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International audience; Maize production is essential for global food security and represents a major supply in several value chains. However, the projected effects of climate change are likely to decrease drastically water availability for crops in many regions, affecting yield. AgriVoltaics (AV) systems are an innovative solution that may improve maize resilience in water-scarce regions mainly by protecting plants from excessive radiation and by reducing irrigation needs. However, shade from panels may also affect crop development and production. This study addresses the interplay between radiation transmission, crop development and irrigation needs of maize cropping in field conditions, by the description of crop development dynamics, distinguishing between fixed and dynamic panels. We showed that maize crop responded to both independent and combined stresses (shade and water deficit), with a significant decrease in leaf area index, total dry matter and grain yield. Concerning water use, we showed the potential of AV to reduce irrigation inputs (by up to 19-47% compared to unshaded plots) via reduced soil water depletion and reference evapotranspiration. The crop development was impacted by shade by increasing phyllochron and causing a generalized delay in phenology. At a finer temporal scale, we concluded that maize leaves react to shade by reducing stomatal conductance, net assimilation of CO2 and leaf temperature in a correlated way to radiation, opening the possibility to use this behavior to optimize water use and shading strategies. The spatial heterogeneities of radiation in fixed AV systems, compared to dynamic AV systems, were identified as a second-order effect at the plot level on leaf area index and phyllochron, compared to the effect of radiation reduction. Moreover, dynamic AV showed their ability to reduce the spatial heterogeneities in soil water depletion, showing the importance of controlled shade strategies in AV systems concerning water use.

Deficit irrigation is critical to global food production, particularly in arid and semi-arid regions with low precipitation. Given water shortage has threatened agricultural sustainability under the dry-land farming system in China, there is an urgent need to develop effective water-saving technologies. We carried out a field study under two cultivation techniques: (1) the ridge and furrow cultivation model (R); and (2) the conventional flat farming model (F), and three simulated precipitation levels (1, 275 mm; 2, 200 mm; 3, 125 mm) with two deficit irrigation levels (150 and 75 mm). We demonstrated that under the ridge furrow (R) model, rainfall harvesting planting under 150 mm deficit irrigation combined with 200 mm simulated precipitation can considerably increase net photosynthesis rate (Pn), quantum yield of PSII (ΦPSII), electron transport rate (ETR), performance index of photosynthetic PSII (Fv/Fm′), and transformation energy potential of PSII (Fv/Fo). In addition, during the jointing, anthesis and grain-filling stages, the grain and biomass yield in the R model are 18.9 and 11.1% higher than those in the flat cultivation model, respectively, primarily due to improved soil water contents. The winter wheat fluorescence parameters were significantly positively associated with the photosynthesis, biomass and wheat production. The result suggests that the R cultivation model with irrigation of 150 mm and simulated precipitation of 200 mm is an effective planting method for enhancing Pn, biomass, wheat production, and chlorophyll fluorescence parameters in dry-land farming areas.

Declining water availability is pressing rice growers to adopt water-saving irrigation practices such as aerobic rice to maintain profitability per megalitre (ML) of water input. Irrigators require well-defined irrigation thresholds to initiate irrigation to maximise water productivity. Such thresholds do not exist for temperate rice regions. Adopting a strategy that has been reported to succeed in non-temperate environments may fail in temperate climates, and therefore, needs investigation. This study aimed to investigate, in a temperate Australian environment, the effect of increasing soil moisture deficit during the rice vegetative period on crop physiological development, grain yield and water productivity. The study was conducted in a commercial farm using a randomised complete block design in the 2020/21 and 2021/22 growing seasons. Automated gravity surface irrigation technologies were adopted to enable high-frequency irrigation. Extending soil moisture deficit beyond 15 kPa was found to significantly delay panicle initiation by at least 13–14 days, exposing rice to cold temperatures in Year 1 during the cold-sensitive early pollen microspore period. This reduced yield by up to 55% (4.5 t/ha) compared to the 15 kPa treatment that was not impacted by cold sterility. In the absence of cold sterility, irrigated water productivity and total water productivity ranged between 1.02 and 1.61 t/ML, and 0.84 and 0.93 t/ML, respectively. The highest yields (8.1 and 7.5 t/ha) were achieved irrigating at a soil tension of 15 kPa in growing seasons 2020/21 and 2021/22. This research demonstrates that sound water productivity can be achieved with aerobic rice cultivation in temperate climates, providing cold temperatures during early pollen microspore are avoided. The quantification of the delay in crop development caused by increasing soil moisture deficit provides rice farmers greater confidence in determining the irrigation strategy and timing of pre-emergent irrigation in regions at risk of cold sterility. However, due to the high labour demand associated with aerobic rice, the adoption of aerobic rice at a commercial scale in this Australian environment is unlikely without adopting automated irrigation technology.

Fil: Zubillaga, María Fany. Universidad Nacional de Rio Negro. CIT Rio Negro. Río Negro, Argentina. Fil: Martínez, Roberto Simón. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Valle Inferio. Río Negro, Argentina. Fil: Martínez, Roberto Simón. Universidad Nacional de Rio Negro. CIT Rio Negro. Río Negro, Argentina. Fil: Camina, Ricardo. Universidad Nacional del Sur. Bahía Blanca. Buenos Aires, Argentina. Fil: Orioli, Gustavo Adolfo. Universidad Nacional del Sur. Bahía Blanca. Buenos Aires, Argentina. Fil: Orioli, Gustavo Adolfo. Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET). Ciudad Autónoma de Buenos Aires. Buenos Aires, Argentina. Fil: Failla, Mauricio. Proyecto Patagonia Noreste. Balneario El Cóndor. Río Negro, Argentina. Fil: Alder, Maite. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Valle Inferio. Río Negro, Argentina. Fil: Barrio, Daniel Alejandro. Universidad Nacional de Rio Negro. CIT Rio Negro. Río Negro, Argentina. Fil: Barrio, Daniel Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET). Ciudad Autónoma de Buenos Aires. Buenos Aires, Argentina. Introduction. The production potential of grain amaranth has recently been demonstrated in northeastern Patagonia, Argentina. This crop under irrigation and in a temperate semi-arid climate showed an adequate development of the plants in their different phenological stages with high economic performance. Objectives. This study explored the response of Amaranthus cruentus cv Mexicano to different irrigation frequencies in the lower valley of Río Negro river, Patagonia, Argentina. Method. The experimental design was of three blocks with randomized treatments (subplots), each one corresponding to a different irrigation frequency. The first six irrigations were performed every 7 days for all the treatments, to ensure the establishment of the crop. Then the following treatments were applied: irrigation every 7 days (FI), every 14 days (FII), and every 21 days (FIII). The following biometric variables and their components were measured: height of plant, number of leaves, biomass and economic yield. Results. The results suggest that the optimum irrigation frequency was FII (14 days), resulting in an adequate plant stand at panicle initiation and allows a proper development of plant with optimal biological and economical yields and the highest efficiency of water use (4.02 kg·m-3). Conclusions. The contributions of this study demonstrated the production potential of A. cruentus crop in the lower valley of the Río Negro river under irrigation, representing the southernmost study on irrigation frequency made for this grain crop in the world. A management of irrigation water of 7 days for the establishment of the crop and then with a frequency of 14 days showed the highest yield and the best water use efficiency Introducción. El potencial productivo del amaranto en grano ha sido demostrado recientemente en el noreste de la Patagonia, Argentina. Este cultivo bajo riego y en un clima templado semiárido mostró un adecuado desarrollo de las plantas en sus diferentes estados fenológicos con un alto rendimiento económico. Objetivos. Este estudio exploró la respuesta de Amaranthus cruentus cv Mexicano a diferentes frecuencias de riego en el valle inferior del río Negro, Patagonia, Argentina. Método. El diseño experimental fue de tres bloques con tratamientos al azar (subparcelas), cada uno correspondiente a una frecuencia de riego diferente. Los primeros seis riegos se realizaron cada 7 días para todos los tratamientos, para asegurar el establecimiento del cultivo. Luego se aplicaron los siguientes tratamientos: riego cada 7 días (FI), cada 14 días (FII) y cada 21 días (FIII). Se midieron las siguientes variables biométricas y sus componentes: altura de planta, número de hojas, biomasa y rendimiento económico. Resultados. Los resultados sugieren que la frecuencia de riego óptima fue la FII (14 días), que da lugar a un adecuado stand de la planta en el momento de la iniciación de la panoja y permite un correcto desarrollo de la planta con óptimos rendimientos biológicos y económicos y la mayor eficiencia en el uso del agua (4,02 kg-m-3). Conclusiones. Los aportes de este estudio demostraron el potencial productivo del cultivo de A. cruentus en el valle inferior del río Negro bajo riego, representando el estudio más austral sobre frecuencia de riego realizado para este cultivo de grano en el mundo. Un manejo del agua de riego de 7 días para el establecimiento del cultivo y luego con una frecuencia de 14 días mostró el mayor rendimiento y la mejor eficiencia en el uso del agua.

Increased water scarcity necessitates the implementation of water-conserving irrigation management practices to sustain crop production, especially in water-limited areas. Field experiments were conducted to evaluate midday leaf water potential (LWP) of bell pepper (Capsicum annuum L. var. annuum) irrigated differentially using surface drip (DI) and subsurface drip irrigation (SDI) systems during 2016 and 2017 growing seasons in the eastern Mediterranean environmental conditions. The treatments considered were deficit irrigations (I-50, I-75), regulated deficit irrigation (RDI), partial root-zone drying (PRD50) and full irrigation (I-100) under DI and SDI systems. The experimental design was completely randomized in a split-plot system with four replicates per treatment. Deficit irrigation treatments of I-75 and I-50 received 75% and 50% I-100, respectively; RDI was supplied with 50% I-100 during vegetative growth stage until flowering, then received 100% of crop water requirement; PRD50 plots received 50% I-100. Bell pepper plant water status was estimated by LWP. Higher LWP values were determined in I-100 for two drip systems than the I-75, I-50, and PRD50; LWP correlated significantly (P < 0.01) and negatively with fresh pepper yield, DM yield, leaf area index (LAI), and mean soil water content and all these relations are best described with the curvilinear equations. In conclusion, bell pepper should be irrigated at mean LWP values between -0.89 and -0.95 MPa without any yield reduction. It is also concluded that RDI and I-75 treatments appear to be good alternatives to I-100 for sustainable bell pepper production under the Mediterranean environmental conditions.

Regulated deficit irrigation in super-high-density (SHD) olive orchards is a well-known strategy to save water and control plant vigor, without decreasing fruit or oil yield. As there is controversial information about its influence on virgin olive oil quality, a trial was conducted in five SHD olive orchards of Arbequina cultivar in different locations of central, east, north and northeast Spain under full irrigation (FI) and regulated deficit irrigation (RDI) treatments. RDI applied during phase II of fruit growing (40% of total needs) saves more than 20% of water on average, without reductions in olive fruit or extra virgin olive oil (EVOO) yield. No threshold of 3.5 MPa of stem water potential was crossed in any case. RDI modified sterols and the fatty acid profile of EVOOs but not phenols, quality parameters, or the sensory profile. Latitude, altitude, and yearly rainfall have a big impact on some compounds such as campesterol, oleuropein, or margaroleic or linolenic acids. This research was partially funded by the Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), Ministerio de Ciencia e Innovación (MCIN), grants RTA2012-00059-C02-01 y C02-02.

The profitable production of cabbage is primarily constrained by improper irrigation and fertilizer management. A field experiment comprising of four drip irrigation levels (0%, 25%, 50%, and 75% of ASMD) and four fertilizer levels (RDF @ 150:60:90, STCR50 @ 215:115:150, STCR55 @ 258:148:203 and farmers’ conventional dose @ 92:240:240 kg NPK ha−1) was conducted on cabbage in an inceptisol during rabi season in two consecutive years. The results revealed that drip irrigation at 0% ASMD with STCR55-based fertilization produced the tallest plant (27.39 cm), greatest leaf area per plant (4208 cm2), the highest LAI (1.75), and the greatest length of head (18.86 cm), diameter of head (17.78 cm), fresh weight of head (951 g), and head yield (73.9 t ha−1). Conversely, the lowest plant height (21.34 cm), leaf area per plant (3433 cm2), LAI (1.43), length of head (15.12 cm), diameter of head (14.33 cm), fresh weight of head (722 g), and head yield (51.4 t ha−1) were produced by drip irrigation at 75% ASMD and the farmers’ conventional dose. Irrigation water at 323.44 mm through the drip system was found to be optimal for water-yield production function. Deficit irrigation at 75% ASMD with STCR55-based fertilizers recorded the highest CWP (50.13 kg m−3). The crop yield response factor (Ky) for the total crop growing period was found to be 1.19 (R2 = 0.91). The maximum FUE (0.21 t kg−1 of nutrient applied) was obtained with drip irrigation at 0% ASMD with general RDF. The moisture component (volumetric moisture content) was introduced in TYE to enhance its predictability using machine learning algorithms. Based on higher yield, CWP, FUE, and economic analysis, the imposition of drip irrigation at 0% ASMD coupled with STCR55-based fertilization may be recommended to the cabbage growers of the Indo-Gangetic inceptisols of West Bengal, India or, those in similar agro-climatic condition.

BACKGROUND Based on the interrelationship among photosynthesis (Pn), water consumption and drought resistance physiology under water changes, this study aimed to explore whether easily measured Pn could be used to reflect the physiological state of winter wheat and soil moisture. The study was a greenhouse pot experiment, with three growth periods and four gradients of moisture. RESULTS The instantaneous water use efficiency of wheat improved significantly under short-term regulated deficit irrigation conditions. The photosynthetic parameters could effectively reflect the level of soil moisture (receiver operating characteristic curve analysis, area under the curve = 0.683-0.988). There was a significant correlation between Pn and yield under drought and rewatering (P 0.745, P 0.600, P

In this study, we assessed the efficiency of a deficit irrigation program (DIP) on groundnut (Arachis hypogaea L.) yield and economic profits. The DIP was designed to combine frequency and volume of irrigation to develop an appropriate irrigation water management (IWM) strategy for groundnut. Two field experiments were conducted at the Agricultural College and Research Institute, Madurai, Tamil Nadu, India, with a bunch variety of groundnut, VRI 2, under a randomized block design (RBD) with three replications. The treatments included DIP in combination with a foliar application of pink-pigmented facultative methylotrophic bacteria (PPFM). The irrigation frequencies adopted for the first set of treatments were high frequency (5/5), medium frequency (7/5), and lower frequency (7/7) starting from 14 days after sowing (DAS). The effects of early water stress on groundnut pod yield and water use efficiency were investigated in a second experiment by starting irrigation at 21 DAS. The number of irrigation frequencies and irrigation volume was fixed to develop an easily readable irrigation chart for end-users. The number of irrigation frequencies was fixed as three, and the volume of irrigation was fixed as a depth of 3 cm. In the first experiment, a mini mobile pumping unit was used for scheduling irrigation frequencies; in the second experiment, the surface drip method was used. In both experiments, we also assessed the effects of foliar application of PPFM, widely used as a growth stimulant for several crops, especially under drought conditions. Overall, we observed that DIP led to up to 25.6% water saving compared to surface irrigation. Use of the DIP at the medium frequency with PPFM spray had a significantly positive influence on water use efficiency (WUE) and irrigation water use efficiency (IWUE) compared to conventional drip irrigation (CDI). Compared to surface irrigation (SI), DIP had a positive impact on growth parameters, yield attributes, and economic profitability with a higher benefit-cost ratio. Additionally, there were only minor differences between deficit irrigation (DI) results starting from 21 DAS and 14 DAS. Irrespective of the irrigation techniques, PPFM application had a positive effect on the yield attributes and WUE. Our results indicated that DI at a medium frequency (7/5) with PPFM spray, starting from 21 DAS under drip fertigation, is the best irrigation management innovation (IMI) strategy for optimum utilization of irrigation water without significant reduction in pod yield. This management had a positive influence on WUE and IWUE of summer groundnut in sandy clay loam soil. However, the exact scheduling of the irrigation may differ in different environments as well as soil types. Nevertheless, we propose that the application and further optimization of the DIP devised in this study would help the farmers attain a similar yield using a lower amount of irrigation water and lead to significant economic profits for the farmers.

Faced with severe global shortage of water and soil resources, studies on the integrated effect of water and nitrogen on tomato cultivation are urgently needed for sustainable agriculture. Two successive greenhouse experiments with three irrigation regimes (1, 2/3, 1/3 full irrigation) and four nitrogen levels (1, 2/3, 1/3, 0 nitrogen) were conducted; plant growth, fruit yield and quality were surveyed; and comprehensive quality and net profit were evaluated. The results show that water and nitrogen deficit decreased plant growth, evapotranspiration and yield while increasing production efficiency and fruit comprehensive quality. An antagonism effect from water and nitrogen application was found in tomato yield, organic acid, solids acid ratio, vitamin C and lycopene, whereas synergistic impact was observed in total soluble solids content. Water deficit had more significant effect on tomato yield and fruit quality parameters compared with that of nitrogen deficiency. Synthesizing the perspectives of yield, quality, resource productivity, market price index and profits, 1/3 full irrigation and 2/3 full nitrogen was the best strategy and could be recommended to farmers as an effective guidance for tomato production.

The frequency of irrigation and deficit irrigation management are drawing attention because water resources are becoming limited year by year, especially in the last decade. Besides, the rate and application time of P fertilization gained more importance just after the researchers found out it is more effective than N-fertilizing for alfalfa cultivation. This study aimed to determine the effects of different irrigation managements (seasonal deficit, intervals of 5, 7, and 9 days), phosphorus application season (autumn and spring), and the rate of P fertilizer (0, 30, 60, 90 kg ha-1) on the yield and forage quality of alfalfa. The experiment was conducted in the 2019-2020 years, which was the 3rd and the 4th years of alfalfa respectively, under semi-arid Mediterranean conditions. The stand height and fiber content (NDF) were higher in the autumn application. However, forage contained more nitrogen in the spring application. A higher amount of water (800 mm) with higher irrigation frequency (5 days – I5d) caused a reduction in yield due to water excess. The yield was the highest (21.34 t ha-1) and the forage quality was better in 448 mm water application with 9 days intervals (I9d). Seasonal deficit water management caused a significant loss in yield and quality. Nevertheless, 18.04 t ha-1 dry matter yield with 24.05 % CP content was recorded at seasonal deficit water management. P fertilization increased the yield and forage quality. The yield was the highest (20.23 t ha-1) at the rate of 90 kg ha-1 P fertilizer, but yield and forage quality characteristics were similar between 30, 60, and 90 kg ha-1 P. The results showed that P fertilization could be done in both autumn and spring at the rate of 30 kg ha-1 and 448 mm water could be applied at 9 days intervals for fulfilling performance under semi-arid Mediterranean conditions. When water resources are very scarce, the seasonal water deficit should be applied, especially in late summer.

Ensuring food security with limited water resources in arid countries requires urgent development of innovative water-saving strategies. This study aimed to investigate the effects of various tillage and mulching practices on soil water storage (SWS), growth, production, irrigation water use efficiency (IWUE), and water productivity (WP) of wheat under full (FL) and limited (LM) irrigation regimes in a typical arid country. The tillage practices comprised the conventional tillage (CT) and reduced tillage (RT), each with five mulching treatments (MT), including non-mulched (NM), plastic film mulch (PFM), wheat straw mulch (WSM), palm residues mulch (PRM), and a mixture of wheat straw and palm residues at 50/50 ratio (MM). Results showed higher SWS at different measured time points in CT than RT at 20–40 cm, 40–60 cm, and 0–60 cm soil depth under FL regime, and at 40–60 cm under LM regime, while the opposite was observed at 0–20 cm and 20–40 cm soil depth under LM regime. SWS at different soil depths under MT, in most cases, followed the order of PFM > PRM ≈ MM > WSM > NM under FL, and PFM ≈ PRM > MM > WSM > NM under LM regimes. No significant differences were observed for traits related to growth between CT and RT, but RT increased the traits related to yield, IWUE, and WP by 5.9–11.6% than did CT. PFM and PRM or PRM and MM showed the highest values for traits related to growth or yield, IWUE, and WP, respectively. No significant differences in all traits between CT and RT under the FL regime were observed, however, RT increased all traits by 8.0–18.8% than did CT under the LM regime. The yield response factor (Ky) based on plant dry weight (KyPDW) and grain yield (KyGY) under RT was acceptable for four MT, while KyGY under CT was acceptable only for PRM, as the Ky values in these treatments were

Adoption of water-saving cultivation strategy for cereal crops benefits development of the sustainable agriculture worldwide. In this study, the effects of water supply on agronomic traits, ABA contents, drought response-associated physiological parameters, and expression patterns of the ABA receptor family genes during late stage were investigated. Under normal irrigation condition (NI, with irrigations performed prior to seed sowing, and at stages of jointing and flowering), the wheat cultivars, namely, the drought tolerant Cangmai 14 and the sensitive Jimai 325, displayed comparable agronomic traits (i.e. yields, yield components, and water use efficiencies), ABA contents, and the physiological traits associated with drought stress (i.e., proline and soluble sugar contents, and photosynthetic parameters). Under deficit irrigation (DI, without irrigation at flowering stage compared with NI), Cangmai 14 was much better on the agronomic traits, ABA contents, and the drought response-associated traits at late stage than Jimai 325. These results suggested that the improvement of drought response-associated traits contributed to the enhanced yield formation capacity of the drought-tolerant cultivars. Expression analysis on ABA receptor genes (i.e., PYL family ones) involving ABA signal perception indicated that TaPYL3, TaPYL5 and TaPYL8, three of the PYL family members, modified expression in the tested cultivars upon modified water supply copnditions, with more transcripts detected under DI than NI. Moreover, the expression levels of these genes were all shown to be higher in Cangmai 14 under DI than in Jimai 325. Transgene analysis on TaPYL3 validated that this gene exerted positive roles in modulating biomass production and photosynthetic function of plants under drought treatment. These results suggested the essential function of the ABA signaling genes in modulating plant drought response, whose enhanced transcription efficiencies positively impact on the drought response-associated physiological process, biomass production, and the yield formation capacity of wheat plants treated with DI through possibly an ABA-dependent pathway.

To assess and investigate the effects of application of superabsorbent polymer (SAP) and salicylic acid (SA) on performance of drought-affected sesame (Sesamum indicum L.), soil characteristics, and water productivity of irrigation (WPi). A randomized complete block design with split-strip plot arrangement and three replications in two successive cropping years was arranged. Two levels of irrigation consisting of supplying 50% and 100% of the sesame water requirement (deficit irrigation, DI and full irrigation, FI, respectively) were allocated to the main plots, and application of SAP (80 kg ha−1) was allocated to the subplots. Foliar application of SA (1 mM) and control was allocated to the strip plots. The results showed that the highest seed yield (SY) was obtained from DI, along with SAP and SA application. Under drought stress (DI), separate and simultaneous applications of SAP and SA increased WPi by 42% (SAP), 36% (SA), and 43% (SAP + SA), respectively, compared with control. The highest WPi was achieved through DI plus SAP application, which was 60% more than combination treatment of FI plus no-application of SAP. The results of principal component analysis (PCA) indicated that SY, seed weight per plant (SW), crop growth rate (CGR), and WPi were the effective variables of the first principal component (PC) and explained 67% of the total variance of the data. The nutritional management was effective in reducing drought stresses; moreover, the highest SY and biological yield (BY), CGR, the total amount of soil nitrogen (Soil N), and WPi were obtained in the simultaneous application of SAP and SA.

This study was carried out with the aim of determining the appropriate plant (Kc) and Pan (Kp) coefficients for Class A Pan by using the irrigation program that was monitored by soil moisture in th...

Plants are subjected to low use efficiency of water and nutrients in marginal lands such as calcareous soils. Moreover, plant wastes are not utilized optimally by the farmers. Hence, field trials w...

In this study, photosynthesis and assimilate translocation and their contribution to improving grain yield and harvest index (HI) of triticale under different N sources and irrigation regimes in an...

Salinity, water scarcity, and nitrogen (N) deficiency are the main limiting factors for plant production. However, over-irrigation and excessive N utilization can also limit the growth and biomass yield of leafy vegetables. The aim of this study is to investigate the growth regulation of spinach (Spinacia oleracea L.) under different levels of irrigation water salinity, water utilization, and nitrogen supply. Combinations of five salinity levels (1, 4, 7, 9, and 11 dS m−1) with three levels of water consumption including deficit irrigation (W–), full irrigation (W0) and over-irrigation (W+), and four levels of N supply (0, 50, 75, and 100% of N requirement) were examined under controlled greenhouse conditions. The least plant biomass, evapotranspiration (ET), and nitrogen use efficiency (NUE) were observed when high-saline water was applied in combination of water and N deficiency. However, the osmotic/drought effect is a short-term effect of salinity that can be further exacerbated by the condition W–. With increasing the fertilizer rate up to 150 mg N kg−1 soil, the plant growth traits increased significantly for all salinity levels; however, an excessive N utilization caused no significant increase. Water stress caused a morphological adaptation in the plant by reducing leaf area and ET, resulting in improved water use efficiency (WUE). With increasing salinity, WUE increased then decreased significantly. In other words, both the relative ET and relative yield were reduced with increasing salinity; however, at intermediate salinity levels (4 and 7 dS m–1), further decline in the former than in the latter resulted in higher WUE values. The stepwise regression analysis showed that the plant yield was affected mostly by WUE, ET, and leaves number (R2 = 0.983***). The findings of this study revealed that the reduced leaf area was the main growth regulation in the spinach plant under stress conditions, which ultimately could enhance WUE.

Drought tolerance of Brassica crops can be genetically improved by establishing plant ideotypes with improved yield responses associated with agronomic traits and biochemical markers. The objective of this study was to compare 20 Brassica oleracea L. accessions grown under two different water treatments (100% and 35% reintegration of evapotranspiration by irrigation) to select potential tolerant genotypes for organic cultivation based on several agronomic and biochemical parameters measured in response to drought stress. Significant differences were registered for the genotype and the irrigation regime and for their interaction (p < 0.0001 ***). A principal component analysis was performed to summarize the correlations among the analyzed phytochemicals and the stressed and not stressed genotypes and highlighted the importance of the antioxidant compounds as stress biomarkers. The present results showed that drought significantly reduces growth parameters and increases the amount of ascorbic acid and polyphenols compared to the irrigated control. Additionally, the results show that antioxidant metabolism increased by drought in some genotypes while others maintained a good biomass production by increasing the value of growth parameters considered. Based on the average sum of ranks (ASR) of morpho-physiological and biochemical parameters, the genotypes CR, CC, and BH were determined to be the most drought tolerant, whereas CI5, BU, and CV1 were determined to be the most susceptible. Due to the potential of these genotypes, further molecular and cellular research will be carried out to identify the genetic marker associated with the water stress response.

Among the solutions to climate change’s harmful effects, AS (Adaptation Strategies) are more feasible. In this study, four AS, Changing Cultivation Dates (CCD), Deficit Irrigation (DI), Improving Irrigation Performance (IIP), and Optimizing the Crop Pattern (OCP), were investigated. The results showed that the WUE (Water Use Efficiency) was declined when the cultivation date was changed for all crops in the baseline and increased after the cultivation date was brought forward to 7, 14, 14, 28, 28 days for tomato, wheat, corn, barley and cucumber, respectively, in the future period. Deficit irrigation of 30% increased the WUE in all crops. A 48% increase in irrigation performance reduced demand by 10%. Following the OCP and diminishing the cultivation area by 30% increased farmers’ total profit and reduced the water consumption volume by 9% and 11%, respectively, in the baseline and future periods. To study the effect of these AS on crop yield and allocated volume, a combination of crop model programming and the MOEPO (Multi-Objective Emperor Penguin Optimizer) was employed to minimize Vulnerability and maximize Reliability Indexes (Performance Indexes). In the supply section, three scenarios were examined. The results showed that DI, IIP, CCD and OCP were classified from the most to the least option based on improving the Performance Indexes.

Water is a key factor in global food security, which is critical to agriculture. The use of mathematical models is a strategy for managing water use in agriculture, and it is an effective way to predict the effect of irrigation management on crop yields if the accuracy of these models is demonstrated. The CROPWAT and SALTMED models were tested in this study, with water quantities applied to surface and drip irrigation (SI and DI) systems to estimate irrigation scheduling and wheat yield. For this purpose, field experiments were conducted for two consecutive years to study the effects of irrigation water levels of 80%, 100%, and 120% crop evapotranspiration (I80, I100, and I120) on the yield and water productivity (WP) of wheat in SI and DI systems. Irrigation treatments affected yield components such as plant height, number of spikes, spike length, and 1000-kernel weight, though they were not statistically different in some cases. In the I80 treatment, the biological yield was 12.8% and 8.5% lower than in the I100 and I120 treatments, respectively. I100 treatment under DI resulted in the highest grain yield of a wheat crop. When DI was applied, there was a maximum (22.78%) decrease in grain yield in the I80 treatment. The SI system was more water-consuming than the DI system was, which was reflected in the WP. When compared with the WP of the I80 and I100 treatments, the WP was significantly lower (p < 0.05) in the I120 treatment in the SI or DI system. To evaluate irrigation scheduling and estimate wheat yield response, the CROPWAT model was used. Since the CROPWAT model showed that increasing irrigation water levels under SI for water stress coefficient (Ks) values less than one increased deep percolation (DP), the I120 treatment had the highest DP value (556.15 mm on average), followed by the I100 and I80 treatments. In DI, I100 and I120 treatments had Ks values equal to one throughout the growing seasons, whereas the I80 treatment had Ks values less than one during wheat’s mid- and late-season stages. The I100 and I80 treatments with DI gave lower DP values of 93.4% and 74.3% compared with that of the I120 treatment (on average, 97.05 mm). The I120 treatment had the lowest irrigation schedule efficiency in both irrigation systems, followed by the I100 and I80 treatments. In both seasons, irrigation schedule deficiencies were highest in the I80 treatment with DI (on average, 12.35%). The I80 treatment with DI had a significant yield reduction (on average, 21.9%) in both seasons, while the irrigation level treatments with SI had nearly the same reductions. The SALTMED model is an integrated model that considers irrigation systems, soil types, crops, and water application strategies to simulate soil water content (SWC) and crop yield. The SALTMED model was calibrated and validated based on the experimental data under irrigation levels across irrigation systems. The accuracy of the model was assessed by the coefficients of correlation (R), root mean square errors (RMSE), mean absolute errors (MAE), and mean absolute relative error (MARE). When simulating SWC, the SALTMED models’ R values, on average, were 0.89 and 0.84, RMSE values were 0.018 and 0.019, MAE values were 0.015 and 0.016, and MARE values were 8.917 and 9.133%, respectively, during the calibration and validation periods. When simulating crop yield, relative errors (RE) for the SALTMED model varied between −0.11 and 24.37% for biological yield and 0.1 and 19.18% for grain yield during the calibration period, while in the validation period, RE was in the range of 3.8–29.81% and 2.02–25.41%, respectively. The SALTMED model performed well when simulating wheat yield with different water irrigation levels under SI or DI.

Lilium (lily) is known as an important cut flower whose quality and ornamental value may be negatively affected by deficit irrigation (DI); however, the adverse effects of DI could be alleviated by exogenous application of 24-epibrassinolide (EBR). Therefore, we conducted the present research to study the effects of different levels of soil water content (SWC) [100% (full irrigation), 75% (low DI), 50% (moderate DI), and 25% (severe DI)] and foliar spray of EBR (0.0, 0.75 and 1.5 μM) on certain morpho-physiological characteristics of Lilium “Fangio” (LA hybrid, Longiflorum x Asiatic). Different levels of DI were observed to alter lily’s morphological characteristics, affecting biochemical and physiological indices. Severe DI reduced plant height (11.11%), pedicel length (33.51%), and flower number (13.57%) while it increased the accumulation of proline (115.78%), electrolyte leakage (EL; 79.68%), and malondialdehyde (MDA; 40.35%) content. It also increased the water use efficiency (WUE; 135.59%) and saved water (66.7%). Foliar application of EBR significantly decreased the content of MDA (32.87%), on top of enhancing proline content (37.03%) and WUE (20.25%). The application of EBR (1.5 μM) on water stressed lily plants resulted in the improvement of chlorophyll content (41.46%) and activities of antioxidant enzymes (CAT and APX). Our results confirmed that applying irrigation at 75% SWC could reduce water inputs without affecting the ornamental value of lily. Overall, lily showed a moderate level of tolerance to water deficit by various mechanisms, such as a decrease of morphological parameters, maintenance of physiological function, an increase in WUE, and accumulation of osmolytes and enzymatic antioxidants. It could be concluded that severe water stress has to be avoided throughout the growing season of lilies, and if a foliar spray of EBR is used for the modulation and alleviation of the detrimental effects of drought stress, only moderate deficits are acceptable.

Yazd province is one of the most important centers for pistachio and seedling production in Iran due to its geographical location and climate. However, this province is also one of the arid and semi-arid regions, facing the serious problem of water shortage. The use of wastewater and deficit irrigation techniques is, therefore, very important for irrigating pistachio seedlings in this arid region. For this purpose, this study was conducted to investigate the effect of deficit irrigation with treated wastewater on water use efficiency, leaf nutrient uptake, and growth of 1-year-old pistachio seedlings. This study was performed as factorial experiment based on a completely randomized design with three repetitions; irrigation water quality was addressed in four levels of treated wastewater (W1), groundwater (W2), 50% treated wastewater and 50% groundwater (W3), and intermittent irrigation with treated wastewater and groundwater (W4). Also, four irrigation levels including deficit irrigation based on 100% (S1), 80% (S2), 60% (S3), and 40% (S4) field capacity were considered. At the end of the experiment, some morphological and physiological traits, such as SPAD in the leaves, relative water content (RWC), electrolyte leakage (EL), stem height and diameter, number of green leaves and leaf area, root fresh and dry weight, water use efficiency (WUE) and the leaf nutrient uptake, were evaluated. Statistical analyses showed that all morphological parameters were higher when irrigation was done with treated wastewater rather than groundwater. The results also suggested that water quality was more effective than deficit irrigation levels on the morphological traits. Also, while SPAD was affected by water quality, RWC and WUE were more under the influence of deficit irrigation levels. Further, physiological growth was higher in those seedlings irrigated on W1S1, whereas the highest WUE was obtained in W1S3. The analysis of variance also showed that the main effects of irrigation water quality and different levels of deficit irrigation, as well as the interaction of these treatments, were statistically significant at the level of 1% on all nutrients uptake in the investigated pistachio seedlings. According to the obtained results, wastewater could compensate for the negative effects of deficit irrigation in the moderate levels of deficit irrigation. The use of wastewater, along with the application of deficit irrigation techniques, can be, therefore, recommended as an important step to solve water shortage problems and increase water use efficiency in arid areas. The results of this study could provide information helpful for establishing orchards by using wastewater under water shortage conditions, especially in arid zones.

Current trends in the intensification of olive cultivation including irrigation have dictated a need to reconsider amendment management practices. The addition of organic wastes to agricultural soi...

Soil salinity and water scarcity adversely affect maize productivity. The use of biochar could enhance soil quality and increase the salt and/or drought threshold tolerance and yield of maize. Ther...

In this study, we investigated the effects of deficit drip irrigation practices on evapotranspiration, water-yield relations, and quality characteristics of two sesame varieties (Muganli-57 and Birkan) grown in the lysimeters under the Mediterranean climate conditions. Irrigation treatments were rainfed (non-irrigated) (I0), drip irrigation with 25% (DI25), 50% (DI50), 75% (DI75), and 100% (DI100) of cumulative evaporation (Epan) measured in Class A pan with three replications. The applied water was corrected by the percentage of vegetation cover until the full cover was attained. Evapotranspiration of Muganli-57 and Birkan ranged from 157.8 to 518.8 mm and 156.4 to 509.2 mm, on average, respectively. The yield values changed between 0.46 and 2.06 t ha−1 in Muganli-57 and between 0.35 and 1.95 t ha−1 in Birkan. Based on the 2-year results, water use efficiency (WUE) of Muganli-57 variety (3.5 kg ha−1 mm−1) was numerically higher than that of the Birkan variety (3.4 kg ha−1 mm−1). In both varieties, it was determined that deficit irrigation generally reduced the yield. However, WUE did not decrease monotonically with decreasing irrigation level. DI50 treatment maximized WUE for two varieties in both years while DI75 maximized WUE for Muganli-57 in 2014. Although irrigation-variety interaction affected relative water content, chlorophyll content index, and seed dry matter, their effect tended to be weak and inconsistent between the 2 years of the study. Deficit irrigation decreased the oil content of sesame and increased its protein content. Similarly, deficit irrigation treatments decreased the linoleic acid content and increased oleic acid content in 1 year but not the other. It was concluded that the Birkan variety is more suitable for irrigated conditions due to the growth characteristics and less saturated fatty acid content. On the contrary, Muganli-57 variety is suitable for non-irrigated conditions in terms of water economy and fatty acid composition.

This study aimed to estimate the morphological and physiological effects of chitosan foliar spray and/or three irrigation levels of 100%, 60%, and 40% of field capacity on grapevines grown in plastic containers to simulate water shortage conditions. The results showed that water irrigation deficit significantly reduced leaf area, trunk cross-sectional area, plant dry weight, root dry weight, relative chlorophyll content, leaf total carbohydrates, catalase activity, leaf midday water potential (ψ), relative water content (RWC), and crop evapotranspiration (ETc), but increased the proline content. Under well-watered condition, foliar-applied chitosan, in particular, 5 and 10 g·dm−3 increased plant growth and biomass production compared with untreated plants. Also, chitosan sprays during deficit irrigation conditions significantly improved plant tolerance to water deficit by enhancing the morphological and physiological parameters of grapevines. The results of this work suggest the opportunity to grow grapevines under deficit irrigation conditions using chitosan foliar spray. Increased plant biomass and root weight, and the positive impacts of chitosan as antitranspirant on increased ψ, RWC, and decreased ETc play the main role in drought stress avoidance mechanisms in grapevines raised under moderate deficit irrigation conditions.

Background Drought is one of the most important environmental stresses that can adversely influence soil properties, plant growth, and productivity of agricultural crops including eggplant as an important vegetable crop. In recent years, the use of agricultural wastes has been reported as a beneficial and sustainable measure in soil water retention and fertility enhancement. In this study, the effect of date palm and pistachio biochar, vermicompost and a combination of biochar and vermicompost was evaluated on eggplant growth, yield and water use efficiency under deficit irrigation. Materials and methods The experiment was done in a split-split plot based on randomized complete block design with three replications and under open field conditions. The main plot was deficit irrigation in three levels of 100, 75 and 50% of plant water requirement (PWR), and the sub-plots were vermicompost in two levels of 0, 1500 g m−2, and biochar in three levels of 0, 500 g m−2 of the pistachio biochar and 500 g m−2 of the date palm biochar. Results The results showed that soil amendment with vermicompost and pistachio biochar and 100% PWR showed the best plant growth and performance. The early crop yield was highest under pistachio biochar and 50% PWR, while the total plant yield was highest under combined application of vermicompost and pistachio biochar at 100% PWR. The plant water use efficiency was maximum under mixed application of vermicompost and pistachio biochar at 50% PWR. Application of both pistachio biochar and vermicompost at 100% PWR resulted in the highest leaf concentrations of nitrogen, phosphorus, potassium, iron and manganese. The highest levels of physiologically important stress metabolites, including malondialdehyde, guaiacol peroxidase, superoxide dismutase and catalase enzymes were found in treatments without amendments or only with vermicompost and 50% PWR. Conclusion The results indicate that under normal and particularly water deficit conditions, vermicompost and biochar increased eggplant vegetative growth, yield and water use efficiency.

Water scarcity negatively affects maize yield, whereas biochar could enhance soil physical properties and improve the growth and water productivity (WP) of maize. Thus, field experiments were condu...

Water shortage is the main limitation for agricultural production in many parts of the world. Drought or unavailability of water may seriously limit plant growth as well as yield. A pot experiment ...

Due to congenital features, avocado (Persea americana Mill.) trees are substantial water users relative to other fruit trees. The current growing deficiency of water resources, especially in arid and semi-arid avocado-producing areas, has led to the demand for more sustainable water-saving measures. The objective of this review was to analyze the role of deficit irrigation as a strategy to face climate change and water scarcity through achieving efficiency, saving water, and maximizing the benefits that could be achieved at the level of the irrigated agricultural system. Particular attention is devoted to studies performed in the subtropical Mediterranean climate, in which irrigated avocado orchards are common. These studies analyzed irrigation demand, deficit irrigation, and determination of water status through physiological parameters, leading to possible sustainable irrigation programs for avocado in the context of water shortage scenarios. Through these insights, we conclude that under the current climatic circumstances with respect to available water resources, avocado farming requires sustainable resilience strategies to reduce irrigation water consumption without affecting the yield and quality of the fruits. Water stress inevitably affects the physiological processes that determine yield. Therefore, an admissible yield loss is required with smaller fruits and water savings made through deficit irrigation strategies. In addition, modern consumers tend to prefer foods based on sustainability, i.e., there is a high demand for socially responsible and environmentally friendly products.

A 2-years field experiment in a split-split plot arrangement was considered to investigate the effects of different irrigation water salinity [0.45 (well water, S1), 1.0 (S2), 2.0 (S3), 3.0 (S4) dS m−1], irrigation water levels [100% (I1), 75% (I2) and 50% (I3) of saffron water requirement (WR)] and planting methods [basin (P1) and in-furrow (P2)] on the dynamics of salt ions and their uptake by saffron plant (Crocus sativus L.). The electrical conductivity of soil saturation extract (ECe) was increased by 104% in S4 compared to control (S1), on average, in two growing seasons. S4 treatment increased concentration of sodium (Na+), calcium (Ca2+), potassium (K+) and chloride (Cl−) in soil by 102%, 92%, 124% and 128% in comparison with S1, on average, in two growing seasons. The concentration of Na+, Ca2+, K+ and Cl− in soil in S4 were 30%, 15%, 28% and 29% higher and NO3 was 30.3% lower in I1 in comparison with I3, respectively. The ions concentration in soil were 3.5–14.7% higher in P1 in comparison with those in P2. Leaf Na+, Ca2+ and Cl− concentration was increased by increase in irrigation water salinity while K+, nitrogen (N) and phosphorus (P) concentrations were decreased by 28.4%, 25.7% and 29.8% in S4 in comparison with that obtained in S1, on average, which is presumably due to reduced NO3 and P concentrations in soil and increased Na+ uptake by saffron. Also, deficit irrigation reduced soil and leaf ions (Na+ and Cl−) threshold and increased the slope of relative yield-ions concentration reduction function, which indicated that water stress aggravates saffron sensitivity to salinity and ions concentration in soil and leaf. Results indicated that saffron was more sensitive to Na+ concentration in soil extract compared with Cl−. Na+ and Cl− threshold was 19.3% and 27.1% higher in P2, on average, in different irrigation levels, respectively. Therefore, the in-furrow planting method is suggested to cope with unfavorable saffron field conditions.

Increased water demands and climate change have reduced agricultural water resources in areas that experience water shortages. Therefore, a field experiment was conducted in an arid region of Saudi Arabia to evaluate the effects of two drip irrigation systems [surface (DI) and subsurface (SDI)] and three irrigation levels [100%, 70%, and 50% of crop evapotranspiration (I100, I70, and I50, respectively)] on the growth traits, tuber yield, and irrigation water use efficiency (IWUE) of potato (Solanum tuberosum L.) during the 2017 and 2018 growing seasons. θv was 13.74 and 23.85% lower under the DI system and 11.90 and 24.14% lower under the SDI system with the I70 and I50 treatments, respectively, than with the I100 treatment, and was also lower under the DI system than under the SDI system. The fresh and dry vegetative parts of the plants were heavier with the I100 treatment under the SDI system than with the I70 and I50 treatments under the DI system, and the leaf area indexes were also significantly lower with I70 and I50 than with I100 but were not affected by the irrigation system. The fresh and dry tuber yields were lowest with the I50 treatment (23.97 and 3.93 Mg ha−1, respectively), followed by I70 (28.61 and 4.98 Mg ha−1, respectively), and I100 (34.43 and 6.67 Mg ha−1, respectively) and were higher under the SDI system than under the DI system. By contrast, IWUE was highest with the I50 treatment (6.49 and 7.02 kg m−3) and lowest with the I100 treatment (5.62 and 5.85 kg m−3) under the DI and SDI systems, respectively. These findings indicate that full irrigation (I100) with the SDI system maximizes potato yield but decreases IWUE, whereas integration of the SDI system with deficit irrigation is effective in improving water productivity due to less water being consumed, allowing these practices to be used under scarce water conditions.

HighlightsLater planting and greater site elevation or latitude decreased seasonal growing degree days and cotton yield in Kansas.Higher irrigation capacity (rate) usually increased lint yield, which was probably due to increased early boll load.Strategies for splitting land allocations between high irrigation rates and dryland did not increase production.Cotton may reduce irrigation withdrawals from the Ogallala aquifer, but the Kansas growing season limits production.Abstract. Precipitation in the western Great Plains averages about 450 mm, varying little with latitude and providing 40% to 80% of potential crop evapotranspiration (ETc). Supplemental irrigation is required to fully meet crop water demand, but the Ogallala or High Plains aquifer is essentially non-recharging south of Nebraska. Pumping water from this aquifer draws down water tables, leading to reduced water availability and deficit irrigation to produce an alternate crop such as cotton (Gossypium hirsutum L.) with a lower peak water demand than corn (Zea mays L.). Our objective was to compare simulated cotton yield response to emergence date, irrigation capacity, and application period at three western Kansas locations (Colby, Tribune, and Garden City) with varying seasonal energy or cumulative growing degree days (CGDD) and compare split center pivot deficit irrigation strategies with a fixed water supply (i.e., where portions of the center pivot land area are managed with different irrigation strategies). We used actual 1961-2000 location weather records with the GOSSYM simulation model to estimate yields of cotton planted into soil at 50% plant-available water for three emergence dates (DOY 145, 152, and 159) and all combinations of irrigation period (0, 4, 6, 8, and 10 weeks beginning at first square) and capacity (2.5, 3.75, and 5.0 mm d-1). Simulated lint yield and its ratio to ETc, or water use efficiency (WUE), consistently decreased with delayed planting (emergence) as location elevation or latitude increased due to effects on growing season CGDD. Depending on location, simulated cotton lint consistently increased (p = 0.05) for scenarios with increasing irrigation capacity, which promoted greater early season boll load, but not for durations exceeding 4 to 6 weeks, probably because later irrigation and fruiting did not complete maturation during the short growing season. Cotton WUE generally increased, with greater yields resulting from earlier emergence and early high-capacity irrigation. We calculated lower WUE where irrigation promoted vigorous growth with added fruiting forms that delayed maturation and reduced the fraction of open bolls. The irrigation strategy of focusing water at higher capacities on a portion of the center pivot in combination with the dryland balance did not increase net yields significantly at any location because the available seasonal energy limited potential crop growth and yield response to irrigation. However, the overall net lint yield was numerically larger for focused irrigation strategies at the southwest Kansas location (Garden City). Based on lint yields simulated under uniform or split center pivot deficit irrigation, we conclude that cotton is poorly suited as an alternative crop for central western and northwestern Kansas because of limited growing season CGDD. Keywords: Cotton, Crop simulation, Deficit irrigation, Evapotranspiration, Irrigation capacity, Split center pivot irrigation, Water use efficiency, Yield limiting factors.

This study evaluated the yield and water productiivty response of quinoa to regulated deficit irrigation (RDI), partial root-zone drying (PRD) and conventional deficit irrigation (DI) and full irrigation (FI) using surface (SD) and subsurface drip (SSD) systems in 2016 and 2017 in the eastern Mediterranean region of Turkey. The treatments consisted of RDI, PRD50, DI50, DI75 and FI. A rainfed treatment (RF) was also included in the study. The experimental design was split plots with four replications. DI75 and DI50 received 75 and 50% of FI, respectively. PRD50 received 50% of FI, but from alternative laterals. RDI received 50% of FI during vegetative stage until flowering, and then received 100% of water requirement. The results showed that quinoa under SD used slightly more water than SSD due to reduced surface evaporation. RDI resulted in water saving of 23 and 21% for SD and SSD, respectively, compared to FI; and RDI produced statistically similar grain yields to FI. DI75 treatment resulted in water savings of 16% for both drip methods in the first year and 10 and 25% for SD and SSD systems, respectively, in the second year. PRD50 produced greater yield than DI50 eventhough they received the same amount of irrigation water. RF and PRD50 treatments resulted in significantly greater water productivity (WP) values than other treatments. There was no significant difference between SD and SSD regarding the grain and dry matter yields and WP values. Thus, RDI and DI75 appear to be good alternatives to FI for sustainable quinoa production in the Mediterranean region.

Developing improved water management strategies and on-farm cultural practices are important in reducing pomegranate (Punica granatum L. cv Wonderful) production costs. A pomegranate orchard establ...

As an important medicinal plant used in traditional and modern medicine, chili peppers are sensitive or moderately sensitive to drought or salt stress, respectively. Therefore, potential changes due to foliar-applied glutathione (GSH; 0, 0.4 and 0.8 mM) response on growth, yield, and physio-biochemical attributes, as well as water use efficiency (WUE) and fruit alkaloid capsaicin of chili pepper plants were investigated when grown under deficit irrigation in salt-affected soil (EC = 6.74 dS m–1). Two deficit irrigation water (DiW) regimes (80% and 60% of soil field capacity; FC) were used versus 100% of FC as a control. Both DiW treatments negatively affected growth and yield parameters, SPAD chlorophyll index, nutrient status, K+/Na+ ratio, and plant anatomical features. In contrast, osmoprotectants, ascorbate, glutathione, capsaicin, and phenolic contents, as well as WUE were increased in association with higher Na+ and Cl– contents. However, exogenously-applied GSH caused significant increases in the above-mentioned parameters along with an additional increase in osmoprotectants, antioxidants, and capsaicin contents, and a decrease in Na+ and Cl– levels compared to corresponding controls. The highest WUE, growth, and fruit yield responses were recorded at 0.8 mM GSH applied to plants under DiW at 80% FC + salinity (6.74 dS m–1). Therefore, this study suggested the use of leafy-applied GSH at 0.8 mM for satisfactory growth and yield with the highest WUE of chili pepper plants grown under salt-affected conditions with deficit irrigation.

The present study was carried out at Water Management Research Centre, University of Agriculture, Faisalabad, Pakistan, to investigate the effect of row spacing, deficit irrigation and dual plantation on tomato yield grown in high tunnel under polyethylene black mulch and drip irrigation system. The field experiment layout comprised of three rows spacing (S1, S2 and S3) as (0.45, 0.60, and 0.75 m respectively) and two irrigation levels (I1 and I2) as (100% and 75% of required irrigation respectively). In addition, a dual plantation treatment spaced at 0.45 m was also investigated under both irrigation levels. Results showed that the total fruit yield was significantly influenced by row spacing and irrigation level, however, their interaction was non-significant. The 100% irrigation gave 6.53, 4.49, and 5.94% more yield than 75% irrigation treatment under 0.45, 0.60, and 0.75 m row spacing, respectively. However, the irrigation water use efficiency was found to be higher in deficit treatment (75% irrigation) by 25.16, 27.60, and 25.86% than full irrigation treatments under 0.45, 0.60, and 0.75 m row spacing, respectively. The results of single and dual plantation showed that dual plantation increased the fruit yield by 7.62 and 11.28% than the single plantation under full and deficit irrigation respectively and covering approximately the same area.

This study presents an evaluation of soil organic carbon (SOC) and stock (SOCstock) for the whole rooting depth (60 cm), spaced 55 months in two adjacent olive orchards with similar conditions but different tree densities: (i) intensive, planted in 1996 at 310 tree ha−1; (ii) superintensive, planted in 2000 at 1850 tree ha−1. This was carried out to test the hypothesis that olive orchards at different plant densities will have different rates of accumulation of SOC in the whole soil rooting depth. SOC increased significantly in the superintensive orchard during the 55-month period, from 1.1 to 1.6% in the lane area, and from 1.2 to 1.7% in the tree area (average 0–60 cm), with a significant increase in SOCstock from 4.7 to 6.1 kg m−2. In the intensive orchard, there was not a significant increase in SOCstock in 0–60 cm, average of 4.06 and 4.16 kg m−2 in 2013 and 2018, respectively. Results indicate a potential for a significant increase in SOC and SOCstock in olive orchards at higher tree densities when combined with temporary cover crops and mulch of chopped pruning residues. The increase is associated with an increase in SOC, mainly at a 0–15 cm depth. Results also point to the need for improve our monitoring capabilities to detect moderate increases in SOC., This received funding by projects PID2019-105793RB-I00 and Severo Ochoa and María de Maeztu Program for Centers and Units of Excellence in R&D (Ref. CEX2019-000968-M) both Spanish Government, SHui (European Commission Grant Agreement number: 773903), TUdi (European Commission Grant Agreement number 101000224) and EU-FEDER funds., With funding from the Spanish government through the "Severo Ochoa Centre of Excellence" accreditation (CEX2019-000968-M).

The benefits of water-saving techniques such as alternate furrow and deficit irrigations need to be explored to ensure food security for the ever-increasing population within the context of declining availability of irrigation water. In this regard, field experiments were conducted for 2 consecutive dry seasons in the semiarid region of southwestern Ethiopia and investigated the influence of alternate furrow irrigation method with different irrigation levels on the yield, yield components, water use efficiency, and profitability of potato production. The experiment comprised of 3 irrigation methods: (i) conventional furrow irrigation (CFI), (ii) alternate furrow irrigation (AFI), and (iii) fixed furrow irrigation (FFI) combined factorially with 3 irrigation regimes: (i) 100%, (ii) 75%, and (iii) 50% of the potato water requirement (ETC). The experiment was laid out in randomized complete block design replicated thrice. Results revealed that seasonal irrigation water applied in alternate furrows was nearly half (170 mm) of the amount supplied in every furrow (331 mm). Despite the half reduction in the total amount of water, tuber (35.68 t ha−1) and total biomass (44.37 t ha−1) yields of potato in AFI did not significantly differ from CFI (34.84 and 45.35 t ha−1, respectively). Thus, AFI improved WUE by 49% compared to CFI. Irrigating potato using 75% of ETC produced tuber yield of 35.01 t ha−1, which was equivalent with 100% of ETC (35.18 t ha−1). Irrigating alternate furrows using 25% less ETC provided the highest net return of US$74.72 for every unit investment on labor for irrigating potato. In conclusion, irrigating alternate furrows using up to 25% less ETC saved water, provided comparable yield, and enhanced WUE and economic benefit. Therefore, farmers and experts are recommended to make change to AFI with 25% deficit irrigation in the study area and other regions with limited water for potato production to improve economic, environmental, and social performance of their irrigated systems.

6 páginas.- 3 figuras.- 1 tablas.- 28 referencias, BACKGROUND Water scarcity is currently affecting many areas of the world, reaching worrying levels in drought areas such as southern Spain. To cope with this issue, researchers in the agricultural sector have implemented deficit irrigation strategies intended to reduce water consumption by increasing fruit quality. Almond is among the most popular tree nuts worldwide and also the most nut cultivated in Spain. Almond consumption, together with other nuts, has been widely associated with improvements in cardiovascular health, metabolic syndrome and diabetes owing to their bioactive compounds such as polyphenols. Water deficit strategies generate hydroSOStainable almonds, raised under water stress conditions, with high content of bioactive compounds. The aim of this work was to study the relationship between water stress, color and polyphenols in hydroSOStainable almonds. For this, instrumental color, total phenolic content and phenolic compounds were measured and correlated using Pearson's correlation. RESULTS The results showed a strong relationship between water stress, color and polyphenols of almonds, showing that increasing water stress in plants up to ~100 MPa × day values of stress integral increase the polyphenols in almonds, leading to a reddish color. CONCLUSION Finally, this research demonstrated that implementing water‐saving strategies help to improve the phenolic content and color of hydroSOStainable almonds and also that isorhamnetin‐3‐O‐rutinoside, isorhamnetin‐3‐O‐glucoside and kaempferol‐3‐O‐glucoside could be important markers of hydroSOStainable almonds (cv. Vairo). Besides, hydroSOStainable almonds could be an important source of phenols, providing 25% of the estimated total polyphenolic daily intake. © 2020 Society of Chemical Industry, The study has been funded by the Spanish Government (Ministerio de Ciencia e Innovación (MCI), Agencia Estatal de Investigación (AEI), through a coordinated research project (hydroSOS) including the Universidad Miguel Hernández de Elche (AGL2016-75794-C4-1-R, Productos hidroSOStenibles: identificación de debilidades y fortalezas, optimización del procesado, creación de marca propia, y estudio de su aceptación en el mercado europeo, hydroSOS foods) and the Universidad de Sevilla (AGL2016-75794-C4-4-R); these projects have been also funded by Fondo Europeo de Desarrollo Regional (FEDER) ‘Una manera de hacer Europa’, (MCI/AEI/FEDER, UE). The author M. Cano-Lamadrid was funded by a Formación de Profesorado Universitario (FPU) grant from the Spanish Ministry of Education (FPU15/02158).