Water Market-scale Agricultural Planning: Promoting Competing Water Resource Use Efficiency Through Agro-Economics

Science.gov (United States)

Delorit, J. D.; Block, P. J.

2017-12-01

Where strong water rights law and corresponding markets exist as a coupled econo-legal mechanism, water rights holders are permitted to trade allocations to promote economic water resource use efficiency. In locations where hydrologic uncertainty drives the assignment of annual per-water right allocation values by water resource managers, collaborative water resource decision making by water rights holders, specifically those involved in agricultural production, can result in both resource and economic Pareto efficiency. Such is the case in semi-arid North Chile, where interactions between representative farmer groups, treated as competitive bilateral monopolies, and modeled at water market-scale, can provide both price and water right allocation distribution signals for unregulated, temporary water right leasing markets. For the range of feasible per-water right allocation values, a coupled agricultural-economic model is developed to describe the equilibrium distribution of water, the corresponding market price of water rights and the net surplus generated by collaboration between competing agricultural uses. Further, this research describes a per-water right inflection point for allocations where economic efficiency is not possible, and where price negotiation among competing agricultural uses is required. An investigation of the effects of water right supply and demand inequality at the market-scale is completed to characterize optimal market performance under existing water rights law. The broader insights of this research suggest that water rights holders engaged in agriculture can achieve economic benefits from forming crop-type cooperatives and by accurately assessing the economic value of allocation.

Gas exchanges and water use efficiency in the selection of tomato genotypes tolerant to water stress.

Science.gov (United States)

Borba, M E A; Maciel, G M; Fraga Júnior, E F; Machado Júnior, C S; Marquez, G R; Silva, I G; Almeida, R S

2017-06-20

Water stress can affect the yield in tomato crops and, despite this, there are few types of research aiming to select tomato genotypes resistant to the water stress using physiological parameters. This experiment aimed to study the variables that are related to the gas exchanges and the efficiency in water use, in the selection of tomato genotypes tolerant to water stress. It was done in a greenhouse, measuring 7 x 21 m, in a randomized complete block design, with four replications (blocks), being five genotypes in the F 2 BC 1 generation, which were previously obtained from an interspecific cross between Solanum pennellii versus S. lycopersicum and three check treatments, two susceptible [UFU-22 (pre-commercial line) and cultivar Santa Clara] and one resistant (S. pennellii). At the beginning of flowering, the plants were submitted to a water stress condition, through irrigation suspension. After that CO 2 assimilation, internal CO 2 , stomatal conductance, transpiration, leaf temperature, instantaneous water use efficiency, intrinsic efficiency of water use, instantaneous carboxylation efficiency, chlorophyll a and b, and the potential leaf water (Ψf) were observed. Almost all variables that were analyzed, except CO 2 assimilation and instantaneous carboxylation efficiency, demonstrated the superiority of the wild accession, S. pennellii, concerning the susceptible check treatments. The high photosynthetic rate and the low stomatal conductance and transpiration, presented by the UFU22/F 2 BC 1 #2 population, allowed a better water use efficiency. Because of that, these physiological characteristics are promising in the selection of tomato genotypes tolerant to water stress.

Variable fuzzy assessment of water use efficiency and benefits in irrigation district

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Ming-hui Wang

2015-07-01

Full Text Available In order to scientifically and reasonably evaluate water use efficiency and benefits in irrigation districts, a variable fuzzy assessment model was established. The model can reasonably determine the relative membership degree and relative membership function of the sample indices in each index's standard interval, and obtain the evaluation level of the sample through the change of model parameters. According to the actual situation of the Beitun Irrigation District, which is located in Fuhai County, in Altay City, Xinjiang Uyghur Autonomous Region, five indices were selected as evaluation factors, including the canal water utilization coefficient, field water utilization coefficient, crop water productivity, effective irrigation rate in farmland, and water-saving irrigation area ratio. The water use efficiency and benefits in the Beitun Irrigation District in different years were evaluated with the model. The results showed that the comprehensive evaluation indices from 2006 to 2008 were all at the third level (medium efficiency, while the index in 2009 increased slightly, falling between the second level (relatively high efficiency and third level, indicating an improvement in the water use efficiency and benefits in the Beitun Irrigation District, which in turn showed that the model was reliable and easy to use. This model can be used to assess the water use efficiency and benefits in similar irrigation districts.

Water use efficiency studies of Acacia senegal (L.) Willd provenances in Sudan

International Nuclear Information System (INIS)

Mustafa, A.F.; Elamin, K.H.; Salih, A.A.

1996-01-01

An experiment was conducted in 1989 to screen Acacia senegal L. Willd provenances collected from within the natural gum belt for high water use efficiency. Thirteen provenances were tested for water use efficiency and consequently 6 out of them were selected for further screening. The selection was based on their performance in the preliminary screening. Both the preliminary and the detailed study revealed that provenances 7, 3 and 11 combine high dry matter production with high water use efficiency. Water use efficiency and dry matter production appears to be negatively correlated with root length density and root/shoot ratios. Provenances 7 which exhibited the highest water use efficiency and dry matter yield had the lowest root/shoot ratio and also a low root length density. Based on these studies provenance 7 can be considered a suitable candidate for introduction into gum-belt of Sudan through for rehabilitation of this region. (author). 5 refs, 1 fig., 3 tabs

Water use efficiency studies of Acacia senegal (L.) Willd provenances in Sudan

Energy Technology Data Exchange (ETDEWEB)

Mustafa, A F; Elamin, K H [Forestry Research Section, Wad Medani (Sudan); Salih, A A [Soil Science Section, Wad Medani (Sudan)

1996-07-01

An experiment was conducted in 1989 to screen Acacia senegal L. Willd provenances collected from within the natural gum belt for high water use efficiency. Thirteen provenances were tested for water use efficiency and consequently 6 out of them were selected for further screening. The selection was based on their performance in the preliminary screening. Both the preliminary and the detailed study revealed that provenances 7, 3 and 11 combine high dry matter production with high water use efficiency. Water use efficiency and dry matter production appears to be negatively correlated with root length density and root/shoot ratios. Provenances 7 which exhibited the highest water use efficiency and dry matter yield had the lowest root/shoot ratio and also a low root length density. Based on these studies provenance 7 can be considered a suitable candidate for introduction into gum-belt of Sudan through for rehabilitation of this region. (author). 5 refs, 1 fig., 3 tabs.

SEBAL Model Using to Estimate Irrigation Water Efficiency & Water Requirement of Alfalfa Crop

Science.gov (United States)

Zeyliger, Anatoly; Ermolaeva, Olga

2013-04-01

The sustainability of irrigation is a complex and comprehensive undertaking, requiring an attention to much more than hydraulics, chemistry, and agronomy. A special combination of human, environmental, and economic factors exists in each irrigated region and must be recognized and evaluated. A way to evaluate the efficiency of irrigation water use for crop production is to consider the so-called crop-water production functions, which express the relation between the yield of a crop and the quantity of water applied to it or consumed by it. The term has been used in a somewhat ambiguous way. Some authors have defined the Crop-Water Production Functions between yield and the total amount of water applied, whereas others have defined it as a relation between yield and seasonal evapotranspiration (ET). In case of high efficiency of irrigation water use the volume of water applied is less than the potential evapotranspiration (PET), then - assuming no significant change of soil moisture storage from beginning of the growing season to its end-the volume of water may be roughly equal to ET. In other case of low efficiency of irrigation water use the volume of water applied exceeds PET, then the excess of volume of water applied over PET must go to either augmenting soil moisture storage (end-of-season moisture being greater than start-of-season soil moisture) or to runoff or/and deep percolation beyond the root zone. In presented contribution some results of a case study of estimation of biomass and leaf area index (LAI) for irrigated alfalfa by SEBAL algorithm will be discussed. The field study was conducted with aim to compare ground biomass of alfalfa at some irrigated fields (provided by agricultural farm) at Saratov and Volgograd Regions of Russia. The study was conducted during vegetation period of 2012 from April till September. All the operations from importing the data to calculation of the output data were carried by eLEAF company and uploaded in Fieldlook web

Estimation of Transpiration and Water Use Efficiency Using Satellite and Field Observations

Science.gov (United States)

Choudhury, Bhaskar J.; Quick, B. E.

2003-01-01

Structure and function of terrestrial plant communities bring about intimate relations between water, energy, and carbon exchange between land surface and atmosphere. Total evaporation, which is the sum of transpiration, soil evaporation and evaporation of intercepted water, couples water and energy balance equations. The rate of transpiration, which is the major fraction of total evaporation over most of the terrestrial land surface, is linked to the rate of carbon accumulation because functioning of stomata is optimized by both of these processes. Thus, quantifying the spatial and temporal variations of the transpiration efficiency (which is defined as the ratio of the rate of carbon accumulation and transpiration), and water use efficiency (defined as the ratio of the rate of carbon accumulation and total evaporation), and evaluation of modeling results against observations, are of significant importance in developing a better understanding of land surface processes. An approach has been developed for quantifying spatial and temporal variations of transpiration, and water-use efficiency based on biophysical process-based models, satellite and field observations. Calculations have been done using concurrent meteorological data derived from satellite observations and four dimensional data assimilation for four consecutive years (1987-1990) over an agricultural area in the Northern Great Plains of the US, and compared with field observations within and outside the study area. The paper provides substantive new information about interannual variation, particularly the effect of drought, on the efficiency values at a regional scale.

Water Use and Water-Use Efficiency of Three Perennial Bioenergy Grass Crops in Florida

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Jerry M. Bennett

2012-10-01

Full Text Available Over two-thirds of human water withdrawals are estimated to be used for agricultural production, which is expected to increase as demand for renewable liquid fuels from agricultural crops intensifies. Despite the potential implications of bioenergy crop production on water resources, few data are available on water use of perennial bioenergy grass crops. Therefore, the objective of this study was to compare dry matter yield, water use, and water-use efficiency (WUE of elephantgrass, energycane, and giant reed, grown under field conditions for two growing seasons in North Central Florida. Using scaled sap flow sensor data, water use ranged from about 850 to 1150 mm during the growing season, and was generally greater for giant reed and less for elephantgrass. Despite similar or greater water use by giant reed, dry biomass yields of 35 to 40 Mg ha−1 were significantly greater for energycane and elephantgrass, resulting in greater WUE. Overall, water use by the bioenergy crops was greater than the rainfall received during the study, indicating that irrigation will be needed in the region to achieve optimal yields. Species differ in water use and WUE and species selection can play an important role with regard to potential consequences for water resources.

The effects of soil water conditions on nitrogen fertilization use efficiency

International Nuclear Information System (INIS)

Zhou Lingyun

1996-01-01

Concerning with applied nitrogen fertilizer, the uptake as well as loss of nitrogen is mainly related to soil water content. The effects of soil water condition in wheat field on the uptake, leach and loss of nitrogen fertilizer were studied using 15 N tracing technique. The results showed that within certain range of soil water supply, from 180 to 360 mm of available water storage, the loss of nitrogen was in direct proportion to the amount of fertilizer application and the nitrogen use efficiency decreased with the increase of nitrogen application. In other words, the nitrogen use efficiency descended with the nitrogen application increased in an order of 75 kgN/ha, 150 kgN/ha, 225 kgN/ha. One interesting result was that the nitrogen use efficiencies ranged from 17.0% to 30.5% for the treatments receiving the same application rate of 75 kgN/ha

Salicaceae Endophytes Modulate Stomatal Behavior and Increase Water Use Efficiency in Rice

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Hyungmin Rho

2018-03-01

Full Text Available Bacterial and yeast endophytes isolated from the Salicaceae family have been shown to promote growth and alleviate stress in plants from different taxa. To determine the physiological pathways through which endophytes affect plant water relations, we investigated leaf water potential, whole-plant water use, and stomatal responses of rice plants to Salicaceae endophyte inoculation under CO2 enrichment and water deficit. Daytime stomatal conductance and stomatal density were lower in inoculated plants compared to controls. Leaf ABA concentrations increased with endophyte inoculation. As a result, transpirational water use decreased significantly with endophyte inoculation while biomass did not change or slightly increased. This response led to a significant increase in cumulative water use efficiency at harvest. Different endophyte strains produced the same results in host plant water relations and stomatal responses. These stomatal responses were also observed under elevated CO2 conditions, and the increase in water use efficiency was more pronounced under water deficit conditions. The effect on water use efficiency was positively correlated with daily light integrals across different experiments. Our results provide insights on the physiological mechanisms of plant-endophyte interactions involving plant water relations and stomatal functions.

Automated Irrigation System using Weather Prediction for Efficient Usage of Water Resources

Science.gov (United States)

Susmitha, A.; Alakananda, T.; Apoorva, M. L.; Ramesh, T. K.

2017-08-01

In agriculture the major problem which farmers face is the water scarcity, so to improve the usage of water one of the irrigation system using drip irrigation which is implemented is “Automated irrigation system with partition facility for effective irrigation of small scale farms” (AISPF). But this method has some drawbacks which can be improved and here we are with a method called “Automated irrigation system using weather prediction for efficient usage of water resources’ (AISWP), it solves the shortcomings of AISPF process. AISWP method helps us to use the available water resources more efficiently by sensing the moisture present in the soil and apart from that it is actually predicting the weather by sensing two parameters temperature and humidity thereby processing the measured values through an algorithm and releasing the water accordingly which is an added feature of AISWP so that water can be efficiently used.

Drip and Surface Irrigation Water Use Efficiency of Tomato Crop Using Nuclear Techniques

International Nuclear Information System (INIS)

Mellouli, H.J.; Askri, H.; Mougou, R.

2003-01-01

Nations in the arid and semi-arid regions, especially the Arab countries, will have to take up an important challenge at the beginning of the 21 st century: increasing food production in order to realise food security for growing population, wile optimising the use of limited water resources. Using and adapting management techniques like the drip irrigation system could obtain the later. This would allow reduction in water losses by bare soil evaporation and deep percolation. Consequently improved water use efficiency could be realised. In this way, this work was conducted as a contribution on the Tunisian national programs on the optimisation of the water use. By mean a field study at Cherfech Experimental Station (30 km from Tunis), the effect of the irrigation system on the water use efficiency (WUE)-by a season tomato crop-was monitored by comparing three treatments receiving equivalent quantities of fertiliser: Fertigation, Drip irrigation and Furrow irrigation. Irrigation was scheduled by mean calculation of the water requirement based on the agro meteorological data, the plant physiological stage and the soil water characteristics (Clay Loam). The plant water consumption (ETR) was determined by using soil water balance method, where rainfall and amount of irrigation water readily measured

Yield and water use efficiency of irrigated soybean in Vojvodina, Serbia

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Pejić Borivoj

2012-01-01

Full Text Available Research was carried out at Rimski Šančevi experiment field of Institute of Field and Vegetable Crops in Novi Sad in the period 1993-2004. The experiment included an irrigated and non-irrigated control treatment. Irrigation water use efficiency (Iwue and evapotranspiration water use efficiency (ETwue were determined in order to assess the effectiveness of irrigation on soybean yield. The average yield increases of soybean due to irrigation practice was 0.82 t ha-1, ranging from 2.465 t ha-1 in years with limited precipitation and higher than average seasonal temperatures (2000 to 0 t ha-1 in rainy years (1996, 1997, 1999. Evapotranspiration water use efficiency (ETwue of soybean ranged from 0.11 kg m-3 to 1.36 kg m-3 with an average value of 0.66 kg m-3, while irrigation water use efficiency (Iwue varied from 0.11 kg m-3 to 1.04 kg m-3 with an average value of 0.56 kg m-3. Effect of irrigation on yield of soybean and results of both ETwue and Iwue which were similar to those obtained from the literature indicate that irrigation schedule of soybean in the study period was properly adapted to plant water requirements and water-physical soil properties. Determined values of ETwue and Iwue could be used for the planning, design and operation of irrigation systems, as well as for improving the production technology of soybean in the region.

Effects of different irrigation regimes on fruit production, oil quality, water use efficiency and agronomic nitrogen use efficiency of pumpkin

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Javad Hamzei

2016-05-01

Full Text Available Effect of different irrigation regimes and nitrogen fertilizer on percentage of grain fatty acids, yield, water and nitrogen use efficiency of pumpkin was studies as split plot based on complete randomized block design with three replications in growing season of 2013. Irrigation treatments (320, 420, 600 and 900 mm ha-1 were se as main plots and nitrogen fertilizer (0, 130, 260, 390 and 520 kg urea ha-1 were allocated in subplots. The effect of irrigation and nitrogen on all traits was significant. Also, interaction of irrigation × nitrogen had significant effect on all traits except WUE and NUE. The Highest values of linoleic fatty acid (33.99%, fruit yield (4.40 kg m-2, grain yield (1.53 kg m-2 and agronomic nitrogen use efficiency (32.27 kg fruit/kg urea were achieved at consumption of 600 mm water ha-1 and application of 390 kg urea ha-1. The highest water use efficiency for fruit and grain yield; 56.61 and 1.10 kg mm-1, were revealed at 600 mm irrigation water ha-1. Between nitrogen levels, maximum and minimum WUE for fruit and grain yield were achieved at 390 kg urea and non application of urea treatments, respectively. Also, maximum agronomic nitrogen efficiency belonged to 390 kg urea and minimum this trait with 33 reductions was revealed at 520 kg urea. Based on the results of this research and with considering of water and nitrogen use efficiency, irrigation of pumpkin plants with 600 mm water ha-1 and consumption of 390 kg urea ha-1 was identified as a suitable treatment.

Efficient Use of Water Resources in the Steel Industry

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Valentina Colla

2017-11-01

Full Text Available In the steel sector water management aims at improving the sustainability of the production cycle, resulting in resource efficiency benefits and in reduced water demand and costs. To be reused, water needs to be cooled and desalinized to avoid salt concentration in water circulation systems. The presented work includes two case studies carried out in an integrated steelmaking plant, respectively, to evaluate the possible implementation of ultrafiltration and reverse osmosis to reduce salt concentration in water streams and to investigate, through modelling and simulation, a process integration solution to improve water efficiency. Results showed that most salts are removed by reverse osmosis and that its coupling with ultrafiltration allows obtaining very high quality water; reuse of desalinated wastewater resulted in being more suitable and economically viable than its discharge. Moreover, modelling and simulation showed that the considered blowdown could be reused without significant changes in the receiving water network area. The industrial implementation of water recovery solutions can lead to a decrease of fresh water consumption, effluent discharge, and to improvement of product quality and equipment service life. The considered desalination technologies are transferable and easily implementable, and modelling and simulation are very useful in order to evaluate process modifications before real implementation.

Acid deposition and water use efficiency in Appalachian forests

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Malcomb, J.

2017-12-01

Multiple studies have reported increases in forest water use efficiency in recent decades, but the drivers of these trends remain uncertain. While acid deposition has profoundly altered the biogeochemistry of Appalachian forests in the past century, its impacts on forest water use efficiency have been largely overlooked. Plant ecophysiology literature suggests that plants up-regulate transpiration in response to soil nutrient limitation in order to maintain sufficient mass flow of nutrients. To test the impacts of acid deposition on forest eco-hydrology in central Appalachia, we integrated dendrochronological techniques, including tree ring δ13C analysis, with catchment water balance data from the Fernow Experimental Forest in West Virginia. Tree cores from four species were collected in Fernow Watershed 3, which has received experimental ammonium sulfate additions since 1989, and Watershed 7, an adjacent control catchment. Initial results suggest that acidification treatments have not significantly influenced tree productivity compared to a control watershed, but the effect varies by species, with tulip poplar showing greatest sensitivity to acidification. Climatic water balance, defined as the difference between growing season precipitation and evapotranspiration, is significantly related to annual tree ring growth, suggesting that climate may be driving tree growth trends in chronically acidified Appalachian forests. Tree ring 13C analysis from Fernow cores is underway and these data will be integrated with catchment hydrology data from five other sites in central Appalachia and the U.S. Northeast, representing a range of forest types, soil base saturations, and acid deposition histories. This work will advance understanding of how climate and acid deposition interact to influence forest productivity and water use efficiency, and improve our ability to model carbon and water cycling in forested ecosystems impacted by acid deposition.

A role for stomata in regulating water use efficiency in Populus x ...

African Journals Online (AJOL)

A role for stomata in regulating water use efficiency in Populus x euramericana and characterization of a related gene, PdERECTA. P Guo, X Xia, WL Yin. Abstract. The physiological mechanism of water use efficiency (WUE) remains elucidated, especially in poplar. We studied WUEi (instantaneous leaf transpiration ...

Policy Brief: Enhancing water-use efficiency of thermal power plants in India: need for mandatory water audits

Energy Technology Data Exchange (ETDEWEB)

Batra, R.K. (ed.)

2012-12-15

This policy brief discusses the challenges of water availability and opportunity to improve the water use efficiency in industries specially the thermal power plants. It presents TERI’s experience from comprehensive water audits conducted for thermal power plants in India. The findings indicate that there is a significant scope for saving water in the waste water discharge, cooling towers, ash handling systems, and the township water supply. Interventions like recycling wastewater, curbing leakages, increasing CoC (Cycles of concentration) in cooling towers, using dry ash handling etc., can significantly reduce the specific water consumption in power plants. However, the first step towards this is undertaking regular water audits. The policy brief highlights the need of mandatory water audits necessary to understand the current water use and losses as well as identify opportunities for water conservation, reduction in specific water consumption, and an overall improvement in water use efficiency in industries.

Response of gross ecosystem productivity, light use efficiency, and water use efficiency of Mongolian steppe to seasonal variations in soil moisture

Science.gov (United States)

Li, Sheng-Gong; Eugster, Werner; Asanuma, Jun; Kotani, Ayumi; Davaa, Gombo; Oyunbaatar, Dambaravjaa; Sugita, Michiaki

2008-03-01

The examination of vegetation productivity and use of light and water resources is important for understanding the carbon and water cycles in semiarid and arid environments. We made continuous measurements of carbon dioxide and water vapor fluxes over an arid steppe ecosystem in Mongolia by using the eddy covariance (EC) technique. These measurements allow an examination of EC-estimated gross ecosystem productivity (GEP), light use efficiency (LUE), and water use efficiency (WUE) of the steppe. Daily variations of GEP, LUE, and WUE were associated with daily variations of incident photosynthetically active radiation (PAR), ambient temperature (Ta), and vapor pressure deficit (VPD). The magnitudes of these variations were also dependent on canopy development. On the daily basis, GEP linearly correlated with evapotranspiration rate and PAR. LUE correlated positively with leaf area index, Ta, and soil moisture availability but negatively with the surface reflectivity for short-wave solar radiation. Throughout the growing season, both GEP and LUE responded strongly to precipitation-fed soil moisture in the top 20 cm of the soil. An examination of the responses of LUE and WUE to PAR under different soil moisture conditions shows that when soil water availability exceeded VPD, the steppe was most efficient in light use, whereas it was less efficient in water use. The multivariate analysis of variance also suggests that soil moisture availability, especially water status in the upper 20-cm soil layer with dense distribution of grass roots, is the most significant factor that governs GEP, WUE, and LUE. This study provides a preliminary assessment of the use of available water and light by the Mongolian arid steppe ecosystems under seasonally varying soil moisture conditions. A better understanding of these functional responses is required to predict how climate change may affect arid steppe ecosystems.

A preliminary investigation of the water use efficiency of sweet ...

African Journals Online (AJOL)

Fresh and dry aboveground biomass yield, stalk yield and stalk Brix % were measured at final harvest. Theoretical ethanol yield was calculated from fresh stalk yield and Brix %. Water use for the two growing seasons was 415 mm at Ukulinga and 398 mm at Hatfield. The ethanol water use efficiency (WUE) values for the ...

10 CFR 435.7 - Water used to achieve energy efficiency. [Reserved

Science.gov (United States)

2010-01-01

... 10 Energy 3 2010-01-01 2010-01-01 false Water used to achieve energy efficiency. [Reserved] 435.7 Section 435.7 Energy DEPARTMENT OF ENERGY ENERGY CONSERVATION ENERGY EFFICIENCY STANDARDS FOR NEW FEDERAL LOW-RISE RESIDENTIAL BUILDINGS Mandatory Energy Efficiency Standards for Federal Low-Rise Residential...

Climate and land use controls over terrestrial water use efficiency in monsoon Asia.

Science.gov (United States)

Hanqin Tian; Chaoqun Lu; Guangsheng Chen; Xiaofeng Xu; Mingliang Liu; et al

2011-01-01

Much concern has been raised regarding how and to what extent climate change and intensive human activities have altered water use efficiency (WUE, amount of carbon uptake per unit of water use) in monsoon Asia. By using a process-based ecosystem model [dynamic land ecosystem model (DLEM)], we examined effects of climate change, land use/cover change, and land...

Evapotranspiration and water use efficiency of different grass ...

African Journals Online (AJOL)

Evapotranspiration (Et) and water use efficiency (WUE) were determined for each of seven grass species during the 1986/87 seasons. The highest and lowest mean daily Et of 2, 39 and 1, 66 mm were recorded respectively for Themeda triandra and Sporobolus fimbriatus. Between species, the average Et for the two ...

Efficiency of lead removal from drinking water using cationic resin Purolite

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Ashour Mohammad Merganpour

2015-01-01

Full Text Available Background: Today, issues such as water shortage, difficulties and costs related to supplying safe water, and anomalous concentrations of heavy metals in groundwater and surface water resources, doubled the necessity of access to technical methods on removing these pollutants from water resources. Methods: In this lab study, cationic resin Purolite S-930 (with co-polymer styrene di-vinyl benzene structure was used for lead removal from drinking water containing up to 22 μg/L. Using statistical analysis and designing a full factorial experiment are the most important effective parameters on lead removal obtained through ion exchange process. Results: Analysis of response and interaction parameters of ion exchange showed that the resin column height has maximum and pH value has minimum effect on the efficiency of lead removal from aquatic environment. Trinary interaction of “effective size, flow rate, resin column high” has the most important for lead removal efficiency in this system. So the maximum efficiency was obtained at the mesh = 40, bed height =1.6 meter, and pH= 6.5. At the best operation conditions, ability to remove 95.42% of lead concentration can be achieved. Conclusion: Using the resin Purolite S-930 during 21-day service with 91.12% of mean lead removal ratio from drinking water is an economic and technical feasibility.

Energy efficiency improvement and fuel savings in water heaters using baffles

International Nuclear Information System (INIS)

Moeini Sedeh, Mahmoud; Khodadadi, J.M.

2013-01-01

Highlights: ► Thermal efficiency improved by simple/novel design of baffles inside water reservoir. ► Noticeable steady-state natural gas savings of about 5%. ► Extensive 3-D numerical investigations followed by experimental verifications. ► Baffle designs prototyped in identical water heaters for ANSI/US DOE test protocols. ► Numerical/experimental results verified thermal efficiency improvement and fuel savings. -- Abstract: Thermal efficiency improvement of a water heater was investigated numerically and experimentally in response to presence of a baffle, particularly designed for modifying the flow field within the water reservoir and enhancing heat transfer extracted into the water tank. A residential natural gas-fired water heater was selected for modifying its water tank through introducing a baffle for lowering natural gas consumption by 5% as a target. Based on the geometric features of the selected water heater, three-dimensional models of the water heater subsections were developed. Upon detailed studies of flow and heat transfer in each subsection, various sub-models were integrated to a complete model of the water heater. Thermal performance of the selected water heater was investigated numerically using computational fluid dynamics analysis. Prior to baffle design process and in order to verify the developed model of the water heater, time-dependent numerically-predicted temperatures were compared to the experimentally-measured temperatures under the same conditions at six (6) different locations inside the water tank and good agreement was observed. Upon verifying the numerical model, the fluid flow and heat transfer patterns were characterized for the selected water heater. The overall design of the baffle and its location and orientation were finalized based on the numerical results and a set of parametric studies. Finally, two baffle designs were proposed, with the second design being an optimized version of the first design. The

Water-use efficiency of a poplar plantation in Northern China

Science.gov (United States)

Jie Zhou; Zhiqiang Zhang; Ge sun; Xianrui Fang; Tonggang Zha; Jiquan Chen; Asko Noormets; Junting Guo; Steve McNulty

2014-01-01

The water-use efficiency (WUE) of an ecosystem—defined as the gross ecosystem production (GEP) divided by the evapotranspiration (ET)—is an important index for understanding the coupling of water and carbon and quantifying water–carbon trade-offs in forests. An open-path eddy covariance technique and a microclimate measurement system were deployed to investigate the...

Water Use Efficiency in Saline Soils under Cotton Cultivation in the Tarim River Basin

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Xiaoning Zhao

2015-06-01

Full Text Available The Tarim River Basin, the largest area of Chinese cotton production, is receiving increased attention because of serious environmental problems. At two experimental stations (Korla and Aksu, we studied the influence of salinity on cotton yield. Soil chemical and physical properties, soil water content, soil total suction and matric suction, cotton yield and water use efficiency under plastic mulched drip irrigation in different saline soils was measured during cotton growth season. The salinity (mS·cm−1 were 17–25 (low at Aksu and Korla, 29–50 (middle at Aksu and 52–62 (high at Aksu for ECe (Electrical conductivity measured in saturation-paste extract of soil over the 100 cm soil profile. The soil water characteristic curves in different saline soils showed that the soil water content (15%–23% at top 40 cm soil, lower total suction power (below 3500 kPa and lower matric suction (below 30 kPa in low saline soil at Korla had the highest water use efficiency (10 kg·ha−1·mm−1 and highest irrigation water use efficiency (12 kg·ha−1·mm−1 and highest yield (6.64 t·ha−1. Higher water content below 30 cm in high saline soil increased the salinity risk and led to lower yield (2.39 t·ha−1. Compared to low saline soils at Aksu, the low saline soil at Korla saved 110 mm irrigation and 103 mm total water to reach 1 t·ha−1 yield and increased water use efficiency by 5 kg·ha−1·mm−1 and 7 kg·ha−1·mm−1 for water use efficiency (WUE and irrigation water use efficiency (IWUE respectively.

Biomass production and water use efficiency of grassland in ...

African Journals Online (AJOL)

Using the results from a long-term grazing trial in the Dry Highland Sourveld of the KwaZulu-Natal province, we prepared a water use efficiency value (the ratio of the increment in annual biomass to total annual evapotranspiration) for this rangeland type. Using seasonal biomass measurements recorded between March ...

Characterizing Synergistic Water and Energy Efficiency at the Residential Scale Using a Cost Abatement Curve Approach

Science.gov (United States)

Stillwell, A. S.; Chini, C. M.; Schreiber, K. L.; Barker, Z. A.

2015-12-01

Energy and water are two increasingly correlated resources. Electricity generation at thermoelectric power plants requires cooling such that large water withdrawal and consumption rates are associated with electricity consumption. Drinking water and wastewater treatment require significant electricity inputs to clean, disinfect, and pump water. Due to this energy-water nexus, energy efficiency measures might be a cost-effective approach to reducing water use and water efficiency measures might support energy savings as well. This research characterizes the cost-effectiveness of different efficiency approaches in households by quantifying the direct and indirect water and energy savings that could be realized through efficiency measures, such as low-flow fixtures, energy and water efficient appliances, distributed generation, and solar water heating. Potential energy and water savings from these efficiency measures was analyzed in a product-lifetime adjusted economic model comparing efficiency measures to conventional counterparts. Results were displayed as cost abatement curves indicating the most economical measures to implement for a target reduction in water and/or energy consumption. These cost abatement curves are useful in supporting market innovation and investment in residential-scale efficiency.

Effect of water stress on total biomass, tuber yield, harvest index and water use efficiency in Jerusalem artichoke

Science.gov (United States)

The objectives of this study were to determine the effect of drought on tuber yield, total biomass, harvest index, water use efficiency of tuber yield (WUEt) and water use efficiency of biomass (WUEb), and to evaluate the differential responses of Jerusalem artichoke (JA) varieties under drought str...

Evaluation of the Yield and Water Use Efficiency of the Cucumber Inside Greenhouses

Directory of Open Access Journals (Sweden)

Ahmed Abied Hamza

2016-03-01

Full Text Available The need to provide fresh and good quality products during long periods throughout the year lead to the adoption of using greenhouses technology, so protected cropping has become a very popular production system in horticulture especially nowadays in Iraq. Evaluation the crop’s yield, water use efficiency and the irrigation system performance became essential. The main objectives of this research were to evaluate the yield index and the water use efficiency for the cucumber inside the greenhouses, and evaluate the performance of the drip irrigation efficiency inside the greenhouses. To accomplish these goals an experiment was conducted in the field located in AL-Mahawil Township in Babylon province .A set of measurements were recorded daily inside the greenhouses planting with cucumber for two consecutive seasons 2014 and 2015 related to weather parameters, crop evapotranspiration, drip system’s performance, and crop’s production. From the conducted field work inside the greenhouses and the analysis of the field data, the following conclusions were withdrawn: daily cucumber’s crop evapotranspiration was measured using the watermarks sensors, the total crop evapotranspiration for the seasons 2014 and 2015 were: 218.21mm and 281.86mm, respectively. The increasing in the crop evapotranspiration was due to change in weather parameters inside the greenhouses. The cucumber’s yield index for seasons 2014 and 2015 was: 8.87 and 8.53 kg/m2, respectively, which was close values between the two seasons. In this study, the yield index was high comparing with others approaches. The water use efficiency for the seasons 2014 and 2015 were: 23.23 and 18.22 kg/m3, respectively, which were low values comparing with other approaches. The reduction in the water use efficiency was due to the huge quantities of water applied through the seasons. Additionally, the irrigation efficiency for the drip system in this study for the seasons 2014 and 2015 were: 65

The importance of radiation for semiempirical water-use efficiency models

Science.gov (United States)

Boese, Sven; Jung, Martin; Carvalhais, Nuno; Reichstein, Markus

2017-06-01

Water-use efficiency (WUE) is a fundamental property for the coupling of carbon and water cycles in plants and ecosystems. Existing model formulations predicting this variable differ in the type of response of WUE to the atmospheric vapor pressure deficit of water (VPD). We tested a representative WUE model on the ecosystem scale at 110 eddy covariance sites of the FLUXNET initiative by predicting evapotranspiration (ET) based on gross primary productivity (GPP) and VPD. We found that introducing an intercept term in the formulation increases model performance considerably, indicating that an additional factor needs to be considered. We demonstrate that this intercept term varies seasonally and we subsequently associate it with radiation. Replacing the constant intercept term with a linear function of global radiation was found to further improve model predictions of ET. Our new semiempirical ecosystem WUE formulation indicates that, averaged over all sites, this radiation term accounts for up to half (39-47 %) of transpiration. These empirical findings challenge the current understanding of water-use efficiency on the ecosystem scale.

Biological and water-use efficiencies of sorghum-groundnut intercrop

African Journals Online (AJOL)

In order to compare water-use efficiency of sole crops and intercrops, 2 experiments were conducted in 2 consecutive years with sorghum (Sorghum bicolor L. Moench) and groundnut (Arachis hypogaea L.) on a loamy, Grossarenic Paleudult. In a randomized block, split-plot design, sorghum (SS), groundnut (GG), ...

Water conservation and improved production efficiency using closed-loop evaporative cooling systems

Energy Technology Data Exchange (ETDEWEB)

Marchetta, C. [Niagara Blower Co., Buffalo, NY (United States)

2009-07-01

This paper described wet surface air coolers (WSAC) that can be used in refineries and hydrocarbon processing plants to address water use issues. These closed-loop evaporative cooling systems are a cost-effective technology for both heat transfer and water conservation. WSACs can help deliver required cooling water temperatures and improve plant performance while using water streams currently considered to be unusable with conventional towers and heat exchangers. WSACs are versatile and can provide solutions to water use, water quality, and outlet temperature. The benefits of the WSAC include capital cost savings, reduced system pressures, lower carbon footprint, and the ability to use poor quality water as makeup. Water makeup can be blowdown from other equipment, plant effluent, reclaimed water, produced water, flue gas desulphurization (FGD) wastewater, and even seawater. Units can be manufactured with a wide variety of materials depending on water quality, water treatment, and cycles of concentration. This paper also provided comparisons to other alternative technologies, capital and operating cost savings, and site specific case studies. Two other system designs can accommodate closed-loop heat transfer applications, notably an open tower with a heat exchanger and a dry, air-cooled system. A WSAC system is an efficient and effective heat rejection technology for several reasons. The WSAC cooler or condenser utilizes latent cooling, which is far more efficient than sensible cooling. This means that a WSAC system can cool the same heat load with a smaller footprint than all-dry systems. 6 figs.

Water accounting implementation: water footprint and water efficiency of the coffee shop in Indonesia

Science.gov (United States)

Hendratno, S. P.; Agustine, Y.

2018-01-01

The purpose of this paper is for understand the water accounting practice in the company, especially beverage industry in Indonesia. The sample in this study is one coffee shop near Jakarta. Case study has been choosen as the method in this study. We collect data with semi-structured interview, observation, and survey about the water efficiency in the coffee shop. The operational officers such as barista, cashier, supervisor, and store manager are the respondents in this study. Operational management already understand about the importance of water efficiency in the coffee shop operation, but it can’t be implemented because their standard operation haven’t use the water efficiency as part of their procedures. The coffee shop’s operational standard in cleaning always takes much time and use so much water. The cleaning itself takes one until two hours each day only for cleaning bar and all operational equipment. This paper is for understand the water efficiency in the coffee shop with the focus is in their water footprint, operational standard that used every day in the coffee shop, and the connection between operational standard and the water efficiency.

Dominant clonal Eucalyptus grandis x urophylla trees use water more efficiently

Science.gov (United States)

Marina Shinkai Gentil Otto; Robert M. Hubbard; Dan Binkley; Jose Luis Stape

2014-01-01

Wood growth in trees depends on the acquisition of resources, and can vary with tree size leading to a variety of stand dynamics. Typically, larger trees obtain more resources and grow faster than smaller trees, but while light has been addressed more often, few case studies have investigated the contributions of water use and water use efficiency (WUE) within stands...

Genetic diversity of water use efficiency in Jerusalem artichoke (Helianthus tuberosus L.) germplasm

Science.gov (United States)

Genetic diversity in crop germplasm is an important resource for crop improvement, but information on genetic diversity is rare for Jerusalem artichoke, especially for traits related to water use efficiency. The objectives of this study were to investigate genetic variations for water use and water...

Incentives and technologies for improving irrigation water use efficiency

Science.gov (United States)

Bruggeman, Adriana; Djuma, Hakan; Giannakis, Elias; Eliades, Marinos

2014-05-01

The European Water Framework Directive requires Member States to set water prices that provide adequate incentives for users to use water resources efficiently. These new water pricing policies need to consider cost recovery of water services, including financial, environmental and resource cost. Prices were supposed to have been set by 2010. So far the record has been mixed. The European Commission has sent reasoned opinions to a number of countries (Austria, Belgium, Denmark, Estonia, Finland, Germany, Hungary, Netherlands, Sweden) requesting them to adjust their national legislation to include all water services. Unbalanced water pricing may negatively affect the agricultural sector, especially in the southern EU countries, which are more dependent on irrigation water for production. The European Commission is funding several projects that aim to reduce the burden of increasing water prices on farmers by developing innovative technologies and decision support systems that will save water and increase productivity. The FP7 ENORASIS project (grant 282949) has developed a new integrated irrigation management decision support platform, which include high-resolution, ensemble weather forecasting, a GIS widget for the location of fields and sensors and a comprehensive decision support and database management software package to optimize irrigation water management. The field component includes wireless, solar-powered soil moisture sensors, small weather stations, and remotely controlled irrigation valves. A mobile App and a web-package are providing user-friendly interfaces for farmers, water companies and environmental consultants. In Cyprus, agricultural water prices have been set to achieve a cost recovery rate of 54% (2010). The pricing policy takes in consideration the social importance and financial viability of the agricultural sector, an important flexibility provided by the Water Framework Directive. The new price was set at 0.24 euro per m3 for water supply

Irrigation management strategies to improve Water Use Efficiency of potatoes crop in Central Tunisia

Science.gov (United States)

Ghazouani, Hiba; Provenzano, Giuseppe; Rallo, Giovanni; Mguidiche, Amel; Douh, Boutheina; Boujelben, Abdelhamid

2015-04-01

In Tunisia, the expansion of irrigated area and the semiarid climate make it compulsory to adopt strategies of water management to increase water use efficiency. Subsurface drip irrigation (SDI), providing the application of high frequency small irrigation volumes below the soil surface have been increasingly used to enhance irrigation efficiency. At the same time, deficit irrigation (DI) has shown successful results with a large number of crop in various countries. However, for some crops like potatoes, DI is difficult to manage due to the rapid effect of water stress on tuber yield. Irrigation frequency is a key factor to schedule subsurface drip irrigation because, even maintaining the total seasonal volume, soil wetting patterns can result different during the growth period, with consequence on crop yield. Despite the need to enhance water use efficiency, only a few studies related to deficit irrigation of horticultural crops have been made in Tunisia. Objective of the paper was to assess the effects of different on-farm irrigation strategies on water use efficiency of potatoes crop irrigated with subsurface drip irrigation in a semiarid area of central Tunisia. After validation, Hydrus-2D model was used to simulate soil water status in the root zone, to evaluate actual crop evapotranspiration and then to estimate indirectly water use efficiency (IWUE), defined as the ratio between crop yield and total amount of water supplied with irrigation. Field experiments, were carried out in Central Tunisia (10° 33' 47.0" E, 35° 58' 8.1° N, 19 m a.s.l) on a potatoes crop planted in a sandy loam soil, during the growing season 2014, from January 15 (plantation of tubers) to May 6 (harvesting). Soil water status was monitored in two plots (T1 and T2) maintained under the same management, but different irrigation volumes, provided by a SDI system. In particular, irrigation was scheduled according to the average water content measured in the root zone, with a total of 8

Dry matter production, seed yield and water use efficiency of some grain legumes grown under different water regimes using nuclear technique

International Nuclear Information System (INIS)

Harb, O.M.S.; Salem, M.S.A.; Abdalla, A.A.; Abd-Elwahed, N.M.

2007-01-01

Two field experiments were performed in the experimental farm at the Atomic Energy Authority, Inshas, Egypt, during 2002 and 2004 growing seasons to evaluate the responses of dry matter production, seed yield, water use efficiency and root characteristics for three legumes species, i.e. soybean (Glycine max cv. clark), cowpea (Vigna unguiculata cv. Kafr El-Sheikh) and mungbean (Vigna radiate cv. kawmy 1) grown on a new reclaimed sandy soil under different water regimes. The experiments were laid out using a single line source sprinkler irrigation system which allows a gradual variation of irrigation water, i.e. full irrigation (W1), medium water stress (W2) and severe water stress (W3). The obtained results indicated that normal irrigation (W1) gave the highest above ground dry matter production at flowering stage and total dry matter yield at maturity for the tested legumes. Water stress decreased significantly seed yields for all the tested legume seeds. The seed yield of normal watering condition treatment (W1) out yielded seed yield of those irrigated with medium water stress (W2) and severe water stress (W3). Mungbean and cowpea were more adapted to severe water stress than soybean. Most of the reduction in yield arose from a decrease in pod number. Pod number, number of seeds per pod and the thousand seed weight were significantly affected by water stress. The highest water use efficiency based on seed yield or dry matter yield were obtained by exposing the legume plants to medium water stress (W2), while the lowest value was obtained by exposing the plants to severe water stress (W3). There were significant differences in WUE among the tested species, whereas, mungbean showed the highest value in response to water stress, followed by soybean while cowpea showed the lowest value of water use efficiency. Rooting depth was increased under the severe water stress treatment as compared with well watered condition in the tested legume plants. Mungbean had the

Strategies for improving water use efficiency of livestock production in rain-fed systems.

Science.gov (United States)

Kebebe, E G; Oosting, S J; Haileslassie, A; Duncan, A J; de Boer, I J M

2015-05-01

Livestock production is a major consumer of fresh water, and the influence of livestock production on global fresh water resources is increasing because of the growing demand for livestock products. Increasing water use efficiency of livestock production, therefore, can contribute to the overall water use efficiency of agriculture. Previous studies have reported significant variation in livestock water productivity (LWP) within and among farming systems. Underlying causes of this variation in LWP require further investigation. The objective of this paper was to identify the factors that explain the variation in LWP within and among farming systems in Ethiopia. We quantified LWP for various farms in mixed-crop livestock systems and explored the effect of household demographic characteristics and farm assets on LWP using ANOVA and multilevel mixed-effect linear regression. We focused on water used to cultivate feeds on privately owned agricultural lands. There was a difference in LWP among farming systems and wealth categories. Better-off households followed by medium households had the highest LWP, whereas poor households had the lowest LWP. The variation in LWP among wealth categories could be explained by the differences in the ownership of livestock and availability of family labor. Regression results showed that the age of the household head, the size of the livestock holding and availability of family labor affected LWP positively. The results suggest that water use efficiency could be improved by alleviating resource constraints such as access to farm labor and livestock assets, oxen in particular.

Water Use Efficiency Improvement against a Backdrop of Expanding City Agglomeration in Developing Countries—A Case Study on Industrial and Agricultural Water Use in the Bohai Bay Region of China

Directory of Open Access Journals (Sweden)

Minghao Bai

2017-02-01

Full Text Available Most city agglomerations of developing countries face water shortages and pollution due to population growth and industrial aggregation. To meet such water security challenges, policy makers need to evaluate water use efficiency at the regional or basin level because the prosperity of city agglomerations is indispensable to the sustainable development of the region or basin. To solve the issue, this paper adopts a non-directional distance function within the framework of environmental production technology to measure water use efficiency. Based on the distance between actual water use efficiency and the ideal efficiency, it calculates the potential reduction space of water input and pollutants by slack adjustment. Added to the Malmquist index, it forms a non-radial Malmquist water use performance index, which can be divided into technological change and technical efficiency change, to measure dynamic water use efficiency. Further, water use efficiency change is analyzed from the perspectives of technological improvement and institutional construction. Bohai Bay city agglomeration, a typical water-deficient city agglomeration in China, is taken as a case study, and data on water resource, environment, and economy from 2011 to 2014 have been used. In conclusion, there is much space for water use efficiency improvement on the whole. However, even having considered potential reduction space of water input and pollutant discharge under current environmental production technology, it is still not enough to support the city agglomeration’s sustainable development. To relieve current potential water safety hazards, not only technical improvement but also institution innovation for highly efficient water use should be kept accelerating in Bohai Bay region. In terms of urban water management in developing countries, the research conclusion is of theoretical and practical significance.

Improving the water use efficiency of olive trees growing in water harvesting systems

Science.gov (United States)

Berliner, Pedro; Leake, Salomon; Carmi, Gennady; Agam, Nurit

2017-04-01

Water is a primary limiting factor for agricultural development in many arid and semi-arid regions in which a runoff generation is a rather frequent event. If conveyed to dyke surrounded plots and ponded, runoff water can thereafter be used for tree production. One of the most promising runoff collection configurations is that of micro-catchments in which water is collected close to the area in which runoff was generated and stored in adjacent shallow pits. The objective of this work was to assess the effect of the geometry of runoff water collection area (shallow pit or trench) on direct evaporative water losses and on the water use efficiency of olive trees grown in them. The study was conducted during the summer of 2013 and 2014. In this study regular micro-catchments with basins of 9 m2 (3 x 3 m) by 0.1 m deep were compared with trenches of one meter deep and one meter wide. Each configuration was replicated three times. One tree was planted in each shallow basin and the distance between trees in the 12 m long trench was four meters. Access tubes for neutron probes were installed in the micro-catchments and trenches (four and seven, respectively) to depths of 2.5 m. Soil water content in the soil profile was monitored periodically throughout drying periods in between simulated runoff events. Transpiration of the trees was estimated from half-hourly sap flow measurements using a Granier system. Total transpiration fluxes were computed for time intervals corresponding to consecutive soil water measurements. During the first year, a large runoff event was simulated by applying once four cubic meters to each plot; and in the second year the same volume of water was split into four applications, simulating a series of small runoff events. In both geometries, trees received the same amount of water per tree. Evaporation from trenches and micro-catchments was estimated as the difference between evapotranspiration obtained computing the differences in total soil water

Experimental analysis to improving thermosyphon (TPCT) thermal efficiency using nanoparticles/based fluids (water)

Science.gov (United States)

Hoseinzadeh, S.; Sahebi, S. A. R.; Ghasemiasl, R.; Majidian, A. R.

2017-05-01

In the present study an experimental set-up is used to investigate the effect of a nanofluid as a working fluid to increase thermosyphon efficiency. Nanofluids are a new form of heat transfer media prepared by suspending metallic and nonmetallic nanoparticles in a base fluid. The nanoparticles added to the fluid enhance the thermal characteristics of the base fluid. The nanofluid used in this experiment was a mixture of water and nanoparticles prepared with 0.5%, 1%, 1.5%, or 2% (v) concentration of silicon carbide (SiC) nanoparticles and 1%, 2% and 3% (v) concentration of aluminum oxide (Al2O3) in an ultrasonic homogenizer. The results indicate that the SiC/water and Al2O3/water nanofluids increase the thermosyphon performance. The efficiency of the thermosyphon using the 2% (v) (SiC) nanoparticles nanofluid was 1.11 times that of pure water and the highest efficiency occurs for the 3% (Al2O3) nanoparticle concentration with input power of 300 W. The decrease in the temperature difference between the condenser and evaporator confirms these enhancements.

Analysis of China department water consumption efficiency

Science.gov (United States)

Li, Wei; Wang, Xi-Feng; Liu, Jia-Hong

2018-03-01

The water comparable non-competitive input-out model of China in 2002, 2007 and 2012 is established to calculate the department water consumption efficiency. The water direct and complete consumption coefficients of 38 departments are analysed. Agriculture and Electricity and steam supply have the highest water consumption coefficients and utilize water resource mainly by the direct way. Manufacture of food products and tobacco products, Manufacture of textiles, Manufacture of wearing apparel and leather products and Information service activities have high water complete consumption coefficients and affect water consumption mainly by the indirect way. Water complete consumption efficiency measures the efficiency from the view of final product, which reflected the department water use driving force more precisely.

Automation of irrigation systems to control irrigation applications and crop water use efficiency

Science.gov (United States)

Agricultural irrigation management to slow water withdrawals from non-replenishing quality water resources is a global endeavor and vital to sustaining irrigated agriculture and dependent rural economies. Research in site-specific irrigation management has shown that water use efficiency, and crop p...

A hairy-leaf gene, BLANKET LEAF, of wild Oryza nivara increases photosynthetic water use efficiency in rice.

Science.gov (United States)

Hamaoka, Norimitsu; Yasui, Hideshi; Yamagata, Yoshiyuki; Inoue, Yoko; Furuya, Naruto; Araki, Takuya; Ueno, Osamu; Yoshimura, Atsushi

2017-12-01

High water use efficiency is essential to water-saving cropping. Morphological traits that affect photosynthetic water use efficiency are not well known. We examined whether leaf hairiness improves photosynthetic water use efficiency in rice. A chromosome segment introgression line (IL-hairy) of wild Oryza nivara (Acc. IRGC105715) with the genetic background of Oryza sativa cultivar 'IR24' had high leaf pubescence (hair). The leaf hairs developed along small vascular bundles. Linkage analysis in BC 5 F 2 and F 3 populations showed that the trait was governed by a single gene, designated BLANKET LEAF (BKL), on chromosome 6. IL-hairy plants had a warmer leaf surface in sunlight, probably due to increased boundary layer resistance. They had a lower transpiration rate under moderate and high light intensities, resulting in higher photosynthetic water use efficiency. Introgression of BKL on chromosome 6 from O. nivara improved photosynthetic water use efficiency in the genetic background of IR24.

Hydrological cycle and water use efficiency of veld in different ...

African Journals Online (AJOL)

Hydraulic non-floating lysimeters were used to determine the evapotranspiration (Et) and water use efficiency (W.U.E.) of veld in different successional stages for the period September 1978 to June 1979. In addition runoff of the various successional stages was recorded on runoff plots.Averages of 1,018 litres, 1,258 litres ...

Efficiency of water use in sugar beet and processing tomato cropped in Southern Italy

Directory of Open Access Journals (Sweden)

Alessandro Vittorio Vonella

2011-02-01

Full Text Available A more efficient crop water use in biomass and yield accumulation can represent great water saving in the waterlimited environments. Crop management – irrigation, sowing time, fertilization – could affect water (and irrigation water transformation efficiency in dry matter and commercial yield of beet and tomato in Southern Italy. This field research, carried out in two locations of Southern Italy (Foggia and Vasto in 1998-2002 period, compared for sugar beet irrigation regimes (optimal, 100% of ETc and reduced, 60% of ETc and sowing times (autumnal and spring; for tomato three irrigation regimes were compared, re-establishing 100% (ET100, 66 (ET66 and 33% (ET33 of crop evapotranspiration. Water and irrigation water transformation efficiency in harvestable yield (WUEhdm and IRRWUE hdm, in total dry matter (WUEdm and IRRWUEdm and sucrose (WUEsuc were calculated both at harvest and during crop cycle. The results showed a significant effect of sowing date on WUEhdm and WUEsuc of sugar beet (respectively 2.44 and 2.12 for autumnal sowing and 1.08 and 0.84 kg m-3 for spring sowing. Irrigation regimes did not show significant differences. “Irrigation x sowing times” interaction was significant for WUEdm, with a superiority of reduced vs. optimal only in spring sowing time. In tomato, WUEdm was not affected by the irrigation regime, while WUEhdm in ET66 treatment was more efficient treatment than ET100 (1.19 vs. 1.00 kg m-3. “Year” effect was significant for WUEdm and WUEhdm with lowest values in the driest year. IRRWUE was higher in tomato than in sugar beet, considering dry matter, fresh harvestable product and also from an economic point of view. The temporal analysis of water use efficiency showed WUEdm and WUEhdm greater in the middle of crop cycle in autumnal than in spring sugar beet, but not between the irrigation regimes. In tomato, the ET66 treatment resulted the most efficient in water using, especially at the end of crop cycle

Efficiency of water use in sugar beet and processing tomato cropped in Southern Italy

Directory of Open Access Journals (Sweden)

Michele Rinaldi

2006-09-01

Full Text Available A more efficient crop water use in biomass and yield accumulation can represent great water saving in the waterlimited environments. Crop management – irrigation, sowing time, fertilization – could affect water (and irrigation water transformation efficiency in dry matter and commercial yield of beet and tomato in Southern Italy. This field research, carried out in two locations of Southern Italy (Foggia and Vasto in 1998-2002 period, compared for sugar beet irrigation regimes (optimal, 100% of ETc and reduced, 60% of ETc and sowing times (autumnal and spring; for tomato three irrigation regimes were compared, re-establishing 100% (ET100, 66 (ET66 and 33% (ET33 of crop evapotranspiration. Water and irrigation water transformation efficiency in harvestable yield (WUEhdm and IRRWUE hdm, in total dry matter (WUEdm and IRRWUEdm and sucrose (WUEsuc were calculated both at harvest and during crop cycle. The results showed a significant effect of sowing date on WUEhdm and WUEsuc of sugar beet (respectively 2.44 and 2.12 for autumnal sowing and 1.08 and 0.84 kg m-3 for spring sowing. Irrigation regimes did not show significant differences. “Irrigation x sowing times” interaction was significant for WUEdm, with a superiority of reduced vs. optimal only in spring sowing time. In tomato, WUEdm was not affected by the irrigation regime, while WUEhdm in ET66 treatment was more efficient treatment than ET100 (1.19 vs. 1.00 kg m-3. “Year” effect was significant for WUEdm and WUEhdm with lowest values in the driest year. IRRWUE was higher in tomato than in sugar beet, considering dry matter, fresh harvestable product and also from an economic point of view. The temporal analysis of water use efficiency showed WUEdm and WUEhdm greater in the middle of crop cycle in autumnal than in spring sugar beet, but not between the irrigation regimes. In tomato, the ET66 treatment resulted the most efficient in water using, especially at the end of crop cycle

Cassava productivity linked to potassium's influence on water use efficiency

NARCIS (Netherlands)

Ezui, K.S.; Franke, A.C.; Leffelaar, P.A.; Giller, K.E.

2017-01-01

This paper presents the results of field studies conducted in Togo (Djakakope and Sevekpota) to assess the effect of potassium (K) on cassava yield, water use efficiency (WUE) and transpiration as affected by nitrogen (N) and phosphorus (P) availability under rainfed conditions. It was shown that an

Nitrogen uptake and fertilizer nitrogen use efficiency of wheat under different soil water conditions

International Nuclear Information System (INIS)

Wang Baiqun; Zhang Wei; Yu Cunzu

1999-01-01

The pot experiment was conducted to study the effects of soil water regime and fertilizer nitrogen rate on the yields, nitrogen uptake and fertilizer nitrogen utilization of wheat by using 15 N tracer method. The results showed that the aboveground biomass, stem yield and grain yield increased with the increase of soil moisture in the fertilizer nitrogen treatments. All the yield increased with the increase of the fertilizer nitrogen rate in the soil water treatments. It was found that both soil water regime and fertilizer nitrogen rate significantly influenced the amount of nitrogen uptake by wheat according to the variance analysis. The amount of nitrogen uptake increased with the rise of the soil moisture in fertilizer nitrogen treatments and the amount also increased with the increase of the urea nitrogen rate in the soil water regime. Soil water regimes not only had an impact on nitrogen uptake but also had a close relationship with soil nitrogen supply and fertilizer nitrogen use efficiency. The soil A values decreased in urea treatment and increased with the rise of the soil moisture in the combination treatment of urea with pig manure. The fertilizer nitrogen use efficiency rose with the rise of the soil moisture in the same fertilizer nitrogen treatment. The fertilizer nitrogen use efficiency of the urea treatment was 13.3%, 27.9% and 32.3% in the soils with 50%, 70% and 90% of the field water capacity, respectively. The fertilizer nitrogen use efficiency in the combination treatment of urea with pig manure was 20.0%, 29.9% and 34.4% in the soils of above three levels, respectively. It was concluded that the low soil moisture restricted urea nitrogen use efficiency (UNUE) and the UNUE could be raised by combination treatment of urea with manure in the soil of enough moisture

[Effects of strip planting and fallow rotation on the soil and water loss and water use efficiency of slope farmland].

Science.gov (United States)

Hou, Xian-Qing; Li, Rong; Han, Qing-Fang; Jia, Zhi-Kuan; Wang, Wei; Yan, Bo; Yang, Bao-Ping

2012-08-01

In order to enhance the soil water-retaining capacity of slope farmland and reduce its soil and water loss, a field study was conducted in 2007-2010 to examine the effects of strip planting and fallow rotation on the soil water regime, soil and water loss characteristics, and water use efficiency of a 10 degrees-15 degrees slope farmland in the arid area of southern Ningxia, Northwest China. Compared with the traditional no-strip planting, strip planting and fallow rotation increased the soil water content in 0-200 cm layer significantly, with an increment of 4.9% -7.0%. Strip planting and fallow rotation pattern could also effectively conserve the soil water in rain season, and obviously improve the soil water regime at crops early growth stages. As compared to no-strip planting, strip planting and fallow rotation increased the soil water content in 0-200 cm layer by 5.4%-8.5%, decreased the surface runoff by 0.7-3.2 m3 x hm(-2), sediment runoff by 0.2-1.9 t x hm(-2), and soil total N loss by 42.1% -73.3%, while improved the crop water use efficiency by 6.1% -24.9% and the precipitation use efficiency by 6.3% -15.3%.

Water Use Efficiency and Its Influencing Factors in China: Based on the Data Envelopment Analysis (DEA—Tobit Model

Directory of Open Access Journals (Sweden)

Shuqiao Wang

2018-06-01

Full Text Available Water resources are important and irreplaceable natural and economic resources. Achieving a balance between economic prosperity and protection of water resource environments is a major issue in China. This article develops a data envelopment analysis (DEA approach with undesirable outputs by using Seiford’s linear converting method to estimate water use efficiencies for 30 provinces in China, from 2008–2016,and then analyzes the influencing factors while using a DEA-Tobit model. The findings show that the overall water use efficiency of the measured Chinese provinces, when considering sewage emissions as the undesirable output, is 0.582. Thus, most regions still need improvement. Provinces with the highest water efficiency are located in economically developed Eastern China. The spatial pattern of water use efficiency in China is consistent with the general pattern of regional economic development. This study implies that factors like export dependence, technical progress, and educational value have a positive influence on water use efficiency. Further, while industrial structure has had a negative impact, government intervention has had little impact on water use efficiency. These research results will provide a scientific basis for the government to make plans for water resource development, and it may be helpful in improving regional sustainable development.

The 13C isotope discrimination technique for identifying durum wheat cultivars efficient in uptake and use of water

International Nuclear Information System (INIS)

Mechergui, M.; Snane, M.H.

1996-01-01

The water balance model using a neutron moisture probe and the 13 C isotope discrimination method were used in this field to rank durum wheat genotypes for water use efficiency. The results presented focus on the first two years of a five-year study. Eighteen durum wheat cultivars were used in the first experiment. The 13 C/ 12 C ratio was measured to examine the correlation between this ratio and the water use efficiency. Total water consumption was calculated and the grain and straw yields and other parameters were also recorded. The results show differences between cultivars with respect to water use efficiency, 13 C discrimination and grain yield. From this experiment, four cultivars were selected for a detailed study in the second year. The data from this study show that there is a positive correlation between grain water use efficiency and Δ. Thus, it may be possible to use Δ as a tool for screening out water use efficient cultivars in semi-arid regions. (author). 12 refs, 5 figs, 1 tab

Water use efficiency of coriander produced in a low-cost hydroponic system

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José A. Santos Júnior

2015-12-01

Full Text Available ABSTRACT The increase of water use efficiency in crop production is a clear need in areas with restricted access to this resource and, in these cases, the adoption of forms of cultivation contextualized to local conditions are essential. Thus, the implications of the variation in the amount of seeds per cell (0.5, 1.0, 1.5 and 2.0 g and spacing between cells (7.0, 10.0 and 15.0 cm on variables related to consumption and water use efficiency for the production of coriander (cv. Tabocas in a low-cost hydroponic system, an alternative for semiarid regions, were evaluated. A completely randomized experimental design, analysed in 4 x 3 factorial scheme with three replicates, was adopted, and the data were subjected to analysis of variance at 0.05 probability level. It was found that the reduction in the spacing between cells has a better cost-benefit ratio with respect to water consumption, biomass produced and cost of seeds. Therefore, it is recommended the adoption of a spacing of 7.0 cm between cells and the use of 1.0 g seeds per cell; this configuration promoted efficiency of 81.59 g L-1 in shoot green mass production and total mass of 62.4 g coriander bunches.

THE EFFICIENCY OF ELECTROCOAGULATION PROCESS USING ALUMINUM ELECTRODES IN REMOVAL OF HARDNESS FROM WATER

Directory of Open Access Journals (Sweden)

M. Malakootian ، N. Yousefi

2009-04-01

Full Text Available There are various techniques for removal of water hardness each with its own special advantages and disadvantages. Electrochemical or electrocoagulation method due to its simplicity has gained a great attention and is used for removal of various ions and organic matters. The aim of the present study was to investigate the efficiency of this technique in removal of water hardness under different conditions. This experimental study was performed using a pilot plant. The applied pilot was comprised of a reservoir containing aluminum sheet electrodes. The electrodes were connected as monopolar and a power supply was used for supplying direct electrical current. Drinking water of Kerman (southeast of Iran was used in the experiments. The efficiency of the system in three different pH, voltages and time intervals were determined. Results showed the efficiency of 95.6% for electrocoagulation technique in hardness removal. pH and electrical potential had direct effect on hardness removal in a way that the highest efficiency rate was obtained in pH=10.1, potential difference of 20 volt and detention time of 60 minutes. Considering the obtained efficiency in the present study, electrocoagulation technique may be suggested as an effective alternative technique in hardness removal.

China’s Water Utilization Efficiency: An Analysis with Environmental Considerations

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Hailiang Ma

2016-05-01

Full Text Available This paper estimates China’s water utilization efficiency using the directional distance function to take into account the environmental degradation affecting the economy. We further analyze the spatial correlation and the factors influencing the utilization efficiency using spatial panel data models. The results show that water utilization efficiency in China differs between provinces and regions. For example, water utilization efficiency in the eastern coastal provinces is significantly higher than that of inland provinces. The pattern of spatial auto-correlation Moran’s I index presents significant spatial auto-correlation and evident cluster tendencies in China’s inter-provincial water utilization. Factors that contribute to water utilization efficiency include economic development, technological progress, and economic openness. Negative factors affecting water utilization efficiency arise from industrial structure, government interference, and water resources endowment. In addition, the price of water resources is insignificant. The improvement of water utilization efficiency is essential to sustainable economic development. To raise the utilization efficiency of water resources, China should focus on transforming its industrial restructure, advancing technological development, enhancing economic openness, and encouraging entrepreneurial innovations. Moreover, establishing a mechanism to encourage water conservation and reduce wastewater pollution will further increase water utilization efficiency.

Studies on 13C isotope discrimination for identifying tree provenances efficient in water use under water deficit conditions in Kenya

International Nuclear Information System (INIS)

Nyamai, D.O.; Juma, P.O.

1996-01-01

Screening for drought resistance traits was conducted in a semi-arid site in Machakos using 11 provenances of Acacia tortilis, 6 provenances of Prosopis juliflora and 4 provenances of Casuarina equisetifolia. Tolerance to drought was assessed by the 13 C isotope discrimination (Δ) technique as well as by determining the waster use efficiency (WUE). Measurements of dry matter and early growth performance were also taken as indicators of drought resistance. The results showed significant differences in the 13 C Isotope discrimination, water use efficiency and dry matter yields by the different provenances tested. Generally, the results indicated that there were significant linear negative relationships between 13 C discrimination with water use efficiency as well as dry matter yield. The results further showed highly significant positive relationship between dry matter yield and water use efficiency. Acacia tortilis provenances from middle East and neighbouring North Eastern Africa region appear to possess the greatest abilities for drought resistance in comparison with those from sub-saharan Africa as indicated by their 13 C Isotope discrimination levels, dry matter yield and water use efficiency. However, Acacia provenance from Israel had the highest drought resistance trail. Prosopis provenance from Costa Rica and Casuarina from Dakar region in Senegal also emerged as the best provenances in terms of drought tolerance as shown by the 13 C isotope discrimination and dry matter traits. (author). 8 refs, 4 figs, 3 tabs

Strategies for improving water use efficiency in livestock feed production in rain-fed systems

NARCIS (Netherlands)

Kebebe, E.G.; Oosting, S.J.; Haileslassie, A.; Duncan, A.J.; Boer, de I.J.M.

2015-01-01

Livestock production is a major consumer of fresh water, and the influence of livestock production on global fresh water resources is increasing because of the growing demand for livestock products. Increasing water use efficiency of livestock production, therefore, can contribute to the overall

Water Use Efficiency and Water Deficit Tolerance Indices in Terminal Growth Stages in Promising Bread Wheat genotypes

Directory of Open Access Journals (Sweden)

M. Nazeri

2016-02-01

Full Text Available Introduction During growth stages of wheat, anthesis and grain filling periods are the most susceptible to drought. Wheat cultivars that are more tolerant to terminal drought are more suitable to Mediterranean conditions. To increase water use efficiency, the target environment should be taken into account, because one trait might be effective in an environment but ineffective in another environment. In general, some traits like early vigour and root absorbtion capacity are so important in water deficient conditions. In recent years, increasing grain yield was due to increasing grain numbers. Although both the source and sink is considered as the limitation factors in increasing grain yield in old cultivars, even in the new cultivars sink seems to be more important. In fact, phenological adjustment adapted with seasonal precipitation pattern can improve water use efficiency in drought conditions. Suitable flowering time is the most important trait that is correlated with increasing water use efficiency in drought conditions. Materials and Methods In order to evaluate the level of drought tolerance in promising bread wheat lines, a split plot arrangements using randomized complete block design with three replications was carried out in 2008-09 and 2009-10 growing seasons at Torogh Agricultural Research Field Station, Mashhad. in. water limited conditions at three levels Optimum moisture conditions (L1, removal irrigation and using rain shelter from milky grain stage to maturity (L2, removal irrigation and using rainshelter from anthesis to maturity (L3 were assigned to main plots. Ten bread wheat lines include suitable for cold and dry regions (V1: (Toos, V2: (C-81-10, V3: (pishgam, V4: (C-84-4, V5: (C-84-8, V6: (C-D-85-15, V7: (C-D-85-9, V8: (C-D-84-5502, V9: (C-D-85-5502 and V10: (C-85-6 were randomized in sub-plots. Stress susceptibility index (SSI, stress tolerance index (STI and tolerance (TOL were calculated using following equations: D = 1

Chromosomal location of traits associated with wheat seedling water and phosphorus use efficiency under different water and phosphorus stresses.

Science.gov (United States)

Cao, Hong-Xing; Zhang, Zheng-Bin; Sun, Cheng-Xu; Shao, Hong-Bo; Song, Wei-Yi; Xu, Ping

2009-09-18

The objective of this study was to locate chromosomes for improving water and phosphorus-deficiency tolerance of wheat at the seedling stage. A set of Chinese Spring-Egyptian Red wheat substitution lines and their parent Chinese Spring (recipient) and Egyptian Red (donor) cultivars were measured to determine the chromosomal locations of genes controlling water use efficiency (WUE) and phosphorus use efficiency (PUE) under different water and phosphorus conditions. The results underlined that chromosomes 1A, 7A, 7B, and 3A showed higher leaf water use efficiency (WUE(l) = Pn/Tr; Pn = photosynthetic rate; Tr = transpiration rate) under W-P (Hoagland solution with 1/2P), -W-P (Hoagland solution with 1/2P and 10% PEG). Chromosomes 7A, 3D, 2B, 3B, and 4B may carry genes for positive effects on individual plant water use efficiency (WUE(p) = biomass/TWC; TWC = total water consumption) under WP (Hoagland solution), W-P and -W-P treatment. Chromosomes 7A and 7D carry genes for PUE enhancement under WP, -WP (Hoagland solution with 10% PEG) and W-P treatment. Chromosome 7A possibly has genes for controlling WUE and PUE simultaneously, which indicates that WUE and PUE may share the same genetic background. Phenotypic and genetic analysis of the investigated traits showed that photosynthetic rate (Pn) and transpiration rate (Tr), Tr and WUE(l) showed significant positive and negative correlations under WP, W-P, -WP and -W-P, W-P, -WP treatments, respectively. Dry mass (DM), WUE(P), PUT (phosphorus uptake) all showed significant positive correlation under WP, W-P and -WP treatment. PUE and phosphorus uptake (PUT = P uptake per plant) showed significant negative correlation under the four treatments. The results might provide useful information for improving WUE and PUE in wheat genetics.

Chromosomal Location of Traits Associated with Wheat Seedling Water and Phosphorus Use Efficiency under Different Water and Phosphorus Stresses

Directory of Open Access Journals (Sweden)

Wei-Yi Song

2009-09-01

Full Text Available The objective of this study was to locate chromosomes for improving water and phosphorus-deficiency tolerance of wheat at the seedling stage. A set of Chinese Spring- Egyptian Red wheat substitution lines and their parent Chinese Spring (recipient and Egyptian Red (donor cultivars were measured to determine the chromosomal locations of genes controlling water use efficiency (WUE and phosphorus use efficiency (PUE under different water and phosphorus conditions. The results underlined that chromosomes 1A, 7A, 7B, and 3A showed higher leaf water use efficiency (WUEl = Pn/Tr; Pn = photosynthetic rate; Tr = transpiration rate under W-P (Hoagland solution with1/2P, -W-P (Hoagland solution with 1/2P and 10% PEG. Chromosomes 7A, 3D, 2B, 3B, and 4B may carry genes for positive effects on individual plant water use efficiency (WUEp = biomass/TWC; TWC = total water consumption under WP (Hoagland solution, W-P and -W-P treatment. Chromosomes 7A and 7D carry genes for PUE enhancement under WP, -WP (Hoagland solution with 10% PEG and W-P treatment. Chromosome 7A possibly has genes for controlling WUE and PUE simultaneously, which indicates that WUE and PUE may share the same genetic background. Phenotypic and genetic analysis of the investigated traits showed that photosynthetic rate (Pn and transpiration rate (Tr, Tr and WUEl showed significant positive and negative correlations under WP, W-P, -WP and -W-P, W-P, -WP treatments, respectively. Dry mass (DM, WUEP, PUT (phosphorus uptake all showed significant positive correlation under WP, W-P and -WP treatment. PUE and phosphorus uptake (PUT = P uptake per plant showed significant negative correlation under the four treatments. The results might provide useful information for improving WUE and PUE in wheat genetics.

Removing efficiency of radon from water by different methods

International Nuclear Information System (INIS)

Muellerova, M.; Holy, K.; Gulasova, Z.; Polaskova, A.

2008-01-01

In this contribution problem of radon removing from water samples by different methods was tested. Lowest efficiency of deemanation was achieved at tossing of water from one vessel into the other. For increasing of efficiency deemanation of radon use of needle-bath principle was also used. Low efficiency deemanation was found at trapping of radon from sample of water by toluene (83 ± 5) %, too. Reversal highest efficiency deemanation of radon from water was reached at aerating by argon (95 ± 6)%. It is shown, that reduction of volume activity of radon in water under 0.1 Bq/dm l - 3 is big problem. Suppression of this limit will claim use of more completion and sophistic approaches. (author)

Efficient Overall Water-Splitting Electrocatalysis Using Lepidocrocite VOOH Hollow Nanospheres

KAUST Repository

Shi, Huanhuan

2016-11-29

Herein we report the control synthesis of lepidocrocite VOOH hollow nanospheres and further their applications in electrocatalytic water splitting for the first time. By tuning the surface area of the nanospheres, the optimal performance can be achieved with low overpotentials of 270 mV for the oxygen evolution reaction (OER) and 164 mV for the hydrogen evolution reaction (HER) at 10 mA cm-2 in 1 m KOH, respectively. Furthermore, when used as both the anode and cathode for overall water splitting, a low cell voltage of 1.62 V is required to reach the current density of 10 mA cm-2 , making the VOOH hollow nanospheres an efficient alternative to water splitting.

Exploring Northwest China's agricultural water-saving strategy: analysis of water use efficiency based on an SE-DEA model conducted in Xi'an, Shaanxi Province.

Science.gov (United States)

Mu, L; Fang, L; Wang, H; Chen, L; Yang, Y; Qu, X J; Wang, C Y; Yuan, Y; Wang, S B; Wang, Y N

Worldwide, water scarcity threatens delivery of water to urban centers. Increasing water use efficiency (WUE) is often recommended to reduce water demand, especially in water-scarce areas. In this paper, agricultural water use efficiency (AWUE) is examined using the super-efficient data envelopment analysis (DEA) approach in Xi'an in Northwest China at a temporal and spatial level. The grey systems analysis technique was then adopted to identify the factors that influenced the efficiency differentials under the shortage of water resources. From the perspective of temporal scales, the AWUE increased year by year during 2004-2012, and the highest (2.05) was obtained in 2009. Additionally, the AWUE was the best in the urban area at the spatial scale. Moreover, the key influencing factors of the AWUE are the financial situations and agricultural water-saving technology. Finally, we identified several knowledge gaps and proposed water-saving strategies for increasing AWUE and reducing its water demand by: (1) improving irrigation practices (timing and amounts) based on compatible water-saving techniques; (2) maximizing regional WUE by managing water resources and allocation at regional scales as well as enhancing coordination among Chinese water governance institutes.

Ecosystem-level water-use efficiency inferred from eddy covariance data: definitions, patterns and spatial up-scaling

Science.gov (United States)

Reichstein, M.; Beer, C.; Kuglitsch, F.; Papale, D.; Soussana, J. A.; Janssens, I.; Ciais, P.; Baldocchi, D.; Buchmann, N.; Verbeeck, H.; Ceulemans, R.; Moors, E.; Köstner, B.; Schulze, D.; Knohl, A.; Law, B. E.

2007-12-01

In this presentation we discuss ways to infer and to interpret water-use efficiency at ecosystem level (WUEe) from eddy covariance flux data and possibilities for scaling these patterns to regional and continental scale. In particular we convey the following: WUEe may be computed as a ratio of integrated fluxes or as the slope of carbon versus water fluxes offering different chances for interpretation. If computed from net ecosystem exchange and evapotranspiration on has to take of counfounding effects of respiration and soil evaporation. WUEe time-series at diurnal and seasonal scale is a valuable ecosystem physiological diagnostic for example about ecosystem-level responses to drought. Most often WUEe decreases during dry periods. The mean growing season ecosystem water-use efficiency of gross carbon uptake (WUEGPP) is highest in temperate broad-leaved deciduous forests, followed by temperate mixed forests, temperate evergreen conifers, Mediterranean broad-leaved deciduous forests, Mediterranean broad-leaved evergreen forests and Mediterranean evergreen conifers and boreal, grassland and tundra ecosystems. Water-use efficiency exhibits a temporally quite conservative relation with atmospheric water vapor pressure deficit (VPD) that is modified between sites by leaf area index (LAI) and soil quality, such that WUEe increases with LAI and soil water holding capacity which is related to texture. This property and tight coupling between carbon and water cycles is used to estimate catchment-scale water-use efficiency and primary productivity by integration of space-borne earth observation and river discharge data.

Yield and water use efficiency of deficit-irrigated maize in a semi ...

African Journals Online (AJOL)

Yield and water use efficiency of deficit-irrigated maize in a semi-arid region of Ethiopia. ... PROMOTING ACCESS TO AFRICAN RESEARCH. AFRICAN JOURNALS ONLINE ... African Journal of Food, Agriculture, Nutrition and Development.

Energy and Water Efficiency on Campus | NREL

Science.gov (United States)

Energy and Water Efficiency on Campus Energy and Water Efficiency on Campus NREL ensures the resiliency of our future energy and water systems through energy efficiency strategies and technologies , renewable energy, and water efficiency on the NREL campus. FY17 Energy Intensity. The South Table Mountain

The {sup 13}C isotope discrimination technique for identifying durum wheat cultivars efficient in uptake and use of water

Energy Technology Data Exchange (ETDEWEB)

Mechergui, M; Snane, M H [Departement de Genie Rural et des Eaux et Forets, Tunis (Tunisia). Inst. National Agronomique de Tunisie

1996-07-01

The water balance model using a neutron moisture probe and the {sup 13}C isotope discrimination method were used in this field to rank durum wheat genotypes for water use efficiency. The results presented focus on the first two years of a five-year study. Eighteen durum wheat cultivars were used in the first experiment. The {sup 13}C/{sup 12}C ratio was measured to examine the correlation between this ratio and the water use efficiency. Total water consumption was calculated and the grain and straw yields and other parameters were also recorded. The results show differences between cultivars with respect to water use efficiency, {sup 13}C discrimination and grain yield. From this experiment, four cultivars were selected for a detailed study in the second year. The data from this study show that there is a positive correlation between grain water use efficiency and {Delta}. Thus, it may be possible to use {Delta} as a tool for screening out water use efficient cultivars in semi-arid regions. (author). 12 refs, 5 figs, 1 tab.

Interaction effects of water salinity and hydroponic growth medium on eggplant yield, water-use efficiency, and evapotranspiration

Directory of Open Access Journals (Sweden)

Farnoosh Mahjoor

2016-06-01

Full Text Available Eggplant (Solanum melongena L. is a plant native to tropical regions of Southeast Asia. The water crisis and drought on the one hand and eggplant greenhouse crop development as one of the most popular fruit vegetables for people on the other hand, led to the need for more research on the use of saline water and water stress to optimize salinity level and their impact on eggplant evapotranspiration and encounter better yield and crop quality. The objective of the present study was to investigate the interactions of water salinity and hydroponic growth medium on qualitative and quantitative properties of eggplant and its water-use efficiency. The study used the factorial experiment based on completely randomized design with three replications of four levels of water salinity (electrical conductivity of 0.8 (control, 2.5, 5, and 7 dS m−1 and three growth media (cocopeat, perlite, and a 50–50 mixture of the two by volume. Total yield, yield components, evapotranspiration, and water-use efficiency were determined during two growing periods, one each in 2012 and 2013. All of these indices decreased significantly as water salinity increased. Water with of 0.8 dS m−1 produced an average eggplant yield of 2510 g per plant in 2012 and 2600 g in 2013. The highest yield was observed in cocopeat. Water with 7 dS m−1 reduced yield to 906 g per plant in 2012 and to 960 g in 2013. Lowest yield was observed in perlite. The highest evapotranspiration values occurred in cocopeat at the lowest salinity in both years. Cocopeat and the cocopeat–perlite mixture were equally good substrates. The mixture significantly improved the quantitative and qualitative properties of eggplant yield.

Carbon-13 discrimination as a criterion for identifying high water use efficiency wheat cultivars under water deficit conditions

International Nuclear Information System (INIS)

Bazza, M.

1996-01-01

During four consecutive years, 20 durum wheat (Triticum durum Desf) and bread wheat (Triticum aestrivum L.) cultivars were grown under rain-fed conditions and supplementary irrigation with the objective of assessing the possibility of using 13 C discrimination Δ as a criterion to screen for wheat cultivars that produce high yields and have a better water use efficiency under water deficit conditions. In all four growing season, both treatments were subjected to some water stress which was higher under rain-fed conditions and varied according to the intensity and time of rainfall. During the first growing season, and despite small differences between the two treatments in terms of the amounts of water used, the grain and straw yields as well as Δ were significantly higher in the treatment which received an irrigation at installation than in the one without irrigation. There was substantial genotypic variation in Δ. When both treatments were considered, the total above ground dry matter yield and grain yield were positively correlated with Δ although the correlation coefficient of grain yield versus Δ was not high ( ** ). The data suggest that while a high Δ value may be used as a criterion for selection of cultivars of wheat with potential for high yield and high water use efficiency in wheat under field conditions, caution must be exercised in the selection process as the size of the canopy and the changes in environmental factors mainly soil water content, can result in changes in Δ and the yield of a cultivar. However, Δ of a genotype can also provide valuable information with respect to plant parameters responsible for the control of Δ and this information can be usefully employed in breeding programmes aimed at developing wheat cultivars high in yield and high in water use efficiency, and suitable for cultivation in arid and semi-arid regions of the tropics and sub-tropics. 11 refs, 2 figs, 2 tabs

Carbon-13 discrimination as a criterion for identifying high water use efficiency wheat cultivars under water deficit conditions

Energy Technology Data Exchange (ETDEWEB)

Bazza, M [Rabat-Institus, Rabat (Morocco). Inst. Agronomique et Veterinaire Hassan II

1996-07-01

During four consecutive years, 20 durum wheat (Triticum durum Desf) and bread wheat (Triticum aestrivum L.) cultivars were grown under rain-fed conditions and supplementary irrigation with the objective of assessing the possibility of using {sup 13}C discrimination {Delta} as a criterion to screen for wheat cultivars that produce high yields and have a better water use efficiency under water deficit conditions. In all four growing season, both treatments were subjected to some water stress which was higher under rain-fed conditions and varied according to the intensity and time of rainfall. During the first growing season, and despite small differences between the two treatments in terms of the amounts of water used, the grain and straw yields as well as {Delta} were significantly higher in the treatment which received an irrigation at installation than in the one without irrigation. There was substantial genotypic variation in {Delta}. When both treatments were considered, the total above ground dry matter yield and grain yield were positively correlated with {Delta} although the correlation coefficient of grain yield versus {Delta} was not high (< 0.45{sup **}). The data suggest that while a high {Delta} value may be used as a criterion for selection of cultivars of wheat with potential for high yield and high water use efficiency in wheat under field conditions, caution must be exercised in the selection process as the size of the canopy and the changes in environmental factors mainly soil water content, can result in changes in {Delta} and the yield of a cultivar. But, {Delta} of a genotype can also provide valuable information with respect to plant parameters responsible for the control of {Delta} and this information can be usefully employed in breeding programmes aimed at developing wheat cultivars high in yield and high in water use efficiency, and suitable for cultivation in arid and semi-arid regions of the tropics and sub-tropics. 11 refs,2figs,2tabs.

How efficiently do corn- and soybean-based cropping systems use water? A systems modeling analysis.

Science.gov (United States)

Dietzel, Ranae; Liebman, Matt; Ewing, Robert; Helmers, Matt; Horton, Robert; Jarchow, Meghann; Archontoulis, Sotirios

2016-02-01

Agricultural systems are being challenged to decrease water use and increase production while climate becomes more variable and the world's population grows. Low water use efficiency is traditionally characterized by high water use relative to low grain production and usually occurs under dry conditions. However, when a cropping system fails to take advantage of available water during wet conditions, this is also an inefficiency and is often detrimental to the environment. Here, we provide a systems-level definition of water use efficiency (sWUE) that addresses both production and environmental quality goals through incorporating all major system water losses (evapotranspiration, drainage, and runoff). We extensively calibrated and tested the Agricultural Production Systems sIMulator (APSIM) using 6 years of continuous crop and soil measurements in corn- and soybean-based cropping systems in central Iowa, USA. We then used the model to determine water use, loss, and grain production in each system and calculated sWUE in years that experienced drought, flood, or historically average precipitation. Systems water use efficiency was found to be greatest during years with average precipitation. Simulation analysis using 28 years of historical precipitation data, plus the same dataset with ± 15% variation in daily precipitation, showed that in this region, 430 mm of seasonal (planting to harvesting) rainfall resulted in the optimum sWUE for corn, and 317 mm for soybean. Above these precipitation levels, the corn and soybean yields did not increase further, but the water loss from the system via runoff and drainage increased substantially, leading to a high likelihood of soil, nutrient, and pesticide movement from the field to waterways. As the Midwestern United States is predicted to experience more frequent drought and flood, inefficiency of cropping systems water use will also increase. This work provides a framework to concurrently evaluate production and

Evaluating multiple indices of agricultural water use efficiency and productivity to improve comparisons between sites and trends

Science.gov (United States)

Levy, M. C.

2012-12-01

Approximately 70% of global available freshwater supplies are used in the agricultural sector. Increased demands for water to meet growing population food requirements, and expected changes in the reliability of freshwater supplies due to climate change, threaten the sustainability of water supplies worldwide - not only on farms, but in connected cities and industries. Researchers concerned with agricultural water use sustainability use a variety of theoretical and empirical measures of efficiency and productivity to gain insight into the sustainability of agricultural water use. However, definitions of measures, or indices, vary between different natural and political boundaries, across regions, states and nations and between their respective research, industry, and environmental groups. Index development responds to local data availability and local agendas, and there is debate about the validity of various indices. However, real differences in empirical index measures are not well-understood across the multiple disciplines that study agricultural water use, including engineering and hydrology, agronomy, climate and soil sciences, and economics. Nevertheless reliable, accessible, and generalizable indices are required for planners and policymakers to promote sustainable water use systems. This study synthesizes a set of water use efficiency and productivity indices based on academic, industry and government literature in California and Australia, two locations with similarly water-stressed and valuable agricultural industries under pressure to achieve optimal water use efficiency and productivity. Empirical data at the irrigation district level from the California San Joaquin Valley and Murray Darling Basin states of Victoria and New South Wales in Australia are used to compute indices that estimate efficiency, yield productivity, and economic productivity of agricultural water use. Multiple index estimates of same time-series data demonstrate historical spread

Water use efficiency and functional traits of a semiarid shrubland

Science.gov (United States)

Perez-Priego, Oscar; Lopez-Ballesteros, Ana; Sánchez-Cañete, Enrique P.; Serrano-Ortiz, Penélope; Carrara, Arnaud; Palomares-Palacio, Agustí; Oyonarte, Cecilio; Domingo, Francisco; Kowalski, Andrew S.

2013-04-01

In semiarid climates, water is the fundamental factor determining ecosystem productivity and thereby the capacity for carbon sequestration. Increased water use efficiency (WUE), the ratio of carbon dioxide assimilation (canopy photosynthesis, Pc) to water transpired (canopy evaporation, Ec), is assumed to be an adaptive strategy for sclerophyll shrublands to improve productivity and stress resistance in water-limited environments. However, the real complexity of WUE lies in its dependence on both plant physiological traits (e.g. stomatal resistance, photosynthetic capacity, leaf chemical composition, structure) and on environmental conditions (e.g. atmospheric CO2 concentration, vapour pressure deficit, temperature, light, soil water availability). We used a transient-state closed canopy-chamber to characterise CO2 and water vapour exchanges at the whole plant scale under different environmental conditions and phenological stages. Diurnal and seasonal variations in Pc, Ec and WUE were explained by both physiological and environmental variables. All species showed symmetric patterns in both Pc and Ec when not water limited, but asymmetry during summer drought when leaf water potential was low. During drought, grasses (Festuca sp.) showed a marked decline in functioning (Pc and Ec), whereas shrubs (Genista sp., Hormathophylla sp.) maintained spring-like assimilation rates all morning until stomatal controls shut down gas exchanges. While grasses showed the highest WUE when not water limited, their near senescence during summer drought yielded the lowest WUE. Shrubs showed reduced WUE under moderate drought stress, in contradiction to the assumptions made in global ecosystem models. The importance of the appropriate time-scale for calculating WUE (daily versus hourly), together with water use strategies and ecological functions of individual species, will be further discussed.

Biomass production and water use efficiency in perennial grasses during and after drought stress

DEFF Research Database (Denmark)

Sørensen, Kirsten Kørup; Lærke, Poul Erik; Sørensen, Helle Baadsgaard

2018-01-01

be suitable for assessment of drought stress. There were indications of positive associations between plants carbon isotope composition and water use efficiency (WUE) as well as DM under well-watered conditions. Compared to control, drought-treated plots showed increased growth in the period after drought...... stress. Thus, the drought events did not affect total biomass production (DMtotal) of the whole growing season. During drought stress and the whole growing season, WUE was higher in drought-treated compared to control plots, so it seems possible to save water without loss of biomass. Across soil types, M......Drought is a great challenge to agricultural production, and cultivation of drought-tolerant or water use-efficient cultivars is important to ensure high biomass yields for bio-refining and bioenergy. Here, we evaluated drought tolerance of four C3 species, Dactylis glomerata cvs. Sevenop and Amba...

Studies on {sup 13}C isotope discrimination for identifying tree provenances efficient in water use under water deficit conditions in Kenya

Energy Technology Data Exchange (ETDEWEB)

Nyamai, D O; Juma, P O [Kenya Forestry Research Inst., Nairobi (Kenya). Agroforestry Research Programme

1996-07-01

Screening for drought resistance traits was conducted in a semi-arid site in Machakos using 11 provenances of Acacia tortilis, 6 provenances of Prosopis juliflora and 4 provenances of Casuarina equisetifolia. Tolerance to drought was assessed by the {sup 13}C isotope discrimination ({Delta}) technique as well as by determining the waster use efficiency (WUE). Measurements of dry matter and early growth performance were also taken as indicators of drought resistance. The results showed significant differences in the {sup 13}C Isotope discrimination, water use efficiency and dry matter yields by the different provenances tested. Generally, the results indicated that there were significant linear negative relationships between {sup 13}C discrimination with water use efficiency as well as dry matter yield. The results further showed highly significant positive relationship between dry matter yield and water use efficiency. Acacia tortilis provenances from middle East and neighbouring North Eastern Africa region appear to possess the greatest abilities for drought resistance in comparison with those from sub-saharan Africa as indicated by their {sup 13}C Isotope discrimination levels, dry matter yield and water use efficiency. However, Acacia provenance from Israel had the highest drought resistance trail. Prosopis provenance from Costa Rica and Casuarina from Dakar region in Senegal also emerged as the best provenances in terms of drought tolerance as shown by the {sup 13}C isotope discrimination and dry matter traits. (author). 8 refs, 4 figs, 3 tabs.

Efficient dynamic scarcity pricing in urban water supply

Science.gov (United States)

Lopez-Nicolas, Antonio; Pulido-Velazquez, Manuel; Rougé, Charles; Harou, Julien J.; Escriva-Bou, Alvar

2017-04-01

Water pricing is a key instrument for water demand management. Despite the variety of existing strategies for urban water pricing, urban water rates are often far from reflecting the real value of the resource, which increases with water scarcity. Current water rates do not bring any incentive to reduce water use in water scarcity periods, since they do not send any signal to the users of water scarcity. In California, the recent drought has spurred the implementation of drought surcharges and penalties to reduce residential water use, although it is not a common practice yet. In Europe, the EU Water Framework Directive calls for the implementation of new pricing policies that assure the contribution of water users to the recovery of the cost of water services (financial instrument) while providing adequate incentives for an efficient use of water (economic instrument). Not only financial costs should be recovered but also environmental and resource (opportunity) costs. A dynamic pricing policy is efficient if the prices charged correspond to the marginal economic value of water, which increases with water scarcity and is determined by the value of water for all alternative uses in the basin. Therefore, in the absence of efficient water markets, measuring the opportunity costs of scarce water can only be achieved through an integrated basin-wide hydroeconomic simulation approach. The objective of this work is to design a dynamic water rate for urban water supply accounting for the seasonal marginal value of water in the basin, related to water scarcity. The dynamic pricing policy would send to the users a signal of the economic value of the resource when water is scarce, therefore promoting more efficient water use. The water rate is also designed to simultaneously meet the expected basic requirements for water tariffs: revenue sufficiency (cost recovery) and neutrality, equity and affordability, simplicity and efficiency. A dynamic increasing block rate (IBR

Intrinsic climate dependency of ecosystem light and water-use-efficiencies across Australian biomes

International Nuclear Information System (INIS)

Shi, Hao; Li, Longhui; Eamus, Derek; Cleverly, James; Huete, Alfredo; Yu, Qiang; Beringer, Jason; Van Gorsel, Eva; Hutley, Lindsay

2014-01-01

The sensitivity of ecosystem gross primary production (GPP) to availability of water and photosynthetically active radiation (PAR) differs among biomes. Here we investigated variations of ecosystem light-use-efficiency (eLUE: GPP/PAR) and water-use-efficiency (eWUE: GPP/evapotranspiration) among seven Australian eddy covariance sites with differing annual precipitation, species composition and temperature. Changes to both eLUE and eWUE were primarily correlated with atmospheric vapor pressure deficit (VPD) at multiple temporal scales across biomes, with minor additional correlations observed with soil moisture and temperature. The effects of leaf area index on eLUE and eWUE were also relatively weak compared to VPD, indicating an intrinsic dependency of eLUE and eWUE on climate. Additionally, eLUE and eWUE were statistically different for biomes between summer and winter, except eWUE for savannas and the grassland. These findings will improve our understanding of how light- and water-use traits in Australian ecosystems may respond to climate change. (letter)

Variation in water-use efficiency and delta-C-13 levels in eucalyptus-grandis clones

CSIR Research Space (South Africa)

Olbrich, BW

1993-10-01

Full Text Available Water Status, Vol. 2. Centennial of Utah State University, 6 10 July, 1987, Logan, Utah, pp. 307--311. Hubick, K.T., Farquhar, G.D. and Shorter, R., 1986. Correlation between water-use efficiency and carbon isotope...

The potential of Vachellia kosiensis (Acacia kosiensis) as a dryland forestry species in terms of its water use, growth rates and resultant water-use efficiency

CSIR Research Space (South Africa)

Gush, Mark B

2017-01-01

Full Text Available , their correspondingly low water-use rates indicated that the indigenous trees had similar biophysical water-use efficiency values compared with genetically improved introduced tree species and highlighted their potential as an attractive land-use option in appropriate...

WATER CONSUMPTION AND WATER USE EFFICIENCY OF CASTOR BEAN PARAGUAÇÚ CULTIVAR SUBMITTED TO NITROGEN FERTILIZATION

OpenAIRE

Lucia Helena Garófalo Chaves; Hans Raj Ghey; Susane Ribeiro

2011-01-01

Although the productivity of castor bean reduces under water deficit it is considered resistant to low precipitation conditions, thus constituting an alternative form of income for the semi-arid. The scarce information about the effect of nitrogen fertilization on water consumption and efficiency of use motivated this study. The study was conducted in a greenhouse located at the Federal University of Campina Grande – Campus I, with plants arranged in a factorial design with three replications...

Tomato Yield and Water Use Efficiency - Coupling Effects between Growth Stage Specific Soil Water Deficits

DEFF Research Database (Denmark)

Chen, Si; Zhenjiang, Zhou; Andersen, Mathias Neumann

2015-01-01

To investigate the sensitivity of tomato yield and water use efficiency (WUE) to soil water content at different growth stages, the central composite rotatable design (CCRD) was employed in a five-factor-five-level pot experiment under regulated deficit irrigation. Two regression models concerning...... the effects of stage-specific soil water content on tomato yield and WUE were established. The results showed that the lowest available soil water (ASW) content (around 28%) during vegetative growth stage (here denoted θ1) resulted in high yield and WUE. Moderate (around 69% ASW) during blooming and fruit...... effects of ASW in two growth stages were between θ2 and θ5, θ3. In both cases a moderate θ2 was a precondition for maximum yield response to increasing θ5 and θ3. Sensitivity analysis revealed that yield was most sensitive to soil water content at fruit maturity (θ5). Numerical inspection...

Variability in leaf surface features and water efficiency utilisation in ...

African Journals Online (AJOL)

The C4 form was found to be more efficient with respect to water utilization efficiency. Keywords: alloteropsis semialata; botany; characteristics; distribution; grasses; leaves; photosynthetic rate; plant physiology; south africa; stomatal resistance; transpiration rate; transvaal highveld; water use efficiency; water utilization ...

Contrasting effects of invasive insects and fire on ecosystem water use efficiency

Science.gov (United States)

K.L. Clark; N.S. Skowronski; M.R. Gallagher; H. Renninger; K.V.R. Schäfer

2014-01-01

We used eddy covariance and meteorological measurements to estimate net ecosystem exchange of CO2 (NEE), gross ecosystem production (GEP), evapotranspiration (Et), and ecosystem water use efficiency (WUEe; calculated as GEP / Et during dry canopy conditions) in three upland forests in the New Jersey Pinelands, USA, that were defoliated by gypsy...

Increasing water use efficiency along the C3 to C4 evolutionary pathway: a stomatal optimization perspective.

Science.gov (United States)

Way, Danielle A; Katul, Gabriel G; Manzoni, Stefano; Vico, Giulia

2014-07-01

C4 photosynthesis evolved independently numerous times, probably in response to declining atmospheric CO2 concentrations, but also to high temperatures and aridity, which enhance water losses through transpiration. Here, the environmental factors controlling stomatal behaviour of leaf-level carbon and water exchange were examined across the evolutionary continuum from C3 to C4 photosynthesis at current (400 μmol mol(-1)) and low (280 μmol mol(-1)) atmospheric CO2 conditions. To this aim, a stomatal optimization model was further developed to describe the evolutionary continuum from C3 to C4 species within a unified framework. Data on C3, three categories of C3-C4 intermediates, and C4 Flaveria species were used to parameterize the stomatal model, including parameters for the marginal water use efficiency and the efficiency of the CO2-concentrating mechanism (or C4 pump); these two parameters are interpreted as traits reflecting the stomatal and photosynthetic adjustments during the C3 to C4 transformation. Neither the marginal water use efficiency nor the C4 pump strength changed significantly from C3 to early C3-C4 intermediate stages, but both traits significantly increased between early C3-C4 intermediates and the C4-like intermediates with an operational C4 cycle. At low CO2, net photosynthetic rates showed continuous increases from a C3 state, across the intermediates and towards C4 photosynthesis, but only C4-like intermediates and C4 species (with an operational C4 cycle) had higher water use efficiencies than C3 Flaveria. The results demonstrate that both the marginal water use efficiency and the C4 pump strength increase in C4 Flaveria to improve their photosynthesis and water use efficiency compared with C3 species. These findings emphasize that the advantage of the early intermediate stages is predominantly carbon based, not water related. © The Author 2014. Published by Oxford University Press on behalf of the Society for Experimental Biology.

Towards physiologically meaningful water-use efficiency estimates from eddy covariance data.

Science.gov (United States)

Knauer, Jürgen; Zaehle, Sönke; Medlyn, Belinda E; Reichstein, Markus; Williams, Christopher A; Migliavacca, Mirco; De Kauwe, Martin G; Werner, Christiane; Keitel, Claudia; Kolari, Pasi; Limousin, Jean-Marc; Linderson, Maj-Lena

2018-02-01

Intrinsic water-use efficiency (iWUE) characterizes the physiological control on the simultaneous exchange of water and carbon dioxide in terrestrial ecosystems. Knowledge of iWUE is commonly gained from leaf-level gas exchange measurements, which are inevitably restricted in their spatial and temporal coverage. Flux measurements based on the eddy covariance (EC) technique can overcome these limitations, as they provide continuous and long-term records of carbon and water fluxes at the ecosystem scale. However, vegetation gas exchange parameters derived from EC data are subject to scale-dependent and method-specific uncertainties that compromise their ecophysiological interpretation as well as their comparability among ecosystems and across spatial scales. Here, we use estimates of canopy conductance and gross primary productivity (GPP) derived from EC data to calculate a measure of iWUE (G 1 , "stomatal slope") at the ecosystem level at six sites comprising tropical, Mediterranean, temperate, and boreal forests. We assess the following six mechanisms potentially causing discrepancies between leaf and ecosystem-level estimates of G 1 : (i) non-transpirational water fluxes; (ii) aerodynamic conductance; (iii) meteorological deviations between measurement height and canopy surface; (iv) energy balance non-closure; (v) uncertainties in net ecosystem exchange partitioning; and (vi) physiological within-canopy gradients. Our results demonstrate that an unclosed energy balance caused the largest uncertainties, in particular if it was associated with erroneous latent heat flux estimates. The effect of aerodynamic conductance on G 1 was sufficiently captured with a simple representation. G 1 was found to be less sensitive to meteorological deviations between canopy surface and measurement height and, given that data are appropriately filtered, to non-transpirational water fluxes. Uncertainties in the derived GPP and physiological within-canopy gradients and their

Evaluation of Water Efficiency in Green Building in Taiwan

Directory of Open Access Journals (Sweden)

Cheng-Li Cheng

2016-06-01

Full Text Available Low carbon policies, including those aimed at increasing water efficiency, have been adopted as a crucial strategy for combating global warming and climate change. The green building evaluation system used in Taiwan was first applied in 1999 and initially utilized a building’s water efficiency as the threshold index for determining the building’s environmental impact. Since 1999, more than a thousand buildings have been certified as green buildings using this evaluation system. The quantitative effects of water conservation efforts should be provided to policy makers as a form of positive feedback. To that end, the present study offers a calculation process for estimating the quantitative volume of water saved by practical green buildings. The baseline water usage for all kinds of buildings was determined to serve as the criterion for determining the water-saving efficiency of individual buildings. An investigation of the average water-saving rate from 2000 to 2013 for 1320 buildings certified as green buildings was also conducted to validate the estimation results and found that these green buildings saved an average of approximately 37.6% compared to the baseline water usage rate for all buildings. Water savings will inevitably follow from the use of water-saving appliances or water-saving designs for buildings. The proposed calculation process can be used to clarify the relationships between specific water-saving concepts and the real water usage efficiency of green buildings.

Improving Energy Efficiency and Enabling Water Recycle in Biorefineries Using Bioelectrochemical Cells

International Nuclear Information System (INIS)

Borole, Abhijeet P.

2010-01-01

Improving biofuel yield and water reuse are two important issues in further development of biorefineries. The total energy content of liquid fuels (including ethanol and hydrocarbon) produced from cellulosic biomass via biochemical or hybrid bio-thermochemical routes can vary from 49% to 70% of the biomass entering the biorefinery, on an energy basis. Use of boiler for combustion of residual organics and lignin results in significant energy and water losses. An alternate process to improve energy recovery from the residual organic streams is via use of bioelectrochemical systems such as microbial fuel cells (MFCs) microbial electrolysis cells (MECs). The potential advantages of this alternative scheme in a biorefinery include minimization of heat loss and generation of a higher value product, hydrogen. The need for 5-15 gallons of water per gallon of ethanol can be reduced significantly via recycle of water after MEC treatment. Removal of inhibitory byproducts such as furans, phenolics and acetate in MFC/MECs to generate energy, thus, has dual advantages including improvements in energy efficiency and ability to recycle water. Conversion of the sugar- and lignin- degradation products to hydrogen is synergistic with biorefinery hydrogen requirements for upgrading F-T liquids and other byproducts to high-octane fuels and/or high value products. Some of these products include sorbitol, succinic acid, furan and levulinate derivatives, glycols, polyols, 1,4-butenadiol, phenolics polymers, etc. Potential process alternatives utilizing MECs in biorefineries capable of improving energy efficiency by up to 30% are discussed.

The Water Efficiency Paradox, a study of Central Asia

Science.gov (United States)

Merks, Joreen; Bastiaanssen, Wim

2017-04-01

Water scarcity is a rapidly growing concern in the semi-arid areas of Central Asia. Water savings and efficiency improvement programs are promoted as a possibility to save the Aral Sea. The Aral Seas lost 92% of its volume between 1960 and 2009. Projects on rehabilitating the Aral Sea and increasing the efficiency of water use in the irrigation sector are, however, not making progress. In Central Asia, 90% of the water withdrawal is allocated to agriculture. Irrigation efficiency programs often disregard the downstream connectivity of the water flow path. Not all water being applied is consumed by crop evapotranspiration and in fact an equally great portion of water returns back into the river basin system and is reused downstream. This cascade effect implies that results in one location can induce a scarcity of water in another location. The cascade effect in the Syr Darya has been studied by means of the Aral Sea Basin Management Model (ASBMM) designed by SIC-ICWC and remote sensing data produced by UNESCO-IHE. We will demonstrate the impact of increasing irrigation efficiency locally on the overall water consumption in the basin. We will show that efficiency increases with larger areas, and that there are caps to the maximum efficiency at basin scale. Increasing efficiency is thus not self-evident. Classical solutions on promoting increase of efficiency and water savings are therefore outdated and misleads stakeholders. We will look into the misconceptions and challenges in the communication between researchers and policy makers regarding increasing efficiency.

Water conservation quantities vs customer opinion and satisfaction with water efficient appliances in Miami, Florida.

Science.gov (United States)

Lee, Mengshan; Tansel, Berrin

2013-10-15

During 2006-2007, Miami-Dade County, Florida, USA, provided incentives for low income and senior residents in single family homes for retrofitting with high efficiency fixtures. The participating residences were retrofitted with high-efficiency toilets, showerheads, and aerators. In 2012, a telephone survey was conducted to evaluate the satisfaction of the participants and the associated effects on water conservation practices. This study evaluates the attitudes and opinions of the participants relative to water use efficiency measures and the actual reduction in water consumption characteristics of the participating households. The participant characteristics were analyzed to identify correlations between the socio-demographic factors, program satisfaction and actual water savings. Approximately 65.5% of the survey respondents reported changes in their water use habits and 76.6% reported noticeable reduction in their water bills. The analyses showed that the satisfaction levels of the participants were closely correlated with the actual water savings. The results also showed that satisfaction level along with water saving potential (i.e., implementation of water efficiency devices) or change of water use habits has provided positive synergistic effect on actual water savings. The majority of the participants surveyed (81.3-89.1%) reported positive attitudes for water conservation incentive program and the benefits of the high efficiency fixtures. Copyright © 2013 Elsevier Ltd. All rights reserved.

Highly efficient photochemical HCOOH production from CO2 and water using an inorganic system

Directory of Open Access Journals (Sweden)

Satoshi Yotsuhashi

2012-12-01

Full Text Available We have constructed a system that uses solar energy to react CO2 with water to generate formic acid (HCOOH at an energy conversion efficiency of 0.15%. It consists of an AlGaN/GaN anode photoelectrode and indium (In cathode that are electrically connected outside of the reactor cell. High energy conversion efficiency is realized due to a high quantum efficiency of 28% at 300 nm, attributable to efficient electron-hole separation in the semiconductor's heterostructure. The efficiency is close to that of natural photosynthesis in plants, and what is more, the reaction product (HCOOH can be used as a renewable energy source.

Understanding the Spatiotemporal Variability of Inherent Water Use Efficiency

Science.gov (United States)

Boese, Sven; Jung, Martin; Carvalhais, Nuno; Reichstein, Markus

2015-04-01

The global carbon and water cycles are coupled via plant physiology. However, the resulting spatial and temporal covariability of both fluxes on a global scale lacks sufficient understanding. This is required to estimate the impact of atmospheric drought on photosynthesis in water-limited ecosystems. Water use efficiency (WUE) is an essential ecosystem diagnostic defined as the ratio between gross primary productivity (GPP) and transpiration (T). WUE is known to vary with vapour-pressure deficit (VPD) and therefore also in time. The inherent water use efficiency (iWUE) accounts for the VPD effect on WUE and aims at representing a largely time-invariant ecosystem property. However, different ways of describing the functional response of iWUE to VPD are found in the literature. One established iWUE definition was proposed by Beer et al. (2009) and takes the form of iWUE = GPP--VPD- . T (1) A similar definition can be derived from stomatal conductance theories such as Katul et al. (2010) and takes the form of √ -- GPP---VPD- iWUE = T . (2) Here, we use eddy covariance measurements from the FLUXNET database to evaluate both approaches for a globally representative set of biomes including tropical, temperate and semi-arid ecosystems. Testing both definitions in a model-data fusion setup indicated that (2) is more consistent with FLUXNET observations than (1). However, there still remains considerable temporal variability of iWUE which is linked to seasonal changes in VPD. To explore up to which extent the temporal variability of iWUE may be related to the prescribed functional responses to VPD, we treated the exponent of VPD as a global parameter, here termed γ. When γ = 1 the functional response is equivalent to (1), while when γ = 0.5 it corresponds to formulation of model (2)). The global estimate was found to be significantly lower than 0.5, which would have been expected from stomatal conductance theory at leaf level. We assessed whether adding γ as site

Improving Water Use Efficiency of Lettuce (Lactuca sativa L.) Using Phosphorous Fertilizers.

Science.gov (United States)

Alkhader, Asad M F; Abu Rayyan, Azmi M

2013-01-01

A greenhouse pot experiment was conducted to evaluate the effect of phosphorous (P) fertilizers application to an alkaline calcareous soil on the water use efficiency (WUE) of lettuce cultivar "robinson" of iceberg type. Head fresh and dry weights, total water applied and WUE were affected significantly by the P fertilizer type and rate. P fertilizers addition induced a significant enhancement in the WUE and fresh and dry weights of the crop. A local phosphate rock (PR) applied directly was found to be inferior to the other types of P fertilizers (Mono ammonium phosphate (MAP), Single superphosphate (SSP), and Di ammonium phosphate ((DAP)). MAP fertilizer at 375 and 500 kg P2O5/ha application rates recorded the highest significant values of head fresh weight and WUE, respectively.

Supplemental irrigation to improve wheat production and water use efficiency under rainfed farming conditions

International Nuclear Information System (INIS)

Hussain, Q.; Bhatti, A.A.; Ahmad, M.M.

2007-01-01

The stochastic behaviors of rainfall pose serious limitations for sustained and profitable crop production in rainfed areas; farmers hesitate to apply fertilizers when they are not sure about rainfall. In view of these limitations a research study was conducted for three years (2003-2006) at field station of Water Resources Research Institute (WRRI), National Agricultural Research Centre(NARC), Islamabad to examine the effects of supplemental irrigation (SI) on wheat production and water use efficiency (WUE). Irrigation treatments employed under the experiment were: i) Rainfed without irrigation and fertilizer application (I/sub 0/); ii) SI of 25 mm was applied to non-fertilizer field at 75% management allowed deficit (MAD)(I/sub 1/); iii) Rainfed with fertilizer application at sowing time (I/sub 2/); and iv) SI of 25 mm was applied at 75% MAD and at the time of fertilizer application as top dressing (I/sub 3/). Supplemental irrigation increased the crop yield during the years 2003-2006 under both fertilizer and non-fertilizer conditions. Increased in grain yield under non-fertilizer conditions (I/sub 1/) ranges between 770-980 kg/ha, which is 27 to 48% higher than the rainfed yield (I/sub 0/). Supplemental irrigation and split application of fertilizer (treatment I/sub 3/) increased in grain yield within the range of 1000-1350 kg/ha, which is 27-49% higher than yield under treatment I/sub 2/. Whereas, due to synergetic effect of supplemental irrigation and fertilizer application, increased in grain yield ranges between 1550-2030 kg/ha, which is 49% to 100% higher than the rainfed and non-fertilizer field. WUE was calculated for rain (WUE/sub r/) for total water (grass: previous soil water storage + rain + irrigation) (WUE/sub g/), for SI water only (WUE/sub si/) and for synergetic effect (SI water + fertilizer application) (WUE/sub sis/) Water use efficiencies namely the WUE/sub r/, WUE/sub g/ and WUE/sub si/ during the period of three years under non fertilizer

Biomass and biomass water use efficiency in oilseed crop (Brassica juncea L.) under semi-arid microenvironments

International Nuclear Information System (INIS)

Adak, Tarun; Kumar, Gopal; Chakravarty, N.V.K.; Katiyar, R.K.; Deshmukh, P.S.; Joshi, H.C.

2013-01-01

Biomass production in arid and semi-arid regions requires a special attention owing to spatiotemporal scarcity of irrigation water wherein improved water use efficiency (WUE) of the crop is targeted. Under field conditions, the crop undergoes dynamic changes in near ground or within-canopy microenvironments. This changed microclimatic condition may have an impact on phenological response of the oilseed crop which in turn would affect biomass productivity, economic seed yield and water use efficiency of the crop. Henceforth, quantification of biomass production and its WUE of oilseed Brassica crop is essentially required owing to have better understanding of the crop water requirement under the era of climate change. Following a 2 years field experiment, it was revealed that the changes in leaf area index were explained by about 68–74%. The best fit polynomial third order regression analysis indicated >93% prediction in biomass production as a function of time factor. Improved biomass partitioning into economic sinks was also observed. Small scale change in near ground microenvironment may reduce the prediction of biomass variability to the extent of 3%. The mean ET variations were observed as 2.4, 1.5 and 3.2 mm day −1 during the critical phenological stages. Mean seed yield, biomass WUE and seed yield WUE ranged between 2.71 and 2.87 Mg ha −1 , 11.4 and 13.1 g m −2 mm −1 and 19.3 and 22.9 kg ha −1 mm −1 respectively. Variations in both biomass and seed yield water use efficiencies due to small scale change in near ground microclimates were revealed. -- Highlights: ► Assessing biomass productivity and its water use efficiency under arid and semi-arid regions is important. ► Under field conditions, the crop undergoes dynamic changes in near ground or within-canopy microenvironments. ► We have estimated changes in seasonal ET, within-canopy micrometeorological dynamics. ► Biomass productivity, partitioning and water use efficiencies were

Response of bean cultures' water use efficiency against climate warming in semiarid regions of China.

Science.gov (United States)

Guoju, Xiao; Fengju, Zhang; Juying, Huang; Chengke, Luo; Jing, Wang; Fei, Ma; Yubi, Yao; Runyuan, Wang; Zhengji, Qiu

2016-07-31

Farm crop growing and high efficiency water resource utilizing are directly influenced by global warming, and a new challenge will be given to food and water resource security. A simulation experiment by farm warming with infrared ray radiator was carried out, and the result showed photosynthesis of broad bean was significantly faster than transpiration during the seedling stage, ramifying stage, budding stage, blooming stage and podding stage when the temperate was increased by 0.5-1.5 °C. But broad bean transpiration was faster than photosynthesis during the budding stage, blooming stage and podding stage when the temperature was increased by 1.5 °C above. The number of grain per hill and hundred-grain weight were significantly increased when the temperature was increased by 0.5-1.0 °C. But they significantly dropped and finally the yield decreased when the temperature was increased by 1.0 °C above. The broad bean yield decreased by 39.2-88.4% when the temperature was increased by 1.5-2.0 °C. The broad bean water use efficiency increased and then decreased with temperature rising. The water use efficiency increased when the temperature was increased by 1.0 °C below, and it quickly decreased when the temperature was increased by 1.0 °C above. In all, global warming in the future will significantly influence the growth, yield and water use efficiency of bean cultures in China's semiarid regions.

High efficient ammonia heat pump system for industrial process water using the ISEC concept. Part 1

DEFF Research Database (Denmark)

Rothuizen, Erasmus Damgaard; Madsen, C.; Elmegaard, Brian

2014-01-01

The purpose of the Isolated System Energy Charging (ISEC) is to provide a high-efficient ammonia heat pump system for hot water production. The ISEC concept uses two storage tanks for the water, one discharged and one charged. The charged tank is used for the industrial process while the discharged...... tank, is charging. Charging is done by circulating the water in the tank through the condenser several times and thereby gradually heats the water. This result in a lower condensing temperature than if the water was heated in one step. A dynamic model of the system, implemented in Dymola, is used...... to investigate the performance of the ISEC system. The ISEC concept approaches the efficiency of a number of heat pumps in series and the COP of the system may reach 6.8, which is up to 25 % higher than a conventional heat pump heating water in one step....

Change in terrestrial ecosystem water-use efficiency over the last three decades.

Science.gov (United States)

Huang, Mengtian; Piao, Shilong; Sun, Yan; Ciais, Philippe; Cheng, Lei; Mao, Jiafu; Poulter, Ben; Shi, Xiaoying; Zeng, Zhenzhong; Wang, Yingping

2015-06-01

Defined as the ratio between gross primary productivity (GPP) and evapotranspiration (ET), ecosystem-scale water-use efficiency (EWUE) is an indicator of the adjustment of vegetation photosynthesis to water loss. The processes controlling EWUE are complex and reflect both a slow evolution of plants and plant communities as well as fast adjustments of ecosystem functioning to changes of limiting resources. In this study, we investigated EWUE trends from 1982 to 2008 using data-driven models derived from satellite observations and process-oriented carbon cycle models. Our findings suggest positive EWUE trends of 0.0056, 0.0007 and 0.0001 g C m(-2)  mm(-1)  yr(-1) under the single effect of rising CO2 ('CO2 '), climate change ('CLIM') and nitrogen deposition ('NDEP'), respectively. Global patterns of EWUE trends under different scenarios suggest that (i) EWUE-CO2 shows global increases, (ii) EWUE-CLIM increases in mainly high latitudes and decreases at middle and low latitudes, (iii) EWUE-NDEP displays slight increasing trends except in west Siberia, eastern Europe, parts of North America and central Amazonia. The data-driven MTE model, however, shows a slight decline of EWUE during the same period (-0.0005 g C m(-2)  mm(-1)  yr(-1) ), which differs from process-model (0.0064 g C m(-2)  mm(-1)  yr(-1) ) simulations with all drivers taken into account. We attribute this discrepancy to the fact that the nonmodeled physiological effects of elevated CO2 reducing stomatal conductance and transpiration (TR) in the MTE model. Partial correlation analysis between EWUE and climate drivers shows similar responses to climatic variables with the data-driven model and the process-oriented models across different ecosystems. Change in water-use efficiency defined from transpiration-based WUEt (GPP/TR) and inherent water-use efficiency (IWUEt , GPP×VPD/TR) in response to rising CO2 , climate change, and nitrogen deposition are also discussed. Our analyses will

Cotton Water Use Efficiency under Two Different Deficit Irrigation Scheduling Methods

Directory of Open Access Journals (Sweden)

Jeffrey T. Baker

2015-08-01

Full Text Available Declines in Ogallala aquifer levels used for irrigation has prompted research to identify methods for optimizing water use efficiency (WUE of cotton (Gossypium hirsutum L. In this experiment, conducted at Lubbock, TX, USA in 2014, our objective was to test two canopy temperature based stress indices, each at two different irrigation trigger set points: the Stress Time (ST method with irrigation triggers set at 5.5 (ST_5.5 and 8.5 h (ST_8.5 and the Crop Water Stress Index (CWSI method with irrigation triggers set at 0.3 (CWSI_0.3 and 0.6 (CWSI_0.6. When these irrigation triggers were exceeded on a given day, the crop was deficit irrigated with 5 mm of water via subsurface drip tape. Also included in the experimental design were a well-watered (WW control irrigated at 110% of potential evapotranspiration and a dry land (DL treatment that relied on rainfall only. Seasonal crop water use ranged from 353 to 625 mm across these six treatments. As expected, cotton lint yield increased with increasing crop water use but lint yield WUE displayed asignificant (p ≤ 0.05 peak near 3.6 to 3.7 kg ha−1 mm−1 for the ST_5.5 and CWSI_0.3 treatments, respectively. Our results suggest that WUE may be optimized in cotton with less water than that needed for maximum lint yield.

Irrigation efficiency and water-policy implications for river basin resilience

Science.gov (United States)

Scott, C. A.; Vicuña, S.; Blanco-Gutiérrez, I.; Meza, F.; Varela-Ortega, C.

2014-04-01

Rising demand for food, fiber, and biofuels drives expanding irrigation withdrawals from surface water and groundwater. Irrigation efficiency and water savings have become watchwords in response to climate-induced hydrological variability, increasing freshwater demand for other uses including ecosystem water needs, and low economic productivity of irrigation compared to most other uses. We identify three classes of unintended consequences, presented here as paradoxes. Ever-tighter cycling of water has been shown to increase resource use, an example of the efficiency paradox. In the absence of effective policy to constrain irrigated-area expansion using "saved water", efficiency can aggravate scarcity, deteriorate resource quality, and impair river basin resilience through loss of flexibility and redundancy. Water scarcity and salinity effects in the lower reaches of basins (symptomatic of the scale paradox) may partly be offset over the short-term through groundwater pumping or increasing surface water storage capacity. However, declining ecological flows and increasing salinity have important implications for riparian and estuarine ecosystems and for non-irrigation human uses of water including urban supply and energy generation, examples of the sectoral paradox. This paper briefly considers three regional contexts with broadly similar climatic and water-resource conditions - central Chile, southwestern US, and south-central Spain - where irrigation efficiency directly influences basin resilience. The comparison leads to more generic insights on water policy in relation to irrigation efficiency and emerging or overdue needs for environmental protection.

Improving the water use efficiency of short rotation coppice (SRC) willows

Energy Technology Data Exchange (ETDEWEB)

Stephens, W.; Bonneau, L.; Groves, S.; Armstrong, A.; Lindegard, K.

2003-07-01

On the premise that biofuels will make a significant contribution to the UK's renewable energy sources by the year 2010, willow short rotation coppicing is being studied. The high water requirement of willow is seen as a potential problem in the drier regions of the UK and increasing the water use efficiency and/or draught resistance would extend the areas where willow coppicing would be profitable. The first part of the project was to investigate the water use of a number of near-market varieties of willow and evaluate techniques for early drought tolerance screening in a breeding program and for this, field studies were conducted. This report gives some very early results from the preliminary study. Since DTI funding ceased before the one-season study of the three-year program was complete, the results should be regarded as tentative only. The next phase of the program will be funded by DEFRA and will include efforts to identify how a range of high-yielding willows respond to water stress.

Modelling water uptake efficiency of root systems

Science.gov (United States)

Leitner, Daniel; Tron, Stefania; Schröder, Natalie; Bodner, Gernot; Javaux, Mathieu; Vanderborght, Jan; Vereecken, Harry; Schnepf, Andrea

2016-04-01

Water uptake is crucial for plant productivity. Trait based breeding for more water efficient crops will enable a sustainable agricultural management under specific pedoclimatic conditions, and can increase drought resistance of plants. Mathematical modelling can be used to find suitable root system traits for better water uptake efficiency defined as amount of water taken up per unit of root biomass. This approach requires large simulation times and large number of simulation runs, since we test different root systems under different pedoclimatic conditions. In this work, we model water movement by the 1-dimensional Richards equation with the soil hydraulic properties described according to the van Genuchten model. Climatic conditions serve as the upper boundary condition. The root system grows during the simulation period and water uptake is calculated via a sink term (after Tron et al. 2015). The goal of this work is to compare different free software tools based on different numerical schemes to solve the model. We compare implementations using DUMUX (based on finite volumes), Hydrus 1D (based on finite elements), and a Matlab implementation of Van Dam, J. C., & Feddes 2000 (based on finite differences). We analyse the methods for accuracy, speed and flexibility. Using this model case study, we can clearly show the impact of various root system traits on water uptake efficiency. Furthermore, we can quantify frequent simplifications that are introduced in the modelling step like considering a static root system instead of a growing one, or considering a sink term based on root density instead of considering the full root hydraulic model (Javaux et al. 2008). References Tron, S., Bodner, G., Laio, F., Ridolfi, L., & Leitner, D. (2015). Can diversity in root architecture explain plant water use efficiency? A modeling study. Ecological modelling, 312, 200-210. Van Dam, J. C., & Feddes, R. A. (2000). Numerical simulation of infiltration, evaporation and shallow

Spring maize yield, soil water use and water use efficiency under plastic film and straw mulches in the Loess Plateau

Science.gov (United States)

Lin, Wen; Liu, Wenzhao; Xue, Qingwu

2016-12-01

To compare the soil water balance, yield and water use efficiency (WUE) of spring maize under different mulching types in the Loess Plateau, a 7-year field experiment was conducted in the Changwu region of the Loess Plateau. Three treatments were used in this experiment: straw mulch (SM), plastic film mulch (PM) and conventional covering without mulch (CK). Results show that the soil water change of dryland spring maize was as deep as 300 cm depth and hence 300 cm is recommended as the minimum depth when measure the soil water in this region. Water use (ET) did not differ significantly among the treatments. However, grain yield was significantly higher in PM compared with CK. WUE was significantly higher in PM than in CK for most years of the experiment. Although ET tended to be higher in PM than in the other treatments (without significance), the evaporation of water in the fallow period also decreased. Thus, PM is sustainable with respect to soil water balance. The 7-year experiment and the supplemental experiment thus confirmed that straw mulching at the seedling stage may lead to yield reduction and this effect can be mitigated by delaying the straw application to three-leaf stage.

Effects of limited irrigation on yield and water use efficiency of two ...

African Journals Online (AJOL)

The effects of irrigation on grain yield and water use efficiency was studied on two sequence replaced dryland winter wheat (Triticum aestivum L.) cultivars, Changwu 135 (CW, a new cultivar) and Pingliang 40 (PL, an old cultivar). Field experiments were carried out on Changwu country on Loess Plateau, China. Whereas ...

Irrigation efficiency and water-policy implications for river-basin resilience

Science.gov (United States)

Scott, C. A.; Vicuña, S.; Blanco-Gutiérrez, I.; Meza, F.; Varela-Ortega, C.

2013-07-01

Rising demand for food, fiber, and biofuels drives expanding irrigation withdrawals from surface- and groundwater. Irrigation efficiency and water savings have become watchwords in response to climate-induced hydrological variability, increasing freshwater demand for other uses including ecosystem water needs, and low economic productivity of irrigation compared to most other uses. We identify three classes of unintended consequences, presented here as paradoxes. Ever-tighter cycling of water has been shown to increase resource use, an example of the efficiency paradox. In the absence of effective policy to constrain irrigated-area expansion using "saved water", efficiency can aggravate scarcity, deteriorate resource quality, and impair river-basin resilience through loss of flexibility and redundancy. Water scarcity and salinity effects in the lower reaches of basins (symptomatic of the scale paradox) may partly be offset over the short-term through groundwater pumping or increasing surface water storage capacity. However, declining ecological flows and increasing salinity have important implications for riparian and estuarine ecosystems and for non-irrigation human uses of water including urban supply and energy generation, examples of the sectoral paradox. This paper briefly examines policy frameworks in three regional contexts with broadly similar climatic and water-resource conditions - central Chile, southwestern US, and south-central Spain - where irrigation efficiency directly influences basin resilience. The comparison leads to more generic insights on water policy in relation to irrigation efficiency and emerging or overdue needs for environmental protection.

Effects of soil water and nitrogen availability on photosynthesis and water use efficiency of Robinia pseudoacacia seedlings.

Science.gov (United States)

Liu, Xiping; Fan, Yangyang; Long, Junxia; Wei, Ruifeng; Kjelgren, Roger; Gong, Chunmei; Zhao, Jun

2013-03-01

The efficient use of water and nitrogen (N) to promote growth and increase yield of fruit trees and crops is well studied. However, little is known about their effects on woody plants growing in arid and semiarid areas with limited water and N availability. To examine the effects of water and N supply on early growth and water use efficiency (WUE) of trees on dry soils, one-year-old seedlings of Robinia pseudoacacia were exposed to three soil water contents (non-limiting, medium drought, and severe drought) as well as to low and high N levels, for four months. Photosynthetic parameters, leaf instantaneous WUE (WUEi) and whole tree WUE (WUEb) were determined. Results showed that, independent of N levels, increasing soil water content enhanced the tree transpiration rate (Tr), stomatal conductance (Gs), intercellular CO2 concentration (Ci), maximum net assimilation rate (Amax), apparent quantum yield (AQY), the range of photosynthetically active radiation (PAR) due to both reduced light compensation point and enhanced light saturation point, and dark respiration rate (Rd), resulting in a higher net photosynthetic rate (Pn) and a significantly increased whole tree biomass. Consequently, WUEi and WUEb were reduced at low N, whereas WUEi was enhanced at high N levels. Irrespective of soil water availability, N supply enhanced Pn in association with an increase of Gs and Ci and a decrease of the stomatal limitation value (Ls), while Tr remained unchanged. Biomass and WUEi increased under non-limiting water conditions and medium drought, as well as WUEb under all water conditions; but under severe drought, WUEi and biomass were not affected by N application. In conclusion, increasing soil water availability improves photosynthetic capacity and biomass accumulation under low and high N levels, but its effects on WUE vary with soil N levels. N supply increased Pn and WUE, but under severe drought, N supply did not enhance WUEi and biomass.

Potential of Soil Amendments (Biochar and Gypsum in increasing Water Use Efficiency of Abelmoschus esculentus L. Moench

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Aniqa eBatool

2015-09-01

Full Text Available Water being an essential component for plant growth and development, its scarcity poses serious threat to crops around the world. Climate changes and global warming are increasing the temperature of earth hence becoming an ultimate cause of water scarcity. It is need of the day to use potential soil amendments that could increase the plants’ resistance under such situations. Biochar and gypsum were used in the present study to improve the water use efficiency and growth of Abelmoschus esculentus L. Moench (Lady’s Finger. A six weeks experiment was conducted under greenhouse conditions. Stress treatments were applied after thirty days of sowing. Plant height, leaf area, photosynthesis, transpiration rate, stomatal conductance and water use efficiency were determined weekly under stressed (60% field capacity and non-stressed (100% field capacity conditions. Stomatal conductance and transpiration rate decreased and reached near to zero in stressed plants. Stressed plants also showed resistance to water stress upto five weeks and gradually perished at sixth week. On the other hand, water use efficiency improved in stressed plants containing biochar and gypsum as compared to untreated plants. Biochar alone is a better strategy to promote plant growth and WUE specifically of Abelmoschus esculentus, compared to its application in combination with gypsum.

Impact of controlled release urea on maize yield and nitrogen use efficiency under different water conditions.

Directory of Open Access Journals (Sweden)

Guanghao Li

Full Text Available Controlled release urea (CRU has been widely adopted to increase nitrogen (N use efficiency and maize production, but the impacts can range widely depending on water availability in the soil. In an experiment using Zhengdan 958 (a popular summer maize hybrid, three levels of water treatments (adequate water condition [W3], which maintained soil moisture at about 75% ± 5% of the soil's field capacity; mild water stress [W2], which maintained moisture content at 55% ± 5% of field capacity; and severe water stress [W1], which had a moisture content of 35% ± 5% of field capacity and four levels of controlled release urea fertilizer (N0, N1, N2 and N3 were 0, 105, 210 and 315 kg N ha-1, respectively were compared in a rainout shelter system with soil. The results revealed that CRU had significant effects on maize yields and N use efficiencies under different water conditions. The mean yields increased with increasing water levels and showed significant differences. Under W1, the accumulation of dry matter and N were limited, and N internal efficiency (NIE and the apparent recovery efficiency of applied N (REN decreased with N increases; yields of N1, N2, and N3 were similar. Under W2, the dry matter and N accumulation, as well as the yield, showed an increasing trend with an increase in N application, and the NIE and REN of N3 showed no difference from N2. Under W3, yields of N2 and N3 were similar and they were significantly higher than that of N1, but the agronomic N use efficiency (ANUE, REN, and the physiological NUE (PNUE of N2 were 54.2, 34.9, and 14.4% higher, respectively, than those of N3. N application beyond the optimal N rate did not consistently increase maize yield, and caused a decrease in N use efficiencies. Highest overall dry matter, N accumulation, and yields were observed with N3 under W2, and those showed no differences with N2 and N3 under W3. Under this experimental condition, the CRU of 210 kg ha-1 was optimized when soil

Efficient water removal in lipase-catalyzed esterifications using a low-boiling-point azeotrope.

Science.gov (United States)

Yan, Youchun; Bornscheuer, Uwe T; Schmid, Rolf D

2002-04-05

High conversions in lipase-catalyzed syntheses of esters from free acyl donors and an alcohol requires efficient removal of water preferentially at temperatures compatible to enzyme activity. Using a lipase B from Candida antarctica (CAL-B)-mediated synthesis of sugar fatty-acid esters, we show that a mixture of ethyl methylketone (EMK) and hexane (best ratio: 4:1, vo/vo) allows efficient removal of water generated during esterification. Azeotropic distillation of the solvent mixture (composition: 26% EMK, 55% hexane, 19% water) takes place at 59 degrees C, which closely matches the optimum temperature reported for CAL-B. Water is then removed from the azeotrope by membrane vapor permeation. In case of glucose stearate, 93% yield was achieved after 48 h using an equimolar ratio of glucose and stearic acid. CAL-B could be reused for seven reaction cycles, with 86% residual activity after 14 d total reaction time at 59 degrees C. A decrease in fatty-acid chain length as well as increasing temperatures (75 degrees C) resulted in lower conversions. In addition, immobilization of CAL-B on a magnetic polypropylene carrier (EP 100) facilitated separation of the biocatalyst. Copyright 2002 Wiley Periodicals, Inc. Biotechnol Bioeng 78: 31--34, 2002; DOI 10.1002/bit.10084

Influence of water deficit on transpiration and radiation use efficiency of chickpea (Cicer arietinum L.)

International Nuclear Information System (INIS)

Singh, P.; Sri Rama, Y.V.

1989-01-01

Information on the relationship between biomass production, radiation use and water use of chickpea (Cicer arietinum L.) is essential to estimate biomass production in different water regimes. Experiments were conducted during three post-rainy seasons on a Vertisol (a typic pallustert) to study the effect of water deficits on radiation use, radiation use efficiency (RUE), transpiration and transpiration efficiency (TE) of chickpea. Different levels of soil water availability were created, either by having irrigated and non-irrigated plots or using a line source. Biomass production was linearly related to both cumulative intercepted solar radiation and transpiration in both well watered and water deficit treatments. Soil water availability did not affect RUE (total dry matter produced per unit of solar radiation interception) when at least 30% of extractable soil water (ESW) was present in the rooting zone, but below 30% ESW, RUE decreased linearly with the decrease in soil water content. RUE was also significantly correlated (R 2 = 0.61, P < 0.01) with the ratio of actual to potential transpiration (T/Tp) and it declined curvilinearly with the decrease in T/Tp. TE decreased with the increase in saturation deficit (SD) of air. Normalization of TE with SD gave a conservative value of 4.8 g kPa kg −1 . To estimate biomass production of chickpea in different environments, we need to account for the effect of plant water deficits on RUE in a radiation-based model and the effect of SD on TE in a transpiration-based model. (author)

Carbon Isotope discrimination in acacia auriculiformis - can it be used to select for higher water-use-efficiency in trees?

International Nuclear Information System (INIS)

Montagu, K.D.; Woo, K.C.; Puangchit, L.

1999-01-01

Full text: Determining the water-use-efficiency of trees in relation lo wood production is problematic due to the sheer size of the plant and the number of years taken to produce the wood. Indirect measures of water-use-efficiency, such as carbon isotope discrimination (Δ), are therefore attractive to tree breeders wishing to select for increased water-use-efficiency. To begin to evaluate the usefulness of Δ as a selection parameter for the tropical tree Acacia auriculiformis we addressed the following questions: 1. Within the tree canopy, how variable is Δ? 2. Is there any genotypic variation in Δ? and 3. Does water availability affect genotypic variation? To address these questions we sampled foliage from pot trials and field trials of A. auriculiformis ranging in age from 3 months lo 8 years in Australia and Thailand. In 16-18m high 8-year-old trees, canopy variation in Δ was large (P>0.01). Foliage Δ values increased down the tree from 22.0 %o at the top to 24.7 %o at the base. The decrease was rapid in the lop 3 m of the canopy thus considerable care must be taken to sampling foliage from the same position in the canopy. Genotype variations in Δ was observed in seedlings and 2 year-old trees (P>0.01) but not in 8 year-old trees (P=0.60). Where genotypic variation were observed the differences between the lowest and highest values were 2.2 - 3.6 %o. Reduced water availability decreased Δ values in both pot and field studies but not in a consistent way across seedlots. Thus it would appear that the Δ of trees grown under favourable conditions does not give an indication of the Δ value which will be obtained under water-limited conditions. This complicates the use of Δ as a screening method. We have clearly shown that genotype variation occurs in A. auriculiformis in both seedlings and young field-grown trees. Considerable care is required when sampling large trees, as variation in Δ within the tree can be as large as between genotypes. The challenge

Advances in Water Use Efficiency in Agriculture: A Bibliometric Analysis

Directory of Open Access Journals (Sweden)

Juan F. Velasco-Muñoz

2018-03-01

Full Text Available Water use efficiency in agriculture (WUEA has become a priority given increasing limitations on hydric resources. As a result, this area of research has increased in importance, becoming one of the most prolific lines of study. The main aim of this study was to present a review of worldwide WUEA research over the last 30 years. A bibliometric analysis was developed based on the Scopus database. The sample included 6063 articles. The variables analyzed were: articles per year, category, journal, country, institution, author, and keyword. The results indicate that a remarkable growth in the number of articles published per year is occurring. The main category is environmental science and the main journal Agricultural Water Management. The countries with the highest number of articles were China, the United States of America, and India. The institution that published the most articles was the Chinese Academy of Sciences and the authors from China also were the most productive. The most frequently used keywords were irrigation, crop yield, water supply, and crops. The findings of this study can assist researchers in this field by providing an overview of worldwide research.

Improving water use efficiency in drylands

NARCIS (Netherlands)

Stroosnijder, L.; Moore, D.; Alharbi, A.; Argaman, E.; Elsen, van den H.G.M.

2012-01-01

Drylands cover 41% of the global terrestrial area and 2 billion people use it for grazing and cropping. Food security is low owing to institutional and technical constraints. Absolute water scarcity and also the inability of crops to use available water are major technical issues. Significant

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

Systems analysis approach to the design of efficient water pricing policies under the EU water framework directive

DEFF Research Database (Denmark)

Riegels, Niels; Pulido-Velazquez, Manuel; Doulgeris, Charalampos

2013-01-01

management objectives. However, the design and implementation of economic instruments for water management, including water pricing, has emerged as a challenging aspect of WFD implementation. This study demonstrates the use of a systems analysis approach to designing and comparing two economic approaches......Economic theory suggests that water pricing can contribute to efficient management of water scarcity. The European Union (EU) Water Framework Directive (WFD) is a major legislative effort to introduce the use of economic instruments to encourage efficient water use and achieve environmental...... to efficient management of groundwater and surface water given EU WFD ecological flow requirements. Under the first approach, all wholesale water users in a river basin face the same volumetric price for water. This water price does not vary in space or in time, and surface water and groundwater are priced...

Virus removal efficiency of Cambodian ceramic pot water purifiers.

Science.gov (United States)

Salsali, Hamidreza; McBean, Edward; Brunsting, Joseph

2011-06-01

Virus removal efficiency is described for three types of silver-impregnated, ceramic water filters (CWFs) produced in Cambodia. The tests were completed using freshly scrubbed filters and de-ionized (DI) water as an evaluation of the removal efficiency of the virus in isolation with no other interacting water quality variables. Removal efficiencies between 0.21 and 0.45 log are evidenced, which is significantly lower than results obtained in testing of similar filters by other investigators utilizing surface or rain water and a less frequent cleaning regime. Other experiments generally found virus removal efficiencies greater than 1.0 log. This difference may be because of the association of viruses with suspended solids, and subsequent removal of these solids during filtration. Variability in virus removal efficiencies between pots of the same manufacturer, and observed flow rates outside the manufacturer's specifications, suggest tighter quality control and consistency may be needed during production.

Productivity, total and utilized nitrogen and water use efficiency of soybean grown in reclaimed sandy soil as affected by water regime

International Nuclear Information System (INIS)

Abdallah, A.A.G.; Thabet, E.M.A.

2002-01-01

Field experiment was performed at the experimental farm, Inshas, atomic energy authority, Egypt, in tafla and sand mixture soil (1:7). The experiment was laid out using sprinkler irrigation system with a line source which allows a gradual variation of irrigation from high to low irrigation, whereas the calculated amount of irrigation water levels were 1565, 1050 and 766.5 (m 3 / feddan). Two soybean varieties (crawford and giza 35) were planted. The obtained results indicated that: a) irrigation with high (1562 m 3 /fed.) and medium (1050 m 3 /fed.) water levels increased total seed wield of the two soybean varieties. b) the highest value of water use efficiency was observed when both soybean varieties irrigated with water level of 1050 m 3 /fed. c) seed protein content in crawford variety was higher in giza 35 variety at the irrigation level of 1562 m 3 /fed. d) seeds of both two soybean varieties showed increase of its atom excess percentage at high and medium water levels, and reflecting increase of nitrogen use efficiency. e) significant increment in seed yield kg/plot. Has been indicated by irrigation with water level of 1050 m 3 /fed. As compared to higher and lower water levels

A study of water pump efficiency for household water demand at Lubuklinggau

Science.gov (United States)

Emiliawati, Anna

2017-11-01

Water pump is a device to transport liquid from one place to another. This device is used in most of household in Indonesia. Small-scale water pump which is effective to lift more discharge is generally used. The ones that are most preferred are centrifugal types which having low absorbability. Pump performance is limited by pressure level in real electrical power whereas pump efficiency is influenced by head and discharge. The research aims to find out the efficiency of five distinct brands of home water pumps which are broadly distributed in market. Efficiency analysis take by laboratorium and financial analysis using NPV and BCR are done in order to obtained dicharge and pressure from each pump. At the end of the research, one out of 5 home water pump brands will be selected as the optimal working home water pump with low operational expense based on the utilizing age. The result of the research shows that the maximum efficiency value among various brands of water pump is diverse. Each value is arranged as follow from water pump A to E orderly: 12,9%, 13,5%, 12,8%, 14,8%, and 3,4%. From the calculation, water demand of South Lubuklinggau at stage 1 is 1117,7 l/s and stage 2 is 3495,2 l/s.. Moreover, the researcher conducts of investment, operation and maintenance cost with 25 years pump utilizing age towards 2 conditions (1) of maximum efficiency, i.e. pump A Rp16.563.971; pump B Rp12.163.798; pump C Rp11.809.513,2; pump D Rp11.473.928,3; pump E Rp12.648.708,3; (2) of max discharge, i.e. pump A Rp111.993.822,8; pump B Rp26.128.845,1; pump C Rp51.697.208,8; pump D Rp51.098.687,4; pump E Rp22.915.952,7;Financial analysis with interest rate 13% show a positive NPV(+) for all pump except pump A in max efficiency and a negative NPV (-) for all except pump B in max discharge. BCR value for max efficiency are pump A 0,8; pump B 1,6; pump C 1,7; pump D 1,7 and pump E 1,3. And for max discharge are pump A 0,2; pump B 1,1; pump C 0,7; pump D 0,7 and pump E 0,9. Result

Improving Agricultural Water Use Efficiency: A Quantitative Study of Zhangye City Using the Static CGE Model with a CES Water−Land Resources Account

Directory of Open Access Journals (Sweden)

Yu Liu

2017-02-01

Full Text Available Water resources play a vital role in human life and agriculture irrigation, especially for agriculture-dominant developing countries and regions. Improving agricultural water use efficiency has consequently become a key strategic choice. This study, based on Zhangye City’s economic characteristics and data, applies a static Computable General Equilibrium (CGE model with a constant elasticity of substitution (CES composited water−land resources account to assess the impact of improving agricultural water use efficiency on economy, water conservation and land reallocation. Results reveal that: Zhangye City’s GDP increases by 0.10% owing to an increasing average technical level by improving agricultural water use efficiency; total water consumption decreases by 122 million m3, 69% of which comes from a reduction of surface water use; and land demand increases by 257.43 hectares mainly due to agricultural land demands. With respect to the sectors’ output, export-oriented sectors with higher water intensities in the agricultural sectors benefit most. In contrast, land-intensive sectors contract the most, as the rental price of land rises. Therefore, agricultural water conservation technology should be introduced considering more in surface water. Furthermore, higher demand for agricultural land would reduce land availability for other sectors, thus inhibiting urbanization pace on a small scale.

Reduced irrigation increases the water use efficiency and productivity of winter wheat-summer maize rotation on the North China Plain.

Science.gov (United States)

Wang, Yunqi; Zhang, Yinghua; Zhang, Rui; Li, Jinpeng; Zhang, Meng; Zhou, Shunli; Wang, Zhimin

2018-03-15

The groundwater table has fallen sharply over the last 30years on the North China Plain, resulting in a shortage of water for winter wheat irrigation. Reducing irrigation may be an important strategy to maintain agricultural sustainability in the region; however, few studies have evaluated the transition from conventional irrigation management practices to reduced irrigation management practices in the winter wheat-summer maize rotation system. Here, we compare the yield, water consumption, and water use efficiency of winter wheat-summer maize rotation under conventional irrigation and reduced irrigation on the North China Plain from 2012 to 2015. Reducing irrigation decreased the yield but increased the water use efficiency and significantly advanced the harvest date of winter wheat. As a result, the summer maize sowing date advanced significantly, and the flowering date subsequently advanced 2-8days, thus extending the summer maize grain-filling stage. Therefore, the yield and water use efficiency of summer maize were higher under reduced irrigation than conventional irrigation, which compensated for the winter wheat yield loss under reduced irrigation. In addition, under reduced irrigation from 2012 to 2015, the yield and water use efficiency advantage of the winter wheat-summer maize rotation ranged from 0.0 to 9.7% and from 4.1 to 14.7%, respectively, and water consumption and irrigated water decreased by 20-61mm and 150mm, respectively, compared to conventional irrigation. Overall, the reduced irrigation management practice involving no irrigation after sowing winter wheat, and sowing summer maize on June 7 produced the most favorable grain yield with superb water use efficiency in the winter wheat-summer maize rotation. This study indicates that reducing irrigation could be an efficient means to cope with water resource shortages while maintaining crop production sustainability on the North China Plain. Copyright © 2017. Published by Elsevier B.V.

[Experimental study on crop photosynthesis, transpiration and high efficient water use].

Science.gov (United States)

Wang, Huixiao; Liu, Changming

2003-10-01

It is well known that the development of water-saving agriculture is a strategic choice for getting rid of the crisis of water shortage. In this paper, the crop photosynthesis, transpiration, stomatic behavior, and their affecting factors were studied in view of increasing the crop water use efficiency. The experimental results showed that there was a parabola relationship between photosynthesis and transpiration. The transpiration at the maximum photosynthesis was a critical value, above which, transpiration was the luxurious part. The luxurious transpiration could be controlled without affecting photosynthetic production. It is possible that the measures for increasing stomatic resistance and preventing transpiration could save water, and improve photosynthesis and yield as well. The photosynthesis rate increased with photosynthetic active radiation, and the light saturation point for photosynthesis existed. The light saturation point of dry treatment was much lower than that of wet treatment, and the relationship between transpiration and radiation was linear. When the photosynthetic active radiation was bigger than 1,000 mumol.m-2.s-1, some treatments could be carried out for decreasing transpiration and improving photosynthesis.

Ozone decreases soybean productivity and water use efficiency

Science.gov (United States)

Betzelberger, A. M.; VanLoocke, A. D.; Ainsworth, E. A.; Bernacchi, C. J.

2011-12-01

The combination of population growth and climate change will increase pressure on agricultural and water resources throughout this century. An additional consequence of this growth is an increase in anthropogenic emissions that lead to the formation of tropospheric ozone (O3), which in concert with climate change, poses a significant threat to human health and nutrition. In addition to being an important greenhouse gas, O3 reduces plant productivity, an effect that has been particularly pronounced in soybean, which provides over half of the world's oilseed production. Plant productivity is linked to feedbacks in the climate system, indirectly through the carbon cycle, as well as directly through the partitioning of radiation into heat and moisture fluxes. Soybean, along with maize, comprises the largest ecosystem in the contiguous U.S. Therefore, changes in productivity and water use under increasing O3 could impact human nutrition as well as the regional climate. Soybean response to increasing O3 concentrations was tested under open-air agricultural conditions at the SoyFACE research site. During the 2009 growing season, eight 20 m diameter FACE plots were exposed to different O3 concentrations, ranging from 40 to 200 ppb. Canopy growth (leaf area index) and physiological measurements of leaf photosynthesis and stomatal conductance were taken regularly throughout the growing season. Canopy fluxes of heat and moisture were measured using the residual energy balance micrometeorological technique. Our results indicate that as O3 increased from 40 to 200 ppb, rates of photosynthesis and stomatal conductance decreased significantly. Further, the seed yield decreased by over 60%, while water use decreased by 30% and the water-use-efficiency (yield/water-use) declined by 50%. The growing season average canopy temperatures increased by 1°C and midday temperatures increased by 2°C compared to the control. Warmer and drier canopies may result in a positive feedback on O3

Effects of Watering and Nitrogen Fertilization on Yield and Water and Nitrogen Use Efficiency of Cropping Oil Sunflower

Directory of Open Access Journals (Sweden)

TAN Jian-xin

2015-10-01

Full Text Available The field experiment with split-plot design was conducted to study the effects of the interaction of water and nitrogen fertilization on the growth and yield of oil sunflower, water and nitrogen use efficiency of cropping oil sunflower. This experiment set three irrigation rate treatments, including high irrigation treatment (5 250 m3·hm-2, middle irrigation treatment (3 750 m3·hm-2, low irrigation treatment (2 250 m3·hm-2, and four nitrogen application rate treatments, covering no nitrogen fertilization treatment (0 kg·hm-2, low nitrogen application treatment (120 kg·hm-2, middle nitrogen application treatment (240 kg·hm-2 and high nitrogen application treatment (360 kg·hm-2. The results showed that the nitrogen absorption and nitrogen use efficiency of cropping oil sunflower increased as the irrigation rate increased. With the nitrogen application rate increased, the yield of cropping oil sunflower was increased when the nitrogen application rate was 0~240 kg·hm-2, but beyond the 240 kg·hm-2, there was no significant increase. With the irrigation rate increased, the water consumption amount of cropping oil sunflower increased all the time, but the water use efficiency increased first, and hen decreased. Besides there was no significant difference between 240 kg·hm-2 and 360 kg·hm-2 treatment. Under our experiment condition, during the cropping oil sunflower growth period, when the irrigation rate was 5 250 m3·hm-2 (high irrigation rate and the nitrogen ertilization was 360 m3·hm-2 (high nitrogen application rate, the yield of cropping oil sunflower was 3 598 kg·hm-2. When the irrigation rate was 3 750 m3·hm-2 (middle irrigation rate and the nitrogen fertilization was 240 m3·hm-2 (middle nitrogen application rate, the yield was 3 518 kg·hm-2, with the yield components similar with the high irrigation rate and high nitrogen application rate treatment. Considering various factors, middle irrigation rate and middle nitrogen

Isotope and radiation techniques for efficient water and fertilizer use in semi-arid regions

International Nuclear Information System (INIS)

1986-04-01

The Joint FAO/IAEA Division carried out a coordinated research programme, which was concerned with the efficiency of water and fertilizer uses in semi-arid farming systems. The present publication is a summary of the individual contributions from Belgium, Chile, Ivory Coast, Cyprus, France, India, Israel, Romania, Senegal, Sri Lanka and the United States of America, over the period 1978-1984. Water and fertilizer uptake by crops are dynamic processes affected by several factors of the soil-plant-atmosphere system. The neutron moisture meters were used not only to measure soil water contents but also to understand water dynamics under field conditions. Nitrogen is the most limiting nutrient in many semi-arid regions, and as its absorption is very much related to water dynamics in the soil, experiments using N-15 labelled fertilizer were carried out, which are presented in this report

LOW WATER DEMAND CEMENTS - WAY OF EFFICIENT USE OF CLINKER AND MINERAL FILLERS IN CONCRETES

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Khokhryakov Oleg Viktorovich

2017-10-01

Full Text Available Subject: the provisions in the updated edition of the technical specifications for cements are analyzed. A trend to decrease the clinker volume in Portland cement due to the wider use of mineral additives, up to 95%, was observed. Research objectives: substantiation of the most complete and efficient use of Portland cement and mineral additives in the composition of low water demand cements. Materials and methods: portland cement, mineral additives and superplasticizer were used as raw materials for obtaining cements of low water demand. The experimental methods comply with the current standards. Results: comparative properties of low water demand cements and cements with mineral additives are presented. The properties of cement-water suspensions of these binders have been studied, and, on their basis, heavy concretes have been made. The results of the grindability of Portland cement and mineral components with a superplasticizer are given. Conclusions: it is shown that the cement of low water demand, in which the advantages of both Portland cement and mineral additives are more fully and efficiently presented, complies with the tendency to decrease the clinker volume to the greatest degree. It is established that the clinker volume index for heavy concrete prepared on low water demand cement is almost four times lower than that for heavy concrete based on common Portland cement.

Greater efficiency of water use in poplar clones having a delayed response of mesophyll conductance to drought.

Science.gov (United States)

Théroux Rancourt, Guillaume; Éthier, Gilbert; Pepin, Steeve

2015-02-01

Improvement of water use efficiency is a key objective to improve the sustainability of cultivated plants, especially fast growing species with high water consumption like poplar. It is well known that water use efficiency (WUE) varies considerably among poplar genotypes, and it was recently suggested that the use of the mesophyll-to-stomatal conductance ratio (gm/gs) would be an appropriate trait to improve WUE. The responses of 7-week-old cuttings of four hybrid poplar clones and one native Balsam poplar (Populus balsamifera L.) to a water stress-recovery cycle were examined to evaluate the relation between the gm/gs ratio and transpiration efficiency (TE), a leaf-level component of WUE. A contrasting gs response to water stress was observed among the five clones, from stomatal closure early on during soil drying up to limited closure in Balsam poplar. However in the hybrids, the decline in gm was consistently delayed by a few days compared with gs. Moreover, in the most water use-efficient hybrids, the recovery following rehydration occurred faster for gm than for gs. Thus, the delay in the response of gm to drought and its faster recovery upon rewatering increased the gm/gs of the hybrids and this ratio scaled positively with TE. Our results support the use of the gm/gs ratio to select genotypes with improved WUE, and the notion that breeding strategies focusing mainly on stomatal responses to soil drying should also look for a strong curvilinearity between net carbon assimilation rate and gs, the indication of a significant increase in gm/gs in the earlier stages of stomatal closure. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Validation of AquaCrop Model for Simulation of Winter Wheat Yield and Water Use Efficiency under Simultaneous Salinity and Water Stress

OpenAIRE

M. Mohammadi; B. Ghahraman; K. Davary; H. Ansari; A. Shahidi

2016-01-01

Introduction: FAO AquaCrop model (Raes et al., 2009a; Steduto et al., 2009) is a user-friendly and practitioner oriented type of model, because it maintains an optimal balance between accuracy, robustness, and simplicity; and it requires a relatively small number of model input parameters. The FAO AquaCrop model predicts crop productivity, water requirement, and water use efficiency under water-limiting and saline water conditions. This model has been tested and validated for different crops ...

Identification of durum wheat genotypes with efficiency on the uptake and Use of water using Carbon-13 discrimination and neutron moisture meter

International Nuclear Information System (INIS)

Mechergui, M.; Daaloul, A.; Snane, M.H.

1995-01-01

Carbon-13 isotope discrimination method and water balance model Using neutron probe are the two tools used in this study to genotypes for water use efficiency. It is a three years experiment and the results presented will be for the last year. Four durum wheat Cvs were selected and planted in a randomnized block design with 6 replicates. Total consumption of water was calculated. Grain and strow yields and other parameters were recorded. The carbon isotope ratio which illustrates carbon 13 dicrimination is measured for each genotype in grain and strow. The total and the grain water use efficiency were calculated and correlated to the G C-13 isotope dicrimination to compare genotypes between them. The main results presented in this paper revealed that. Carbon-13 discrimination technique is an excellent screening technique for screening for water use in cultivars in semi-arid conditions. 2 fig., 3 tabs

Identification of durum wheat genotypes with efficiency on the uptake and Use of water using Carbon-13 discrimination and neutron moisture meter

Energy Technology Data Exchange (ETDEWEB)

Mechergui, M; Daaloul, A [Institut National Agronomique de Tunisie, 43, Avenue Charles Nicolle - 1082 Tunis Mahrajene - (Tunisia); Snane, M H [Institut National Agronomique de (Tunisia)

1995-10-01

Carbon-13 isotope discrimination method and water balance model Using neutron probe are the two tools used in this study to genotypes for water use efficiency. It is a three years experiment and the results presented will be for the last year. Four durum wheat Cvs were selected and planted in a randomnized block design with 6 replicates. Total consumption of water was calculated. Grain and strow yields and other parameters were recorded. The carbon isotope ratio which illustrates carbon 13 dicrimination is measured for each genotype in grain and strow. The total and the grain water use efficiency were calculated and correlated to the G C-13 isotope dicrimination to compare genotypes between them. The main results presented in this paper revealed that. Carbon-13 discrimination technique is an excellent screening technique for screening for water use in cultivars in semi-arid conditions. 2 fig., 3 tabs.

Carbon isotope discrimination as a selection tool for high water use efficiency and high crop yields

International Nuclear Information System (INIS)

Kumarasinghe, K.S.; Kirda, C.; Bowen, G.D.; Zapata, F.; Awonaike, K.O.; Holmgren, E.; Arslan, A.; De Bisbal, E.C.; Mohamed, A.R.A.G.; Montenegro, A.

1996-01-01

Results of back-up research conducted at the FAO/IAEA Agriculture and Biotechnology Laboratory in support of the FAO/IAEA Co-ordinated Research Programme on the Use of Isotope Studies on Increasing and Stabilizing Plant Productivity in Low Phosphate and Semi-arid and Sub-humid Soils of the Tropics and Sub-tropics, are presented here. Neutron probe measurements confirmed the earlier reports of a strong correlation of Δ with grain yield and water use efficiency of wheat. High soil gypsum content and soil salinity, a wide spread problem in soils of arid and semi-arid climatic zones, do not interfere with the association of Δ with crop yields, provided plants are grown in similar soil water status and soil fertility level. Results of a glasshouse experiment using selected cowpea genotypes showed that Δ values measured at flowering stage positively correlated with total dry matter production and percent N 2 derived from atmosphere (%Ndfa), contributing to an earlier report from the laboratory that it may be possible to use Δ values for screening of leguminous crops for high N 2 fixation potential. 13 C isotope discrimination in the leaves of Gliricidia sepium was measured to examine if the technique could be extended to studies with trees. Results of a glasshouse experiment with 18 provenances of Gliricidia sepium showed highly significant correlations of Δ with total dry matter production, water use efficiency and total N accumulated through biological nitrogen fixation. Although the correlation of Δ with water use efficiency and dry matter yield are relatively clear and better understood, the correlation with nitrogen fixation still needs a closer examination under different environmental conditions and with different species. While 13 C isotope discrimination may be a valuable tool for identifying annual crops with high water use efficiency and high yield potential, it may be more attractive for tree species considering the long growth periods taken for trees

ISSUES ON THE ROLE OF EFFICIENT WATER PRICING FOR SUSTAINABLE WATER MANAGEMENT

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Simona FRONE

2012-06-01

Full Text Available This paper aims to highlight some of the main issues raised by developing and implementing the most appropriate approach to water pricing, and to induce a sustainable water management. Therefore, we define the concept and utility of water demand management as one objective of efficient water pricing. Next we analyse the basic economics and some important theoretical insights of water pricing. We further with state the main four inter-correlated principles of sustainable water pricing (full-cost recovery, economic efficiency,equity and administrative feasability and the trends and challenges of their actual implementing in the water pricing policy of Romania and other EU countries. We end with a review of opinions, personal conclusions and recommendations on the actual opportunity, effectiveness and role of efficient water pricing in fulfilling the goals of sustainabilty.

Possibilities for the efficient utilisation of spent geothermal waters.

Science.gov (United States)

Tomaszewska, Barbara; Szczepański, Andrzej

2014-10-01

Waters located at greater depths usually exhibit high mineral content, which necessitates the use of closed systems, i.e. re-injecting them into the formation after recovering the heat. This significantly reduces investment efficiency owing to the need to drill absorption wells and to perform anti-corrosion and anti-clogging procedures. In this paper, possibilities for the efficient utilisation of cooled geothermal waters are considered, particularly with respect to open or mixed geothermal water installations. Where cooled water desalination technologies are used, this allows the water to be demineralised and used to meet local needs (as drinking water and for leisure purposes). The retentate left as a by-product of the process contains valuable ingredients that can be used for balneological and/or leisure purposes. Thus, the technology for desalinating spent geothermal waters with high mineral content allows improved water management on a local scale and makes it possible to minimise the environmental threat resulting from the need to dump these waters into waterways or surface water bodies and/or inject them into the formation. The paper is concerned with Polish geothermal system and provides information about the parameters of Polish geothermal waters.

Effect of Timing and Amount of Irrigation Water on Bean Yield and Water Use Efficiency in Arid and Semi-arid Conditions

Directory of Open Access Journals (Sweden)

S.S. Nurbakhsh

2016-02-01

Full Text Available Introduction: Nowadays, due to lack of water resources and increasing demand for water, agricultural water planning issues need further consideration. With proper planning and determination of irrigation depth and time, the effects of stress and yield loss on the plants are reduced. Irrigation scheduling is one of the most important factors in crop’s quality and quantity. The main objective of irrigation scheduling is to control crop’s water conditions in order to achieve its optimum yield level. So irrigation timing is the vital factor on which crop water stress and eventually yield's level are dependent upon. Moreover, irrigation timing is used in irrigation scheduling. The aim of this study was to evaluate the effect of irrigation time on water consumption, water use efficiency and yield of beans. Materials and Methods: In order to observe the effect of the amount and the time of the irrigation on water consumption, yields rate and water use efficiency, the current research was carried out at the University of Shahrekord during the summer of 2012. The experiment was done as a completely randomized design with 4 repetitions consisting of irrigation time and the amount of irrigation in 4 and 2 levels (at 6, 8, 14 and 18 and (deficit irrigation, full irrigation, respectively. Beans seeds were planted in 32 similar vases with a diameter of 45 cm and height of 60 cm, in each experiment. Treatments were begun after 37 days from planting. Treatments were irrigated when the average moisture in the root zone was equal to the lower border of readily available water of full irrigation. At the end of the experiments, plants were completely harvested. Then the plant’s height, number of branches, numbers of pods per plant, pod and seed weight were measured. Results and Discussion: Results showed that irrigating at different times during the day influenced water use efficiency, water consumption, seeds yield and number of pods in the bush. The water

Effect of water stress on growth, yield and water use efficiency of berseem (Trifolium alexandrium in Tadla

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B. Bouazzama

2018-01-01

Full Text Available The study of crop response to water deficit is important in areas where water resources are limited. This study was carried out over the period 2008-2011 in order to study the effect of water deficit on the productivity of berseem in the Tadla region. Four water regimes (100%, 80%, 60% and 40% ETc were compared under both flood and drip irrigation techniques. Observations were made on the soil, biomass at each cut and root system. The results showed that the average annual maximum yield obtained was 16.2 t/ha. Reductions in yields by applying 60% of water inputs are 40% and 42% in 2009/10 and 2010/11, respectively. The contribution of cycles without irrigation to annual biomass yield varies from 35% under 100% ETc to 52% under 40% ETc. Water use efficiency of berseem over the over the entire crop period is 3.37 kg/m3. The maximum average yield obtained under drip irrigation was 15.7 t/ha. It was obtained with a water supply of 411 mm which allowed a saving of 57% of water supply versus flood irrigation technique.

The effect of strobilurins on leaf gas exchange, water use efficiency and ABA content in grapevine under field conditions.

Science.gov (United States)

Diaz-Espejo, Antonio; Cuevas, María Victoria; Ribas-Carbo, Miquel; Flexas, Jaume; Martorell, Sebastian; Fernández, José Enrique

2012-03-01

Strobilurins are one of the most important classes of agricultural fungicides. In addition to their anti-fungal effect, strobilurins have been reported to produce simultaneous effects in plant physiology. This study investigated whether the use of strobilurin fungicide improved water use efficiency in leaves of grapevines grown under field conditions in a Mediterranean climate in southern Spain. Fungicide was applied three times in the vineyard and measurements of leaf gas exchange, plant water status, abscisic acid concentration in sap ([ABA]), and carbon isotope composition in leaves were performed before and after applications. No clear effect on stomatal conductance, leaf water potential and intrinsic water use efficiency was found after three fungicide applications. ABA concentration was observed to increase after fungicide application on the first day, vanishing three days later. Despite this transient effect, evolution of [ABA] matched well with the evolution of leaf carbon isotope ratio, which can be used as a surrogate for plant water use efficiency. Morning stomatal conductance was negatively correlated to [ABA]. Yield was enhanced in strobilurin treated plants, whereas fruit quality remained unaltered. Published by Elsevier GmbH.

Impacts of multiple global environmental changes on African crop yield and water use efficiency: Implications to food and water security

Science.gov (United States)

Pan, S.; Yang, J.; Zhang, J.; Xu, R.; Dangal, S. R. S.; Zhang, B.; Tian, H.

2016-12-01

Africa is one of the most vulnerable regions in the world to climate change and climate variability. Much concern has been raised about the impacts of climate and other environmental factors on water resource and food security through the climate-water-food nexus. Understanding the responses of crop yield and water use efficiency to environmental changes is particularly important because Africa is well known for widespread poverty, slow economic growth and agricultural systems particularly sensitive to frequent and persistent droughts. However, the lack of integrated understanding has limited our ability to quantify and predict the potential of Africa's agricultural sustainability and freshwater supply, and to better manage the system for meeting an increasing food demand in a way that is socially and environmentally or ecologically sustainable. By using the Dynamic Land Ecosystem Model (DLEM-AG2) driven by spatially-explicit information on land use, climate and other environmental changes, we have assessed the spatial and temporal patterns of crop yield, evapotranspiration (ET) and water use efficiency across entire Africa in the past 35 years (1980-2015) and the rest of the 21st century (2016-2099). Our preliminary results indicate that African crop yield in the past three decades shows an increasing trend primarily due to cropland expansion (about 50%), elevated atmospheric CO2 concentration, and nitrogen deposition. However, crop yield shows substantially spatial and temporal variation due to inter-annual and inter-decadal climate variability and spatial heterogeneity of environmental drivers. Climate extremes especially droughts and heat wave have largely reduced crop yield in the most vulnerable regions. Our results indicate that N fertilizer could be a major driver to improve food security in Africa. Future climate warming could reduce crop yield and shift cropland distribution. Our study further suggests that improving water use efficiency through land

Can a canopy temperature-based stress index enhance water use efficiency in irrigated wine grape under arid conditions?

Science.gov (United States)

Enhancement of irrigation water use efficiency and water productivity in arid wine grape production regions is hindered by a lack of automated, real-time methods for monitoring and interpreting vine water status. A normalized, water stress index calculated from real-time vine canopy temperature meas...

Can diversity in root architecture explain plant water use efficiency? A modeling study.

Science.gov (United States)

Tron, Stefania; Bodner, Gernot; Laio, Francesco; Ridolfi, Luca; Leitner, Daniel

2015-09-24

Drought stress is a dominant constraint to crop production. Breeding crops with adapted root systems for effective uptake of water represents a novel strategy to increase crop drought resistance. Due to complex interaction between root traits and high diversity of hydrological conditions, modeling provides important information for trait based selection. In this work we use a root architecture model combined with a soil-hydrological model to analyze whether there is a root system ideotype of general adaptation to drought or water uptake efficiency of root systems is a function of specific hydrological conditions. This was done by modeling transpiration of 48 root architectures in 16 drought scenarios with distinct soil textures, rainfall distributions, and initial soil moisture availability. We find that the efficiency in water uptake of root architecture is strictly dependent on the hydrological scenario. Even dense and deep root systems are not superior in water uptake under all hydrological scenarios. Our results demonstrate that mere architectural description is insufficient to find root systems of optimum functionality. We find that in environments with sufficient rainfall before the growing season, root depth represents the key trait for the exploration of stored water, especially in fine soils. Root density, instead, especially near the soil surface, becomes the most relevant trait for exploiting soil moisture when plant water supply is mainly provided by rainfall events during the root system development. We therefore concluded that trait based root breeding has to consider root systems with specific adaptation to the hydrology of the target environment.

Effect of Drought Stress on Water Use Efficiency and Its Components in Several Genotypes and Cultivars of Foxtail Millet (Setaria italica L.

Directory of Open Access Journals (Sweden)

M Khazaei

2018-05-01

Full Text Available Introduction According to NASA reports about atmospheric earth conditions, in the 30 years later, 45 countries will face with severe droughts and Iran is in the fourth place in this list. Water shortage is one of the most important limiting factors of production that affects plants growth by changing physiological conditions. Using adapted plants is a proper strategy to deal with the effects of water shortage on the status of water restrictions. Foxtail millet is a C4 plant with good compatibility to dry areas and it has high water use efficiency. In medium stress partial stomata closure reduces transpiration more than photosynthesis in this plant and as a result, increase water use efficiency. Materials and Methods This experiment was carried out as split-plot layout based on randomized complete blocks design with four replications at the Agricultural Research Station, University of Birjand in 2014-2015. The main factor was drought stress in three levels including 100, 75 and 50 percent of plant water requirement (no stress as control, moderate stress and severe stress, respectively and the sub-factor was millet genotype in three levels (including Bastan, KFM5 and KFM20. At four leaf stage, 75 plants per square meter were maintained and applied stress. Water use efficiency, evapotranspiration efficiency, harvest index for seed and ear, economic and biological yield were measured at maturity. . Data were analyzed with the SAS software ver 9.1 and the means were compared with Tukey’s test. Results and Discussion The results showed that water use efficiency (WUE was significantly decreased with increasing the intensity of drought stress in all three genotypes but not evapotranspiration efficiency (ETE, ratio of total dry matter to water used. Bastan cultivar had higher water use efficiency in all stress levels and was more affected under moderate stress while it was less affected under severe stress (33 and 31 percent compared to the control

Photosynthesis and chloroplast genes are involved in water-use efficiency in common bean.

Science.gov (United States)

Ruiz-Nieto, Jorge E; Aguirre-Mancilla, César L; Acosta-Gallegos, Jorge A; Raya-Pérez, Juan C; Piedra-Ibarra, Elías; Vázquez-Medrano, Josefina; Montero-Tavera, Victor

2015-01-01

A recent proposal to mitigate the effects of climatic change and reduce water consumption in agriculture is to develop cultivars with high water-use efficiency. The aims of this study were to characterize this trait as a differential response mechanism to water-limitation in two bean cultivars contrasting in their water stress tolerance, to isolate and identify gene fragments related to this response in a model cultivar, as well as to evaluate transcription levels of genes previously identified. Keeping CO2 assimilation through a high photosynthesis rate under limited conditions was the physiological response which allowed the cultivar model to maintain its growth and seed production with less water. Chloroplast genes stood out among identified genetic elements, which confirmed the importance of photosynthesis in such response. ndhK, rpoC2, rps19, rrn16, ycf1 and ycf2 genes were expressed only in response to limited water availability. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

Impact of Irrigation Method on Water Use Efficiency and Productivity of Fodder Crops in Nepal

Directory of Open Access Journals (Sweden)

Ajay K Jha

2016-01-01

Full Text Available Improved irrigation use efficiency is an important tool for intensifying and diversifying agriculture in Nepal, resulting in higher economic yield from irrigated farmlands with a minimum input of water. Research was conducted to evaluate the effect of irrigation method (furrow vs. drip on the productivity of nutritious fodder species during off-monsoon dry periods in different elevation zones of central Nepal. A split-block factorial design was used. The factors considered were treatment location, fodder crop, and irrigation method. Commonly used local agronomical practices were followed in all respects except irrigation method. Results revealed that location effect was significant (p < 0.01 with highest fodder productivity seen for the middle elevation site, Syangja. Species effects were also significant, with teosinte (Euchlaena mexicana having higher yield than cowpea (Vigna unguiculata. Irrigation method impacted green biomass yield (higher with furrow irrigation but both methods yielded similar dry biomass, while water use was 73% less under drip irrigation. Our findings indicated that the controlled application of water through drip irrigation is able to produce acceptable yields of nutritionally dense fodder species during dry seasons, leading to more effective utilization and resource conservation of available land, fertilizer and water. Higher productivity of these nutritional fodders resulted in higher milk productivity for livestock smallholders. The ability to grow fodder crops year-round in lowland and hill regions of Nepal with limited water storages using low-cost, water-efficient drip irrigation may greatly increase livestock productivity and, hence, the economic security of smallholder farmers.

Guidelines to Develop Efficient Photocatalysts for Water Splitting

KAUST Repository

Garcia Esparza, Angel T.

2016-04-03

Photocatalytic overall water splitting is the only viable solar-to-fuel conversion technology. The research discloses an investigation process wherein by dissecting the photocatalytic water splitting device, electrocatalysts, and semiconductor photocatalysts can be independently studied, developed and optimized. The assumption of perfect catalysts leads to the realization that semiconductors are the limiting factor in photocatalysis. This dissertation presents a guideline for efficient photocatalysis using semiconductor particles developed from idealized theoretical simulations. No perfect catalysts exist; then the discussion focus on the development of efficient non-noble metal electrocatalysts for hydrogen evolution from water reduction. Tungsten carbide (WC) is selective for the catalysis of hydrogen without the introduction of the reverse reaction of water formation, which is critical to achieving photocatalytic overall water splitting as demonstrated in this work. Finally, photoelectrochemistry is used to characterize thoroughly Cu-based p-type semiconductors with potential for large-scale manufacture. Artificial photosynthesis may be achieved by following the recommendations herein presented.

Removal efficiency of water purifier and adsorbent for iodine, cesium, strontium, barium and zirconium in drinking water.

Science.gov (United States)

Sato, Itaru; Kudo, Hiroaki; Tsuda, Shuji

2011-01-01

The severe incident of Fukushima Daiichi Nuclear Power Station has caused radioactive contamination of environment including drinking water. Radioactive iodine, cesium, strontium, barium and zirconium are hazardous fission products because of the high yield and/or relatively long half-life. In the present study, 4 pot-type water purifiers and several adsorbents were examined for the removal effects on these elements from drinking water. Iodide, iodate, cesium and barium were removed by all water purifiers with efficiencies about 85%, 40%, 75-90% and higher than 85%, respectively. These efficiencies lasted for 200 l, which is near the recommended limits for use of filter cartridges, without decay. Strontium was removed with initial efficiencies from 70% to 100%, but the efficiencies were slightly decreased by use. Zirconium was removed by two models, but hardly removed by the other models. Synthetic zeolite A4 efficiently removed cesium, strontium and barium, but had no effect on iodine and zirconium. Natural zeolite, mordenite, removed cesium with an efficiency as high as zeolite A4, but the removal efficiencies for strontium and barium were far less than those of zeolite A4. Activated carbon had little removal effects on these elements. In case of radioactive contamination of tap water, water purifiers may be available for convenient decontamination of drinking water in the home.

Physiological factors affecting intrinsic water use efficiency of potato clones within a dihaploid mapping population under well-watered and drought-stressed conditions

DEFF Research Database (Denmark)

Topbjerg, Henrik Bak; Kaminski, Kacper Piotr; Markussen, Bo

2014-01-01

) within a dihaploid potato (Solanum tuberosum L.) mapping population under well-watered (WW) and drought-stress (DS) conditions. The factorial dependency of WUEi on several plant bio-physiological traits was analyzed, and clonal difference of WUEi was compared. Significant differences in WUEi were found......Optimizing crops water use is essential for ensuring food production under future climate scenarios. Therefore, new cultivars that are capable of maintaining production under limited water resource are needed. This study screened for clonal differences in intrinsic water use efficiency (WUEi...

Water use efficiency in potatoes crop using nuclear techniques in Tumbaco - Ecuador

International Nuclear Information System (INIS)

Calvache, Marcelo; Ontaneda, Milton; Flor Jorge.

1986-01-01

The optimum water layer for potatoes (Solanum tuberosum L.) was computed by the balance of mass method. This project was carried out in a Typic Ustropepts, Silty-Loam Soil at 'La Tola' Experimental Field. Soil humidity was determined through the neutron probe. Irrigation efficiency for the first application layer, - layer 3- (30 days old crop), was 17%. It was increased to 34% at the age of 100 days. Layer 2 was increased to 25% and layer 1 to 20%. By this time the crop was developed. Crop water consumptive usage at layer 3 was 476.4 mm; 355.7 mm in layer 2; 390.5 mm for layer 1 and 269.3 mm in layer 0. Yield production was of the 29. 24.; 18.4 and 15. Kg/ha respectively. It is concluded that the timely application of water to potato crops is very important

Urban water metabolism efficiency assessment: integrated analysis of available and virtual water.

Science.gov (United States)

Huang, Chu-Long; Vause, Jonathan; Ma, Hwong-Wen; Yu, Chang-Ping

2013-05-01

Resolving the complex environmental problems of water pollution and shortage which occur during urbanization requires the systematic assessment of urban water metabolism efficiency (WME). While previous research has tended to focus on either available or virtual water metabolism, here we argue that the systematic problems arising during urbanization require an integrated assessment of available and virtual WME, using an indicator system based on material flow analysis (MFA) results. Future research should focus on the following areas: 1) analysis of available and virtual water flow patterns and processes through urban districts in different urbanization phases in years with varying amounts of rainfall, and their environmental effects; 2) based on the optimization of social, economic and environmental benefits, establishment of an indicator system for urban WME assessment using MFA results; 3) integrated assessment of available and virtual WME in districts with different urbanization levels, to facilitate study of the interactions between the natural and social water cycles; 4) analysis of mechanisms driving differences in WME between districts with different urbanization levels, and the selection of dominant social and economic driving indicators, especially those impacting water resource consumption. Combinations of these driving indicators could then be used to design efficient water resource metabolism solutions, and integrated management policies for reduced water consumption. Copyright © 2013 Elsevier B.V. All rights reserved.

Drainage estimation to aquifer and water use irrigation efficiency in semi-arid zone for a long period of time

Science.gov (United States)

Jiménez-Martínez, J.; Molinero-Huguet, J.; Candela, L.

2009-04-01

Water requirements for different crop types according to soil type and climate conditions play not only an important role in agricultural efficiency production, though also for water resources management and control of pollutants in drainage water. The key issue to attain these objectives is the irrigation efficiency. Application of computer codes for irrigation simulation constitutes a fast and inexpensive approach to study optimal agricultural management practices. To simulate daily water balance in the soil, vadose zone and aquifer the VisualBALAN V. 2.0 code was applied to an experimental area under irrigation characterized by its aridity. The test was carried out in three experimental plots for annual row crops (lettuce and melon), perennial vegetables (artichoke), and fruit trees (citrus) under common agricultural practices in open air for October 1999-September 2008. Drip irrigation was applied to crops production due to the scarcity of water resources and the need for water conservation. Water level change was monitored in the top unconfined aquifer for each experimental plot. Results of water balance modelling show a good agreement between observed and estimated water level values. For the study period, mean drainage obtained values were 343 mm, 261 mm and 205 mm for lettuce and melon, artichoke and citrus respectively. Assessment of water use efficiency was based on the IE indicator proposed by the ASCE Task Committee. For the modelled period, water use efficiency was estimated as 73, 71 and 78 % of the applied dose (irrigation + precipitation) for lettuce and melon, artichoke and citrus, respectively.

Increasing hydro turbine operation range and efficiencies using water injection in draft tubes

Energy Technology Data Exchange (ETDEWEB)

Francke, Haakon Hjort

2010-09-15

It is a well known fact that most Francis turbines, because of the fixed blade design, faces challenges when running at partial load operation. Especially in the operating range below approximately 50 % of the rated output, it is common to observe severe pressure pulsations and surge in the draft tube. These pressure fluctuations are believed to be related to the swirling flow exiting the runner. By using water jets in the draft tube cone directed towards the swirling flow, the swirl strength is believed to be reduced and thereby also the pressure fluctuations produced by the swirl. This system thus has a potential of increasing the turbine operating range. The system can be activated when needed, and will not affect the turbine when running at its best efficiency point.Based on the main hypothesis, a simplified swirl rig was designed and constructed in order to investigate the nozzle influence on the swirling flow and on the pressure pulsations in a simplified environment. To expand the understanding of the nozzle performance in a Francis turbine, experiments were conducted in a model turbine with a prototype of movable nozzles. To establish a link between laboratory nozzle measurements and full scale nozzle measurements, field measurements were carried out on full scale Francis turbines running at partial discharge. For this purpose the turbines installed at Skarsfjord Power Station and Skibotn Power Station were used, where full scale nozzle injection systems were installed. The test results suggested that the concept of water injection worked, but not unconditionally. A reduction in pressure fluctuations was achieved both in laboratory and field experiments, as well as a noticeable reduction regarding fluctuations in the shaft run-out at Skibotn. In addition, water injection gave a surprisingly positive effect at overload conditions in the model turbine, even though the nozzle angle was directed in the same direction as the overload swirl. Ideally, the results

Response of water deficit regime and soil amelioration on evapotranspiration loss and water use efficiency of maize ( Zea mays l.) in subtropical northeastern Himalayas

Science.gov (United States)

Marwein, M. A.; Choudhury, B. U.; Chakraborty, D.; Kumar, M.; Das, A.; Rajkhowa, D. J.

2017-05-01

Rainfed maize production in the hilly ecosystem of Northeastern Himalayas often suffers from moisture and soil acidity induced abiotic stresses. The present study measured evapotranspiration loss (ETc) of maize crop under controlled condition (pot experiment) of water deficit (W25-25 % and W50-50 % of field capacity soil moistures) and well watered (W100 = 100 % of field capacity (FC)) regimes in strong acid soils (pH = 4.3) of the Northeastern Himalayan Region of India. The response of soil ameliorants (lime) and phosphorus (P) nutrition under differential water regimes on ETc losses and water use efficiency was also studied. The measured seasonal ETc loss varied from 124.3 to 270.9 mm across treatment combinations. Imposition of water deficit stress resulted in significant ( p < 0.05) reduction (by 33-50 %) of seasonal ETc losses but was at the cost of delay in tasseling to silking, 47-65 % reduction in dry matter accumulation (DMA), 12-22 days shortening of grain formation period, and complete kernel abortion. Liming @ 4 t ha-1 significantly ( p < 0.05) increased ETc losses and DMA across water regimes but the magnitude of increase was higher in severely water deficit (W25) regime. Unlike lime, P nutrition improved DMA only in well-watered regimes (W100) while seasonal ETc loss was unaffected. Vegetative stage (tillering to tasseling) contributed the maximum ETc losses while weekly crop ETc loss was estimated highest during 11th-14th week after sowing (coincided with blistering stage) and then declined. Water use efficiency estimated from dry matter produced per unit ETc losses and irrigation water used varied from 4.33 to 9.43 g dry matter kg-1 water and 4.21 to 8.56 g dry matter kg-1, respectively. Among the input factors (water, P, and lime), water regime most strongly influenced the ETc loss, growth duration, grain formation, and water use efficiency of maize.

Response of water deficit regime and soil amelioration on evapotranspiration loss and water use efficiency of maize (Zea mays l.) in subtropical northeastern Himalayas.

Science.gov (United States)

Marwein, M A; Choudhury, B U; Chakraborty, D; Kumar, M; Das, A; Rajkhowa, D J

2017-05-01

Rainfed maize production in the hilly ecosystem of Northeastern Himalayas often suffers from moisture and soil acidity induced abiotic stresses. The present study measured evapotranspiration loss (ET c ) of maize crop under controlled condition (pot experiment) of water deficit (W 25 -25 % and W 50 -50 % of field capacity soil moistures) and well watered (W 100  = 100 % of field capacity (FC)) regimes in strong acid soils (pH = 4.3) of the Northeastern Himalayan Region of India. The response of soil ameliorants (lime) and phosphorus (P) nutrition under differential water regimes on ET c losses and water use efficiency was also studied. The measured seasonal ET c loss varied from 124.3 to 270.9 mm across treatment combinations. Imposition of water deficit stress resulted in significant (p losses but was at the cost of delay in tasseling to silking, 47-65 % reduction in dry matter accumulation (DMA), 12-22 days shortening of grain formation period, and complete kernel abortion. Liming @ 4 t ha -1 significantly (p losses and DMA across water regimes but the magnitude of increase was higher in severely water deficit (W 25 ) regime. Unlike lime, P nutrition improved DMA only in well-watered regimes (W 100 ) while seasonal ET c loss was unaffected. Vegetative stage (tillering to tasseling) contributed the maximum ET c losses while weekly crop ET c loss was estimated highest during 11th-14th week after sowing (coincided with blistering stage) and then declined. Water use efficiency estimated from dry matter produced per unit ET c losses and irrigation water used varied from 4.33 to 9.43 g dry matter kg -1  water and 4.21 to 8.56 g dry matter kg -1 , respectively. Among the input factors (water, P, and lime), water regime most strongly influenced the ET c loss, growth duration, grain formation, and water use efficiency of maize.

Water Use Efficiency of China's Terrestrial Ecosystems and Responses to Drought

Science.gov (United States)

Liu, Y.; Xiao, J.; Ju, W.; Zhou, Y.; Wang, S.; Wu, X.

2015-12-01

Yibo Liu1, 2, Jingfeng Xiao2, Weimin Ju3, Yanlian Zhou4, Shaoqiang Wang5, Xiaocui Wu31 Jiangsu Key Laboratory of Agricultural Meteorology, School of Applied Meteorology, Nanjing University of Information Science and Technology, Nanjing, 210044, China, 2Earth Systems Research Center, Institute for the Study of Earth, Oceans, and Space, University of New Hampshire, Durham, NH 03824, USA, 3 International Institute for Earth System Sciences, Nanjing University, Nanjing, 210023, China, 4 School of Geographic and Oceanographic Sciences, Nanjing University, Nanjing, 210023, China, 5 Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, 100101, China Water use efficiency (WUE) measures the trade-off between carbon gain and water loss of terrestrial ecosystems, and better understanding its dynamics and controlling factors is essential for predicting ecosystem responses to climate change. We assessed the magnitude, spatial patterns, and trends of WUE of China's terrestrial ecosystems and its responses to drought using a process-based ecosystem model. During the period from 2000 to 2011, the national average annual WUE (net primary productivity (NPP)/evapotranspiration (ET)) of China was 0.79 g C kg-1 H2O. Annual WUE decreased in the southern regions because of the decrease in NPP and increase in ET and increased in most northern regions mainly because of the increase in NPP. Droughts usually increased annual WUE in Northeast China and central Inner Mongolia but decreased annual WUE in central China. "Turning-points" were observed for southern China where moderate and extreme drought reduced annual WUE and severe drought slightly increased annual WUE. The cumulative lagged effect of drought on monthly WUE varied by region. Our findings have implications for ecosystem management and climate policy making. WUE is expected to continue to change under future climate

QTL analysis by sequencing of Water Use Efficiency (WUE) in potato

DEFF Research Database (Denmark)

Kaminski, Kacper Piotr; Sønderkær, Mads; Sørensen, Kirsten Kørup

2013-01-01

The traditional approach to potato breeding, the classical “mate and phenotype” approach is relatively costly and because phenotyping and growth capacity is limited, this are being slowly replaced by Marker Assisted Selection (MAS) breeding schemes. MAS is based on the presence of DNA polymorphic.......sparsipilum), phenotyped for water use efficiency. This population has also previously been phenotyped for the total glycoalkaloid (TGA) content....... and time consuming process. Here, a novel method for Quantitative Trait Locus (QTL) analysis has been developed, that allows for development of specific markers by use of genomic sequence reads and the recently published reference genome sequence for potato. Prior to sequencing the mapping population...

Transpiration and water use efficiency in native chilean and exotic species, a usefull tool for catchment management?

Science.gov (United States)

Hervé-Fernández, P.; Oyarzun, C. E.

2012-04-01

Land-use and forest cover change play important roles in socio-economic processes and have been linked with water supply and other ecosystem services in various regions of the world. Water yield from watersheds is a major ecosystem service for human activities but has been altered by landscape management superimposed on climatic variability and change. Sustaining ecosystem services important to humans, while providing a dependable water supply for agriculture and urban needs is a major challenge faced by managers of human-dominated or increased antropical effect over watersheds. Since water is mostly consumed by vegetation (i.e: transpiration), which strongly depends on trees physiological characteristics (i.e: foliar area, transpiration capacity) are very important. The quantity of water consumed by plantations is influenced mainly by forest characteristics (species physiology, age and management), catchment water retention capacity and meteorological characteristics. Eventhough in Chile, the forest sector accounts for 3.6% of the gross domestic product (GDP) and 12.5% of total exports (INFOR, 2003), afforestation with fast growing exotic species has ended up being socially and politically questionable because of the supposed impact on the environment and water resources. We present data of trees transpiration and water use efficiency from three headwater catchments: (a) second growth native evergreen forest (Aetoxicon punctatum, Drimys winterii, Gevuina avellana, Laureliopsis philippiana); (b) Eucalyptus globulus plantation, and (c) a mixed native deciduous (Nothofagus obliqua and some evergreen species) forest and Eucalyptus globulus and Acacia melanoxylon plantation located at the Coastal Mountain Range in southern Chile (40°S). Annual transpiration rates ranged from 1.24 ± 0.41 mol•m-2•s-1 (0.022 ± 0.009 L•m-2•s-1) for E. globulus, while the lowest observed was for L. philippiana 0.44 ± 0.31 mol•m-2•s-1 (0.008 ± 0.006 L•m-2•s-1). However

Linking plant functional trait plasticity and the large increase in forest water use efficiency

Science.gov (United States)

Mastrotheodoros, Theodoros; Pappas, Christoforos; Molnar, Peter; Burlando, Paolo; Keenan, Trevor F.; Gentine, Pierre; Gough, Christopher M.; Fatichi, Simone

2017-09-01

Elevated atmospheric CO2 concentrations are expected to enhance photosynthesis and reduce stomatal conductance, thus increasing plant water use efficiency. A recent study based on eddy covariance flux observations from Northern Hemisphere forests showed a large increase in inherent water use efficiency (IWUE). Here we used an updated version of the same data set and robust uncertainty quantification to revisit these contemporary IWUE trends. We tested the hypothesis that the observed IWUE increase could be attributed to interannual trends in plant functional traits, potentially triggered by environmental change. We found that IWUE increased by 1.3% yr-1, which is less than previously reported but still larger than theoretical expectations. Numerical simulations with the Tethys-Chloris ecosystem model using temporally static plant functional traits cannot explain this increase. Simulations with plant functional trait plasticity, i.e., temporal changes in model parameters such as specific leaf area and maximum Rubisco capacity, match the observed trends in IWUE. Our results show that trends in plant functional traits, equal to 1.0% yr-1, can explain the observed IWUE trends. Thus, at decadal or longer time scales, trait plasticity could potentially influence forest water, carbon, and energy fluxes with profound implications for both the monitoring of temporal changes in plant functional traits and their representation in Earth system models.

Virtual Water and Water Footprints: Overreaching Into the Discourse on Sustainability, Efficiency, and Equity

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Dennis Wichelns

2015-10-01

Full Text Available The notions of virtual water and water footprints were introduced originally to bring attention to the large amounts of water required to produce crops and livestock. Recently, several authors have begun applying those notions in efforts to describe efficiency, equity, and the sustainability of resources and production activities. In this paper, I describe why the notions of virtual water and water footprints are not appropriate for analysing issues pertaining to those topics. Both notions lack a supporting conceptual framework and they contain too little information to enhance understanding of important policy issues. Neither notion accounts for the opportunity cost or scarcity value of water in any setting, or the impacts of water availability and use on livelihoods. In addition, countries trade in goods and services – not in crop and livestock water requirements. Thus, the notions of virtual water and water footprints cannot provide helpful insight regarding the sustainability of water use, economic efficiency, or social equity. Gaining such insight requires the application of legitimate conceptual frameworks, representing a broad range of perspectives from the physical and social sciences, with due consideration of dynamics, uncertainty, and the impacts of policy choices on livelihoods and natural resources.

Catchment-scale groundwater recharge and vegetation water use efficiency

Science.gov (United States)

Troch, P. A. A.; Dwivedi, R.; Liu, T.; Meira, A.; Roy, T.; Valdés-Pineda, R.; Durcik, M.; Arciniega, S.; Brena-Naranjo, J. A.

2017-12-01

Precipitation undergoes a two-step partitioning when it falls on the land surface. At the land surface and in the shallow subsurface, rainfall or snowmelt can either runoff as infiltration/saturation excess or quick subsurface flow. The rest will be stored temporarily in the root zone. From the root zone, water can leave the catchment as evapotranspiration or percolate further and recharge deep storage (e.g. fractured bedrock aquifer). Quantifying the average amount of water that recharges deep storage and sustains low flows is extremely challenging, as we lack reliable methods to quantify this flux at the catchment scale. It was recently shown, however, that for semi-arid catchments in Mexico, an index of vegetation water use efficiency, i.e. the Horton index (HI), could predict deep storage dynamics. Here we test this finding using 247 MOPEX catchments across the conterminous US, including energy-limited catchments. Our results show that the observed HI is indeed a reliable predictor of deep storage dynamics in space and time. We further investigate whether the HI can also predict average recharge rates across the conterminous US. We find that the HI can reliably predict the average recharge rate, estimated from the 50th percentile flow of the flow duration curve. Our results compare favorably with estimates of average recharge rates from the US Geological Survey. Previous research has shown that HI can be reliably estimated based on aridity index, mean slope and mean elevation of a catchment (Voepel et al., 2011). We recalibrated Voepel's model and used it to predict the HI for our 247 catchments. We then used these predicted values of the HI to estimate average recharge rates for our catchments, and compared them with those estimated from observed HI. We find that the accuracies of our predictions based on observed and predicted HI are similar. This provides an estimation method of catchment-scale average recharge rates based on easily derived catchment

Participatory Irrigation Management and Irrigation Water Use Efficiency in Maize Production: Evidence from Zhangye City, Northwestern China

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Qing Zhou

2017-10-01

Full Text Available Water has become increasingly scarce in northwestern China due to climate change, economic growth and burgeoning population. Improving agriculture water use efficiency is of strategic significance in promoting socio-economic water productivity for arid and semi-arid inland river basins. Based on the household-level data collected in Zhangye City, which is located in the middle reaches of Heihe River Basin (HRB in northwestern China, irrigation water use efficiency (IWUE of maize is estimated based on stochastic frontier analysis. The impacts of influential factors, especially the participatory irrigation management (PIM through water user associations (WUAs, on IWUE were further examined. Results show that the estimated average Technical efficiency (TE and IWUE of maize production are 0.74 and 0.24, respectively. The participation level in irrigation management is very low, with only 40% of the respondents participating in WUA meetings. In addition, most have a relatively superficial understanding of the roles and management scheme of WUAs. Empirical results show that though significantly positive, the magnitude of the impact of PIM on IWUE is relatively small. Households that participated in WUA meetings achieved only 0.002% higher IWUEs than those have never participated in. WUAs are not operating with their designed objectives. Consequently, reform of the traditional management form of WUAs to make them more transparent, fair, and extensively participated in among farmers is in urgently need. In addition, we also find that water price, source of irrigation water, irrigation technology adoption and famers’ education level and farming experience also have significant positive impacts on IWUE.

Driven Factors Analysis of China’s Irrigation Water Use Efficiency by Stepwise Regression and Principal Component Analysis

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Renfu Jia

2016-01-01

Full Text Available This paper introduces an integrated approach to find out the major factors influencing efficiency of irrigation water use in China. It combines multiple stepwise regression (MSR and principal component analysis (PCA to obtain more realistic results. In real world case studies, classical linear regression model often involves too many explanatory variables and the linear correlation issue among variables cannot be eliminated. Linearly correlated variables will cause the invalidity of the factor analysis results. To overcome this issue and reduce the number of the variables, PCA technique has been used combining with MSR. As such, the irrigation water use status in China was analyzed to find out the five major factors that have significant impacts on irrigation water use efficiency. To illustrate the performance of the proposed approach, the calculation based on real data was conducted and the results were shown in this paper.

Long-term nitrogen additions and the intrinsic water-use efficiency of boreal Scots pine.

Science.gov (United States)

Marshall, John; Wallin, Göran; Linder, Sune; Lundmark, Tomas; Näsholm, Torgny

2015-04-01

Nitrogen fertilization nearly always increases productivity in boreal forests, at least in terms of wood production, but it is unclear how. In a mature (80 yrs. old) Scots pine forest in northern Sweden, we tested the extent to which nitrogen fertilization increased intrinsic photosynthetic water-use efficiency. We measured δ13C both discretely, in biweekly phloem sampling, and continuously, by monitoring of bole respiration. The original experiment was designed as a test of eddy covariance methods and is not therefore strictly replicated. Nonetheless, we compared phloem contents among fifteen trees from each plot and stem respiration from four per plot. The treatments included addition of 100 kg N/ha for eight years and a control. Phloem contents have the advantage of integrating over the whole canopy and undergoing complete and rapid turnover. Their disadvantage is that some have observed isotopic drift with transport down the length of the stem, presumably as a result of preferential export and/or reloading. We also measured the isotopic composition of stem respiration from four trees on each plot using a Picarro G1101-I CRDS attached to the vent flow from a continuous gas-exchange system. We detected consistent differences in δ13C between the treatments in phloem contents. Within each treatment, the phloem δ13C was negatively correlated with antecedent temperature (R2= 0.65) and no other measured climate variable. The isotopic composition of stem CO2 efflux will be compared to that of phloem contents. However, when converted to intrinsic water-use efficiency, the increase amounted to only about 4%. This is a small relative to the near doubling in wood production. Although we were able to detect a clear and consistent increase in water-use efficiency with N-fertilization, it constitutes but a minor cause of the observed increase in wood production.

Effects inoculation of mycorhizae species and irrigation levels impacts on growth criteria, yield and water use efficiency of corb (Zea mays L.

Directory of Open Access Journals (Sweden)

M.R. Amerian

2016-05-01

Full Text Available Water deficiency is one of the most important factors for limiting crop yield in arid and semiarid regions. Symbiosis with a variety of microorganisms in these regions is one of the modern ecological approaches for sustainable agriculture to reduce damages caused by environmental stresses. Symbiotic of arbuscular mycorrhizal fungi (AM with the roots of crops has shown positive effects on agricultural systems. In order to study the effects of inoculation with two species of mycorrhizal fungi and irrigation levels on root growth criteria and water use efficiency of corn, an experiment was performed as split plots based on a complete randomized block design with three replications at the Agricultural Research Station, Ferdowsi University of Mashhad during growing season of 2008-2009. Treatments included two mycorhizae inoculation (Glomus mosseae and G. intraradices and control and four irrigation levels (25, 50, 75 and 100% of water requirement. Grain yield, root specific length, the percentage of root colonization and water use efficiency based on grain yield of corn were measured. The results showed that the effect of mycorrhizae inoculation was significant on (p≤0.05 root specific length, grain yield and water use efficiency of corn. Mycorrhizae species had no significant effect on root colonization percentage of corn. Different irrigation levels had significant effect on grain yield, special length root, the percentage of root colonization, and water use efficiency of corn (p≤0.05. Generally, the results showed that mycorrhizae inoculation in water deficiency conditions, can increase the uptake of water and nutrients by developing the root and increasing the absorbing surface. In this way, not only the plant tolerance against the water deficiency increases, but also more yield will be produced for a specific value of water, which means the water use efficiency increases. Furthermore, the use of water will be decreased.

Highly Efficient Photocatalytic Water Splitting over Edge-Modified Phosphorene Nanoribbons.

Science.gov (United States)

Hu, Wei; Lin, Lin; Zhang, Ruiqi; Yang, Chao; Yang, Jinlong

2017-11-01

Two-dimensional phosphorene with desirable optoelectronic properties (ideal band gap, high carrier mobility, and strong visible light absorption) is a promising metal-free photocatalyst for water splitting. However, the band edge positions of the valence band maximum (VBM) and conduction band maximum (CBM) of phosphorene are higher than the redox potentials in photocatalytic water splitting reactions. Thus, phosphorene can only be used as the photocathode for hydrogen evolution reaction as a low-efficiency visible-light-driven photocatalyst for hydrogen production in solar water splitting cells. Here, we propose a new mechanism to improve the photocatalytic efficiency of phosphorene nanoribbons (PNRs) by modifying their edges for full reactions in photocatalytic water splitting. By employing first-principles density functional theory calculations, we find that pseudohalogen (CN and OCN) passivated PNRs not only show desired VBM and CBM band edge positions induced by edge electric dipole layer, but also possess intrinsic optoelectronic properties of phosphorene, for both water oxidation and hydrogen reduction in photocatalytic water splitting without using extra energy. Furthermore, our calculations also predict that the maximum energy conversion efficiency of heterojunction solar cells consisting of different edge-modified PNRs can be as high as 20% for photocatalytic water splitting.

Response of water use efficiency to summer drought in a boreal Scots pine forest in Finland

Science.gov (United States)

Gao, Yao; Markkanen, Tiina; Aurela, Mika; Mammarella, Ivan; Thum, Tea; Tsuruta, Aki; Yang, Huiyi; Aalto, Tuula

2017-09-01

The influence of drought on plant functioning has received considerable attention in recent years, however our understanding of the response of carbon and water coupling to drought in terrestrial ecosystems still needs to be improved. A severe soil moisture drought occurred in southern Finland in the late summer of 2006. In this study, we investigated the response of water use efficiency to summer drought in a boreal Scots pine forest (Pinus sylvestris) on the daily time scale mainly using eddy covariance flux data from the Hyytiälä (southern Finland) flux site. In addition, simulation results from the JSBACH land surface model were evaluated against the observed results. Based on observed data, the ecosystem level water use efficiency (EWUE; the ratio of gross primary production, GPP, to evapotranspiration, ET) showed a decrease during the severe soil moisture drought, while the inherent water use efficiency (IWUE; a quantity defined as EWUE multiplied with mean daytime vapour pressure deficit, VPD) increased and the underlying water use efficiency (uWUE, a metric based on IWUE and a simple stomatal model, is the ratio of GPP multiplied with a square root of VPD to ET) was unchanged during the drought. The decrease in EWUE was due to the stronger decline in GPP than in ET. The increase in IWUE was because of the decreased stomatal conductance under increased VPD. The unchanged uWUE indicates that the trade-off between carbon assimilation and transpiration of the boreal Scots pine forest was not disturbed by this drought event at the site. The JSBACH simulation showed declines of both GPP and ET under the severe soil moisture drought, but to a smaller extent compared to the observed GPP and ET. Simulated GPP and ET led to a smaller decrease in EWUE but a larger increase in IWUE because of the severe soil moisture drought in comparison to observations. As in the observations, the simulated uWUE showed no changes in the drought event. The model deficiencies exist

Yield Traits and Water and Nitrogen Use Efficiencies of Bell Pepper Grown in Plastic-Greenhouse

Directory of Open Access Journals (Sweden)

Vincenzo Candido

2009-09-01

Full Text Available We report the results of a two-year study assessing the effects of nitrogen fertilization and irrigation regimes on yield traits and on water and nitrogen use efficiency of greenhouse-grown bell pepper (Capsicum annuum L.. The trials involved the combination of four N doses (0, 100, 200, 300 kg ha-1 with two irrigation regimes (100% restitution of ETc; repeated cycles of water stress starting from fruit set. In the second year, the crop was transplanted one month earlier than in the first year and was mulched with plastic sheeting. The highest yield in both years was obtained by associating 100% restitution of ETc and the N dose of 200 kg ha-1. The marketable yields were 37 and 72 t ha-1 in 1998 and 1999, respectively. Doubling of the yield in the second year was probably due to the earlier transplantation and mulching, confirming the numerous benefits of the latter technique. The water deficit imposed during the late flowering-early fruit set phase had negative effects on the crop, with declines of the marketable yield of up to 44% due to the reduced number and weight of the fruit and the increased waste, mainly peppers with blossom-end rot, cracking, sun-burn and malformations. The peppers grown under water stress were richer in dry matter and soluble solids. The yield declines due to water deficit varied in relation to the N dose, as confirmed by the numerous interactions recorded between irrigation regime and nitrogen level.Without nitrogen fertilization, the quantity and quality of the fruits remained unchanged, while the maximum dose (300 kg ha-1 enhanced the negative effects of the water deficit on the number (-52% and weight (-161% of marketable peppers. Moreover, the waste peppers reached 31% of the total production (by weight, with over 21% affected by blossom-end rot. Water stress led to a drastic reduction of the total above-ground dry biomass (40% and a significant decrease of nitrogen absorption by the plant (54% with preferential

Moss and peat hydraulic properties are optimized to maximise peatland water use efficiency

Science.gov (United States)

Kettridge, Nicholas; Tilak, Amey; Devito, Kevin; Petrone, Rich; Mendoza, Carl; Waddington, Mike

2016-04-01

Peatland ecosystems are globally important carbon and terrestrial surface water stores that have formed over millennia. These ecosystems have likely optimised their ecohydrological function over the long-term development of their soil hydraulic properties. Through a theoretical ecosystem approach, applying hydrological modelling integrated with known ecological thresholds and concepts, the optimisation of peat hydraulic properties is examined to determine which of the following conditions peatland ecosystems target during this development: i) maximise carbon accumulation, ii) maximise water storage, or iii) balance carbon profit across hydrological disturbances. Saturated hydraulic conductivity (Ks) and empirical van Genuchten water retention parameter α are shown to provide a first order control on simulated water tensions. Across parameter space, peat profiles with hypothetical combinations of Ks and α show a strong binary tendency towards targeting either water or carbon storage. Actual hydraulic properties from five northern peatlands fall at the interface between these goals, balancing the competing demands of carbon accumulation and water storage. We argue that peat hydraulic properties are thus optimized to maximise water use efficiency and that this optimisation occurs over a centennial to millennial timescale as the peatland develops. This provides a new conceptual framework to characterise peat hydraulic properties across climate zones and between a range of different disturbances, and which can be used to provide benchmarks for peatland design and reclamation.

Increasing Water Use Efficiency Comes at a Cost for Norway Spruce

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Tanja G M Sanders

2016-11-01

Full Text Available Intrinsic water use efficiency (WUEi in trees is an indication of the ratio of carbon assimilation to the rate of transpiration. It is generally assumed that it is a response to water availability. In agricultural research, the question of drought tolerance by increased WUEi has been well studied. In general, the increase is a trade-off for productivity and is therefore not desired. For forest trees, this question is less clearly understood. Using stable carbon isotopes derived from tree rings combined with productivity as the product of the annual growth increment and annual density measurements, we compared the change in WUEi over a 15 year period. While WUEi increased over this period, the productivity decreased, causing an opposing trend. The gradient of the correlation between WUEi and productivity varies between provenances and sites. Counterintuitively, the populations at the drier site showed low WUEi values at the beginning of the investigation. Slopes vary with the provenance from Poland showing the least decline in productivity. In general, we found that a decline in productivity aligned with an increase in WUEi.

Survey the Effects of Partial Root Zone Deficit Irrigation and Deficit Irrigation on Quantitative, Qualitative and Water Use Efficiency of Pomegranate

OpenAIRE

mohammad saeed tadaion; Gholamreza Moafpourian

2017-01-01

Introduction: One of the latest efficient methods on increment of water use efficiency that confirmed by many scientists all over the world is deficit and alternative partial root zone deficit irrigation. In this experiment the effect of deficit and alternative partial root zone deficit irrigation on fruit yield, quality and water use efficiency of pomegranate (Punicagranatum (L.) cv. Zarde-anar) were investigatedin Arsenjan semi-arid region. Materials and Methods: The experiment was carri...

Canopy management and water use efficiency in vineyards under Mediterranean semiarid conditions

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de la Fuente Mario

2015-01-01

In addition, both positive effects of sprawl treatments (crop load and training system resulted in better yield and quality in Mediterranean semiarid conditions under the same inputs (sun, water and soil, causing higher efficiency of natural resources.

Efficiency improvement of a concentrated solar receiver for water heating system using porous medium

Science.gov (United States)

Prasartkaew, Boonrit

2018-01-01

This experimental study aims at investigating on the performance of a high temperature solar water heating system. To approach the high temperature, a porous-medium concentrated solar collector equipped with a focused solar heliostat were proposed. The proposed system comprised of two parts: a 0.7x0.7-m2 porous medium receiver, was installed on a 3-m tower, and a focused multi-flat-mirror solar heliostat with 25-m2 aperture area. The porous medium used in this study was the metal swarf or metal waste from lathing process. To know how the system efficiency could be improved by using such porous medium, the proposed system with- and without-porous medium were tested and the comparative study was performed. The experimental results show that, using porous medium for enhancing the heat transfer mechanism, the system thermal efficiency was increased about 25%. It can be concluded that the efficiency of the proposed system can be substantially improved by using the porous medium.

Stable carbon isotope composition (δ{sup 13}C), water use efficiency, and biomass productivity of Lycopersicon esculentum, Lycopersicon pennellii, and the F{sub 1} hybrid

Energy Technology Data Exchange (ETDEWEB)

Martin, B.; Thorstenson, Y. R.

1988-09-01

Three tomatoes, Lycopersicon esculentum Mill. cv UC82B, a droughttolerant wild related species, Lycopersicon pennellii (Cor.) D'Arcy, and their F{sub 1}, hybrid, were grown in containers maintained at three levels of soil moisture. Season-long water use was obtained by summing over the season daily weight losses of each container corrected for soil evaporation. Plant biomass was determined by harvesting and weighing entire dried plants. Season-long water use efficiency (gram dry weight/kilogram H{sub 2}O) was calculated by dividing the dry biomass by the season-long water use. The season-long water use efficiency was greatest in the wild parent, poorest in the domestic parent, and intermediate (but closer to the wild parent) in the F, hybrid. Instantaneous water-use efficiency (micromole CO{sub 2}/millimole H{sub 2}O) determined by gas exchange measurements on individual leaves was poorly correlated with season-long water use efficiency. However, the relative abundance of stable carbon isotopes of leaf tissue samples was strongly correlated with the season-long water use efficiency. Also, the isotopic composition and the season-long water use efficiency of each genotype alone were strongly negatively correlated with plant dry weight when the dry weight varied as a function of soil moisture. (author)

Efficiency evaluation of urban and rural municipal water service ...

African Journals Online (AJOL)

2016-01-01

Jan 1, 2016 ... systems have seen some success; however, the efficiency with which these water services ... literature, firms are now referred to as decision making units ..... is the most advisable method to use for water service providers as.

Sterols indicate water quality and wastewater treatment efficiency.

Science.gov (United States)

Reichwaldt, Elke S; Ho, Wei Y; Zhou, Wenxu; Ghadouani, Anas

2017-01-01

As the world's population continues to grow, water pollution is presenting one of the biggest challenges worldwide. More wastewater is being generated and the demand for clean water is increasing. To ensure the safety and health of humans and the environment, highly efficient wastewater treatment systems, and a reliable assessment of water quality and pollutants are required. The advance of holistic approaches to water quality management and the increasing use of ecological water treatment technologies, such as constructed wetlands and waste stabilisation ponds (WSPs), challenge the appropriateness of commonly used water quality indicators. Instead, additional indicators, which are direct measures of the processes involved in the stabilisation of human waste, have to be established to provide an in-depth understanding of system performance. In this study we identified the sterol composition of wastewater treated in WSPs and assessed the suitability of human sterol levels as a bioindicator of treatment efficiency of wastewater in WSPs. As treatment progressed in WSPs, the relative abundance of human faecal sterols, such as coprostanol, epicoprostanol, 24-ethylcoprostanol, and sitostanol decreased significantly and the sterol composition in wastewater changed significantly. Furthermore, sterol levels were found to be correlated with commonly used wastewater quality indicators, such as BOD, TSS and E. coli. Three of the seven sterol ratios that have previously been used to track sewage pollution in the environment, detected a faecal signal in the effluent of WSPs, however, the others were influenced by high prevalence of sterols originating from algal and fungal activities. This finding poses a concern for environmental assessment studies, because environmental pollution from waste stabilisation ponds can go unnoticed. In conclusion, faecal sterols and their ratios can be used as reliable indicators of treatment efficiency and water quality during wastewater

Carbon isotope discrimination as a selection tool for high water use efficiency and high crop yields

Energy Technology Data Exchange (ETDEWEB)

Kumarasinghe, K S; Kirda, C; Bowen, G D [Joint FAO/IAEA Div. of Nuclear Techniques in Food and Agriculture, Vienna (Austria). Soil Fertility, Irrigation and Crop Production Section; Zapata, F; Awonaike, K O; Holmgren, E; Arslan, A; De Bisbal, E C; Mohamed, A R.A.G.; Montenegro, A [FAO/IAEA Agriculture and Biotechnology Lab., Seibersdorf (Austria). Soils Science Unit

1996-07-01

Results of back-up research conducted at the FAO/IAEA Agriculture and Biotechnology Laboratory in support of the FAO/IAEA Co-ordinated Research Programme on the Use of Isotope Studies on Increasing and Stabilizing Plant Productivity in Low Phosphate and Semi-arid and Sub-humid Soils of the Tropics and Sub-tropics, are presented here. Neutron probe measurements confirmed the earlier reports of a strong correlation of {Delta} with grain yield and water use efficiency of wheat. High soil gypsum content and soil salinity, a wide spread problem in soils of arid and semi-arid climatic zones, do not interfere with the association of {Delta} with crop yields, provided plants are grown in similar soil water status and soil fertility level. Results of a glasshouse experiment using selected cowpea genotypes showed that {Delta} values measured at flowering stage positively correlated with total dry matter production and percent N{sub 2} derived from atmosphere (%Ndfa), contributing to an earlier report from the laboratory that it may be possible to use {Delta} values for screening of leguminous crops for high N{sub 2} fixation potential. {sup 13}C isotope discrimination in the leaves of Gliricidia sepium was measured to examine if the technique could be extended to studies with trees. Results of a glasshouse experiment with 18 provenances of Gliricidia sepium showed highly significant correlations of {Delta} with total dry matter production, water use efficiency and total N accumulated through biological nitrogen fixation. Although the correlation of {Delta} with water use efficiency and dry matter yield are relatively clear and better understood, the correlation with nitrogen fixation still needs a closer examination under different environmental conditions and with different species. (Abstract Truncated)

Green and technical efficient growth in Danish fresh water aquaculture

DEFF Research Database (Denmark)

Nielsen, Rasmus

2011-01-01

growth can be achieved by introducing new environmentally friendly water purification systems in Danish fresh water aquaculture. Data Envelopment Analysis is used to investigate whether different water purification systems and farm size influence technical efficiency. The empirical results indicate...

Schools water efficiency and awareness project

African Journals Online (AJOL)

driniev

2002-04-23

Apr 23, 2002 ... Schools Water Efficiency Project in February 2003, which supports several of the City's Water Demand ... of automatic flushing urinals (AFUs) alone in schools can save up .... to go back into the bag as the cistern is filling.

Role of aquaporins in determining transpiration and photosynthesis in water-stressed plants: crop water-use efficiency, growth and yield.

Science.gov (United States)

Moshelion, Menachem; Halperin, Ofer; Wallach, Rony; Oren, Ram; Way, Danielle A

2015-09-01

The global shortage of fresh water is one of our most severe agricultural problems, leading to dry and saline lands that reduce plant growth and crop yield. Here we review recent work highlighting the molecular mechanisms allowing some plant species and genotypes to maintain productivity under water stress conditions, and suggest molecular modifications to equip plants for greater production in water-limited environments. Aquaporins (AQPs) are thought to be the main transporters of water, small and uncharged solutes, and CO2 through plant cell membranes, thus linking leaf CO2 uptake from the intercellular airspaces to the chloroplast with water loss pathways. AQPs appear to play a role in regulating dynamic changes of root, stem and leaf hydraulic conductivity, especially in response to environmental changes, opening the door to using AQP expression to regulate plant water-use efficiency. We highlight the role of vascular AQPs in regulating leaf hydraulic conductivity and raise questions regarding their role (as well as tonoplast AQPs) in determining the plant isohydric threshold, growth rate, fruit yield production and harvest index. The tissue- or cell-specific expression of AQPs is discussed as a tool to increase yield relative to control plants under both normal and water-stressed conditions. © 2014 John Wiley & Sons Ltd.

Overexpression of AtABCG25 enhances the abscisic acid signal in guard cells and improves plant water use efficiency.

Science.gov (United States)

Kuromori, Takashi; Fujita, Miki; Urano, Kaoru; Tanabata, Takanari; Sugimoto, Eriko; Shinozaki, Kazuo

2016-10-01

In addition to improving drought tolerance, improvement of water use efficiency is a major challenge in plant physiology. Due to their trade-off relationships, it is generally considered that achieving stress tolerance is incompatible with maintaining stable growth. Abscisic acid (ABA) is a key phytohormone that regulates the balance between intrinsic growth and environmental responses. Previously, we identified AtABCG25 as a cell-membrane ABA transporter that export ABA from the inside to the outside of cells. AtABCG25-overexpressing plants showed a lower transpiration phenotype without any growth retardation. Here, we dissected this useful trait using precise phenotyping approaches. AtABCG25 overexpression stimulated a local ABA response in guard cells. Furthermore, AtABCG25 overexpression enhanced drought tolerance, probably resulting from maintenance of water contents over the common threshold for survival after drought stress treatment. Finally, we observed enhanced water use efficiency by overexpression of AtABCG25, in addition to drought tolerance. These results were consistent with the function of AtABCG25 as an ABA efflux transporter. This unique trait may be generally useful for improving the water use efficiency and drought tolerance of plants. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Simple Retrofit High-Efficiency Natural Gas Water Heater Field Test

Energy Technology Data Exchange (ETDEWEB)

Schoenbauer, Ben [NorthernSTAR, St. Paul, MN (United States)

2017-03-01

High-performance water heaters are typically more time consuming and costly to install in retrofit applications, making high performance water heaters difficult to justify economically. However, recent advancements in high performance water heaters have targeted the retrofit market, simplifying installations and reducing costs. Four high efficiency natural gas water heaters designed specifically for retrofit applications were installed in single-family homes along with detailed monitoring systems to characterize their savings potential, their installed efficiencies, and their ability to meet household demands. The water heaters tested for this project were designed to improve the cost-effectiveness and increase market penetration of high efficiency water heaters in the residential retrofit market. The retrofit high efficiency water heaters achieved their goal of reducing costs, maintaining savings potential and installed efficiency of other high efficiency water heaters, and meeting the necessary capacity in order to improve cost-effectiveness. However, the improvements were not sufficient to achieve simple paybacks of less than ten years for the incremental cost compared to a minimum efficiency heater. Significant changes would be necessary to reduce the simple payback to six years or less. Annual energy savings in the range of $200 would also reduce paybacks to less than six years. These energy savings would require either significantly higher fuel costs (greater than $1.50 per therm) or very high usage (around 120 gallons per day). For current incremental costs, the water heater efficiency would need to be similar to that of a heat pump water heater to deliver a six year payback.

Simple Retrofit High-Efficiency Natural Gas Water Heater Field Test

Energy Technology Data Exchange (ETDEWEB)

Schoenbauer, Ben [NorthernSTAR, St. Paul, MN (United States)

2017-03-28

High performance water heaters are typically more time consuming and costly to install in retrofit applications, making high performance water heaters difficult to justify economically. However, recent advancements in high performance water heaters have targeted the retrofit market, simplifying installations and reducing costs. Four high efficiency natural gas water heaters designed specifically for retrofit applications were installed in single-family homes along with detailed monitoring systems to characterize their savings potential, their installed efficiencies, and their ability to meet household demands. The water heaters tested for this project were designed to improve the cost-effectiveness and increase market penetration of high efficiency water heaters in the residential retrofit market. The retrofit high efficiency water heaters achieved their goal of reducing costs, maintaining savings potential and installed efficiency of other high efficiency water heaters, and meeting the necessary capacity in order to improve cost-effectiveness. However, the improvements were not sufficient to achieve simple paybacks of less than ten years for the incremental cost compared to a minimum efficiency heater. Significant changes would be necessary to reduce the simple payback to six years or less. Annual energy savings in the range of $200 would also reduce paybacks to less than six years. These energy savings would require either significantly higher fuel costs (greater than $1.50 per therm) or very high usage (around 120 gallons per day). For current incremental costs, the water heater efficiency would need to be similar to that of a heat pump water heater to deliver a six year payback.

Water Use Efficiency under Different Tillage and Irrigation Systems for Tomato Farming in Southeastern Brazil

Science.gov (United States)

Bhering, S. B.; Fernandes, N. F.; Macedo, J. R.

2009-04-01

In the northwest part of Rio de Janeiro state water availability is one of the main limiting factors for human development and crop productivity. In the same way that shortage of freshwater is one of the main problems, the tomato production systems waste water and highly degrade the environment. The search for the water use efficiency is a challenge in tomato sustainable development production systems. This study aimed to contribute towards the development of sustainable production systems for the tomato farming in the northwestern part or Rio de Janeiro state, as well as increase water use efficiency and the improvement of our understanding on the role played by soil and water management practices on soil hydrology, especially on the amount of water available for the plants. The study was carried out at an experimental watershed in the city of São José do Ubá, in the northwestern portion of Rio de Janeiro state. This city has one of the worst human development index (HDI = 0718) of the state, occupying one of the last 6 positions (85 in 91), with serious problems of education, sanitation, water supply and public health. This area is characterized by an extensive steep hilly topography constituted by long convex-concave hillslopes separated by flat valley-bottoms. The original Atlantic Forest was continuously removed for the introduction of farming and grazing activities, which currently dominate the landscape of the region. The combination of such topographic and land-use characteristics tend to generate a variety of erosional processes, including rill and interrill erosion, gullies and even landslides. The average annual rainfall in the area is about 1,171 mm, with most of rain concentrated during the summer season, making December the wetter and July the drier months. The water balance is negative for most of the year, with the exception of the period from November to January. The cultivation in the area is traditionally done using production systems that

Water and nitrogen use efficiency under limited water supply for maize to increase land productivity

International Nuclear Information System (INIS)

Craciun, I.; Craciun, M.

1995-01-01

As drought is the main environmental factor limiting productivity, the study of plant response to water deficit has been one of the major research topics. The increasing of maize evapotranspiration ET does not always mean the increase of efficiency because, the brightest ET value does not always mean the highest grain yield value, AS the result of the mechanisms relating to the grain yield and ET which are far from simple. The rain amount and distribution during the reproductive stage is the main meteorological factor in flouncing yield. In our study 1991, the high soil moisture content determines a reduction of maize grain yield, in the wet years due to excess of water under irrigation conditions which normally limits root development as a result of insufficient oxygen for transpiration and lac ha of nitrate formation, the yield response to water deficit of different hybrids is of major importance in production planing. The available water supply would be directed towards fully meeting requirements of the hybrids with the higher K sub y over the restricted area and for the hybrids with a lower K sub y, the overall production will increase by extending the area under irrigation, without fully meeting water requirement provided water deficit do not exceed critical values.1 tab; 9 figs (Author)

Dryland maize yields and water use efficiency in response to tillage/crop stubble and nutrient management practices in China

NARCIS (Netherlands)

Wang, X.B.; Dai, K.; Zhang, D.; Zhang, X.; Wang, Y.; Zhao, Q.; Cai, D.X.; Hoogmoed, W.B.; Oenema, O.

2011-01-01

Rainfed crop production in northern China is constrained by low and variable rainfall. This study explored the effects of tillage/crop residue and nutrient management practices on maize (Zea mays L.) yield, water use efficiency (WUE), and N agronomic use efficiency (NAE) at Shouyang Dryland Farming

Energy Efficiency, Water Efficiency, and Renewable Energy Site Assessment: Mendenhall Glacier Visitor Center, Juneau, Alaska

Energy Technology Data Exchange (ETDEWEB)

Salasovich, James [National Renewable Energy Lab. (NREL), Golden, CO (United States); LoVullo, David [National Renewable Energy Lab. (NREL), Golden, CO (United States); Kandt, Alicen [National Renewable Energy Lab. (NREL), Golden, CO (United States)

2016-01-21

This report summarizes results from the energy efficiency, water efficiency, and renewable energy site assessment of the Mendenhall Glacier Visitor Center and site in Juneau, Alaska. The assessment is an American Society of Heating, Refrigerating, and Air-Conditioning Engineers Level 2 audit and meets Energy Independence and Security Act requirements. A team led by the U.S. Department of Energy's National Renewable Energy Laboratory conducted the assessment with U.S. Forest Service personnel August 19-20, 2015, as part of ongoing efforts by USFS to reduce energy and water use.

Assessing the effect of marginal water use efficiency on water use of loblolly pine and sweetgum in ambient and elevated CO2 conditions

Science.gov (United States)

Kim, D.; Medvigy, D.; Xu, X.; Oren, R.; Ward, E. J.

2017-12-01

Stomata are the common pathways through which diffusion of CO2 and water vapor take place in a plant. Therefore, the responses of stomatal conductance to environmental conditions are important to quantify carbon assimilation and water use of plants. In stomatal optimality theory, plants may adjust the stomatal conductance to maximize carbon assimilation for a given water availability. The carbon cost for unit water loss, marginal water use efficiency (λ), depends on changes in atmospheric CO2 concentration and pre-dawn leaf water potential. The relationship can be described by λ with no water stress (λ0) and the sensitivity of λ to pre-dawn leaf water potential (β0), which may vary by plant functional type. Assessment of sensitivity of tree and canopy water use to those parameters and the estimation of the parameters for individual plant functional type or species are needed. We modeled tree water use of loblolly pine (Pinus taeda) and sweetgum (Liquidambar styraciflua) in ambient and elevated CO2 (+200 µmol mol-1) at the Duke Forest free-air CO2 enrichment (FACE) site with Ecosystem Demography model 2 (ED2), a demographic terrestrial biosphere model that scales up individual-level competition for light, water and nutrients to the ecosystem-level. Simulated sap flux density for different tree size classes and species was compared to observations. The sensitivity analysis with respect to the model's hydraulic parameters was performed. The initial results showed that the impacts of λ on tree water use were greater than other hydraulic traits in the model, such as vertical hydraulic conductivity and leaf and stem capacitance. With 10% increase in λ, modeled water flow from root to leaf decreased by 2.5 and 1.6% for P. taeda and by 7.9 and 5.1% for L. styraciflua in ambient and elevated CO2 conditions, respectively. Values of hydraulic traits (λ0 and β0) for P. taeda and L. styraciflua in ambient an elevated CO2 conditions were also suggested.

Soil salinity and matric potential interaction on water use, water use efficiency and yield response factor of bean and wheat.

Science.gov (United States)

Khataar, Mahnaz; Mohhamadi, Mohammad Hossien; Shabani, Farzin

2018-02-08

We studied the effects of soil matric potential and salinity on the water use (WU), water use efficiency (WUE) and yield response factor (Ky), for wheat (Triticum aestivum cv. Mahdavi) and bean (Phaseoulus vulgaris cv. COS16) in sandy loam and clay loam soils under greenhouse conditions. Results showed that aeration porosity is the predominant factor controlling WU, WUE, Ky and shoot biomass (Bs) at high soil water potentials. As matric potential was decreased, soil aeration improved, with Bs, WU and Ky reaching maximum value at -6 to -10 kPa, under all salinities. Wheat WUE remained almost unchanged by reduction of matric potential under low salinities (EC ≤ 8 dSm -1 ), but increased under higher salinities (EC ≥ 8 dSm -1 ), as did bean WUE at all salinities, as matric potential decreased to -33 kPa. Wheat WUE exceeds that of bean in both sandy loam and clay loam soils. WUE of both plants increased with higher shoot/root ratio and a high correlation coefficient exists between them. Results showed that salinity decreases all parameters, particularly at high potentials (h = -2 kPa), and amplifies the effects of waterlogging. Further, we observed a strong relationship between transpiration (T) and root respiration (Rr) for all experiments.

Variation of inulin content, inulin yield and water use efficiency for inulin yield in Jerusalem artichoke genotypes under different water regimes

Science.gov (United States)

The information on genotypic variation for inulin content, inulin yield and water use efficiency of inulin yield (WUEi) in response to drought is limited. This study was to investigate the genetic variability in inulin content, inulin yield and WUEi of Jerusalem artichoke (Helianthus tuberosus L.) ...

An International Survey of Electric Storage Tank Water Heater Efficiency and Standards

Energy Technology Data Exchange (ETDEWEB)

Johnson, Alissa; Lutz, James; McNeil, Michael A.; Covary, Theo

2013-11-13

Water heating is a main consumer of energy in households, especially in temperate and cold climates. In South Africa, where hot water is typically provided by electric resistance storage tank water heaters (geysers), water heating energy consumption exceeds cooking, refrigeration, and lighting to be the most consumptive single electric appliance in the home. A recent analysis for the Department of Trade and Industry (DTI) performed by the authors estimated that standing losses from electric geysers contributed over 1,000 kWh to the annual electricity bill for South African households that used them. In order to reduce this burden, the South African government is currently pursuing a programme of Energy Efficiency Standards and Labelling (EES&L) for electric appliances, including geysers. In addition, Eskom has a history of promoting heat pump water heaters (HPWH) through incentive programs, which can further reduce energy consumption. This paper provides a survey of international electric storage water heater test procedures and efficiency metrics which can serve as a reference for comparison with proposed geyser standards and ratings in South Africa. Additionally it provides a sample of efficiency technologies employed to improve the efficiency of electric storage water heaters, and outlines programs to promote adoption of improved efficiency. Finally, it surveys current programs used to promote HPWH and considers the potential for this technology to address peak demand more effectively than reduction of standby losses alone

Species-specific intrinsic water use efficiency and its mediation of carbon assimilation during the drought

Science.gov (United States)

Yi, K.; Wenzel, M. K.; Maxwell, J. T.; Novick, K. A.; Gray, A.; Roman, D. T.

2015-12-01

Drought is expected to occur more frequently and intensely in the future, and many studies have suggested frequent and intense droughts can significantly alter carbon and water cycling in forest ecosystems, consequently decreasing the ability of forests to assimilate carbon. Predicting the impact of drought on forest ecosystem processes requires an understanding of species-specific responses to drought, especially in eastern US where species composition is highly dynamic. An emerging approach for describing species-specific drought response is to classify the plant water use strategy into isohydric and anisohydric behaviors. Trees utilizing isohydric behavior regulate water potential by closing stomata to reduce water loss during drought conditions, while anisohydric trees allow water potential to drop by sustaining stomatal conductance, but with the risk of hydraulic failure caused by cavitation of xylem tissues. Since catastrophic cavitation occurs infrequently in the relatively wet eastern U.S., we hypothesize that 1) tree growth of isohydric trees will be more limited during the drought than the anisohydric trees due to decreased stomatal conductance, but 2) variation in intrinsic water use efficient (iWUE) during drought in isohydric trees will mediate the effects of drought on carbon assimilation. We will test these hypotheses by 1) analyzing tree-ring chronologies and dendrometer data on productivity, and 2) estimating intrinsic water use efficiency (iWUE) at multiple scales by analyzing gas exchange data for the leaf-level, inter-annual variability of d13C in tree stem cores for the tree-level, and eddy covariance technique for the stand-level. Our study site is the Morgan-Monroe State Forest (Indiana, USA). A 46 m flux tower has been continuously recording the carbon, water and energy fluxes, and tree diameter has been measured every 2 weeks using dendrometers, since 1998. Additional research, including gas exchange measurements performed during the

Cyclic use of saline and non-saline water to increase water use efficiency and soil sustainability on drip irrigated maize in a semi-arid region

International Nuclear Information System (INIS)

Hassanli, M.; Ebrahimian, H.

2016-01-01

Use of saline water for irrigation is a strategy to mitigate water shortage. The objective of this study was to investigate the impact of the cyclic and constant use of saline and non-saline water on drip irrigated maize yield and irrigation water use efficiency (IWUE). Nine field treatments were laid out based on alternative irrigation management of non-saline and saline water combinations. The treatments were: two salinity levels of 3.5 and 5.7 dS/m and freshwater (0.4 dS/m) application in every one, three and five saline water application (1:1, 3:1 and 5:1, respectively). Results showed that the 1:1 combination management was the best in terms of crop yield and IWUE. In this treatment, salt concentration at the end of growing season was not significantly changed compared to its initial condition. If off-season precipitation or leaching was available, the 3:1 and 5:1 treatments were appropriated. Highest and lowest values of IWUE were 15.3 and 8.7 kg/m3 for the 1:1 management using water salinity of 3.5 dS/m and the treatment of constant irrigation with water salinity of 5.7 dS/m, respectively. Under low off-season precipitations, artificial leaching is essential for land sustainability in most treatments.

Cyclic use of saline and non-saline water to increase water use efficiency and soil sustainability on drip irrigated maize in a semi-arid region

Energy Technology Data Exchange (ETDEWEB)

Hassanli, M.; Ebrahimian, H.

2016-07-01

Use of saline water for irrigation is a strategy to mitigate water shortage. The objective of this study was to investigate the impact of the cyclic and constant use of saline and non-saline water on drip irrigated maize yield and irrigation water use efficiency (IWUE). Nine field treatments were laid out based on alternative irrigation management of non-saline and saline water combinations. The treatments were: two salinity levels of 3.5 and 5.7 dS/m and freshwater (0.4 dS/m) application in every one, three and five saline water application (1:1, 3:1 and 5:1, respectively). Results showed that the 1:1 combination management was the best in terms of crop yield and IWUE. In this treatment, salt concentration at the end of growing season was not significantly changed compared to its initial condition. If off-season precipitation or leaching was available, the 3:1 and 5:1 treatments were appropriated. Highest and lowest values of IWUE were 15.3 and 8.7 kg/m3 for the 1:1 management using water salinity of 3.5 dS/m and the treatment of constant irrigation with water salinity of 5.7 dS/m, respectively. Under low off-season precipitations, artificial leaching is essential for land sustainability in most treatments.

Energy efficiency of elevated water supply tanks for high-rise buildings

International Nuclear Information System (INIS)

Cheung, C.T.; Mui, K.W.; Wong, L.T.

2013-01-01

Highlights: ► We evaluate energy efficiency for water supply tank location in buildings. ► Water supply tank arrangement in a building affects pumping energy use. ► We propose a mathematical model for optimal design solutions. ► We test the model with measurements in 22 Hong Kong buildings. ► A potential annual energy saving for Hong Kong is up to 410 TJ. -- Abstract: High-rise housing, a trend in densely populated cities around the world, increases the energy use for water supply and corresponding greenhouse gas emissions. This paper presents an energy efficiency evaluation measure for water supply system designs and a mathematical model for optimizing pumping energy through the arrangement of water tanks in a building. To demonstrate that the model is useful for establishing optimal design solutions that integrate energy consumption into urban water planning processes which cater to various building demands and usage patterns, measurement data of 22 high-rise residential buildings in Hong Kong are employed. The results show the energy efficiency of many existing high-rise water supply systems is about 0.25 and can be improved to 0.26–0.37 via water storage tank relocations. The corresponding annual electricity that can be saved is 160–410 TJ, a 0.1–0.3% of the total annual electricity consumption in Hong Kong.

Can deficit irrigation techniques be used to enhance phosphorus and water use efficiency and benefit crop yields?

Science.gov (United States)

Wright, Hannah R.; Dodd, Ian C.; Blackwell, Martin S. A.; Surridge, Ben W. J.

2015-04-01

Soil drying and rewetting (DRW) affects the forms and availability of phosphorus (P). Water soluble P has been reported to increase 1.8- to 19-fold after air-drying with the majority of the increase (56-100%) attributable to organic P. Similarly, in two contrasting soil types DRW increased concentrations of total P and reactive P in leachate, likely due to enhanced P mineralisation and physiochemical processes causing detachment of soil colloids, with faster rewetting rates related to higher concentrations of P. The intensity of drying as well as the rate of rewetting influences organic and inorganic P cycling. How these dynamics are driven by soil water status, and impact crop P acquisition and growth, remains unclear. Improving P and water use efficiencies and crop yields is globally important as both P and water resources become increasingly scarce, whilst demand for food increases. Irrigation supply below the water requirement for full crop evapotranspiration is employed by agricultural practitioners where water supply is limited. Regulated deficit irrigation describes the scheduling of water supply to correspond to the times of highest crop demand. Alternate wetting and drying (AWD) is applied in lowland irrigated rice production to avoid flooding at certain times of crop development, and has benefited P nutrition and yields. This research aims to optimise the benefits of P availability and uptake achieved by DRW by guiding deficit irrigation management strategies. Further determination of underlying processes driving P cycling at fluctuating soil moisture status is required. Presented here is a summary of the literature on DRW effects on soil P availability and plant P uptake and partitioning, in a range of soil types and cropping systems, with emphasis on alternate wetting and drying irrigation (AWD) compared to continuous flooding in lowland irrigated rice production. Soil water contents and matric potentials, and effects on P dynamics, are highly variable

Increased water-use efficiency does not lead to enhanced tree growth under xeric and mesic conditions

NARCIS (Netherlands)

Lévesque, M.; Siegwolf, R.; Saurer, M.; Eilmann, B.; Rigling, A.

2014-01-01

Higher atmospheric CO2 concentrations (ca ) can under certain conditions increase tree growth by enhancing photosynthesis, resulting in an increase of intrinsic water-use efficiency (i WUE) in trees. However, the magnitude of these effects and their interactions with changing climatic conditions are

Regenerating degraded soils and increasing water use efficiency on vegetable farms in Uruguay through ecological intensification

NARCIS (Netherlands)

Alliaume, F.

2016-01-01

This thesis investigated alternative soil management strategies for vegetable crop systems and their hypothesized effects on increasing systems resilience by sequestering soil carbon, increasing the efficiency of water use, and reducing erosion. The goal was to contribute knowledge on and tools

Enhanced energy efficiency and water efficiency by gray water recycling with prearranged heat recycling; Hohe Energie- und Wassereffizienz durch Grauwasserrecycling mit vorgeschalteter Waermerueckgewinnung

Energy Technology Data Exchange (ETDEWEB)

Nolde, Erwin

2012-12-15

Up to now, the purely centrally oriented supply and disposal of water is only low resource efficient. It is highlighted with pleasure, that thermal energy also is removed from waste water in order to heat and cool buildings and business. Till to now, neither a water supply nor a central waste water treatment system is known which produces more energy than primary energy is used. This becomes evenly possible by means of gray water recycling. Due to the relatively low costs of investment, the users and the environment benefit together from the gray water recycling.

Nitrogen use efficiency evaluation of aerobic rice under field capacity water potential using 15N isotopic tracer technique

International Nuclear Information System (INIS)

Wahid, Ahmad Nazrul Abd; Rahim, Sahibin Abd; Rahim, Khairuddin Abdul; Harun, Abdul Rahim

2015-01-01

This study was carried out to evaluate the efficiency use of the nitrogen fertilizer on aerobic rice varieties MR219-4 and MR219-9 which were grown aerobically under field capacity water potential at the controlled environment area or shield house. Direct 15 N isotope tracer method was used in this study, whereby the 15 N isotope was utilized as a tracer for nitrogen nutrient uptake. 15 N isotope presence in the samples is determined by using emission spectrometer analysis and percentage of total nitrogen is determined by using Kjeldahl method. 15 N atom access value contained in the sample will be used in determining the effectiveness of the use of nitrogen in fertilizers through the specific calculation formulas. In this work, the data several data of nitrogen derived from fertilizer (Ndff), total nitrogen, nitrogen uptake and nitrogen use efficiency was obtained

Batteries for efficient energy extraction from a water salinity difference.

Science.gov (United States)

La Mantia, Fabio; Pasta, Mauro; Deshazer, Heather D; Logan, Bruce E; Cui, Yi

2011-04-13

The salinity difference between seawater and river water is a renewable source of enormous entropic energy, but extracting it efficiently as a form of useful energy remains a challenge. Here we demonstrate a device called "mixing entropy battery", which can extract and store it as useful electrochemical energy. The battery, containing a Na(2-x)Mn(5)O(10) nanorod electrode, was shown to extract energy from real seawater and river water and can be applied to a variety of salt waters. We demonstrated energy extraction efficiencies of up to 74%. Considering the flow rate of river water into oceans as the limiting factor, the renewable energy production could potentially reach 2 TW, or ∼13% of the current world energy consumption. The mixing entropy battery is simple to fabricate and could contribute significantly to renewable energy in the future.

Grazing Effects on Water Use Efficiency on a Mongolian Desert Steppe

Science.gov (United States)

Shao, C.; Chen, J.; Li, L.; John, R.; Ouyang, Z.

2015-12-01

Ecosystem-level water use efficiency (WUE), defined as the ratio of gross primary production (GPP) to evapotranspiration (ET), was assessed by continuous and simultaneous direct eddy-covariance (EC) measurements of carbon and water fluxes on adjacent pastures of grazed (DS) and ungrazed steppes (FS) in the Mongolia Plateau for a two-year period from 2010 to 2012. We found that the WUE was well positively linear correlated (r2=0.90) with the GEP both in the DS and FS. Due to our desert steppe was very sensitive to the precipitation, WUE was co-varied with the precipitation. WUE increased with the GEP increase under good water conditions, when the GEP reached its maximal value (DS: 3 g C m-2, FS: 2 g C m-2), the WUE was suppressed and kept a stable value during the peak growing season. Both GEP and WUE was near zero when the soil moisture was lower. We also found that the WUE was negatively correlated with ET. The WUE was higher in GS than that in FS. The mean seasonal WUE was 0.93 in GS and 0.54 g C kg-1 H2O in FS, with a peak monthly WUE of 1.32 in GS and 0.73 g C kg-1 H2O in FS, respectively. The difference between GS and FS mainly caused by that the ET was changed with the GEP during the entire growing season. This suggests the importance of both plant population dynamics and water statues should be considered in WUE studies.

Efficient degradation of trichloroethylene in water using persulfate activated by reduced graphene oxide-iron nanocomposite.

Science.gov (United States)

Ahmad, Ayyaz; Gu, Xiaogang; Li, Li; Lv, Shuguang; Xu, Yisheng; Guo, Xuhong

2015-11-01

Graphene oxide (GO) and nano-sized zero-valent iron-reduced graphene oxide (nZVI-rGO) composite were prepared. The GO and nZVI-rGO composite were characterized by transmission electron microscopy (TEM), Fourier transform infrared (FTIR), energy-dispersive spectroscopy (EDS), and Raman spectroscopy. The size of nZVI was about 6 nm as observed by TEM. The system of nZVI-rGO and persulfate (PS) was used for the degradation of trichloroethylene (TCE) in water, and showed 26.5% more efficiency as compared to nZVI/PS system. The different parameters were studied to determine the efficiency of nZVI-rGO to activate the PS system for the TCE degradation. By increasing the PS amount, TCE removal was also improved while no obvious effect was observed by varying the catalyst loading. Degradation was decreased as the TCE initial concentration was increased from 20 to 100 mg/L. Moreover, when initial solution pH was increased, efficiency deteriorated to 80%. Bicarbonate showed more negative effect on TCE removal among the solution matrix. To better understand the effects of radical species in the system, the scavenger tests were performed. The •SO4(-) and •O2(-) were predominant species responsible for TCE removal. The nZVI-rGO-activated PS process shows potential applications in remediation of highly toxic organic contaminants such as TCE present in the groundwater. Graphical abstract Persulfate activated by reduced graphene oxide and nano-sized zero-valent iron composite can be used for efficient degradation of trichloroethylene (TCE) in water.

The response of winter wheat to water stress and nitrogen fertilizer use efficiency

International Nuclear Information System (INIS)

Wang, F.; Qi, M.; Wang, H.; Changjiu, Z.

1995-01-01

The response of winter wheat to water stress imposed at different crop growth stages by deficit irrigation and fertilizer use under several schemes of irrigation were evaluated on fine sandy soil and sand loam soil. The results showed that according to grain yield response factor K, the order of sensitive growth stages of winter wheat to water stress in decreasing sequence were booting to flowering ( K= 0.90), winter afterward to booting ( K= 0.69), flowering to milking ( K= 0.44) and milking to ripening ( K= 0.25). Field water efficiency would get 16.7 kg/mm.ha when no water stress in growth period, and when water stress has occurred in some growth stages, the value of it decreased by 5 - 20 percent. It was also found that high fertilizer application rate without split application would not significantly influence the yield on fine sandy soil. But schedule of irrigation affected the translocation of nitrogen in the plant. When water stress occurred in later growth stage, the ratio of NUE in gain to straw decreased, and fertilizer was available for crop only about one month after fertilizer application, excessive fertilizer rate would result in decrease of NUE by leaching of nitrogen in sandy soil. Total recovery of fertilizer at harvest was half amount of application. 6 refs; 10 tabs; ( author)

Green Fodder Production and Water Use Efficiency of Some Forage Crops under Hydroponic Conditions

OpenAIRE

Ghazi N. Al-Karaki; M. Al-Hashimi

2012-01-01

The objectives of this study were to evaluate five forage crops (alfalfa (Medicago sativa), barley (Hordeum vulgare), cowpea (Vigna unguiculata), sorghum (Sorghum bicolor), and wheat (Triticum aestivum)) for green fodder production and water use efficiency under hydroponic conditions. The experiment has been conducted under temperature-controlled conditions (24 ± 1°C) and natural window illumination at growth room of Soilless Culture Laboratory, Arabian Gulf University, Manama, Bahrain. The r...

The Energy Efficiency of Hot Water Production by Gas Water Heaters with a Combustion Chamber Sealed with Respect to the Room

Directory of Open Access Journals (Sweden)

Grzegorz Czerski

2014-08-01

Full Text Available This paper presents investigative results of the energy efficiency of hot water production for sanitary uses by means of gas-fired water heaters with the combustion chamber sealed with respect to the room in single-family houses and multi-story buildings. Additionally, calculations were made of the influence of pre-heating the air for combustion in the chimney and air supply system on the energy efficiency of hot water production. CFD (Computational Fluid Dynamics software was used for calculation of the heat exchange in this kind of system. The studies and calculations have shown that the use of gas water heaters with a combustion chamber sealed with respect to the room significantly increases the efficiency of hot water production when compared to traditional heaters. It has also been proven that the pre-heating of combustion air in concentric chimney and air supply ducts essentially improves the energy efficiency of gas appliances for hot water production.

Morphological plasticity of root growth under mild water stress increases water use efficiency without reducing yield in maize

Science.gov (United States)

Cai, Qian; Zhang, Yulong; Sun, Zhanxiang; Zheng, Jiaming; Bai, Wei; Zhang, Yue; Liu, Yang; Feng, Liangshan; Feng, Chen; Zhang, Zhe; Yang, Ning; Evers, Jochem B.; Zhang, Lizhen

2017-08-01

A large yield gap exists in rain-fed maize (Zea mays L.) production in semi-arid regions, mainly caused by frequent droughts halfway through the crop-growing period due to uneven distribution of rainfall. It is questionable whether irrigation systems are economically required in such a region since the total amount of rainfall does generally meet crop requirements. This study aimed to quantitatively determine the effects of water stress from jointing to grain filling on root and shoot growth and the consequences for maize grain yield, above- and below-ground dry matter, water uptake (WU) and water use efficiency (WUE). Pot experiments were conducted in 2014 and 2015 with a mobile rain shelter to achieve conditions of no, mild or severe water stress. Maize yield was not affected by mild water stress over 2 years, while severe stress reduced yield by 56 %. Both water stress levels decreased root biomass slightly but shoot biomass substantially. Mild water stress decreased root length but increased root diameter, resulting in no effect on root surface area. Due to the morphological plasticity in root growth and the increase in root / shoot ratio, WU under water stress was decreased, and overall WUE for both above-ground dry matter and grain yield increased. Our results demonstrate that an irrigation system might be not economically and ecologically necessary because the frequently occurring mild water stress did not reduce crop yield much. The study helps us to understand crop responses to water stress during a critical water-sensitive period (middle of the crop-growing season) and to mitigate drought risk in dry-land agriculture.

Morphological plasticity of root growth under mild water stress increases water use efficiency without reducing yield in maize

Directory of Open Access Journals (Sweden)

Q. Cai

2017-08-01

Full Text Available A large yield gap exists in rain-fed maize (Zea mays L. production in semi-arid regions, mainly caused by frequent droughts halfway through the crop-growing period due to uneven distribution of rainfall. It is questionable whether irrigation systems are economically required in such a region since the total amount of rainfall does generally meet crop requirements. This study aimed to quantitatively determine the effects of water stress from jointing to grain filling on root and shoot growth and the consequences for maize grain yield, above- and below-ground dry matter, water uptake (WU and water use efficiency (WUE. Pot experiments were conducted in 2014 and 2015 with a mobile rain shelter to achieve conditions of no, mild or severe water stress. Maize yield was not affected by mild water stress over 2 years, while severe stress reduced yield by 56 %. Both water stress levels decreased root biomass slightly but shoot biomass substantially. Mild water stress decreased root length but increased root diameter, resulting in no effect on root surface area. Due to the morphological plasticity in root growth and the increase in root ∕ shoot ratio, WU under water stress was decreased, and overall WUE for both above-ground dry matter and grain yield increased. Our results demonstrate that an irrigation system might be not economically and ecologically necessary because the frequently occurring mild water stress did not reduce crop yield much. The study helps us to understand crop responses to water stress during a critical water-sensitive period (middle of the crop-growing season and to mitigate drought risk in dry-land agriculture.

Efficient use of energy

CERN Document Server

Dryden, IGC

2013-01-01

The Efficient Use of Energy, Second Edition is a compendium of papers discussing the efficiency with which energy is used in industry. The collection covers relevant topics in energy handling and describes the more important features of plant and equipment. The book is organized into six parts. Part I presents the various methods of heat production. The second part discusses the use of heat in industry and includes topics in furnace design, industrial heating, boiler plants, and water treatment. Part III deals with the production of mechanical and electrical energy. It tackles the principles o

Survey the Effects of Partial Root Zone Deficit Irrigation and Deficit Irrigation on Quantitative, Qualitative and Water Use Efficiency of Pomegranate

Directory of Open Access Journals (Sweden)

mohammad saeed tadaion

2017-12-01

Full Text Available Introduction: One of the latest efficient methods on increment of water use efficiency that confirmed by many scientists all over the world is deficit and alternative partial root zone deficit irrigation. In this experiment the effect of deficit and alternative partial root zone deficit irrigation on fruit yield, quality and water use efficiency of pomegranate (Punicagranatum (L. cv. Zarde-anar were investigatedin Arsenjan semi-arid region. Materials and Methods: The experiment was carried out in a constant plots and randomized complete block design (RCBD with four replicationsin five years.Treatmentswere 1- full flood irrigation (100 percent crop water requirement (T1 2- flood irrigation with 100 percent crop water requirement as alternate partial root-zone irrigation(every irrigation conducted on one side of tree (T2 3- flood irrigation with 50 percent crop water requirement as regular deficit irrigation (T3 4- full two-side drip irrigation(with regard to crop water requirement (eight drippers with twolit/hour flow by two different individual networks (T4 5- alternate partial root-zone drip irrigation with 100 percent crop water requirement (T5 6- regular deficit drip irrigation with 50 percent crop water requirement (T6 in every irrigation period. Each experimental treatment includes four trees and 96 similar twelve years old trees overall. Cultivation practice was conducted similarly on all of the trees. Results and Discussion: Results showed that the highest yield and water use efficiency based on statistical analysis belong to both PRD treatments i.e. alternate partial root-zone drip irrigation with 100 percent crop water requirement and alternate partial root-zone flood irrigation with 100 percent crop water requirement, respectively, that both of them decreased water requirement for irrigation up to 35 and 50 percent in comparison tocontrol. Application of partial root drying irrigation on both traditional flood irrigation and drip

Effect of different levels of water consumptive use of squash under drip irrigation system on salt distribution, yield and water use efficiency

International Nuclear Information System (INIS)

Abd El-Moniem, M.; El-Gendy, R.W.; Gadalla, A.M.; Hamdy, A.; Zeedan, A.

2006-01-01

This study aims to trace the distribution of salts and fertilizers through drip irrigation system and the response of squash (yield and water use efficiency) to irrigation treatments, i.e. T1 (100 % ETc), T2 (75 % ETc) and T3 (50 % ETc). This study was carried out in Inshas sandy soil at the farm of Soil and Water Research Department, Nuclear Research Centre, Atomic Energy Authority, Egypt. Soil samples were taken from three sites (0, 12.5 and 25 cm distance from the emitters between drippers and laterals lines) for evaluating the salt content (horizontal and vertical directions within the soil depths). The obtained data pointed out that salt accumulation was noticed at the surface layer and was affected by the direction of soil water movement (horizontal and vertical motion). The highest salt concentrations were in 75 % and 50 % ETc treatments between emitters and laterals. As for the three sites, salt concentration behaved in the sequence: 25 >12.5 > 0 cm sites. For squash yield, the first treatment produced high yield without significant differences between the second treatment so, 75 % ETc treatment was considered the best one for saving water

Response of water use efficiency to summer drought in a boreal Scots pine forest in Finland

Directory of Open Access Journals (Sweden)

Y. Gao

2017-09-01

Full Text Available The influence of drought on plant functioning has received considerable attention in recent years, however our understanding of the response of carbon and water coupling to drought in terrestrial ecosystems still needs to be improved. A severe soil moisture drought occurred in southern Finland in the late summer of 2006. In this study, we investigated the response of water use efficiency to summer drought in a boreal Scots pine forest (Pinus sylvestris on the daily time scale mainly using eddy covariance flux data from the Hyytiälä (southern Finland flux site. In addition, simulation results from the JSBACH land surface model were evaluated against the observed results. Based on observed data, the ecosystem level water use efficiency (EWUE; the ratio of gross primary production, GPP, to evapotranspiration, ET showed a decrease during the severe soil moisture drought, while the inherent water use efficiency (IWUE; a quantity defined as EWUE multiplied with mean daytime vapour pressure deficit, VPD increased and the underlying water use efficiency (uWUE, a metric based on IWUE and a simple stomatal model, is the ratio of GPP multiplied with a square root of VPD to ET was unchanged during the drought. The decrease in EWUE was due to the stronger decline in GPP than in ET. The increase in IWUE was because of the decreased stomatal conductance under increased VPD. The unchanged uWUE indicates that the trade-off between carbon assimilation and transpiration of the boreal Scots pine forest was not disturbed by this drought event at the site. The JSBACH simulation showed declines of both GPP and ET under the severe soil moisture drought, but to a smaller extent compared to the observed GPP and ET. Simulated GPP and ET led to a smaller decrease in EWUE but a larger increase in IWUE because of the severe soil moisture drought in comparison to observations. As in the observations, the simulated uWUE showed no changes in the drought event. The

A Meta-analysis of Plant Photosynthetic Traits and Water-use efficiency Responses to Drought

Science.gov (United States)

Zhang, J.

2017-12-01

Drought is predicted to become more intense and frequent in many regions of the world in the context of climate change, especially in the semi-arid regions of the Northern Hemisphere. Understanding the plant photosynthetic traits (Pn, Gs and Tr) and water use efficiency (WUE) response to drought is very important with regard to plant growth and productivity, which could reflect the terrestrial primary productivity worldwide. We used a meta-analysis based on studies of a worldwide range and full plant species Pn, Gs, Tr and WUE under drought condition and aimed to determine the responses of Pn, Gs, Tr and WUE of different drought intensities (mild, moderate and severe), different photosynthetic pathways (C3 and C4) and growth forms (herbs, shrubs, trees and lianas). Furthermore, reveal the differences from different plant groups (e.g. C3 and C4 plants; annual (A-herbs) and perennial (P-herbs) herbs; conifer, deciduous and evergreen trees) under the same drought intensities. Additionally, we analyzed the relationship between stomatal conductance (Gs) with Pn, Tr and WUE. Our results were as follows: 1) drought decreased the photosynthetic traits with the drought stress increasing, but increased the water use efficiency, and increased to the greatest extent in lianas, compared with herbs, shrubs and trees. 2) Furthermore, C4 plants had an advantage in photosynthesis compared to C3 plants under the same drought conditions. However, the WUE in C4 plants was not promoted as in C3 plants. The photosynthesis traits showed a more substantial decrease in P-herbs than in A-herbs. The drought promoted the WUE in P-herbs, but inhibited it in A-herbs. Compared with conifer and deciduous trees, the photosynthesis traits declined the most in evergreen tree. The WUE in deciduous trees showed a more obvious increase among the three leaf habits. 3) Finally, the Gs showed a close relationship with photosynthesis rate (Pn) and transpiration rate (Tr), which could explain 50% of the

Initial Screening of Thermochemical Water-Splitting Cycles for High Efficiency Generation of Hydrogen Fuels Using Nuclear Power

International Nuclear Information System (INIS)

Brown, L.C.; Funk, J.F.; Showalter, S.K.

1999-01-01

OAK B188 Initial Screening of Thermochemical Water-Splitting Cycles for High Efficiency Generation of Hydrogen Fuels Using Nuclear Power There is currently no large scale, cost-effective, environmentally attractive hydrogen production process, nor is such a process available for commercialization. Hydrogen is a promising energy carrier, which potentially could replace the fossil fuels used in the transportation sector of our economy. Fossil fuels are polluting and carbon dioxide emissions from their combustion are thought to be responsible for global warming. The purpose of this work is to determine the potential for efficient, cost-effective, large-scale production of hydrogen utilizing high temperature heat from an advanced nuclear power station. Almost 800 literature references were located which pertain to thermochemical production of hydrogen from water and over 100 thermochemical watersplitting cycles were examined. Using defined criteria and quantifiable metrics, 25 cycles have been selected for more detailed study

Water use efficiency in a primary subtropical evergreen forest in Southwest China.

Science.gov (United States)

Song, Qing-Hai; Fei, Xue-Hai; Zhang, Yi-Ping; Sha, Li-Qing; Liu, Yun-Tong; Zhou, Wen-Jun; Wu, Chuan-Sheng; Lu, Zhi-Yun; Luo, Kang; Gao, Jin-Bo; Liu, Yu-Hong

2017-02-20

We calculated water use efficiency (WUE) using measures of gross primary production (GPP) and evapotranspiration (ET) from five years of continuous eddy covariance measurements (2009-2013) obtained over a primary subtropical evergreen broadleaved forest in southwestern China. Annual mean WUE exhibited a decreasing trend from 2009 to 2013, varying from ~2.28 to 2.68 g C kg H 2 O -1 . The multiyear average WUE was 2.48 ± 0.17 (mean ± standard deviation) g C kg H 2 O -1 . WUE increased greatly in the driest year (2009), due to a larger decline in ET than in GPP. At the diurnal scale, WUE in the wet season reached 5.1 g C kg H 2 O -1 in the early morning and 4.6 g C kg H 2 O -1 in the evening. WUE in the dry season reached 3.1 g C kg H 2 O -1 in the early morning and 2.7 g C kg H 2 O -1 in the evening. During the leaf emergence stage, the variation of WUE could be suitably explained by water-related variables (relative humidity (RH), soil water content at 100 cm (SWC_100)), solar radiation and the green index (Sgreen). These results revealed large variation in WUE at different time scales, highlighting the importance of individual site characteristics.

Benchmarking the efficiency of the Chilean water and sewerage companies: a double-bootstrap approach.

Science.gov (United States)

Molinos-Senante, María; Donoso, Guillermo; Sala-Garrido, Ramon; Villegas, Andrés

2018-03-01

Benchmarking the efficiency of water companies is essential to set water tariffs and to promote their sustainability. In doing so, most of the previous studies have applied conventional data envelopment analysis (DEA) models. However, it is a deterministic method that does not allow to identify environmental factors influencing efficiency scores. To overcome this limitation, this paper evaluates the efficiency of a sample of Chilean water and sewerage companies applying a double-bootstrap DEA model. Results evidenced that the ranking of water and sewerage companies changes notably whether efficiency scores are computed applying conventional or double-bootstrap DEA models. Moreover, it was found that the percentage of non-revenue water and customer density are factors influencing the efficiency of Chilean water and sewerage companies. This paper illustrates the importance of using a robust and reliable method to increase the relevance of benchmarking tools.

Batteries for Efficient Energy Extraction from a Water Salinity Difference

KAUST Repository

La Mantia, Fabio

2011-04-13

The salinity difference between seawater and river water is a renewable source of enormous entropic energy, but extracting it efficiently as a form of useful energy remains a challenge. Here we demonstrate a device called "mixing entropy battery", which can extract and store it as useful electrochemical energy. The battery, containing a Na2-xMn 5O10 nanorod electrode, was shown to extract energy from real seawater and river water and can be applied to a variety of salt waters. We demonstrated energy extraction efficiencies of up to 74%. Considering the flow rate of river water into oceans as the limiting factor, the renewable energy production could potentially reach 2 TW, or ∼13% of the current world energy consumption. The mixing entropy battery is simple to fabricate and could contribute significantly to renewable energy in the future. © 2011 American Chemical Society.

How to Improve Water Usage Efficiency? Characterization of Family Farms in A Semi-Arid Area

Directory of Open Access Journals (Sweden)

Laura Piedra-Muñoz

2017-10-01

Full Text Available Water scarcity in Spain is partly due to poor management of this resource in the agricultural sector. The main aim of this study is to present the major factors related to water usage efficiency in farming. It focuses on the Almería coast, southeast Spain, which is one of the most arid areas of the country, and in particular, on family farms as the main direct managers of water use in this zone. Many of these farms are among the most water efficient in Spanish agriculture but this efficiency is not generalized throughout the sector. This work conducts a comprehensive assessment of water performance in this area, using on-farm water-use, structural, socio-economic, and environmental information. Two statistical techniques are used: descriptive analysis and cluster analysis. Thus, two groups are identified: farms that are less and farms that are more efficient regarding water usage. By analyzing both the common characteristics within each group and the differences between the groups with a one-way ANOVA analysis, several conclusions can be reached. The main differences between the two clusters center on the extent to which innovation and new technologies are used in irrigation. The most water efficient farms are characterized by more educated farmers, a greater degree of innovation, new irrigation technology, and an awareness of water issues and environmental sustainability. The findings of this study can be extended to farms in similar arid and semi-arid areas and contribute to fostering appropriate policies to improve the efficiency of water usage in the agricultural sector.

Effect of drip irrigation on yield, evapotranspiration and water use efficiency of sweet basil (Ocimum basilicum L.

Directory of Open Access Journals (Sweden)

Pejić Borivoj

2017-01-01

Full Text Available The experiments showing the effect of drip irrigation on yield, evapotranspiration and water productivity of sweet basil (Ocimum basilicum L. were conducted at the experimental field of the Alternative Crops Department, Institute of Field and Vegetable Crops, Novi Sad. Irrigation was scheduled on the basis of the water balance method. Daily evapotranspiration (ETd was computed from the reference evapotranspiration (ETo and crop coefficient (kc in May, June, July and August of 0.5, 0.6, 1.1 and 1.0, respectively. ETo was calculated using Hargreaves equation. The irrigation depth was restricted to the soil depth of 0.3 m. In other words, irrigation started when readily available water in the soil layer of 0.3 m was completely depleted by plants. The irrigation rate was 30 mm (30 l m-2 while the amount of water added by irrigation during the season was 140 mm. Basil sensitivity to water stress was determined using a yield response factor (Ky. According to the results, the yield of fresh herb of basil under irrigation (32.015 t ha-1 was higher by 9% compared to non-irrigated, control variant (29.364 t ha-1. Worthy of note, basil essential oil yield was significantly affected by irrigation (35.329/28.766 kg ha-1. The content of essential oil was significantly higher in irrigated (6.45 g kg-1 than in non-irrigated variant (5.33 g kg-1 in the first harvest, while no significant difference between irrigated and non-irrigated variants was obtained in the second harvest (6.83 and 6.62 g kg-1 , respectively. Water used on evapotranspiration in irrigation conditions (ETm was 431 mm and 270 mm in non-irrigated, control variant (ETa. The values of irrigation water use efficiency (Iwue and evapotranspiration water use efficiency (ETwue were 1.89 kg m-3 and 1.65 kg m-3 respectively. Ky value (0.22 exhibits all essential characteristics of climate conditions of 2016 rainy year. These preliminary results could be used as a good platform for basil growers in the

The Effect of Water Stress and Polymer on Water Use Efficiency, Yield and several Morphological Traits of Sunflower under Greenhouse Condition

Directory of Open Access Journals (Sweden)

Hossein NAZARLI

2010-12-01

Full Text Available In many part of Iran, the reproductive growth stages of sunflower (Helianthus annuus L. are exposed to water deficit stress. Therefore, the investigation of irrigation management in the farm conditions is a necessary element for increasing irrigation efficiency and decreasing water losses. The objective of present study was to investigate the effect of different rates of super absorbent polymer and levels of water stress on water use efficiency (WUE, yield and some morphological traits of sunflower (cultivar Master. Factorial experiment was carried out in completely randomized design with 3 replications. Factors were water stress in three levels (irrigation in 0.75; 0.50 and 0.25% of field capacity and super absorbent polymer in five levels (0; 0.75; 0.150; 2.25; 3 g/kg of soil. Super absorbent polymer was added in eight leaves stage of sunflower to pots in deepness of roots development. Water stress treatment was also applied in this growth stage of sunflower. For stress application, pots were weighted every day and irrigated when soil water received to 0.75; 0.50 and 0.25 of field capacity, respectively. The results of ANOVA indicated that the effect of different rates of super absorbent polymer and different rates of consumed water in all traits were significant. ANOVA also revealed that the interactive effects of two mentioned factors were significant except for seed yield trait. Polynomial model based on the ANOVA results was fitted for each trait. The results indicated that water stress significantly convert in decreasing the number of leaves per plant, chlorophyll content, 100 weight of seeds, seed yield and WUE in sunflower, whereas the application of super absorbent polymer moderated the negative effect of deficit irrigation, especially in high rates of polymer (2.25 and 3 g/kg of soil. The above mentioned rates of polymer have the best effect to all characteristics of sunflower in all levels of water stress treatment. The findings

Strobilurin fungicides induce changes in photosynthetic gas exchange that do not improve water use efficiency of plants grown under conditions of water stress.

Science.gov (United States)

Nason, Mark A; Farrar, John; Bartlett, David

2007-12-01

The effects of five strobilurin (beta-methoxyacrylate) fungicides and one triazole fungicide on the physiological parameters of well-watered or water-stressed wheat (Triticum aestivum L.), barley (Hordeum vulgare L.) and soya (Glycine max Merr.) plants were compared. Water use efficiency (WUE) (the ratio of rate of transpiration, E, to net rate of photosynthesis, A(n)) of well-watered wheat plants was improved slightly by strobilurin fungicides, but was reduced in water-stressed plants, so there is limited scope for using strobilurins to improve the water status of crops grown under conditions of drought. The different strobilurin fungicides had similar effects on plant physiology but differed in persistence and potency. When applied to whole plants using a spray gun, they reduced the conductance of water through the epidermis (stomatal and cuticular transpiration), g(sw), of leaves. Concomitantly, leaves of treated plants had a lower rate of transpiration, E, a lower intercellular carbon dioxide concentration, c(i), and a lower net rate of photosynthesis, A(n), compared with leaves of control plants or plants treated with the triazole. The mechanism for the photosynthetic effects is not known, but it is hypothesised that they are caused either by strobilurin fungicides acting directly on ATP production in guard cell mitochondria or by stomata responding to strobilurin-induced changes in mesophyll photosynthesis. The latter may be important since, for leaves of soya plants, the chlorophyll fluorescence parameter F(v)/F(m) (an indication of the potential quantum efficiency of PSII photochemistry) was reduced by strobilurin fungicides. It is likely that the response of stomata to strobilurin fungicides is complex, and further research is required to elucidate the different biochemical pathways involved. Copyright (c) 2007 Society of Chemical Industry.

Response of Cotton to Irrigation Methods and Nitrogen Fertilization: Yield Components, Water-Use Efficiency, Nitrogen Uptake, and Recovery

International Nuclear Information System (INIS)

Janat, M.

2009-01-01

Efficient crop use of nitrogen (N) fertilizer is critical from economic and environmental viewpoints, especially under irrigated conditions. Cotton yield parameters, fiber quality, water- and N-use efficiency responses to N, and irrigation methods in northern Syria were evaluated. Field trials were conducted for two growing seasons on a Chromoxerertic Rhodoxeralf soil. Treatments consisted of drip fertigation, furrow irrigation, and five different rates of N fertilizer (50, 100, 150, 200, and 250 kg N /ha). Cotton was irrigated when soil moisture in the specified active root depth was 80% of the field capacity as indicated by the neutron probe. Seed cotton yield was higher than the national average (3,928 kg/ha) by at least 12% as compared to all treatments. Lint properties were not negatively affected by the irrigation method or N rates. Water savings under drip fertigation ranged between 25 and 50% of irrigation water relative to furrow irrigation. Crop water-use efficiencies of the drip-fertigated treatments were in most cases 100% higher than those of the corresponding furrow-irrigated treatments. The highest water demand was during the fruit-setting growth stage. It was also concluded that under drip fertigation, 100 -150 N kg/ha was adequate and comparable with the highest N rates tested under furrow irrigation regarding lint yield, N uptake, and recovery. Based on cotton seed yield and weight of stems, the overall amount of N removed from the field for the drip-fertigated treatments ranged between 101-118 kg and 116-188 N/ha for 2001 and 2002, respectively. The N removal ranged between 94-113 and 111-144 kg N/ha for the furrow-irrigated treatments for 2001 and 2002, respectively. (author)

Analysis of water and nitrogen use efficiency for maize (Zea mays L.) grown on soft rock and sand compound soil.

Science.gov (United States)

Wang, Huanyuan; Han, Jichang; Tong, Wei; Cheng, Jie; Zhang, Haiou

2017-06-01

Maize was grown on compound soils constituted from mixtures of soft rock and sand at different ratios, and water use efficiency (WUE), nitrogen use efficiency (NUE) and fertilizer nitrogen use efficiency (FNUE) were quantified. The data were used to assist in designing strategies for optimizing water and nitrogen management practices for maize on the substrates used. Maize was sown in composite soil prepared at three ratios of soft rock and sand (1:1, 1:2 and 1:5 v/v) in Mu Us Sandy Land, Yuyang district, Yulin city, China. Yields, amount of drainage, nitrogen (N) leaching, WUE and NUE were calculated. Then a water and nitrogen management model (WNMM) was calibrated and validated. No significant difference in evapotranspiration of maize was found among compound soils with soft rock/sand ratios of 1:1, 1:2 and 1:5, while water drainage increased significantly with increasing soft rock/sand ratio. WUE increased to 1.30 kg m -3 in compound soil with 1:2 soft rock/sand ratio. Nitrogen leaching and ammonia volatilization were the main reason for nitrogen loss, and N reduction mainly relied on crop uptake. NUE and FNUE could reach 33.1 and 24.9 kg kg -1 N respectively. Water drainage and nitrogen leaching occurred mostly during heavy rainfall or irrigation. Through a scenario analysis of different rainfall types, water and fertilizer management systems were formulated each year. This study shows that soft rock plays a key role in improving the WUE, NUE and FNUE of maize. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

Clonal variability for water use efficiency and carbon isotope discrimination ( 13C) in selected clones of a few Eucalyptus species

CSIR Research Space (South Africa)

Mohan Raju, B

2011-11-01

Full Text Available and develop high water use efficient clones to cultivate under water limited environments. The major objective was to assess the eucalyptus clones for variability in WUE and to determine the relationship between WUE and carbon isotope discrimination ( 13C...

Herbivory mitigation through increased water-use efficiency in a leaf-mining moth-apple tree relationship.

Science.gov (United States)

Pincebourde, Sylvain; Frak, Ela; Sinoquet, Hervé; Regnard, Jean Luc; Casas, Jérôme

2006-12-01

Herbivory alters plant gas exchange but the effects depend on the type of leaf damage. In contrast to ectophagous insects, leaf miners, by living inside the leaf tissues, do not affect the integrity of the leaf surface. Thus, the effect of leaf miners on CO2 uptake and water-use efficiency by leaves remains unclear. We explored the impacts of the leaf-mining moth Phyllonorycter blancardella (Lepidoptera: Gracillariidae) on light responses of the apple leaf gas exchanges to determine the balance between the negative effects of reduced photosynthesis and potential positive impacts of increased water-use efficiency (WUE). Gas exchange in intact and mined leaf tissues was measured using an infrared gas analyser. The maximal assimilation rate was slightly reduced but the light response of net photosynthesis was not affected in mined leaf tissues. The transpiration rate was far more affected than the assimilation rate in the mine integument as a result of stomatal closure from moderate to high irradiance level. The WUE was about 200% higher in the mined leaf tissues than in intact leaf portions. Our results illustrate a novel mechanism by which plants might minimize losses from herbivore attacks; via trade-offs between the negative impacts on photosynthesis and the positive effects of increased WUE.

Water and radiation use efficiencies of transplanted rice (Oryza sativa L.) at different plant densities and irrigation regimes under semi-arid environment

International Nuclear Information System (INIS)

Ahmad, S.; Ali, H.; Shad, S.A.; Zia-ul-Haq, M.; Ahmad, A.; Maqsood, M.; Khan, M.B.; Mehmood, S.; Hussain, A.

2008-01-01

Growth and yield of rice (Oryza sativa L.), in response to plant densities and irrigation (optimum to stress) were analyzed in terms of interception and utilization of photo-synthetically active radiation (PAR) and water use efficiency (WUE). The amount of PAR intercepted and cumulative evapotranspiration (ET) by each treatment was estimated from the measured leaf area index. The relationships between total dry matter grain yield and accumulated intercepted PAR and cumulative ET were linear. Yield differences among the treatments were attributed to the amount of PAR intercepted and water transpired their efficiencies of utilization or both. The fraction of intercepted radiation and WUE was significantly affected by the plant densities and various irrigation regimes, while, radiation utilization efficiency (RUE) and water use efficiency (WUE) for TDM varied from 1.15 g MJ-1 to 1.36 g MJ-1 and 22.6 kg per ha mm-1 to 24.3 kg per ha mm-1 during both the seasons

Photocatalytic efficiency of titania photocatalysts in saline waters

Directory of Open Access Journals (Sweden)

Albrbar Asma Juma

2014-01-01

Full Text Available The photocatalytic efficiency of the recently synthesized TiO2 powder, named P160, of the degradation of dye Dye C.I. Reactive orange 16 in natural and artificial seawater was investigated in comparison to its efficiency in deionized water and the efficiency of a standard TiO2 powder Degusa P25. It was shown that the photocatalytic efficiency of P160 was slightly higher than that of P25, probably due to slightly higher specific surface area, higher pore volume and larger pores of the powder P160. The efficiency of both photocatalysts in natural and artificial seawater was significantly lower than that in deionized water. The overall rate of dye degradation for both types of photocatalysts is litle higher in artificial seawater than in natural seawater, which shows the influence of organic compounds naturally present in seawater on the photocatalysts activity. A saturation Langmuir-type relationship between the initial degradation rate and the initial dye concentration indicates that the adsorption plays a role in the photocatalytic reaction. The photodegradation rate constant k, which represents the maximum reaction rate, has similar values for P25 and P160 in all types of water due to the similar properties of the photocatalysts. [Projekat Ministarstva nauke Republike Srbije, br III 45019

Stable carbon isotope ratios and intrinsic water-use efficiency of Miocene fossil leaves compared to modern congeners

Energy Technology Data Exchange (ETDEWEB)

Marshall, J.D.; Zhang, J.; Rember, W.C.; Jennings, D.; Larson, P. (Univ. of Idaho, Moscow, ID (United States))

1994-06-01

Miocene fossil leaves of forest trees were extracted from the Clarkia, Idaho fossil beds and their stable carbon isotope ratios were analyzed. Fossils had higher lignin concentrations and lower cellulose concentrations that modern leaves due to diagenesis and the HF used to extract the fossils. Therefore, [delta][sup 13]C of extracted fossil lignin was compared to that of modern lignin. Fossil lignin [delta][sup 13]C was significantly different from that of congeneric modern leaves (paired t-test, P<0.0001), but was 1.9% less negative. Gymnosperms (Metasequoia, Taxodium) were less negative than angiosperms (e.g., Magnolia, Quercus, Acer, Persea), but no difference between evergreen and deciduous species was detected. Using published estimates of the concentration and [delta][sup 13]C of atmospheric CO[sub 2] during the Miocene was estimated the CO[sub 2] partial pressure gradient across the stomata (intrinsic water-use efficiency). Intrinsic water-use efficiency was at least 70% higher during this past [open quotes]greenhouse[close quotes] period than at present.

Photosynthetic capacity and intrinsic water-use efficiency of Rhizophora mangle at its southernmost western Atlantic range

Science.gov (United States)

M.L.G. Soares; M.M.P. Tognella; E. Cuevas; E. Medina

2015-01-01

The southernmost presence of Rhizophora mangle in the western Atlantic coast occurs in coastal wetlands between 27 and 28ºS in the State of Santa Catarina, Brazil. We selected mangrove communities at the estuary of Rio Tavares, Florianopolis, and Sonho Beach, Palhosa, for measurement of photosynthetic performance and intrinsic water use efficiency of R. mangle and...

Land use efficiency: anticipating future demand for land-sector greenhouse gas emissions abatement and managing trade-offs with agriculture, water, and biodiversity.

Science.gov (United States)

Bryan, Brett A; Crossman, Neville D; Nolan, Martin; Li, Jing; Navarro, Javier; Connor, Jeffery D

2015-11-01

Competition for land is increasing, and policy needs to ensure the efficient supply of multiple ecosystem services from land systems. We modelled the spatially explicit potential future supply of ecosystem services in Australia's intensive agricultural land in response to carbon markets under four global outlooks from 2013 to 2050. We assessed the productive efficiency of greenhouse gas emissions abatement, agricultural production, water resources, and biodiversity services and compared these to production possibility frontiers (PPFs). While interacting commodity markets and carbon markets produced efficient outcomes for agricultural production and emissions abatement, more efficient outcomes were possible for water resources and biodiversity services due to weak price signals. However, when only two objectives were considered as per typical efficiency assessments, efficiency improvements involved significant unintended trade-offs for the other objectives and incurred substantial opportunity costs. Considering multiple objectives simultaneously enabled the identification of land use arrangements that were efficient over multiple ecosystem services. Efficient land use arrangements could be selected that meet society's preferences for ecosystem service provision from land by adjusting the metric used to combine multiple services. To effectively manage competition for land via land use efficiency, market incentives are needed that effectively price multiple ecosystem services. © 2015 John Wiley & Sons Ltd.

Nitrogen use efficiency evaluation of aerobic rice under field capacity water potential using {sup 15}N isotopic tracer technique

Energy Technology Data Exchange (ETDEWEB)

Wahid, Ahmad Nazrul Abd, E-mail: a-nazrul@nuclearmalaysia.gov.my [Faculty of Science and Technology, Universiti Kebangsaan Malaysia, Bangi, 43600, Selangor (Malaysia); Malaysian Nuclear Agency, Bangi, 43000 Kajang, Selangor (Malaysia); Rahim, Sahibin Abd, E-mail: haiyan@ukm.edu.my [Faculty of Science and Technology, Universiti Kebangsaan Malaysia, Bangi, 43600, Selangor (Malaysia); Rahim, Khairuddin Abdul; Harun, Abdul Rahim [Malaysian Nuclear Agency, Bangi, 43000 Kajang, Selangor (Malaysia)

2015-09-25

This study was carried out to evaluate the efficiency use of the nitrogen fertilizer on aerobic rice varieties MR219-4 and MR219-9 which were grown aerobically under field capacity water potential at the controlled environment area or shield house. Direct {sup 15}N isotope tracer method was used in this study, whereby the {sup 15}N isotope was utilized as a tracer for nitrogen nutrient uptake. {sup 15}N isotope presence in the samples is determined by using emission spectrometer analysis and percentage of total nitrogen is determined by using Kjeldahl method. {sup 15}N atom access value contained in the sample will be used in determining the effectiveness of the use of nitrogen in fertilizers through the specific calculation formulas. In this work, the data several data of nitrogen derived from fertilizer (Ndff), total nitrogen, nitrogen uptake and nitrogen use efficiency was obtained.

The diversity of (13)C isotope discrimination in a Quercus robur full-sib family is associated with differences in intrinsic water use efficiency, transpiration efficiency, and stomatal conductance.

Science.gov (United States)

Roussel, Magali; Dreyer, Erwin; Montpied, Pierre; Le-Provost, Grégoire; Guehl, Jean-Marc; Brendel, Oliver

2009-01-01

(13)C discrimination in organic matter with respect to atmospheric CO(2) (Delta(13)C) is under tight genetic control in many plant species, including the pedunculate oak (Quercus robur L.) full-sib progeny used in this study. Delta(13)C is expected to reflect intrinsic water use efficiency, but this assumption requires confirmation due to potential interferences with mesophyll conductance to CO(2), or post-photosynthetic discrimination. In order to dissect the observed Delta(13)C variability in this progeny, six genotypes that have previously been found to display extreme phenotypic values of Delta(13)C [either very high ('high Delta') or low ('low Delta') phenotype] were selected, and transpiration efficiency (TE; accumulated biomass/transpired water), net CO(2) assimilation rate (A), stomatal conductance for water vapour (g(s)), and intrinsic water use efficiency (W(i)=A/g(s)) were compared with Delta(13)C in bulk leaf matter, wood, and cellulose in wood. As expected, 'high Delta' displayed higher values of Delta(13)C not only in bulk leaf matter, but also in wood and cellulose. This confirmed the stability of the genotypic differences in Delta(13)C recorded earlier. 'High Delta' also displayed lower TE, lower W(i), and higher g(s). A small difference was detected in photosynthetic capacity but none in mesophyll conductance to CO(2). 'High Delta' and 'low Delta' displayed very similar leaf anatomy, except for higher stomatal density in 'high Delta'. Finally, diurnal courses of leaf gas exchange revealed a higher g(s) in 'high Delta' in the morning than in the afternoon when the difference decreased. The gene ERECTA, involved in the control of water use efficiency, leaf differentiation, and stomatal density, displayed higher expression levels in 'low Delta'. In this progeny, the variability of Delta(13)C correlated closely with that of W(i) and TE. Genetic differences of Delta(13)C and W(i) can be ascribed to differences in stomatal conductance and stomatal

Radiation and water use efficiencies of two coniferous forest canopies

Science.gov (United States)

Lamaud, E.; Brunet, Y.; Berbigier, P.

1996-12-01

Two experiments were performed in a confierous forest (maritime pine) in the southwest of France, one in 1994 and the other in 1995. Two sites were chosen, differing by age, height and structure of the trees, as well as the nature of the understorey. In both cases measurements of turbulent fluxes were made at two levels above and within the forest canopy, using sonic anemometers and open-path infrared CO 2-H 2O analysers. The flux differences derived from the two measurement levels allowed the Radiation and Water Use Efficiencies (RUE and WUE, respectively) to be evaluated for both canopy crowns. The results are based on the analysis of about ten days from each experiment. For both campaigns RUE is significantly larger during cloudy conditions when the fraction of diffuse radiation ( {Q id}/{Q i}) increases. An empirical linear relation between RUE and {Q id}/{Q i} is established for each site, with a smaller intercept and a larger slope for the older forest. In clear conditions ( {Q id}/{Q i} < 0.4 ), RUE is about 30 % lower for this forest. Tree photosynthesis, estimated as the net CO 2 flux of the foliated layer F c, appears poorly correlated (r 2 < 0.4) with transpiration (net water vapour flux E). This is shown to result from strong variations in the atmospheric saturation deficit D during both campaigns. At both sites WUE turns out to be a hyperbolic function of D ( {Fc}/{E} = {-k}/{D}). The coefficient k is 50 % larger for the younger forest. This is in agreement with the values obtained for RUE, and indicates that photosynthetic rates decrease with the age of the trees.

Dynamic water allocation policies improve the global efficiency of storage systems

Science.gov (United States)

Niayifar, Amin; Perona, Paolo

2017-06-01

Water impoundment by dams strongly affects the river natural flow regime, its attributes and the related ecosystem biodiversity. Fostering the sustainability of water uses e.g., hydropower systems thus implies searching for innovative operational policies able to generate Dynamic Environmental Flows (DEF) that mimic natural flow variability. The objective of this study is to propose a Direct Policy Search (DPS) framework based on defining dynamic flow release rules to improve the global efficiency of storage systems. The water allocation policies proposed for dammed systems are an extension of previously developed flow redistribution rules for small hydropower plants by Razurel et al. (2016).The mathematical form of the Fermi-Dirac statistical distribution applied to lake equations for the stored water in the dam is used to formulate non-proportional redistribution rules that partition the flow for energy production and environmental use. While energy production is computed from technical data, riverine ecological benefits associated with DEF are computed by integrating the Weighted Usable Area (WUA) for fishes with Richter's hydrological indicators. Then, multiobjective evolutionary algorithms (MOEAs) are applied to build ecological versus economic efficiency plot and locate its (Pareto) frontier. This study benchmarks two MOEAs (NSGA II and Borg MOEA) and compares their efficiency in terms of the quality of Pareto's frontier and computational cost. A detailed analysis of dam characteristics is performed to examine their impact on the global system efficiency and choice of the best redistribution rule. Finally, it is found that non-proportional flow releases can statistically improve the global efficiency, specifically the ecological one, of the hydropower system when compared to constant minimal flows.

On eco-efficient technologies to minimize industrial water consumption

Science.gov (United States)

Amiri, Mohammad C.; Mohammadifard, Hossein; Ghaffari, Ghasem

2016-07-01

Purpose - Water scarcity will further stress on available water systems and decrease the security of water in many areas. Therefore, innovative methods to minimize industrial water usage and waste production are of paramount importance in the process of extending fresh water resources and happen to be the main life support systems in many arid regions of the world. This paper demonstrates that there are good opportunities for many industries to save water and decrease waste water in softening process by substituting traditional with echo-friendly methods. The patented puffing method is an eco-efficient and viable technology for water saving and waste reduction in lime softening process. Design/methodology/approach - Lime softening process (LSP) is a very sensitive process to chemical reactions. In addition, optimal monitoring not only results in minimizing sludge that must be disposed of but also it reduces the operating costs of water conditioning. Weakness of the current (regular) control of LSP based on chemical analysis has been demonstrated experimentally and compared with the eco-efficient puffing method. Findings - This paper demonstrates that there is a good opportunity for many industries to save water and decrease waste water in softening process by substituting traditional method with puffing method, a patented eco-efficient technology. Originality/value - Details of the required innovative works to minimize industrial water usage and waste production are outlined in this paper. Employing the novel puffing method for monitoring of lime softening process results in saving a considerable amount of water while reducing chemical sludge.

High efficient ammonia heat pump system for industrial process water using the ISEC concept. Part 2

DEFF Research Database (Denmark)

Olesen, Martin F.; Madsen, Claus; Olsen, Lars

2014-01-01

The Isolated System Energy Charging (ISEC) concept allows for a high efficiency of a heat pump system for hot water production. The ISEC concept consists of two water storage tanks, one charged and one discharged. The charged tank is used for the industrial process, while the discharged tank...... is charging. The charging of the tank is done by recirculating water through the condenser and thereby gradually heating the water. The modelling of the system is described in Part I [1]. In this part, Part II, an experimental test setup of the tank system is reported, the results are presented and further...... modelling of the heat pump and tank system is performed (in continuation of Part I). The modelling is extended to include the system performance with different natural refrigerants and the influence of different types of compressors....

Boron removal efficiency from Red Sea water using different SWRO/BWRO membranes

KAUST Repository

Rahmawati, Karina; Ghaffour, NorEddine; Aubry, Cyril; Amy, Gary L.

2012-01-01

Seawater reverse osmosis (SWRO) desalination process provides high quality of fresh water. However, due to some operational constraints mainly scaling control some trace contaminant removal, such as acceptable boron concentration, cannot be achieved in a single pass SWRO system. The objective of this study was to investigate the efficiency of five difference reverse osmosis (RO) membranes (seawater SW and brackish water BW) provided by different manufacturers for boron removal. RO experiments using pretreated real Red Sea water were conducted in parallel to compare membrane performance under the same operating conditions. As expected, results showed that boron rejection increased as the feed pH increased. This was caused by dissociation of boric acid to negatively charged borate ions and more negatively charged membrane surface at elevated pH which enhanced boron rejection. Single pass RO system, with and without elevating the pH, may not be sufficient for two reasons. First, boron concentration in permeate does not fulfill local regulations (<0.5ppm). Second, severe scaling occurs due to operation in alkaline condition, since Ca 2+ and Mg 2+ concentrations are still high to cause salts precipitation. Techno-economical study was performed to select the best configuration and membrane giving the highest performance in terms of boron and TDS rejections and energy consumption. © 2012 Elsevier B.V.

Boron removal efficiency from Red Sea water using different SWRO/BWRO membranes

KAUST Repository

Rahmawati, Karina

2012-12-01

Seawater reverse osmosis (SWRO) desalination process provides high quality of fresh water. However, due to some operational constraints mainly scaling control some trace contaminant removal, such as acceptable boron concentration, cannot be achieved in a single pass SWRO system. The objective of this study was to investigate the efficiency of five difference reverse osmosis (RO) membranes (seawater SW and brackish water BW) provided by different manufacturers for boron removal. RO experiments using pretreated real Red Sea water were conducted in parallel to compare membrane performance under the same operating conditions. As expected, results showed that boron rejection increased as the feed pH increased. This was caused by dissociation of boric acid to negatively charged borate ions and more negatively charged membrane surface at elevated pH which enhanced boron rejection. Single pass RO system, with and without elevating the pH, may not be sufficient for two reasons. First, boron concentration in permeate does not fulfill local regulations (<0.5ppm). Second, severe scaling occurs due to operation in alkaline condition, since Ca 2+ and Mg 2+ concentrations are still high to cause salts precipitation. Techno-economical study was performed to select the best configuration and membrane giving the highest performance in terms of boron and TDS rejections and energy consumption. © 2012 Elsevier B.V.

Evaluation of Intrinsic Water Use Efficiency and Ecophysiological Modelling on a Potato Dihaploid Mapping Population

DEFF Research Database (Denmark)

Topbjerg, Henrik Bak

of the solution the crop has to be able to tolerate drought. In this study, a dihaploid potato mapping population has been used to investigate clonal performance in intrinsic water use efficiency (WUEi) under progressive drought achieved in greenhouse and under field conditions. The mapping population revealed...... on environmental sustainability. Future growth in the global population predicts that the agricultural output will have to increase considerably if malnutrition and famine are to be prevented. On this basis, the development of crops capable of producing higher yields under water scarce situations is being...... progression in the development of drought tolerant crop cultivars, faster screening methods have to be developed. Here, it was found that the chlorophyll content index could be a useful screening method for higher WUEi under greenhouse conditions. However, such methods must rely on physiological trait...

Water use characteristics of a bambara groundnut ( Vigna ...

African Journals Online (AJOL)

Bambara groundnut is slow to establish and this has negative implications for total water use. Consideration of bambara groundnut as a water-efficient crop for dry areas will benefit from an understanding of water use efficiency and water use characteristics during establishment. We investigated whether there is an ...

Water use efficiency of tomatoes - in greenhouses and hydroponics

NARCIS (Netherlands)

Nederhoff, E.M.; Stanghellini, C.

2010-01-01

Massive amounts of water are required for the production of our food, varying from several cubic metres per kilogram of beef to as low as 4 litres per kilogram for tomatoes grown in high-tech glasshouses. This article presents data on Product Water Use (PWU) of some foods and discusses how the water

Water in blast holes can improve blasting efficiency and cut costs

Energy Technology Data Exchange (ETDEWEB)

O' Regan, G.

1983-08-01

Water in blast holes has been a traditional problem faced by blasting engineers and foremen in surface mining. Presently accepted techniques for blasting in water-filled holes include the use of more expensive water-gel explosives which are denser than water, dewatering of holes by pumping, and blowing out the water with a small charge before loading the main ANFO charge column. These methods involve considerable expense and delay to the normal charge-loading procedure. The author describes a method of using the water in blast holes to improve blasting efficiency and reduce the consumption of explosive.

Best Practices for Water Conservation and Efficiency as an Alternative for Water Supply Expansion

Science.gov (United States)

EPA released a document that provides water conservation and efficiency best practices for evaluating water supply projects. The document can help water utilities and federal and state governments carry out assessments of the potential for future

Interaction of CO2 concentrations and water stress in semiarid plants causes diverging response in instantaneous water use efficiency and carbon isotope composition

Science.gov (United States)

Zhao, Na; Meng, Ping; He, Yabing; Yu, Xinxiao

2017-07-01

In the context of global warming attributable to the increasing levels of CO2, severe drought may be more frequent in areas that already experience chronic water shortages (semiarid areas). This necessitates research on the interactions between increased levels of CO2 and drought and their effect on plant photosynthesis. It is commonly reported that 13C fractionation occurs as CO2 gas diffuses from the atmosphere to the substomatal cavity. Few researchers have investigated 13C fractionation at the site of carboxylation to cytoplasm before sugars are exported outward from the leaf. This process typically progresses in response to variations in environmental conditions (i.e., CO2 concentrations and water stress), including in their interaction. Therefore, saplings of two typical plant species (Platycladus orientalis and Quercus variabilis) from semiarid areas of northern China were selected and cultivated in growth chambers with orthogonal treatments (four CO2 concentration ([CO2]) × five soil volumetric water content (SWC)). The δ13C of water-soluble compounds extracted from leaves of saplings was determined for an assessment of instantaneous water use efficiency (WUEcp) after cultivation. Instantaneous water use efficiency derived from gas-exchange measurements (WUEge) was integrated to estimate differences in δ13C signal variation before leaf-level translocation of primary assimilates. The WUEge values in P. orientalis and Q. variabilis both decreased with increased soil moisture at 35-80 % of field capacity (FC) and increased with elevated [CO2] by increasing photosynthetic capacity and reducing transpiration. Instantaneous water use efficiency (iWUE) according to environmental changes differed between the two species. The WUEge in P. orientalis was significantly greater than that in Q. variabilis, while an opposite tendency was observed when comparing WUEcp between the two species. Total 13C fractionation at the site of carboxylation to cytoplasm before sugar

Income and irrigation water use efficiency under climate change: An application of spatial stochastic crop and water allocation model to Western Uzbekistan

Directory of Open Access Journals (Sweden)

Ihtiyor Bobojonov

2016-01-01

Results show farmers’ income could fall by as much as 25% with a 3.2 °C temperature increase and a 15% decline in irrigation. Farmers located in the tail end of the irrigation system could lose an even greater share of their revenues. A more conservative increase in temperature could increase farmer income by as much as 46% with a 2.2° temperature increase and only 8% decline in irrigation water since some crops benefit from extended vegetation periods. Under both pessimistic and optimistic scenarios, environmental challenges due to shallow groundwater tables may improve associated with enhanced water use efficiency.

Stomatal density and metabolic determinants mediate salt stress adaptation and water use efficiency in basil (Ocimum basilicum L.).

Science.gov (United States)

Barbieri, Giancarlo; Vallone, Simona; Orsini, Francesco; Paradiso, Roberta; De Pascale, Stefania; Negre-Zakharov, Florence; Maggio, Albino

2012-11-15

Increasing salinity tolerance and water-use efficiency in crop plants are two major challenges that agriculture must face in the next decades. Many physiological mechanisms and molecular components mediating crop response to environmental stresses have been identified. However, the functional inter-links between stress adaptation responses have not been completely understood. Using two basil cultivars (Napoletano and Genovese) with contrasting ability to respond to salt stress, here we demonstrate that reduced stomatal density, high ascorbate level and polyphenol oxidase (PPO) activity coordinately contribute to improve basil adaptation and water use efficiency (WUE) in saline environment. The constitutively reduced stomatal density was associated with a "delayed" accumulation of stress molecules (and growth inhibiting signals) such as abscisic acid (ABA) and proline, in the more tolerant Genovese. Leaf volatile profiling also revealed cultivar-specific patterns, which may suggest a role for the volatile phenylpropanoid eugenol and monoterpenes in conferring stress tolerance via antioxidant and signalling functions. Copyright © 2012 Elsevier GmbH. All rights reserved.

Uncertainty of wheat water use

NARCIS (Netherlands)

Cammarano, Davide; Rötter, Reimund P.; Asseng, Senthold; Ewert, Frank; Wallach, Daniel; Martre, Pierre; Hatfield, Jerry L.; Jones, James W.; Rosenzweig, Cynthia; Ruane, Alex C.; Boote, Kenneth J.; Thorburn, Peter J.; Kersebaum, Kurt Christian; Aggarwal, Pramod K.; Angulo, Carlos; Basso, Bruno; Bertuzzi, Patrick; Biernath, Christian; Brisson, Nadine; Challinor, Andrew J.; Doltra, Jordi; Gayler, Sebastian; Goldberg, Richie; Heng, Lee; Hooker, Josh E.; Hunt, Leslie A.; Ingwersen, Joachim; Izaurralde, Roberto C.; Müller, Christoph; Kumar, Soora Naresh; Nendel, Claas; O'Leary, Garry; Olesen, Jørgen E.; Osborne, Tom M.; Priesack, Eckart; Ripoche, Dominique; Steduto, Pasquale; Stöckle, Claudio O.; Stratonovitch, Pierre; Streck, Thilo; Supit, Iwan; Tao, Fulu; Travasso, Maria; Waha, Katharina; White, Jeffrey W.; Wolf, Joost

2016-01-01

Projected global warming and population growth will reduce future water availability for agriculture. Thus, it is essential to increase the efficiency in using water to ensure crop productivity. Quantifying crop water use (WU; i.e. actual evapotranspiration) is a critical step towards this goal.

Energy efficiency in a water supply system:Energy consumption and CO2 emission

Institute of Scientific and Technical Information of China (English)

Helena M.RAMOS; Filipe VIEIRA; Didia I.C.COVAS

2010-01-01

This paper presents important fundamentals associated with water and energy efficiency and highlights the importance of using renewable energy sources.A model of multi-criteria optimization for energy efficiency based on water and environmental management policies,including the preservation of water resources and the control of water pressure and energy consumption through a hybrid energy solution,was developed and applied to a water supply system.The methodology developed includes three solutions:(1)the use of a water turbine in pipe systems where pressures are higher than necessary and pressure-reducing valves are installed,(2)the optimization of pumping operation according to the electricity tariff and water demand,and(3)the use of other renewable energy sources,including a wind turbine,to supply energy to the pumping station,with the remaining energy being sold to the national electric grid.The use of an integrated solution(water and energy)proves to be a valuable input for creating benefits from available hydro energy in the water supply system in order to produce clean power,and the use of a wind source allows for the reduction of energy consumption in pumping stations,as well as of the CO2 emission to the atmosphere.

Review of 'plant available water' aspects of water use efficiency ...

African Journals Online (AJOL)

... enhanced understanding of the system, thereby enabling the formulation of a quantitative model relating the water supply from a layered soil profile to water demand; the formulation of logical quantitative definitions for crop-ecotope specific upper and lower limits of available water; the identification of the harmful rootzone ...

Assessment of productivity and water use efficiency in three maize (zea mays L.) varieties in Kwabenya-Atomic area

International Nuclear Information System (INIS)

Frimpong, J. O.

2010-06-01

The production of rain-fed maize in the Kwabenya-Atomic area of the coastal savannah environment of Ghana is limited by low and erratic rainfall. Enhancing maize production in the area will require the use of maize varieties efficient in the use of soil moisture. The study was, therefore, conducted to evaluate three recently released maize varieties (Obatanpa, Mamaba, and Golden Crystal) for their efficiency in the use of soil moisture for total dry matter and grain production and consequently identify the maize varieties suitable for rain-fed production in the Kwabenya-Atomic area. Field experiments were conducted m 2008 during the major and minor cropping seasons at Kwabenya-Atomic area in Ghana using three maize varieties grown at a planting distance of 0.4 m within rows and 0.8 m between rows. The experimental design used was the randomised complete block design in four replicates. Plants were sampled every two weeks throughout the maize growing seasons. Access tubes installed in each sub-plot facilitated simultaneous moisture monitoring with the aid of a neutron probe (CPN (R) 503 Hydroprobe) in a 120 cm soil profile. The moisture content values were used for the estimation of actual evapotranspiration of the maize crop using the water balance approach. Grain yield (GY) and its associated water use efficiency (WUE GY ) were significantly different (P ≤ 0.05) among the maize varieties during the major cropping season with Mamaba producing the highest grain yield of 7250.0 kg ha -1 and WUE GY of 13.2 kg ha -1 mm -1 . For the minor cropping season, no significant difference was observed in grain yield, which ranged between 5800.0 and 7200.0 kg ha -1 , with Obatanpa producing the highest grain yield. No significant difference was observed in WUE GY during the minor cropping season which ranged between 14.6 and 19.1 kg ha -1 mm -1 with Obatanpa having the highest WUE GY . The maize genotype produced similar total dry matter (TDM) during each of the cropping

Improving the ecohydrological and economic efficiency of Small Hydropower Plants with water diversion

Science.gov (United States)

Razurel, Pierre; Gorla, Lorenzo; Tron, Stefania; Niayifar, Amin; Crouzy, Benoît; Perona, Paolo

2018-03-01

Water exploitation for energy production from Small Hydropower Plant (SHP) is increasing despite human pressure on freshwater already being very intense in several countries. Preserving natural rivers thus requires deeper understanding of the global (i.e., ecological and economic) efficiency of flow-diversion practice. In this work, we show that the global efficiency of SHP river intakes can be improved by non-proportional flow-redistribution policies. This innovative dynamic water allocation defines the fraction of water released to the river as a nonlinear function of river runoff. Three swiss SHP case studies are considered to systematically test the global performance of such policies, under both present and future hydroclimatic regimes. The environmental efficiency is plotted versus the economic efficiency showing that efficient solutions align along a (Pareto) frontier, which is entirely formed by non-proportional policies. On the contrary, other commonly used distribution policies generally lie below the Pareto frontier. This confirms the existence of better policies based on non-proportional redistribution, which should be considered in relation to implementation and operational costs. Our results recommend abandoning static (e.g., constant-minimal-flow) policies in favour of non-proportional dynamic ones towards a more sustainable use of the water resource, also considering changing hydroclimatic scenarios.

Evaluation Effects of Different Planting Systems on Water Use Efficiency, Relative Water Content and some Plant Growth Parameters in Onion (Allium cepa L.

Directory of Open Access Journals (Sweden)

Mousa IZADKHAH

2010-03-01

Full Text Available To evaluate the effect of different sowing methods on water use efficiency, relative water content and some vegetative growth parameters of onion a study was carried out in the Agriculturalr research Center of East Azarbayjan in 2007-2008 cropping season. The experiment was a factorial by using the randomized complete block design with 4 treaments and 4 replications. The first factor was consistting of two sowing methods, dirct sowing (DS and the transplanting method (TM, the second factor was including two onion cultivars �Azarshahr� (red hull and later maturing and �Gooli-Ghesseh Zanjan� (bright-red, early maturing. Analysis of variance for the measured traits indicated that except for the relative water content (RWC, other traits were significant influenced by the sowing methods. TM had higher values of water use efficiency (WUE, bulbing ratio (BR, aerial leaves length (ALL, leaf area (LA, leaf area index (LAI, leaves dry weight (LDW, leaves fresh weight (LFW and leaves saturation weight (LSW than the DS methods. Maximum WUE (6.07 kg m3 and minimum WU (9381 m3 ha-1 were obtained in TM. However, the lowest WUE (4.19 kg m3 and the highest WU (115921 m3 ha-1 was obtained with DS. In other words, in TM water economizing was 1.5 tim, amount of yield was increased up 15% (in comparison with DS. Also among the cultivars except for the RWC, WUE and BR other traits were significantly. The sowing method x cultivar interaction were not significant. For the studied traits, TM and red �Azarshahr� cv. were better than the DS and �Gooli-Ghesseh Zanjan�, thus thy were identified the best treatments for experiment therefore it is recommended for the places with the same environmental conditions of this experiment.

Evaluating algal growth performance and water use efficiency of pilot-scale revolving algal biofilm (RAB) culture systems.

Science.gov (United States)

Gross, Martin; Mascarenhas, Vernon; Wen, Zhiyou

2015-10-01

A Revolving Algal Biofilm (RAB) growth system in which algal cells are attached to a flexible material rotating between liquid and gas phases has been developed. In this work, different configurations of RAB systems were developed at pilot-scale by retrofitting the attachment materials to a raceway pond (2000-L with 8.5 m(2) footprint area) and a trough reservoir (150 L with 3.5 m(2) footprint area). The algal growth performance and chemical composition, as well as the water evaporative loss and specific water consumption were evaluated over a period of nine months in a greenhouse environment near Boone, Iowa USA. Additionally a raceway pond was run in parallel, which served as a control. On average the raceway-based RAB and the trough-based RAB outperformed the control pond by 309% and 697%, respectively. A maximum productivity of 46.8 g m(-2) day(-1) was achieved on the trough-based RAB system. The evaporative water loss of the RAB system was modeled based on an energy balance analysis and was experimentally validated. While the RAB system, particularly the trough-based RAB, had higher water evaporative loss, the specific water consumption per unit of biomass produced was only 26% (raceway-based RAB) and 7% (trough-based RAB) of that of the control pond. Collectively, this research shows that the RAB system is an efficient algal culture system and has great potential to commercially produce microalgae with high productivity and efficient water use. © 2015 Wiley Periodicals, Inc.

Energy Efficiency, Water Efficiency, and Renewable Energy Site Assessment: San Juan National Forest - Dolores Ranger District, Colorado

Energy Technology Data Exchange (ETDEWEB)

Kandt, Alicen J. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Kiatreungwattana, Kosol [National Renewable Energy Lab. (NREL), Golden, CO (United States)

2018-01-26

This report summarizes the results from an energy efficiency, water efficiency, and renewable energy site assessment of the Dolores Ranger District in the San Juan National Forest in Colorado. A team led by the U.S. Department of Energy's National Renewable Energy Laboratory (NREL) conducted the assessment with United States Forest Service (USFS) personnel on August 16-17, 2016, as part of ongoing efforts by USFS to reduce energy and water use and implement renewable energy technologies. The assessment is approximately an American Society of Heating, Refrigerating, and Air-Conditioning Engineers Level 2 audit and meets Energy Independence and Security Act requirements.

Reduced nighttime transpiration is a relevant breeding target for high water-use efficiency in grapevine.

Science.gov (United States)

Coupel-Ledru, Aude; Lebon, Eric; Christophe, Angélique; Gallo, Agustina; Gago, Pilar; Pantin, Florent; Doligez, Agnès; Simonneau, Thierry

2016-08-09

Increasing water scarcity challenges crop sustainability in many regions. As a consequence, the enhancement of transpiration efficiency (TE)-that is, the biomass produced per unit of water transpired-has become crucial in breeding programs. This could be achieved by reducing plant transpiration through a better closure of the stomatal pores at the leaf surface. However, this strategy generally also lowers growth, as stomatal opening is necessary for the capture of atmospheric CO2 that feeds daytime photosynthesis. Here, we considered the reduction in transpiration rate at night (En) as a possible strategy to limit water use without altering growth. For this purpose, we carried out a genetic analysis for En and TE in grapevine, a major crop in drought-prone areas. Using recently developed phenotyping facilities, potted plants of a cross between Syrah and Grenache cultivars were screened for 2 y under well-watered and moderate soil water deficit scenarios. High genetic variability was found for En under both scenarios and was primarily associated with residual diffusion through the stomata. Five quantitative trait loci (QTLs) were detected that underlay genetic variability in En Interestingly, four of them colocalized with QTLs for TE. Moreover, genotypes with favorable alleles on these common QTLs exhibited reduced En without altered growth. These results demonstrate the interest of breeding grapevine for lower water loss at night and pave the way to breeding other crops with this underexploited trait for higher TE.

A run-around heat exchanger system to improve the energy efficiency of a home appliance using hot water

International Nuclear Information System (INIS)

Park, Jae Sung; Jacobi, Anthony M.

2009-01-01

A significant portion of the energy consumed by many home appliances using hot water is used to heat cold supply water. Such home appliances generally are supplied water at a temperature lower than the ambient temperature, and the supply water is normally heated to its maximum operating temperature, often using natural gas or an electrical heater. In some cases, it is possible to pre-heat the supply water and save energy that would normally be consumed by the natural gas or electrical heater. In order to save the energy consumed by an appliance using water heater, a run-around heat exchanger system is used to transfer heat from the ambient to the water before an electrical heater is energized. A simple model to predict the performance of this system is developed and validated, and the model is used to explore design and operating issues relevant to the run-around heat exchanger system. Despite the additional power consumption by the fan and pump of the run-around heat exchanger system, the experimental data and analysis show that for some systems the overall energy efficiency of the appliance can be improved, saving about 6% of the energy used by the baseline machine.

Eutrophic water purification efficiency using a combination of hydrodynamic cavitation and ozonation on a pilot scale.

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Li, Wei-Xin; Tang, Chuan-Dong; Wu, Zhi-Lin; Wang, Wei-Min; Zhang, Yu-Feng; Zhao, Yi; Cravotto, Giancarlo

2015-04-01

This paper presents the purification of eutrophic water using a combination of hydrodynamic cavitation (HC) and ozonation (O3) at a continuous flow of 0.8 m(3) h(-1) on a pilot scale. The maximum removal rate of chlorophyll a using O3 alone and the HC/O3 combination was 62.3 and 78.8%, respectively, under optimal conditions, where the ozone utilization efficiency was 64.5 and 94.8% and total energy consumption was 8.89 and 8.25 kWh m(-3), respectively. Thus, the removal rate of chlorophyll a and the ozone utilization efficiency were improved by 26.5% and 46.9%, respectively, by using the combined technique. Meanwhile, total energy consumption was reduced by 7.2%. Turbidity linearly decreased with chlorophyll a removal rate, but no linear relationship exists between the removal of COD or UV254 and chlorophyll a. As expected, the suction-cavitation-assisted O3 exhibited higher energy efficiency than the extrusion-cavitation-assisted O3 and O3 alone methods.

Efficient Desalination of Brackish Ground Water via a Novel Capacitive Deionization Cell Using Nanoporous Activated Carbon Cloth Electrodes

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K. Laxman

2015-12-01

Full Text Available Sea water intrusion in ground water sources has made brackish water desalination a necessity in Oman. The application of capacitive deionization (CDI for the deionization of ground water samples from wells in Al-Musanaah Wilayat is proposed and demonstrated. A CDI cell is fabricated using nanoporous activated carbon cloth (ACC as the electrodes and is shown to be power efficient for desalting ground water samples with total dissolved solids (TDS of up to 4,000 mg/l. The CDI cell was able to remove up to 73% of the ionic scaling and fouling contaminants from brackish water samples. The power consumption for deionization of brackish water was estimated to be 1 kWh/m3 of desalinated water, which is much lower than the power required to process water with equivalent TDS by the reverse osmosis processes. The CDI process is elaborated, and observations and analysis of the ion adsorption characteristics and electrical properties of the capacitive cell are elucidated.

Efficient infiltration of water in the subsurface by using point-wells: A field study

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Lopik, J. V.; Schotting, R.; Raoof, A.

2017-12-01

The ability to infiltrate large volumes of water in the subsurface would have great value for battling flooding in urban regions. Moreover, efficient water infiltration is key to optimize underground aquifer storage and recovery (ASR), aquifer thermal energy storage (ATES), as well as construction dewatering systems. Usually, variable infiltration rates of large water quantities could have a huge hydrogeological impact in the upper part of (phreatic) aquifer systems. In urban regions, minimizing excessive groundwater table fluctuations are necessary. A newly developed method, Fast, High Volume Infiltration (FHVI), by Dutch dewatering companies can be used to enable fast injection into the shallow subsurface. Conventional infiltration methods are using injection wells that screen large parts of the aquifer depth, whereas FHVI uses a specific infiltration point (1-m well screen) in the aquifer. These infiltration points are generally thin, high permeable layers in the aquifer of approximately 0.5-2 meter thick, and are embedded by less permeable layers. Currently, much higher infiltration pressures in shallow aquifers can be achieved with FHVI (up to 1 bar) compared to conventional infiltration methods ( 0.2 bar). Despite the high infiltration pressures and high discharge rate near the FHVI-filter, the stresses on shallow groundwater levels are significantly reduced with FHVI. In order to investigate the mechanisms that enable FHVI, a field experiment is conducted in a sandy aquifer to obtain insight in the 3-D hydraulic pressure distribution and flow patterns around a FHVI-filter during infiltration. A detailed characterization of the soil profile is obtained by using soil samples and cone pressure tests with a specific hydraulic profiling tool to track the vertical variation in aquifer permeability. A tracer test with bromide and heat is conducted to investigate preferential flow paths. The experimental data show that tracking small heterogeneities in aquifers and

Protein-functionalized magnetic iron oxide nanoparticles: time efficient potential-water treatment

International Nuclear Information System (INIS)

Okoli, Chuka; Boutonnet, Magali; Järås, Sven; Rajarao-Kuttuva, Gunaratna

2012-01-01

Recent advances in nanoscience suggest that the existing issues involving water quality could be resolved or greatly improved using nanomaterials, especially magnetic iron oxide nanoparticles. Magnetic nanoparticles have been synthesized for the development and use, in association with natural coagulant protein for water treatment. The nanoparticles size, morphology, structure, and magnetic properties were characterized by transmission electron microscope, X-ray diffraction, and superconducting quantum interference device magnetometry. Purified Moringa oleifera protein was attached onto microemulsions-prepared magnetic iron oxide nanoparticles (ME-MION) to form stable protein-functionalized magnetic nanoparticles (PMO+ME-MION). The turbidity removal efficiency in both synthetic and surface water samples were investigated and compared with the commonly used synthetic coagulant (alum) as well as PMO. More than 90 % turbidity could be removed from the surface waters within 12 min by magnetic separation of PMO+ME-MION; whereas gravimetrically, 70 % removal in high and low turbid waters can be achieved within 60 min. In contrast, alum requires 180 min to reduce the turbidity of low turbid water sample. These data support the advantage of separation with external magnetic field (magnetophoresis) over gravitational force. Time kinetics studies show a significant enhancement in ME-MION efficiency after binding with PMO implying the availability of large surface of the ME-MION. The coagulated particles (impurities) can be removed from PMO+ME-MION by washing with mild detergent or cleaning solution. To our knowledge, this is the first report on surface water turbidity removal using protein-functionalized magnetic nanoparticle.

Protein-functionalized magnetic iron oxide nanoparticles: time efficient potential-water treatment

Energy Technology Data Exchange (ETDEWEB)

Okoli, Chuka [Royal Institute of Technology (KTH), Environmental Microbiology (Sweden); Boutonnet, Magali; Jaeras, Sven [Royal Institute of Technology (KTH), Chemical Technology (Sweden); Rajarao-Kuttuva, Gunaratna, E-mail: gkr@kth.se [Royal Institute of Technology (KTH), Environmental Microbiology (Sweden)

2012-10-15

Recent advances in nanoscience suggest that the existing issues involving water quality could be resolved or greatly improved using nanomaterials, especially magnetic iron oxide nanoparticles. Magnetic nanoparticles have been synthesized for the development and use, in association with natural coagulant protein for water treatment. The nanoparticles size, morphology, structure, and magnetic properties were characterized by transmission electron microscope, X-ray diffraction, and superconducting quantum interference device magnetometry. Purified Moringa oleifera protein was attached onto microemulsions-prepared magnetic iron oxide nanoparticles (ME-MION) to form stable protein-functionalized magnetic nanoparticles (PMO+ME-MION). The turbidity removal efficiency in both synthetic and surface water samples were investigated and compared with the commonly used synthetic coagulant (alum) as well as PMO. More than 90 % turbidity could be removed from the surface waters within 12 min by magnetic separation of PMO+ME-MION; whereas gravimetrically, 70 % removal in high and low turbid waters can be achieved within 60 min. In contrast, alum requires 180 min to reduce the turbidity of low turbid water sample. These data support the advantage of separation with external magnetic field (magnetophoresis) over gravitational force. Time kinetics studies show a significant enhancement in ME-MION efficiency after binding with PMO implying the availability of large surface of the ME-MION. The coagulated particles (impurities) can be removed from PMO+ME-MION by washing with mild detergent or cleaning solution. To our knowledge, this is the first report on surface water turbidity removal using protein-functionalized magnetic nanoparticle.

Protein-functionalized magnetic iron oxide nanoparticles: time efficient potential-water treatment

Science.gov (United States)

Okoli, Chuka; Boutonnet, Magali; Järås, Sven; Rajarao-Kuttuva, Gunaratna

2012-10-01

Recent advances in nanoscience suggest that the existing issues involving water quality could be resolved or greatly improved using nanomaterials, especially magnetic iron oxide nanoparticles. Magnetic nanoparticles have been synthesized for the development and use, in association with natural coagulant protein for water treatment. The nanoparticles size, morphology, structure, and magnetic properties were characterized by transmission electron microscope, X-ray diffraction, and superconducting quantum interference device magnetometry. Purified Moringa oleifera protein was attached onto microemulsions-prepared magnetic iron oxide nanoparticles (ME-MION) to form stable protein-functionalized magnetic nanoparticles (PMO+ME-MION). The turbidity removal efficiency in both synthetic and surface water samples were investigated and compared with the commonly used synthetic coagulant (alum) as well as PMO. More than 90 % turbidity could be removed from the surface waters within 12 min by magnetic separation of PMO+ME-MION; whereas gravimetrically, 70 % removal in high and low turbid waters can be achieved within 60 min. In contrast, alum requires 180 min to reduce the turbidity of low turbid water sample. These data support the advantage of separation with external magnetic field (magnetophoresis) over gravitational force. Time kinetics studies show a significant enhancement in ME-MION efficiency after binding with PMO implying the availability of large surface of the ME-MION. The coagulated particles (impurities) can be removed from PMO+ME-MION by washing with mild detergent or cleaning solution. To our knowledge, this is the first report on surface water turbidity removal using protein-functionalized magnetic nanoparticle.

Effects of different on-farm management on yield and water use efficiency of Potato crop cultivated in semiarid environments under subsurface drip irrigation

Science.gov (United States)

Ghazouani, Hiba; Provenzano, Giuseppe; Rallo, Giovanni; Mguidiche, Amel; Douh, Boutheina; Boujelben, Abdelhamid

2016-04-01

In Tunisia the amount of water for irrigated agriculture is higher than about 80% of the total resource.The increasing population and the rising food demand, associated to the negative effects of climate change,make it crucial to adopt strategies aiming to improve water use efficiency (WUE). Moreover, the absence of an effective public policy for water management amplifies the imbalance between water supply and its demand. Despite improved irrigation technologies can enhance the efficiency of water distribution systems, to achieve environmental goals it is also necessaryto identify on-farm management strategies accounting for actual crop water requirement. The main objective of the paper was to assess the effects of different on-farm managementstrategies (irrigation scheduling and planting date) on yield and water use efficiency of Potato crop (Solanumtuberosum L.) irrigated with a subsurface drip system, under the semi-arid climate of central Tunisia. Experiments were carried out during three growing seasons (2012, 2014 and 2015) at the High Agronomic Institute of ChottMariem in Sousse, by considering different planting dates and irrigation depths, the latter scheduled according to the climate observed during the season. All the considered treatments received the same pesticide and fertilizer management. Experiments evidenced that the climatic variability characterizing the examined seasons (photoperiod, solar radiation and average temperature) affects considerably the crop phenological stages, and the late sowing shortens the crop cycle.It has also been demonstrated that Leaf Area Index (LAI) and crop yield resulted relatively higher for those treatments receiving larger amounts of seasonal water. Crop yield varied between 16.3 t/ha and 39.1 t/ha, with a trend linearly related to the ratio between the seasonal amount of water supplied (Irrigation, I and Precipitation, P) and the maximum crop evapotranspiration (ETm). The maximum crop yield was in particular

The efficiency of a membrane bioreactor in drinking water denitrification

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Petrovič Aleksandra

2015-01-01

Full Text Available The membrane bioreactor (MBR system was investigated regarding its nitrate removal capacity from drinking water. The performance of a pilot-scale MBR was tested, depending on the operational parameters, using sucrose as a carbon source. Drinking water from the source was introduced into the reactor in order to study the influence of flow-rate on the nitrate removal and denitrification efficiency of drinking water. The content of the nitrate was around 70 mg/L and the C/N ratio was 3:1. Nitrate removal efficiencies above 90% were obtained by flow-rates lower than 4.8 L/h. The specific denitrification rates varied between 0.02 and 0.16 g/L NO3/ (g/L MLSS•d. The efficiencies and nitrate removal were noticeably affected by the flow-rate and hydraulic retention times. At the maximum flow-rate of 10.2 L/h still 68% of the nitrate had been removed, whilst the highest specific denitrification rate was achieved at 0.2738 g/L NO3/ (g/L MLSS•d. The maximum reactor removal capacity was calculated at 8.75 g NO3/m3•h.

Energy efficiency in a water supply system: Energy consumption and CO2 emission

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Helena M. Ramos

2010-09-01

Full Text Available This paper presents important fundamentals associated with water and energy efficiency and highlights the importance of using renewable energy sources. A model of multi-criteria optimization for energy efficiency based on water and environmental management policies, including the preservation of water resources and the control of water pressure and energy consumption through a hybrid energy solution, was developed and applied to a water supply system. The methodology developed includes three solutions: (1 the use of a water turbine in pipe systems where pressures are higher than necessary and pressure-reducing valves are installed, (2 the optimization of pumping operation according to the electricity tariff and water demand, and (3 the use of other renewable energy sources, including a wind turbine, to supply energy to the pumping station, with the remaining energy being sold to the national electric grid. The use of an integrated solution (water and energy proves to be a valuable input for creating benefits from available hydro energy in the water supply system in order to produce clean power, and the use of a wind source allows for the reduction of energy consumption in pumping stations, as well as of the CO2 emission to the atmosphere.

RESPONSE OF CHILE PEPPER (Capsicum annuum L. TO SALT STRESS AND ORGANIC AND INORGANIC NITROGEN SOURCES: II. NITROGEN AND WATER USE EFFICIENCIES, AND SALT TOLERANCE

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Marco Antonio Huez Lopez

2011-07-01

Full Text Available The response to two nitrogen sources on water and nitrogen use efficiencies, and tolerance of salt-stressed chile pepper plants (Capsicum annuum L. cv. Sandia was investigated in a greenhouse experiment. Low, moderate and high (1.5, 4.5, and 6.5 dS m-1 salinity levels, and two rates of organic-N fertilizer (120 and 200 kg ha-1 and 120 kg ha-1 of inorganic fertilizer as ammonium nitrate were arranged in randomized complete block designs replicated four times. The liquid organic-N source was an organic, extracted with water from grass clippings. Water use decreased about 19 and 30% in moderate and high salt-stressed plants. Water use efficiency decreased only in high salt-stressed plants. Nitrogen use efficiency decreased either by increased salinity or increased N rates. An apparent increase in salt tolerance was noted when plants were fertilized with organic-N source compared to that of inorganic-N source.

Quantitative assessments of water-use efficiency in Temperate Eurasian Steppe along an aridity gradient.

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Yizhao Chen

Full Text Available Water-use efficiency (WUE, defined as the ratio of net primary productivity (NPP to evapotranspiration (ET, is an important indicator to represent the trade-off pattern between vegetation productivity and water consumption. Its dynamics under climate change are important to ecohydrology and ecosystem management, especially in the drylands. In this study, we modified and used a late version of Boreal Ecosystem Productivity Simulator (BEPS, to quantify the WUE in the typical dryland ecosystems, Temperate Eurasian Steppe (TES. The Aridity Index (AI was used to specify the terrestrial water availability condition. The regional results showed that during the period of 1999-2008, the WUE has a clear decreasing trend in the spatial distribution from arid to humid areas. The highest annual average WUE was in dry and semi-humid sub-region (DSH with 0.88 gC mm-1 and the lowest was in arid sub-region (AR with 0.22 gC mm-1. A two-stage pattern of WUE was found in TES. That is, WUE would enhance with lower aridity stress, but decline under the humid environment. Over 65% of the region exhibited increasing WUE. This enhancement, however, could not indicate that the grasslands were getting better because the NPP even slightly decreased. It was mainly attributed to the reduction of ET over 70% of the region, which is closely related to the rainfall decrease. The results also suggested a similar negative spatial correlation between the WUE and the mean annual precipitation (MAP at the driest and the most humid ends. This regional pattern reflected the different roles of water in regulating the terrestrial ecosystems under different aridity levels. This study could facilitate the understanding of the interactions between terrestrial carbon and water cycles, and thus contribute to a sustainable management of nature resources in the dryland ecosystems.

Quantitative assessments of water-use efficiency in Temperate Eurasian Steppe along an aridity gradient.

Science.gov (United States)

Chen, Yizhao; Li, Jianlong; Ju, Weimin; Ruan, Honghua; Qin, Zhihao; Huang, Yiye; Jeelani, Nasreen; Padarian, José; Propastin, Pavel

2017-01-01

Water-use efficiency (WUE), defined as the ratio of net primary productivity (NPP) to evapotranspiration (ET), is an important indicator to represent the trade-off pattern between vegetation productivity and water consumption. Its dynamics under climate change are important to ecohydrology and ecosystem management, especially in the drylands. In this study, we modified and used a late version of Boreal Ecosystem Productivity Simulator (BEPS), to quantify the WUE in the typical dryland ecosystems, Temperate Eurasian Steppe (TES). The Aridity Index (AI) was used to specify the terrestrial water availability condition. The regional results showed that during the period of 1999-2008, the WUE has a clear decreasing trend in the spatial distribution from arid to humid areas. The highest annual average WUE was in dry and semi-humid sub-region (DSH) with 0.88 gC mm-1 and the lowest was in arid sub-region (AR) with 0.22 gC mm-1. A two-stage pattern of WUE was found in TES. That is, WUE would enhance with lower aridity stress, but decline under the humid environment. Over 65% of the region exhibited increasing WUE. This enhancement, however, could not indicate that the grasslands were getting better because the NPP even slightly decreased. It was mainly attributed to the reduction of ET over 70% of the region, which is closely related to the rainfall decrease. The results also suggested a similar negative spatial correlation between the WUE and the mean annual precipitation (MAP) at the driest and the most humid ends. This regional pattern reflected the different roles of water in regulating the terrestrial ecosystems under different aridity levels. This study could facilitate the understanding of the interactions between terrestrial carbon and water cycles, and thus contribute to a sustainable management of nature resources in the dryland ecosystems.

Effect of Leaf Water Potential on Internal Humidity and CO2 Dissolution: Reverse Transpiration and Improved Water Use Efficiency under Negative Pressure.

Science.gov (United States)

Vesala, Timo; Sevanto, Sanna; Grönholm, Tiia; Salmon, Yann; Nikinmaa, Eero; Hari, Pertti; Hölttä, Teemu

2017-01-01

The pull of water from the soil to the leaves causes water in the transpiration stream to be under negative pressure decreasing the water potential below zero. The osmotic concentration also contributes to the decrease in leaf water potential but with much lesser extent. Thus, the surface tension force is approximately balanced by a force induced by negative water potential resulting in concavely curved water-air interfaces in leaves. The lowered water potential causes a reduction in the equilibrium water vapor pressure in internal (sub-stomatal/intercellular) cavities in relation to that over water with the potential of zero, i.e., over the flat surface. The curved surface causes a reduction also in the equilibrium vapor pressure of dissolved CO 2 , thus enhancing its physical solubility to water. Although the water vapor reduction is acknowledged by plant physiologists its consequences for water vapor exchange at low water potential values have received very little attention. Consequences of the enhanced CO 2 solubility to a leaf water-carbon budget have not been considered at all before this study. We use theoretical calculations and modeling to show how the reduction in the vapor pressures affects transpiration and carbon assimilation rates. Our results indicate that the reduction in vapor pressures of water and CO 2 could enhance plant water use efficiency up to about 10% at a leaf water potential of -2 MPa, and much more when water potential decreases further. The low water potential allows for a direct stomatal water vapor uptake from the ambient air even at sub-100% relative humidity values. This alone could explain the observed rates of foliar water uptake by e.g., the coastal redwood in the fog belt region of coastal California provided the stomata are sufficiently open. The omission of the reduction in the water vapor pressure causes a bias in the estimates of the stomatal conductance and leaf internal CO 2 concentration based on leaf gas exchange

On the global relationships between photosynthetic water-use efficiency, leaf mass per unit area and atmospheric demand in woody and herbaceous plants

Science.gov (United States)

Letts, M. G.; Fox, T. A.; Gulias, J.; Galmes, J.; Hikosaka, K.; Wright, I.; Flexas, J.; Awada, T.; Rodriguez-Calcerrada, J.; Tobita, H.

2013-12-01

A global dataset was compiled including woody and herbaceous C3 species from forest, Mediterranean and grassland-shrubland ecosystems, to elucidate the dependency of photosynthetic water-use efficiency on vapour pressure deficit (D) and leaf traits. Mean leaf mass per unit area (LMA) was lower and mass-based leaf nitrogen content (Nmass) was higher in herbaceous species. Higher mean stomatal conductance (gs), transpiration rate (E) and net CO2 assimilation rate under light saturating conditions (Amax) were observed in herbs, but photosynthetic and intrinsic water-use efficiencies (WUE = Amax/E and WUEi = Amax/gs) were lower than in woody plants. Woody species maintained stricter stomatal regulation of water loss at low D, resulting in a steeper positive and linear relationship between log D and log E. Herbaceous species possessed very high gs at low D, resulting in higher ratio of substomatal to atmospheric CO2 concentrations (ci/ca) and E, but lower WUE and WUEi than woody plants, despite higher Amax. The lower WUE and higher rates of gas exchange were most pronounced in herbs with low LMA and high Nmass. Photosynthetic water use also differed between species from grassland-shrubland and Mediterranean or forest environments. Water-use efficiency showed no relationship with either D or LMA in grassland-shrubland species, but showed a negative relationship with D in forest and chaparral. The distinct photosynthetic water-use of woody and herbaceous plants is consistent with the opportunistic growth strategy of herbs and the more conservative growth strategy of woody species. Further research is recommended to examine the implications of these functional group and ecosystem differences in the contexts of climate and atmospheric change.

Towards highly efficient water photoelectrolysis

Science.gov (United States)

Elavambedu Prakasam, Haripriya

The motivation for this work was to develop an efficient and relatively inexpensive material architecture suitable for solar water splitting by photoelectrolysis. Iron (III) Oxide (hematite), has bandgap energy (˜ 2.2 eV) well suited for capturing solar spectrum, is abundant and non-toxic. However, it suffers from recombination losses due to low electron mobility and a minority carrier diffusion length of only 2--4 nm. The primary focus of this dissertation was to synthesize thin walled, self-aligned, vertically oriented nanotubular/nanoporous iron (III) oxide structures through electrochemical oxidation. The underlying hypothesis was that thin walled nanotubes would allow charge separation prior to recombination, resulting in a significant increase in the photoelectrochemical properties. Both aqueous and non-aqueous electrolytes were explored as an electrochemical oxidation solvent. Iron oxide film topologies achieved include nanopillar, nanoporous and nanoplatelet structures from aqueous electrolytes, and nanoporous and nanochannel architectures from non-aqueous electrolytes. This dissertation encompasses the first report on synthesis of nanoporous/nanochannel iron (III) oxide structures through potentiostatic anodization, as well as the use of ethylene glycol for the electrochemical oxidation of both iron and titanium. Through control of anodization parameters, including potential and anodization bath composition, excellent control over the morphology and dimensions of the synthesized iron (III) nanostructures have been achieved. As dependent upon the applied potential and electrolytic composition, diameters of the self-aligned nanopores range from 30 nm to 250 nm. The synthesized structures were crystallized in nitrogen ambient to form hematite photoanodes; a maximum photocurrent efficiency of 0.73% was obtained from nanoporous iron (III) oxide synthesized using a glycerol anodization bath. The electrochemical oxidation of titanium in fluoride ion containing

Changes in plant water use efficiency over the recent past reconstructed using palaeo plant records from the boreal forest

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Gagen, M.; Finsinger, W.; McCarroll, D.; Wagner, F.

2009-04-01

The Boreal forests contains 33% of the earth's forest cover and are located at the latitude where most of the estimated global warming is predicted to occur. Warming as a consequence of rising carbon dioxide will affect evapotranspiration within the biome, with significant consequences given that water vapour is an important greenhouse gas. However, there is also a physiological forcing associated with the effects of rising carbon dioxide on plants. Higher atmospheric carbon dioxide will reduce evapotraspiration because tree stomata tend to close under elevated carbon dioxide. The warming associated with reduced evapotranspiration is known as carbon dioxide physiological forcing and it is not well constrained. Here we suggest that future predictions of evapotranspiration flux within the Boreal forest zone might be more accurately gauged by taking account of palaeo evidence of changing plant water use efficiency and stomatal density in the two most important Boreal plant species: Pinus sylvestris and Betula nana. Stable carbon isotope ratios in tree ring cellulose and stomatal density measurements, from preserved leaves falling on the forest floor, hold a record of the plant physiological changes associated with adjustment to rising carbon dioxide. We present evidence that, rather than plants simply closing their stomatal apertures under recent elevated carbon dioxide, over the last 150 years reduced evapotranspiration in the northern Boreal forest has been associated with a powerful plastic response including reductions in stomatal conductance via changes in stomatal density and pore length. Furthermore we present evidence that trees may be reaching the limits of their ability to respond plastically to rising carbon dioxide by increasing their water use efficiency.

Water consumption characteristics and water use efficiency of winter wheat under long-term nitrogen fertilization regimes in northwest China.

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Yangquanwei Zhong

Full Text Available Water shortage and nitrogen (N deficiency are the key factors limiting agricultural production in arid and semi-arid regions, and increasing agricultural productivity under rain-fed conditions often requires N management strategies. A field experiment on winter wheat (Triticum aestivum L. was begun in 2004 to investigate effects of long-term N fertilization in the traditional pattern used for wheat in China. Using data collected over three consecutive years, commencing five years after the experiment began, the effects of N fertilization on wheat yield, evapotranspiration (ET and water use efficiency (WUE, i.e. the ratio of grain yield to total ET in the crop growing season were examined. In 2010, 2011 and 2012, N increased the yield of wheat cultivar Zhengmai No. 9023 by up to 61.1, 117.9 and 34.7%, respectively, and correspondingly in cultivar Changhan No. 58 by 58.4, 100.8 and 51.7%. N-applied treatments increased water consumption in different layers of 0-200 cm of soil and thus ET was significantly higher in N-applied than in non-N treatments. WUE was in the range of 1.0-2.09 kg/m3 for 2010, 2011 and 2012. N fertilization significantly increased WUE in 2010 and 2011, but not in 2012. The results indicated the following: (1 in this dryland farming system, increased N fertilization could raise wheat yield, and the drought-tolerant Changhan No. 58 showed a yield advantage in drought environments with high N fertilizer rates; (2 N application affected water consumption in different soil layers, and promoted wheat absorbing deeper soil water and so increased utilization of soil water; and (3 comprehensive consideration of yield and WUE of wheat indicated that the N rate of 270 kg/ha for Changhan No. 58 was better to avoid the risk of reduced production reduction due to lack of precipitation; however, under conditions of better soil moisture, the N rate of 180 kg/ha was more economic.

Evaluation of Some Morphological Characteristics, Water Use Efficiency and Essential Oil of Basil (Ocimum basilicum var. keshkeni luvelou under Application of Malva Leaves and Superabsorbent Polymer

Directory of Open Access Journals (Sweden)

S. Beigi

2016-02-01

Full Text Available Introduction: Medicinal plants are rich in active substances and primarily have been used in the manufacture of many drugs. Basil (Ocimum basilicum L. is one of the important medicinal plants whichbelongs to the Lamiaceae family. Basil essential oil content (between 0.5 to 1.5 percent varies according to climatic conditions of habitat location. Basilneeds a lot of water during growth period and it is very sensitive to water stress and shows wilting symptoms very soon after water shortage. Iran is located in an arid and semi-arid region which has little precipitation that is not enough for crop water requirements. Nowadays, the use of superabsorbent polymers is one of the ways to create sustainable agriculture and increase irrigation efficiency. They can store high water or aqueous solutions in root zone of plants and to reduce negative effects of drought stress. So, improvement of plant growth, increasing of irrigation intervals, reducing water loss and costs of irrigation is due to the application of superabsorbent polymers. Mucilages are also the herbal polysaccharides, soluble in water, and commonly include carbohydrates and can be used as hydrophilic polymers. The aims of this investigation were to study the effects of hydrophilic polymers on water use efficiency, morphological characteristics (dry matter, leaf area, and leaf number, essential oil quantity and yield of basil to harden plant to drought stress and to evaluate its potential to cultivate in arid regions. In addition, taking steps forward towards sustainable agriculture, by reducing the cost of agricultural production, helps protecting the environment. Materials and Methods: This research was conducted as a pot experiment at the department of Horticultural Science‚ college of Agricultural‚ Ferdowsi University of Mashhad‚ Iran, during 2012-2013.The research was set out in a factorial experiment on the basis of completely randomized block design with three replications

Comparative analysis of energy efficiency in water users associations

Energy Technology Data Exchange (ETDEWEB)

Abadia, R.; Rocamora, M. C.; Corcoles, J. I.; Ruiz-Canales, A.; Martinez-Romero, A.; Moreno, M. A.

2010-07-01

The government of Spain has developed an energy strategy that includes a campaign of energy audits in water users associations (WUAs) in order to improve energy efficiency in irrigation. A guideline for energy audits has been developed, standardizing the audit process in WUAs. This guideline has been implemented in 22 WUAs in the Castilla-La Mancha, Valencia, and Murcia Regions. In this paper, an analysis of the indicators proposed in the guideline is performed, and the indicators that most represent energy efficiency of WUAs are identified. Also, the suitability of the proposed indicators and classifications under different conditions are discussed. In addition, a cluster analysis is performed on WUAs to classify them according to their energetic aspects. Results show that indicators global energy efficiency (GEE) and active energy consumed per hectare (EacSr) are not adequate for analysing the evolution of energy consumption in a WUA. The most representative energy indicators are those expressing ratios between energy consumption and water volume supplied to the users as the indicators active energy consumed per volume unit (EacVs) and energy cost per volume unit (CENVs). It is conclude that using the current methodology for calculate the supply energy efficiency indicator (SEE), GEE is not an adequate indicator for energy classification of WUAs, and also that the results of the energy analysis must be used to propose measures for energy conservation and energy cost reduction. (Author) 14 refs.

Effect of Drought Stress on Water Use Efficiency and Root Dry Weight of Wheat (Triticum aesativum L. and Rye (Secale cereale L. in Competition Conditions

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F Golestani Far

2017-10-01

Full Text Available Introduction Deficiency of water during the plant growth is one of the main factors which reduce the crops production around the world. Drought stress is one of the most important tensions that may occur around the low rainfall, high temperature and wind blowing environments. Plant response to this stress depends on the stage of plant growth and drought intensity. Weeds are unwanted and harmful plants with disturbance in agricultural practices which make increase the cost of crop production and reduce the crop yields. Rye (Secale cereal L. is one of the most important weeds at wheat fields in Iran (Baghestani and Atri, 2003. Low expectations, allelopathic effects and similarity of life cycle and morphology, caused increasing of rye density in winter wheat fields. Water use efficiency (WUE as an important physiological characteristic indicates the ability of plants to water stress. WUE may be affected by climatic and soil or plant factors. In plant communities, competition is one of most important physiological topics (Evans et al, 2003. At Inter-specific competition, weeds interfere to absorbing of light, water and nutrients through the adjacency with crop and so affect the growth and yield of crops. Weeds often compete with crops for soil water and reduce the accessibility of water. Competition between weeds and crops decrease the soil moisture and cause water stress which might decrease the weeds and crops growth. When the supply of water is limited, water drainage overlap areas in soil profile could be occurred relatively fast at early of in the crop life cycle. Materials and Methods In order to study the effects of drought stress on water use efficiency and root dry weight of wheat (Triticum aesativum L. and rye (Secale cereale L. in competition conditions, a pot experiment was conducted in the greenhouse of Agriculture Faculty , University of Birjand in 2012. The experiment was arranged as factorial based on completely randomized design

Batteries for Efficient Energy Extraction from a Water Salinity Difference

KAUST Repository

La Mantia, Fabio; Pasta, Mauro; Deshazer, Heather D.; Logan, Bruce E.; Cui, Yi

2011-01-01

The salinity difference between seawater and river water is a renewable source of enormous entropic energy, but extracting it efficiently as a form of useful energy remains a challenge. Here we demonstrate a device called "mixing entropy battery

Effects of spring prescribed fire on short-term, leaf-level photosynthesis and water use efficiency in longleaf pine

Science.gov (United States)

John K. Jackson; Dylan N. Dillaway; Michael C. Tyree; Mary Anne Sword Sayer

2015-01-01

Fire is a natural and important environmental disturbance influencing the structure, function, and composition of longleaf pine (Pinus palustris Mill.) ecosystems. However, recovery of young pines to leaf scorch may involve changes in leaf physiology, which could influence leaf water-use efficiency (WUE). This work is part of a larger seasonal...

Seasonal dynamics of water use efficiency of typical forest and grassland ecosystems in China

CERN Document Server

Zhu, Xianjin; Wang, Qiufeng; Hu, Zhongmin; Han, Shijie; Yan, Junhua; Wang, Yanfen; Zhao, Liang

2014-01-01

We selected four sites of ChinaFLUX representing four major ecosystem types in China-Changbaishan temperate broad-leaved Korean pine mixed forest (CBS), Dinghushan subtropical evergreen broadleaved forest (DHS), Inner Mongolia temperate steppe (NM), and Haibei alpine shrub-meadow (HBGC)-to study the seasonal dynamics of ecosystem water use efficiency (WUE = GPP/ET, where GPP is gross primary productivity and ET is evapotranspiration) and factors affecting it. Our seasonal dynamics results indicated single-peak variation of WUE in CBS, NM, and HBGC, which were affected by air temperature (Ta) and leaf area index (LAI), through their effects on the partitioning of evapotranspiration (ET) into transpiration (T) (i.e., T/ET). In DHS, WUE was higher at the beginning and the end of the year, and minimum in summer. Ta and soil water content affected the seasonal dynamics of WUE through their effects on GPP/T. Our results indicate that seasonal dynamics of WUE were different because factors affecting the seasonal dyn...

Effects of Furrow Irrigation on the Growth, Production, and Water Use Efficiency of Direct Sowing Rice

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Chunlin He

2010-01-01

Full Text Available Rice farming is the major crop production in Asia and is predicted to increase significantly in the near future in order to meet the demands for the increasing human population. Traditional irrigation methods used in rice farming often result in great water loss. New water-saving methods are urgently needed to reduce water consumption. Three field and pot experiments were conducted to evaluate the furrow irrigation (FI system to improve water use efficiency (WUE and production of direct sowing rice in southern China. Compared to the conventional irrigation (CI system (continuous flooding irrigation, for every square hectometer of rice field, the FI system reduced water use by 3130 m3, or 48.1%, and increased grain production by 13.9% for an early cultivar. For a late cultivar, the FI system reduced water use by 2655 m3, or 40.6%, and an increase of grain production by 12.1%. The improved WUE in the FI system is attributed to (1 a significant reduction of irrigation rate, seepage, evaporation, and evapotranspiration; (2 a significant reduction in the reduced materials, such as ferrous ion (Fe2+, and therefore an increase in the vitality of the root system, evident by the increases in the number of white roots by 32.62%, and decreases in the number of black roots by 20.04% and yellow roots by 12.58%; the use of the FI system may also reduce humidity of the rice field and enhance gas transport in the soil and light penetration, which led to reduced rice diseases and increased leaf vitality; and (3 increases in tiller and effective spikes by 11.53% and the weight per thousand grains by 1.0 g. These findings suggest that the shallow FI system is a promising means for rice farming in areas with increasing water shortages.

Effects of furrow irrigation on the growth, production, and water use efficiency of direct sowing rice.

Science.gov (United States)

He, Chunlin

2010-08-03

Rice farming is the major crop production in Asia and is predicted to increase significantly in the near future in order to meet the demands for the increasing human population. Traditional irrigation methods used in rice farming often result in great water loss. New water-saving methods are urgently needed to reduce water consumption. Three field and pot experiments were conducted to evaluate the furrow irrigation (FI) system to improve water use efficiency (WUE) and production of direct sowing rice in southern China. Compared to the conventional irrigation (CI) system (continuous flooding irrigation), for every square hectometer of rice field, the FI system reduced water use by 3130 m3, or 48.1%, and increased grain production by 13.9% for an early cultivar. For a late cultivar, the FI system reduced water use by 2655 m3, or 40.6%, and an increase of grain production by 12.1%. The improved WUE in the FI system is attributed to (1) a significant reduction of irrigation rate, seepage, evaporation, and evapotranspiration; (2) a significant reduction in the reduced materials, such as ferrous ion (Fe2+), and therefore an increase in the vitality of the root system, evident by the increases in the number of white roots by 32.62%, and decreases in the number of black roots by 20.04% and yellow roots by 12.58%; the use of the FI system may also reduce humidity of the rice field and enhance gas transport in the soil and light penetration, which led to reduced rice diseases and increased leaf vitality; and (3) increases in tiller and effective spikes by 11.53% and the weight per thousand grains by 1.0 g. These findings suggest that the shallow FI system is a promising means for rice farming in areas with increasing water shortages.

[Efficiency of photodecomposition of trace NDMA in water by UV irradiation].

Science.gov (United States)

Xu, Bing-Bing; Chen, Zhong-Lin; Qi, Fei; Ma, Jun

2008-07-01

Efficiency of photodecomposition of trace NDMA by UV irradiation was investigated with analyzing the initial concentration of NDMA, solution pH, irradiation area, irradiation intensity and water quality effect on NDMA photolysis. NDMA could be effectively photodegraded by UV irradiation. The removal efficiency of NDMA was 97.5% after 5 min of UV irradiation. Effect of initial NDMA concentration on photodecomposition of NDMA was not remarkable. With pH value ascending, the removal rate of NDMA photodecomposition decreased. The yields of photoquantum were more under lower solution pH than that under higher pH. NDMA had fastest reaction rate at solution pH = 2.2. Removal efficiency of NDMA increased with the available irradiation area ascending. Increscent ultraviolet irradiation intensity was good for NDMA degradation. Water quality affected the removal of NDMA slightly. The removal efficiency of NDMA in tap water and Songhua River raw water were 96.7% and 94.8%, respectively.

Quantitative Assessment of Water Use Efficiency in Urban and Domestic Buildings

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Vicente Santiago-Fandiño

2013-08-01

Full Text Available This paper discusses the potential of water savings at property, household and urban levels, through the application of environmentally sound technologies (ESTs, as well as their quantification using the software Wise Water. Household centered measures are identified that allow for significant reduction of drinking water consumption with comparatively small effort, and without limitation of comfort. Furthermore, a method for the estimation of water recycling, for rainwater harvesting and for the utilization potential as locally available renewable freshwater is presented. Based on this study, the average drinking water consumption in urban households of industrialized countries could be reduced by approximately one third, without significant investment costs, either within the framework of new constructions or by the remodeling of water and sanitation systems in residential buildings. By using a secondary water quality, the drinking water demand could even be reduced by 50%. In the case of an area-wide application, the overall fresh water demand of cities and the exploitation of fresh water resources could be significantly reduced. Due to the comparability of the domestic water use of the investigated households, the findings are internationally transferable, for example to countries in Europe, Asia, and also the USA.

Quantitative variation in water-use efficiency across water regimes and its relationship with circadian, vegetative, reproductive, and leaf gas-exchange traits.

Science.gov (United States)

Edwards, Christine E; Ewers, Brent E; McClung, C Robertson; Lou, Ping; Weinig, Cynthia

2012-05-01

Drought limits light harvesting, resulting in lower plant growth and reproduction. One trait important for plant drought response is water-use efficiency (WUE). We investigated (1) how the joint genetic architecture of WUE, reproductive characters, and vegetative traits changed across drought and well-watered conditions, (2) whether traits with distinct developmental bases (e.g. leaf gas exchange versus reproduction) differed in the environmental sensitivity of their genetic architecture, and (3) whether quantitative variation in circadian period was related to drought response in Brassica rapa. Overall, WUE increased in drought, primarily because stomatal conductance, and thus water loss, declined more than carbon fixation. Genotypes with the highest WUE in drought expressed the lowest WUE in well-watered conditions, and had the largest vegetative and floral organs in both treatments. Thus, large changes in WUE enabled some genotypes to approach vegetative and reproductive trait optima across environments. The genetic architecture differed for gas-exchange and vegetative traits across drought and well-watered conditions, but not for floral traits. Correlations between circadian and leaf gas-exchange traits were significant but did not vary across treatments, indicating that circadian period affects physiological function regardless of water availability. These results suggest that WUE is important for drought tolerance in Brassica rapa and that artificial selection for increased WUE in drought will not result in maladaptive expression of other traits that are correlated with WUE.

Enhancing Efficiency of Water Supply – Product Market Competition versus Trade

OpenAIRE

Reto Foellmi; Urs Meister

2004-01-01

This paper analyses and compares potential efficiency gains induced by the introduction of product market competition and cross boarder trade in the piped water market. We argue that due to the specific circumstances in the water sector product market competition, i.e. competition by common carriage is not expected to be very intensive. The connection of networks could alternatively be used for cross boarder trade between neighboured water utilities. We show that competition by common carriag...

Gravimetric phenotyping of whole plant transpiration responses to atmospheric vapour pressure deficit identifies genotypic variation in water use efficiency.

Science.gov (United States)

Ryan, Annette C; Dodd, Ian C; Rothwell, Shane A; Jones, Ros; Tardieu, Francois; Draye, Xavier; Davies, William J

2016-10-01

There is increasing interest in rapidly identifying genotypes with improved water use efficiency, exemplified by the development of whole plant phenotyping platforms that automatically measure plant growth and water use. Transpirational responses to atmospheric vapour pressure deficit (VPD) and whole plant water use efficiency (WUE, defined as the accumulation of above ground biomass per unit of water used) were measured in 100 maize (Zea mays L.) genotypes. Using a glasshouse based phenotyping platform with naturally varying VPD (1.5-3.8kPa), a 2-fold variation in WUE was identified in well-watered plants. Regression analysis of transpiration versus VPD under these conditions, and subsequent whole plant gas exchange at imposed VPDs (0.8-3.4kPa) showed identical responses in specific genotypes. Genotype response of transpiration versus VPD fell into two categories: 1) a linear increase in transpiration rate with VPD with low (high WUE) or high (low WUE) transpiration rate at all VPDs, 2) a non-linear response with a pronounced change point at low VPD (high WUE) or high VPD (low WUE). In the latter group, high WUE genotypes required a significantly lower VPD before transpiration was restricted, and had a significantly lower rate of transpiration in response to VPD after this point, when compared to low WUE genotypes. Change point values were significantly positively correlated with stomatal sensitivity to VPD. A change point in stomatal response to VPD may explain why some genotypes show contradictory WUE rankings according to whether they are measured under glasshouse or field conditions. Furthermore, this novel use of a high throughput phenotyping platform successfully reproduced the gas exchange responses of individuals measured in whole plant chambers, accelerating the identification of plants with high WUE. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Efficiency and productivity terms for water management: A matter of contextual relativism versus general absolutism

NARCIS (Netherlands)

Halsema, van G.E.; Vincent, L.F.

2012-01-01

Growing water scarcity and increasing demands for agricultural products generate much debate about improving the agricultural sector's water use efficiency and productivity. Agricultural engineering traditions feed this debate with notions such as agricultural yield gaps and low water use

High water-use efficiency and growth contribute to success of non-native Erodium cicutarium in a Sonoran Desert winter annual community.

Science.gov (United States)

Kimball, Sarah; Gremer, Jennifer R; Barron-Gafford, Greg A; Angert, Amy L; Huxman, Travis E; Venable, D Lawrence

2014-01-01

The success of non-native, invasive species may be due to release from natural enemies, superior competitive abilities, or both. In the Sonoran Desert, Erodium cicutarium has increased in abundance over the last 30 years. While native species in this flora exhibit a strong among-species trade-off between relative growth rate and water-use efficiency, E. cicutarium seems to have a higher relative growth rate for its water-use efficiency value relative to the pattern across native species. This novel trait combination could provide the non-native species with a competitive advantage in this water-limited environment. To test the hypothesis that E. cicutarium is able to achieve high growth rates due to release from native herbivores, we compared the effects of herbivory on E. cicutarium and its native congener, Erodium texanum. We also compared these two species across a range of environmental conditions, both in a common garden and in two distinct seasons in the field, using growth analysis, isotopic compositions and leaf-level gas exchange. Additionally, we compared the competitive abilities of the two Erodium species in a greenhouse experiment. We found no evidence of herbivory to either species. Physiological measurements in a common environment revealed that E. cicutarium was able to achieve high growth rates while simultaneously controlling leaf-level water loss. Non-native E. cicutarium responded to favourable conditions in the field with greater specific leaf area and leaf area ratio than native E. texanum. The non-native Erodium was a stronger competitor than its native congener in a greenhouse competition experiment. The ability to maintain relatively higher values of water-use efficiency:relative growth rate in comparison to the native flora may be what enables E. cictarium to outcompete native species in both wet and dry years, resulting in an increase in abundance in the highly variable Sonoran Desert.

Use of organic mulch to enhance water-use efficiency and peach production under limiting soil conditions in a three-year-old orchard

Energy Technology Data Exchange (ETDEWEB)

Lordan, J.; Pascual, M.; Villar, J.M.; Fonseca, F.; Papió, J.; Montilla, V.; Rufat, J.

2015-07-01

Mulching techniques have emerged in recent years to overcome soil constraints and improve fruit tree productivity. The object of this study was to evaluate the effects of a low-cost organic mulch application in a newly planted peach orchard under a ridge planting system. Three treatments were performed in 12 elementary plots using a randomized complete block design. The orchard was drip-irrigated. Mulch was applied in two treatments, which differed in fertigation (none vs. multi-nutrient fertigation), while the third treatment did not include either mulch or fertigation and served as the control. Treatments were compared in terms of their effects on the physical properties of the soil, crop response, and water-use efficiency. Mulch treatments did not alter the soil bulk density. However, the mulch significantly (p=0.0004) increased the water infiltration rate (2.21 mm/h vs. 121 mm/h), which is a key issue when working in high frequency irrigation systems under soil limiting conditions. Similarly, mulched treatments showed a more favorable water status both in the second and the third year, which was translated in a better crop response. Thus, mulched treatments recorded higher yields both in the second (+155%, p=0.0005) and the third year (+53%, p=0.0007) of the experiment. Water use efficiency (WUEagr) was higher in the mulch treatments (+50% in average, p=0.0007) than in the control in the third year of the study. On the basis of our results, we propose that organic-mulching techniques should be considered as a beneficial practice to apply in fruit-trees production under limiting soil conditions.(Author)

Use of organic mulch to enhance water-use efficiency and peach production under limiting soil conditions in a three-year-old orchard

Directory of Open Access Journals (Sweden)

Joan Lordan

2015-12-01

Full Text Available Mulching techniques have emerged in recent years to overcome soil constraints and improve fruit tree productivity. The object of this study was to evaluate the effects of a low-cost organic mulch application in a newly planted peach orchard under a ridge planting system. Three treatments were performed in 12 elementary plots using a randomized complete block design. The orchard was drip-irrigated. Mulch was applied in two treatments, which differed in fertigation (none vs. multi-nutrient fertigation, while the third treatment did not include either mulch or fertigation and served as the control. Treatments were compared in terms of their effects on the physical properties of the soil, crop response, and water-use efficiency. Mulch treatments did not alter the soil bulk density. However, the mulch significantly (p=0.0004 increased the water infiltration rate (2.21 mm/h vs. 121 mm/h, which is a key issue when working in high frequency irrigation systems under soil limiting conditions. Similarly, mulched treatments showed a more favorable water status both in the second and the third year, which was translated in a better crop response. Thus, mulched treatments recorded higher yields both in the second (+155%, p=0.0005 and the third year (+53%, p=0.0007 of the experiment. Water use efficiency (WUEagr was higher in the mulch treatments (+50% in average, p=0.0007 than in the control in the third year of the study. On the basis of our results, we propose that organic-mulching techniques should be considered as a beneficial practice to apply in fruit-trees production under limiting soil conditions.

Water use efficiency at basin and farm scales

Science.gov (United States)

Ehsan Goodarzi; Lotfollah Ziaei; Saeid Eslamian

2016-01-01

The available water resources in basins are becoming scarce while demands for water are considerably increasing among various sectors due to economic and population growths. Water deficiency is becoming a main constraint for sustainable regional development and it is the primary motivation in creating water to supply user requirements in particular for agricultural ...

Highly efficient 6-stroke engine cycle with water injection

Science.gov (United States)

Szybist, James P; Conklin, James C

2012-10-23

A six-stroke engine cycle having improved efficiency. Heat is recovered from the engine combustion gases by using a 6-stroke engine cycle in which combustion gases are partially vented proximate the bottom-dead-center position of the fourth stroke cycle, and water is injected proximate the top-dead-center position of the fourth stroke cycle.

The Effect of Different Levels of Irrigation and Nitrogen Fertilizer on Yield and Water Use Efficiency of Potato in Subsurface Drip Irrigation

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Mohammad Jolaini

2017-06-01

Full Text Available Introduction: After wheat, rice and corn, potato is the fourth most important food plant in the world. In comparison with other species, potato is very sensitive to water stress because of its shallow root system: approximately 85% of the root length is concentrated in the upper 0.3-0.4 m of the soil. Several studies showed that drip irrigation is an effective method for enhancing potato yield. Fabeiro et al. (2001 concluded that tuber bulking and ripening stages were found to be the most sensitive stages of water stress with drip irrigation. Water deficit occurring in these two growth stages could result in yield reductions. Wang et al. (2006 investigated the effects of drip irrigation frequency on soil wetting pattern and potato yield. The results indicated that potato roots were not limited in wetted soil volume even when the crop was irrigated at the highest frequency while high frequency irrigation enhanced potato tuber growth and water use efficiency (WUE. Though information about irrigation and N management of this crop is often conflicting in the literature, it is accepted generally that production and quality are highly influenced by both N and irrigation amounts and these requirements are related to the cropping technique. Researches revealed that nitrogen fertilizers play a special role in the growth, production and quality of potatoes. Materials and Methods: A factorial experiment in randomized complete block design with three replications was carried out during two growing seasons. Studied factors were irrigation frequency (I1:2 and I2:4 days interval and nitrogen fertilizer levels (applying 100 (N1, 75 (N2 and 50 (N3 % of the recommended amount. Nitrogen fertilizer was applied through irrigation water. In each plot two rows with within-and between-row spacing of 45 and 105 cm and 20 m length. The amount of nitrogen fertilizer for the control treatment was determined by soil analysis (N1. In all treatments, nitrogen fertilizer

Effect of magnetic field and silver nanoparticles on yield and water use efficiency of Carum copticum under water stress conditions

Directory of Open Access Journals (Sweden)

Seghatoleslami Mohammadjavad

2015-03-01

Full Text Available Normally the productivity of cropping systems in arid and semi- arid regions is very low. The sustainable agricultural systems try to find out environmental friendly technologies based on physical and biological treatments to increase crop production. In this study two irrigation treatments (control and water stress and six methods of fertilizer treatment (control, NPK-F, using magnetic band- M, using silver nano particles- N, M+N and M+N+50% F on performance of ajowan were compared. Results showed that treatments with magnetic field or base fertilizer had more yield compared to the control and silver nanoparticles (N treatments. Application of silver nanoparticles had no positive effect on yield. The highest seed and biomass WUE achieved in base fertilizer or magnetic field treatments. Under water stress treatment, seed WUE significantly increased. In conclusion magnetic field exposure, probably by encourage nutrient uptake efficiency could be applied to reduce fertilizer requirement. On the other hand the cultivation of plants under low MF could be an alternative way of WUE improving.

Field evaluation of urea fertilizer and water use efficiency by tomato under trickle fertigation and furrow irrigation in the Islamic Republic of Iran

International Nuclear Information System (INIS)

Sagheb, N.; Hobbi, M.S.

2002-01-01

Urea fertilizer and water use efficiency by tomato (Early Urbana VF) were studied in a sandy loam soil, comparing trickle fertigation and conventional furrow irrigation -- band fertilization systems. During the period of 1995-1998, a conventional treatment, NS, with band application of 50, 150 and 100 kg N as urea, P as diammonium phosphate and K as potassium sulfate respectively was carried out. The average concentration of N in the total irrigation water was 0, 38, 76 and 114 mg/L for the N0, N1, N2 and N3 fertigation treatments, respectively. All fertigation treatments also received equally 24 and 16 mg/L P and K, respectively. An increase of K for the conventional treatment to 1200 kg/ha in 1998 coincided with the increase of the same element to 190 mg/L for the trickle irrigated treatments. To evaluate the urea-N use efficiency, the plants of isotope subplots received 2% 15 N a.e. urea. The soil moisture in all treatments was measured by the neutron moisture gauge. During the first 3 years of experimentation there was no significant difference between the yields of the treatments. For the years 1995 through 1997 the average tomato yield was low in comparison to the yield shown in most reports. The yield variance among treatments and years was negligible. The highest fruit yield, 27.3 t/ha for the N1 treatment was observed in 1997. In this experiment, the low yield and urea-N use efficiency can be primarily attributed to unbalanced applied fertilizers in the trickle irrigation system. The highest urea-N use efficiency was 12.3% for the fertigation N1 treatment in 1997. In the 1998, a repetition of the experiment with increasing K rates for all treatments at the same experimental site, led to a considerable increase in yield and urea-N use efficiency as compared to previous years. The tomato fresh fruit yield attained for N0, N1, N2, N3 and NS respectively 84, 76, 69, 36 and 26 t/ha. Based on the 14N/15N ratio analysis of the dry matter the urea-N use efficiency

[Effects of plastic film mulching and rain harvesting modes on chlorophyll fluorescence characteristics, yield and water use efficiency of dryland maize].

Science.gov (United States)

Li, Shang-Zhong; Fan, Ting-Lu; Wang, Yong; Zhao, Gang; Wang, Lei; Tang, Xiao-Ming; Dang, Yi; Zhao, Hui

2014-02-01

The differences on chlorophyll fluorescence parameters, yield and water use efficiency of dryland maize were compared among full plastic film mulching on double ridges and planting in catchment furrows (FFDRF), half plastic film mulching on double ridges and planting in catchment furrows (HFDRF), plastic film mulching on ridge and planting in film-side (FS), and flat planting with no plastic film mulching (NM) under field conditions in dry highland of Loess Plateau in 2007-2012. The results showed that fluorescence yield (Fo), the maximum fluorescence yield (Fm), light-adapted fluorescence yield when PS II reaction centers were totally open (F), light-adapted fluorescence yield when PS II reaction centers closed (Fm'), the maximal photochemical efficiency of PS II (Fv/Fm), the actual photochemical efficiency of PS II in the light (Phi PS II), the relative electron transport rate (ETR), photochemical quenching (qP) and non-photochemical quenching (qN) in maize leaves of FFDRF were higher than that of control (NM), and the value of 1-qP was lower than that of control, at 13:00, chlorophyll fluorescence parameters values of FFDRF was significantly higher than control, which were increased by 5.3%, 56.8%, 10.7%, 36.3%, 23.6%, 56.7%, 64.4%, 45.5%, 23.6% and -55.6%, respectively, compared with the control. Yield and water use efficiency of FFDRF were the highest in every year no matter dry year, normal year, humid year and hail disaster year. Average yield and water use efficiency of FFDRF were 12,650 kg x hm(-2) and 40.4 kg x mm(-1) x hm(-2) during 2007-2012, increased by 57.8% and 61.6% compared with the control, respectively, and also significantly higher compared with HFDRF and PS. Therefore, it was concluded that FFDRF had significantly increased the efficiency of light energy conversion and improved the production capacity of dryland maize.