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A four-year research experiment was conducted on sandy loam soil at the University of California Kearney Agricultural Research and Extension Center in Parlier, California, to investigate the effect of midsummer deficit irrigation on alfalfa yield, irrigation water productivity (IWP), and crop water productivity (CWP). The experiment was a randomized block design with two treatments: full and deficit irrigations with three replications. Applied irrigation water was measured using flow meters and soil matric potentials were monitored using watermark soil moisture sensors. Actual evapotranspiration (ETa) values were estimated from Tule Technologies stations. The deficit irrigation treatments resulted in 454, 706, 625, and 815 mm of irrigation water savings as compared to the full irrigation treatments in 2019, 2020, 2021, and 2022, respectively. These values represent 30.3%, 40.9%, 37.0%, and 49.1% of the applied water savings. Alfalfa yield in the deficit treatments was reduced by 3.94, 2.04, 1.25, and 0.40 Mg ha−1 ; the equivalent of 18.1%, 11.1%, 7.1%, and 3.0% of the yield for the full irrigation treatment for the four years: with an average reduction of 10.7%. IWP was higher when deficit irrigation was implemented and resulted in 17.09, 16.11, 15.40, and 15.54 kg ha−1 mm−1 , in 2019, 2020, 2021, and 2022, respectively. The production function using applied irrigation water (IW, mm) was: Y(yield in Mg ha−1)=0.50×(IW)2−1,633.75×(IW)+1,338,472 and Y=−0.1137×(IW)2+233.55×(IW)−103,036 for the full and deficit irrigation treatments, respectively. CWP was 18.6, 16.4, 14.9, and 12.3 kg ha−1 mm−1 for fully irrigated treatments, and 15.2, 14.9, 14.3, and 12.6 kg ha−1 mm−1 for the deficit irrigation treatments, for 2019, 2020, 2021, and 2022, respectively. Results from this work provide growers with viable deficit irrigation practices that could be implemented during drought periods. [ABSTRACT FROM AUTHOR]

Drought has emerged as a significant abiotic stress in vegetable production. Sweet watermelon (Citrullus lanatus var. lanatus) is susceptible to drought stress (DS) and requires adequate irrigation for optimal yield and quality. The current study sought to shed light on the potential of citron watermelon as a rootstock for watermelon by studying changes in its morphological and physio-biochemical features under deficit irrigation. Crimson Tide F1 (CT) was grafted onto ten morphologically distinct citron watermelon (CW) rootstocks, with Strong Tosa (ST) commercial rootstocks and nongrafted (NG) and self-grafted (SG) Crimson Tide F1 serving as plant material. We used three irrigation (I) levels (I100, I75, and I50) while investigating multiple agronomic and biochemical properties. Increasing water stress negatively affected several plant growth parameters in watermelon. Furthermore, I50 inhibited photosynthesis and pigment content, increasing malondialdehyde (MDA), hydrogen peroxide (H2O2), leaf temperature, and membrane permeability. I50 significantly reduced stomatal conductance and leaf relative water content. Rootstocks responded differently to irrigation regimes and had varying water use efficiency (WUE). Based on the evaluated parameters, we classified ST, CW9, CW16, and CW17 as tolerant; CW4, CW6, CW8, CW11, CW13, CW14, and CW15 as moderately tolerant; and CT as highly susceptible. Combining I75 and citron rootstock will benefit targeted watermelon production and provide significant water savings for sustainable agriculture. [ABSTRACT FROM AUTHOR]

Triticale is a man-made crop produced by crossing wheat (Triticum aestivum) and rye (Secal cereal) with the aim of increasing the adaptability and potential production of its parental line (wheat) under environmental stresses and harsh conditions. Accordingly, the objectives of this study are as follow, a: compare different stability measurement methods regarding their suitability, b: identify most stable genotypes for cultivar release, and c: provide a freely available package in R programming language (named 'Stbidx') capable of exploiting all stability methods for similar studies. Accordingly, 30 triticale genotypes were evaluated for their stability and adaptability to changing environments during four consecutive years from 2016 to 2020 in different locations in Iran (one year in Zarghan, two years in Ghorveh, one year in Sanandaj) and under two different irrigation regimes (normal irrigation and water deficit stress conditions). All 30 triticale genotypes were cultivated in a randomized complete block design (RCBD) with three replications in each environment (12 environments: 6 trials in 2 conditions). Grain yield of triticale genotypes was measured and it applied to calculate all known stability indices (univariate methods) along with the meta-analysis models were evaluated in this study. Additionally, two novel techniques (Stability ID: SID and AMMI PC Value: APCV) were introduced and successfully tested for screening stable genotypes. These methods were introduced to improve and resolve the limitation of the previous stability methods. Meanwhile, heatmap analysis, as a proper data-mining technique, has been successfully applied for the first time to find stable genotypes in different environments in this study. The results clearly indicated a higher suitability of our introduced methods over previous multi-trials screening methods. Based on our methods and considering all environments, triticale genotypes ELTTCL21 (SID = 8.00; APCV = 28.12), ELTTCL25‌ (SID = 8.14; APCV = 30.02), ELTTCL30 (SID = 8.43; APCV = 17.00), ET-90-8 (SID = 14.00; APCV = 42.05), and Sanabad (SID = 10.57; APCV = 12.44) were among stable genotypes and they can be nominated as new cultivars. Additionally, for stress condition genotypes ELTTCL30 (stress: 380.6 g/m2) and ELTTCL18 (stress: 360.79 g/m2) and for normal condition genotypes ET-90-4 (normal: 849.4 g/m2) and ELTTCL20 (normal:845 g/m2) were respectively the most proper genotypes with the highest production to be considered for each condition separately. [ABSTRACT FROM AUTHOR]

Water scarcity is a major environmental stress that negatively affects the soil traits, growth of plants, and yield of crops. This research assessed the impact of vermicompost, oak tree biochar, apple tree biochar, and the combined impact of vermicompost and both biochars on the growth, water use efficiency (WUE), and yield of eggplant under conditions of limited irrigation. The main purpose of the study was deficit irrigation, which involved 3 levels of water supply: 50%, 75%, and 100% PWR (plant water requirement). The second focus was on the application of vermicompost, with two levels: 0 and 2000 gm−2, as well as biochar, with two levels: 0, 400 gm−2 of oak-tree biochar, and 400 gm−2 of apple tree biochar. The findings revealed that the combination of apple-tree biochar and vermicompost at a level of 100% PWR, delivered the most positive results in terms of plant growth and functioning. The early harvest yield was greatest when apple-tree biochar was applied alone at a level of 50% PWR. However, the total yield of the plant was highest when apple-tree biochar and vermicompost combined were applied at a level of 100% PWR. The plant's WUE reached its highest level after the combined application of apple-tree biochar and vermicompost at a level of 50% PWR. The maximum leaf levels of N, P, K, Fe, and Mg were observed when both vermicompost and apple-tree biochar were applied at a level of 100% PWR. The treatments without amendments or with vermicompost only at a level of 50% PWR exhibited the highest values of physiologically significant stress metabolites. [ABSTRACT FROM AUTHOR]

The objective of the present review article was to update the standard single (Kc) and basal (Kcb) crop coefficients published in the FAO Irrigation and Drainage Paper No. 56 (FAO56), focusing on temperate climate fruit trees (pome, stone and nut fruit trees), vines and shrubs (kiwi, hop and blue- and blackberries). Standard conditions refer to crops grown in medium to large fields, having enough fetch for non-impeding accurate use of flux measuring equipment to represent non-limiting conditions of crop evapotranspiration, ETc. Moreover, the crop needs to be managed without soil water deficit, free of pests and diseases, and must be able to reach full production under the given environmental conditions. For this purpose, more than 150 articles published over the last 25 years were reviewed. Of these, we selected 76 that refer to case studies that reporting on appropriate yield conditions, describe adequate ETc measurement and adopt the FAO reference evapotranspiration or another method closely related to it. The selection of papers to be analysed followed the same methods as the companion papers on Mediterranean woody fruit crops (Pereira et al. 2023), and on tropical and subtropical ones (Paredes et al. 2024). The literature review focused on articles that are in line with the FAO56 methodology; that is, where the grass reference evapotranspiration (ETo) was computed with the FAO Penman–Monteith ETo, the ASCE Penman–Monteith ETo equations, or other equations whose results relate well to the former. In addition, where the crop evapotranspiration (ETc) and/or crop transpiration (Tc) were determined with sufficient accuracy from field observations in crops grown under standard, well-watered conditions, i.e., under pristine (i.e., non-stress cropping conditions) or eustress (i.e., "good stress") conditions. Information collected from the selected studies included cultivar and rootstock, plant density and spacing, training system, fraction of ground cover or intercepted PAR radiation, crop height and age. Additional data were gathered on irrigation system and strategy for full or deficit irrigation. The Kc and Kcb values reported were recomputed and grouped according to the degree of ground cover, training system and plant density. Thus, the proposed tabulated standard Kc and Kcb values for initial, mid- and end-season are based on the values obtained from field observations reported in the selected papers, and on the ranges of Kc/Kcb values previously tabulated, mainly in FAO56. The currently tabulated values are updated, with the aim being their use in orchard management. They should consist of the upper limit of Kc/Kcb application, and take into account the general awareness of water scarcity and water conservation, thus helping improve the accuracy in estimating crop water requirements and optimizing irrigation scheduling. [ABSTRACT FROM AUTHOR]

To further evaluate the effect of water stress on soil respiration (RS), reveal the influencing factors of daily and seasonal RS, and systematically evaluate and compare the sensibility of different machine learning algorithms (multiple nonlinear regression [MNR], support vector machine regression [SVR], backpropagation artificial neural network [BPNN]) to estimate RS from a maize field under water stress condition, the field experiments were conducted within a maize field in Inner Mongolia, China, during the entire 2019 growing season. Various levels of deficit irrigation were conducted in the vegetative, reproductive, and mature stages. Our research indicated that soil CO2 fluxes from 100% evapotranspiration treatment (Tr1) were significantly greater than various deficit irrigation treatments (Tr2, Tr3, Tr4) during each growth stage of summer maize. The cumulative soil CO2 fluxes of Tr2, Tr3, and Tr4 decreased 24.8%, 30.3%, and 43.7% compared with Tr1, respectively. We determined that the drivers affecting the daily RS were soil temperature at 5 cm depth (TS,5) and soil surface temperature (TSF), followed by water‐filled porosity (WFPS) at 5 cm depth, but no significant correlations were observed at 25 cm depths. TS,5 and TSF also performed similar correlation with seasonal RS with R greater than 0.753 among all water treatments, followed by chlorophyll content with R greater than 0.726. During the whole growing season, the BPNN model exhibited the best predicting result, and could explain the 60%–80% and 87.8% of the variations of RS at the daily and seasonal scales, with root mean square error of 48.7–100.9 mg m−2 h−1 and 91.5 mg m−2 h−1, respectively. The SVR and MNR models could estimate the 47.9%–57% and 39.9%–52.1% of the daily RS and 81.4% and 78.6% of the seasonal RS, respectively. Overall, our study indicated the machine learning algorithms could be successfully applied to estimate RS at daily and seasonal scales from a maize field under water stress condition. [ABSTRACT FROM AUTHOR]

As competition for limited water resources in the western United States and other arid and semiarid regions intensifies, there is a need to provide alfalfa (Medicago sativa) growers with knowledge of how water‐optimizing practices impact alfalfa nutrient use. The objective of this research was to evaluate how three water management strategies, and their interactions, influence alfalfa K and P concentration, uptake, uptake efficiency, and internal use efficiency. Alfalfa cultivars, deficit irrigation, and irrigation technologies were tested at two sites in Utah during 2020–2021. A single drought‐tolerant (DT) cultivar ('Ladak II') was compared to a conventional alfalfa cultivar specific to each location. Four irrigation rates (100%, uniform reductions of 25% and 50%, and a targeted reduction of ∼50%) were nested within five pivot irrigation technologies. Few alfalfa K and P nutrient dynamics responded to the interactions of cultivar and rate or technology. Nutrient responses to the irrigation technologies were strongly associated with the technology effect on alfalfa yield such that uptake efficiency was sometimes greater with low‐elevation sprinkler technologies. The K and P responses to deficit irrigation were most pronounced at the uniform or targeted 50% irrigation rate. Alfalfa cultivar had the least impact on alfalfa K and P dynamics, and the DT cultivar never improved uptake or efficiencies. These results indicate that few adjustments in K and P management may be needed with the three water optimization approaches evaluated in this study. The most notable is that K and P fertilizer input can likely be reduced with severe deficit irrigation. Core Ideas: There is a need to identify how combinations of water optimization practices influence alfalfa nutrient management.Irrigation technology and alfalfa cultivar had minor effects on alfalfa K and P dynamics.Irrigation rate had the largest impact on K and P efficiency and use with less irrigation increasing efficiency.K and P fertilizer applications can likely be reduced under deficit irrigation strategies. [ABSTRACT FROM AUTHOR]

Determining the optimal phosphorus rates and deficit irrigation levels is key to enhancing soybean productivity in the Jawi District, Northwest Ethiopia. Soybean is a vital cash crop in Jawi District, Northwest Ethiopia, and improving its productivity is crucial for food security and community socioeconomic status. The optimal phosphorus and deficit irrigation rates in this region remain unresolved. The aim of this study was to optimize soybean productivity in this region by determining the optimal phosphorus rates and deficit irrigation levels. The experiment was conducted during irrigation seasons 2021/22 and 2022/23 using a split-plot design with an RCBD arrangement. The results showed that combining P rates of 10, 20, 30, and 40 kg ha-1 with 100% ETc. significantly increased soybean grain production. Similarly, soybean grain yield increased at P rates of 0, 10, 20, 30, and 40 kg ha-1 P with 75% ETc. The highest water productivity recorded was 0.29 kg m-3 at 50% ETc. This study suggests that combining P rates of 10, 20, 30, and 40 kg ha-1 P with 100% ETc. and P rates of 0, 10, 20, 30, and 40 kg ha-1 P with 75% ETc. could significantly enhance soybean productivity. Implementing these strategies could lead to more sustainable and efficient agricultural practices in Jawi District, thereby improving crop yields and overall profitability. [ABSTRACT FROM AUTHOR]

Efficient and affordable plant phenotyping methods are an essential response to global climatic pressures. This study demonstrates the continued potential of consumer-grade photography to capture plant phenotypic traits in turfgrass and derive new calculations. Yet the effects of image corrections on individual calculations are often unreported. Turfgrass lysimeters were photographed over 8 weeks using a custom lightbox and consumer-grade camera. Subsequent imagery was analyzed for area of cover, color metrics, and sensitivity to image corrections. Findings were compared to active spectral reflectance data and previously reported measurements of visual quality, productivity, and water use. Results confirm that Red–Green–Blue imagery effectively measures plant treatment effects. Notable correlations were observed for corrected imagery, including between yellow fractional area with human visual quality ratings (r = −0.89), dark green color index with clipping productivity (r = 0.61), and an index combination term with water use (r = −0.60). The calculation of green fractional area correlated with Normalized Difference Vegetation Index (r = 0.91), and its RED reflectance spectra (r = −0.87). A new chromatic ratio correlated with Normalized Difference Red-Edge index (r = 0.90) and its Red-Edge reflectance spectra (r = −0.74), while a new calculation correlated strongest to Near-Infrared (r = 0.90). Additionally, the combined index term significantly differentiated between the treatment effects of date, mowing height, deficit irrigation, and their interactions (p < 0.001). Sensitivity and statistical analyses of typical image file formats and corrections that included JPEG, TIFF, geometric lens distortion correction, and color correction were conducted. Findings highlight the need for more standardization in image corrections and to determine the biological relevance of the new image data calculations. [ABSTRACT FROM AUTHOR]

In the context of global warming, rising air temperatures are increasing evapotranspiration ( ET c ) in all agricultural crops, including rice, a staple food worldwide. Simultaneously, the occurrence of droughts is reducing water availability, affecting traditional irrigation methods for rice cultivation (flood irrigation). The objective of this study was to determine ET c (water use) and yield performance in rice crop under different irrigation regimes: treatments with continuous flood irrigation (CF) and irrigations with alternating wetting and drying ( A W D 5 , A W D 10 , and A W D 20 ) in an experimental area in INIA–Vista Florida. Water balance, rice physiological data, and yield were measured in the field, and local weather data and thermal and multispectral images were collected with a meteorological station and a UAV (a total of 13 flights). ET c values obtained by applying the METRICTM (Mapping Evapotranspiration at High Resolution using Internalized Calibration) energy balance model ranged from 2.4 to 8.9 mm d−1 for the AWD and CF irrigation regimes. In addition, ET c was estimated by a water balance using the AquaCrop model, previously parameterized with RGB image data and field weather data, soil, irrigation water, and crops, obtaining values between 4.3 and 7.1 mm d−1 for the AWD and CF irrigation regimes. The results indicated that AWD irrigation allows for water savings of 27 to 28%, although it entails a yield reduction of from 2 to 15%, which translates into an increase in water use efficiency (WUE) of from 18 to 36%, allowing for optimizing water use and improving irrigation management. [ABSTRACT FROM AUTHOR]

Climate change-caused water deficiency is a major threat to crop production. Different strategies such as biochar and mycorrhiza are suggested as a solution to improve water storage in the soil and increase plant tolerance to moisture deficiency. This study tested the hypothesis that under deficit irrigation conditions, the combined application of biochar and mycorrhiza can increase maize photosynthesis activity, growth, and water use efficiency (WUE). A greenhouse experiment was established to understand the effect of biochar and mycorrhizal inoculation with deficit irrigation on maize (Zea mays L.) growth, photosynthesis activity, and WUE. A factorial randomized pot experiment was designed using three biochars (B) doses from three different feedstock (DF) and three mycorrhizae (M) species (without mycorrhizae, Rhizophagus clarus and indigenous mycorrhiza), with three different irrigation (I) levels, namely, I100, I75, and I50 respectively 100%, 75%, and 50% of field capacity. For each biochar application, of 0%, 1%, and 2% rates of soil weight were applied. Maize plant dry matter (DM), photosynthesis activities, and leaf water use efficiency (WUEL) were measured. The results showed that deficit irrigation levels, such as I75 and I50 can be used for maize plant growth. Mycorrhizal inoculation increased maize plant growth between 8.2% and 8.9%, whereas biochar increased growth. In addition, mycorrhizal inoculation increased the photosynthesis activity by 9.3%. All the biochars increased maize growth and photosynthesis activity compared to the control, however, poultry manure biochar had the highest growth, photosynthesis activity, and WUE. In addition, statistically, there were no significant differences between B0*M0*I100 and B*M*I50 applications in terms of photosynthesis activity, WUE, and DM. Combined application of biochar and mycorrhiza statistically reduced irrigation water use by 50% without affecting plant DM production. [ABSTRACT FROM AUTHOR]

The objective this study was to evaluate the effects of foliar application of ascorbic acid – AsA on the production and postharvest quality of sour passion fruit under deficit irrigation strategies. The experimental design was randomised blocks, in a split-plot scheme, with plots consisting of six strategies of irrigation with water deficit, based on crop evapotranspiration – ETc (irrigation with 100% ETc during the entire cycle – S1; irrigation with 50% ETc in the different stages: vegetative – S2; flowering – S3; fruiting – S4; and successively in the vegetative/flowering stages – S5; and vegetative/fruiting stages – S6) and three concentrations of AsA (0, 88.06 and 176.12 mg/L), with three replicates and three plants per plot. Water deficit reduces the production of sour passion fruit, regardless of the phenological stage of the plants without AsA application. Irrigation with water deficit in the flowering stage (50% of crop evapotranspiration) reduces the physical and chemical quality of sour passion fruits. Ascorbic acid in applied levels was effective in alleviating the effects of water deficit on production, with emphasis on the concentration of 176.12 mg/L on the quality of sour passion fruits, in the period from 160 to 220 days after transplanting. [ABSTRACT FROM AUTHOR]

AbstractWater deficit is the most common abiotic stress and at least 75% of corn fields in Iran are exposed to drought stress during different stages of growth. humic acid (HA) and nanosilver (NS) can help mitigate abiotic stresses in plants; especially drought stress. A field experiment was conducted to study the effect of humic acid and nanosilver on the physiological traits and yield of corn during two crop years. Experimental treatments were including deficit irrigation (100%, 80%, 60% of crop water requirement (CWR)) and nanosilver (0 (NS0), 60 (NS60), 80 (NS80) and 100 (NS100) microliters/liter/ha) and humic acid (control (HA0), 500 (HA500) and 1000 (HA1000) g/ha). The highest amount of chlorophyll a, b and total in 100% CWR+NS60+HA1000 was obtained. The highest amount of proline in 60% CWR + NS60 +HA1000 as well as treatment NS0 +HA1000 were observed. In all irrigation levels, the application of NS100 has reduced chlorophyll a and total. The yield components were affected by HA and nanosilver foliar spraying. The highest grain yield was observed in 100% CWR with the application of NS60 +HA500 at the rate of 10,582 kg/ha. In conditions of 100% CWR, nanosilver concentrations had a positive effect on plant growth and yield, and with increasing stress, high concentrations of nanosilver had a negative effect on growth and yield, but with the combined application of nanosilver and HA, the effect of drought stress decreased, which indicates the positive effect of HA in improving plant growth and yield. [ABSTRACT FROM AUTHOR]

Super high-density (SHD) planting systems are very efficient in terms of production and water use. In these orchards, water-saving irrigation strategies are used precisely to keep the best sustainability compared to traditional orchards. With agro-climatic and eco-physiological parameter monitoring, the SHD planting system has become even more efficient. SHD orchards, however, could also be more so affected by other pests and diseases than traditional systems, but field responses are still unknown when olive trees are grown in SHD groves. The goal of this two-year field research was to investigate the seasonal changes of the phytosanitary status of 'Arbosana' grown in an SHD orchard under both regulated deficit (RDI) and full irrigation regimes (FI). This study investigated the influence of the two different irrigation regimes on the infections of three olive tree key diseases: cercosporiosis (Pseudocercospora cladosporioides), cycloconium (Fusicladium oleagineum), and olive knot (Pseudomonas savastanoi pv. savastanoi). RDI significantly reduced the severity of cercosporiosis in 2020 compared to FI but not in 2021. Cycloconium was observed only as a latent infection during the two studied years and olive knot was not influenced by irrigation but only by weather conditions. These findings suggest that irrigation management can play a key role in controlling cercosporiosis effectively in SHD olive orchards, but also that weather conditions have an even higher impact on the tree key diseases. [ABSTRACT FROM AUTHOR]

This work was conducted over three-year monitoring seasons of three almond cultivars (Guara, Marta, and Lauranne) subjected to deficit irrigation in combination with cover crops in a Mediterranean semiarid area (SW, Spain). Four water–soil treatments were evaluated based on the conjunction of two irrigation strategies: fully irrigated (FI), covering 100% of the ETC, and regulated deficit irrigation (RDI), with two soil-management systems: bare soil (BS) and cover crop based on a mixture of vetch (Vicia sativa L.) and oat (Avena sativa L.) (CC). Throughout the study period in trees, the yield, the stem water potential (Ψstem), leaf nutrient content (N, P, K, Ca, Mg, Na, Fe, Zn, Mn, and Cu) in soils, organic carbon, microbial biomass, fluoresceine diacetate, and enzymatic activities (dehydrogenase, protease, β-glucosidase, and alkaline phosphatase) were determined. In addition, the dry matter and carbon fixation by plant covers were evaluated. For Guara and Lauranne, yield reductions (22 and 26%, respectively) were found for water-stressed (RDI-CC) plots with respect to non-stressed combination (FI-CC) plots, contrasting with cv. Marta, without a significant impact on productivity in all combinations. That is, the RDI (~3.000 m3 ha−1) strategy enabled acceptable productivity, offering promising possibilities for cultivation performance under water-scarcity scenarios. Important differences in Ψstem could be observed and ascribed to irrigation strategies, especially for Guara and Lauranne, but without significant effects due to the soil-management systems applied. No differences were observed in the tree nutritional status due to the presence or absence of CC; however, its presence increased the fixation of atmospheric carbon, which was not the case under BS conditions. Additionally, CC significantly fostered the microbial processes and enzymatic activities, particularly in upper soil layers (0–10 cm) and with plenty of water supply in FI-CC plots and to a lesser extent in RDI-CC plots, which could encourage prominent aspects for soil quality and health restoration. Thus, the cover crop is congruent with RDI to facilitate soil functionality and water savings in a changing climate, contributing to resilient farming systems in the Mediterranean environment. [ABSTRACT FROM AUTHOR]

Context: Preharvest granulation of Imperial mandarins is a significant problem for the Australian market. Causes of, and solutions for, this physiological disorder are poorly understood despite decades of research worldwide. Aims: This research aimed to find management practices for growers to reduce granulation. Methods: A 5-year on-farm trial in central Queensland, Australia, compared standard versus deficit irrigation and five rates of winter nitrogen application. Key results: Reducing water (irrigation plus rainfall) in the 16–18 weeks following flowering reduced granulation in 3 of 5 years. Granulation increases with ratio of total water received to evapotranspiration, particularly in low crop load years. Higher nitrogen applications reduced granulation in 4 of 5 years, although treatment means were only significantly different at α = 0.05 in 1 year. Granulation increased with stronger early spring flush growth in a low crop load year and with later spring flush growth in one of two high crop load years. The deficit irrigation treatment had less spring flush growth and higher fruit set than the control in all years. Higher nitrogen treatments had more flush growth in high crop load years and less in low crop load years. Our data suggests competition between flush growth and fruit development for mineral resources and/or carbohydrates is a factor in the variability of granulation from fruit to fruit, but crop load is more important. Conclusions: The three key strategies to minimise granulation are to maintain high crop loads, reduce irrigation after flowering, and apply sufficient nitrogen in winter. Implications: This research will improve fruit quality for the consumer and financial returns to growers. Granulation, a physiological disorder in which citrus fruit are white, dry and tasteless, is a significant problem for Imperial mandarins in Australia. We discovered that excessive irrigation and insufficient nitrogen fertilisation are important causes of granulation and three key strategies to minimise granulation are to maintain high crop loads, reduce irrigation after flowering, and apply sufficient nitrogen in winter. This research will improve fruit quality for the consumer and financial returns to growers. [ABSTRACT FROM AUTHOR]

Remote sensing is now a valued solution for more accurately budgeting water supply by identifying spectral and spatial information. A study was put in place in a Vitis vinifera L. cv. Cabernet-Sauvignon vineyard in the San Joaquin Valley, CA, USA, where a variable rate automated irrigation system was installed to irrigate vines with twelve different water regimes in four randomized replicates, totaling 48 experimental zones. The purpose of this experimental design was to create variability in grapevine water status, in order to produce a robust dataset for modeling purposes. Throughout the growing season, spectral data within these zones was gathered using a Near InfraRed (NIR) - Short Wavelength Infrared (SWIR) hyperspectral camera (900 to 1700 nm) mounted on an Unmanned Aircraft Vehicle (UAV). Given the high water-absorption in this spectral domain, this sensor was deployed to assess grapevine stem water potential, Ψstem, a standard reference for water status assessment in plants, from pure grapevine pixels in hyperspectral images. The Ψstem was acquired simultaneously in the field from bunch closure to harvest and modeled via machine-learning methods using the remotely sensed NIR-SWIR data as predictors in regression and classification modes (classes consisted of physiologically different water stress levels). Hyperspectral images were converted to bottom of atmosphere reflectance using standard panels on the ground and through the Quick Atmospheric Correction Method (QUAC) and the results were compared. The best models used data obtained with standard panels on the ground and allowed predicting Ψstem values with an R2 of 0.54 and an RMSE of 0.11 MPa as estimated in cross-validation, and the best classification reached an accuracy of 74%. This project aims to develop new methods for precisely monitoring and managing irrigation in vineyards while providing useful information about plant physiology response to deficit irrigation. [ABSTRACT FROM AUTHOR]

Maize is widely growth in arid and semi-arid region where, drought is common and a limiting factor for crop production. Potassium plays a key role in enhancing plant growth under drought condition. The objective of this study is to determine the effect of K fertilization with and without NP on maize growth grown in sandy loam soil under adequate and deficit irrigation conditions. The following treatments were investigated in pot experiment: (1) control with no fertilizer application (C); (2) 128 kg N + 328 kg P2O5 ha-1 (NPK0); (3) 128 kg N + 328 kg P2O5 ha-1 + 152.5 kg K2O ha1 (NPK1); (4) 128 kg N + 328 kg P2O5 ha-1 + 305 kg K2O ha-1 (NPK2); and 128 kg N + 328 kg P2O5 ha-1 + 457.5 kg K2O ha-1 (NPK3). Treatments were investigated under adequate and deficit soil moisture content. Each pot filled with 3.5 kg air-dry soil and seeded with maize and pots were watered according to the treatments. The results indicated that plant growth and nutrient uptake were significantly reduced under water stress condition. The application of NP increased plant growth and nutrient uptake and further were increased with K application. K application also enhanced plant tolerance to deficit soil moisture condition. In addition, K enhanced nutrient uptake and leaf chlorophyll content. Based on the results, it can be concluded that application of NP for maize was not adequate to achieve the highest plant growth, unless it is combined with K application. In addition, K application enhances plant tolerance to water stress. [ABSTRACT FROM AUTHOR]

The increase in crop yield can be primarily attributed to the combined effect of genetic advancements, as well as increased contributions from nitrogen (N) and water. The accumulation of dry matter plays a crucial role in determining grain yield in winter wheat. The current study aimed to better understand the source‐sink dynamics, analyse the dry matter transport (DMT) before and after anthesis and calculate its ratio to grain yield. In this experiment, eight main cultivars of winter wheat that have been widely cultivated in Shaanxi Province since the 1940s were selected as planting material. Field examinations were conducted using three levels of both irrigation and N. The yield‐related parameters, dry matter accumulation, dry matter distribution, DMT and DMT efficiency were measured. The results showed that irrigation prolonged the time of dry matter accumulation, and the application of N fertiliser increased the rate of dry matter accumulation. The analysis of the dynamic characteristic parameters of dry matter in winter wheat showed that irrigation and N had a significant impact on rate of dry matter accumulation. The proportion of stems, leaves and spikes of new varieties increased significantly (p < 0.05), which increased by 56.67%–69.7%, 13.26%–18.07% and 15.78%–28.26%, respectively, with the varietal improvement. The DMT efficiency increased with varietal improvement and also with increased irrigation and N application. The response of irrigation treatment to DMT and dry matter was more significant. In addition, the irrigation treatment had a higher effect on the DMT efficiency of vegetative organs after anthesis. The logistic equation analysis revealed that water stress accelerated the fulfilment of maximum daily temperature (Tmax), while both the maximum growth rate (Gmax) and dry matter weight (Wmax) decreased as water stress increased. There was a positive linear relationship between dry matter accumulation after anthesis and grain yield. The structural equation model showed that varieties, N application and irrigation had significant positive effects on DMT, post‐anthesis dry matter and grain yield, while irrigation had significant negative effects on DMT efficiency. The accumulation of dry matter in winter wheat after anthesis showed a significant increase with the succession of varieties. The combination of moderate deficit irrigation and fertilisation improved transportation and dry matter accumulation after anthesis in winter wheat, thereby enhancing its production capacity. [ABSTRACT FROM AUTHOR]

Soybeans are a crucial major food source in human and animal nutrition due to their high fat and protein content. This study investigated the effects of different irrigation methods on yield and yield components of second-crop soybeans under deficit irrigation conditions. The study aimed to determine the crop evapotranspiration, water productivity (WP), and irrigation water productivity (IWP) of the second crop soybean. The study followed a split plot random block experimental design with three replications. The main treatments of the study were subsurface drip irrigation (SDI), drip irrigation (DI), and furrow irrigation (FI) with four different water application levels (100%, 75%, 50%, and 25%) serving as subtreatments. Crop evapotranspiration (ETc) ranged between 236–482 mm for DI, 185–410 mm for SDI, and 275–562 mm for FI during 2018 and 2019. The yields for DI, SDI, and FI varied between 3,340–4,030 kg ha−1 , 3,250−3,780 kg ha−1 , and 2,800–3,680 kg ha−1 during 2018 and 2019, respectively. The effect of water deficit applications on yield was statistically significant at p<0.05 level. It was determined that the yield components of soybeans were negatively affected by deficit irrigation treatments, but the effect of different irrigation methods was not significant. There was no statistical difference between the treatment with 25% deficit irrigation and the full irrigation comparing the yield and yield components of the study. Moreover, WP and IWP values increased as the amount of irrigation water decreased in all irrigation methods. Thus, a 25% deficit is recommended as an alternative to full irrigation in the Mediterranean Basin when water resources are scarce. [ABSTRACT FROM AUTHOR]

This study aimed to investigate the evaporation (E) and transpiration (T) components of evapotranspiration (ETc), and the growth parameters of curly lettuce (Lactuca sativa L. cv. Caipira) grown under different irrigation treatments. The study was conducted in a Mediterranean-type plastic greenhouse located in Antalya, Türkiye, in the fall and spring growing seasons of 2020 and 2021, respectively. To assess the impact of water stress on ETc and its components, three different irrigation water levels [ I100 for full irrigation treatment (100%), I66 for 66% (I100×0.66), and I33 for 33% (I100×0.33)] were selected. Planted and unplanted pots were used to measure ETc and E independently. The values obtained from these measurements were used as inputs to calculate the evaporation that occurred in the soil under the crop canopy and plant transpiration. In the present study, T was determined indirectly from the difference of measured evapotranspiration and evaporation and estimated with the modified Hernandez-Suarez model (Te). The modified model for the different irrigation treatments showed high Te estimation performance. Evaporation from the soil in the planted pots (Es) was calculated by considering the canopy cover and soil water content. The study revealed that water stress significantly affected lettuce plant height, root length, cover percentage, leaf area index (LAI), number of leaves, fresh and dry head weights, and root weights (p<0.01). The study also investigated the relationship between Es/ETc , and LAI using an exponential method and established a strong nonlinear relationship in all irrigation treatments (R2>0.90). The modified model developed for different irrigation treatments in Mediterranean-type greenhouses can be used to predict lettuce ETc values with greater precision and to better understand the partitioning of ETc into its constituent components. [ABSTRACT FROM AUTHOR]

The use of carbonaceous materials such as biochar has been considered an innovative solution in agriculture, especially to mitigate dry events caused by climate change. Biochar can improve water holding capacity, physical and chemical properties of soil, and increase the productivity of agricultural systems. However, underlying physiological mechanisms remain poorly understood. Mineral supplementation with potassium nitrate (KNO3) via foliar application is another promising strategy in agricultural management under irrigation deficit. Thus, we investigated the combined effects of biochar and foliar application of KNO3 on growth, yield, and physiology of tomato plants under different irrigation regimes. Results did not indicate a synergistic effect of biochar and foliar application of KNO3. Biochar application alleviated tomato plant stress under deficit irrigation, with plants showing better functioning of photosynthetic apparatus, higher yield, and better fruit quality, as well as increased water use efficiency. Coffee husk biochar (K-rich feedstock) fully met the tomato plant's demand for K and partially met the demand for some other elements (P, Mg, Fe, Zn, Mn, and Cu). Although positive effects of KNO3 application was verified for some physiological and fruit quality components, overall, foliar application of KNO3 did not improve tomato yield. It is concluded that biochar soil amendment can be a promising practice to increase yield and quality of tomato fruits under deficit irrigation. Therefore, biochar-based fertilizer can be an alternative K source that also provides stable carbon to soil and helps to mitigate stress caused by prolonged drought. [ABSTRACT FROM AUTHOR]

The biological and organic fertilizers application under drought stress can reduce the adverse effects of this global issue and improve plant growth and development parameters. Therefore, this study was conducted in two crop years of 2020-2021 and 2021-2022 in the climatic conditions of Chalus city, Iran. The split-factorial experiment was conducted in the form of a basic randomized complete block design with 3 replications. The main factor included irrigation deficit at three levels (100, 80, and 60% of water requirement) and the secondary factors included biological fertilizer (control, mycorrhizal fungus, and Enterobacter) and organic fertilizer (no use, 16, and 24 tons per hectare) in a factorial manner. The results of the mean comparison showed that the highest seed yield was observed in the second year under 100% irrigation and application of 24 t/h of organic fertilizer and mycorrhiza at the rate of 126.1 g/m2; Subsequently, theco application of 80% water requirement and 24 t/h of organic fertilizer and Enterobacter treatments in the second year caused the highest amount of 124.3 g/m2. Generally, the 60% water requirement reduced grain yield compared to other water requirements levels. According to the results of this study, the organic and biological fertilization under drought stress conditions can significantly improve the quantitative and qualitative yield of mung bean. Therefore, it is recommended that the organic and biological fertilizers can be applied in drylands to mitigate drought stress conditions, and improve the growth, yield and quality of mung beans. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

CITRUS is one of the most important fruit crops grown in the worldwide, especially in Mediterranean countries. Deficit irrigation (DI) is a proposed strategy many years ago to overcome the scarcity of water, especially in arid and semiarid regions. The vegetative growth, enzymatic activities, proline and phenolic content, fruit yield and quality in response to deficit irrigation levels (T1 (irrigation every 15 days as a control), T2 (irrigation every 20 days), T3 (irrigation every 25 days), and T4 (irrigation every 30 days), were evaluated. The results showed that the P, K, proline, phenols, vitamin C, SSC contents, and catalase and peroxidase activities were increased by T2 and T3. While the N content, fruit yield, weight, peel thickness, juice volume, and transpiration rate were increased by T1 and T2 compared to T3 and T4. The fruit yield, weight, and physical properties were not negatively affected by light and medium deficit irrigation (T2 and T3), which positively affected enzymatic activities, proline and phenol contents, and chemical fruit properties (SSC and Vitamin C). [ABSTRACT FROM AUTHOR]

BACKGROUND AND OBJECTIVES: The study explored the relationship between irrigation practices, water availability, and soil fertility in relation to crop yield. The investigation analyzed three distinct irrigation scenarios, namely full irrigation, deficit irrigation, and rain fed agriculture. The primary objective of the study was to evaluate the correlation between irrigation practices and soil fertility. To achieve this, the study incorporated different soil fertility levels, with high levels representing unlimited fertility for both full and deficit irrigation, and low levels corresponding to rain fed conditions. This design is primarily used to isolate the effects of irrigation practices on crop yields under a variety of fertility scenarios. The study also looks into how to achieve sustainable water management in the agricultural sector. METHODS: Aqua-crop, a computerized model, was utilized mimic real-life crop harvests. The aqua crop model was used to simulate crop yield in response to water availability. The calibration of the model involved utilizing data on various crop growth parameters, including soil fertility, crop canopy cover, evapotranspiration, soil water movement, crop yield and harvest index percentage. This innovative study utilizes aqua-crop to analyze the impact of irrigation methods on crop yields under controlled settings, effectively isolating irrigation influences from soil discrepancies. This approach is well-suited for studying sustainable water management strategies in agriculture, a pressing concern in light of worldwide water water scarcity. FINDINGS: Aqua-crop simulations revealed that consistent irrigation with a full irrigation system and high efficiency (70 percent) resulted in high yields. The simulated yields (8.48 to 10.04 tons per hectare) were significantly higher than farmers' actual yields (3.86 to 4.74 tons per hectare). Discrepancies between farmer irrigation methods and the model's assumption of uniform water application are the probable cause of the variation, underscoring the significance of considering real-world intricacies in the interpretation of model outcomes. The observed yield differences despite similar irrigation systems indicate the potential impact of unaccounted for factors such as soil type variations and real-world farmer practices (e.g., fertilization). Nevertheless, a substantial R-squared value of 0.85 suggests a robust association between simulated and observed yields, suggesting that aqua-crop can be valuable in comprehending overall irrigation-yield connections. Emphasis is placed on considering real-world complexities to achieve optimal crop yield. Aqua-crop simulations analyzed the correlation between irrigation and water use efficiency. Although full irrigation resulted in the highest simulated yields, deficit irrigation enhanced evapotranspiration water productivity. This seemingly contradictory finding can be explained by diminishing returns: deficit irrigation may result in slightly lower yields but higher water efficiency, highlighting the importance of considering both yield and water use efficiency when making long-term irrigation decisions. has highlighted the disparity between projected and actual crop yields, underscoring the significance of incorporating practical factors into the simulation of irrigation techniques. This finding holds particular relevance in areas where water resources are limited. CONCLUSION: The Food Agriculture Organization's aqua-crop is a useful tool for farmers who have limited access to water. Aqua-crop is a computer-based model that replicates the growth of crops in different irrigation scenarios. It provides farmers with the opportunity to explore the correlation between water usage and crop yield. By doing so, they can determine the most effective irrigation strategies that optimize harvest while minimizing water consumption. This aspect holds particular significance in regions facing water scarcity. [ABSTRACT FROM AUTHOR]

The extreme weather and the deteriorating water environment have exacerbated the crisis of freshwater resource insufficiency. Many studies have shown that salty water could replace freshwater to partly meet the water demand of plants. To study the effects of early-stage drought hardening and late-stage salt stress on tomatoes (Solanum lycopersicum L.), we conducted a 2-year pot experiment. Based on the multi-objective demands of high yield, high quality, and water saving, yield indicators, quality indicators, and a water-saving indicator were selected as evaluation indicators. Three irrigation levels (W1: 85% field capacity (FC), W2: 70% FC, W3: 55% FC) and three salinity levels (S2: 2 g/L, S4: 4 g/L, S6: 6 g/L) were set as nine treatments. In addition, a control treatment (CK: W1, 0 g/L) was added. Each treatment was evaluated and scored by principal component analysis. The results for 2022 and 2023 found the highest scores for CK, W2S2, W3S2 and CK, W2S4, W2S2, respectively. Based on response surface methodology, we constructed composite models of multi-objective demands, whose results indicated that 66–72% FC and 2 g/L salinity were considered the appropriate water–salt combinations for practical production. This paper will be beneficial for maintaining high yield and high quality in tomato production using salty water irrigation. [ABSTRACT FROM AUTHOR]

Copyright of Misr Journal of Agricultural Engineering is the property of Egyptian National Agricultural Library (ENAL) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Misr Journal of Agricultural Engineering is the property of Egyptian National Agricultural Library (ENAL) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Jute, known as the 'Golden Fibre,' has been an intrinsic part of the Indian economy for centuries. India is the leading producer and exporter of jute, contributing to almost 70% of global production. However, the productivity of jute crops in India is often hampered by dry spells and erratic rainfall patterns. This article aims to explore the crucial role of dry spells on jute productivity and discuss ways to mitigate their negative impact through optimization of deficit irrigation water usages. An open-field experiment was carried out on jute cultivation under varying soil depletion of available moisture (DASM) and estimated crop water requirement (ETc) levels. The results of the study revealed that application of irrigation at '50% DASM with 75% ETc' or '75% DASM with 100% ETc' is beneficial to the crop during the pre-monsoon season for olitorius jute in alluvial soils of sub-tropical climate. The available soil-water regime at 100 to 50% soil water depletion produced the best fibre yield and water productivity. A yield increase of 23–44% was achieved with irrigation scheduling in comparison to the rainfed condition. Soil moisture, biomass, and canopy cover were all accurately simulated by the AquaCrop model. The study recommends deficit irrigation water usage as a method to reduce yield gaps and mitigate dry spells. [ABSTRACT FROM AUTHOR]

The present investigation assesses a variety of parameters available in the literature to model gold–water interfaces using molecular dynamics simulations. The study elucidates the challenges of characterizing the solid–liquid affinity of highly hydrophilic gold–water interfaces via wettability. As an alternative, the local pairwise interaction energy was used to describe the solid–liquid affinity of flat and curved surfaces, where for the latter, the calculation of a contact angle becomes virtually impossible. Regarding the heat transfer properties of different interface models (flat and curved), partly conclusive trends were observed between the total pairwise interaction energy and the thermal boundary conductance. It was observed that the solid surface structure, interfacial force field type, and force field parameters created a characteristic bias in the interfacial water molecules (liquid structuring). Consequently, a study of the liquid depletion layer provided better insight into the interfacial heat transfer among different interfaces. By computing the density depletion length, which describes the deficit or surplus of energy carries (water molecules) near the interface, a proper characterization of the thermal boundary conductance was obtained for the different gold–water interfaces. It was observed that the interfacial heat transfer is favored when the water molecules organize in cluster-like structures near the interface, by a surplus of water molecules at the interface, i.e., lower density depletion length, and by the closeness of water to the solid atoms. [ABSTRACT FROM AUTHOR]

Water scarcity is an extreme global concern due to changing climate and rapid population growth. Worldwide, freshwater sources are depleting and there is a need to implement water-conserving approaches in water-limited or arid areas for sustainable crop production. Therefore, this study aimed to investigate the impact of deficit irrigation on cucumber plant physiology, growth, and fruit yield traits grown under greenhouse conditions. The experiment was conducted in a complete randomized design with four water regimes, 100%, 80%, 60%, and 40% crop water requirement (ETc). Results showed that the highest plant leaf chlorophyll contents (43.2 µmol m-2), plant biomass (12.43 g), plant height (172.39 cm), number of leaves (19.85), fruit yield (2.49 kg), and total soluble solids (3.73 °Brix) were in plants irrigated at 100% level. In comparison, the lowest plant height (115.73 cm), number of leaves (15.77) and fruit yield (1.81 kg) were recorded at 40% irrigation. Results revealed that reduced irrigation regimes up to 80% or 60% have no significant inhibitory effects on cucumber agro-morphological traits. However, 40% of irrigation levels showed significantly reduced plant morphological and fruit yield traits. Overall, the result demonstrated that regulated deficit irrigation can significantly conserve water without negatively impacting cucumber yield.

High-density olive groves, despite their interesting production potential, have several limitations, including their high fruit load and irrigation requirements. This study aimed to evaluate the effects of fruit load and deficit irrigation on oil yield, fruit quality, and olive chemical composition in a high-density olive grove (cv Sikitita). Our main hypothesis was that primary metabolism, as influenced by crop load and stress, could modify the accumulation of different phenolic classes. Different fruit loads were generated through flower thinning (66%, 50%, 33%, 0%), and two deficit irrigation treatments (−60%, −75%) were compared to the well-watered control (920 m3/ha). Thinning treatments had a limited effect on oil yield; on the other hand, deficit irrigation caused considerably less oil accumulation in the fruit on all sampling dates. Thinning 66% and deficit irrigation 75% were considered with the control for untargeted metabolomic analysis, including three sampling dates. A total of 233 distinct phenolic compounds were annotated. Multivariate HCA results indicated that harvest time had an impact on the phenolic profile of olive fruits, obtaining two separated clusters that grouped t1 and t2 together and apart from t3, which clustered independently. Regarding agronomic techniques, they played a differential role in the phenolic profile (supervised OPLS-DA). Fruit load mostly affected flavonoid glycosides. In contrast, the phenolic response to deficit irrigation was more heterogeneous, with phenolic acids (35%), flavonoids (25%), LMW, and other phenols (25%).

In order to investigate the effect of nitrogen and zinc sulfate fertilizers on the quantitative and qualitative yield of forage maize under low irrigation stress, this experiment was conducted as a split-factorial randomized complete block design with 4 replications in Ilam province during the two crop years of 2019 and 2020 was implemented. Three levels of irrigation including full irrigation (control or 90% of field capacity), irrigation based on 75% of field capacity (25% soil moisture discharge) and irrigation based on 50% of field capacity (50% soil moisture discharge) in the main plots Done. Factorial wetting of three levels of nitrogen from urea source, including zero (control), 150 and 300 kg ha-1 urea fertilizer; and foliar application of zinc sulfate at 3 levels of 0, 2 and 4 per thousand as the second factor in random was randomized. The results of combined analysis of variance showed that the interaction of year deficit irrigation stress×foliar application of zinc sulfate and the interaction of year deficit irrigation stress×nitrogen on total fresh yield were significant. The interaction of year deficit irrigation stress, year. Nitrogen fertilizer, year and foliar application of zinc sulfate, low irrigation stress×foliar application of zinc sulfate and the interaction of low irrigation stress×nitrogen fertilizer on the concentration of digestible dry matter were significant. Wet forage yield in full irrigation and consumption of 150 kg urea per hectare was 77728 kg.ha-1. Wet forage yield was obtained in complete irrigation treatment and consumption of 4 per thousand zinc sulfate in the amount of 78163 kg.ha-1. At irrigation levels based on the presence of 75% and 50% of field capacity, consumption of 4 per thousand zinc sulfate increased this index, so that in the mentioned treatments wet yield was obtained at 67460 and 49855 kg.ha-1, respectively. Irrigation treatment based on 50% of field capacity, application of 300 kg of urea fertilizer and 2 per thousand zinc sulfate resulted in grain protein content of 8.6%. Due to the lack of significant differences between treatments 2 and 4 per thousand zinc sulfate in different levels of nitrogen fertilizer, so the use of 300 kg of urea fertilizer per hectare and 2 per thousand zinc sulfate has good performance and economic justification and as the superior compound was selected to counteract the harmful effects of dehydration.

Abstract Background To optimize irrigation water use and productivity, understanding the interactions between plants, irrigation techniques, and fertilization practices is crucial. Therefore, the experiment aims to assess the effectiveness of two application methods of potassium humate combined with chelated zinc under partial root-zone drip irrigation techniques on maize nutrient uptake, yield, and irrigation water use efficiency across two irrigation levels. Methods Open-field experiments were carried out in two summer seasons of 2021 and 2022 under alternate and fixed partial root-zone drip irrigation techniques to investigate their impacts at two irrigation levels and applied foliar and soil applications of potassium humate or chelated zinc in a sole and combinations on maize. Results Deficit irrigation significantly increased hydrogen peroxide levels and decreased proline, antioxidant enzymes, carbohydrate, chlorophyll (a + b), and nutrient uptake in both partial root-zone techniques. The implementation of combined soil application of potassium humate and chelated zinc under drought conditions on maize led to varying impacts on antioxidant enzymes and nutritional status, depending on the type of partial root-zone technique. Meanwhile, the results showed that fixed partial root-zone irrigation diminished the negative effects of drought stress by enhancing phosphorus uptake (53.8%), potassium uptake (59.2%), proline (74.4%) and catalase (75%); compared to the control. These enhancements may contribute to improving the defense system of maize plants in such conditions. On the other hand, the same previous treatments under alternate partial root zone modified the defense mechanism of plants and improved the contents of peroxidase, superoxide dismutase, and the uptake of magnesium, zinc, and iron by 81.3%, 82.3%, 85.1%, 56.9%, and 80.2%, respectively. Conclusions Adopting 75% of the irrigation requirements and treating maize plants with the soil application of 3 g l−1 potassium humate combined with 1.25 kg ha−1 chelated zinc under alternate partial root-zone technique, resulted in the maximum root length, leaf water content, chlorophyll content, yield, and irrigation water use efficiency.

Abstract Lessons learned from past experiences push for an alternate way of crop production. In India, adopting high density planting system (HDPS) to boost cotton yield is becoming a growing trend. HDPS has recently been considered a replacement for the current Indian production system. It is also suitable for mechanical harvesting, which reducing labour costs, increasing input use efficiency, timely harvesting timely, maintaining cotton quality, and offering the potential to increase productivity and profitability. This technology has become widespread in globally cotton growing regions. Water management is critical for the success of high density cotton planting. Due to the problem of freshwater availability, more crops should be produced per drop of water. In the high-density planting system, optimum water application is essential to control excessive vegetative growth and improve the translocation of photoassimilates to reproductive organs. Deficit irrigation is a tool to save water without compromising yield. At the same time, it consumes less water than the normal evapotranspiration of crops. This review comprehensively documents the importance of growing cotton under a high-density planting system with deficit irrigation. Based on the current research and combined with cotton production reality, this review discusses the application and future development of deficit irrigation, which may provide theoretical guidance for the sustainable advancement of cotton planting systems.

The crop water stress index (CWSI) is an important technique for determining stress levels in the plant and directing irrigation management techniques. To determine the CWSI for sunflower, a pot-based research trial was carried out in the research field of the Department of Soil and Water Engineering, PAU, Ludhiana (India) during the summer of 2023. The sensor-based irrigation scheduling was carried out on the basis of the depletion of total available soil moisture (TASM). The drip irrigation treatments consist of I1 (full irrigation), I2 (20% depletion of TASM), and I3 (40% depletion of TASM). The results revealed that the highest amount of water applied under I1 was recorded at 484.4 mm, while I2 (387.5 mm) and I3 (290.7 mm) during the growing season of sunflower. The results revealed that for kernel diameter and seed weight, I1 and I2 were statistically non-significant to each other while I1 and I3 were statistically significant to each other. The highest water productivity recorded for I2, followed by I3. The overall findings revealed that an average CWSI value of 0.85 for the sunflower crop falls within the range of lower and upper baselines. The response of physico-chemical properties of sunflower seeds showed a high correlation with the draught condition. HIGHLIGHTS Investigated crop water stress (CWSI) of sunflower under varying soil moisture depletion.; To develop lower and upper limits of baselines for fully irrigated and under stressed conditions.; To analyse physico-chemical changes of sunflower seed and oil.; To develop sensor-based irrigation scheduling for sunflower crops under deficit condition.; To analyse the water productivity of sunflower under various irrigation regimes.;

We investigated, under field conditions and during four years (2018-2021) the effects of five irrigation levels (T1: 100% of crop water requirement; T2: 80% of T1; T3: 60% of T1; T4: 40% of T1, and T5: 0% of T1 - rainfed) in interaction with three planting densities (PD1: 54 900, PD2: 64 900, and PD3 75 200 plants/ha) on the yield, yield components and water use efficiency (WUE) of maize in Srem, Serbia. The results indicate a large year-to-year variability, mainly due to the total amount and distribution of rainfall. Water regime and PD interacted significantly. Irrigation increased grain yield 28, 34, 30 and 18% for treatments T1, T2, T3 and T4, respectively, compared to the T5; and significantly influenced the yield components. Planting density had significantly lower effects on grain yield compared to irrigation (+1.4-1.8%). WUE is maximised (3.436 kg/m3) at T4 under 75 200 plants/ha. Grain yield and WUE increased significantly with increasing PD, while the number of grains per ear and the weight of 1 000 grains decreased with increasing PD. In conclusion, limited irrigation at T2 under PD2 may be a viable method to maximise production efficiency and maize yield under the environmental conditions of this study and at sites with similar soil and climatic conditions.

Background: While water availability is important for quality at harvest, it also continues to influence the quality of pomegranates during storage. Reducing the amount of irrigation, in addition to water saving has different effects on bioactive compounds of pomegranate during storage time. This study was conducted to determine the influence of irrigation level on fruit quality changes during storage period of two commercial Iranian pomegranate cultivars ('Shishecap' and 'Malas-Yazdi'). Sustained deficit irrigation (SDI) was applied to plants that received 75% (moderate stress) or 50% (severe stress) of their normal water requirement. A control group received 100% of their water requirement. Results: At harvest time and during storage period, fruit weight loss and some biochemical traits such as fruit total soluble solids (TSS), titratable acidity (TA), pH, total phenolic compounds (TPC), total anthocyanins content (TAC), antioxidant activity and vitamin C were measured in pomegranate fruits. Also, the quantity of the produced product was also measured at the time of harvesting. Results indicated that control fruits exhibited more weight loss than those produced under water deficit during the storage period in both years. According to results, fruit TSS, TAC, and antioxidant activity significantly increased during storage period but fruit TA and vitamin C significantly decreased throughout storage period. Also, reduction in irrigation level resulted in a decline in the yield. Conclusions: This study revealed a crucial link between irrigation level and the quality of pomegranate fruits, despite a reduction in the yield. This included affecting weight loss and the content of bioactive compounds, both at harvest and during storage. [ABSTRACT FROM AUTHOR]

This study aims to develop an Artificial Neural Network (ANN) modeling to be trained to forecast the effects of different irrigation water levels and fertilizer doses on the hay yield and some quality traits of herbal parts of Sorghum × Sudan grass hybrid (Sorghum sudanense vs. Sorghum bicolor). The ANN model was developed on the limited field experiments implemented in Bilecik, Turkey, for 2 years in 2021 and 2022. Experiments were conducted in split-plot design with three replications. In the study, three irrigation levels (I100, I60, and I30) were placed in the main parcels, and four fertilizer levels (N0, N50, N100 and N150 kg ha−1) were placed in the sub-parcels. Irrigations were made in three critical periods according to the amount of cumulative evaporation occurring in the Class A Pan. The results showed that irrigation and fertilization are important in terms of yield and quality characteristics. The yield increased depending on the irrigation and fertilization dose, and the highest value was obtained from the I100 × N150 interaction (28.10 t ha−1). The highest protein yield was determined from the I60 × N150 (2.37 t ha−1) interaction, and the Relative Feed Value (RFV) value was determined from the I30 × N150 (92.17) interaction. Irrigation Water Use Efficiency (IWUE) and Water Use Efficiency (WUE) values increased with decreasing irrigation amount, and the highest IWUE was determined from I30 and the highest WUE was determined from I60 irrigation subjects. According to the field experiments and ANN model, the I80 irrigation with 100 kg ha−1 nitrogen doses would suit the feed yield and quality of Sorghum × Sudan grass hybrid. [ABSTRACT FROM AUTHOR]

Water scarcity, combined with low soil fertility, constitutes one of the main limiting factors in crop productivity in semi-arid regions. However, nutritional supplementation techniques with nitrogen (N) and molybdenum (Mo) can lead to positive enhancements in the production of these crops. The objective was to evaluate the effect of increasing doses of N in the presence and/or absence of Mo on the activity of antioxidant enzymes and the productive increase of forage sorghum subjected to water deficit in the semi-arid region. The experiment was conducted in the field using a randomized block design, with four replications, in a 5 × 2 × 3 factorial scheme, comprising five doses of N (urea): 0, 50, 100, 150, and 300 kg ha−1, two doses of Mo (sodium molybdate): 0 and 160 g ha−1, and three production cycles. The highest yields of green mass (GM) (47.98 Mg ha−1), dry mass (DM) (19.66 Mg ha−1), water use efficiency (WUE) (5.57 kg/m³), and N use efficiency (NUE) (0.26 kg2/g) occurred at the highest N dosage (300 kg ha−1 N). The highest contents and extraction of total N, Mo, chloride (Cl), and potassium (K) were found in regrowth 2 and at the highest N dose (300 kg ha−1). The interaction of N and Mo resulted in higher catalase (CAT) enzyme activity. The meteorological conditions during the cycles strongly influenced the nutrient contents and extraction. The results of the study provide support for producers to use N and Mo fertilization strategies to improve crop productivity, even under water deficit conditions. [ABSTRACT FROM AUTHOR]

Given the scarcity of arable land and water resources in semi-arid regions, it becomes imperative to achieve maximum yield and early maturity for winter grains. In this regard, the present research was conducted to synchronize grain and shoot maturity in high-yielding barley (cv. Behrokh) by reducing nitrogen and deficit irrigation. The experimental factors included three levels of nitrogen (50, 75, and 100% plant nitrogen requirement; PNR) and three levels of irrigation (full irrigation, cutoff irrigation in the milk stage, and dough stage). Results showed that cutoff irrigation and nitrogen fertilizer caused early ripening. The interactions of irrigation and nitrogen were significant for the number of grains/spike, grain yield, straw yield, aboveground biomass, and protein yield. Grain yield in cutoff irrigation in the dough stage plus reducing 25% PNR was similar to full irrigation plus 100% PNR. In full and cutoff irrigation in the dough stage, reducing 25% PNR did not cause a significant change in straw yield. Cutoff irrigation in the dough and milk stages did not cause a significant difference in the grain protein content. In general, it is concluded that to maintain grain, straw yield, and protein quality, it is more appropriate to use 150 kg/ha of nitrogen in the conditions of cutoff irrigation in the dough stage, which could reduce the cost of fertilizer and water in addition to early ripening of the crop and minimize the environmental consequences of consuming these inputs. Early harvesting of barley also helps to prevent summer crops from encountering late-season chilling. [ABSTRACT FROM AUTHOR]

With the increasing world population, global warming, and climate change, water scarcity significantly limits water use in crop production. Therefore, timely and accurate determination of water stress is very important for the correct and effective management of existing water resources and minimizing harmful effects on crop production. Two years of experiments were conducted in the water-limited region in Türkiye to investigate the possible use of the Crop Water Stress Index (CWSI) as a remote sensing technology in sugar beet irrigation scheduling. Four different Irrigation levels (I50: 50% deficit, I75: 25% deficit, I100: full irrigation, and I125: 25% excess irrigation) were applied to sugar beet by drip irrigation system. The amount of applied irrigation water and crop evapotranspiration varied between 238-540 and 350-580 mm in 2021, and between 324- 807 and 502-829 mm in 2022. In both years, the highest beed yields were obtained from I100 treatments (83 and 130 t ha-1) and the lowest from I50 treatments (66.7 and 67.4 t ha-1). Water Productivity (WP) and Irrigation Water Productivity (IWP) in both years decreased significantly by excessive irrigation. CWSI values ranged between 0.16-0.98 in 2021 and between 0.02-0.71 in 2022. CWSI was significantly related to yield and Leaf Area Index (LAI). According to the results, CWSI could be used successfully in sugar beet irrigation scheduling and yield estimation. [ABSTRACT FROM AUTHOR]

Secondary growth in garlic depreciates its visual aspect and thereby renders the crop unviable for trade. Therefore, farmers commonly reduce fertilization and impose drought and oxidative stress caused by high-dose pesticides to reduce secondary growth in garlic plants. However, these procedures can be considered adverse, unhealthy, and environmentally inappropriate. To remedy this scenario, we investigated whether spraying growth inhibitors would prevent secondary growth in garlic plants. First, we evaluated the effects of abscisic acid, trinexapac-ethyl, chlormequat chloride, and paclobutrazol treatments on garlic plants grown in polyethylene tanks (250 m3). We then analyzed the effects of deficit irrigation combined with the application of trinexapac-ethyl (sprayed two or three times) and the application of trinexapac-ethyl, chlormequat chloride, or paclobutrazol alone (each sprayed two or three times) on garlic plants grown in the field, comparing them with the effects of deficit irrigation (control treatment) alone. The in-field experiment was replicated with the following treatments: control (deficit irrigation) and trinexapac-ethyl (sprayed two or three times) treatments. We analyzed the physiological, biometric, and production parameters affecting secondary growth in garlic plants. We observed that trinexapac-ethyl could efficiently regulate secondary growth without causing physiological disturbances in garlic plants. Our results provide valuable information that will contribute to the development of a sustainable technique to replace the current practices used by farmers to prevent secondary growth in garlic plants. [ABSTRACT FROM AUTHOR]

The combined application of biochar and fertilizer has become increasingly popular for improving soil quality and crop productivity. However, the reported research results regarding the effects of biochar on soil properties and crop productivity have contradictory findings, indicating the requirement for further scientific research. Therefore, this study aimed to investigate the effects of a combined application of water hyacinth biochar (WHB) and NPS fertilizer on soil physicochemical properties and wheat yield under deficit irrigation conditions in acidic silty loam soil in Ethiopia. Four different biochar rates (0, 5, 10, and 20 t ha−1), three fertilizer rates (0, 100, and 200 kg NPS ha−1), and two irrigation regimes (50 and 100% of crop requirement) were evaluated to assess soil properties and wheat yields. The results showed that biochar amendment significantly reduced soil bulk density by 15.1–16.7%, and improved soil porosity by 6.8–8.6% and moisture content by 10.3–20.2%. Additionally, the combined application of biochar and fertilizer improved soil pH (0.26–0.87 units), NH4+–N (73.7–144%), NO3−–N (131–637%), and available phosphorus (85.8–427%), compared to the application of fertilizer alone. As a result, wheat dry biomass and grain yield increased by 260 and 173%, respectively. Furthermore, the combined application of WHB and fertilizer resulted in a comparable wheat dry biomass and grain yield even with a 50% reduction of irrigation water. Therefore, WHB has a significant potential to improve soil physicochemical properties and wheat yield when it is applied in combination with fertilizer, and it can reduce the water requirement for wheat production. [ABSTRACT FROM AUTHOR]

Water-saving irrigation is of extraordinary importance for tomato production in semi-arid areas of northwest China. For this purpose, we conducted a two-season trial in a solar greenhouse of two tomato genotypes named '181' and 'Mao Fen 802' and cultivated with substrate, under four irrigation regimes, i.e., well-watered (WW), low (LWD, 80% WW), moderate (MWD, 60% WW) and high (HWD, 40% WW) water deficit. The substrate water content of WW treatment was 75%θf to 90%θf (where θf is the field capacity). The study results showed that the single fruit weight and yield of tomato were significantly declined with an increasing water deficit degree. Compared to WW treatment, the fruit weight and yield were decreased about 34.45% and 20.35% for '181' and 'Mao Fen 802' under HWD treatment, respectively. Conversely, water deficit treatment led to an obvious promotion of WUE and showed an upward trend as the water deficit level increased. In addition, compared to WW treatment, the water deficit significantly decreased the total flavonoids of the '181' tomato by 24.4–93.1%, whereas there was no significant impact on that of 'Mao Fen 802'. Nonetheless, different individual polyphenols were increased by suitable deficit irrigation for two tomato cultivars. Gallic acid, 3,4-dihydroxybenzoic acid, and naringin of '181'tomato were increased by 128.4–195.2%, 8.6–43.7%, and 31–73-fold, respectively, under water deficit compared to WW treatment. Further, under water deficit treatment, p-coumaric acid, benzoic acid, and 3,4-dihydroxybenzoic acid of 'Mao Fen 802' were increased by 36.2–49.2%, 59.1–189.7%, and 36.3–106.4% compared to WW treatment. As the main carotenoid component, the lycopene content of tomato fruit exhibited a significant rise of 7.84–20.02% and 20.55–32.13% for '181' and 'Mao Fen 802' under three degrees of water deficit compared to WW treatment. Linear regression showed a significantly positive relationship between irrigation amounts and yield, and total polyphenols, whereas there was a significantly negative relationship between irrigation amounts and WUE, and total carotenoids. Based on correlation and PCA, WW and LWD, and MWD and HWD, were gathered together for '181', while LWD, MWD, and HWD, were gathered, and only WW scattered for 'Mao Fen 802', along the PC1 direction. It was proposed that 'Mao Fen 802' was more sensitive to water deficit than the '181' tomato. In conclusion, water deficit is conductive to water-saving cultivation of the greenhouse tomato and the tomato genotypes, and water deficit level is a key factor necessary for consideration. [ABSTRACT FROM AUTHOR]

Almond cultivation has a long-standing tradition on the island of Majorca, traditionally practiced under rainfed conditions. Currently, new plantations are established with irrigation; however, due to present conditions and the impacts of climate change, water availability is limited. The Government of the Balearic Islands permits a maximum water supply of 3000 m3 ha−1 per year for almond cultivation. In this study, a 6-year field trial was conducted to investigate the adaptation of fourteen almond cultivars obtained from different research centers under deficit irrigation practices in the soil and climatic conditions of Majorca Island. The cultivars had a significant effect on trunk cross-sectional area TCSA, cumulative almond in-shell yield, cumulative kernel yield, yield efficiency, and shelling percentage. The 'Marta' and 'Tarraco' cultivars exhibited the highest TCSA values. Regarding cumulative almond in-shell yield, 'Glorieta' and 'Constantí' produced the highest yields, whereas the lowest yields were observed in 'Mardía' and 'Tarraco'. In terms of shelling percentage, 'Ferragnès' exhibited the highest value. Kernel quality parameters were cultivar-specific. Additionally, oleic acid content was strongly negatively correlated with linoleic acid content. All cultivars exhibited an unsaturated fatty acid content exceeding 90%, with 'Masbovera' showing the highest value. [ABSTRACT FROM AUTHOR]

The optimization of plant density plays a crucial role in cotton production, and deficit irrigation, as a water-saving measure, has been widely adopted in arid regions. However, regulatory mechanisms governing nitrogen absorption, transportation, and nitrogen use efficiency (NUE) in cotton under deficit irrigation and high plant density remain unclear. To clarify the mechanisms of N uptake and NUE of cotton, the main plots were subjected to three irrigation amounts based on field capacity (Fc): (315 [W1, 0.5 Fc], 405 [W2, 0.75 Fc, farmers' irrigation practice], and 495 mm [W3, 1.0 Fc]). Subplots were planted and applied at three densities: (13.5 [M1], 18.0 [M2, farmers' planting practice], and 22.5 [M3] plants m−2). The results revealed that under low-irrigation conditions, the cotton yield was 5.1% lower than that under the farmer's irrigation practice. In all plant densities and years, the nitrogen uptake of cotton increased significantly with the increase in irrigation. However, excessive irrigation resulted in nitrogen accumulation and migration, mainly concentrated in the vegetative organs of cotton, which reduced the NUE by 9.2% compared with that under farmers' irrigation practice. Concerning the interaction between irrigation and plant density, under low irrigation, the nitrogen uptake of high-density planting was higher, and the yield of seed cotton was only 2.9% lower than that of the control (the interaction effect of farmers' irrigation × plant density), but the NUE was increased by 10.9%. Notably, with the increase in irrigation amount, the soil nitrate nitrogen at the 0–40 cm soil layer decreased, and high irrigation amounts would lead to the transfer of soil nitrate nitrogen to deep soil. With the increase in plant density, the rate of nitrogen uptake and the amount of nitrogen uptake increased, which significantly reduced the soil nitrate nitrogen content. In conclusion, deficit irrigation and high plant density can improve cotton yield and NUE. We anticipate that these findings will facilitate optimized agricultural management in areas with limited water. [ABSTRACT FROM AUTHOR]

High-density olive groves, despite their interesting production potential, have several limitations, including their high fruit load and irrigation requirements. This study aimed to evaluate the effects of fruit load and deficit irrigation on oil yield, fruit quality, and olive chemical composition in a high-density olive grove (cv Sikitita). Our main hypothesis was that primary metabolism, as influenced by crop load and stress, could modify the accumulation of different phenolic classes. Different fruit loads were generated through flower thinning (66%, 50%, 33%, 0%), and two deficit irrigation treatments (−60%, −75%) were compared to the well-watered control (920 m3/ha). Thinning treatments had a limited effect on oil yield; on the other hand, deficit irrigation caused considerably less oil accumulation in the fruit on all sampling dates. Thinning 66% and deficit irrigation 75% were considered with the control for untargeted metabolomic analysis, including three sampling dates. A total of 233 distinct phenolic compounds were annotated. Multivariate HCA results indicated that harvest time had an impact on the phenolic profile of olive fruits, obtaining two separated clusters that grouped t1 and t2 together and apart from t3, which clustered independently. Regarding agronomic techniques, they played a differential role in the phenolic profile (supervised OPLS-DA). Fruit load mostly affected flavonoid glycosides. In contrast, the phenolic response to deficit irrigation was more heterogeneous, with phenolic acids (35%), flavonoids (25%), LMW, and other phenols (25%). [ABSTRACT FROM AUTHOR]