Foliar Application of Proline and Valine Enhances Drought Tolerance in Lentil Varieties

به‌منظور بررسی اثر کودهای آلی و شیمیایی بر عملکرد و اجزای عملکرد کلزا، آزمایشی در مزرعه‌ی دانشکده کشاورزی مشهد در سال 1391 اجرا شد. تیمارهای این آزمایش شامل کود‌های آلی و آبیاری بود. تیمارهای کودی شامل، کمپوست زباله شهری، ورمی‌کمپوست، کود دامی کاملاً پوسیده و کود شیمیایی نیتروژنه بود. آزمایش به‌صورت اسپلیت‌پلات و در قالب طرح بلوک‌های کامل تصادفی و در سه تکرار اجرا شد. تیمارهای آبیاری در کرت اصلی و تیمارهای کودی در کرت‌های فرعی قرار گرفتند. در طول فصل زراعی از صفات مورد‌نظر یادداشت‌برداری به‌عمل آمد. نتایج آزمایش نشان داد که عملکرد دانه، تعداد غلاف در بوته و وزن هزار‌دانه در تیمار آبیاری در مقایسه با کم‌آبیاریبه‌ترتیب 21 ، 5/9و 17درصدبیشتر بود. تیمار استفاده از 50‌تن در هکتار کود دامی در مقایسه با بقیه تیمارها در شرایط کم‌آبیاری بیشرین عملکرد دانه را تولید نمود (875‌کیلوگرم در هکتار).بعد از تیمار 50‌تن در هکتار کود دامی، تیمار کود شیمیایی و تیمار 11‌تن در هکتار ورمی‌کمپوست با عملکردی معادل، 820 و 814‌کیلو‌گرم در هکتار در مرحله بعدی قرار داشتند. در شرایط آبیاری کامل اختلاف تیمارهای کودهای آلی با کود شیمیایی بیش‌تر شد و تیمار کود شیمیایی با عملکرد دانه‌ای معادل 1284‌کیلو‌گرم در هکتار تفاوت زیادی با بقیه تیمارها نشان داد. بنا‌براین به‌نظر می‌رسد که گیاه کلزا در شرایط کمبود رطوبت عکس‌العمل بهتری به کودهای دامی و ورمی‌کمپوست نشان می‌دهد و در صورتی‌که از نظر اقتصادی مقرون به‌صرفه باشد، امکان جاگزینی آن‌ها در این‌گونه شرایط با کودهای شیمیایی میسر می‌باشد.

The combined effect of deficit irrigation by treated wastewater and organic amendment on quinoa (Chenopodium quinoa Willd.) productivity

Lentils are a significant source of plant protein and are cultivated across Asia, Europe, and North Africa. Plants are subjected to various environmental stresses, which can hinder growth, yield, and productivity. 5-aminolevulinic acid (ALA) is a compound that acts as a precursor in the biosynthesis of tetrapyrroles and can increase plant tolerance to different abiotic stressors. However, the effects of exogenously applied ALA on lentil growth, yield, and physiological parameters under rain-fed and supplemental irrigation conditions are not well-known. In this study, a split plot experiment was conducted to investigate the impact of ALA foliar application and supplemental irrigation on lentil (Lens culinaris Medik.). The experiment was designed based on a randomized complete block with three replications. The main plot included four levels of supplemental irrigation [(supplementary irrigation in the flowering and early seed-filling stages, supplementary irrigation in the flowering stage, supplementary irrigation in the early seed-filling along with rain-fed conditions (no irrigation)]. The subplot considered foliar application of ALA at varying levels [(0 (control), 50 and 100 ppm)]. The results showed that water regimes and foliar spray with ALA significantly (P ˂ 0.01) affected plant height, number of pods per plant, pod weight, number of seeds per pod and weight of 1000 seeds, biological yield, seed yield, and harvest index. The highest total chlorophyll content was observed in plants that were subjected to supplementary irrigation in flowering and early seed filling stages and foliar sprayed with 100 ppm ALA. The study also found that exogenous ALA improved drought tolerance in lentil plants under rain-fed conditions mainly by regulating antioxidant enzymes, which ultimately protected the cellular membranes against overproduction of H2O2. Furthermore, ALA application increased total carbohydrate contents at all supplemental irrigation levels, but the rate was higher in complementary irrigation conditions during flowering and early seed-filling stages. Malondialdehyde (MDA), H2O2, and proline contents were increased in field-grown plants under rain-fed conditions without exogenous ALA application. In conclusion, this study sheds light on the effects of ALA foliar spray and supplemental irrigation on lentil growth, yield, and physiological parameters. The findings suggest that exogenous ALA can improve plant tolerance to various abiotic stressors and enhance plant growth, yield, and physiological parameters.

Introduction Chickpea (Cicer arietinum L.), an annual with indeterminate growth, is one of the most important food legumes. Loss of seeds due to pod borer (Heliothis armigera) attack is prevalent. Such loss of pods may affect the yield and yield components. The source-sink relationship changes during growth stages. Some factors influence this relationship including nitrogen fertilizer and water. This experiment was conducted in order to study the effects of nitrogen fertilizer, supplementary irrigation and depodding on yield and yield components of chickpea (var. ILC482). Materials & Methods The experiment was conducted as split-split plot based on a randomized complete block design with three replications at Agricultural Research Station of Ferdowsi University of Mashhad, during growing season of 2012. Main plot was nitrogen fertilizer including 30, 75 and 150 kg N/ha and sup plot was irrigation regimes including full irrigation, supplementary irrigation at flowering and supplementary irrigation at flowering, seed podding and depodding including 0, 25%, 50% and 75% as sub subplot. Leaf and stem dry weight, seed weight per plant, shoot weight, pod number per plant, grain number per plant, 100-seed weight and harvest index of chickpea were all recorded. Results & Discussion The results indicated that all traits excluded of harvest index were higher in 150 kg N/ha treatment than other treatments. Nitrogen rate of 150 kg/ha produced the highest seed weight (3.8 g/plant). The highest harvest index (36%) was obtained from 30 kg/ha N treatment. Supplementary irrigation at flowering and podding stages with grain yield 4.4 g/plant was higher than full and supplementary irrigation at flowering. Supplementary irrigation at flowering and podding stages produced the highest harvest index (39%). In irrigation regimes including full irrigation and supplementary irrigation at flowering stage, 75% depodding decreased seed weight to 60%, but this was 45% in Supplementary irrigation at flowering and podding stages. In this interaction, full irrigation and 0% depodding (control), produced the highest seed weight (195 g/m2). The lowest seed weight (40 g/m2) was obtained from supplementary irrigation at flowering stage and 75% depodding. Supplementary irrigation at flowering and podding stages with 25% depodding produced the highest harvest index (45%) too. Increase of harvest index mostly was related to improve photosynthesis and remobilization in mid drought stress and also low depodding (by devotion photosynthetic assimilates to un-removed pods). The highest shoot weight was obtained from 150 kg N/ha (12.8 g/plant) and full irrigation (14.3 g/plant). Depodding decreased the most of mentioned traits significantly. 75% depodding decreased seed weight and shoot dry weight to 56% and 30% respectively compared to control. The lowest harvest index (23%) was obtained from 75% depodding. In nitrogen rate of 75 kg/ha, the highest (177 g/m2) and lowest (46 g/m2) seed weight was obtained from 0% and 75% depodding, respectively. This result also was observed in traits of seed number and pod number in this interaction. High N application improved the ability of plant to compensate the pods that removed. All of traits including pod number, seed number, harvest index and shoot dry weight had positive and significantly correlation with seed weight. Pod number (75%) had highest correlation with yield. Conclusion Generally, increasing depodding intensity decreased grain yield. But nitrogen fertilizer application decreased the negative effects of depodding in low levels. Among irrigation regimes, supplementary irrigation at flowering and depodding stages was best treatment, therefore under water deficit condition, supplementary irrigation at flowering and podding stages recommend. Under severe stress condition (supplementary irrigation at flowering stage), high nitrogen application did not effect on seed weight. In this condition, favorite yield will obtain by 30 kg nitrogen fertilizer application as starter.

Introduction Lack of water resources and drought stress is one of the most important characteristics of arid areas. Therefore, selecting the resistant plant and appropriate irrigation method is the best approach to manage water resources in these areas. Furthermore, lentil (Lens culinaris Med) as a cold spring legume is one of the most suitable plant under these conditions. The deficit irrigation method is one of the most important options for decreasing water losses and maximize water use efficiency in arid areas. However, the purpose of this study was evaluation of managing drought stress using deficit irrigation and its effect on lentil production and water use efficiency in climatic condition of Saravan. Materials and methodsFor evaluation of deficit irrigation on lentil production a split plot experiment based on a randomized complete block design with four replications was conducted in the Agricultural Research Station, Higher Educational Complex of Saravan during the growing season of 2018-2019. Main plots were including four levels of irrigation (60, 80, 100 and 120%). Sub plots were two lentil landraces (Baluchestan and Kurdestan). Planting was done on November 30. Moreover, irrigation was carried out in control (full irrigation) whenever 35% of allowed water depletion was extracted at soil depth of 20 cm. At each irrigation interval, the soil moisture was returned to the field capacity point at depth of 60 cm. The amount of deficit moisture content of different layers of soil was calculated from the following equation:MDControl= (Ɵ‌FC‌- Ɵ10cm) + (Ɵ‌FC‌- Ɵ20cm) +…..+ (Ɵ‌FC‌- Ɵ60cm) (1) In this equation, MD was the amount of moisture deficiency based on mm, ƟFC was the volumetric moisture content of the soil in the field capacity of the field and Ɵ 10cm, 20cm, 30cm, 40cm, 50cm and 60cm were the volume of soil moisture at a depth of 10, 20, 30, 40, 50 and 60 cm, respectively.The amount of irrigation water for each plot in the control treatment was calculated based on the following equation:IControl= MDControl × A (2) In the equation of 2, I was the amount of irrigation water based on liter, MD was the amount of moisture deficiency (mm) calculated in equation 1 and A plot area (m2). Deficit irrigation was done at the same time as the control treatment, but irrigation was carried out at each irrigation interval according to different levels of deficit irrigation (60, 80).The amount of water at different levels of deficit irrigation was calculated as follows:I Deficit irrigation at 80 percentage= IControl ×0.80I Deficit irrigation at 60 percentage= IControl ×0.60Results and discussionsOverall, the results showed that the effect of deficit irrigation on grain yield, biological yield, harvest index, number of pods and seed per plant and water use efficiency was significant. The highest grain yield was obtained for Baluchestan cultivar in 120 and 100% water requirement with 680 and 643 kg ha-1, respectively. Furthermore, the highest harvest index was obtained in Baluchestan cultivar and 80% water treatment (0.24) treatments. Although, Baluchestan cultivar and 80% water requirement treatments encountered with 10% reduction in grain yield compared to 100% water requirement, its biological yield decreased 27% compared to 100% water requirement, which eventually led to an increase in harvest index. On the other hand, the greatest water use efficiency was observed in Balochistan cultivar and 80% water requirement treatment with 2.9 kg ha-1 mm-1. Although the yield of 80% water requirement was 58 kg ha-1 less than 100% water requirement, but its water use efficiency was 0.3 kg ha-1 mm-1 more than 100% water requirement. Conclusions Therefore, given that the area is considered as arid area, it is possible by reducing irrigation water and allocating it to critical stages especially flowering and pod filling stages and also other crops improve grain yield and the water use efficiency.

In northern Togo where rainfed maize is one of the major crops grown, agriculture is subject to frequent yield losses due to erratic rainfall. To ensure food availability and improve agricultural productivity, it is necessary to produce maize during the dry season under irrigation. A sound application of full and deficit irrigation requires a thorough understanding of the crop parameters and yield response to water. Thus, this study investigated the effect of full and deficit irrigation on maize plant above-ground biomass, leaf area index, canopy cover, plant height, and grain yield. A field experiment was carried out from December 2017 to April 2018 in northern Togo at the agronomic research institute. Full irrigation (FI), 80% FI, and 60% FI treatments were applied. The results showed that in the late-season stage, the differences in biomass between FI and 60% FI were significant (p < 0.05). On average, FI had the greatest grain yield (2 200.4 kg/ha), while the lowest grain yield was recorded under 60% FI (1,068.3 kg/ha). The grain yield differences between FI and 60% FI were significant. Nevertheless, the grain yield differences between FI and 80% FI were not significant (p > 0.05). 80% FI had water use efficiency (WUE) (0.22 kg/m3) similar to that of FI (0.21 kg/m3), on average. The results of this study illustrate that deficit irrigation must be carefully managed since slight differences in the application volumes affect the biomass and yield of maize significantly. Under a moderate level of deficit irrigation (vegetative and reproductive growth stages) the biomass and the grain yield of maize are reduced. However, a moderate level of deficit irrigation during the vegetative growth stage could result in similar values of WUE to that of FI.

Effects of deficit irrigation during flower initiation of two blackcurrant (Ribes nigrum L.) cultivars

Meta-analysis of crop yields of full, deficit, and partial root-zone drying irrigation

Drought and mandatory water restrictions are limiting the availability of irrigation water in many important blueberry growing regions, such as Oregon, Washington, and California. New strategies are needed to maintain yield and fruit quality with less water. To address the issue, three potential options for reducing water use, including deficit irrigation, irrigation cutoffs, and crop thinning, were evaluated for 2 years in a mature planting of northern highbush blueberry ( Vaccinium corymbosum L. ‘Elliott’). Treatments consisted of no thinning and 50% crop removal in combination with either full irrigation at 100% of estimated crop evapotranspiration (ET c ), deficit irrigation at 50% ET c (applied for the entire growing season), or full irrigation with irrigation cutoff for 4–6 weeks during early (early- to late-green fruit) or late (fruit coloring to harvest) stages of fruit development. Stem water potential was similar with full and deficit irrigation but, regardless of crop thinning, declined by 0.5–0.6 MPa when irrigation was cutoff early and by >2.0 MPa when irrigation was cutoff late. In one or both years, the fruiting season was advanced with either deficit irrigation or late cutoff, whereas cutting off irrigation early delayed the season. Yield was unaffected by deficit irrigation in plants with a full crop load but was reduced by an average of 35% when irrigation was cutoff late each year. Cutting off irrigation early likewise reduced yield, but only in the 2nd year when the plants were not thinned; however, early cutoff also reduced fruit soluble solids and berry weight by 7% to 24% compared with full irrigation. Cutting off irrigation late produced the smallest and firmest fruit with the highest soluble solids and total acidity among the treatments, as well as the slowest rate of fruit loss in cold storage. Deficit irrigation had the least effect on fruit quality and, based on these results, appears to be the most viable option for maintaining yield with less water in northern highbush blueberry. Relative to full irrigation, the practice reduced water use by 2.5 ML·ha −1 per season.

Deficit irrigation differentially modulates rhizosphere microbial community and metabolites of two potato genotypes differing in drought tolerance.

A field study was established at the University of Wyoming James C. Hageman Sustainable Agriculture Research and Extension Center in 2020 with the following objectives: (1) Assess the performance of alfalfa–grass mixtures under reduced irrigation. (2) Identify the best grass species and optimum seeding ratio of alfalfa–grass mixtures for improved productivity and nutritive value under full and deficit irrigations; (3) Compare the net economic return from different seeding ratios of alfalfa–grass mixtures under full and deficit irrigations. Treatments included monocrop alfalfa, 75–25 ratio, 50–50 mixed row planting, and 50–50 alternate row planting of alfalfa with each of three perennial cool‐season grasses (orchardgrass, tall fescue, and meadow bromegrass) under full and deficit irrigation. Under full irrigation, 75–25 mixture with tall fescue produced the highest 2‐year total forage dry matter, while alternate row planting of alfalfa and orchardgrass produced the highest under deficit irrigation. Deficit irrigation affected forage dry matter yield negatively. Economic analysis revealed that a 75–25 mixture of alfalfa and tall fescue under full irrigation produced the highest net present value (NPV). Although deficit irrigation reduced costs, that did not result in higher NPV than full irrigation. However, alternate row planting with orchardgrass under deficit irrigation produced an NPVsimilar to the treatments under full irrigation.

Population growth in urbanizing areas such as the Front Range of Colorado has led to increased pressure to transfer water from agriculture to municipalities. In some cases, farmers may remain agriculturally productive while practicing limited or deficit irrigation, where substantial yields may be obtained with reduced water applications during non-water-sensitive growth stages, and crop evapotranspiration (ET) savings could then be leased by municipalities or other entities as desired. Site-specific crop simulation models have the potential to accurately predict yield and ET trends resulting from differences in irrigation management. The objective of this study was to statistically determine the ability of the CERES-Maize model to accurately differentiate between full and limited irrigation treatments in northeastern Colorado in terms of evapotranspiration (ET), crop growth, yield, water use efficiency (WUE), and irrigation use efficiency (IUE). Field experiments with corn were performed near Fort Collins, Colorado, from 2006 to 2008, where four replicates each of full (100% of ET requirement for an entire season) and limited (100% of ET during reproductive stage only) irrigation treatments were evaluated. Observations of soil profile water content, leaf area index, leaf number, and grain yield were used to calibrate (2007) and evaluate (2006 and 2008) the model. Additionally, ET and water use efficiency (WUE) were calculated from a field water balance and compared to model estimates. Over the three years evaluated, CERES-Maize agreed with observed trends in anthesis date, seasonal cumulative ET (Nash-Sutcliffe efficiency ENS = 0.966 for full irrigation and 0.835 for limited irrigation), leaf number in 2007 (ENS = 0.949 for full irrigation and 0.900 for limited irrigation), leaf area index in 2008 (ENS = 0.896 for full irrigation and 0.666 for limited irrigation), and yield (relative error RE = 4.1% for full irrigation and -3.4% for limited irrigation). Simulation of late-season leaf area index in limited irrigation was underestimated, indicating model overestimation of water stress. Simulated cumulative ET trends were similar to observed values, although CERES-Maize showed some tendency to underpredict for full irrigation (RE = -7.2% over all years) and overpredict for limited irrigation (RE = 12.7% over all years). Limited irrigation observations showed a significant increase in WUE over full irrigation in two of the three years; however, the model was unable to replicate these results due to underestimation of ET differences between treatments. While CERES-Maize generally agreed with observed trends for full and limited irrigation scenarios, simulation results show that the model could benefit from a more robust water stress algorithm that can accurately reproduce plant responses such as those observed in this study.

Long-term productivity of early season peach trees under different irrigation methods and postharvest deficit irrigation

Partial rootzone drying (PRD) and regulated deficit irrigation (RDI) effects on stomatal conductance, growth, photosynthetic capacity, and water-use efficiency of papaya

Irrigation and nitrogen management are crucial for sustainable potato (Solanum tuberosum L.) production. A field experiment was conducted during the 2022 and 2023 growing seasons at Farmington, New Mexico, to evaluate the performance of two chip potato varieties (Lamoka and Waneta) under three irrigation regimes (full irrigation (FI), 20% deficit irrigation (DI) and 40% DI) and seven nitrogen fertilizer rates (0, 60, 115, 170, 220, 280, and 340 kg N/ha). The treatment combinations of irrigation regimes, nitrogen rates, and varieties were arranged in a split–split plot design with three replications as main plot, sub-plot, and sub-sub plot, respectively. The two-year results showed that irrigation regimes had the most significant effect on plant growth, physiology, and tuber yield of the potato varieties. For both Lamoka and Waneta, the plant height and canopy cover were lower under 40% DI than under 20% DI and FI treatments. The SPAD meter values were higher under 40% DI, followed by 20% DI and FI treatments, whereas the stomatal conductance was higher under FI, followed by 20% DI and 40% DI during both growing seasons. Regardless of nitrogen rates and variety, a 20% water-saving irrigation strategy reduced the total tuber yield by 4.5% and 22.1% in the 2022 and 2023 growing seasons, respectively, while the 40% water-saving irrigation strategy reduced total tuber yield by 36.8% and 58.2% in the 2022 and 2023 growing seasons, respectively, as compared to full irrigation. Shifting from full irrigation to 20% DI could save 711.2 to 1036.3 m3/ha of irrigation water. For Lamoka, the highest total tuber yield was obtained with 60 kg N/ha under 20% DI and 220 kg N/ha under FI in 2022 and 2023, respectively. For Waneta, the highest total tuber yield was obtained with 115 kg N/ha under 20% DI and 170 kg N/ha under FI in 2022 and 2023, respectively. Maximum water use efficiency (WUE) was obtained at 60 kg N/ha with 20% DI for both Lamoka and Waneta in 2022, while maximum WUE was obtained at 220 kg N/ha under FI for Lamoka and at 170 kg N/ha for Waneta in the 2023 season. The maximum nitrogen use efficiency (NUE) was achieved with 60 kg N/ha under 20% DI for both varieties during both growing seasons. Thus, for sustainable irrigation and nitrogen management, the application of a 20% deficit irrigation strategy with a lower nitrogen rate (60 to 170 kg N/ha) could be the best option to improve WUE and NUE with minimal tuber yield reduction. Our study suggested that 40% deficit irrigation would not be beneficial as compared to both full irrigation and 20% water-saving irrigation.