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Irrigation is an important adaptation strategy to cope with climate change which reduces vulnerability to water stress and improves crop productivity to feed millions. There is evidence of crop yield stagnation in many developing countries, and irrigation efficiency is claimed to increase crop productivity. Therefore, this paper uses data envelopment analysis to evaluate the farmer’s productivity through technical efficiency (TE), i.e., the relationship between resource inputs and outputs of 513 paddy farmers in Eastern India. The results show that the farms are, on average operating at 14% TE, leaving a considerable scope to improve up to 86% to reach the optimal level. A significant difference is observed between irrigated and rain-fed paddy farmers, such that10% of the irrigated farms achieved efficiency scores over 40% and only 2% of rain-fed farms achieved the same. The tobit and beta fit regression models are estimated to find out the factors that influence the TE. Both surface water and groundwater sources of irrigation are used as predictors, along with other socio-demographic factors. Access to surface water irrigation is identified to be a significant determinant of farm efficiency, however, surface water irrigation, such as canal irrigation, is accessible only to farmers living on plain land. Farmers living on highlands need to explore other sources of irrigation practices, such as drip and sprinkler, that can increase TE and farm productivity. Therefore, this paper calls for government intervention to provide extensive training and facilities for these micro-irrigation practices.

Irrigation is an important adaptation strategy to cope with climate change which reduces vulnerability to water stress and improves crop productivity to feed millions. There is evidence of crop yield stagnation in many developing countries, and irrigation efficiency is claimed to increase crop productivity. Therefore, this paper uses data envelopment analysis to evaluate the farmer's productivity through technical efficiency (TE), i.e., the relationship between resource inputs and outputs of 513 paddy farmers in Eastern India. The results show that the farms are, on average operating at 14% TE, leaving a considerable scope to improve up to 86% to reach the optimal level. A significant difference is observed between irrigated and rain-fed paddy farmers, such that10% of the irrigated farms achieved efficiency scores over 40% and only 2% of rain-fed farms achieved the same. The tobit and beta fit regression models are estimated to find out the factors that influence the TE. Both surface water and groundwater sources of irrigation are used as predictors, along with other socio-demographic factors. Access to surface water irrigation is identified to be a significant determinant of farm efficiency, however, surface water irrigation, such as canal irrigation, is accessible only to farmers living on plain land. Farmers living on highlands need to explore other sources of irrigation practices, such as drip and sprinkler, that can increase TE and farm productivity. Therefore, this paper calls for government intervention to provide extensive training and facilities for these micro-irrigation practices. • Data Envelopment analysis was estimated to derive the paddy efficiency among the tribal villages of eastern India. • The DEA estimates show that average Technical efficiency in the study region is much below the national average. • Irrigated farmers are more efficient than the rain-fed farmers. Surface irrigation is the dominate factor. • Rain-fed paddy cultivators' farm efficiency would improve by 6.5%, if they had irrigated. • Semi-mountainous regions with little access to surface irrigation must explore micro-irrigation practices such as drips and sprinklers. [ABSTRACT FROM AUTHOR]

Agriculture is the main consumer of freshwater in the world. The paper described the process of virtual water content and flow in crops. Differences in climatic conditions of different regions in China result in large differences in water consumption during crop growth. The virtual water trade in crops connects water flows within and between regions, linking the actual water consumption with the invisible water trade as a whole. The objective of the paper was supplying the agricultural products virtual water trade evaluation system, determining quantitatively the virtual water flow within the region & regional. Using meteorological and agricultural data from 2003 to 2010, a comprehensive analysis of China's domestic & international virtual water trade of agricultural products has been undertaken. The virtual water for the three primary crops and virtual water trade are discussed. The virtual water content of grain crops in northern & southern China was 1293 m 3 /t & 942 m 3 /t, respectively; the national average value was 1117 m 3 /t; and the regional differences in virtual water content for each crop were significant. China's inter-regional agricultural products virtual water trade was not consistent with water resource endowment expectations. The transfer of crops from northern to southern regions would have a significant impact on the sustainable utilization of water resources and would exacerbate water resources shortages in northern regions. China had a trade surplus in global virtual water trade of agricultural products. The exported agricultural products virtual water amounted to 31.5 billion m 3 /yr., and the imported amount was 145 billion m 3 /yr. The net import of virtual water embedded in agricultural products increased from 44 billion m 3 /yr. in 2003 to 178 billion m 3 /yr. in 2010. It is further concluded that the trend for agricultural products total virtual water, green water, and blue water is that China is increasing its imports year on year. A large increase in imports of agricultural products has led to a decline in the rate of self-sufficiency in domestic agricultural production. The paper provided the basis for the comprehensive evaluation of crop planting structure adjustment, grain import & export, and the potential of regional water resources development and utilization. [ABSTRACT FROM AUTHOR]

Water scarcity threatens food security and leads to various economic, social, and environmental challenges, particularly in arid and semi-arid regions. As the agricultural sector consumes the most significant amount of water, conserving water resources in this sector is particularly important. Cultivation of low-water-demand (LWD) crops with high value-added is one of the effective measures to reduce agricultural water demand and improve farmers' livelihoods. However, changing water-intensive crops to LWD crops (e.g., medicinal plants) is voluntary pro-environmental behavior. Considering the role of psychological theories in understanding and explaining human behaviors, the main purpose of the current paper is to explore the socio-psychological determinants underlying farmers' intention to adopt an LWD cropping pattern using the Health Belief Model (HBM). In this regard, data were collected using face-to-face interviews with 184 farmers living in Zanjan province, Iran to examine their intention to cultivate LWD medicinal plants. Using structural equation modeling for data analysis, the HBM explained 49% of the variance in farmers' behavioral intentions. The structural equation modeling outcomes also revealed that self-efficacy, perceived barriers, cues to action, and perceived benefits are significantly related to farmers' intention to choose medicinal plants. Overall, the findings indicated the effectiveness and applicability of the HBM in illustrating farmers' intention to change their cropping pattern. Applying some strategies such as providing the necessary facilities and training programs for farmers, as well as, advertisements aimed at promoting the cultivation of medicinal plants can significantly contribute to conserving water resources in the study area. • Evaluating farmers' intention to medicinal crops using the Health Belief Model. • The HBM accounted for 49% of the variance of the farmers' behavioral intentions. • Self-efficacy, perceived expectations, and cues to action affect farmers intentions. • Self-efficacy was identified as the main predictor of farmers behavioral intentions. • Cultivating medicinal crops help conserving water resources in the study area. [ABSTRACT FROM AUTHOR]

Climate change has led to extreme weather events and food security issues, which have become urgent global problems. Crop models and hydrological models play important roles in analyzing these issues, but crop models have limitations in large-scale simulations, and hydrological models have shortcomings in depicting underlying surface details. Jointly using the two models to complement each other's shortcomings is becoming an important method, playing an important role in improving the quantitative characterization ability of different facets of agricultural production and is crucial to improving the efficiency of water resources utilization. This paper reviews the development process of crop and hydrological models and summarizes the widely used models at present, providing reference for researchers to select crop and hydrological models; secondly, it summarizes the types, methods, and examples of joint use of models, and analyzes possible problems in model combination; finally, some suggestions are put forward for the joint use of crop and hydrological models, providing a reference for researchers to combine models. • Retrospect on the development process of crop and hydrological models. • Summarized case studies on the combination of crop and hydrological models. • Provide an overview of cases where crop and hydrological models are used in conjunction. • General considerations and suggestions for future development. [ABSTRACT FROM AUTHOR]

There was presently a lack of multidimensional investigation on the impact of virtual water flow (VWF) on regional water use and scarcity. A framework for impact analysis of VWF in consideration of blue, green and grey water differentiation, taking the crop-water relationship estimation in 31 provinces of China as case study, was established in current paper. Results showed that, VWF, which mainly from northern to eastern plain and southeast, reduced agricultural water footprints by 8.3 (blue), 322.0 (green) and 52.5 (grey) G m3. National water stress index reduced from 1.20 (severe water stress) to 0.92 (high water stress), comparing crop consumption to production perspectives. VWF alleviated the resource-based water scarcity attributed to green water stress in south of the Yangtze River, and transformed the resource-based to systematic water scarcity in Xinjiang (XJ). Clarifying the influences of VWF on blue, green and grey water is the innovation of the analytical framework proposed in current paper. • Influences of virtual water flow (VWF) on blue, green and grey water footprint scarcity were quantified. • Green and grey VWFs and their effects on water resources were more impressive than blue water. • VWF alleviated water stress and changed water scarcity type in crop production of China. • Crop production improvement and optimization are proposed to increase the benefits of VWF. [ABSTRACT FROM AUTHOR]

Water scarcity threatens food security and leads to various economic, social, and environmental challenges, particularly in arid and semi-arid regions. As the agricultural sector consumes the most significant amount of water, conserving water resources in this sector is particularly important. Cultivation of low-water-demand (LWD) crops with high value-added is one of the effective measures to reduce agricultural water demand and improve farmers' livelihoods. However, changing water-intensive crops to LWD crops (e.g., medicinal plants) is voluntary pro-environmental behavior. Considering the role of psychological theories in understanding and explaining human behaviors, the main purpose of the current paper is to explore the socio-psychological determinants underlying farmers' intention to adopt an LWD cropping pattern using the Health Belief Model (HBM). In this regard, data were collected using face-to-face interviews with 184 farmers living in Zanjan province, Iran to examine their intention to cultivate LWD medicinal plants. Using structural equation modeling for data analysis, the HBM explained 49% of the variance in farmers' behavioral intentions. The structural equation modeling outcomes also revealed that self-efficacy, perceived barriers, cues to action, and perceived benefits are significantly related to farmers' intention to choose medicinal plants. Overall, the findings indicated the effectiveness and applicability of the HBM in illustrating farmers’ intention to change their cropping pattern. Applying some strategies such as providing the necessary facilities and training programs for farmers, as well as, advertisements aimed at promoting the cultivation of medicinal plants can significantly contribute to conserving water resources in the study area.

This paper investigates the impact of erratic rainfall and related water problems on agricultural productivity. The paper also aims to shed light on the conceptual importance of understanding the incidence and impacts of rainfall shocks for choosing feasible agricultural water risk management strategies both at household and policy levels. To achieve these goals we develop a conceptual framework, use national representative data from Zambia's crop estimates survey for 2017/2018 farming season, employ fixed effects regression approach, and find that dry spells, excessive floods, incidence of water logging are all detrimental to crop productivity. The crop-based equations also reveal the differential impacts of the rainfall shocks on different crops. Since the effect of water factors including dry spells, floods and water logging on agricultural productivity is dependent on the crop types, it is important for the Zambian government as well as other countries to take this into account when planning and implementing strategies for agricultural water risk management. • Water related problems significantly undermine agriculture productivity in Zambia. • The impacts of erratic rainfall on productivity varies depending on the type of crop. • The differential impacts of rainfall shocks calls for crop specific strategies. [ABSTRACT FROM AUTHOR]

• Variations in precipitation and temperature increase have a significant impact on wheat yields in Serbia! • Water scarcity has a significant effect on wheat yield only in the plain regions! • Change in average daily water deficit, within the period 15th November – 15th May, affects the decrease in wheat yields! • Increase in the average daily water scarcity by 0.1 mm, results with up to 250 kg/ha lower yields! In Serbia irrigation is not widely utilized to reduce water scarcity in crop production. Therefore, wheat yields largely depend on weather factors. Over the past two decades, there has been recorded a significant change in weather conditions in Serbia. Such change produces concerns about Serbia's food security and exports since wheat is among the most important agricultural products. In this paper authors analyze and quantify the impact of weather factors on the achieved wheat yields, using a set of panel data on selected Serbian municipalities in fourteen years (2000–2013). The multidimensional regression was conducted as a sort of quasi-experiment, combining data on achieved yields in selected municipalities, with data on weather factors: temperature, precipitation, extraterrestrial radiation, and evapotranspiration. Utilizing the Hargreaves method of determining reference evapotranspiration, average daily water deficit was computed as a single representative indicator of weather conditions. Testing was conducted on four predefined sub-periods within the vegetation season of wheat, and the impact of average daily water deficit on wheat yields was estimated for each of these sub-periods. Results show a robust, statistically significant impact of change in average daily water deficit on decreased wheat yields. Growth of water deficit by 0.1 mm, in the period November 15th to April 1st results with 175 kg/ha lower yields, while in the period April 1st to May 15th results in 45 kg/ha lower yields. Impact shows to be conditional on the altitude, rapidly losing on intensity and significance above 100 m. [ABSTRACT FROM AUTHOR]

Highlights • Function "yield vs. total net water" for 4 commercial cultivars of potato crop was fitted. • Irrigation strategies aiming to increase the irrigation water productivity of potato were proposed. • Crop under real farming conditions and limited volumes of irrigation water. • Optimized regulated deficit irrigation methodology increased the irrigation water productivity in the studied cultivars. Abstract This paper presents the calibration and validation processes of the MOPECO model for the simulation of 4 commercial potato cultivars (Zorba, Mirari, Monalisa and Leire), using the data from a three-year field experiment (years 2010, 2011 and 2012; two per cultivar) under deficit irrigation conditions in the Basque Country region of Spain. The optimized regulated deficit irrigation (ORDI) strategy was used in combination with the typical meteorological year (TMY) methodology to determine irrigation strategies aimed at increasing the irrigation water productivity of potato crop under real farming conditions and limited volumes of irrigation water. The growing degree-days for the whole growth cycle were 1958 °Cd, while the calibrated crop yield response (K y) values for the growth stages proposed by FAO-56 were 0.45 (vegetative period), 0.70 to 0.90 (yield formation), and 0.25 to 0.40 (ripening) depending on the consider e d cultivar. The validation results showed that MOPECO is suitable for simulating the yield versus total water (gross irrigation + effective rainfall) use under the climatic and soil conditions in this study (normalized root mean square error from 7.2 to 8.5% between observed and simulated levels). ORDI maximized the yield of the crop for different volumes of available irrigation water. The irrigation water productivity differed according to the cultivar, increasing for lower volumes of irrigation water (from 23.0 kg m−3 to 58.1 kg m−3 for Monalisa and Mirari cultivars, irrigated with 100% and 40% of the requirements, respectively). [ABSTRACT FROM AUTHOR]

Water is the most essential resource for the production of agricultural goods and services. However, high levels of water stress and increased frequency and intensity of droughts, which are mainly driven by climate change dynamics, have reduced the stock of freshwater resources in arid and semi-arid regions, such as Iran. Despite the major reduction of freshwater resources, the efficiency of irrigation water use has remained very low in the country and performance of water management schemes is far from satisfactory. Using the strengths, weaknesses, opportunities and threats/political, economic, social, technological, legal and environmental (SWOT/PESTLE) analysis, this paper explores 40 internal and external factors that influence irrigation water management in Iran and recognizes legal, social, technological and political dynamics as the major reasons for failure of irrigation water management in the country. A combination of the threats, opportunities, weaknesses and strengths (TOWS) matrix and bottleneck analysis was used to suggest irrigation water management strategies that rehabilitate the failed schemes and enhance water security in the agriculture sector. Rethinking the role of intensified agriculture in development along with raising the awareness and attitude of decision makers towards the risk of shortsighted water resource development plans, in addition to promoting agro-based industries and developing integrated plans to improve water efficiency are the strategies that can contribute to a more effective management of irrigation water in Iran. [ABSTRACT FROM AUTHOR]

Climate variability and insufficient irrigation are primary constraints to stable and higher agricultural productivity and food security in Nepal. Agriculture is the largest global freshwater user, and integration of surface- and ground-water use is frequently presented as an strategy for increasing efficiency as well as climate change adaptation. However, conjunctive management (CM) planning often ignores demand-side requirements and a broader set of sustainable development considerations, including ecosystem health and economics of different development strategies. While there is generic understanding of conjunctive use, detailed technical knowhow to realize the CM is lacking in Nepal. This article presents a holistic framework through literature reviews, stakeholders consultations and expert interviews for assessing CM and implementation prospects from a systems-level perspective. We demonstrate the framework through a case study in Western Nepal, where climatic variability and a lack of irrigation are key impediments to increased agricultural productivity and sustainable development. Results show that knowledge of water resources availability is good and that of water demand low in the Western Terai. Additional and coordinated investments are required to improve knowledge gaps as well as access to irrigation. There is therefore a need to assess water resources availability, water access, use and productivity, to fill the knowledge gaps in order to pave pathways for CM. This paper also discusses some strategies to translate prospects of conjunctive management into implementation. • Customized framework development for assessing prospects for conjunctive management. • Conjunctive management status in western Nepal assessed by applying the framework. • Knowledge on water availability and demand are moderate and low, respectively. • Additional and coordinated investments required to improve access to irrigation. [ABSTRACT FROM AUTHOR]

In this paper we present PILOTE-N, a crop model devoted to the calculation of crop production from the joint water and nitrogen soil status effects. It is the extension of PILOTE, for contexts in which water might not be the sole limiting factor for crop yield, but the same model structure and credo of parsimonious parameterisation have been kept, assuming simplified descriptions of the physical processes at play. One original aspect of PILOTE-N is the calculation of Leaf Area Index (LAI) and cumulative nitrogen plant demand from similar logistic-type functions. LAI is controlled by specific temperature sums, shape parameters and the occurrence of water and nitrogen stresses, while the time average of LAI values over critical phenological periods also affects the predicted harvest index and crop yield. As specific plant parameters are known from PILOTE, calibration was devoted to nitrogen parameters. Which governing the daily-averaged mineralization rate in a first step, then the two shape parameters of the potential nitrogen plant demand (from the dilution curve) in a second step and, at last, which allowing the link between nitrogen uptake and nitrogen of the soil. Model performance was evaluated using multiple initial soil conditions, irrigation and fertilization strategies for corn, durum wheat and sorghum, over a climatic series of 14 years, at the experimental plot of Lavalette (Montpellier, South-East of France), hence in a Mediterranean context characterized by severe, water stresses during summer, typically exceeding nitrogen stresses. Crop yield as well as the dynamics of nitrogen budget were correctly simulated (R 2  > 0.94 for grain yield, total dry matter and nitrogen in plant). The robustness of such a simple and easy-to-calibrate tool is expected to facilitate its use and implementation in other agro-pedoclimatic contexts, to decipher the effect of abiotic stresses and improve irrigation and fertilization scenarios when included in dedicated tools. [ABSTRACT FROM AUTHOR]

In many arid regions of the world, population growth, groundwater depletion, and uncertain supplies have caused water for agricultural production to become increasingly scarce. Deficit irrigation (DI) provides a potential response to water scarcity, but no consensus exists on its economic viability. In this paper, we develop an agro-economic model that connects plant growth-stage-specific evapotranspiration (ET) targets with farm profitability. We use the model to determine the economic conditions under which ET targets of less than 100% are optimal for profit-maximizing maize farmers in Colorado. With 2015 input costs, as maize grain prices increase beyond $0.19 kg −1 , DI can become optimal during the late vegetative growth stage but requires a water cost greater than U.S. $0.21 m −3 . Under some output price and water cost combinations, DI in the maturation stage also becomes optimal. These results suggest that producers could respond to increasing water scarcity with deficit irrigation, but only in a range of water costs that depends on output price and production costs. [ABSTRACT FROM AUTHOR]

In intensive breeding farms, maintaining an adequate indoor thermal environment and air quality is crucial in order to establish healthy conditions and increase productivity. In the EU, fossil fuels and electricity are the main energy sources adopted for this purpose, yet introducing renewable energy sources and efficient Heating Ventilating Air Conditioning systems would reduce energy consumption and improve sustainability. Another environmental concern in agricultural production is related to the intensive use of fertilizers, causing nitrate contamination in surface water and groundwater. Therefore, innovative strategies to reduce fertilizers and simultaneously reduce primary energy consumption are worthy of investigation. This paper addresses both issues, studying the application of geothermal heat pumps in the agro-zootechnical sector, where they are rarely applied and thus their potential needs to be verified. The study considers systems based on the closed loop configuration, i.e. Ground Source Heat Pumps (GSHP), and on the open loop configuration, i.e. Groundwater Heat Pumps (GWHP). Firstly, a pilot GSHP system for a piglet stable in Northern Italy is presented. Thanks to the use of both ground source and thermal recovery of air ventilation, the system achieves an appreciable reduction in both primary energy consumption and running costs, compared with a more traditional system typically adopted in this kind of farm. Secondly, the feasibility of an innovative concept of a GWHP combined with the irrigation system is studied through numerical modelling. The area of the piglet stable is represented in a flow and heat transport model; groundwater used by the heat pump is re-injected up-gradient during the cold season, while it is used for irrigation during the warm season. The system would provide energy-efficient climatization to the farm stables and, at the same time, promote the reuse of nitrogen in cultivated fields as a result of groundwater recirculation through irrigation. [ABSTRACT FROM AUTHOR]

Rice cultivation is globally hampered by several conditions, which urge farmers to maintain adequate production levels while properly managing irrigation water. This has noticeable repercussions on the efficient use of the resource and on water productivity. Nonetheless, more often, this latter topic is addressed by estimating the respective values, without deeply investigating the possible causes behind such discrepancies. The main objective of this paper is to overcome such limitations, by (i) providing a comprehensive and updated overview of Irrigation Water Productivity (IWP) for rice, and (ii) exploring the role of irrigation water in determining IWP value. The analysis of experimental data collected from 51 studies reveals IWP to vary between 0.09 and 8.10 kg m −3 , with mean and median values of 1.36 and 0.85 kg m −3 respectively; moreover, a non-linear relationship between irrigation water amounts and IWP (r 2 = 0.81) is depicted. Further on, data are analyzed using an econometric approach. Specifically, a multivariate linear regression model is used to shed light on the joint contribution of water inputs, regime and irrigation method to productivity. This demonstrates the significant roles of irrigation (β = −1.006) and rainfall (β = 0.062) amounts, while aerobic regime and irrigation method is proved to be a further key driver (β = −0.305). Such results enable identifying the elements to be enforced, if increasing IWP for rice is the prime objective. Finally, some implications are derived for water policy and the connections with weather-climatic and environmental conditions that are globally affecting the availability of water in agriculture. [ABSTRACT FROM AUTHOR]

Water rights trading is an effective way to promote efficient water allocation. The implementation of agricultural water rights trading can promote water saving, but may reduce the agricultural production scale in irrigation districts. Compensation for crop virtual water export can increase the benefits of agricultural water use, so as to enhance the competitiveness of economic benefit for agricultural production. This paper analyzed the relationship between agricultural water rights trading and virtual water export compensation, then a bi-level programming model was established with multiple objectives. The model was applied in Hetao irrigation district by using enumeration method. The changes of new water use of different users, benefits of irrigation district and water users with different water prices were analyzed and the optimization schemes were selected. Results show that the model through adjusting price variables including both water rights trading price and virtual water compensation price to optimize the allocation of agricultural water quantity saved among different water users, which at the same time makes both the irrigation management administration and water users get more benefit. The optimized scheme can raise the willingness of water saving in irrigation district, and enhance the competitiveness of agricultural water user against non-agricultural water user. This study provides a new method and scientific basis for the water resource management agency in their policy making. [ABSTRACT FROM AUTHOR]

Forty seven percent of the population of Pakistan is food insecure, access to food is uneven and malnutrition is widespread. In addition, food production depends greatly on irrigation, including the use of substantial volumes of water from already stressed aquifers. Our aim in this paper is to examine the implications of continued population growth on the required production of food and the implied water demand. We examine the historical trends of crop production, water use, food availability and population growth in Pakistan, and project them forward to 2050. Food availability has improved over recent decades, mostly as a result of increasing the area and water use of crops and fodder, and partly as a result of importing more pulses and cooking oils. We show that a continuation of current trends leads to nearly a doubling of the (already unsustainable) groundwater use. There is uncertainty in the magnitude of climate change impacts, but climate change may further exacerbate matters. To avoid further increases of groundwater use, some combination would be required of: more dams and other irrigation infrastructure; increasing crop yields (particularly yields per unit volume of water) at a greater rate than in the past; a change in crop mix away from high water use crops like rice and sugarcane, to crops that use less water; and, exporting less and importing more food. The alternatives appear difficult to implement quickly, so it appears likely that in the short to medium term more groundwater will be consumed, with attendant problems of water quality and sustainability. Our analysis provides new perspectives on past trends and future food and water (including groundwater) challenges. [ABSTRACT FROM AUTHOR]

Appropriate plant density is essential for crop production in rainfed areas. However, it is quite difficult to obtain the optimal plant density under plastic film mulch in different hydrological years through field experiments due to its limited treatments, and time and labor costs. Therefore, mathematical models are generally used for searching the optimal alternatives. In this paper, the Agro–Hydrological & chemical and Crop systems simulator (AHC) was adopted to model soil water dynamics, rainfed maize growth, and yield under plastic film mulch and various plant density conditions in Northeast China for different hydrological years. The results showed that the AHC model can simulate rainfed maize water use and growth under plastic film mulch and various plant density conditions, i.e., 60,000 (D1), 67,500 (D2), 75,000 (D3), 82,5000 (D4) and 90,000 plants ha−1 (D5). The average maize yields of all treatments in the severely dry (SD), moderately dry (MD), normal (N), moderately wet (MW), and severely wet (SW) years were 11440.3, 13685.4, 13821.5, 14704.8, and 14014.3 kg ha–1, respectively. Compared with non–mulch, plastic film mulch increased the maize basal crop coefficient by 0.08–0.11 and decreased the soil evaporation coefficient by 0.26–0.32, from SD and SW years, respectively. Thus, plastic film mulch augmented maize transpiration by 46.2–76.8 mm, while reduced evaporation by 163.5–186.8 mm across the simulated years. Ultimately, the maize yield under plastic film mulch was 5.9–17.4% higher than that without mulch. From D1 to D5 treatments, the decrease of soil evaporation coefficient was within 0.02 under plastic film mulch and was over 0.05 without mulch. Under plastic film mulch, the relations between plant density and net profit could be well described by the parabolic curves, and the recommended optimal plant densities of maize in the study area were 91, 101, 101, 105, and 101 thousand plants ha–1 in the SD, MS, N, MW, and SW years, respectively. Our findings provide management implications for maize cultivation in the rainfed areas of Northeast China. • The highest maize yield was observed in the moderately wet year. • Plastic film mulch increased maize optimal plant density. • Higher increase in maize yield was obtained in higher plant density with film mulch. • The highest optimal maize plant density was obtained in moderately wet year. [ABSTRACT FROM AUTHOR]

Agricultural subsurface drainage is necessary for crop production in humid, poorly drained regions with frequent rainfall. Flooding and waterlogging have become more widespread and frequent in recent years, and effective measures should be adopted to increase the subsurface drainage capacity and alleviate flooding and waterlogging disasters after short-term heavy rainfall. However, subsurface drainage focused on the layout parameters (drain depth, drain spacing, etc.) in previous studies, and these measures were limited and cumbersome in the improvement of the flow rate of subsurface drainage. Thus, we aimed to alleviate the flooding and waterlogging threats to farmland and innovatively proposed a new method to increase the flow rate of subsurface drainage, namely siphon-type subsurface drainage. The paper evaluated the performance of the siphon-type subsurface drainage by the indoor sand tank test and the HYDRUS-2D model. Three factors were considered during the experiments: conventional and improved subsurface drainage; shallow, medium, and deep drain depth; and the outlet elevation, including the outlet elevation of the drain pipe under the non-siphon drainage and the outlet elevation of the siphon pipe under the siphon drainage. The results indicated that the siphon-type subsurface drainage performed better under the conditions of steady-state ponding and ponding subsided. The flow rate of the siphon-type subsurface drainage was 27.1–45.7%, 41.8–89.8%, and 39.3–50.5% higher than that of conventional, thin-improved, and thick-improved subsurface drainage with non-siphon drainage under steady-state ponding, respectively. It also had a significant advantage when the outlet elevation was the same. The siphon-type subsurface drainage could increase the flow rate during ponding subsided and reduce the flow rate attenuation degree before the ponding disappears. The flooding removal effect of the siphon-type subsurface drainage was significantly better than that of non-siphon subsurface drainage. The water head and flow rate were used to calibrate and validate the HYDRUS-2D model. The results indicated that the simulated values of flow rate matched well with the measured ones and the relative errors were less than 10%. The influence range and absolute values of the negative water head increased with the decrease of outlet elevation, and the increase effect of flow rate increased with the decrease of the water head. The siphon-type subsurface drainage has more control distance than the non-siphon. The advantages of siphon-type subsurface drainage are not only prominent in quart sand but also applicable to field soil. The results of this study could provide technical support for the application of flooding and waterlogging removal in areas where waterlogging is prone to occur and could improve the ability of agricultural production to address waterlogging disasters. • A siphon-type subsurface drainage to improve the subsurface drainage capacity is proposed. • The drainage rule of the siphon-type subsurface drainage is studied. • Effect of flooding and waterlogging removal of siphon-type subsurface drainage is revealed. • The flow rate attenuation degree of a siphon is assessed. • The performance of siphon-type subsurface drainage is validated by HYDRUS-2D model. [ABSTRACT FROM AUTHOR]

The use of recycled water as a valued resource is becoming well established worldwide as a means to support agricultural irrigation. This paper describes a case study of agricultural use of recycled water and associated mixed land-use needs in a peri-urban setting of northwest Sydney. The Hawkesbury campus of Western Sydney University has an established water recycling scheme to support both agricultural productivity and landscape amenity, along with increasing linkages to infrastructure protection from bush fire risk. Risk management strategies are described for a range of land use needs across the campus, and discussed in terms of supporting local resilience, activities of the range of communities of practice involved, and ecosystem services from the local peri-urban landscape. Conclusions are drawn in terms of risk management of agricultural water recycling as an integrative process for managing associated land use needs. [ABSTRACT FROM AUTHOR]

Does the implementation of agricultural water conservation policy necessarily bring about a reduction in agricultural water extraction? Taking China's National Agricultural Water Conservation Outline proposed in 2012 as an example, this paper uses the data of 31 provinces from 2000 to 2019, and employs an empirical strategy of Difference-in-Differences (DID) to estimate the impact of the agricultural water conservation policy on agricultural water extraction. The results show that the agricultural water conservation policy does not achieve the decline of agricultural water extraction, but increases agricultural water extraction. When addressing contemporaneous water-related policies or estimating in subsample, these results are robust. The possible reason for this phenomenon is that the agricultural water conservation policy promotes agricultural production, especially by increasing the sown area and irrigated area, and the expansion of irrigated area is the main reason for the increase in agricultural water extraction. Moreover, land potentiality for crop production may affect the water-saving effect of the agricultural water conservation policy, in which provinces with higher land potentiality will have less increase in agricultural water extraction caused by the agricultural water conservation policy. Therefore, with the empirical evidence from China, agricultural water conservation policy may not necessarily reduce agricultural water extraction, and this phenomenon is always regarded as rebound effects. In order to avoid the adverse impacts of the rebound effect, agricultural water-saving technologies can be strengthened in areas with high land potentiality for agricultural production, and market-oriented policies, such as water rights reform, can be employed to avoid excessive use of water resources in areas with severe over-extraction. • Water-saving effect of agricultural water conservation policy is estimated. • Agricultural water conservation policy increases water extraction. • Possible reason for increase in agricultural water extraction is clarified. • Increase in agricultural water extraction is interpreted as rebound effects. [ABSTRACT FROM AUTHOR]

• We introduce a hydro-economic model for agricultural groundwater management. • MOD$$AT integrates economic, hydrologic and agronomic model components. • Application of MOD$$AT shows how a pumping tax impacts groundwater levels and profits over time. • The benefits of a pumping tax are spatially heterogeneous. In this paper, we introduce a hydro-economic modeling framework for the management of groundwater resources that are used for irrigated agricultural production. The model, MOD$$AT, can be used to study the costs of aquifer depletion and the net benefits of specific aquifer management policies. MOD$$AT is composed of three components, namely, an economic component, a hydrologic component and an agronomic component. A main goal of this paper is to introduce the hydro-economic model and describe how it can be transferable to different contexts. With this objective in mind, we describe model components step-by-step so that the process of integration can be replicated easily. We then apply the model to study the efficacy of a pumping tax in Finney County, Kansas, USA, which overlies the High Plains Aquifer. The results show that a pumping tax results in an increase in average well capacities in the county over time relative to the status quo, which increases the average profitability of agricultural production. However, the increase in profitability is not uniform across producers and some producers gain more than others under the tax. [ABSTRACT FROM AUTHOR]

Agricultural water use in heavily irrigated regions can reduce surface water flow. The most remarkable hydrological change in recent times in Central Asia is the rapid dry-up of the Aral Sea. In this paper, the evolution of agricultural development was traced back to the 1910s, Land-Water-Food (LWF) nexus in Central Asia was evaluated, and the relationship between agricultural development and Aral Sea dry-up was built. It was noted that for the 1910–2010s, the harvested land area in the region expanded nearly two folds — from 7.2 to 21.6 million ha. Production of cereal crops increased over eight folds — from 4.0 to 37.6 million tonnes. Cotton production reached 5.5 million tonnes, a seven-fold increase. The high increase in productivity was driven by increasing agricultural irrigation since the 1950s. Irrigation water requirement for the five main crops (wheat, cotton, maize, barley and rice) increased by about 50%; from 64.3 km3 in the 1950s to 95.9 km3 in the 2010s. Cotton and wheat were the top two crops, with respective total irrigation water use of 66.9% and 16.4%. For the study area, LWF nexus was quantified in terms of production efficiency using the data envelopment analysis method, and it was shown that excess water and land resources made agricultural production inefficient. Analysis of the irrigated area and the Aral Sea water surface area suggested that for every 1.0 km2 increase in irrigated land area, water surface area in the Aral Sea declined by 1.2 km2. The analysis of LWF tradeoff was key not only for sustainable land, water and ecological management, but also for food production in degraded arid lands around the globe. • A nexus analysis showed the tradeoff among land, food, water and the Aral Sea. • There was production increase of 7–8 folds and cultivated area increase of 2 folds since the 1910s. • Irrigation water requirement increased by 50% since the 1950s. • For 1.0 km2 increase in irrigated land, the Aral Sea water area shrank by 1.2 km2. [ABSTRACT FROM AUTHOR]

Addressing irrigation water efficiency continues to emerge as one of the potential solutions to minimize irrigation water use, improve water quality, and enhance soil health. Despite the clear importance of financial information in decision‐making regarding adoption of irrigation tools, little information is available regarding the profitability outlook of such adoption. Lack of assessment of costs and returns could lead to producers resisting adoption citing profit reductions. Hence, a cost-assessment using the financial information is necessary to evaluate the tools’ economic outlook. By using long-term projections of input prices, crop yield, and crop prices, this paper develops a financial analysis of irrigation using surge valves by calculating annual cash flows and net present value. The analysis is based on demonstration plot results and anecdotal estimates related to water savings and yield improvements in corn and soybeans in Louisiana and Mississippi. The positive estimates for net present value indicate that an investment in irrigation efficiency improvement is an economically sound choice. These estimates can enhance the adoption of irrigation‐efficiency improvement practices by providing an initial understanding of the overall profitability independent of short-term management decisions. [ABSTRACT FROM AUTHOR]

Irrigation is an essential component of crop production to meet retailer demands for premium quality when rainfall is insufficient. Under drought conditions, irrigation can be constrained by water resources availability, with consequent impacts on yield, quality and revenue. Whilst most agriculture in Europe is rainfed, greater dependence on supplemental irrigation could become more important in humid environments due to a changing climate with greater rainfall uncertainty and higher frequency of droughts. By combining industry and farm level economic data, with geospatial information on agricultural land use, agroclimate, soils and irrigation practices within a GIS, this paper estimates the total financial benefit of outdoor irrigated production in England and Wales assuming no constraints in resource availability and optimal irrigation practices. The analysis suggests that the total net benefits of irrigation in a ‘design’ dry year are around £665 million, with an average irrigation water productivity in excess of £3.3 per m 3 (close to £1.1 per m 3 excluding soft fruit). Map outputs highlight significant regional differences in water productivity reflecting the composition of land use and the importance of crop mix in determining economic value. A sensitivity analysis to changes in agroclimate, market conditions (crop prices) and water supply (costs) illustrates how the benefits might change under contrasting scenario. The study highlights the importance of supplemental irrigation, even in a humid climate, and the risks that future droughts and/or constraints in water resource availability might have on agricultural systems, livelihoods and the rural economy. The implications for water resources and drought management are discussed. [ABSTRACT FROM AUTHOR]

Water scarcity has become a worldwide phenomenon as a result of climate change. For that reason most countries are adopting various measures to reduce the impact of water scarcity on their agricultural sector and Ghana is no exception. Ghana's agricultural sector is the backbone of the rural economy in the country. The agricultural sector employs about 90 percent of the rural population and contributes extensively to the GDP of the country. But, low productivity and inefficient water use have resulted in a significant threat to the livelihoods of the rural population. The paper used a programing model named MATA (Multi-Analysis Tool for the Agricultural Sector) to achieve the stated objectives. The main objective of the study was to find out the impact of water-pricing policy on the demand for water resources by the farmers in relation to their cropping activities and income. The results of the study indicated that water-pricing policy has a negative impact on the demand for water resources in Ghana. But this impact happens only when water prices are increased significantly. However, if water prices are high it has a negative impact on cropping activities, farmers’ income, employment and crop varieties. Hence the study recommends that in order to at least reduce water wastage in the sector, it be proposed that a price (around 2 cedi/m 3 ) might be of significance in order to make farmers conscious of the scarcity of water resources, and to persuade them to adopt water saving technologies without affecting crop distribution. The study also recommends that water-pricing policy should not be used as a policy tool on its own but should be used together with other water saving policies in order to achieve the best results. [ABSTRACT FROM AUTHOR]

The 2011 and 2012 droughts considerably affected the Ogallala Aquifer supplying irrigation water for agricultural production in the US High Plains (HP). Shrinking water resources and growing demand for water create a challenging tradeoff situation. This also poses a question about the value of water and efficient water allocation. Currently, water rates for irrigating crops paid by farmers do not reflect the actual value of water that can be expressed solely as a shadow price. Also studies are missing that would comprehensively compare different states and different crops in one methodological framework. This paper helps to fill this gap. Farm-budget residual valuation is applied to estimate the shadow price of water for irrigation in three High Plains states: Texas, Kansas and Nebraska, for five prevailing crops: corn, cotton, sorghum, soybean, and wheat. Among the analyzed High Plains states the highest shadow price of water was found for wheat production in the Texas Northern High Plains ($865.99/af = $0.70/m 3 ), while the lowest shadow price was found for corn in the Texas Southern High Plains ($5.13/af = $0.004/m 3 ). The study can be helpful to stakeholders and policy makers to evaluate scenarios and tradeoffs between profitable crop production and conservation of water resources. [ABSTRACT FROM AUTHOR]

There is a knowledge gap and limited tools to readily identify trade-off relationships between competing economic and environmental goals, and between the upstream and downstream areas, of river basins. In this paper we aim to construct the trade-off relationship between midstream agricultural development and downstream ecosystem sustainability at the basin scale, using the Heihe River basin as an example. An improved top–down method was developed to understand the impacts of land use change on catchment hydrology. Based on this, trade-off relationships between cereal production in the midstream area and the runoff flowing downstream, and between cereal production in the midstream area and ecosystem service values in the downstream area, were constructed. The results showed that from 1960 to 2000 every 1000 t of increased cereal production in the midstream area (Zhangye catchment) was at the expense of 0.52 million m 3 of runoff flowing to downstream and $0.052 million of ecosystem service values in the downstream area (Ejina oasis). The analysis also showed that water productivity increased six-fold in the recent study period which greatly offset the trade-off impacts on downstream ecosystem sustainability. Linking conventional trade-off analysis involving competing economic and environmental goals to a simplified hydrological model and remote sensing image analysis to determine land use is a useful tool for integrated river basin management and will enable more transparent, informed, and inclusive water governance. [ABSTRACT FROM AUTHOR]

Nitrogen is essential to improving agricultural production systems, explaining why the contamination of groundwater by this nutrient is widespread. The aim of this paper was to describe data collected over 9 years on estimated leaching levels using a simple computation procedure and measurements of soil water content and water balance, nitrate concentrations in drainage water and meteorological data, and to assess the impacts of the duration of the grassland phase and the level of nitrogen fertilization on grassland on the drainage water quality. The study was carried out at a site of the Long-term Environmental Research Observation and Experimentation facility (SOERE) for Environmental Research- Agro-ecosystems, Biogeochemical Cycles and Biodiversity, run by the INRA experimental unit of Lusignan. The experimental treatments were sequences of maize, wheat and barley with different grassland rotational periods (a pure arable crop rotation; three or six years of grassland receiving high-level nitrogen applications; six years of grassland with a low N application rate and long-term grassland with nitrogen application). The study covered the period from April 2005 to June 2013, during which most drainage occurred in the autumn and early winter. Treatments with the longest duration of grassland exhibited less drainage than those containing a higher proportion of arable crops. The average nitrate concentration was 52.7 ± 38.63 mg NO 3 L −1 under a pure crop rotation, compared to 14.9 ± 14.76 mg NO 3 L −1 under a permanent grassland treatment. There were significant differences ( P < 0.0001) in cumulative nitrogen leaching between the different cropping systems, ranging from 9 to 37 kg N ha −1 year −1 . The introduction of mowed grassland sequences into this arable crop rotation caused a marked reduction in the nitrate levels in groundwater, and the greater the proportion of grassland within the rotation the more markedly was the NO 3 − concentration reduced, whatever the level of N fertilization during the grassland sequence. [ABSTRACT FROM AUTHOR]

There is growing scientific interest in the potential role that precision irrigation (PI) can make towards improving crop productivity, and increasing water and energy efficiency in irrigated agriculture. Most progress has been made in arid and semi-arid climates for use in high value crop production where irrigation costs coupled with concerns regarding water scarcity have stimulated PI innovation and development. In temperate and humid climates where irrigation is supplemental to rainfall, PI is less developed but nevertheless offers scope to make more effective use of rainfall, help reduce the non-beneficial losses associated with irrigation (deep drainage, nitrate leaching) and provide farmers with evidence to demonstrate environmentally sustainable practices to processors and retailers. This paper reports on recent experiences in developing precision irrigation in UK field-scale agriculture, drawing on evidence from field research and modelling studies. By combining data from these sources, a critical evaluation focusing on selected technical, agronomic and engineering challenges that need to be overcome are described, including issues regarding PI scheduling, and the delineation of irrigation management zones to ensure compatibility with existing methods of overhead irrigation. The findings have relevance to other countries where irrigation is supplemental and where precision agriculture is gaining popularity. [ABSTRACT FROM AUTHOR]

Crops For the Future Research Centre (CFFRC) is currently developing CropBASE—a cross-cutting web-based platform for decision support and knowledge sharing on underutilised crops and their end uses. It provides a quantitative basis to compare underutilised crop productivity and resource-use-efficiency with that of major crops and cropping systems under current and future climate scenarios, and will include interactive tools to integrate underutilised crop data with geo-referenced information in existing and new databases. Specific crop application models form the analysis engine of CropBASE, including crop-climate, crop-quality, crop-economic models to assess agroecological suitability, nutritional value, livelihood or food security potential of underutilised crops and products at field, farm and regional scales. A geospatial information system framework will link currently available climate databases as input data for crop models. CFFRC, already using major models for a range of crops around the world under the AgMIP program, will spearhead the inclusion of specific underutilised crops into recognised crop models. After briefly introducing CropBASE, this paper presents use cases as examples comparing yield and water productivity predictions for bambara groundnut (an underutilised African legume) and pearl millet (an alternative major cereal) under current and future climate scenarios in contrasting sub-Saharan African locations. [ABSTRACT FROM AUTHOR]

Shallow water-tables strongly influence agro-ecosystems and pose difficult management challenges to farmers trying to minimize their negative effects on crops and maximize their benefits. In this paper, we evaluated how the water-table depth interacts with rainfall and sowing date to shape maize performance in the Western Pampas of Argentina. For this purpose, we analyzed the influence of water-table depth on the yields of 44 maize plots sown in early and late dates along eight growing seasons (2004–2012) that we rated as dry or wet. In addition, we characterized the influence of the water-table depth on intercepted radiation and crop water status by analyzing MODIS and Landsat images, respectively. The four conditions we evaluated (early sown-dry growing season, early-wet, late-dry, late-wet) showed similar yield response curves to water-table depth, with an optimum depth range (1.5–2.5 m) where yields were highest and stable (∼11.6 Mg ha −1 on average). With water-table above this range, yields declined in all conditions at similar rates ( p > 0.1), as well as the crop water status, as suggested by the Crop Water Stress Index, evidencing the negative effects of waterlogging. Water-tables deeper than the optimum range also caused declines of yield, intercepted radiation and crop water status, being these declines remarkably higher in early maize during dry seasons, evidencing a greater reliance of this condition on groundwater supply. Yield in areas with deep water-tables (>4 m) was significantly reduced to between a quarter and a half of yields observed in areas with optimum water-tables. Rainfall occurred around flowering had a strong impact on maize yield in areas with deep water-tables, but not in areas with optimum depth, where yields showed high temporal stability and independence from rainfall in that period. Our study confirmed the strong influence of water-table on rainfed maize and provides several guidelines to help farmers to take better decisions oriented to minimize hydrological risks and maximize the benefits of shallow water-tables. [ABSTRACT FROM AUTHOR]

Irrigation is essential for agricultural production in semi-arid areas, but it is also an important consumer and contaminator of water. Therefore, it is necessary to improve the efficiency of water and nitrogen use. This paper analyzes the relation between nitrogen fertilization practices, irrigation and the nitrate concentration in the drainage waters of the sprinkler-irrigated LASESA district (LD) in Northeast Spain. The methodology is based on developing water and nitrogen balances in the seven main basins that drain LD (9980ha) from November 2008 to October 2010, covering the agricultural campaigns of 2009 and 2010. The results show that the hydrological properties of each basin determine the evolution of the flow of and nitrate concentration in drainage waters. In basins with soils located on Quaternary terraces, the drainage fraction (DF) and the concentration of nitrate are 22% and 120mgL-1, respectively, and the annual mass of nitrogen exported is 64kgha-1. In those with soils located on Tertiary marls and sandstones, the lower DF and nitrate concentrations (9% and 90mgL-1) lead to an annual mass of exported nitrogen which is five times lower (12kgha-1). The excess of irrigation and fertilizer use in corn make this crop the main source of nitrogen pollution. In recent years, corn fertilization has been reduced. Nevertheless, 26% of the nitrogen applied as mineral or organic fertilizer is still lost in the drainage water. [ABSTRACT FROM AUTHOR]

Flood-based Agricultural Systems (FAS), which rely on temporary floods, provide livelihoods for nearly 50 million smallholder farmers across water-stressed African basins. This paper analyses the impact of externally driven agricultural production and productivity improvement interventions in FAS, taking the Ethiopian Fogera floodplain as a case study. Ostroms' Governing the Commons Principles were used as analytical framework. Field data was gathered through focus group discussions and interviews with 266 farmers and pastoralists, and 10 local administration staff, while the AquaCrop model was used to simulate maize yield under varied floodwater management and farming practices. The interventions in the Fogera floodplain replaced vital maize and teff food crops with high-return upstream rice cultivation. It has characteristics similar to other interventions across Africa: 1) inadequate integration of local agricultural water management practices; 2) narrow focus on short-term economic gains and insufficient attention to long-term sustainability of livelihoods and environmental issues; and 3) lack of detailed ex-ante analysis of basin-wide consequences – it failed to prioritize the needs of downstream vegetable producers and pastoralists using shallow wells. The intervention missed several low-cost opportunities, including the establishment of rules to protect downstream water rights; the construction of gabion-strengthened on-farm structures to efficiently distribute floods or raised brick-walls to reinforce shallow wells; and the implementation of measures for improved soil fertility and weed management. The study establishes that these missed opportunities could have enhanced livelihoods by doubling rice yield to 6 tons/ha; increased teff and maize harvests by one-third, to 3 and 5 tons/ha respectively; and mitigated 25% vegetable yield loss and 40% reduction in grazing land. These opportunities could have also produced environmental benefits, including reduced soil moisture and fertility depletion. Lessons from the Fogera floodplain on making interventions cost-effective and considering basin-wide livelihood impacts are relevant to FAS globally. • Analysed external improvement interventions in Flood-based Agricultural Systems. • Farmer-led systems have fair floodwater sharing, but low agricultural productivity. • Implemented interventions have not improved floodwater management and productivity. • Many low-cost improvement opportunities missed due to lack of basin-wide approach. • Identified affordable and up-scalable basin-wide livelihood improving interventions. [ABSTRACT FROM AUTHOR]

Countries dependent on small-scale agriculture, such as Bangladesh, can be vulnerable to the effects of climate change and variability. Changes in the occurrence and severity of drought are an important part of this issue and form the subject of this paper. We examined the characteristics of meteorological drought occurrence and severity using the Effective Drought Index (EDI), including the drought events, drought chronology, onset and ending of drought, consecutive drought spells, drought frequency, intensity and severity, using North-Bengal of Bangladesh as a case study. The rainfall and temperature dataset of the Bangladesh Meteorological Department (BMD) for the study region throughout 1979–2018 is utilised. The trends of drought are detected by using the Mann-Kendall test and Sen Slope estimation. We evaluated the performance of EDI using the Standardized Precipitation Index (SPI), historical drought records and rice production. This study finds that seasonal and annual droughts have become more frequent over the period studied in all seasons except the pre-monsoon. In addition, the largest decrease in seasonal EDI is found in the monsoon, both in the Teesta floodplain and Barind tract regions. In the decades prior to the late 2000s, a drought spell typically starts between March and May (±15 days) and ends with the monsoonal rainfall in June/July. In the years since the late 2000s, monsoon and post-monsoon droughts spells have significantly increased. Overall, the peak intensity of droughts are higher in the Barind tract than in the Teesta floodplain, and the frequency and severity of moderate to severe drought are increasing significantly in the Barind tract. The drought frequency has increased by at least 10% in North Bengal of Bangladesh over the periods of 1979–2018. Though EDI is strongly correlated with the SPI index, our analysis shows that, surprisingly, rice production is actually decoupled from meteorological drought (as identified by the EDI and SPI). Hence, this research suggests that there are other significant influences on rice yield beyond meteorological drivers. This could include effects from differing irrigation infrastructure, technology and management strategies in the study regions. Challenges to agricultural production may be exacerbated in coming years, should the identified increasing meteorological drought trends continue. The data that support the findings of this study are available on request from the corresponding author. [Display omitted] • All seasonal and annual drought severity except pre-monsoon is increasing. • Moderate to severe drought is increasing more in the Barind tract than in the Teesta floodplain. • Drought spell typically starts between March and May (±15 days) and ends with monsoonal rainfall. • EDI and rice production have no strong linear relationship. [ABSTRACT FROM AUTHOR]

Increasing agricultural productivity through irrigation technologies is recognized as an effective way to improve smallholders' livelihoods and food security in developing countries. However, most smallholder farmers do not have access to irrigation technologies. Using a double-bounded contingent valuation survey data from smallholders in Ethiopia and probit and bivariate probit models, this paper analyzes smallholder farmers' demand for agricultural water lifting technologies (WLTs) and the factors affecting the demand for these technologies. Assessment of farmers' preferences among three water lifting technologies available in local markets (motorized pump, rope and washer and pulley) show that farmers prefer motorized pumps to pulley or rope and washer technologies. Use of motorized pumps is more efficient and save labour than pulley or rope and washer technologies. However, results show that smallholders are constrained by inadequate access to financing options to adopt more efficient and labour-saving water lifting technology and hence operate below the production possibility frontier. Enhanced access to finance could help ease this constraint and allow smallholders to acquire more efficient irrigation technologies, enhance adoption and improve productivity. With a growing population pressure and land fragmentation in rural Ethiopia, the livelihoods of smallholders depend mainly on the meagre land endowment they possess. Increasing the productivity of land using yield enhancing technologies, particularly multiple cropping per year via small-scale irrigation is key to improve their livelihoods. Targeted interventions are thus warranted to mitigate the key adoption constraints such as improving access to credit and technical know-how of smallholders. • We analyze smallholder farmers demand for irrigation water lifting technologies. • Supply and demand side credit-constraints are key determinants of adoption and demand for irrigation technologies. • Farmers prefer motorized water pumps to pulley and rope and wash technologies. • Farmers with smaller landholdings require targeted interventions for improving their access to irrigation technologies and land productivity. [ABSTRACT FROM AUTHOR]

Climate variability and changing cropping patterns are two main factors directly influencing catchment hydrological processes and agricultural productivity. Assessing the response of hydrological processes and agricultural production to the combined impacts is of great importance for enhancing water resources management, water productivity and agriculture sustainability. SWAT (Soil and Water Assessment Tools) models embedded with 2007 and 2018 land use were built for the San Joaquin watershed (SJWS) in California's Central Valley. Global sensitivity analysis were conducted to select parameters that have the largest influence on evapotranspiration (ET) processes. The model was calibrated and validated produced good agreement for monthly ET from remote sensing and yield of 8 major crops using county level reported yields during the periods of 2001–2009 and 2010–2018. Based on the outputs of the calibrated SJWS SWAT model, regional ET showed a significant increase, which was caused by rises in temperature and changing cropping patterns associated with increase in area under nut crop production. Seven major crop yields increased excluding alfalfa, implying that the impacts of increasing temperature and small decreases in precipitation were not dominant factors in explaining observed changes in yield. From periods 2001–2009–2010–2018, total water productivity (WP) increased slightly from 2.11 to 2.15 kg/m3, associated with more water-intensive permanent crop production systems. Total economic water productivity (EWP) increased significantly by 111% from 0.55 to 1.16 US$/m3, which also indicated the substantial economic benefit brought to the SJWS by expanding the land area under high-EWP crops such as nut crops and vegetables. Nutritional water productivity (NWP) for energy, protein and fat were reduced from 1211 kcal/m3, 183 g/m3 and 105 g/m3 to 1141 kcal/m3, 111 g/m3 and 88 g/m3 during the period 2010–2018 mostly due to high water use. Total NWP for calcium was increased from 114 to 145 mg/m3, respectively. This study provides initial insights into the response of WP, EWP and NWP to the changing cropping patterns and climate variability for major crops in the SJWS, which could be used by a wide range of stakeholders including farmers, commodity boards, irrigation districts, groundwater sustainability basins, environmental justice groups and policy makers to optimize water resources planning and management. We recommend creating a comprehensive index that incorporates WP, EWP and NWP for making sustainable water resources planning and management decisions. • Climate variability and cropping patterns change were analyzed from 1999 to 2018. • Regional evapotranspiration significantly increased over the past twenty years. • Total WP only increased slightly for the low WP of nut trees and its extended area. • Total EWP increased significantly by 111% from 0.55 to 1.16 US$/m3. • The paper also explores changes in NWP for various crops grown in the watershed. [ABSTRACT FROM AUTHOR]

• climate change will trigger a strong increase in temperature in Central Asia. • discharge is expected to increase in early spring and decrease in summer. • projected changes may put spring crops under stress while winter cereals may benefit. • adjusting of planting and irrigation calendar may help in adapting to future changes. Understanding of future climate change impacts and successful planning of adaptation measures are of vital importance for Central Asia given the region's economic vulnerability, dependence on scarce water resources, and observed above global average warming rates. This paper analyses how impacts of climate change on the hydrological regimes and temperature patterns could affect the irrigated agricultural production in two case study areas, the Aspara and Isfara river basins. The methodology applied is based on analysis of temperature indicators and current cropping calendars in target locations combined with hydrological simulations by the process-based Soil and Water Integrated Model (SWIM) of the two river basins. The selected climate change projections comprise the moderate and high emissions scenarios - RCP4.5 and RCP8.5. The results reveal that climate change will create unfavourable conditions for irrigated spring crops, due to decrease of discharge during the vegetation period. On the other hand, the projected shift of peak discharge to an earlier date offers benefits for irrigated winter cereals, providing more water for irrigation in spring. Results suggest that, there is an opportunity to adapt the irrigated agricultural production in the selected regions by fitting the cropping calendars to changing vegetation periods and to the timing of peak discharges. [ABSTRACT FROM AUTHOR]

• Profitability of soil and water conservation practices vary with seasons. • During masika , profitability can still be achieved by growing crops as rainfed. • It's unprofitable to grow maize and beans on terraces as irrigated in rainy seasons. • Combining SWC techniques with auxiliary practices can enhance profitability. Soil and water conservation techniques are known to be profitable and widely promoted in sub-Saharan Africa. However, how their profitability vary across cropping seasons has not been fully explored. Thus, farmers are often faced with the dilemma of which agricultural technique(s) and/or combination(s) thereof to implement in which cropping seasons, and for which crops to maximize profits. In this paper, we investigated the profitability of two soil and water conservation techniques (terraces and borders) and compared them against the conventional flat cultivation in Makanya catchment Tanzania. Farmers in the area grow maize, beans, lablab and cowpeas over three cropping seasons (locally called masika , vuli and chamazi/kipupwe). Based on field survey of 382 farmers in 2019, it was found that aggregate yields were generally higher on fields with intercrop than those with monocrop with more than 0.5 ton/ha of total grain yields. Borders were generally more profitable (399 USD/ha) than terraces and flat cultivation during all three cropping seasons while flat cultivation was more lucrative during the masika than vuli season. Terraces was only lucrative for rainfed beans with Benefit Cost Ratio of 1.5 (208.7 USD/ha) and 1.2 (90.5 USD/ha) in masika and vuli respectively. Beans grown on borders during chamazi season had the highest profitability with Benefit Cost Ratio of 1.9 (399 USD/ha) compared to terraces and flat cultivation in all three cropping seasons. Whereas it was more profitable to grow maize, beans and lablab on borders, farmers could still realize appreciable profits by growing these crops as purely rainfed on flat cultivation especially during the masika season. It was concluded that in semi-arid zones, soil and water conservation techniques used in combination with other auxiliary practices such as irrigation, intercropping with legumes, mulching and manure application could greatly enhance profitability, but that depends on cropping season and market factors. [ABSTRACT FROM AUTHOR]

• The impact of Chinese policies on soil and water conservation on domestic agricultural development were explored • The effects of investment in soil and water conservation and agricultural production in Zhejiang Province were analyzed • The performance of soil and water conservation construction had a significantly positive impact on the agricultural outputs. Water and soil resource are fundamental natural resources and one of the determinant factors of the ecological environment. Soil erosion not only affects economic development, but also triggers the occurrence of natural disasters that threaten people's property and lives. Therefore, it is necessary to take various and effective measures and technologies to protect water and soil resources, to promote rapid and stable economic development, and to protect people's livelihood. This paper explores the impact of related policies on soil and water conservation in China in recent years on domestic agricultural development, and analyzes the effects of investment in soil and water conservation and construction on agricultural production in 11 cities in Zhejiang Province, from 2007 to 2016. The empirical results show that the performance of soil and water conservation construction in Zhejiang over the years fell in the range between 0.4 and 0.6, and the overall efficiency value and productivity changes began to decline after the year of 2015. Secondly, mixed cross-sectional data analysis and panel data analysis showed that the performance of soil and water conservation construction had a significantly positive impact on the agricultural outputs (log (Output1)) in each city. [ABSTRACT FROM AUTHOR]

• Increasing drought drives need for mitigation technologies. • Drought mitigation technologies include antitranspirants. • These are substances sprayed on crops to reduce transpiration. • Various antitranspirant mechanisms, but all increase plant water status. • Antitranspirants applied at sensitive growth stages can improve crop yield. About 80 % of global farmland is under rain-fed conditions and most of it is prone to drought, which limits crop productivity. Due to climate change, drought will become more frequent and severe, threatening world food security. Antitranspirants, materials that reduce transpiration, could potentially result in greater food production by realising more of a crop's potential yield during drought. Despite antitranspirants reducing photosynthesis, research has shown that they can mitigate drought stress and increase grain yield. Although this paper is not restricted to specific years, part of it is a systematic review of 173 original research articles published between 2009 and 2018. Overall, the analysis suggests that interest in the potential of antitranspirants is growing. One major achievement in antitranspirant research during the past decade was establishing the optimal timing of application of the substances, which is linked to reproductive processes most vulnerable to drought. Despite research evidence of the efficacy of antitranspirants in ameliorating drought stress, they are not widely used for commercial arable crop production. However, in fruit horticulture, products with antitranspirant effects are already being used commercially for various non-antitranspirant purposes. More recent research shows that with knowledge of a crop's growth stage and soil moisture, antitranspirants can be a valuable option for managing drought impacts on yield in arable crops. [ABSTRACT FROM AUTHOR]

• Irrigated producers consider groundwater as a fixed input. • Crop price expectations generally have no impact on groundwater use. • Only a small portion of rainfall is effective. The Ogallala Aquifer is the main water resource for irrigated agricultural production in much of Western Kansas. It is hypothesized that as crop price expectations increase, producers will apply more water to increase yields in order to maximize profit. Using field-level panel data on groundwater pumped for irrigation in Western Kansas, this paper examines whether irrigated producers' groundwater pumping decisions are consistent with the profit maximization framework by empirically testing if crop price expectations have a positive impact on the quantity of groundwater pumped. In general, the empirical results indicate that crop price expectations have no statistically significant impact on the quantity of groundwater pumped per acre. This suggests that groundwater pumping decisions are not consistent with the profit maximization framework and that irrigated producers consider groundwater as a fixed input possibly due to limited availability of groundwater in the area. Our econometric analysis also suggests that only a small portion of rainfall is effective. [ABSTRACT FROM AUTHOR]

• Effects of main tillage practices on crop yield, water consumption and water use efficiency of wheat and maize in Northern China were evaluated. • Subsoiling (SS) increased crop yield but consumed more water, and is suitable for winter wheat and summer maize in North-central China. • Mulching (M) significantly increased crop yield and conserved more soil water. • Ridge and Furrow Planting with Mulching (F–M) increased both wheat and maize yield, and was of more beneficial for maize than wheat. • M and F–M are suitable for spring maize in North-central China as well as wheat and maize in Northwest and Northeast China. Water deficiency seriously restricts the agricultural production in Northern China. Soil tillage practices can conserve water and increase yield effectively, but the regional applicability of soil tillage practices has not been systematically studied so far. It is significant to study the regional characteristics of tillage practices on water-conserving and yield-increasing so that the optimal practices for improving the crop water production and maintaining the agricultural sustainable development can be determined. This study applied the meta-analysis method to analyze results extracted from 156 peer-reviewed published papers conducted at 62 agricultural experimental sites for evaluating the effects of commonly used tillage practices, i.e., No-tillage (NT), Subsoiling (SS), Mulching (M), Ridge and Furrow Planting without Mulching (F), and Ridge and Furrow Planting with Mulching (F–M) on crop yield, water consumption and water use efficiency (WUE) of wheat and maize in Northern China. The results showed that NT only increased yield of winter wheat in North-central China and spring maize in Northeast China. SS increased wheat and maize yield by 16.3 ± 3.2 % and 9.2 ± 3.0 %, and increased water consumption by 8.4 ± 3.4 % and 1.8 ± 1.8 %, respectively. M increased the yield of wheat and maize by 14.9 ± 2.9 % and 17.7 ± 6.2 %, respectively, while it did not increase the water consumption. F increased the yield of wheat by 5.0 ± 1.1 %. F–M increased wheat and maize yield by 18.9 ± 6.3 % and 36.6 ± 11.8 %, respectively. This study recommends that, SS is suitable for winter wheat and summer maize in North-central China. M and F–M are suitable for spring maize in North-central China as well as wheat and maize in Northwest and Northeast China [ABSTRACT FROM AUTHOR]

• 546 trials from different experiments based on crop WUE were considered. • Summer crops showed higher WUE than winter crops. • Maize was the most water use efficient crop under optimal growing condition. • Sorghum was the most efficient under semi-arid and arid conditions. • Crops were the most significant water use efficient crop on clayey soils. Water is a limiting natural resource for agricultural production. While it is well accepted that crop types differ in their water use efficiency (WUE), there is no consensus on the main factors affecting WUE of main field crops, which was the motivation of the current study. The effects of rainfall pattern, soil type and climatic regime on crop WUE were evaluated using data from 514 experiments around the world published in ISI journal papers. The results confirmed that crop type had a significant effect (p < 0.05) on WUE with cereals producing on average 2.37 kg of dry grain per cubic meter (m−3) of water followed by oilseeds (0.69 kg m−3), fibre crops (0.45 kg m−3) and legumes (0.42 kg m−3). Amongst cereals, maize (3.78 kg m−3) and sorghum (2.52 kg m−3) were more water-use efficient than wheat (1.02 kg m−3), barley (1.21 kg m−3) and millet (0.47 kg m−3). Overall, maize was the most water use efficient crop under well-watered conditions (9.90 kg m−3), but sorghum was the most efficient under dry conditions (5.99 kg m−3). WUE of crops increased from desert to tropical through sub-tropical climate. Moreover, WUE tended to correlate positively with soil organic carbon content (r = 0.86) and negatively with clay content (r=−0.78) and soil bulk density (r=−0.85). These results provide information that is important for making decisions on crop selection in a context of increased climate variability and for crop variety development with enhanced WUE. However, there is need for more research to gain more understanding of the mechanisms responsible for the observed trends and causes of the unexplained variability. [ABSTRACT FROM AUTHOR]