Irrigation Water Productivity Research Articles

Improvement of grain weight and crop water productivity in winter wheat by light and frequent irrigation based on crop evapotranspiration

Efficient use of scarce water resources to maximize yield and crop water productivity (WPc) is a common goal of sustainable and ecological agriculture in the North China Plain. To clarify whether light and frequent (LF) irrigation under the same or reduced amount of irrigation is beneficial to achieve this goal, and to further tap the water saving potential. Based on drip irrigation conditions, a three–year (2020–2023) field experiment was conducted to investigate the effect of four irrigation treatments (CK, conventional irrigation at the jointing and anthesis stages; LF1, 100 % ETc, ETc is the crop evapotranspiration; LF2, 75 % ETc, LF3, 50 % ETc) on yield, water consumption characteristics, leaf photosynthetic physiology and grain filling process. The results showed that compared with CK, LF1 and LF2 significantly increased the photosynthetic rate and chlorophyll content of flag leaves at 18 days after anthesis, promoted grain filling, and finally enhanced dry matter accumulation after anthesis, 1000–grain weight (TGW) and grain yield. LF irrigation management mode also increased the consumption of deep soil water (1.4–2.0 m), reduced soil water consumption and evapotranspiration, and significantly improved WPc and irrigation water productivity. However, LF1 and LF2 did not have significant yield enhancement in the wet year, but had one less irrigation than in the normal year. The LF2 achieved the highest WPc in three years (2.1 kg m–3), in the 25 % (37.5 mm) and 40 % (60 mm) less irrigation water in the normal and wet years, respectively. Meanwhile, the LF3 treatment reduced the number of spikes, TGW and dry matter accumulation to different degrees in three years, resulting in significantly lower yields (13.9 %–18.4 %), which cannot be used as a reference for an efficient irrigation system. Therefore, LF irrigation based on 75 % ETc is the best irrigation strategy to improve water utilization and yield in the North China Plain.

Effects of drip irrigation coupled with controlled release potassium fertilizer on maize growth and soil properties

Drip irrigation and the application of controlled-release fertilizers are two effective and important technical measures to conserve water and fertilizer resources and promote the growth and development of maize. However, the underlying physiological mechanism of how drip irrigation combined with controlled release potassium chloride affects maize production and soil properties remains unknown. In different soil water conditions, pot experiments were conducted during the summer maize growing season in 2022 and 2023 to measure maize grain yield, irrigation water productivity, apparent recovery efficiency of potassium, plant physiological characteristics, and soil enzyme activities under the coupling of two irrigation methods (flood irrigation and drip irrigation) and three potassium fertilizer types (potassium chloride (KCl), controlled release potassium chloride (CRK), and 70 % CRK mixed with 30 % KCl). The results revealed that drip irrigation had 6.5–8.1 % and 6.7–9.4 % higher average soil volumetric water content and 3.8–8.1 % and 4.5–13.0 % higher irrigation water productivity than flood irrigation in the two maize growth seasons, respectively. Under the drought conditions, the treatments of 70 % CRK-30 % KCl application led to a significant increase in maize yield by 9.5–10.7 % and 12.2–16.8 % and apparent recovery efficiency of potassium by 8.3–14.2 % and 10.7–10.8 % compared to CRK application treatments in 2022 and 2023, respectively. Compared with the other treatments, the treatment of drip irrigation coupled with 70 % CRK-30 % KCl application under drought conditions (DIDMK) resulted in 4.5–28.7 % and 1.1–31.9 % higher grain yield, 8.2–64.4 % and 8.6–66.8 % higher irrigation water productivity, and 5.9–28.0 % and 6.7–18.9 % higher apparent recovery efficiency of potassium in 2022 and 2023, respectively. Meanwhile, the leaf net photosynthetic rate, rubisco, catalase, peroxidase, and soil enzyme activities of DIDMK treatment were also maintained at a high level. Our results indicated that drip irrigation coupled with 70 % CRK-30 % KCl application were the optimal water and potassium supply modes for maize production. This study can provide useful information regarding summer maize sustainable production and provide theoretical and technical support for summer maize irrigation and potassium fertilizer application technologies in water-scarce regions of China and other similar regions around the world.

Enhancing irrigation water productivity using short-range ensemble weather forecasts at basin scale: A novel framework for regions with high hydro-climatic variability

Integrating short-term weather forecasts with crop growth models has emerged as a valuable decision-support tool for enhancing irrigation water productivity in water-intensive crops. Our primary focus lies in formulating a simplified Quasi-Farmer Behavior Routine to utilize ensemble weather forecasts to provide irrigation guidance. The study proposes the concept of Rainfall Confidence Quotient (RCQ) that is optimized based on the forecast uncertainty levels for rainfall categories that affect the irrigation decision. We utilize two publicly available ensemble weather forecasts from NCEP-GEFS and ECM and a regionally fine-tuned high-resolution Weather Research and Forecasting (WRF) ensemble forecast system with a 3-day lead time. We have refined our methodology by conducting 800 simulation experiments across diverse scenarios, each reflecting distinct climate regimes, soil types, cropping seasons, and management practices. The proposed method consists of a sequential 3-checkpoint algorithm incorporating ensemble rainfall forecasts, antecedent soil moisture, and evapotranspiration. During the wet crop season of 2015–16, the enhanced methodology yielded a substantial increase in irrigation water productivity (IWP), averaging around 20–30 % increase across spatial locations, in contrast to the conventional irrigation practices that do not consider weather forecasts. However, during 2016–17, a dry year, the improvement in IWP only ranged between 2–10 %. On average, water savings (at field scale) of 200–500 mm were recorded in the wet year crop season of 2015–16, while 100–300 mm of water savings were achieved during the dry year crop season of 2016–17, without any considerable reductions in the crop yield. The robustness and adaptability of the developed approach have been established through comprehensive evaluation with field observation and remote sensing techniques, suggesting its potential scalability to similar hydro-climatic typologies across the world.

Monitoring small-scale irrigation performance using remote sensing in the Upper Blue Nile Basin, Ethiopia

Temporal and spatial irrigation performance indicators are crucial in informing decisions for improving the efficiency and sustainability of water and land resources. However, evaluating these indicators requires reliable and cost-effective data, which is challenging to obtain, particularly for small-scale irrigation schemes. This study aimed to assess the performance of a small-scale irrigation scheme using remote sensing and ground truth data for the 2021/22 and 2022/2023 irrigation seasons employing the Shimburit irrigation scheme in Northwestern Ethiopia, predominantly cultivated with wheat, as a case study. The performance indicators, including equity, adequacy, overall consumed ratio (OCR), and productivity, were assessed. The actual evapotranspiration (ET), the main input for performance assessment, was estimated using the surface energy balance for land – improved (SEBALI) model in the Google Earth Engine (GEE) platform. The results revealed good equity within the scheme, with a coefficient of variation of ETa value per field inside the scheme are 1.90 and 1.63 for the respective seasons. The water use adequacy across the fields was assessed to be very good in the two seasons. The scheme's overall consumed ratio (OCR) was 0.54 and 0.43 during the two subsequent seasons. Water productivity of wheat is 3.03 kg/m3 and 3.06 kg/m3 in the two seasons. However, due to untimely rainfall during harvest, land productivity declined from 3.25 tons/ha in the first season to 2.08 tons/ha in the second season. The study demonstrates the potential of using remote sensing to evaluate irrigation performance indicators and water productivity in smallholder irrigated fields.

Irrigation termination has the potential to improve cotton yield and quality on different soil types

AbstractIrrigation termination timing is challenging for cotton producers in humid regions, especially for fields with varying soil types. A field experiment was conducted in Jackson, TN, to investigate the best cotton irrigation termination on different soil types. The water management treatments consisted of rainfed conditions (RF) and terminating irrigation 2 weeks before the first crack boll (ITBC1 and ITBC2), at the first crack boll (ITC1 and ITC2), and 2 weeks after the first cracked boll (ITAC1 and ITAC2). The irrigation rates consisted of normal irrigation (2) and increased irrigation (1) during the 2 weeks prior to irrigation termination. Irrigation treatments were implemented on three soils: a low, an intermediate, and a high available water‐holding capacity (AWHC) soil. In sandy soil, seed yield increased by 127% in 2015 with the ITAC1 treatment and by 313% in 2016 with the ITC1 treatment, compared to the control (RF). These treatments were also found to be optimal for lint yield and irrigation water productivity in their respective years. The high AWHC soil did not require any irrigation in either growing season to optimize yield. In fact, irrigating at a high rate at every termination date caused yield loss in 2015. These results indicate that cotton can benefit from later termination and higher irrigation rates when soil water and rainfall are low at the end of the growing season or be harmed when the opposite is true.

Increasing Hybrid Rice Yield, Water Productivity, and Nitrogen Use Efficiency: Optimization Strategies for Irrigation and Fertilizer Management.

Water and fertilizer are crucial in rice growth, with irrigation and fertilizer management exhibiting synergies. In a two-year field study conducted in Yiyang City, Hunan Province, we examined the impact of three irrigation strategies-wet-shallow irrigation (W1), flooding irrigation (W2), and the "thin, shallow, wet, dry irrigation" method (W3)-in combination with distinct fertilizer treatments (labeled F1, F2, F3, and F4, with nitrogen application rates of 0, 180, 225, and 270 kg ha-1, respectively) on rice yield generation and water-fertilizer utilization patterns. The study employed Hybrid Rice Xin Xiang Liang you 1751 (XXLY1751) and Yue Liang you Mei Xiang Xin Zhan (YLYMXXZ) as representative rice cultivars. Key findings from the research include water, fertilizer, variety, and year treatments, which all significantly influenced the yield components of rice. Compared to W2, W1 in 2022 reduced the amount of irrigation water by 35.2%, resulting in a 42.0~42.8% increase in irrigation water productivity and a 25.7~25.9% increase in total water productivity. In 2023, similar improvements were seen. Specifically, compared with other treatments, the W1F3 treatment increased nitrogen uptake and harvest index by 1.4-7.7% and 5.9-7.7%, respectively. Phosphorus and potassium uptake also improved. The W1 treatment enhanced the uptake, accumulation, and translocation of nitrogen, phosphorus, and potassium nutrients throughout the rice growth cycle, increasing nutrient levels in the grains. When paired with the F3 fertilization approach, W1 treatment boosted yields and improved nutrient use efficiency. Consequently, combining W1 and F3 treatment emerged as this study's optimal water-fertilizer management approach. By harnessing the combined effects of water and fertilizer management, we can ensure efficient resource utilization and maximize the productive potential of rice.

Deep vertical rotary tillage reduced soil salinity and improved seed cotton yield and water productivity under limited irrigation in saline-alkaline fields

Water scarcity and soil salinization severely limit cotton production in arid areas on the globe. A two-season (2020 and 2021) field experiment was performed on cotton under film-mulched drip irrigation in south Xinjiang of China to explore the responses of soil moisture, soil salinity, root growth, seed cotton yield and water productivity to deep vertical rotary tillage (DVRT) depth (T20: 20 cm, T40: 40 cm, T60: 60 cm, Tck: 20 cm, traditional rotary tillage) in saline-alkaline fields under two irrigation amounts (W1:360 mm, W2: 480 mm, local irrigation amount). It was found that the soil moisture storage (0–120 cm) increased with as irrigation amount increased and decreased with increasing DVRT depth. Soil electrical conductivity in the root zone (0–60 cm) and 0–120 cm soil layer declined as irrigation amount and DVRT depth increased. Irrigation amount and DVRT depth had significant effects on root length density, root mass density, root/shoot ratio, and seed cotton yield, all of which increased with increasing irrigation amount and DVRT depth. Under W2, T20, T40 and T60 increased seed cotton yield by 23.3 %, 45.3 %, 65.6 % in 2020, and by 38.9 %, 62.0 % and 84.1 % in 2021 compared with TCK, respectively. Both water productivity and irrigation water productivity increased with increasing DVRT depth. There were significant positive correlations among seed cotton yield and leaf area index, dry matter accumulation, harvest index, root length density, root mass density, root/shoot ratio, water productivity and irrigation water productivity. W1T60 was suggested for cotton production in the saline regions of southern Xinjiang. The DVRT offset the decrease in seed cotton yield under limited irrigation, which indicates that DVRT is promising to reduce soil salinity and improve seed cotton yield and water productivity in saline-alkaline fields for coping with water scarcity and soil salinization.

Seedbed management, transplanting methods and irrigation regimes influence the growth, productivity and economics of summer rice (Oryza sativa L.)

A field experiment was conducted during the rabi (winter) seasons of 2017–2018 and 2018–2019 at the Central Research Farm under Bidhan Chandra Krishi Viswavidyalaya, West Bengal, India, to study the effects of planting techniques, irrigation regimes, and nursery bed management on the growth, yield, nutrient dynamics, water productivity, and economics of summer rice (cv. Shatabdi) production. The experiment was performed in a strip-split plot design with twelve treatment combinations, which were replicated three times. The design consisted of two types of transplanted rice establishment methods (viz., puddled transplanted rice (PTR) and nonpuddled transplanted rice (NPTR)) allocated to the main plot, three irrigation regimes (three-day intervals; six-day intervals; nine-day intervals) allocated to the subplot, and two nursery bed management practices (conventional seedbed and improved seedbed) allocated to the subplot. Higher growth attributes, such as plant height, tiller count, biomass, and LAI, were found under nonpuddled conditions at the time of harvesting. Similarly, a three-day irrigation interval and improved seedlings led to better growth traits. The yield attributes and yield varied nonsignificantly among the crop establishment methods. However, the lowest irrigation intervals accounted for 53.78% and 43.02% greater grain yield than did the nine-day intervals in two consecutive years, respectively, and produced statistically similar yields with six-day intervals. The percentage of seedlings transplanted from improved seedbeds was 4.01 and 4.13% greater than that from conventional seedlings. A similar trend was observed for both input and irrigation water productivity, except that the nine-day irrigation interval resulted in significantly greater water productivity than did the other intervals. The treatment consisted of nonpuddled transplanted rice along with six six-day irrigation intervals and improved seedbed management, resulting in the highest net return and benefit:cost ratio due to the low production cost. Thus, it can be concluded that transplanting seedlings into nonpuddled soil from an improved seedbed with intermittent irrigation might be the most judicious and recommended in terms of productivity as well as profitability for summer rice production.

Effect of Biochar on Dwarf Green Coconut Orchard Yield and Irrigation Water Productivity

ABSTRACT The high irrigation water demand of coconut trees in semiarid regions makes rational use crucial for crop sustainability. Additionally, it produces residues that could improve the soil water holding capacity. This research aimed to evaluate the application of coconut shell biochar to an irrigated dwarf green coconut palm orchard. The study was carried out from January 2019 to December 2021 at Campo Experimental do Curu, Paraipaba, Brazil, belonging to Embrapa Agroindústria Tropical. The experiment consisted of a completely randomized design with five treatments and four replications and included the application of 0, 5, 10, 20, or 40 g of biochar per kg of soil, equivalent to 0.0 kg, 0.5 kg, 1.0 kg, 2.0 kg or 4.0 kg of biochar per plant, respectively. The following biometric variables were evaluated: number of leaves per plant (NL), plant height (PH), number of leaflets per leaf (LFT), canopy diameter (CD) and fruit production: number of bunches per plant (NB), number of fruits per plant (NF), volume of coconut water per fruit (CWF) and total soluble solids (TSS) (°Brix), as well as the daily soil moisture average. The results showed beneficial effects on the number of leaves per plant, fruits per plant, soil moisture and irrigation water productivity in terms of liters per fruit, liters per coconut water and fruits per cubic meter (m3) applied with ideal biochar doses estimated to be 1.40 kg, 1.72 kg, 1.79 kg, 1.56 kg, 1.48 and 1.68 kg of biochar per plant, respectively.

Water productivity, yield response factors, yield and quality of alfalfa cultivars in semi-arid climate conditions

This study was carried out for 2 years (2020 and 2021) to elucidate the effects of water stress on yield and quality of alfalfa cultivars, to determine the water-yield and quality relations and the susceptibility of cultivars to water stress. Three different irrigation treatments (100%, 75% and 50% of full irrigation, I100, I75 and I50) and 12 different alfalfa cultivars (SHN, Osmanağa, Şahin 42, Minerva, Elçi, Riviera Vicentina, Magna 601, Magnum V, Prosementi, Ezzelina, Sunter, Nimet) were used in present experiments conducted in randomized-blocks split-plots design with 3 replications to investigate effects of irrigation levels on water, yield and quality parameters of alfalfa. Present findings revealed that water stress decreased crop water productivity, but increased irrigation water productivity of alfalfa cultivars. Herbage yields of the cultivars varied between 48.20 and 64.98 t/ha, hay yields between 11.42 and 14.67 t/ha and protein yields between 2.22 and 3.07 t/ha. Alfalfa was found to be sensitive to water stress in terms of herbage yield, but more tolerant in terms of hay and protein yields. Morphological characteristics (plant height, number of stems per plant, number of main stem branches and root crown diameter) decreased with increasing water stress levels. In terms of quality traits, while acid detergent fiber (ADF), neutral detergent fiber (NDF), crude fiber and crude ash ratios increased, crude protein ratios decreased with increasing irrigation water levels. It was concluded based on present findings that water stress resulted in different responses of different alfalfa cultivars and although it increased quality traits in general, it decreased herbage, hay and protein yields. Again, based on present findings, Magna 601 cultivar could be recommended for semi-arid regions.

Enhancing the irrigation water productivity of rice farming: A study on sowing and irrigation practices in Pakistan

AbstractIn Pakistan's arid agricultural landscape, this 4‐year (2020–2023) study on silty loam soil examined the relationships between sowing methods, irrigation practices, rice yield and water productivity. Using a randomized split block design, no tillage (NT) with alternate wetting and drying (AWD) and a furrow‐irrigated narrow bed (NB) emerged as being consistently competitive, showing potential for sustainable rice cultivation. Key findings indicate that AWD significantly enhances water productivity (11–35%) and increases yield (2–10%) compared to conventional practices. Drip‐irrigated wide beds (WBs) conserve substantial amounts of water (73%) but may compromise rice yield (4–47%). This study provides valuable insights into the dynamic outcomes and distinct performance trends of different rice varieties. The results suggest a potential maximum yield increase of 2–22% through optimized practices, and replacing rice may increase yield by 25–231%. Conversely, the selection of improper irrigation schedules and sowing methods for the given soil and crop conditions may lead to a yield reduction of up to 47% in high‐yielding rice varieties. These findings may help to establish a foundation for further research investigating informed decision making for sowing and irrigation methods. The potential scalability of the identified technologies and further in‐depth simulation strategies across diverse agroecological zones in Pakistan holds promise for widespread adoption, enhancing the sustainability of rice farming in the region.

Intelligent fertigation improves tomato yield and quality and water and nutrient use efficiency in solar greenhouse production

Intelligent fertigation is a sustainable solution for optimising water and fertiliser input, thus minimising environmental pollution in vegetable cultivation facilities and reducing labour costs in agricultural practices. It is important to optimise irrigation scheduling parameters to specific crops to ensure water and nutrient use efficiency. A field experiment was conducted in Shouguang, Shandong Province, to investigate the effects of irrigation scheduling with different treatments (farmer drip irrigation FI, intelligent irrigation II1, and intelligent irrigation II2) on tomato growth, irrigation water and nutrient use efficiency over two growth seasons. Intelligent irrigation II1 and II2 utilised FDR sensors to control the moisture range within 80–95% and 80–85% field capacity (FC) for automatic irrigation scheduling, respectively. Intelligent irrigation (II1 and II2 treatments) reduced irrigation rate by 24.3–63.8% in comparison with FI treatment, significantly increasing total dry matter accumulation, nutrient uptake, yield and fruit quality of tomato. II2 treatment further reduced the irrigation rate by 31.6–32.3% compared to II1 treatment, with no significant difference in tomato yield and quality. Root dry matter, root-shoot ratio, 0–2 mm diameter root length and root surface area, 0–1.5 mm diameter root tips, and >3.5 mm diameter root volume were significantly increased under intelligent irrigation treatments. Positive correlations between irrigation water productivity; nitrogen, phosphorus, and potassium use efficiency; and the indices of length, surface area, tips, and volume of roots were highly significant. Intelligent fertigation system (IFS) maintained soil moisture within a suitable range through high-frequency irrigation scheduling, promoted the growth of 0–2 mm diameter roots, which were responsible for absorbing, acquiring, and transporting water and nutrients in the soil, and reduced water loss and nutrient leakage. Taken together, the intelligent fertigation system presented herein is an effective fertigation strategy to improve irrigation water and nutrient use efficiency.

Effect of establishment methods in rainy season (kharif) and tillage practices in winter season (rabi) on yield and economics of rice (Oryza sativa)–maize (Zea mays) cropping system under coastal saline ecosystem

A field experiment was carried out during 3 consecutive rainy seasons (kharif) June–November and winter (rabi) December–May seasons of 2013–16 at Canning Town, West Bengal to evaluate 3 rice (Oryza sativa L.) es tablishment methods, viz. dry direct seeding (DSR), unpuddled transplanting (UNPT) and puddled transplanting (PT), followed by 3 tillage practices for sowing rabi maize (Zea mays L.), viz. zero tillage (ZT), conventional tillage (CT) and raised bed sowing (RBS). The DSR was done in the last week of May when the soil salinity was higher (12–15 dS/m); however, it reduced to 4–5 dS/m in the month of June due to leaching of salts by monsoon rain. The transplanting in the UNPT and PT plots was done during the first week of July using 40 days old seedlings. Submergence caused by the heavy rain, affected the transplanted rice (PT and UNPT) but not the DSR, as the plants with DSR were sufficiently above the standing water due to higher plant height. The mean grain yields in 3 establishment methods of rice (5,117; 4,477 and 4,740 kg/ha in PT, UNPT and DSR respectively) were statistically at par. However, net returns ( 36,000/ha) and benefit: cost ratio (2.2) were the highest in DSR owing to 24% re duction in cost of cultivation than PT rice. The positive effects of DSR also observed on the succeeding rabi maize crop in terms of 7.4 ha-cm less irrigation water requirement and 27% higher irrigation water productivity. Maize gave the highest yield (5,600 kg/ha), net returns ( 37,910/ha) and benefit: cost ratio (BCR) 1.86 with RBS tillage practices. The system rice-equivalent yield, net returns and BCR were 11,659 kg/ha, 77,470/ha and 2.05, re spectively, for dry direct-seeded rice-raised bed sown maize with higher mean irrigation water productivity (79 kg/ ha-cm) and energy productivity (461 kg/GJ) of rabi maize.

Optimizing Crop Water Productivity in Greenhouse Pepper

Although advanced production systems have been developed in the last 20 years, water scarcity is still a growing problem in agriculture. This study aims to evaluate the effect of different strategies that combine the application of seaweed and microbial biostimulants with regulated deficit irrigation (RDI) strategies on the irrigation water productivity (WPI), fruit quality parameters and soil enzymatic activity in pepper plants (Capsicum annum sp.) under two commercial greenhouse conditions. In each trial, two treatments were applied: (i) irrigation according to Farmer criteria without biostimulant applications and (ii) a combined treatment of RDI and the same biostimulation program, composed of Bacillus paralicheniformis and Ascophillum nodosum extracts. RDI was applied in different phenological stages in each greenhouse after the establishment until the 1st harvest in trial 1 or during the ripening and harvest period in trial 2. On average, the irrigation was reduced by 600 m3 ha−1 compared to the Farmer irrigation schedule. In both trials, biostimulation promoted an increase in fruit numbers, punctually in trial 1, leading to yield precocity, or generally in trial 2, obtaining a higher yield. Globally, WPI was increased when RDI was combined with biostimulation. This combined treatment also enhanced the root water absorption and improved the soil enzymatic activity in both greenhouses, suggesting that nutrients in the soil would become more available to plants. Thus, the combined action of biostimulation under different RDI strategies has been proved to be a useful strategy to improve agricultural sustainability.

Impact of “Dry Sowing and Wet Emergence” Water Regulation on Physiological Growth Characteristics and Water Productivity of Cotton Fields in Southern Xinjiang Province

Determining a suitable “dry sowing and wet emergence” water control program for cotton fields in the arid regions of Northwest China is of great significance in saving water resources, improving economic efficiency, and promoting sustainable development of agriculture. The objective of this study was to analyze the effects of different “dry sowing and wet emergence” water control treatments on dry matter accumulation, chlorophyll fluorescence, yield quality, and water productivity of cotton, and to determine the optimal “dry sowing and wet emergence” water control program for cotton growth in arid areas. A two-year experiment was carried out in 2021 and 2022 in mulched drip-irrigated cotton fields, with a total of 13 treatments of different seedling water quantities (2021: 67.5 mm, 90 mm, 112.5 mm; 2022: 6 mm, 10.5 mm, 15 mm) and different drip frequencies (frequencies means number of drops at seedling stage) (2021: one, two, three times; 2022: two times, four times) in the “dry sowing and wet emergence”. Results indicated a positive correlation between increased seedling water quantity and growth indexes. High seedling water quantity treatment demonstrated a 14.33% higher cotton yield than the low seedling water quantity treatment. In comparison with low-frequency treatment, the high-frequency treatment exhibited significantly larger cotton plant height, dry matter accumulation, and yield. Over two years, the average values increased by 8.69%, 16.4%, and 15.91%, respectively, with a 14.55% increase in the coefficient of photochemical quenching of the leaf blade (qP). The high frequency and larger amount of seedling water quantity treatments showed significantly higher irrigation water productivity, with increases of 39.2% and 70.2% compared to the winter irrigation control treatment. In summary, the appropriate “dry sowing wet emergence” water regulation mode (the first drip: 15 mm, the second drip: 4.5 mm, the third drip: 22.5 mm, the fourth drip: 15 mm) can ensure crop yield quality under the premise of significantly reducing the agricultural irrigation water, which can provide certain theoretical support for the green, efficient, and sustainable development of the local cotton industry.

Effects of microbial biofertilizer on growth, physio-biochemical traits, fruit yield, and water productivity of okra under drought stress

Drought poses a major challenge to global agricultural crop production, as it is considered one of the most severe abiotic stresses. Understanding the effects of exogenous microbial biofertilizer on okra [Abelmoschus esculentus (L.) Moench] under drought stress can lead to new strategies for coping with drought conditions. The objective of the study was to examine the effects of microbial biofertilizer on growth, physio-biochemical traits, fruit yield, and water productivity of okra under drought stress. A factorial pot experiment, consisting of eight biofertilizer treatments applied as a soil drench (autoclaved inoculum [control], and inoculation with arbuscular mycorrhizal fungi [AMF], phosphate-solubilizing fungi [PSF], plant growth-promoting rhizobacteria [PGPR], AMF + PSF, AMF + PGPR, PGPR + PSF, and AMF + PSF + PGPR) and three soil moisture regimes (50%, 75%, and 100% field capacity [FC]), was carried out. The results indicated that decreasing soil moisture level severely affected growth and fruit yield of okra. The application of microbial biofertilizer effectively enhanced growth, fruit yield, and physio-biochemical traits of okra under different soil moisture levels. Among the biofertilizer treatments considered, the combined application of AMF and PGPR showed remarkable efficacy in enhancing growth and productivity of okra plants under both 75% and 100% FC conditions. This co-inoculation significantly boosted shoot dry matter by 51%, root dry matter by 73%, fruit yield by 113%, and irrigation water productivity by 122% compared with plants grown without inoculation, irrespective of soil moisture levels. Furthermore, the plants treated with AMF and PGPR exhibited a noteworthy decrease in free proline accumulation by 31% compared with their non-inoculated counterparts. The results suggest that application of both AMF and PGPR biofertilizer to soil is an effective strategy to alleviate moderate drought stress. It is recommended to apply AMF and PGPR in combination to improve okra yield and water productivity under drought stress.

Water productivity in pineapple (Ananas comosus) cultivation using plastic film to reduce evaporation and percolation

Irrigated agriculture needs significant amounts of water for increasing irrigated areas to meet the increase food demand. New alternatives with high water use efficiency are needed to increase crop productivity. This work evaluates the use of plastic film mulch either as groundcover or as a percolation barrier to increase yields and water use efficiency of pineapple (Ananas comosus L.). An experiment was carried out with pineapple on a loamy sand-soil. The treatments were: (i) soil tillage with plastic film as groundcover combined with plastic film as a percolation barrier installed at 0.40 m below the soil surface; (ii) soil tillage with no groundcover combined with a percolation barrier; (iii) soil tillage with plastic film as groundcover only; (iv) soil tillage without groundcover and percolation barrier. The use of plastic mulch maintained the levels of soil water availability at least 80% during the crop cycle, while without it soil water values ranged from 15% to 70%. Groundcover with plastic mulch contributed significantly to decrease evapotranspiration and the medium crop coefficient. The plastic groundcover combined with or without the plastic percolation barrier yielded the better results of productivity, irrigation water productivity, and water footprint. The mean irrigation water productivity and water footprint were 667.12 kg mm−1 ha−1 and 109.0 L kg−1, respectively, for the use of a plastic groundcover combined with a plastic percolation barrier. The percolation barrier was more effective for saving water than for increasing yield. The use of percolation barrier with plastic contributed for saving 92–103 L kg−1 ha−1 when combined with or without ground cover.

Optimizing crop water productivity and delineating root architecture and water balance in cotton–wheat cropping system through sub-surface drip irrigation and foliar fertilization strategy in an alluvial soil

Water-intensive agricultural practices in tandem with conventional irrigation methods such as flood irrigation, has caused severe water scarcity in south-Asian Indo-Gangetic Plains (IGPs). The adoption of micro-irrigation systems (sprinker, surface drip and sub-surface drip) instead of flooding offers a great promise in water saving and enhanced fertilizer-use efficiency, and thus, improved productivity. The change in irrigation and fertilization methodology may affect the behavior of plant root growth, root architecture and, crop and water productivity. Hence, current study aimed at evaluating the influence of sub-surface drip-irrigation and fertigation strategy on crop and water productivity besides delineating root architecture and soil water balance in cotton–wheat cropping system (CWCS). Results showed that sub-surface drip irrigation (SSDI) enhanced the root system by stimulating the development of new secondary roots which actively participated in physiological responses. Root length at boll opening stage of cotton increased significantly under SSDI at 60% ETc (60% of evapo-transpiration) over other treatments. Root mass density in wheat was also significantly higher under SSDI particularly at 15–30 cm depth over surface drip and flood irrigation during 2020–21. SSDI at 100% ETc (100% of evapo-transpiration) produced statistically similar seed cotton yield, wheat grain yield and the system productivity (wheat equivalent yield) to 80% ETc. SSDI at 80% ETc (80% of evapo-transpiration), resulted in water-saving of ∼43.2% over flood irrigation in CWCS. Further, fertigation through SSDI resulted in ∼20% reduction in fertilizer needs, while achieving the yield equivalent to that of conventional fertilization. Irrigation water productivity and bio-physical water productivity of this system were ∼46.1 and 5.7% higher under 80% ETc along with F80 (80% recommended dose of nitrogen, RDN) and Mfoliar (foliar application of KNO3 & MgSO4 at flower initiation and boll development stages of cotton) over flood irrigation. Overall, SSDI at 80% of evapo-transpiration along with 80% RDN and foliar application of KNO3 & MgSO4 may prove highly beneficial to enhance the crop and water productivity in CWCS, besides saving irrigation water-use by ∼43.2% over flood irrigation in water-scarce agro-ecologies of south-Asia.

Soil water distribution and water productivity in red cabbage crop using superabsorbent polymeric hydrogels under different drip irrigation regimes

The water issue has emerged as a significant barrier to agricultural productivity, particularly in dry and semiarid agro-ecologies, particularly during the winter season. Superabsorbent hydrogels have been identified as effective tools for improving crop and water productivity in arid locations by enhancing moisture retention. The application of hydrogel to soil is commonly done as a basal application, and its effectiveness is heavily influenced by the moisture level present in the soil. Therefore, a two-year field study was carried out to study the effects of various hydrogels and their application techniques and to assess the efficacy of recently developed cross–linked hydrogels (SPG 1118 and Pusa hydrogel) on soil water distribution (both spatial and temporal), water productivity and profitability of red cabbage. The experiment consisted of two irrigation regimes [full irrigation (100% ETc) and limited irrigation (75% ETc)] assisted in main plots, with two type of hydrogels (Pusa Hydrogel and SPG 1118) and two methods of application [root dipping and soil application of hydrogels and Control with no application of hydrogel] assisted in sub plots. The field experiment was conducted using spilt plot design with three replications. The analysis of soil water distribution patterns reveals that the utilization of hydrogels has resulted in a notable increase of 3–6% in soil water content (SWC) under full irrigation conditions, as compared to plots subjected to limited water conditions. In comparison to plots without hydrogel application, the plots treated with SPG 1118 and Pusa hydrogel exhibited enhanced soil water content of 5–6% and 2–4%, respectively. Additionally, the application of hydrogels in the root dipping showed increased water availability in the crop's root zone compared to soil application in throughout the crop season. Thus, hydrogels with reduced irrigation application resulted in significantly higher crop water productivity (14%) and irrigation water productivity (8 – 14%) compared to full irrigation levels. Likewise, root dipping of SPG 1118 led in considerable improvement in CWP (12–14%) and IWP (11–12%) over no hydrogel applied plots. In relation to profitability, the adoption of full irrigation in conjunction with SPG 1118 hydrogel resulted in an 8% increase in the benefit cost ratio compared to the control plots. Hence, the use of the unique SPG 1118 hydrogel through direct application to the roots, whether under conditions of full or limited irrigation, presents an inventive approach to address the growing issues of water shortages and sustainability in countries experiencing water stress.

Irrigation water economic value and productivity: An econometric estimation for maize grain production in Italy

Climate change, characterized by rising temperatures and limited precipitation, has intensified the demand for irrigation water while simultaneously restricting its availability. This challenge poses significant risks to agricultural and food production, particularly in the Mediterranean regions where, recently, water deficits have led to substantial production losses and quality issues. Water is a critical determinant of crops' economic viability, especially for water-intensive crops, making it essential to estimate its economic relevance, especially in the absence of reliable water market prices. This study has two primary objectives: first, to evaluate the shadow price of irrigation water for maize grain at the farm level, which is defined as the value generated by the marginal unit of water consumed; and second, to analyse its heterogeneity. Leveraging a Farm Accountancy Data Network (FADN) panel of 1625 Italian farms over a decade (2010–2020), an econometric production function approach is employed. Moreover, quantile regressions reveal variations in the shadow price linked to geographical, managerial, and structural farm characteristics. Our findings underscore water’s key role in economically viable maize grain production, significantly enhancing the productivity of other inputs like fertilizers and pesticides. The average shadow price is 0.29 €/m³, with a median of 0.20 €/m³ and water total productivity accounts for one-third of maize’s average gross output. Quantile regressions uncover how factors like geographic location, altitude, farm management, irrigation water source, and farm size influence the distribution of water productivity, reflecting either efficient use or scarcity of this resource. Our estimation provides valuable insights for policymakers by offering accurate shadow price estimates for irrigation water in Italian maize grain production. Furthermore, it enhances our understanding of irrigation water’s role in the economic viability of this crop, while contributing to support evidence-based water management strategies, identifying vulnerable areas and farms and allowing for future methodological developments.