional adaptations in the soil bacterial community following deforestation. We hypothesize that these microbial adaptations may serve as a buffer to drastic changes in soil fertility after slash-and-burning deforestation in the Amazon region. © 2015 John Wiley & Sons Ltd.

Soil Conditions Rather Than Long-Term Exposure to Elevated CO2 Affect Soil Microbial Communities Associated with N-Cycling

Directory of Open Access Journals (Sweden)

Kristof Brenzinger

2017-10-01

Full Text Available Continuously rising atmospheric CO2 concentrations may lead to an increased transfer of organic C from plants to the soil through rhizodeposition and may affect the interaction between the C- and N-cycle. For instance, fumigation of soils with elevated CO2 (eCO2 concentrations (20% higher compared to current atmospheric concentrations at the Giessen Free-Air Carbon Dioxide Enrichment (GiFACE sites resulted in a more than 2-fold increase of long-term N2O emissions and an increase in dissimilatory reduction of nitrate compared to ambient CO2 (aCO2. We hypothesized that the observed differences in soil functioning were based on differences in the abundance and composition of microbial communities in general and especially of those which are responsible for N-transformations in soil. We also expected eCO2 effects on soil parameters, such as on nitrate as previously reported. To explore the impact of long-term eCO2 on soil microbial communities, we applied a molecular approach (qPCR, T-RFLP, and 454 pyrosequencing. Microbial groups were analyzed in soil of three sets of two FACE plots (three replicate samples from each plot, which were fumigated with eCO2 and aCO2, respectively. N-fixers, denitrifiers, archaeal and bacterial ammonia oxidizers, and dissimilatory nitrate reducers producing ammonia were targeted by analysis of functional marker genes, and the overall archaeal community by 16S rRNA genes. Remarkably, soil parameters as well as the abundance and composition of microbial communities in the top soil under eCO2 differed only slightly from soil under aCO2. Wherever differences in microbial community abundance and composition were detected, they were not linked to CO2 level but rather determined by differences in soil parameters (e.g., soil moisture content due to the localization of the GiFACE sets in the experimental field. We concluded that +20% eCO2 had little to no effect on the overall microbial community involved in N-cycling in the

Soil Conditions Rather Than Long-Term Exposure to Elevated CO2 Affect Soil Microbial Communities Associated with N-Cycling.

Science.gov (United States)

Brenzinger, Kristof; Kujala, Katharina; Horn, Marcus A; Moser, Gerald; Guillet, Cécile; Kammann, Claudia; Müller, Christoph; Braker, Gesche

2017-01-01

Continuously rising atmospheric CO 2 concentrations may lead to an increased transfer of organic C from plants to the soil through rhizodeposition and may affect the interaction between the C- and N-cycle. For instance, fumigation of soils with elevated CO 2 ( e CO 2 ) concentrations (20% higher compared to current atmospheric concentrations) at the Giessen Free-Air Carbon Dioxide Enrichment (GiFACE) sites resulted in a more than 2-fold increase of long-term N 2 O emissions and an increase in dissimilatory reduction of nitrate compared to ambient CO 2 ( a CO 2 ). We hypothesized that the observed differences in soil functioning were based on differences in the abundance and composition of microbial communities in general and especially of those which are responsible for N-transformations in soil. We also expected e CO 2 effects on soil parameters, such as on nitrate as previously reported. To explore the impact of long-term e CO 2 on soil microbial communities, we applied a molecular approach (qPCR, T-RFLP, and 454 pyrosequencing). Microbial groups were analyzed in soil of three sets of two FACE plots (three replicate samples from each plot), which were fumigated with e CO 2 and a CO 2 , respectively. N-fixers, denitrifiers, archaeal and bacterial ammonia oxidizers, and dissimilatory nitrate reducers producing ammonia were targeted by analysis of functional marker genes, and the overall archaeal community by 16S rRNA genes. Remarkably, soil parameters as well as the abundance and composition of microbial communities in the top soil under e CO 2 differed only slightly from soil under a CO 2 . Wherever differences in microbial community abundance and composition were detected, they were not linked to CO 2 level but rather determined by differences in soil parameters (e.g., soil moisture content) due to the localization of the GiFACE sets in the experimental field. We concluded that +20% e CO 2 had little to no effect on the overall microbial community involved in N

Assimilation of microwave brightness temperatures for soil moisture estimation using particle filter

International Nuclear Information System (INIS)

Bi, H Y; Ma, J W; Qin, S X; Zeng, J Y

2014-01-01

Soil moisture plays a significant role in global water cycles. Both model simulations and remote sensing observations have their limitations when estimating soil moisture on a large spatial scale. Data assimilation (DA) is a promising tool which can combine model dynamics and remote sensing observations to obtain more precise ground soil moisture distribution. Among various DA methods, the particle filter (PF) can be applied to non-linear and non-Gaussian systems, thus holding great potential for DA. In this study, a data assimilation scheme based on the residual resampling particle filter (RR-PF) was developed to assimilate microwave brightness temperatures into the macro-scale semi-distributed Variance Infiltration Capacity (VIC) Model to estimate surface soil moisture. A radiative transfer model (RTM) was used to link brightness temperatures with surface soil moisture. Finally, the data assimilation scheme was validated by experimental data obtained at Arizona during the Soil Moisture Experiment 2004 (SMEX04). The results show that the estimation accuracy of soil moisture can be improved significantly by RR-PF through assimilating microwave brightness temperatures into VIC model. Both the overall trends and specific values of the assimilation results are more consistent with ground observations compared with model simulation results

Soil and Soil Water Relationships

OpenAIRE

Easton, Zachary M.; Bock, Emily

2017-01-01

Discusses the relationships between soil, water and plants. Discusses different types of soil, and how these soils hold water. Provides information about differences in soil drainage. Discusses the concept of water balance.

A Canadian upland forest soil profile and carbon stocks database.

Science.gov (United States)

Shaw, Cindy; Hilger, Arlene; Filiatrault, Michelle; Kurz, Werner

2018-04-01

"A Canadian upland forest soil profile and carbon stocks database" was compiled in phases over a period of 10 years to address various questions related to modeling upland forest soil carbon in a national forest carbon accounting model. For 3,253 pedons, the SITES table contains estimates for soil organic carbon stocks (Mg/ha) in organic horizons and mineral horizons to a 100-cm depth, soil taxonomy, leading tree species, mean annual temperature, annual precipitation, province or territory, terrestrial ecozone, and latitude and longitude, with an assessment of the quality of information about location. The PROFILES table contains profile data (16,167 records by horizon) used to estimate the carbon stocks that appear in the SITES table, plus additional soil chemical and physical data, where provided by the data source. The exceptions to this are estimates for soil carbon stocks based on Canadian National Forest Inventory data (NFI [2006] in REFERENCES table), where data were collected by depth increment rather than horizon and, therefore, total soil carbon stocks were calculated separately before being entered into the SITES table. Data in the PROFILES table include the carbon stock estimate for each horizon (corrected for coarse fragment content), and the data used to calculate the carbon stock estimate, such as horizon thickness, bulk density, and percent organic carbon. The PROFILES table also contains data, when reported by the source, for percent carbonate carbon, pH, percent total nitrogen, particle size distribution (percent sand, silt, clay), texture class, exchangeable cations, cation and total exchange capacity, and percent Fe and Al. An additional table provides references (REFERENCES table) for the source data. Earlier versions of the database were used to develop national soil carbon modeling categories based on differences in carbon stocks linked to soil taxonomy and to examine the potential of using soil taxonomy and leading tree species to improve