Highest Crop Water Productivity Research Articles

Exploring the Effects of Irrigation Schedules on Evapotranspiration Partitioning and Crop Water Productivity of Winter Wheat (Triticum aestivum L.) in North China Plain Using RZWQM2

ABSTRACTA significant basis for winter wheat production in China is the North China Plain (NCP). However, winter wheat production is severely hampered by water shortages in this area. Transpiration co‐occurs with photosynthesis, affecting crop water productivity (CWP). The purpose of this experiment is to use Root Zone Water Quality Model (RZWQM2) to study actual transpiration (AT) and evaporation (AE) under different irrigation schedules and then determine its impact on grain yield and CWP. In the 2019–2022 winter wheat growing seasons, four experimental treatments were set up: no irrigation during growth period (I0), irrigation at jointing stage (I1), irrigation at jointing and anthesis stage (I2) and irrigation at jointing, anthesis and filling stage (I3), and the RZWQM2 model was calibrated and verified in this experiment. A higher yield (7840.90 kg/ha for an average of 3 years) and the highest CWP can be obtained in I2 treatment (increased by 12.72%, 5.98% and 4.28% for an average of 3 years, respectively, compared to the other three treatments). The model has a good simulation effect on soil water dynamic change and plant physiological performance of the four treatments; the model showed that irrigation increased the simulated AE and AT; however, reduced AE/actual evapotranspiration. For the whole growth period, AT in I3, I2, I1 and I0 was 351.70, 317.30, 271.50 and 223.70 mm, respectively. Especially in the late growth stage of winter wheat, the AT in I3 was 65.20 mm for an average of 3 years, which was significantly higher than I2, I1 and I0 by 31.60, 13.50 and 10.00 mm, respectively. Thus, I3 increased AT at the late growth stage of winter wheat and resulted in an increase in grain yield; however, it did not significantly increase CWP. This study demonstrated that irrigation at winter wheat jointing and anthesis stages can improve the CWP to achieve the goal of stable grain yield and water saving.

Long-term potato response to different irrigation scheduling methods using saline water in an arid environment

Crops’ water requirement is generally higher than the annual average precipitation in arid environments characterized by scarce freshwater resources. While using saline water for irrigation can help sustain agriculture in water-stressed regions, several challenges arises concerning productivity and soil salinization. However, adoption of efficient irrigation techniques such as drip irrigation, irrigation scheduling, and deficit irrigation can help optimize water productivity and mitigate salinity problems in irrigated agriculture. In southern Tunisia, potato is considered among the main cultivated horticultural crops due to its high economic value while it is considered as a crop sensitive to salinity. This crop (cv. Spunta) was the subject of long-term studies (2002–2020) conducted during the fall period in the arid region of Médenine. The crop response to full and deficit irrigation with saline water was assessed for several seasons under contrasting climatic conditions. Scheduling using the soil water balance (SWB) method consisted of the total and/or partial replacement of accumulated crop evapotranspiration (ETc), as derived from climatic data and crop coefficients. The impact of decreasing amounts of irrigation waters on crop yield and soil salinity with waters having a salinity ranging between 3 and 7 dS m−1 was evaluated. Results showed improvements in yield (30% to 37%) obtained with the SWB strategy under actual farming conditions, supporting the use of this strategy for irrigation. Appropriate scheduling also seems to be a key element in saving water (15%–22%) and in reducing risks of soil salinization. In the dry environment of southern Tunisia, optimum supply seems to correspond to a replacement of 100% to approximately 70%–80% of ETc. Applying such irrigation levels resulted in a lower salinity buildup in the root zone and higher crop water productivity. Natural salt leaching seems to be more effective under a more humid soil profile. Yield decreases and soil salinity increases almost linearly (r2 = 0.60) with decreasing irrigation water amounts. Future work should focus on the integration of management practices when using saline water. Investigating the relationship and interaction between irrigation amounts, cultivar, fertilizer supply, and salt leaching will help in resolving productivity and environmental issues.

Evaluating optimized irrigation strategies on crop productivity and field water utilization under micro sprinkling irrigation in typical cropping systems of the Huang-Huai-Hai Plain

Inefficient traditional irrigation methods have negative consequences for agricultural production and the depletion of groundwater resources. This two-year field experiment aimed to evaluate optimized irrigation practices for irrigation efficiency (IE) and water utilization in winter wheat-maize (W-M) and winter wheat-soybean (W-S) annual rotation systems. Four micro-sprinkler-based irrigation strategies were implemented during the winter wheat season, specifically when the soil water content (SWC) of the 40 cm soil layer reached 40% of the field capacity (FC) after sowing. Including W4 (irrigated to SWC at 40 cm reached 60% FC), W6 (irrigated to SWC at 60 cm reached 80% FC), FI (farmer's practice, with irrigation amount of 150 mm per irrigation, the same timing as W6), and a rain-fed (RF) as a control. Summer seasons had no irrigation except for emergence. The WHCNS model simulated water consumption. The results indicated that IE decreased with increasing irrigation volumes, and the W-S system demonstrated higher IE than W-M. Both W4 and W6 achieved the desired wetting zones, while FI resulted in water leakage. Surface runoff was not affected by irrigation. Compared to the FI treatment under both cropping systems, W4 significantly reduced field water losses, particularly deep percolation, by 18.3–39.4%. W6 and FI led to elevated winter wheat transpiration rates, impacting crop yield. W4 had comparable yields to W6 and FI, but higher crop water productivity with average increases of 17.9% and 21.3% in W-M, and 24.6% and 31.4% in W-S, respectively. W4 also showed higher harvest indexes in both systems. The W-S system had more stable interannual yields, higher water-holding capacity, and water use efficiency than W-M. Although RF had great water-saving potential, its yield losses were enormous. These optimized precision irrigation strategies significantly reduce water consumption while achieving substantial yield increases, thereby providing vital support for sustainable agricultural development.

Quinoa growth and yield, soil water dynamics, root growth, and water use indicators in response to deficit irrigation and planting methods

To address the growing issue of scarce water in the arid and semi-arid areas, it is essential to investigate the potential of drought tolerant crops and implement promising farm management strategies to improve water productivity and yield production. Therefore, a split plot experiment to investigate how different irrigation levels (I-1:100% water requirement (WR), I-2:75%WR, and I-3: 50%WR) and planting methods (P-1: basin, P-2: on-ridge, and, P-3: in-furrow) interact and affect quinoa water use, yield, root growth, and water productivity in southern Iran over two growing seasons. The results showed high seasonal crop evapotranspiration (993–1030 mm) in I-1 as a result of the high advection ratio (α), which ranged from 1.02 to 1.46 from the early vegetative to the seed filling stages. The P-3 increased transpiration rate by 4.5% and 7.7%, and decreased soil evaporation by 17% and 29% compared to P-1 and P-2, respectively. Single (Kc) and dual (Kcb + Ke) crop coefficients varied between 0.41 and 1.38 over the two growing seasons. Grain yield in P-3 were 25%, 34%, and 44% higher compared to P-1 and P-2 under I-1, I-2 and I-3, respectively. The study revealed that nearly 67% and 80% of the total root dry matter was in the 0–30 cm and 0–60 cm of the soil profile in all experimental treatments, respectively. Regardless of irrigation treatment, root length density (RLD) and root mass density (RMD) were found to be 18.9% and 15.7% lower in P-1’s top 0–20 cm of the soil profile than those obtained in P-2 and P-3, respectively. Analyses showed that the increased root length in deeper soil layers contributed to higher soil water uptake, and consequently higher crop water productivity. In addition, root-to-shoot ratio increased as the amount of the applied irrigation water was decreased. Quinoa exhibited the highest acclimation to water stress in P-3 based on water stress sensitivity coefficients (λi) and yield response factor (Ky) values. Crop water productivity (WPC) and irrigation water productivity (WPI) for grain yield varied between 0.17 and 0.28 kg m−3. In conclusion, in terms of grain yield, shoot and root dry matter and water productivity, I-2 and P-3 (75% WR irrigation level and in-furrow planting method treatment) is recommended as the optimum water and planting management strategy for quinoa cultivation in the study area as a measure to address water scarcity and food sustainability. Still, to improve yield and irrigation water efficiency, the effect of soil management practices such as mulching and organic amendments on soil water retention and nutrient availability for quinoa should be investigated.

Integrated application of fertilization and reduced irrigation improved maize (Zea mays L.) yield, crop water productivity and nitrogen use efficiency in a semi-arid region

Water scarcity as well as soil degradation and environmental problems potentially caused by excessive application of chemical fertilizers are major challenges to agricultural production in semi-arid areas. It is crucial to explore a suitable and eco-friendly strategy to achieve sustainable production of maize with high crop water productivity and nitrogen use efficiency. Here, a two-year field experiment with three irrigation levels of W1 (220 mm), W2 (140 mm) and W3 (60 mm), and five fertilization types of no fertilizer (CK), chemical fertilizer (CF), bio-fertilizer combined with CF (CFB), organic fertilizer combined with 70% CF (CFO) and bio-fertilizer combined with CFO (CFOB) was conducted to investigate the effect on dry matter, N uptake and remobilization, grain yield, crop water productivity, nitrogen use efficiency and economic benefits of maize in 2021 and 2022. The results showed that the W2 and W3 decreased in the leaf area index, photosynthetic rate, dry matter accumulation, the maximum dry matter accumulation rate and actual crop evapotranspiration. Under W1 condition, the CFB improved the growth of maize, increased the dry matter and nitrogen accumulation and yield, with 8.1% and 7.4% higher than CF in 2021 and 2022, respectively. Under deficit irrigation (W2 and W3), CFOB significantly increased the leaf area index, photosynthetic rate, dry matter accumulation at later growth stage, in addition, CFOB increased the post-silking N uptake and the percentage in total N content, finally improved the grain yield with 23.8% and 22.8% under W2, 22.5% and 25.7% under W3 higher than that of the CF in 2021 and 2022, respectively. Irrigation and fertilizer showed a coupling effect on grain yield, crop water productivity, agronomy efficiency and nitrogen use efficiency. Overall, the CFOB under moderate deficit (W2) exhibited the highest water productivity, nitrogen use efficiency and economic benefits, as well as maintained the high yield, could be a promising approach to sustainable development of local maize.

Exploring deficit irrigation as a water conservation strategy: Insights from field experiments and model simulation

Deficit irrigation has emerged as a viable approach to increase agricultural water productivity. The objectives of this study were to 1) develop water conservation strategies by investigating responses of green bean (Phaseolus vulgaris) and sweet corn (Zea mays var. saccharata) to four irrigation treatments and 2) evaluate the performance of the Decision Support System for Agrotechnology Transfer (DSSAT) model in simulating growth and yield responses of green bean and sweet corn under four irrigation treatments. A field experiment was conducted using 32 experimental plots, established under a linear move sprinkler irrigation system equipped with variable rate irrigation (VRI) technology, at the Tropical Research and Education Center (TREC), Homestead for two cropping seasons between November and March in 2020–2021 and 2021–2022. The experiment involved four irrigation treatments: full irrigation (FI) (T4), and three levels of deficit irrigation, 75% FI (T3), 50% FI (T2), and 25% FI (T1) with four replications arranged in a completely randomized block design (RCBD) for each crop. The average soil moisture content of the full irrigation treatments was maintained above the management allowable depletion (MAD). Field data collection included various parameters of the crops including plant phenology, plant height, canopy width, fresh and dry biomass, and yield. Results confirmed that all three deficit irrigation treatments did not significantly affect the yield and yield components of the two crops during both seasons compared to the T4. This finding revealed that the highest crop water productivity was achieved from T1, 38.3 and 41.4 kg m−3 for green bean and 54 and 53 kg m−3 for sweet corn during the 2020–2021 and 2021–2022 seasons and up to 75% irrigation water saving could be achieved without affecting plant growth and yield. The DSSAT model performed well in simulating yield and yield components for the two crops in response to the four irrigation treatments. Model evaluation results showed that the minimum mean absolute error (MAE) for green bean fresh pod yield simulation was 2.1 Mg ha−1 with an index of agreement (d-Stat) of 0.6, while for biomass, it was 0.24 Mg ha−1 with a d-Stat of 1. Similarly, for sweet corn, the model simulated fresh cob yield with a minimum MAE of 6.51 Mg ha−1 and d-Stat of 0.9 and biomass with MAE of 1.63 Mg ha−1 and d-Stat of 0.9. Overall, implementing deficit irrigation in green bean and sweet corn fields could result in considerable water savings while achieving acceptable crop yield. The DSSAT model could be also a useful tool to simulate green bean and sweet corn responses to different irrigation scenarios and aid water management decisions under South Florida conditions.

Irrigation Management Strategies to Increase Crop-Water Productivity and Grain Quality of Direct Seeded Rice in North West IGP: A Review

Due to its great productivity and profitability, rice (Oryza sativa L.) is farmed in alluvial irrigated tracts of northwest India. For half of the world's population as well as in our country, rice serves as the main source of calories. However, excessive groundwater use in rice farming has resulted in an alarming decline in water table, indicating overuse of groundwater. Therefore, it is necessary to investigate alternative, resource-conserving methods that can sustain rice production. Direct seeded rice presents a compelling option when the future of rice production is in jeopardy due to worldwide water constraint and rising labour costs. The oldest method of crop establishment in this regard, direct seeded rice (DSR), is becoming more and more well-liked constraints minimal input requirements. It has certain benefits, including labour savings, a reduction in water and manpower requirements, early crop maturity, cheap production costs, improved soil physical conditions for crops, a reduction in methane emissions, and greater options for being the best match in various cropping systems. For dry-seeded rice, management strategies that cut irrigation water use and boost crop-water production are needed. Some of the interventions in this respect include cultivars with short growing seasons, tillage, and irrigation scheduling. High crop-water productivity is ensured with optimal yields thanks to irrigation scheduling that aims to eliminate over- or under-irrigation. Tillage changes the edaphic environment of the soil, which impacts crop development. Because of their shallow root systems, rice plants are unable to use the water in the deeper layers of the soil. In order to increase the deep root growth of rice cultivars, deep tillage has become the preferable method. The present research evaluates irrigation management options to raise crop-water productivity and grain quality of DSR in northwest IGP based on the available evidence.

Regulated Deficit Irrigation during Vegetative Growth Enhances Crop Water Productivity in Chickpea (Cicer arietinum L.)

To optimize irrigation, agronomists need to modulate crop water productivity (CWP) throughout phenology. We compared regulated deficit irrigation (RDI) and sustained deficit irrigation (SDI) in chickpea (Cicer arietinum L. var. Blanoro), expecting RDI during vegetative growth (VG) to enhance CWP, as opposed to flowering (F) and pod-filling (PF) stages. The effects of RDI and SDI on grain yield, plant height, weight, grain caliber, pods and grains per plant, harvest index, and CWP, were tested through a complete randomized block experiment during the years 2020 and 2021, comparing full irrigation (FI, ETc = 100%), SDI (SDI75, ETc = 75% during all stages), and six RDI treatments varying in ETc% across phenology: VG50, VG75, F50, F75, PF50, and PF75. VG75 had higher CWP while minimizing impacts on productivity. During 2020, the plants were taller (0.44 ± 4.4 m), and increased in harvest index (0.47 ± 0.06), and CWP (0.90 ± 0.2 kg m−3) (p < 0.05), while in 2021, plants were heavier (11.4 ± 2.8 g) and increased in caliber (46.1 ± 3.0 grains); grain yield did not differ between the years (p ˃ 0.05), reaching 861.8 (2020) and 944.7 kg ha−1 (2021). Our results highlight the relevance of maintaining 100% ETc during flowering, and the maintenance of RDI at 75% ETc during vegetative growth.

Yield, water productivity and economic return of deficit-drip-irrigated tomatoes in Kaduna (Nigeria)

Compared to gravity flow systems, pressurized drip irrigation provides more efficient control of the amount of water applied, better irrigation uniformity, and a higher initial capital and operation costs. Hence, an economic analysis is required to determine its profitability over a projected time period. Field experiments were conducted in Afaka (Kaduna, Nigeria), during two dry seasons of 2018 and 2019 to determine the effect of regulated deficit irrigation on the yield, crop water productivity, and projected economic returns of UC 82B tomatoes under pressurized drip irrigation. The economic returns were evaluated using the benefit-cost ratio, net present values, and payback period analyses. The highest fresh fruit yield (19.0 t/ha) was obtained in the full irrigation treatment (T1), while the highest crop water productivity (4.94 kg/m3) was obtained in the deficit treatment with full irrigation at the vegetative and flowering stages followed by 60% of reference evapotranspiration at maturity (T7). The project was found to be profitable over the projected years, with benefit-cost ratios of 1.90 and 1.69; payback periods of 2.7 and 3.2 years for T1 and T7, respectively. The full irrigation of tomatoes was therefore found to be more economical than deficit irrigation in the area, with water not being considered as a limiting factor in terms of costs. Gravity drip irrigation was recommended to reduce the pumping cost of irrigation and thereby increase the profit margin.

Maize response to irrigation and nitrogen under center pivot, subsurface drip and furrow irrigation: Water productivity, basal evapotranspiration and yield response factors

Information and data about quantification and comparison of crop water productivity indices for various irrigation levels and methods and nitrogen (N) application timings “simultaneously” under the same conditions do not exist. Unprecedented and extensive field experiments were conducted for maize (Zea mays L.) in 2016 and 2017 under center pivot (CP), subsurface drip irrigation (SDI) and furrow irrigation (FI) methods with full irrigation treatment (FIT), 80 % FIT, 60 % FIT and rainfed treatment (RFT) with three N application timings. N treatments were: (i) traditional (TN), (ii) non-traditional-1 (NT-1) and (iii) non-traditional-2 (NT-2). Irrigation-yield production functions (IYPF); evapotranspiration-yield production functions (ETYPF), basal evapotranspiration (ETb), crop water productivity (CWP), irrigation water use efficiency (IWUE); evapotranspiration water use efficiency (ETWUE) and yield response factors (Ky) were quantified for each treatment and irrigation method. SDI method required the least seasonal irrigation amount in achieving maximum yield, followed by CP (>~30 mm more than SDI) and FI (>~55 mm more than SDI). Average crop water requirement for achieving maximum grain yield varied among the N treatments within and between the irrigation methods. Irrigation amounts for achieving maximum yields were about 160, 175 and 175 mm in TN, NT-1 and NT-2 nitrogen treatments, respectively, in the CP method; 130, 150 and 150 mm in TN, NT-1 and NT-2 nitrogen treatments, respectively, in the SDI method; and 184 mm in TN management in the FI method. The highest grain yield production per 25.4 mm of applied irrigation followed the order of CP-TN (2.07 Mg ha−1)>SDI-NT-2 (1.91 Mg ha−1)>FI-TN (1.22 Mg ha−1). Across all treatments for the given irrigation method, the highest averaged CWP of 3.00 kg m−3 (slope = 0.067 kg m−3) was observed in the SDI method (p < 0.05) followed by 2.84 kg m−3 (slope = 0.052 kg m−3) in the CP method (p < 0.05) and 2.51 kg m−3 (slope = 0.046 kg m−3) in the FI method. The lowest ETb was observed in FI-TN (169 mm), followed by CP-NT-2 (172 mm) and SDI-TN (255 mm). For two consecutive years, N treatments did not have significant (p > 0.05) influence on IWUE in the CP or SDI methods. The highest IWUE, CWP and ETWUE were always obtained with limited irrigation treatments (60 % FIT and/or 80 % FIT) whereas the lowest with FIT. Maize under limited irrigation management had Ky < 1 with CP, SDI and FI along with lower Ky values than the respective TN treatment in CP and SDI, suggesting that the yield reduction is impacted to a lesser degree from the magnitude of water stress. The overall conclusion disclosed that utilizing the combination of limited irrigation (80 % FIT) with NT-1 fertigation under SDI and CP, while 80 % FIT under FI can be viable management practices for achieving high grain yield and CWP in conditions similar to those presented in this research.

Effect of gravity-fed drip irrigation and nitrogen management on flowering quality, yield, water and nutrient dynamics of gladiolus in an Indian inceptisol

Gladiolus is a promising flower crop during winter season and its popularity is growing fast due to its higher price in the market. However, the productivity and quality of the crop in resource-scarce region are constrained by improper irrigation and nitrogen management practices. Based on this presumption, the current study has been developed with the precise objectives of examining the effect of gravity-fed drip irrigation scheduling coupled with integrated nitrogen management on growth, yield, water productivity and macronutrients distribution in soil and plant system of gladiolus. The field experiment accommodating four irrigation levels (surface irrigation I1, and gravity drip irrigation at 1.0, 0.8 and 0.6 (I2, I3 and I4) of pan evaporation replenishment) and three levels of nitrogen management (100% recommended dose of nitrogen (RDN) as vermicompost, 50% RDN as vermicompost + 50% RDN as fertilizer and 100% RDN as fertilizer, respectively N1, N2 and N3) was conducted during three consecutive rabi seasons on gladiolus. I2N2 furnished highest spike/plot (72.9), florets/spike (10.6), longest spike length (66.7 cm), greatest spike weight (43.0 g) and maximum spike yield (10458 kg ha−1) which were at par with I2N2. Highest crop water productivity (CWP) of 9.06 kg m−3 was accomplished in I4N2 followed by I3N2 (8.84 kg m−3). Drip irrigation, on average, could save water by 20.6% for I2, 36.6% for I3 and 52.4% for I4 and improve CWP by 50.2% for I2, 65.2% for I3 and 65.2% for I4 as compared with I1. Two predictive models were developed based on flower yield vs. I and ETa. Ky for total growing season was estimated at 0.66 (R2= 0.91). Maximum soil water storage was accumulated in the surface layer and well distributed down the layers underneath in drip irrigation system, while the reverse trend was noticed in the surface irrigation. Higher availability of soil N and leaf N concentrations were obtained with I2N2 and I3N2 and lower with I1N1. Based on maximum spike yield, water productivity, substantial water saving and N economy, I2N2 and I3N2 emerged superior for the selected inceptisol.

Mitigation of arsenic in broccoli through consumptive use of ground water and pond water as sources for irrigation

ABSTRACT Arsenic (As) contamination in ground water is raising concerns due to indiscriminate irrigation for a large variety of crops. Therefore, it is a challenge to reduce As uptake in relation to safe human consumption either by reducing water supply or by improving water quality without major yield losses. The experiment was laid out in Randomized Block Design (RBD) replicated four times with five water management treatments viz. T1 = 100% shallow tube well (STW), T2 = 25% STW + 75% pond water (PW), T3 = 75% STW + 25% PW, T4 = 50% STW + 50% PW andT5 = 100% PW with broccoli (cv. Green Magic) as a test crop in an As-affected village of Ghetugachi, West Bengal, India. Plant and soil samples were collected during harvesting. The calculated hazard quotient (HQ) suggests that despite having higher yield, As content in broccoli under T1 is unfit for human consumption. T2 having a low HQ (0.564) and moderate crop water productivity (CWP) and irrigation water productivity (IWP) values (5.46 and 8.07, respectively) is marked as safest. T4 with moderately high HQ (0.776) and fairly high CWP and IWP (5.62 and 8.31, respectively) can be considered for areas having relatively less contamination.

Optimizing irrigation amount and potassium rate to simultaneously improve tuber yield, water productivity and plant potassium accumulation of drip-fertigated potato in northwest China

High crop water productivity (WPc) and fertilizer use efficiency are the key to ensuring the sustainable development of agriculture in water-deficient areas, such as the northwest China. In order to determine the irrigation amount and potassium rate for optimizing potato yield, plant potassium accumulation and WPc of drip-irrigated potato, a two-year field experiment was conducted on the Loess Plateau of northwest China, with three irrigation levels (W1: 60% ETc, W2: 80% ETc and W3: 100% ETc, where ETc is the crop evapotranspiration) and four potassium levels (K0: kg ha−1, K1: 135 kg ha−1, K2: 270 kg ha−1 and K3: 405 kg ha−1). The results showed that leaf area index, chlorophyll content, aboveground dry matter, tuber yield, starch, vitamin C content and WPc generally increased with the increase of irrigation amount, while they first increased and then decreased with the increasing potassium rate. The trends of reducing sugar and potassium use efficiency were contrary to the above trends. The residue of available potassium in the soil increased with the increase of potassium rate, but decreased with the increase of irrigation amount. Irrigation amount and potassium rate had interaction effects on chlorophyll content, dry matter, tuber yield, reducing sugar, plant potassium accumulation and potassium use efficiency. To ensure high-yield, high-quality, water-saving and fertilizer-saving potato production, a water input (irrigation plus effective rainfall) range of 498–520 mm combined with a potassium rate range of 201–393 kg ha−1 was recommended. These results can provide a theoretical basis for the rational application of irrigation water and potassium fertilizer to improve tuber yield, quality and soil environment of drip-irrigated potato in northwest China.

Crop water productivity of cash crops under drip irrigation combined with soil mulching

Drip irrigation is one of important technique of watering especially during unstable and uneven distributed rainfall due to global climate change. It minimizes water loss hence may increase the CWP (Crop Water Productivity). The purpose of this study was to evaluate the drip irrigation combined with soil mulching to CWP of cash crops. This research was conducted from October 2020 to February 2021 at Jumantono, Karanganyar Regency, Indonesia. The experiment was arranged in the Strip Plot design with 3 factors, namely type of irrigation (drip and conventional) as main plot; mulch (control, silver black mulch, and straw mulch) also commodities (paddy and chili) as the sub-plot with 3 replications. Parameters observed were biomass and Crop Water Productivity (CWP). The results showed drip irrigation combined with soil mulching resulted in higher CWP at both chili and paddy.

Evaluating optimal irrigation for potential yield and economic performance of major crops in southwestern Kansas

The Decision Support System for Agrotechnology Transfer – Cropping System Model was used with an objective to evaluate maize (Zea mays L.), winter wheat (Triticum aestivum L.) and grain sorghum (Sorghum bicolor L. Moench) yield, crop water productivity (CWP) and return after variable cost (RAVC) under different combinations of irrigation interval/capacity and plant available soil water (PASW) thresholds on three soil types in southwestern Kansas. Maize, grain sorghum and winter wheat yields were maximized under irrigation capacity of 4.2–6.3, 3.1–4.2 and 2.5–3.1 mm/d, respectively. The lowest and highest values in the range corresponded to silt loam and fine sand soils, respectively. For maize, maximum RAVC ($630–710/ha) and CWP (25–27 kg/ha/mm) were achieved with a relatively shorter irrigation interval (25 mm/4–8 d). RAVC values for grain sorghum and winter wheat were not substantially affected by irrigation interval. The RAVC for grain sorghum and winter wheat ranged from $150 to $200/ha and $310 to $370/ha, respectively. The CWP of grain sorghum peaked at shorter irrigation interval (25 mm/6–8 d), whereas, high CWP of wheat was simulated even at longer irrigation interval (25 mm/26 d). Overall, for winter wheat and grain sorghum, irrigation strategy for attaining higher RAVC values is different from irrigation strategy for attaining higher yield. Whereas, for maize, irrigation strategy for higher yield is the same as that irrigation strategy for higher RAVC. This study guides producers to identify and prioritize the most suitable irrigation strategy for optimizing yield, CWP and/or income while enhancing sustainability of environment and management of ground water. The present work assumes all factors except water are optimal and findings are sensitive to dynamics of price changes, productivity levels and variations in crop management and climate.

Mandarin irrigation scheduling by means of frequency domain reflectometry soil moisture monitoring

The accurate estimation of plant water needs is the first step for achieving high crop water productivity. The main objective of the work was to develop an irrigation scheduling procedure for mandarin orchards under Mediterranean conditions based on replacing the amount of consumed water using reference values of soil moisture according to different phenological periods. The proposed methodology includes a definition part where the threshold values were established relating the trees’ stem water potential and the volumetric soil water content measured with Frequency Domain Reflectometry probes. A second part includes the steps for standardizing measurements from capacitance probes by using the LEACHM hydrological simulation model to take into account the sensor-to-sensor variations. Finally, an extrapolation procedure based on soil water retention curves was used for adapting critical soil water content thresholds to different soil conditions. Field evaluations were made in a citrus orchard located in eastern Spain during two seasons. Standardize critical soil water contents were: i) 24 % vol. for post-harvest, bloom - fruit set and phase III of fruit growth; ii) 27 % vol. for phase I of fruit growth, and iii) 29 % vol. for phase II of fruit growth with average daily air vapour pressure deficit values ranging between 0.2 - 0.4; 0.9–1.1 and 1.1–1.3 kPa, respectively. When implemented in the orchard, the sensor-based strategy resulted in water saving of 26 % respect to a control treatment, irrigated using the standard FAO-56 approach, without significant differences in yield and increasing the crop water productivity by 33 %. In conclusion, we suggest that the determination and use of the critical soil water content is a useful tool for scheduling irrigation. The proposed standardization and extrapolation methodology allows the irrigation strategy to be applied to other mandarin orchards under similar climatic conditions.

Optimization of drip irrigation and fertilization regimes for high grain yield, crop water productivity and economic benefits of spring maize in Northwest China

Spring maize is one of the major cereal crops in the arid and semi-arid regions of Northwest China, but limited water resources and low water/fertilizer use efficiency largely restrict the sustainable development of local agriculture. A two-year field experiment was conducted to explore the effects of water/fertilizer interaction on aboveground biomass, grain yield, crop water productivity (CWP), partial factor productivity (PFP) and economic benefits of spring maize. Particularly, the optimized combination of drip irrigation and fertilization regimes for high grain yield, CWP and economic benefits were attained by multiple regression analysis and likelihood estimation. The irrigation levels included I60 (60 % ETc, ETc is the crop evapotranspiration), I75, I90 and I105 in 2015, and I60, I80, I100 and I120 in 2016; the N-P2O5-K2O fertilization levels (kg ha−1) consisted of F60 (60-30-30), F120 (120-60-60), F180 (180-90-90) and F240 (240-120-120), corresponding to low, medium, medium high and normal high fertilization rates, respectively. Aboveground biomass, grain yield, CWP, PFP and net returns generally increased as irrigation and fertilization amount increased, except for that CWP and PFP constantly decreased with increasing irrigation and fertilizer amounts, respectively. There were significant interaction effects on these indexes in both years. The highest yields were 18.81 Mg ha-1 at I105F180 and 20.53 Mg ha-1 at I100F180, the highest CWP were 3.32 kg m-3 at I90F180 and 3.99 kg m-3 at I100F180, and the highest net returns were 17,482 CNY ha-1 at I105F180 and 20,174 CNY ha−1 at I100F180 in 2015 and 2016, respectively. Maize yield, CWP and net returns reached ≥95 % of their maximum values simultaneously when irrigation amount ranged 93 %∼126 % ETc and fertilizer (N-P2O5-K2O) amount ranged 124-62-62∼228-114−114 kg ha-1. The overall benefits of maize yield, CWP and net returns were finally maximized with irrigation amount of 109 % ETc (474 mm) and medium high fertilizer (N-P2O5-K2O) amount of 184-92−92 kg ha−1. This study can provide a guideline for appropriate water and fertilizer management for sustainable spring maize production in the (semi-)arid region of Northwest China.

The effect of regulated deficit irrigation (RDI) on advance vegetative phase to the water stress and water productivity of Soybean (Glycine max [L.] Merr.) plant

The objective of this research was to investigate the effect of regulated deficit irrigation on advance vegetative phase to the water productivity of Soybean. This research was conducted under plastic house on the field laboratory of Lampung University from October 2018 to January 2019. The water stress treatments in regulated deficit irrigation levels were DI1 (0 – 100 %) of total available water as a control, DI2 (0 – 80 %), DI3 (0 – 60 %), DI4 (0 – 40 %) and DI5 (0 – 20 %) of total available water (TAW) arranged in a randomized block design with four replications. The results showed that the soybean plant started to experience stress from week IV, the soybean plant started to experience stress within 0-40 % of total available water and continuing to stress until the end of growth, even the RDI treatment was stop at week VI. It means that the soybean plant which experience to tress at vegetative advance can’t be recovered even the soybean plant was irrigated to bring back the water to the field capacity. The (p) value was 0.6 and the Ks value were 0.84; 0.70; 0.68; 0.80, 0.86 and 0.88 at week IV, V, VI, VII, VIII and IX, respectively. The average Ks value was 0.79. There was no significant different between DI1 DI2, and DI3 in water productivity of soybean plant. The value of water productivity were 0.65, 0.49, 0.48, 0.40 and 0.42 at DI1, DI2, DI3, DI4, DI5, respectively. The optimum water management which the high crop water productivity (WP=0.48) was reach by RDI at DI3 treatment which maintain the available water between 0-60 % or the soybean plant must be irrigate by bring back the water to the 60 % of total available water. The optimum yield of soybean (Anjasmoro veriety) was 17.9 g/pot and crop water requirement was 36746.5 ml or equal to 566.08 mm.

A meta-analysis of global crop water productivity of three leading world crops (wheat, corn, and rice) in the irrigated areas over three decades

ABSTRACT The overarching goal of this study was to perform a comprehensive meta-analysis of irrigated agricultural Crop Water Productivity (CWP) of the world’s three leading crops: wheat, corn, and rice based on three decades of remote sensing and non-remote sensing-based studies. Overall, CWP data from 148 crop growing study sites (60 wheat, 43 corn, and 45 rice) spread across the world were gathered from published articles spanning 31 different countries. There was overwhelming evidence of a significant increase in CWP with an increase in latitude for predominately northern hemisphere datasets. For example, corn grown in latitude 40–50° had much higher mean CWP (2.45 kg/m³) compared to mean CWP of corn grown in other latitudes such as 30–40° (1.67 kg/m³) or 20–30° (0.94 kg/m³). The same trend existed for wheat and rice as well. For soils, none of the CWP values, for any of the three crops, were statistically different. However, mean CWP in higher latitudes for the same soil was significantly higher than the mean CWP for the same soil in lower latitudes. This applied for all three crops studied. For wheat, the global CWP categories were low (≤0.75 kg/m³), medium (>0.75 to <1.10 kg/m³), and high CWP (≥1.10 kg/m³). For corn the global CWP categories were low (≤1.25 kg/m³), medium (>1.25 to ≤1.75 kg/m³), and high (>1.75 kg/m³). For rice the global CWP categories were low (≤0.70 kg/m³), medium (>0.70 to ≤1.25 kg/m³), and high (>1.25 kg/m³). USA and China are the only two countries that have consistently high CWP for wheat, corn, and rice. Australia and India have medium CWP for wheat and rice. India’s corn, however, has low CWP. Egypt, Turkey, Netherlands, Mexico, and Israel have high CWP for wheat. Romania, Argentina, and Hungary have high CWP for corn, and Philippines has high CWP for rice. All other countries have either low or medium CWP for all three crops. Based on data in this study, the highest consumers of water for crop production also have the most potential for water savings. These countries are USA, India, and China for wheat; USA, China, and Brazil for corn; India, China, and Pakistan for rice. For example, even just a 10% increase in CWP of wheat grown in India can save 6974 billion liters of water. This is equivalent to creating 6974 lakes each of 100 m³ in volume that leads to many benefits such as acting as ‘water banks’ for lean season, recreation, and numerous ecological services. This study establishes the volume of water that can be saved for each crop in each country when there is an increase in CWP by 10%, 20%, and 30%.

Interactive Effects of Water and Fertilizer on Yield, Soil Water and Nitrate Dynamics of Young Apple Tree in Semiarid Region of Northwest China

Exploring the interactive effect of water and fertilizer on yield, soil water and nitrate dynamics of young apple tree is of great importance to improve the management of irrigation and fertilization in the apple-growing region of semiarid northwest China. A two-year pot experiment was conducted in a mobile rainproof shelter of the water-saving irrigation experimental station in Northwest A&amp;F University, and the investigation evaluated the response of soil water and fertilizer migration, crop water productivity (CWP), irrigation water use efficiency (IWUE), partial factor productivity (PFP) of young apple tree to different water and fertilizer regimes (four levels of soil water: 75%–85%, 65%–75%, 55%–65% and 45%–55% of field capacity, designated W1, W2, W3 and W4, respectively; three levels of N-P2O5-K2O fertilizer, 30-30-10, 20-20-10 and 10-10-10 g plant−1, designated F1, F2 and F3, respectively). Results showed that F1W1, F2W1 and F3W1 had the highest average soil water content at 0~90 cm compared with the other treatments. When fertilizer level was fixed, the average soil water content was gradually increased with increasing irrigation amount. For W1, W2, W3 and W4, high levels of water content were mainly distributed at 50~80 cm, 40~70 cm, 30~50 cm and 10~30 cm, respectively. There was no significant difference in soil water content at all fertilizer treatments. However, F1 and F2 significantly increased soil nitrate-N content by 146.3%~246.4% and 75.3%~151.5% compared with F3. The highest yield appeared at F1W1 treatment, but there was little difference between F1W1 and F2W2 treatment. F2W2 treatment decreased yield by 7.5%, but increased IWUE by 11.2% compared with F1W1 treatment. Meanwhile, the highest CWP appeared at F2W2 treatment in the two years. Thus, F2W2 treatment (soil moisture was controlled in 65–75% of field capacity, N-P2O5-K2O were controlled at 20-20-10 g·tree−1) reached the best water and fertilizer coupling mode and it was the optimum combinations of water and fertilizer saving.