Amount Of Irrigation Water Research Articles

Uncertain multi‐objective programming approach for planning supplementary irrigation areas in rainfed agricultural regions

AbstractRainfed agriculture is crucial for ensuring global food and water security, and supplementary irrigation is an effective means of improving the economic benefits in rainfed agricultural regions. This study proposes a novel uncertain optimization approach to optimize supplementary irrigation areas in rainfed agricultural regions. The approach incorporates multi‐objective linear programming, interval linear programming, fuzzy goal programming and stochastic expected value programming. In the proposed interval multi‐fuzzy goal stochastic expected‐value programming, uncertainties are expressed in the form of discrete intervals, probability distributions and fuzzy goals. This approach, which considers the randomness of precipitation during the optimization process and allocates limited irrigation water resources to different subareas and crops, was applied to a case study of crop irrigation area planning in Guyuan City, Ningxia Hui Autonomous Region, northwestern China. The maximum economic benefits and the minimum sum of the Gini coefficients among the different subareas and crops were regarded as the planning objectives, and a series of optimal irrigation areas with different crops and subareas under different water levels were obtained. The optimization results revealed that vegetables and fruits consumed large amounts of irrigation water to increase their economic benefits. In addition, allocating a large amount of irrigation water to wheat is essential to decrease the Gini coefficient and meet food security constraints, particularly at extremely low water levels. Compared with current management, the optimized irrigation area decreased by 30%, the crop water deficit index increased by 9%, the economic benefits increased by 3% and the total Gini coefficient of crops decreased by 17%, indicating that the optimization approach could fairly and reasonably allocate irrigation water resources. Our research provides a mathematical approach for decision‐makers to plan supplementary irrigation areas in rainfed agricultural regions.

Performance Indicators for Improving Irrigation Management in Aegean District

Water is vital for agriculture and its effective use has become imperative. The largest share of freshwater use in the world is in the agricultural sector with a rate of approximately 70%. Therefore, the evaluation of irrigation schemes is of great importance. In Turkiye, irrigation schemes are managed and distributed by organizations such as water user associations, municipalities, and irrigation cooperatives. In Türkiye, irrigation schemes with an service area of 500 ha or more are managed by water user associations. In this study, Ahmetli, Salihli and Menemen water user associations’ irrigation schemes, where the Gediz River is used as a water source, were chosen as materials. The selected irrigation schemes service area constitutes 60% of the total service area in the region (DSI (General Directorate of State Hydraulic Works) 2nd Region(Aegean region)). The service area of Ahmetli irrigation scheme is 50,532 ha, 22,797 ha in Salihli and 22,865 ha in Menemen. The main crop pattern of the irrigation area is vineyards, corn and cotton. These irrigation schemes were evaluated using performance indicators such as water supply, irrigation rate, and amount of irrigation water used per unit area. The raw data sets obtained from DSI cover the years 2007 and 2021. As a result, when looking at the average performance, relative water supply, irrigation rate and amount of irrigation water used per unit area were found to be 0.70, 57.99 and 7682.45 m3 ha-1, respectively. Although 70% of the irrigation water need can be met with the water diversion to the system, the irrigation ratio was approximately 58% indicating the problems in transferring water to the system and the irrigation techniques used by farmers on the field are not modern. In addition, the main reasons for the unirrigated areas, are social and economic reasons (137 ha in the Menemen WUA) and the lack of water supply in the Salihli and Ahmetli WUAs, respectively, 2319 ha and 11320 ha cannot be irrigated, respectively. Modernization seems inevitable for more effective use of our water resources. The most effective techniques in this modernization are land consolidation, renewal of irrigation channels, extension and consultancy services to farmers, and making water fees according to volume can be counted.

Modified Surface Drip Irrigation and Hydraulic Barrier Impacts on Soil Moisture and Water Productivity for Tomatoes in a Greenhouse

Considerable amounts of irrigation water of vegetable crops grown in homogenous sandy soil profiles could be subjected to deep percolation water losses due to inappropriately designed surface or subsurface drip irrigation methods. This study aimed to investigate the combined influence of implementing clay soil layer in homogenous sandy soil profile of low-tech greenhouse ridges and using modified surface drip irrigation (M-DI) on soil moisture distribution and water productivity of tomatoes. In the greenhouse, a 7.5 cm thick clay soil layer was implemented 15 cm from the soil surface of each ridge as a hydraulic barrier. Three irrigation regimes (100%, 70% and 50% of ETo) were imposed with the M-DI on tomato plants and 100%ETo with surface drip irrigation (DI) as control. Regarding economic valuation, viability was preserved for the M-DI and DI methods. The outcome indicated that soil moisture spreads more horizontally than vertically on the sandy soil above the clay soil layer. The combined effect of the homogenous sandy soil profile amendment and full irrigation (100%ETo) with the M-DI irrigation method increased the tomato fruit yield by 64.5%. Furthermore, the combined influence enhanced water productivity by the M-DI to 54.7 kg/m3 compared to 32 kg/m3 by the DI. However, M-DI demonstrated dominance over DI regarding returns, yield, and profit. Economic-wise, the M-DI requires 50% less of the lateral pipelines needed by the DI in low-tech greenhouses. Adopting the M-DI with a hydraulic barrier can improve soil moisture, water productivity, yield, and returns for tomato crops in low-tech greenhouses under sandy soil conditions. Also, the M-DI with the hydraulic clay barriers was an economically viable investment compared to the DI without clay barriers for growing tomatoes in low-tech greenhouses.

Pharmaceutical and personal care products in recycled water for edible crop irrigation: Understanding the occurrence, crop uptake, and water quantity effects

Global water scarcity poses a great challenge to agriculture productivity. Recycled water offers a promising alternative for agricultural irrigation, yet residual pharmaceutical and personal care products (PPCPs) in recycled water can transfer to edible crops during irrigation, and adversely affect food safety. Furthermore, irrigation water quantity can influence the accumulation of PPCPs in edible crops. This study comprehensively investigates the use of recycled water for agricultural irrigation by critically reviewing three key components: PPCPs occurrence in recycled water, their accumulation in edible crops, and the impact of water quantity on PPCPs accumulation. Literature analysis showed that PPCPs were present from 130 to 1400 ng/L in secondary effluent and 25–400 ng/L in tertiary effluent, with sulfamethoxazole being the most prevalent in both effluents. PPCPs uptake and accumulation varied between leafy and fruity vegetables, with diclofenac accumulating highest in leafy vegetables and fluoxetine in fruity vegetables. Furthermore, the water requirement of leafy and fruity crops vary throughout the growing season. In leafy vegetables, PPCPs accumulation in leaves is influenced by transpiration rate, with reduced accumulation occurring under limited water availability due to slower transpiration. In fruity vegetables, osmotic adjustment drives the water transport in fruits, leading to increased PPCPs accumulation under limited water conditions. This study contributes insights into PPCPs occurrence, accumulation, and irrigation water quantity, aiding in the development of effective strategies for recycled water use in agriculture.

Application of the AquaCrop model and response surface method to determine the optimum irrigation water and seeding density for wheat growing under sprinkler irrigation system

AbstractThis study aimed to determine the optimal seeding density and irrigation water for maximizing wheat yield, water productivity and income using the AquaCrop model and response surface method (RSM). The AquaCrop model was calibrated and validated using experimental data from two successive growing seasons. The AquaCrop simulations for grain yield, biomass, soil water content, evapotranspiration and canopy cover were satisfactory and acceptable. After calibration, the model simulated the grain yield for 47 years with five seeding densities and four irrigation schedules. By applying RSM to the AquaCrop model outputs over 47 years, it was found that irrigation water amounts of 747, 198 and 747 mm, along with seeding densities of 211, 188 and 208 kg ha−1, respectively, maximized the wheat yield, water productivity and profit per unit area. A seeding density of 162.4 kg ha−1 combined with a total of 350 mm of irrigation water and rainfall resulted in the highest water productivity. This study demonstrated the reliability of the AquaCrop model in predicting wheat grain yield under various irrigation and seeding density conditions, providing valuable insights for farmers and agricultural experts to optimize crop productivity and profitability.

Performance and Robustness Analysis of Advanced Machine Learning Models for Predicting the Required Irrigation Water Amount

Performance and Robustness Analysis of Advanced Machine Learning Models for Predicting the Required Irrigation Water Amount

Combination of control factors influencing application uniformity of a low-pressure pivot sprinkler spray unit

The objective of any pivot irrigation system is to ensure uniformity of application of water which can be achieved when responsible factors such as pressure, drop tube lengths, nozzle size etc. are adequately designed. This indoor experiment conducted in a 44m2 laboratory facility tends to evaluate the extent of the influence of some sprinkler design parameters on the performance of a low pressure single pivot sprinkler spay unit. The parameters considered are; pressures of 9,12, 15 and 19Psi, nozzle sizes of 4.17, 5.56, 6.95 and 8.14 mm and drop tube lengths of 1, 1.2 and 1.5m. In this experiment an inverted U-shaped frame designed to support a spray sprinkler at different heights was used. The hydraulic installation with manual throttle valves for controlling water distribution was used to supply pressurized water to the spray model sprinkler. A number of 64 graduated catch-cans with 0.16 m diameter and 0.2m height were used. The cans were arranged in eight radial legs with a distance of 1m apart. The system was run for one hour then the caught volumes were measured manually using a graduated cylinder with a capacity of 500 mL. The catch-cans data were used to determine uniformity coefficients. Line graphs were used to show relationships between the parameters measured. The experiment shows that there is strong relationship between the parameters considered. It indicated that the coefficient of uniformity (CU) and distribution uniformity of lower quarter DUlq increases with increase in nozzle size and pressure. It also shows that the largest nozzle size and pressure within the limits of this experiment gave the best CU and (DUlq) values of 96% and 90% at 1.5m height. Lager nozzle sizes with lower pressure reduces the CU and DUlq values. It is concluded from this experiment that though pressure, nozzle size and height of application influences the uniformity of application, larger nozzle sizes accompanied by higher pressure and height of application resulted in good uniformity of application. It is therefore imperative that while operating Pivot Sprinkler systems, careful selection of nozzle diameters, operating pressure and drop tube heights, sprinkler can be used to apply the ideal amount of irrigation water needed to refill the crop root zone that can neither cause runoff nor harm the crop and also provide the best uniformity possible under the prevailing wind and management conditions.

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.

Quantifying recharge mechanisms in low-hilly areas of a loess region: Implications for the quantity and quality of groundwater

Groundwater plays a crucial role in sustaining water supply and irrigation in arid regions with thick vadose zones; however, the recharge mechanisms and their impact on water quality remain contentious. For flood-irrigated areas, irrigation water amount is not well known to evaluate the effect of irrigation on the recharge. In this study, we employed multiple tracers to investigate recharge mechanisms in a low-hilly region with some flood-irrigated areas, where irrigation water recharge was estimated by the chloride mass balance method combined with the tritium peak method. Deep soil samples from irrigated lands in vadose zone and groundwater from unconfined aquifers were collected to determine the contents of the water isotopes (2H, 18O, and 3H), chlorides (Cl-), and nitrates (NO3−). The findings revealed unique tritium peaks preserved in the loess vadose zone, where the recharge rate under the non-irrigated site was estimated to be only 8.6 mm yr−1, 2.4 % of the average annual precipitation. According to the estimated irrigated recharge rates, irrigation water dominates the potential diffuse recharge in vadose zone. For the aquifer recharge, we then quantified diffuse recharge (62.2 ± 4.7 %, piston flow) and focused recharge (37.8 ± 4.7 %, preferential flow) via the line-conditioned excess (lc-excess) balance method. Focused recharge occurred in low depressions, where surface runoff carrying sediments with high solutes converged in large rainfall events during wet season. Subsequently, focused mode rapidly recharges groundwater with NO3− and Cl- elevated, deteriorating water quality of phreatic aquifer. Finally, we concluded focused recharge does not dominate aquifer recharge, but significantly affects groundwater quality. These findings underscore the implications for the sustainability of agricultural water and soil resources management, emphasizing the potential impacts of soil conservation on groundwater quality in low-hilly regions.

Water Requirement and Irrigation Scheduling of Potato (<i>Solanum tuberosum </i>L.) by Using CROPWAT 8.0 at Welmera District, Central Highland of Ethiopia

In Welmera district, due to poor management of irrigation water, determination of crop water requirements and appropriate irrigation scheduling is important to prevent over or under-irrigation. The 30-year climatic data (1993- 2023) collected from Holeta Agricultural Research Center were used to estimate potato water requirements and irrigation scheduling using CROPWAT 8.0 model. The results shows that, the CWR, NIR and GIR for potato crop was 444.9 mm, 371.7 mm and 619.5 mm respectively. For the early January planted potato, irrigation should be given fourteen times (1-Jan, 9-Jan, 19-Jan, 29-Jan, 5-Feb, 12-Feb, 19-Feb, 26-Feb, 5-Mar, 11-Mar, 19- Mar, 26-Mar, 31-Mar and last irrigation on 10-Apr) with a gross irrigation water amount of 24.2 mm, 19.9 mm, 23.3 mm, 24.2 mm, 26.9 mm, 35.5mm, 38 mm, 43.5 mm, 43.4 mm, 40.8 mm, 41.9 mm, 39.5 mm, 40.2 mm and 42.9 mm depth respectively. The results obtained from this study can be useful in preventing over or under-irrigation and for future planning of water resource, thereby helping to save water in meeting the CWRs, and can be used as a guide for farmers to select the amount and frequency of irrigation for the crop being studied.

Integrated assessment of groundwater quality for sustainable irrigation in drought-prone central districts of Odisha, India

Crop productivity relies on the quantity and quality of irrigation water, with groundwater quality playing a major role. Exploitation of groundwater for irrigation is slowly increasing in central districts of Odisha. A study was carried out in these areas to assess the groundwater quality for irrigation for sustainable use of the groundwater resources. This was done by developing a Water Quality Index (WQI) for eight parameters. The groundwater quality was assessed using a framework that utilised the entropy weight approach and Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS). This framework was employed to determine the relative proximity of each solution to the ideal solution. The TOPSIS range is divided into three categories: low quality (less than 0.1), medium quality (0.1–0.5), and good quality (0.5–0.9). The low-quality category has a percentage of 6.45%, categorized as poor quality and unfit for drinking and irrigation uses; the medium-quality category has 52.07%, and the good quality category has 41.47% of the area falls under the very good category. These parameters are essential when considering water usage for agriculture, especially in regions where farmers use fertilizers and pesticides extensively to enhance crop production.

Field-grown lettuce production optimized through precision irrigation water management using soil moisture-based capacitance sensors and biodegradable soil mulching

AbstractScientists, environmentalists, and farmers are currently in pursuit of sustainable agricultural practices that can effectively ensure global food security while simultaneously mitigating environmental degradation. A field experiment was conducted to elucidate the impact of low-cost capacitance soil moisture-based sensors on lettuce (Lactuca sativa L.) irrigation water conservation, agro-physiological aspects, and nutritional characteristics. The experiment also involved the use of five different types of soil mulching films: white geotextile (WGup), green geotextile (GGup), black plastic (BPup), white geotextile for both above and below ground (WGup-down), green geotextile for both above and below ground (GGup-down), in addition to un-mulched soil (control). The findings demonstrated that the application of WGup, BPup, WGup&down, and GGup&down resulted in a significant improvement in irrigation water conservation, with WGup exhibiting the highest savings at 41.86%, while the control group exhibited the least amount of water savings at 19.87%. Moreover, the highest productivity levels were observed in plants mulched with GGup&down, reaching 47,944.68 kg ha−1, whereas the lowest productivity was recorded in plants mulched with green geotextile GGup at 22,377.89 kg ha−1. In terms of irrigation water productivity (IWP), the order of effectiveness was BPup > GGup-down > WGup > WGup-down > GGup > Control, with BPup achieving the highest IWP at 60.19 kg m−3 and the control treatment reporting the lowest at 27.80 kg m−3. The percentage of the irrigation water applied for crop evapotranspiration (Irc) showed that the control treatment saved the least amount of irrigation water, saving only 19.87%, while the best treatment was WGup, achieved the highest percentage of irrigation water savings at 41.86%. Additionally, mulched plants exhibited higher levels of nutrients (N, P, Ca, Mg, Fe, Mn, and Zn), ascorbic acid (AsA), and total phenol content (TPC), while showing lower nitrate content in the leaves compared to non-mulched plants. Overall, the utilization of soil moisture-based capacitance sensors and biodegradable mulching films has proven to be highly effective and low cost by 16.633 US$ year−1 to enhance irrigation water productivity, growth performance, nutritional quality, and overall productivity of lettuce crops, thereby contributing to the sustainability of lettuce production in arid regions.

Interaction Effects of Water and Nitrogen Practices on Wheat Yield, Water and Nitrogen Productivity under Drip Fertigation in Northern China

Water resource shortage and unreasonable application of nitrogen (N) fertilizer have been problems in wheat production of northern China. However, the interaction effects of water regimes and N practices on wheat root growth, grain yield, soil water, and inorganic N changes as well as water-N use efficiency are still unclear under drip irrigation. A field experiment was conducted during the 2020–2021 and 2021–2022 winter wheat (Triticum aestivum) growing seasons. In this study, three irrigation schedules (i.e., irrigation was applied up to 80% [D1], 75% [D2], and 70% [D3] as soon as the soil water content decreased to 65%, 60% or 55% of field capacity) and two N practices (i.e., N applied at the base, jointing, booting stages were 90, 72, 48 kg ha−1 [N1], and the base, jointing, booting, filling stages were 90, 40, 40, 40 kg ha−1 [N2], respectively) were considered. The decease in irrigation water amount was offset by the increase in soil water consumption. In addition, N practices significantly interacted with irrigation on soil NO3−–N accumulation (2021–2022), NH4+–N accumulation, SPAD value (2020–2021), N content in stems and grains at maturity, and average root length and weight density at the flowering stage. Irrigation, rather than N practices, significantly affected grain yield, total N uptake, crop N transformations (NT), the contribution of NT to grain (NTPC), water and N productivity, in which, for the value of these two seasons, D2 increased total N uptake by 18.1% (p < 0.05), and NT by 39.4% (p < 0.05) under N1 as compared to D3. Additionally, the highest WUE and ANUE were found in D2 during 2021–2022. Heavy irrigation water amount caused high a LAI; further analysis proved that the LAI was the key factor affecting grain yield, and positively and significantly correlated to yield. However, no significant difference in the LAI between D1 and D2 was found. N1 was beneficial to prevent N leaching and increase water and N use efficiency, biomass, and N transformation amount. This study recommends that D2 + N1 might be a promising system for manipulating irrigation and fertilization practices under sub-surface drip irrigation systems to improve water and N use efficiency and grain yields in semi-arid regions.

Optimization of Irrigation Programming for Different Water Allocation Strategies at Network Level: Method and Application

AbstractOptimum irrigation programming at network level is important not only for maximum yield and benefit from the system but also for sustainable use of constrained resources. The subject of this investigation is to devise a method which enables optimum water allocation in irrigation networks, to apply it to a real system, and to analyze the results. In the first step, the irrigation district was divided into the most suitable water allocation zones considering the hydraulic properties of the canals. Next, alternative system rotation periods were defined in accordance with the properties of the research area, the hydraulic infrastructure of the irrigation network and the crop pattern. In this process, the model was run for five different water allocation strategies. The model was applied to the command area of Sarıkız Irrigation Association in the Ahmetli Regulator Right Bank Irrigation System in the Gediz Basin. Therefore, irrigation programs were prepared for the crop pattern, which receives water from 45 tertiary canals of the Y9 secondary. The irrigation time allocated to each tertiary canal and the amount of irrigation water were evaluated, together with the water shortage levels which occurred in these tertiary canals. The results indicated that the model defined the optimum system rotation period, the borders and the sizes of the most suitable water allocation zones, and the most suitable irrigation programs under the prevailing conditions. The proposed model can provide an insight for decision makers as a decision support tool.

Water Requirement and Irrigation Scheduling of Selected Vegetable Crops Grown in Welmera District, Central Highland of Ethiopia

Accurate quantification of irrigation water requirement at different physiological growth stages of crops is important to prevent over or under irrigation. A study was carried out to determine the crop water requirement and irrigation scheduling of the selected vegetable crops grown under irrigated conditions at Holeta, Central Highland of Ethiopia. The crops include, cabbage, and tomato. By using the 30-year climatic data, the crop evapotranspiration (ETc), reference crop evapotranspiration (ETo), and irrigation water requirement for each crop were determined using the CROPWAT model. The study shows that the total CWR of cabbage, and tomato was estimated to be 426.6mm, and 497.7mm respectively, and the total GIR of cabbage, and tomato was found to be 598.3 mm, and 691.7 mm respectively. for early January planted cabbage, irrigation should be given twelve times ( 1-Jan, 9-Jan, 16-Jan,24-Jan, 2-Feb, 11-Feb, 21-Feb, 5-Mar,15-Mar, 25-Mar, 2- Apr and last irrigation on 12-Apr) with a gross irrigation water amount of 59.8mm, 32.5mm, 31.5mm, 35.2mm,42.2mm,43.3mm,48.1mm, 52mm, 51.3mm, 49.5mm, 51mm, and 51.7mm depth respectively. Similarly for early January planted tomato, irrigation should be given twelve times (1-Jan, 5-Jan, 10-Jan, 16-Jan, 21-Jan, 29-Jan, 6-Feb, 15-Feb, 26-Feb, 12-Mar, 26-Mar, and the last irrigation on 10-Apr) with a gross irrigation water amount of 53.9mm, 19.3mm, 25.5mm, 30.7mm, 30.6mm, 36.4mm, 47.8mm, 58.5mm, 73.4mm, 83.5mm, 80.9mm, 80.7mm irrigation depth respectively. This study might be useful to prevent over or under irrigation which will help in effectively planning and management of irrigation water in the district.

Adjusting Irrigation and Phosphate Fertilizer to Optimize Tomato Growth and Production

The efficient use of phosphate fertilizers and optimization of the amounts of irrigation water can maximize tomato growth and fruit production. This study aimed to evaluate the effects of different phosphorus (P) doses and sources on the growth and production components of tomato plants of the cultivar Gaúcho Melhorado Nova Seleção subjected to different irrigation water percentages. To achieve this, we set up an experiment using a factorial design to test the effects of four doses of P2O5 (corresponding to 25%, 50%, 100%, and 200% of the recommended dose), two P sources (monoammonium phosphate—MAP and organomineral—OM), and four irrigation water percentages (50%, 75%, 100%, and 125% of field capacity). Tomato plant growth improved when water was supplied at a percentage close to 100% of field capacity, with increased plant height, leaf length, and number of flowers observed (increases of 11.95%, 7.33%, and 13.87%, respectively, compared to 50% of field capacity). However, both excess and deficit irrigation resulted in morphological changes in tomato plants. Additionally, we observed that OM was more effective than MAP in increasing plant diameter and number of flowers, with increases of up to 36.4% and 227.6%, respectively, when using OM. Conversely, tomato growth was negatively affected by higher doses of MAP doses, suggesting that 25% of the recommended dose may yield the best growth rates. We verified that tomato plants can compensate for low phosphorus doses by increasing productivity with higher water amounts (125%–42.40 t ha−1), but high phosphorus doses result in greater fruit production with lower water percentages (50%–41.52 t ha−1).

Response of Durum Wheat to Deficit Irrigation

Deficit irrigation trial has been conducted to see the response of durum wheat to the extent of deficit irrigation at Debre Zeit research center for three successive seasons from 2016 to 2018. Establishment irrigations were given for all plots after swing and irrigation water application events were monitored using long term meteorological data and soil moisture readings. Irrigation water application depths (amount of water applied) were calculated from cumulative crop evapotranspiration (ETc) values in a given period and plots were irrigated with depths that was replenish 100 %, 75%, and 50 % of the cumulative ETc as per the treatment to be applied. Measured amount of irrigation water applied to every plot measured by using 3 inch Parshall flume. Results indicated those grain yields significantly affected by deficit irrigation levels and furrow irrigation methods. The highest mean grain yield of 5.8 t/ha attained from 75% ETc irrigation level with alternate furrow irrigation method while the lowest mean yield of 3.989 t/ha was obtained from treatment irrigated with 50% ETc and conventional furrow irrigation method. Therefore, based on the current findings, the highest grain yield was obtained at 75% ETc with alternate furrow irrigation system while the highest WUE was recorded at irrigating 100% ETc with alternate furrow system.

The effects of drought and salinity on KS and RAW managerial coefficients in the efficient water management in maize farms

This study aimed to investigate the simultaneous effects of drought and salinity on irrigation management coefficients in maize farms. A three-year field research was conducted in the form of a 3 × 3 factorial experiment with a randomized complete block design and three replications from 2020 to 2022 in a maize farm, in Aliabad Fashafoye, Qom province, Iran. The applied treatments included three levels of salinity (S0 = 1.8, S1 = 5.2, and S2 = 8.6 dS/m) and three levels of irrigation (W0 = 100%, W1 = 75%, and W2 = 50% of field capacity). Evapotranspiration stress coefficient (KS) due to W0S1 and W0S2 treatments was (0.975 and 0.934), (0.974 and 0.932), and (0.962 and 0.935) in 2020, 2021, and 2022, respectively. According to the results, KS decreased by increasing the salinity level of irrigation water, so a 1-unit increase in salinity level above the tolerance threshold of the crop to salinity decreased KS by 0.78 and 1.76% for S1 and S2, respectively. Moreover, each percent of volumetric moisture decrease from field capacity decreased KS by 5.9 and 13.3% in W1 and W2, respectively. Also, with the increase in the intensity of the stresses, the readily available water (RAW) of treatments decreased. The sole application of salinity stress decreased the decreasing slope of RAW by 3.2%, while the application of both stresses resulted in the decreasing slopes of 4.9, 5.7, and 7.8% at the salinity levels of S0, S1, and S2, respectively, compared to the control. The findings of this study show that the accurate estimation of crop evapotranspiration and RAW can help to improve the irrigation schedule, and the amount of irrigation water used is less than in non-stress conditions due to the reduction of total evapotranspiration and less water uptake in environmental stresses in maize farms.

Trade-off between the future water resource utilization and grain production in a water-deficient region from the perspective of the Water−Land−Grain nexus

The utilization and future evolution of water resources in water-deficient regions will have a significant impact on sustainable agricultural development. The trade-off between water resource utilization and grain production in the Daqing River Basin (DRB) was explored, and the characteristics of the future evolution of the water − land − grain system was analyzed. The main planting patterns of farmland in the DRB are winter wheat, spring maize, summer maize, or a winter wheat − summer maize rotation. The total water consumption and supply are 61.6 × 108 and 54.4 × 108 m3, respectively. The water supply gap is approximately 7.2 × 108 m3, which is mainly supplemented by the overexploitation of groundwater. Under the current land use structure, grain production in the DRB has achieved self-sufficiency, but excessive water consumption in agricultural production has led to severe groundwater overexploitation. Despite the exploration and implementation of a fallow land policy in the DRB, the quantity of water resources conserved currently falls significantly short in comparison to the extent of groundwater overexploitation. From the trade-off between water resource utilization and grain production, if winter wheat areas were left completely fallow, or winter wheat planting regions establish three crops in two years or a single crop in a year, the total amount of irrigation water that could be saved was 18.4 × 108, 7.5 × 108, and 15.2 × 108 m3, although the grain production capacity would be reduced by 31 %, 12 %, and 24 %, respectively. This study proposes prioritizing fallow areas in the winter wheat planting regions with high water demand located in the Diandong Plain, and changing the current system of two crops a year to three crops in two years or a single crop a year. The implementation of this approach is anticipated to alleviate the strain on water resources. To achieve the control of groundwater overexploitation and balance the supply and demand of water resources, it is necessary to continue to expand the fallow area of winter wheat in the eastern and southern plains of Baiyangdian by approximately 25.3 × 104 hm2, or increase the amount of water diverted from outside the basin by approximately 7.20 × 108 m3. By 2030, the DRB will face the dual pressures of both water and grain security, with a water resource gap of 13.8 × 108 m3. It is therefore necessary to increase inter-basin water transfer or continue to expand the fallow area of winter wheat in the future.

The Effect of Climate Change on the Water Requirements of Wheat Crops in Al-Qurna District for the Periods (1950-1961) and (2011-2022)

Climate is one of the fundamental factors influencing various human activities, including agriculture. Climatic conditions impact the type of crops that can be grown and their water requirements, which is especially important in arid regions like the study area. Understanding these requirements helps determine the amount of irrigation water needed for crops to avoid overuse, as well as the agricultural area that can be irrigated and the water needs of wheat crops. Water consumption refers to the amount used by a crop during its growth period over a specified area to build plant tissues within a specific timeframe. The study shows that climatic elements such as solar radiation, various temperature types (mean, maximum, and minimum), wind, relative humidity, rainfall, and evaporation affect the water requirements of wheat crops in the study area. When examining the climate element changes between the periods 1950-1961 and 2011-2022, whether the change direction is positive (increase) or negative (decrease), it was observed that there were increases in solar radiation, mean temperature, maximum and minimum temperatures, and evaporation. Meanwhile, there were decreases in relative humidity, rainfall, and wind speed, with an increase in water demand for all wheat planting months, especially in October, March, and April during the 2011-2022 period. This is due to higher evaporation resulting from increased temperatures, unlike the 1950-1961 period , during which the water demand for most months was lower due to moderate climate elements.