Irrigation Water Use Efficiency Research Articles

IoT-based solar-powered smart irrigation system with solar tracker for rice fields

Water management in irrigated agricultural fields is a critical issue in Bangladesh due to a lack of improved irrigation facilities for efficient use of irrigation water, and the cost of crop production is high with low agricultural productivity in agriculture. Therefore, this research aimed to design and implement an internet of things (IoT)-based solar-powered smart irrigation system by sensing the soil moisture levels and periodically controlling the pump operations when the soil moisture is below the required level. A sun-tracking solar system was developed to generate more electricity by tracking the orientation of the sun. A comparison was made between the energy of a fixed-panel solar system with a 24.95° tilt angle and a solar tracking system with no tilt angle. The solar tracker device utilizes a Light Dependent Resistor (LDR) sensor to track the sun, aligning the 150 W solar panel perpendicular to maximize energy capture. This energy is converted into electrical energy and stored in a 12V battery for powering the operation of the submersible pump (DC 12V, 150 W). A wireless sensor network was employed to monitor pumping status and energy comparison in a rice field. A sub-station transferred water level data wirelessly to a main station, where a microcontroller processed the data. The relay module automatically triggered pumping, and the data was stored in the cloud. The solar tracking system outperformed the fixed-panel system with a fixed tilt angle of 24.95° in terms of output power by a remarkable 26.72%. There is a huge potential for solar irrigation systems in Bangladesh, and they can provide sustainable solutions with low irrigation costs. Therefore, this IoT-based solar-powered smart irrigation system could play a vital role in improving irrigation management systems with increased water use efficiency.

Monitoring plant responses in field-grown peanuts exposed to exogenously applied chitosan under full and limited irrigation levels

In recent decades, numerous studies have examined the effects of climate change on the responses of plants. These studies have primarily examined the effects of solitary stress on plants, neglecting the simultaneous effects of mixed stress, which are anticipated to transpire frequently as a result of the extreme climatic fluctuations. Therefore, this study investigated the impact of applied chitosan on boosting the resistance responses of peanuts to alkali and mixed drought-alkali stresses. Peanuts were grown in mid-alkaline soil and irrigated with full irrigation water requirements (100%IR), represented alkali condition (100% IR × alkali soil) and stress conditions (70% IR × alkali soil—represented mixed drought-alkali conditions). Additionally, the plants were either untreated or treated with foliar chitosan. The study evaluated various plant physio-chemical characteristics, including element contents (leaves and roots), seed yield, and irrigation water use efficiency (IWUE). Plants that experienced solitary alkali stress were found to be more vulnerable. However, chitosan applications were effective for reducing (soil pH and sodium absorption), alongside promoting examined physio-chemical measurements, yield traits, and IWUE. Importantly, when chitosan was applied under alkali conditions, the accumulations of (phosphorus, calcium, iron, manganese, zinc, and copper) in leaves and roots were maximized. Under mixed drought-alkali stresses, the results revealed a reduction in yield, reaching about 5.1 and 5.8% lower than under (100% IR × alkali), in the first and second seasons, respectively. Interestingly, treated plants under mixed drought-alkali stresses with chitosan recorded highest values of relative water content, proline, yield, IWUE, and nutrient uptake of (nitrogen, potassium, and magnesium) as well as the lowest sodium content in leaves and roots. Enhances the accumulation of (N, K, and Mg) instead of (phosphorus, calcium, iron, manganese, zinc, and copper) was the primary plant response to chitosan applications, which averted severe damage caused by mixed drought-alkali conditions, over time. These findings provide a framework of the nutrient homeostasis changes induced by chitosan under mixed stresses. Based on the findings, it is recommended under mixed drought-alkali conditions to treat plants with chitosan. This approach offers a promising perspective for achieving optimal yield with reduced water usage.

Learning-based multi-agent MPC for irrigation scheduling

Amid concerns about freshwater scarcity, the agricultural sector faces challenges in water conservation and optimizing crop yields, highlighting the limitations of traditional irrigation scheduling methods. To overcome these challenges, this paper introduces a unified, learning-based predictive irrigation scheduler that integrates machine learning and Model Predictive Control (MPC), while also incorporating multi-agent principles. The proposed framework incorporates a three-stage management zone delineation process, utilizing k-means clustering and hydraulic parameters estimates for optimized agro-hydrological modeling. Long Short-Term Memory (LSTM) networks are employed for accurate and computationally efficient root zone soil moisture modeling. The scheduler, formulated as a mixed-integer MPC with zone control, utilizes the identified LSTM networks to maximize root water uptake while minimizing overall water consumption and fixed irrigation costs. Additionally, the learning-based scheduler adopts a multi-agent MPC paradigm, where decentralized hybrid actor–critic agents and the concept of a limiting irrigation management zone are employed to enhance computational efficiency. Evaluating the performance on a 26.4-hectare field in Lethbridge for the 2015 and 2022 growing seasons demonstrates the superiority of the proposed scheduler over the widely-used triggered scheduling approach in terms of Irrigation Water Use Efficiency (IWUE) and total prescribed irrigation. Notably, the proposed approach achieves water savings between 7 to 23%, coupled with IWUE increases ranging from 10 to 35%.

Cover crops and irrigation impacts on corn production and economic returns

Increases in irrigated crop acreage and frequent droughts during the growing season have caused continual groundwater decline of the Mississippi River Valley Alluvial Aquifer in the Mississippi Delta region. A field experiment was conducted from 2019 to 2021 to determine if combinations of irrigation scheduling thresholds and cover crops (CCs) could improve corn (Zea mays L.) production, water productivity (WP), irrigation water use efficiency (IWUE), and net returns. The irrigation thresholds used for irrigation scheduling were a wet threshold (−40 kPa), a dry threshold (−90 kPa), and no irrigation. The CC treatments were cereal rye (Secale cereale L.), hairy vetch (Vicia villosa R.), wheat (Triticum aestivum L.)-radish (Raphanus sativus L.)-turnip (Brassica rapa L.) mix, and no cover crop. In 2020, CCs reduced corn yield by 9–26% compared to no cover crop. In 2021, wet irrigation threshold treatments had 8% and 9% higher corn yield than no irrigation and dry irrigation threshold treatments, respectively. No irrigation treatments showed higher WP than dry and wet irrigation thresholds, while hairy vetch had higher in WP among CC treatments in year two of this study. Hairy vetch under the dry irrigation threshold had higher IWUE than all other treatments. The no-CC treatments generated $167, $340, and $58 ha−1 more under the wet, dry, and no irrigation treatments, respectively, when averaged over both years. Water conservation was affected by CC selection and irrigation management.

An Evaluation System of the Modernization Level of Irrigation Districts with an Analysis of Obstacle Factors: A Case Study for North China

Irrigation districts are a pivotal infrastructure of agricultural water conservancy engineering. Implementing modernization will be the main task of large-scale irrigation districts for a considerable amount of time in the future. In this study, four typical large-scale irrigation districts in North China were investigated: the Renmin Shengliqu, Weishan, Shijin, and Zuncun irrigation districts. The concept of a modern irrigation district was deconstructed to establish an evaluation index system which includes four second-level indicators, twelve third-level indicators, and thirty fourth-level indicators. A hybrid approach based on AHP and OWA was used to quantify indicator weights used in group decision making. TOPSIS was introduced to measure the modernization level of the four irrigation districts. An obstacle factor diagnosis model was applied to search for key obstacle factors that will affect the modernization and improvement of the irrigation districts. The results showed that (1) the modernization levels of the Renmin Shengliqu, Weishan, Shijin, and Zuncun irrigation districts in 2020 and 2025 were 0.3916 and 0.5755, 0.3748 and 0.5396, 0.4493 and 0.6012, and 0.2343 and 0.6166, respectively. The evaluation results indicate that the four irrigation districts are still in the beginning phase (or even preparation phase) of the modernization process. (2) Eight indicators were identified as the main common obstacle factors for the four evaluated irrigation districts, including the irrigation water-use efficiency factor, the coverage proportion of information technology, the proportion of efficient water conservation irrigation areas, and so on. (3) There are two effective methods to enhance the modernization level of the four irrigation districts: improving water resource utilization efficiency and strengthening the management system with an emphasis on informatization. The present study can enrich the theoretical evaluation of irrigation districts and provide a scientific basis for the modernized construction and management of irrigation districts in China.

Farmers’ Knowledge on Agricultural Irrigation Programs: The Case of Altınekin District of Konya Province

Climate change-induced droughts have various negative impacts on different sectors, especially on agricultural sector. Altınekin District, where the research was conducted, has the lowest precipitation in Konya Province, therefore is expected to be most affected by drought. For sustainable use of water resources, each stage of agricultural production should be carried out within the framework of a specific program. With this study, knowledge level of farmers engaged in irrigated agriculture in Altınekin district regarding irrigation and irrigation programs they applied were determined through a face-to-face survey. Present findings revealed that 38.7% of the participant farmers are aged 50 years and over and a large proportion of them (54.7%) are primary school graduates. Participant farmers were all (100%) using groundwater resources in agricultural production and 88% of them stated that they did not receive any training on irrigation. While 32% of the farmers participating in the survey stated that they had knowledge about the concept of irrigation program, 68% reported that they did not have any knowledge. Incorrect and improper practices regarding efficient use of irrigation water in the region, especially regarding the irrigation program, were identified and solutions were proposed for these problems.

Irrigation as an Effective Way to Increase Potato Yields in Northern China: A Meta-Analysis

A meta-analysis was conducted with the aim of exploring the influence of irrigation on potato yield, evapotranspiration (ET), and water-use efficiency (WUE) in northern China, considering factors such as irrigation methods, growing region, irrigation water-use efficiency (IWUE), irrigation frequency, soil types, and nitrogen (N) fertilizer rate. Overall, irrigation significantly increased potato yield and ET by an average of 45 and 54% compared to non-irrigation, respectively, but did not significantly increase the WUE. The increase in potato yield under irrigation is the most evident in aeolian sandy soil in northeast China and northwest China. Drip irrigation demonstrated the highest positive impact on both yield and WUE. Optimal yields were achieved with an irrigation amount ranging from 100 to 200 mm, while the highest WUE was observed with an irrigation amount of 30–50 mm. When the amount of irrigation exceeded 100 mm, the irrigation significantly resulted in decreased WUE compared to non-irrigation. The relative increase in yield per unit of irrigation amount and IWUE gradually decreased and eventually stabilized when the irrigation amount exceeded 100 mm. Therefore, the yield and WUE perform best when the irrigation amount is below 100 mm and the irrigation frequency is less than three times for sprinkling and flood irrigation methods. The greatest increases in yield and WUE under irrigation were found under a moderate N rate (150–250 kg N ha−1). Additionally, the relative increase in yield per unit of irrigation amount decreases gradually as the organic matter content increases. These findings suggest that the optimal benefits from irrigation might be realized when the irrigation amount is below 100 mm, with a moderate nitrogen fertilizer application and an irrigation frequency of three times. However, it is essential to consider local environmental factors such as the growing region, soil types, and organic carbon content.

Response of tomato (Solanum lycopersicum) to varying levels of irrigation and nitrogen under trickle fertigation

An experiment was conducted during 2022 and 2023 at Lovely Professional University, Jalandhar, Punjab to study the response of tomato (Solanum lycopersicum L.) to 3 irrigation levels [I1, 70%; I2, 85% and I3, 100% of IWR] and 3 nitrogen fertilization levels [N1, 70%; N2, 85% and N3, 100% of RDN] in split plot design. On individual effect basis, the fruit yield first increased with the increase in amount of applied irrigation water in I2 (95.6 t/ha) and then decreased in I3 (93.5 t/ha). Irrigation water use efficiency (IWUE) was the highest in I2 (3.73 t/ha-cm). Plant growth, tomato yield and IWUE were significantly higher in N2 than that were found in N1 and N3. Nitrogen use efficiency (NUE) decreased with increasing nitrogen levels (N2 and N3) but it increased with increasing amount of water applied (I3). The treatments having deficit irrigation level as I1 and I2, significantly enhanced the lycopene content (27 to 33 µg/g) and reduced the nitrate content (74 to 95 mg/kg) in the fruit over full irrigation level I3. Nitrate content was highest in N3 (100 mg/kg). Among all the combination of irrigation and nitrogen fertilization levels the interaction of I2N2 (85% of IWR and RDN) was found the best to grow the drip-irrigated tomato crop. This combination gave optimum plant growth (87.5 cm), fruit yield (100 t/ha), IWUE (3.93 t/ha-cm), NUE (0.79 t/kg) and good quality fruit. The findings can be utilized for irrigation planning and nitrogen management in tomato cultivation and to conserve available fresh water resources in water scare regions of Punjab. In order to promote trickle fertigation at village level, the awareness programs for farmers could be conducted.

Effect of Deficit Irrigation and Intercrop Competition on Productivity, Water Use Efficiency and Oil Quality of Chia in Semi-Arid Regions

Intercropping offers greater scope to introduce new crops. Cultivation of crops with diverse root architecture and different durations enhances the productivity of scarce resources like land and water. This study aimed to determine the effect of intercrop competition and irrigation regimes on yield, competition, land usage, irrigation water use efficiency (IWUE), and fatty acids of chia. The field experiment was conducted in semi-arid India during 2020–2022 with full (I100) and deficit irrigation (I50) and six intercrops. Results demonstrated that chia + fenugreek intercropping in I50 improved the crops’ competitiveness, land equivalent ratio (LER) (1.77), land use efficiency (142.5%), and the IWUE of chia (23.2%). Notably, a chia + radish/spinach system in I50 reduced the seed yield (42.6–45.0%) of chia over I100 monocropping. A chia + fenugreek system in I50 resulted in a higher seed yield (196.2 kg ha−1) than chia monocropping in I100. Further, chia + fenugreek intercropping resulted in higher omega-3 content (56.68%) under I100. Therefore, a chia + fenugreek system under I100 may be suggested over monocropping for better yield and oil quality. However, during water scarcity situations, growers can adopt a chia + fenugreek system under I50 which can give a similar chia equivalent yield and a higher LER and IWUE compared to chia monocropping under I100.

Evaluation of Soil Water Tension Trigger Levels for Optimizing Peanut (Arachis hypogaea) Yield and Irrigation Water Use Efficiency

Irrigation technologies have provided the ability for growers to effectively manage crops. In recent years, soil moisture sensors have provided more precise soil moisture readings for continued improvement of irrigation decisions. Trigger level irrigation research was first performed on corn (Zea mays L.) and cotton (Gossypium hirsutum L.), but southeastern crop growers often include peanut (Arachis hypogaea L.) in crop rotations. Therefore, research was performed on peanut to determine how differing soil water tension (SWT) trigger levels affected peanut yield. Soil water tension sensors connected to a real-time data logger were used to test irrigation trigger levels in peanut plots during the 2018 and 2019 growing seasons at the University of Georgia (UGA) Stripling Irrigation Research Park (SIRP) in Camilla, Georgia. Nine different treatments were implemented, which included 20, 30, 40, 50, 60 kPa SWT, USDA-ARS Irrigator Pro, UGA Checkbook, 50% UGA Checkbook, and rainfed. Twenty-seven plots were established in a randomized complete block design with three replications. At the conclusion of this study, it was determined that there were no differences on yield within year, but year had an effect on peanut yield (P < 0.05), and treatment within year had a significant effect on irrigation water use efficiency (IWUE) (P < 0.05).

Effect of drought stress on morpho-physiological characteristics, nutritive value, and water-use efficiency of sorghum [Sorghum bicolor (L.) Moench] varieties under various irrigation systems.

Addressing water scarcity and the need for high-quality forage in arid regions necessitates the development of efficient irrigation techniques. This study assesses the impact of various irrigation methods on the performance and irrigation water-use efficiency (IWUE) of sorghum cultivars under water-deficit conditions in a semi-arid region of Iran during the 2019 and 2020 cropping seasons. Three irrigation methods-variable alternate furrow irrigation (AFI), fixed alternate furrow irrigation (FFI), and conventional furrow irrigation (CFI)-were evaluated alongside three levels of drought stress (severe stress: I50, moderate stress: I75, and full irrigation: I100) and two sorghum cultivars. The results indicated that increasing drought stress, as well as the transition from CFI to AFI and FFI, led to reductions in metabolizable energy yield (MEY), plant height, cellulose, hemicellulose, and lignin. Conversely, there were increases in leaf-to-stem ratio, digestible organic matter, metabolizable energy content, crude protein content, and IWUE for metabolizable energy production (IWUEME). The highest MEY (211.68 GJ ha-1) was recorded under CFI×I100, albeit at the expense of maximum water consumption (7261 m3 ha-1). Meanwhile, the AFI×I50 and FFI×I50 treatments exhibited the highest IWUEME (44.46 MJ m-3) and metabolizable energy content (8.736 MJ kg-1), respectively, while conserving over 60% of water. Hybrid Speedfeed outperformed in forage yield and IWUEME, while cultivar Pegah excelled in forage quality. Transitioning from CFI to AFI or FFI resulted in decreased forage yield but improved forage quality and IWUEME. Principal component analysis revealed that leaf-to-stem ratio and plant height serve as effective indicators for assessing the nutritive value and forage yield of sorghum, respectively. Considering the overall results, cultivating the hybrid Speedfeed under AFI×I75 conditions is recommended for optimal water utilization, achieving satisfactory forage yield and quality, and enhancing IWUE.

Increasing cotton lint yield and water use efficiency for subsurface drip irrigation without mulching.

Planting without mulching can eliminate the residual film pollution caused by the long-term use of plastic film covers, but it will increase soil moisture evaporation and heat loss and severely reduce water use efficiency and cotton productivity in cotton (Gossypium hirsutum L.) fields in arid regions. It is unclear whether the advantages of subsurface drip irrigation and nighttime irrigation can be leveraged to reduce the amount of irrigation applied in fields, improve the soil and leaf hydrothermal environments, and increase the synchronicity of yield and water use efficiency (WUE). Therefore, in a two-year field experiment (2019-2020), cotton was grown under different irrigation treatments (I5, 3753 m3 ha-1; I4, 3477 m3 ha-1; I3, 3201 m3 ha-1; I2, 2925 m3 ha-1; and I1, 2649 m3 ha-1). The soil volumetric moisture content, soil temperature, leaf relative water content (RWC), daily changes in gas exchange parameters, lint yield, and WUE were evaluated. The results showed that reducing irrigation can reduce the soil volumetric moisture content (0-40cm soil layer), increase the soil temperature and soil temperature conductivity, and increase the leaf temperature, intercellular carbon dioxide concentration (Ci), and WUE; however, reducing irrigation is not conducive to increasing the leaf RWC, net photosynthetic rate (Pn), stomatal conductance (Gs), or transpiration rate (Tr). There was no significant difference in WUE between the I3 and I4 treatments from 8:00 to 20:00, but the lint yield in these treatments increased by 2.8-12.2% compared to that in the I5 treatment, with no significant difference between the I3 and I4 treatments. In addition, a related analysis revealed that the positive effects of the leaf hydrothermal environment on the Pn and soil temperature on the WUE occurs during the same period (10:00-16:00). Overall, an irrigation amount of 3201-3477 m3 ha-1 applied with a subsurface nighttime irrigation system without mulching can enhance the soil moisture content and soil temperature, maintain a high photosynthetic capacity, and increase the lint yield and WUE. These results revealed that the negative impacts of plastic film contamination in arid areas can be alleviated.

Decision of Straw Deep Burial and Aluminum Sulfate Drip Irrigation in Soda Saline Soil Based on Grey Relation Analysis and TOPSIS Coupling

To investigate the impact of combining aluminum sulfate with straw and irrigation water to enhance soil quality in soda saline–alkali soil, in this study a field experiment was conducted in Tongliao City, Inner Mongolia Autonomous Region, China. With beet IM1162 as the indicator crop, four levels of aluminum sulfate dosage (30, 60, 90, 120 g m−2) and four levels of drip irrigation water quota (225, 270, 315, 360 m3 ha−1) were set. The study examined the impact of varying levels of aluminum sulfate and irrigation water on soil water salt and crop yield. Next, using a comprehensive evaluation method, the optimal quantities of aluminum sulfate and irrigation water needed for effective soil improvement were determined. The research findings indicate that the most effective treatment (W2S3) involved an aluminum sulfate dosage of 90 g m−2 and an irrigation quota of 270 m3 ha−1. This treatment resulted in significant improvements compared to the control (CK) group. Specifically, in the 0–50 cm soil layer, the following improvements were observed: the water storage capacity (SWS) increased by 51.7%; evapotranspiration (ET) increased by 16.2%; water use efficiency (WUE) increased by 55.0%; and irrigation water use efficiency (IWUE) increased by 98.1% (p < 0.05). These results emphasize the importance of optimizing the combination of aluminum sulfate dosage and irrigation water quota to improve soil conditions and crop performance. It is worth nothing that this study highlights the potential for enhancing water use efficiency and crop yield in agricultural practices, which can contribute to sustainable and efficient farming practices. The study results revealed significant improvements in soil quality and crop yield when compared to the control group (CK). Specifically, in the 0–50 cm soil layer: the soil salt content decreased by 19.8%, soil pH increased by 8.7%, and exchangeable sodium percentage (ESP) decreased by 34.0%. Moreover, the crop yield in the treatment group increased significantly, by 32.1%. These findings indicate the positive impact of the intervention on soil health and agricultural productivity. The study employed the game theory combination weighting method to comprehensively evaluate soil water, salt, and various yield indicators. The results showed that the sustainability weight for crop yield reached 0.116, emphasizing the aim of soil improvement: the sustainable enhancement of crop yield. This approach underscores the importance of balanced soil management practices to ensure long-term agricultural productivity and environmental sustainability. The comprehensive evaluation results of grey relation analysis and the TOPSIS coupling model showed that the soil improvement effect score was the highest when the dosage of aluminum sulfate was 61.7–120.0 g m−2, and the irrigation quota was 250.4–319.4 m3 ha−1, which was the recommended range for the local area. The research findings discussed in the provided sources contribute to the theoretical basis for soil improvement in soda–saline–alkali land.

The water-energy-food-ecosystem nexus in the Danube River Basin: Exploring scenarios and implications of maize irrigation

The Water-Energy-Food-Ecosystem (WEFE) nexus concept postulates that water, energy production, agriculture and ecosystems are closely interlinked. In transboundary river basins, different sectors and countries compete for shared water resources. In the Danube River Basin (DRB), possible expansion of agricultural irrigation is expected to intensify water competition in the WEFE nexus, however, trade-offs have not yet been quantified. Here, we quantified trade-offs between agriculture, hydropower and (aquatic) ecosystems in the DRB resulting from maize irrigation when irrigation water was withdrawn from rivers. Using the process-based hydro-agroecological model PROMET, we simulated three maize scenarios for the period 2011–2020: (i) rainfed; (ii) irrigated near rivers without considering environmental flow requirements (EFRs); (iii) irrigated near rivers with water abstractions complying with EFRs. Maize yield and water use efficiency (WUE) increased by 101–125 % and 29–34 % under irrigation compared to rainfed cultivation. Irrigation water withdrawals from rivers resulted in moderate to severe discharge reductions and, without consideration of EFRs, to substantial EFR infringements. Annual hydropower production decreased by 1.0–1.9 % due to discharge reductions. However, the financial turnover increase in agriculture (5.8–7.2 billion €/a) was two orders of magnitude larger than the financial turnover decrease in hydropower (23.9–47.8 million €/a), making water more profitable in agriculture. Irrigation WUE was highest for EFR-compliant irrigation, indicating that maintaining EFRs is economically beneficial and that improving WUE is key to attenuating nexus water competition. Current maize production could be met on the most productive 35–41 % of current maize cropland under irrigation, allowing 59–65 % to be returned to nature without loss of production. Maize priority areas were on fertile lowlands near major rivers, while biodiversity priority areas were on marginal cropland of highest biodiversity intactness. Our quantitative trade-off analysis can help identifying science-based pathways for sustainable WEFE nexus management in the DRB, also in light of climate change.

Relative performance of drip irrigation in comparison to conventional methods of irrigation in Indian mustard (<i>Brassica juncea</i>) in south-west Haryana

Application of water directly to the root zone through micro-irrigation system can reduce the water, fertilizer and labour requirements by improving their availability and use-efficiency. An experiment was conducted during winter (rabi) seasons of 2019–20 and 2020–21 at the research farm of CCS Haryana Agricultural University, Regional Research Station, Bawal, Haryana to study the relative performance of drip irrigation in comparison to conventional methods of irrigation in Indian mustard [Brassica juncea (L.) Czern.]. The experiment consisted 7 treatments, viz. two irrigations through flooding (as per state recommendation) at flowering and siliqua formation stage; two irrigations through sprinkler at flowering and siliqua formation stage; three irrigations through sprinkler at flowering, siliqua formation and seed development stage; and 6, 8, 10 and 12 split irrigations were applied from 30 days after sowing (DAS) through drip at 12, 9, 7 and 6 days interval, respectively. Volume of irrigation water under each treatment was same as under recommended practice of two flood irrigations (120 mm). Irrigation applied through drip at 6 days interval in 12 splits and at 7 days interval in 10 splits produced statistically similar seed yield to each other (22.51 and 21.94 q/ha, respectively) and significantly higher than recommended irrigation practice (18.92 q/ha) and sprinkler method of irrigation (18.62 and 19.32 q/ha) during 2019–20. The irrigation through drip in 12 splits (10 mm each) at an interval of 6 days between 30 to100 days after sowing also recorded the highest irrigation water-use efficiency (IWUE) (188 and 181 kg/ha-cm in 2019–20 and 2020–21, respectively). Based on these findings, it can be suggested to apply irrigation in Indian mustard through drip in 12 splits (10 mm depth each) at an interval of 6 days between 30 to100 DAS to get higher yield and water use efficiency.

Evaluation of Water Balance and Water Use Efficiency with the Development of Water-Saving Irrigation in the Yanqi Basin Irrigation District of China

Irrigation water is the main type of water consumption in the Yanqi Basin irrigation district of Xinjiang, which is an oasis-type irrigation district in the arid region of Northwest China. With the continuous expansion of cultivated areas, there is an increasing demand for irrigation water, resulting in an irrigation efficiency paradox and the phenomenon of “the more water-saving, the more water-scarce”. In this study, the water balance method and the improved IWMI (International Water Management Institute) water balance method were used with remote sensing and statistical data from 1980 to 2020 to analyze the changes in the irrigation water supply, consumption, and loss for improvement in irrigation water use efficiency (IWUE) in the Yanqi Basin. The results showed that there was an upward trend in the cultivated land area in the irrigation district of Yanqi Basin, as monitored with remote sensing from 1980 to 2020, and the values from the remote sensing data were higher than those from the yearbooks. According to the remote sensing data, the arable land area in the irrigation district increased from 1672 km2 in 1980 to 2494 km2 in 2020, thus showing a trend of expansion. The traditional water use efficiency in the irrigation district showed an increasing trend. The lowest value for the field water-use coefficient was 0.70 in 1998, and it exceeded to 0.81 from 2009 to 2020. The canal water-use coefficient was as low as 0.50 in 1998 and increased from 0.54 in 2009 to 0.82 in 2020. The irrigation water-use coefficient increased from 0.35 in 1998 to 0.68 in 2020, with a general upward trend. In this study, the water consumption ratio indicator DFg (depleted fraction), determined using the improved water balance method, increased from 0.8390 in 1980 to 0.8562 in 2020, although it showed an overall decreasing trend, and the average was 0.8436. Cultivated land’s actual irrigation water consumption per unit area reached the highest value of 8.41 × 106 m3/hm2/a in 2011 and the minimum value of 4.01 × 106 m3/hm2/a in 2020, and from 1980 to 2020 it showed a decreasing trend, while the total water diversion showed an increasing trend due to the continuous expansion of arable land. From 1980 to 2020, water diversion into the irrigation district changed from 1.214 km3 to 1.000 km3, and it reached a maximum of 1.593 km3 in 2000; water diversion into the irrigation district showed an overall upward trend. The positive impact of the post-2000 water conservation phase with the adaptation of water-saving irrigation technology was clear, as the findings showed an increase in IWUE in the Yanqi Basin irrigation district. These results provide a theoretical basis for breaking the paradox of irrigation efficiency, which can be used in the water resource management of irrigation districts.

English

Drought is a highly important abiotic stress that affects crops around the world and especially under the Mediterranean climate. This study is focused on strawberry, an important species around the Mediterranean that is suitable for family-owned smallscale businesses. This study aimed to determine the effects of conventional deficit irrigation and fixed partial root drying techniques on the evapotranspiration (ET), yield and quality of Rubygem strawberry species. Strawberry seedlings were planted in the greenhouse in a double row at a planting distance of 30×30 cm. Irrigation was carried out by drip irrigation. The control - full irrigation was based on measurements taken from an A-Class Evaporation Pan. Three conventional deficit irrigation (DI80, DI60 and DI40) and four fixed partial root drying (FPRD100, FPRD80, and FPRD60 FPRD40) were examined. Irrigation water quantities were applied at the 100% (FPRD100/FULL), 80% (DI80 and FPRD80), 60% (DI60 and FPRD60) and 40% (DI40 and FPRD40) levels. The amount of irrigation water ranged between 199.17 and 452.92 mm. It was found that the various water levels affected the ET and the yield (Y). In general, as the amount of water decreased, the ET also decreased. The ET, Y, water use efficiency (WUE) and irrigation water use efficiency (IWUE) were significantly affected by irrigation treatments (LSD 5%). The yield values are ranked from high to low as FULL > FPRD100 > FPRD80 > DI80 > DI60 > FPRD60 > FPRD40 > DI40. As expected, WUE and IWUE values were higher under deficit irrigation levels i.e., DI80, DI60, DI40, FPRD80, FPRD60, and FPRD40. Fruit quality parameters (width, height and average weight) increased with the increase in the amount of applied irrigation water. In addition, fruit firmness values and total phenolic compounds were significantly affected by irrigation level. The results showed that different irrigation levels (100%, 80%, 60% and 40%) affected the yield and yield parameters of strawberry plants. In general, it has been found that, the yield and quality are negatively affected with increases in water deficit (DI40 and FPRD40 treatments). However, the results showed that the fixed partial root drying technique is superior to conventional deficit irrigation applications. As a result of the research, mainly FPRD80 and then DI80, DI60 and FPRD60 are recommended for strawberry cultivation, especially in arid and semiarid regions, depending on the availability of water

Response of soil water, temperature, and maize productivity to different irrigation practices in an arid region

Irrigation combined with plastic film mulch (IPFM) is widely used in arid areas to alleviate water shortages and increase crop yields. However, the mechanisms by which IPFM affected soil water content (SWC) and soil temperature (ST) to promote crop photosynthesis and resources (water, nitrogen and radiation) utilization are unclear. A field experiment was conducted in northwestern China in 2019 and 2020 to evaluate the effects of different irrigation methods combined with transparent film mulching (70% cover) on soil hydrothermal conditions and maize growth, photosynthetic characteristics, yield, and resource use efficiency. The four treatments included border irrigation with no mulching (CK), border irrigation under film mulching (TM), ridge irrigation under film mulching (RM), and drip irrigation under film mulching (DM). Our results showed that TM and RM significantly improved SWC, enhanced photosynthetic rate (Pn), and lowered non-photochemical quenching (NPQ) in maize relative to CK. The DM treatment had wetter soil and lower soil surface temperatures from the V12 to R3 stage, further accelerating maize photosynthesis and resource use relative to the other treatments and thus producing the higher leaf area index and biomass accumulation. The results suggest that DM is an efficient farming strategy, increasing yield by 3.7 − 61.3%, radiation use efficiency for maize grain yield (RUEGY) by 2.8–44.3%, irrigation water use efficiency (IWUE) by 29.7–96.5%, partial factor productivity of nitrogen (PFPN) by 3.7–61.3%, and economic benefit by 12.4–100.0% relative to the other treatments. In addition, the regression function revealed that the increased soil water storage and decreased ST from VT to R3 stages helped increase maize yield. Thus, we recommended DM practice for increasing maize production in arid areas and proposed soil water storage in 0–120 cm profile ranging 342–389 mm and ST ranging from 18.9° to 22.1°C as reference management indicators.

Drought resistance, quality characteristics and water‐yield relationships of some wheat (Triticum aestivum L.) lines and varieties

AbstractThe aim of this study was to determine the drought tolerance of four different genotypes, including two wheat varieties (Ceyhan 99 and Sagittario) and two wheat lines (Zdeb101 and Zdeb102), and create irrigation schedules. This study was performed with treatments applied at three irrigation levels (S100: treatment where the entire water need of the plant was met, S50: 50% of the water provided in the S100 treatment, S0: Rainfed), with four genotypes and four replications in a split‐plot design in Kahramanmaras East Mediterranean Transitional Zone Agricultural Research Institute in 2019 and 2020. The Ceyhan 99 and Sagittario varieties, which are widely cultivated in the region and the Zeb101 and Zdeb102 lines that are candidates for varieties were used in the study. In the study, 217.1 and 213.77 mm of water was given to S100, 108.54 and 106.88 mm of water was given to S50, and no irrigation was provided to S0 in 2019 and 2020, respectively. The effects of different irrigation levels on yield, water use efficiency (WUE), irrigation water use efficiency (IWUE), protein content and wet gluten content were investigated. At the end of this study, seasonal evapotranspiration (ET), irrigation water and yield decreased from S100 to S0. WUE, IWUE and yield response factor (Ky) values showed different trends in both years. There was no significant difference in yield between the varieties. However, in the stress susceptibility index (SSI) analyses of the genotypes, it was found that the most drought‐tolerant genotypes were Zdeb102 (0.50) and Ceyhan 99 (0.54). The highest protein content and wet gluten content were found as 11.38% and 22.24% in the Sagittario variety, respectively. It is recommended that Zdeb102 and Ceyhan 99 be cultivated in regions such as Kahramanmaras which have semi‐arid climate characteristics in the Mediterranean.

Assessing the effect of deficit drip irrigation regimes on crop performance of eggplant

Irrigation of eggplants tremendously increases their yields amidst climate change. However, little is known about the deficit irrigation level for optimum growth of eggplant crops. This study investigated the effect of deficit drip irrigation on performance of eggplants to guide improvement in irrigation water use efficiency (IWUE). The study was conducted on sandy clay loam soil for two growing seasons using a randomized complete block design (RCBD) field experimental set up. The considered treatments were: percentages of Field Capacity (FC) as T1: 25 % FC; T2: 50 % FC; T3: 75 % FC; T4: 100 % FC; with a control being no irrigation (T0: 0 % FC), and all were performed in triplicates. Irrigation scheduling was based on the readings of the ML3 Thetaprobe sensor from which the soil moisture deficit was calculated and adjusted to percentages corresponding to the different treatments, under supplementary irrigation. All Treatments were subjected to the same agronomic treatments. Plant growth parameters, yield, IWUE, and fruit quality parameters were determined. Analysis of Variance was performed with R Studio software at 5 % significance level, and Tukey multiple comparison test was used for separating the means. Results showed that plant growth, yield, IWUE, and crop quality parameters significantly differed (p < 0.05) across the deficit levels. The highest mean yield, and IWUE of 39.1 ton/ha and 18.1 kg/m3 respectively were obtained in T3. The lowest mean yield was 13.5 ton/ha in T0, while the lowest mean IWUE was 6.2 kg/m3 in T1. The results imply that T3 is a limit of crop water application beyond which yield and IWUE of eggplants cease to increase and thus, start reducing. This study therefore, concludes that irrigating eggplants at 75 % FC maximizes yield and water saving in sandy clay loam soil.