The evapotranspiration (ET) and crop coefficient (Kc) spatial variabilities are disregarded in traditional methods of evapotranspiration estimation based on lysimeters. With the development of remote sensing techniques, the estimative of ET on agricultural areas, in a specialized way, has become possible through the use of algorithms based on the surface energy balance such as the METRIC and its automated version, featured on the Google Earth Engine Evapotranspiration Flux (EEFlux) platform. This study was carried out at a center pivot irrigated area located in the city of Primavera do Leste, MT, Brazil. One growing season (2016) of the specie Zea mays (maize) was analyzed. Using processed images from the Landsat 8 satellite, within the EEFlux platform, the spatial variability of the actual evapotranspiration (ETa) and the Kc curve of this crop was determined. The water use efficiency (WUE) was also determined. A comparative analysis was performed using different statistical indices: root mean square error (RMSE), the mean bios error (MBE) and the index of agreement (d). The ETa for maize ranged from 1.3–4.1 mm d−1 and the Kc obtained ranged from 0.3 to 1.2. The average WUE of maize was 1.13 kg m-3. The method of estimation of ETa and Kc spatialized using the Google EEFlux platform made possible the understanding the spatial variability of these two variables and, therefore, this application has high potential to estimate the ETa and Kc on different stages of maize crop growth cycle.

Maize (Zea mays L.) is an important cereal crop grown worldwide. With the increase in human food demand but limited land and water resources, precise spatially explicit knowledge about the maize production capacity through agricultural management practices (e.g., using recommended nutrient and water inputs, RNWI, by local agronomists) is essential to guide the future policy, research, development, and investment. Here, we used a well-validated crop model (APSIM-Maize) for 1981–2010 combined with actual climatic and soil data to estimate maize yield improvements under RNWI in three main cropping regions in China (the North China Spring Maize Region, NCS; the Huanghuaihai Summer Maize region, HS; and the Southwest China Mountain Maize Region, SCM). Compared with the county-level maize actual yield in the three main cropping regions, the average maize yield could be increased by 33 % (4 Mg ha−1) through RNWI, while the improvements in the coefficients of variation (CVs) of grain yield and reliable grain production (RGP) were 0.11 and 32 % (69 million Mg), respectively. Except for RNWI, the average yield, CVs of yield, and RGP could still be increased by 28 % (3 Mg ha−1), 0.10, and 36 % (80 million Mg) through other management and technologies (OMT). Further analysis in four types of yield level-stability zones (high-stable, low-stable, high-unstable, and low-unstable zones) showed that greater contributions of using RNWI and OMT to improve maize grain yield, yield stability, and RGP were found in zones with low/unstable yield across the three regions. The findings highlighted the focus on increasing maize yield in low/unstable-yield zones could provide a greater return.

The study of alternate bearing based on the seasonal changes pattern of tree carbohydrate is the unreviewed issue in the loading physiology of date (Phoenix dactylifera L.) trees. On the other hand, bunch cutting back is a crop improvement practice used in the date orchards, and it is effective on flower induction and fruit set that regulates the quality and growth of fruit in the On year and the amount and yield of the produce in the Off year. Research on an alternative thinning agent with the bunch cutting back is essential for dates in order to be economical and applicable in harsh climates. For this purpose, the experiment was conducted as a combined analysis across years based on randomized complete blocks on ‘Mazafati’ dates of 10–12 years old with different loading in 2017 (Off2017, Normal2017 and On2017), as well as the On condition trees in 2017 plus bunch cutting back (On2017+Cutting back) or regulated deficit irrigation (On2017+RDI). The main objectives of this study were to investigate the fragmentation of carbohydrate reserves of the tree in the annual rotation cycle in different loading, to evaluate the relationship of sugar reserves with production and abscission of flowers and fruits, to determine the effect of the RDI application in the On year on the pattern of sugar changes, hydrolytic enzymes activity, alternate bearing, quantity and quality of the product, and the possibility of replacing it with cutting back. The results confirmed the significant effect of loading rate on the seasonal fragmentation and fluctuation of carbohydrates and the hydrolytic enzymes activity. The results also showed that the RDI treatment, due to the decrease of bunch length, reduced the biennial bearing index (BBI) and improved the qualitative and quantitative traits of fruit better than the cutting back. According to the results of this study, the irrigation condition of trees has the potential to change the marketability and abscission of date fruits and this is a pioneer study of the RDI role as a thinning potential and moderating of date alternate bearing. However, further research is needed to justify the time and duration of this treatment application.

Efficiency is one of the most important assessment indicators in irrigation systems. Classical efficiency (CE) is not an exact index due to the lack of consideration of the return flows. Therefore, the neoclassical concepts of the efficiency are considered to take a part of losses of irrigation water as a return flow into account. Quality of the return flows may change in their path and it must be considered in evaluating the efficiency and productivity of irrigation water. This research was carried out to investigate this challenge. Sustainable efficiency (SE) was applied based on the water balance and quality of return flows. The methodology and detail for computing different parameters and their quality and beneficial coefficients in water balance equation were presented. Moghan irrigation and drainage network in the northwest of Iran was selected as the study area and CE and SE were calculated in meso and micro levels using the meteorological data, cropping pattern, irrigation water volume, natural and artificial drainages, infiltration and return flow quality. In addition, the irrigation water productivity was calculated by considering the volume of water based on the different concepts of efficiency. Quality coefficient related to return flow had different values in different months (0.85 in August and 1 in November and December). The results showed that about 87 % of inflow, 91 % of the rainfall, 89 % of the evapotranspiration, 13 % of the non-reusable water, and 91 % of the return flow were useful in the study area. The highest and the lowest efficiencies are occurred in September and November, respectively. The average of meso and micro Sefficiencies were 72 % and 47.5 %, respectively, and the CE was 37.9 %. The results showed that water productivity based on the SE is more than that of the CE. The water productivity at the meso level also showed a higher value than at the micro level.

Assessment of agricultural drought risk is significant for risk division and management. Nevertheless, the drought risk dynamic evolution characteristics have not been revealed. To this end, the agricultural drought conditions are characterized by the standardized precipitation index (SPI), and the time scale of SPI is determined based on agricultural damage data. The joint return periods of various drought severities and durations under different agricultural drought scenarios are calculated by using copula functions. Moreover, drought risk factors (resilience, vulnerability, and exposure) are also used to characterize drought risk. Subsequently, based on the moving window, the joint return period and risk factors in each window are calculated, and agricultural drought dynamics are explored. The Pearl River Basin (PRB) is selected as a case study. Results indicated that: (1) the 4-month most appropriate timescale for the SPI in characterizing agricultural drought based on agricultural damage data in the PRB; (2) risk factors method is more suitable than joint return period in assessing agricultural drought risk; (3) most of the PRB exhibit a significant increasing agricultural drought risk, while the drought risk of the Pearl River Delta has a decreased trend within the past 50 years. Generally, this study show new insights into agricultural drought risk assessment, thus promoting local agricultural drought preparedness and mitigation.

Irrigation systems have in recent years attained a higher level of variety in as such that the selection and implementation of an irrigation system is based on the physical constraints of the site area thus giving way to a much more adequate irrigation efficiency. With due regards to the water crisis in Iran and subsequent drought conditions, the implementing of similar irrigation systems in different regional conditions lacks any justification. In the Izeh plain the use of surface irrigation systems with minimal efficiency is very common. In order to implement and operate modern irrigation systems and maximize water saving, the site selection of pressurized irrigation systems was evaluated through the fusing of AHP and GIS maps for a variety of pressurized irrigation systems followed by the selecting of the best irrigation system for each region. In the current study physical and socio-economic criteria were selected as the main criterion and were then classified into several sub-criterions.A Drip irrigation system, a Gun irrigation system, a center pivot irrigation system and a linear irrigation system were selected as the options utilized when using the AHP method. The Gun and center pivot irrigation systems had the least value as they were not suitable for mountainous area. Drip and linear irrigation systems were given a higher value and were suitable for implementation in most regions. After comparing different sub-criterion, the drip irrigation system was identified as being the most suitable pressurized irrigation system for the Izeh plain.

Efficient agricultural water use is required for food safety and water alleviation on a global scale. Combining the water footprint and agricultural water use paradigms and enveloping water resource movement and its impact on the environment in the agricultural production process, a hybrid framework for agricultural water utilization and efficiency evaluation was constructed in the current paper. The indicators water resources use (WRU), efficiency (WRE) and productivity (WRP) are used in this framework for the total water exploitation, the effective utilization rate and the production capacity measurement, respectively. An empirical study on the framework was conducted with major cereals (wheat, maize and rice) in 31 provinces, autonomous regions and municipalities (PAMs) of China. The national WRU, WRE and WRP values of integrated cereal were calculated to be 669.0 G m³, 0.633 and 0.679 kg/m³, respectively, from 1996 to 2015. The PAMs with high WRE values were located in southwestern, northeastern and northern China, while the ones with low values were clustered in northwestern and southeastern China. The spatial distribution pattern of WRP is consistent with precipitation. The water use efficiency (WRE and WRP) of the three specific crops in this framework increased over time. The WRE of maize was significantly higher than that of rice and wheat, while the WRP of wheat was the lowest. WRU measures the total water resource appropriation during crop growth in both quantity and quality; WRP was able to show where water use efficiency needs to be improved; and the function of WRE to indicate water saving potential could not be replaced by notable indices, such as irrigation efficiency or generalized efficiency. Therefore, further research is warranted to evaluate agricultural water use efficiency at different scales using this hybrid framework.

In the arid region of Central Asia, climate change leads not only to changes in water availability generated by glacier/snow melt in the alpine regions, but also to changes in water consumption. This paper evaluates agricultural water demand and water supply (represented by precipitation) for the five Central Asian countries (Kazakhstan, Kyrgyzstan, Tajikistan, Turkmenistan and Uzbekistan) under global warming conditions of 1.5 °C and 2.0 °C. As Central Asia is more sensitive to climate change compared to the global average, the temperature is predicted to rise by 1.7 °C and 2.6 °C and precipitation to increase by 9 % and 12 % in global warming scenarios of 1.5 °C and 2.0 °C, respectively. The average crop water requirement (CWR) is expected to increase by 13 mm and 19 mm per year, respectively, under the global warming scenarios of 1.5 °C and 2.0 °C. A widening gap between water supply and water demand is expected compared to the historical period (1976–2005) under global warming scenario of 2.0 °C. Under global warming of 2.0 °C, the anticipated water gaps between precipitation and CWR are projected to increase by 2.8 × 108 m3 and 1.5 × 108 m3 for the rainfed north Kazakhstan region and the irrigated Fergana region while the increase of precipitation could able to meet the increase in CWR under global warming of 1.5 °C. Investigating the water balance for major planting areas in water-limited Central Asia could provide a scientific basis for sustainable development of the entire region.

Aquaculture effluent irrigation has been widely adopted to replace freshwater irrigation to save water and providing additional fertilizer to the crop. There is limited information on the performance of fertilizer supply levels under fishpond effluent irrigation. The objectives of this study were to investigate the effect of reducing a rate of fertilizer on the purification of wastewater from fishponds by paddy fields and the yield of rice under fishpond effluent irrigation in central China in 2015. The treatments included 100 %, 80 %, and 60 % of the normal fertilizer rate (NFR, 150 kg N ha−1, 120 kg P2O5 ha−1 and 75 kg K2O ha−1) with fishpond (freshwater-pond aquaculture) effluent as an irrigation source, designated NFR-E, 0.8NFR-E, and 0.6NFR-E, respectively; with an additional NFR with freshwater as an irrigation source (NFR-F). The results showed that 5700 m3 ha-1 freshwater was saved by the use of the NFR-E, 0.8NFR-E and 0.6NFR-E treatments. The concentrations of total nitrogen (TN), total phosphorus (TP), dissolved phosphorus (DP), ammonia-nitrogen (NH4+-N), nitrate-nitrogen (NO3--N) and particulate phosphorus (PP) in the surface water and seepage water of the paddy field and the residual soil N and P in the 0−60 cm soil depth after the rice harvest decreased with the decreasing NFR. The removal rates of the TN in the surface water across the tillering, booting, heading and filling stages were 25.1 %, 38.9 % and 50.5 % on average for the NFR-E, 0.8NFR-E and 0.6NFR-E treatments, respectively. The corresponding removal rates of the TP were 56.4 %, 71.2 % and 76.2 %, respectively. These increased removal efficiencies were related to the lower N and P concentrations in the surface water of the paddy field and the efficient use of nutrients by rice under the reduced fertilization treatments. Compared to the NFR-F treatment, the 0.8NFR-E treatment resulted in a comparable accumulation of N and P and grain yield of rice, while decreasing the contents of N and P in the water of paddy fields and the residual soil N and P in the 0−60 cm soil depth after the rice harvest. Thus, reducing the normal fertilizer rate by 20 % could improve the water quality of the paddy field without deleterious effects on the rice yield and save 5700 m3 ha-1 of fresh water under fishpond effluent irrigation. These results can also provide a basis for in-depth understanding of the mechanism of aquaculture effluent purification through paddy field ecosystem in response to fertilizer supply levels.

Ridge-furrow farming systems with transparent plastic film have been used extensively for maize (Zea mays L.) production in semi-arid areas. However, with climate warming, problems may arise associated with premature senescence and reduced production. This study examined whether dual mulching of ridges with black plastic film and furrows with straw can delay senescence and increase summer maize yield. Summer maize cultivation experiments were conducted in 2014–2015 by ridge-furrow planting with black (BRM) or transparent (TRM) plastic film mulch over the ridge and wheat straw mulch over the furrow, flat planting with black (BM) or transparent plastic film mulch (TM), and flat planting without mulch (control treatment, CK). The objective of this experiment was to determine the effects of the different mulching treatments on soil water and temperature, evapotranspiration (ET), leaf, photosynthesis rate, yield, and water use efficiency of summer maize. The BRM and TRM treatments were superior to the BM and TM treatments in terms of soil water storage in the 0–200 cm soil profile. The BRM reduced the diurnal variation in the soil temperature and lowered the soil temperature in the root zone. The BRM treatment extended the maize reproductive growth period by 5 days compared with TM, and 2–3 days longer than for the other mulched and control treatments. The BRM also increased the leaf area and dry matter accumulation per plant while significantly increasing the leaf photosynthesis rate. Moreover, BRM increased the 100–seed dry weight and significantly improved yield and water-use efficiency. The 2–year average yield of the BRM treatment was 6.7, 13.4, 18.4, and 72.9 % greater than yield of the TRM, BM, TM, and CK treatments, respectively. The corresponding water-use efficiency improved by 11.2, 13.1, 20.3, and 72.1 %, respectively. Applying the BRM cultivation practice will effectively delay senescence and increase summer maize yield in the agricultural production area of the study region.

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.

A higher drought risk in Java Island is generally known than the other regions in Indonesia. Tracking soil moisture can be an alternative way to monitor drought rather than precipitation-based drought indices. The objective of this study was to assess root-zone water storage (defined by root-zone soil moisture contents) based on a linked approach between the generalized complementary relationship (GCR) and a single bucket model in Java Island. Since it does not require precipitation for estimating actual evapotranspiration (ETa), the GCR allowed implementation of a simple single bucket model. The ETa and root-zone soil moisture estimated in this study were compared against the Global Land Evaporation Amsterdam Model (GLEAM) and the root-zone water storage additionally compared with the European Centre for Medium-Range Weather Forecasts (ECMWF) ERA5 reanalysis data products. Overall, the GCR ETa estimates were higher than those from GLEAM, and similar patterns of the root-zone water storage were found in the comparisons of both GLEAM and ERA5. The comparative evaluation suggests a further study on the adjustment of Priestley-Taylor coefficient value in Java for better application of the GCR. The soil moisture estimated by the single bucket model and the root-zone soil moisture products of GLEAM were highly correlated (0.8 or greater Pearson correlation coefficients). Low root-zone water storage and high ETa rates were found in eastern Java relative to the other areas, indicating high water shortage risks in dry season. This study found that El Niño clearly contributed to the variability of the root-zone water storage in Java especially in wet seasons (December to February). It is also suggested that the proposed approach can be useful to operationally provide soil water availability in Java from readily available meteorological observations.

Seed priming is known to often alleviate salinity stress during seed emergence and subsequent crop growth. This study compares the effects of salinity stress on the germination and emergence of wheat (Triticum aestivum L.) seeds untreated (control) and primed with ascorbic acid (Asc), potassium silicate (K2SiO3), proline (Pro), spermidine (Spd) and Lake Urmia saline water (LUsw). Saline water from Lake Urmia (Iran) was diluted to produce salinities with electrical conductivities (EC) of 2, 4, 6, 8, 10, 12, 14, 20 dS m−1, while distilled water (EC ≈ 0 dS m−1) was used for the control. Two independent sets of experiments were conducted. The first experiments were used to select the most effective concentration of each priming agent based on the final germination percentage (GP) and germination rate (GR). The second set of experiments aimed to analyze the measured data in terms of salinity response functions in order to quantitatively determine the most effective priming agent(s). The first experiments showed that the most effective concentrations of Spd (0.5 mM), Pro (25 mM), K2SiO3 (1.5 mM) and LUsw (100 mg L−1) mitigated the negative impacts of salinity on GR by 32, 18, 17 and 22 %, respectively. The second experiment showed that the Maas and Hoffman (1977) and van Genuchten and Hoffman (1984) salinity response functions provided effective descriptions of seedling and early growth response to salinity stress. Mean values of the salinity threshold (EC*) and the salinity at which a given trait was reduced by 50 percent (EC50) in these functions were 3.4 and 10.8 dS m−1 for the control, respectively. By comparison, the EC* values for the K2SiO3, Pro, Spd and LUsw primed seeds were 5.3, 4.5, 4.7, and 4.2 dS m−1, respectively, and the EC50 values were 12.4, 11.4, 11.9, and 9.4 dS m−1, respectively. The beneficial effects of K2SiO3 on seedling growth were more evident than those of the other priming agents. K2SiO3 had the highest effect on EC* and EC50 of the vitality index (VI), showing increases of 151 and 34 %, respectively. The highest increases of EC* and EC50 for seedling dry weight (72 and 24 %, respectively) were obtained with Spd and K2SiO3. The findings provide much insight on relieving the negative effects of salinity through cost-effective seed priming operations so as to improve the production of wheat under saline conditions.

Cover crops are a potential component of agroecological cropping systems, since they may render crop rotations more sustainable. They simultaneously provide multiple ecosystem services, such as decreasing nitrate leaching, decreasing erosion, and increasing soil organic matter. However, cover crops increase evapotranspiration and reduce drainage, which results in a potential disservice for groundwater recharge. Little attention has focused on management of cover crop residues after destruction or their influence on water flux dynamics, particularly in dry and temperate climates. The objective of our study was to analyze and quantify the impact of cover crop management on soil water content and water flux dynamics to understand the main mechanisms of system functioning. We combined a two-year field experiment with crop-model simulations. We performed the field experiment in southwestern France that compared three cover crop treatments, with bare soil as the control. The treatments included (1) living cover crops lasting ca. 9 months from August-April, (2) crushing cover crops in November and leaving them as mulch on the soil, and (3) plowing up cover crops in November to promote residue decomposition and the green manure effect. The STICS soil-crop model was used to predict water fluxes that were not measured and to perform a 20-year independent simulation study based on recent climate series for the experimental site. Our main results indicated that cover crops (1) always reduce water drainage by 20-60 mm compared to that under bare soil; and (2) could significantly reduce soil water content (0-120 cm deep) for the next cash crop by a mean of 20-50 mm, and up to 80 mm in dry spring conditions, but early destruction could decrease this negative impact. The simulations clearly showed that the interaction between climate variability, i.e., rainfall distribution during the fallow period, and cover crop management should be considered to explain the impact of inter-annual variability on the water balance. Thus, destroying cover crops mechanically in late autumn and retaining the residues as mulch could be a good compromise between the multiple services the cover crop provides during the fallow period and avoiding the negative impact on soil water availability for the next cash crop.

Wheat, triticale and common bean are planted in both irrigated and rainfed conditions and may suffer the effects of water stress in both situations. The objective of this work was to evaluate the effect of water stress on the physical and chemical qualities of wheat (Triticum aestivum), triticale (Triticosecale wittmack) and common bean (Phaseolus vulgaris L.) grains. The experiment was conducted at the Embrapa Cerrados experimental station, in Planaltina, DF, Brazil. The experimental design was in randomized blocks with four replications. The treatments were composed of four water regimes (187 mm, 304 mm, 410 mm, 535 mm) applied to common bean (BRS Realce), two wheat genotypes (CPAC 0544 and BRS 404) and triticale (BRS Ulisses). The physical quality of grains was evaluated by the weight of a thousand grains (WTG) and color of the grains (represented by the luminosity (L*), chroma (C*) and hue angle (h*); the chemical quality was determined by protein, carbohydrate, lipid, ash, macro and microminerals contents. Water stress reduced grain yield of all species, however it did not reduce the weight of one thousand grains of the wheat genotype BRS 404, showing the potential of this cultivar, though it did lead to reduced WTG in common bean, triticale and the wheat genotype CPAC 0544. There was also a reduction of luminosity (L*) in the grains for both studied wheat genotypes, and chroma (C*) and hue angle (h*) for triticale. Water deficit also affected protein, carbohydrate, lipid and ash contents, with an increase in the protein content and a reduction in the carbohydrate and ash contents in common bean. In general, water stress reduced macro and micromineral contents in the grains, caused an undesirable change in the physical quality of the grains, and affected the chemical quality of the grains.

Drip irrigation has been gradually adopted for winter wheat production in the North China Plain (NCP) due to significant saving from using irrigation water and improving water and nitrogen use efficiencies. However, the optimal water and nitrogen application rates for drip-irrigated wheat are still unclear. A field experiment with five nitrogen application rates (0, 120, 180, 240, and 300 kg ha−1, referred as N0, N1, N2, N3, and N4) and three irrigation levels (40, 30, and 20 mm per irrigation, referred as I1, I2, and I3) was conducted during the 2015–2016 and 2016–2017 winter wheat seasons to study the effects of irrigation and nitrogen rates on crop growth, yield, and the water and nitrogen use efficiencies. Results showed that increasing irrigation and nitrogen application rates notably improved actual evapotranspiration, leaf area index, aboveground biomass, grain yield, and water use efficiency (WUE) of winter wheat. However, nitrogen application rates exceeding 240 kg ha−1 were not beneficial for wheat growth, grain yield, WUE, and irrigation water use efficiency (IWUE). The maximum grain yields of 8034 and 8760 kg ha−1 were achieved in N3I1, which had WUE of 2.08 and 2.23 kg m−3, and IWUE of 4.46 and 4.87 kg m−3 in 2015–2016 and 2016–2017, respectively. At the same time, N3I1 did not result in much reduction of nitrogen partial factor productivity (NPFP) (average of 34.99 kg kg−1 in N3I1 for two seasons). Considering comprehensively growth, yield, WUE, IWUE, and NPFP, combination of N rate of 240 kg ha−1 and irrigation quota of 40 mm per irrigation was optimal pattern for drip-irrigated winter wheat. These results may provide a scientific basis for water and nitrogen management of drip-irrigated winter wheat in the NCP.

The Ningxia Hui Autonomous Region (NX) in Northwest China has been challenged by water scarcity and drought for decades. In this study, to understand the spatio-temporal variation, cause analysis and relationship with atmospheric circulation of ET0 in Ningxia, ET0 and other climate factors at 20 national climate stations from 1957 to 2018 were analyzed. Results showed that ET0 in NX (Ningxia), NYR (Northern Yellow River Irrigation Area) and SMA (Southern Mountain Area) had increased significantly at annual scale, whilst the CAZ (Central Arid Zone) was the opposite trend, and ET0 had a trend of first rise and then decline from north to south in spatial distribution. ET0 was most sensitive to RH and Tmax at annual scale in Ningxia, while the greatest contribution rates were Tmax and SD. Ningxia was becoming drier in the past decades. The abrupt change in ET0 at approximately 1990, and it’s long and short period were 25a(15a) and 10a(5a) at annual scale, respectively. The four teleconnection indices could be used to predict changes in ET0 at annual and autumn scale, while the ENSO and PDO could predict changes in ET0 of summer and IOD and AO could predict changes in ET0 of spring and winter.

Drought is a major limiting factor for rainfed spring wheat production on the semiarid Loess Plateau of China. Suitable tillage practices are important for improving precipitation use efficiency (PUE), which is the ratio of grain yield to annual precipitation. To obtain a better understanding of the effects of conservation tillage practices on PUE on the semiarid Loess Plateau, PUE was divided into five steps: precipitation storage efficiency, farmland water consumption rate, ratio of transpiration to evapotranspiration, crop transpiration efficiency, and harvest index. Six tillage practices were assessed in this paper, including conventional tillage with no straw (T), no-till with straw cover (NTS), no-till with no straw (NT), conventional tillage with straw incorporated (TS), conventional tillage with plastic mulch (TP), and no-till with plastic mulch (NTP), based on a long-term experiment initiated in 2001. The impact of tillage practices on soil quality, soil water storage, soil evaporation, biomass yield, and grain yield of spring wheat were monitored in 2015 and 2016. The results show that NTS improved soil quality and soil water storage before sowing. No-till with plastic mulch and NTS increased evapotranspiration but decreased evaporation, thus optimizing precipitation storage efficiency, the farmland water consumption rate, the ratio of transpiration to evapotranspiration, and crop transpiration efficiency, which gave rise to greater aboveground dry matter accumulation and more dry matter accumulation in grain. As a result, grain yield under NTS and NTP was significantly increased by 45 and 41 % compare to T, respectively, with corresponding improvements in PUE of 43 and 39 %. Therefore, both NTS and NTP have potential to substantially increase grain yield of spring wheat and PUE. However, for sustainable intensification in the long-run, NTS is the best combination of tillage and soil surface management for spring wheat production on the semi-arid Loess Plateau of China.

The sustainability of spate-irrigated agriculture in a semi-arid climate depends on efficient use of irrigation water. Thus, efficient capture and storage of soil moisture in the field are crucial for sustained productivity. The main objective of this study is to examine the performance of improved field design strategies to manage variable irrigation water supply and application time in the Gash agricultural scheme (GAS) in eastern Sudan where open-end border irrigation is practiced to irrigate large fields with variable sizes that range from 250 to 1250 ha. Irrigation performance was examined using the WinSRFR model for a large-sized field (8400 m × 500 m), continuously irrigated for 25 days but also under alternative designs and irrigation times. The performance was evaluated using efficiency, adequacy and uniformity criteria. The results demonstrate that the current irrigation practices are quite inefficient but could be substantially improved by adopting alternative design and operational strategies. A vertical division of the field (8400 m × 250 m) under the average inflow condition could result in a substantial increase in application efficiency (from less than 50% to over 70%), distribution uniformity (from 0.34 to 0.87), and irrigation adequacy (from 0.68 to 1). Additionally, the fields could be irrigated in considerably less time when an alternate irrigation schedule between two equally divided fields is followed, which indicated time savings of 40 % under a high inflow rate scenario (occurring during a large flood season), and a 20% reduction in time under an average inflow rate scenario (occurring during a medium flood season). Therefore, this modelling study has demonstrated a great potential to significantly improve irrigation performance by applying alternative field designs and operation strategies in the GAS. The modelling outcomes confirmed that the farmers’ indigenous experiment, though without a scientific study, on the vertical division of a large-sized field is indeed successful in improving irrigation performance, and could be adopted in other similar conditions.

Water scarcity, climate variability and continuing growth in water demand have put severe pressure on high‐quality freshwater sources. This challenge exacts the necessity to explore alternative water sources for agricultural irrigation. The objective of this study was to implement the integrated geospatial Multi-Criteria Decision Analysis (MCDA) with the Analytical Hierarchy Process (AHP) to evaluate the potentiality of reclaimed water use for agricultural irrigation in California. Five evaluation criteria included in this study were agricultural land (crop type), climate conditions, water policies, irrigation status, and proximity to wastewater treatment plants (WWTPs) respectively. The suitability maps for reclaimed water use were generated for three cases in terms of accessibility to WWTPs, their discharge volume and appropriate treatment processes respectively. In addition, a composite suitability map was produced using the hybrid model considering all three cases together. Results from this study led to a better understanding of sustainable reclaimed water use for crop irrigation at a regional level. It provided supporting evidence of the applicability of the GIS-MCDA method integrated with AHP technique for a larger geographical scale with a diverse crop pattern. This study established the importance of using both knowledge-based and data-driven criteria and sub-criteria in the decision framework. The results also highlighted how the spatial distribution of suitable areas for reclaimed water reuse is closely linked to the agricultural areas.

Interreplicate variability—the spread in output values among units of the same sensor subjected to essentially the same condition—can be a major source of uncertainty in sensor data. To investigate the interreplicate variability among eight electromagnetic soil moisture sensors through a field study, eight units of TDR315, CS616, CS655, HydraProbe2, EC5, 5TE, and Teros12 were installed at a depth of 0.30 m within 3 m of each other, whereas three units of AquaSpy Vector Probe were installed within 3 m of each other. The magnitude of interreplicate variability in volumetric water content (θv) was generally similar between a static period near field capacity and a dynamic period of 85 consecutive days in the growing season. However, a wider range of variability was observed during the dynamic period primarily because interreplicate variability in θv increased sharply whenever infiltrated rainfall reached the sensor depth. Interreplicate variability for most sensors was thus smaller if comparing θv changes over several days that excluded this phenomenon than if comparing θv directly. Among the sensors that also reported temperature and/or apparent electrical conductivity, the sensors exhibiting the largest interreplicate variability in these outputs were characterized by units with consistently above or below average readings. Although manufacturers may continue to improve the technology in and the quality control of soil moisture sensors, users would still benefit from paying greater attention to interreplicate variability and adopting strategies to mitigate the consequences of interreplicate variability.

This study evaluated the effects of salicylic acid (SA), beeswax waste extract (BWE) and licorice extract (LE) as novel biostimulants, on drought-induced oxidative stress on sesame. The treatments consisted of three drought stress conditions (full irrigation, 90 % field capacity (FC); moderate stress, 60 % FC; and severe stress, 30 % FC) together with four exogenous foliar applications (control, water; LE, 5000 ppm; BWE, 2000 ppm; and SA, 1.5 mM). Plants subjected to drought stress displayed significant reduction in plant height, leaf area index, biological and seed yield, chlorophyll a and b content, quantum efficiency of photosystem II (Fv/Fm), net photosynthetic rate (Pn), stomatal conductance (gs), transpiration (Tr) and water use efficiency (WUE). Drought stress stimulated Malondialdehyde (MDA), proline, protein and carotenoid contents, and catalase (CAT), ascorbate peroxidase (APX), Guaiacol peroxidase (GPX) and glutathione reductase (GR) activity, while the exogenous foliar application of substances mitigated the oxidative damages. The alleviated effect of BWE on drought stress was more effective than those of LE and SA. In conclusion, it could be recommended that the application of the natural substances may lead to overcoming the negative effects of drought stress by regulating osmoprotectants content and antioxidant defense system, increasing mineral nutrients in plant organs and adjusting photosynthesis systems; consequently, contributing to improving the sesame productivity.

Determining methods for increasing irrigation water productivity is important for sustaining high wheat grain yields in the irrigated region of the Loess Plateau in China. Plastic-covered ridge and furrow planting has been widely applied in dryland farming, as it markedly increases precipitation productivity and crop yields. However, whether this planting system can significantly increase irrigation water productivity and whether it can reduce the irrigation volume for high-yielding wheat production in irrigated regions of the Loess Plateau are unclear. In the present study, plastic-covered ridge and furrow planting and traditional flatbed planting were performed at four irrigation levels. The objective was to investigate whether applying plastic-covered ridge and furrow planting to an irrigated farmland system could reduce the irrigation water requirements and increase water productivity for high-yielding wheat production. The results suggested that plastic-covered ridge and furrow planting significantly increased soil moisture content and increased both grain yield and water productivity of wheat. At the 0, 400, 1200, and 2000 m3 ha−1 irrigation levels, compared with that resulting from traditional flatbed planting, the grain yield resulting from plastic-covered ridge and furrow planting was 51.7 %, 64.8 %, 25.5 %, and 5.84 % greater, respectively. At the high-grain-yield level (6–7 t ha−1), the plastic-covered ridge and furrow planting system at 1200 m3 ha−1 irrigation conserved 40 % of irrigation water during wheat production. And it coordinated the relationships among grain yield, quality, water protuctivity and for wheat production. These findings show that the plastic-covered ridge and furrow planting system with 1200 m3 ha-1 irrigation is suitable for sustainable high-yielding wheat production in the irrigated regions of the Loess Plateau of China.

As the second carbon storage pool, soil is easily influenced by human activities. Mulched drip irrigation is a water-saving irrigation technique used widely in arid and semi-arid regions. However, information about the response of CO2 exchange to mulched drip irrigation, such as the wetter and warmer soil, is limited. To identify the carbon emissions effects of mulched drip irrigation, we carried out a field experiment using drip irrigation with and without clear plastic mulching during the cotton growing seasons of 2015 and 2016. We monitored the temporal and spatial variation of soil moisture, soil temperature, cotton growth stage, biomass, lint yield, CO2 emissions, and the relationship between soil respiration rate and soil climate. The results showed that plastic mulching drip irrigation increased soil moisture and soil temperature, especially during the early and middle growth stages of cotton. The soil respiration rate was related positively to the higher soil temperature and moisture conditions promoted by plastic film mulching, although the coefficients of determination were low (R2 were 0.480 and 0.205, corresponding p-value was both 0.000, respectively). The highest value of soil respiration was obtained within the narrow rows under the drip tape, regardless of the practice of mulching or not. The soil respiration rate under plastic mulch in the narrow and wide rows were on average 28.35 % and 22.48 % higher than non-mulched control. Meanwhile, the amount of total CO2 emissions was significantly increased by 25.34 % and 28.90 % in these same rows, respectively (p-values were 0.006 at narrow rows and 0.010 at wide rows in the first year, and 0.000 at same rows in the second year). The differences of CO2 emission in the bare soil was not significant between mulched plots and non-mulched control (p-values were 0.757 and 0.918 in the first and second growing seasons, respectively). In addition, plastic mulching significantly improved the biomass and yield of cotton, by 61.49 % and 12.83 % on average (p-values were 0.034 and 0.039 in 2015, 0.024 and 0.032 in 2016), respectively. The results indicate that the application of drip irrigation under plastic mulch could increase soil water content and temperature, promote cotton growth, and improve lint yield. However, it may also lead to increased CO2 emissions, which can intensify the warming of the climate.

The Granier thermal dissipation (TD) method is probably the most applied method to compute the transpiration flux of trees, due to its simplicity and effective compromise between theory and data availability. Starting from the heat transfer equations at the basis of Granier’s method, the objective of this paper is to derive an analytical solution for the transpiration flux to extend the sap flow equations to the radial domain. We adopted a flexible approach to cope with the differences in radial sapflow density (SFD) profile shapes that are known to occur in relation to wood anatomy (diffuse porous vs. ring- or non-porous xylem). With this purpose, we investigated the robustness of the equations developed on some experimental and reliable radial SFD measurements available in literature to test the influence of considering or not considering the active zone close to the cambium, where most of the species-specific differences are likely to be observed. Moreover, the parameters derived by the extended formulation, are interpreted as descriptive of species-specific radial sap flow patterns. The reliability of the suggested procedure was checked against several experimental SFD profiles from literature: i) monotonically increasing SFD from the centre of the stem towards the cambium, ii) increasing SFD from the centre of the stem and then constant SFD towards the cambium, and iii) increasing SFD from the centre of the stem to a maximum SFD and then decreasing towards the cambium. Results show that according to the suggested procedure, an increasing number of parameters depending on the SFD profile complexity are required to synthetically describe the transpiration flux of different tree species. For the simplest case of monotonically increasing SFD, which could be assumed as standard under conditions of a diffuse porous tree structure, only two parameters with a clear physical meaning are required.

Reclamation of saline-sodic soils for agricultural and vegetation ecological establishment is an important way to solve food and environmental problems, especially in developing countries. A water–salt regulation method using scheduled drip irrigation to control the soil matric potential (SMP) at a depth of 0.2 m immediately under drip emitters was proposed and the application effect of the method applied in field experiments was evaluated for reclamation of saline-sodic wasteland at five sites with different climates, land-use objectives, and planting patterns. A low-salinity environment was created in the whole soil profile, especially in the root zone, and the salt leaching process was divided into three stages: rapid desalination, slow desalination, and salt stabilization. The soil environment was improved with reclamation time, resulting in improved land productivity, crop yields at levels close to those in local farmland after 2–3 years, and good landscape vegetation ecosystems were created by establishment of artificial vegetation and natural germination of seeds in the soil seed bank. Soil alkalization should receive some attention during the salt leaching process because it may affect the growth of acid-loving plants. In addition, the low survival rates for salt-sensitive/non-salt tolerant landscape plants in the early reclamation period led to the creating a non-saline soil environment by adding non-saline soils into planting holes. Overall, the water–salt regulation method to control SMP immediately under scheduled drip irrigation emitters is suited for saline-sodic soils restoration, and some suggestions were proposed for its better application according to the field experiments.

Wastewater reuse in agriculture can be a viable option to solve future freshwater shortages but may need an additional treatment process (Stage-II) to become a safe option. As wastewater reuse interacts with many facets of coupled human and water systems, the introduction of Stage-II treatment systems in wastewater reuse in agriculture must be understood in terms of socio-hydrology. This paper builds on a place-based socio-hydrological model of a wastewater-reused watershed in South Korea and uses it to: (1) identify key parameters in human and water systems that have a significant impact on wastewater reuse in agriculture; (2) explore the impacts of changing agricultural environments by altering the key parameters; and (3) develop the possibility space of future changes from current decision-making. Key parameters concern the characteristics of urbanization, domestic water use, and greenhouse cultivation. Urbanization can reduce the demand for Stage-II irrigation within an urbanizing watershed by reducing irrigation areas and increasing water availability. Domestic water use has a large impact on the economics of indirect wastewater reuse. Greenhouse cultivation influences the demand for Stage-II irrigation, mainly by reducing water availability. Moreover, it could further affect the demand if the communities evolved to have a greater concern for the use of groundwater resources. The possibility space shows that wastewater reuse has a strong influence on groundwater and could relieve agricultural water deficits through the diversification of irrigation sources, and could be a more economical irrigation practice than groundwater irrigation under changing agricultural environments.

Direct root-zone irrigation is a novel subsurface drip irrigation strategy for water conservation. However, a comparison with traditional irrigation methods is lacking to better define the potential advantages of direct root-zone irrigation. A two-year study was conducted to evaluate the performance of Vitis vinifera L. cv. Cabernet Sauvignon under direct root-zone irrigation and surface drip irrigation in a commercial vineyard with loamy sand soil in a semi-arid region of southcentral Washington State, USA. Plant water status, root traits, grape yield, berry morphology and composition, and crop water use efficiency were compared between irrigation methods under three irrigation rates. Compared to surface drip irrigation, direct root-zone irrigation improved grape yield by 9–12% and crop water use efficiency by 9–11% under varied climate conditions with minor effects on berry composition, which could be potentially adjusted by irrigation rate. Moreover, grapevines irrigated through direct root-zone irrigation had 48–67% and 50–54% decrease in root number, respectively, at high and moderate irrigation rates in the upper soil profile (0–60 cm) with a decrease in water stress as revealed by higher midday stem water potential. Irrigation rate was the major factor influencing berry morphology. In fact, reduced irrigation resulted in a decrease in weight, size and number of berries. We conclude that direct root-zone irrigation could be a successful tool for improving yield and crop water use efficiency, potentially encouraging deep rooting to alleviate the water stress in grapevine under seasonal drought, and offering the ability to modify berry morphology and composition by adjusting the amount of water use.

Conceptualising wheat growth, yield and water productivity (WP) relationships with future climate change is necessary for sustainable agriculture and food security. This study assessed the climate change influences on wheat yield and WP with and without CO2 enrichment under semi-arid conditions. Statically bias-corrected climate change projections were coupled with AquaCrop model v5.0 to predict the wheat growth-span, yield and WP variations in Punjab, Pakistan. Acute wheat seasonal warming, characterised by sharp Tmin increase than Tmax, and substantial rainfall drops lead to short growth-spans and prompt ample yield reductions. However, CO2 enrichment promises to offset the negative wheat yield trends. Higher wheat yield vulnerability was detected for the late-season climate warming during the grain-filling stage. Wheat yield reduction and the limited influence of beneficial CO2-enrichment caused the future WP to decline consistently. CO2 enrichment featured a noteworthy mitigation role in sustaining and improving future wheat yield and WP. In conclusion, CO2 enrichment could impart some beneficial influences to wheat yield and WP, but would not fully eliminate the negative impacts of future climate warming under semi-arid conditions of Punjab, Pakistan. The reliability of such estimates demands a further in-depth examination of crop yield responses to carbon–temperature–water interactions under various field management conditions.

Field irrigation water management depends on interactions among crop yield, soil water/salt and groundwater/salt in arid irrigation area with shallow-saline groundwater. This paper presents a novel uncertainty simulation-optimization framework for irrigation water allocation and sustainable agricultural environment, which integrates simulation of physical processes of soil-groundwater water and salt balance into an uncertainty-based optimization model. The impacts of crop evapotranspiration, soil water and salt and groundwater levels are interactively involved in the simulation model. Uncertainties (economic and crop parameters, available water amount) presented as fuzzy boundary intervals and probability distribution functions are considered in the optimization model. This field irrigation water allocation framework emphasizes the role of field soil water and salt movement processes to decision-making of irrigation water allocation. Then, the proposed simulation-optimization framework was applied to a case study in the Hetao Irrigation District, an arid area of northwest China where soil salinity is a serious environmental problem induced by irrigation and shallow groundwater. Therefore, optimal irrigation water allocation solutions can be generated for providing decision makers with reliable decision options where the maximum system benefits resulting from sustainable agricultural production are desired. Furthermore, the results can support analysis of interrelationships among system benefits, water allocation planning and groundwater depth, soil salt content constraints. Scenario analysis (groundwater table depth (GTD) = 1, 1.5, 2, 2.5, 3 m and no groundwater exchange consideration) showed that the maximum net benefit could be [27469, 44818] Yuan with the groundwater table depth of 1.5 m. Also, the irrigation water allocation changed when the salt constraint was considered, which indicates that the results obtained by the developed framework can alleviate soil salinization to a certain degree. Therefore, this framework can provide more effective information for the irrigation water management and soil salinization control, which is meaningful for the sustainable development of irrigation agriculture.

Australia’s sophisticated and advanced water market legislation has allowed direct investment by non-landholder stakeholders in water ownership, which over time has increased the volume of water entitlements owned by government, non-governmental organisations and non-landholder investors (e.g. superannuation companies, trade speculators). The growing market value of Australian water entitlements, driven by increased water scarcity and international commodity prices, has meant that water is now one of the most valuable assets owned by many irrigators. However, to date, there is no standard practise of financial water valuation and accounting, nor is there an understanding of the most common methods used by various stakeholders. We report information from 63 in-depth expert interviews with bankers, environmental water holders, financial investors/agri-corporates, property evaluators and water brokers in the Murray-Darling Basin to establish the current practices employed. The most common valuation methods used current market prices based on water register and water broker data. Water entitlements were valued with historical cost or fair value water accounting, depending on the stakeholder. However, given the lack of standardised methodology, evaluator discretion and fast moving (or thin) markets can lead to considerable divergence in water valuation values. Recommendations are made for the need for greater transparency and standardised water valuation methods.

Canopy water interception is an important factor in water use efficiency analysis and sprinkler-based fertigation technique development. In the present study, alfalfa canopy water interception and its influence factors were assessed under low wind conditions. The canopy interception capacity for three growth stages of alfalfa (S1, early vegetative stage; S2, late vegetative stage; S3, bud stage) were measured under two types of low-pressure spray sprinklers. The dynamics of canopy interception and interception ratio with irrigation depth were also observed. The total irrigation depth for all measurements was around 8 mm. A weight-based canopy interception measurement device was installed outdoors and integrated with a 20-psi sprinkler at 1 m above the canopy. The alfalfa canopy interception first increased rapidly with irrigation depth, but then stabilized and reached canopy interception capacity (Im). The minimum irrigation depths to achieve the Im values were 2 mm, 3 mm, and 4 mm at the S1, S2 and S3 stages, respectively. Im increased significantly across growth stages, and ranged from 0.46 mm to 1.49 mm. Interception ratio decreased gradually as irrigation depth increased. With an approximately 8-mm total irrigation depth, interception ratio ranged from 5.27 % to 17.59 % over all growth stages. Water application rate had no effect on Im, and Im decreased with droplet diameter. Generally, Im was higher and reached more quickly with the R3000 sprinkler compared to the D3000 sprinkler. Fresh weight, plant height, and LAI of alfalfa had significant positive correlations with canopy interception capacity, and a quadratic regression model was developed with using plant height as a factor. This study provides valuable and basic information for irrigation schedules and fertigation in alfalfa cultivation.

Bangladesh is one of the most densely populated nations that nonetheless has largely achieved staple self-sufficiency. This development has been enabled in part by the rapid proliferation of small-scale irrigation pumps that enabled double rice cropping, as well as by a competitive market system in which farmers purchase water at affordable fee-for-service prices from private irrigation pump owners. Excess groundwater abstraction in areas of high shallow tube-well density and increased fuel costs for pumping have however called into question the sustainability of Bangladesh's groundwater irrigation economy. Cost-saving agronomic methods are called for, alongside aligned policies, markets, and farmers' incentives. The study assesses different institutions and water-pricing methods for irrigation services that have emerged in Bangladesh, each of which varies in their incentive structure for water conservation, and the level of economic risk involved for farmers and service providers. Using primary data collected from 139 irrigation service providers and 556 client-farmers, we empirically examine the structure of irrigation service types and associated market and institutional dimensions. Our findings demonstrate that competition among pump owners, social capital and personal relationships, and economic and agronomic risk perceptions of both pump owners and farmers significantly influence the structure of irrigation services and water pricing methods. Greater competition among pump owners increases the likelihood of pay-per-hour services and reduces the likelihood of crop harvest sharing arrangements. Based on these findings, we explore policy implications for enhancing irrigation services and irrigation sustainability in Bangladesh.

While the benefits of soil water management practices relative to soil erosion have been extensively documented, evidence regarding their effect on yields is inconclusive. Following a strong El-Niño, some regions of Ethiopia experienced major droughts during the 2015/16 agricultural season. Using the propensity scores method on a nationally representative survey in Ethiopia, this study investigates the effect of two widely adopted soil water management practices - terraces and contour bunds - on yields and assesses their potential to mitigate the effects of climate change. It is shown that at the national level, terraced plots have slightly lower yields than non-terraced plots. However, data support the hypothesis that terraced plots acted as a buffer against the 2015 Ethiopian drought, while contour bunds did not. This study provides evidence that terraces have the potential to help farmer deal with current climate risks. These results can inform the design of climate change adaptation policies and improve targeting of soil water management practices in Ethiopia.

The semi-arid region of the Loess Plateau is typical of rain-fed agricultural production in Northwestern China. In this area, the ridge mulched system (RM) is a widely-used measure to increase crop yield. The purpose of this study was to investigate the effect of RM on soil water and inorganic nitrogen (N) distribution, and grain yield of maize (Zea mays L.). The study was conducted over three consecutive years and consisted of four treatments (each replicated three times): i) RM with N application rate of 260 kg N ha-1 (RM-N260); ii) RM with 180 kg N ha-1 (RM-N180); iii) a traditional flat cultivation system without mulching (F) with 260 kg N ha-1 (F-N260); iv) F with 180 kg N ha-1 (F-N180). Mean soil water content during the maize growing season was increased by RM in 2013 only. However, RM increased the soil water storage significantly at the 3-leaf (V3) and 6-leaf stage (V6), and decreased evapotranspiration (ET) during pre-silking stage in all years. Compared to F, RM significantly improved maize grain yield by 79-123% in 2013, 23-25% in 2014, and 11-12% in 2015. Following three years of maize cultivation, soil inorganic N content increased substantially (two- to three-fold) in the RM system and 60% of the total inorganic N was accumulated in the top soil layers (0-60 cm) under the mulched ridge. Relative changes were much smaller in F, and most of inorganic N was stored in 0-20 cm and 100-160 cm soil layers. Generally, RM resulted in higher soil water storage during the pre-silking stage, which was the main reason for the improved maize grain yield. The nitrate leaching risk was reduced in RM-N180 compared with F, but nitrate leaching from the furrows between ridges was observed in RM-N260. However, the large increase in soil inorganic N content in RM-N180 after three years' cultivation indicates an oversupply of N and a potential risk of N losses to the environment over the longer term. Our study indicates, therefore, that RM is a suitable system for maize cropping in the semi-arid region of the Loess Plateau, with benefits in water and N use efficiency, but recommendations for appropriate N application rates are required to ensure long term agricultural sustainability, accounting for grain yields and environmental impacts. The mechanisms for inorganic N accumulation under the RM system are not fully understood and warrant further investigation.

In order to increase crop yield in semi-arid and arid areas, plastic film mulching (PFM) is widely used in Northwestern China. To date, many studies have addressed the effects of PFM on soil physical and biochemical properties in rain-fed agriculture in Northwestern China, but the findings of different studies are often contradictory. Therefore, a comprehensive review of the impacts of PFM on soil water content, soil nutrients and food production is needed. We compiled the results of 1278 observations to evaluate the overall effects of PFM on soil water content, the distribution of nitrate and soil organic carbon, and crop yield in rain-fed agriculture in Northwestern China. Our results showed that PFM increased soil moisture and nitrate concentration in topsoils (0-20 cm) by 12.9% and 28.2%, respectively, but slightly decreased (1.8%) soil organic carbon (SOC) content in the 0-10 cm soil layer. PFM significantly increased grain yields by 43.1%, with greatest effect in spring maize (79.4%). When related to cumulative precipitation during the crop growing season, yield increase from PFM was greatest (72.8%) at 200-300 mm, which was attributed to the large increase for spring maize and potato, implying that crop zoning would be beneficial for PFM in this region. When related to N application rate, crop yields benefited most from PFM (80.2%) at 200-300 kg/ha. A cost-benefit analysis indicated that PFM increased economic return by an average of 29.5%, with the best improvement for spring maize (71.1%) and no increase for spring wheat. In conclusion, PFM can significantly increase crop yield and economic return (especially for spring maize) in rain-fed agriculture areas of Northwestern China. Crop zoning is recommended for PFM to achieve the largest economic benefit. However, full account needs to be taken of the environmental impacts relating to N loss, SOC depletion and film pollution to evaluate the sustainability of PFM systems and further research is required to quantify and mitigate these impacts.

This study investigates multi-dimensional impacts of adopting new technology in agriculture at the farm/village and watershed scale in sub-Saharan Africa using the Integrated Decision Support System (IDSS). Application of IDSS as an integrated modeling tool helps solve complex issues in agricultural systems by simultaneously assessing production, environmental, economic, and nutritional consequences of adopting agricultural technologies for sustainable increases in food production and use of scarce natural resources. The IDSS approach was applied to the Amhara region of Ethiopia, where the scarcity of resources and agro-environmental consequences are critical to agricultural productivity of small farm, to analyze the impacts of alternative agricultural technology interventions. Results show significant improvements in family income and nutrition, achieved through the adoption of irrigation technologies, proper use of fertilizer, and improved seed varieties while preserving environmental indicators in terms of soil erosion and sediment loadings. These pilot studies demonstrate the usefulness of the IDSS approach as a tool that can be used to predict and evaluate the economic and environmental consequences of adopting new agricultural technologies that aim to improve the livelihoods of subsistence farmers.

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.