Effect of irrigation on wild and inbred maize with relation to the antioxidant status of pollens, flag leaves, and developing grains.

The investigation was carried out to evaluate the net effect of limited irrigation on the antioxidant status of pollens, flag leaves, and developing grains of wild and inbred maize lines. Teosinte pollens showed the highest activities of superoxide dismutase (SOD), catalase (CAT), glutathione reductase (GR), glutathione-s-transferase (GST), and peroxidase (POX) under stressful conditions while LM 11 showed a significant decrease in APX, CAT, GR, and GST activities. Limited irrigations increased the contents of superoxide and malondialdehyde (MDA) to maximum levels in LM 11 leaves. The pollens, leaves, and developing grains of teosinte had the highest content of total phenols. Proline was maximum in the developing grains of teosinte and CML 32 while lowest in those of LM 11. Principal component analysis showed that LM 11 genotype and the respective antioxidant enzymes were in completely opposite quadrants. Chord analysis showed that CAT activity and total phenol content in pollens, leaves, and developing grains contributed towards most of the variations observed in teosinte and might be responsible for managing the yield attributes of genotype during stress conditions. The pollens and leaves of teosinte, with significant SOD activity, further helped in optimizing plant yield, under stressful conditions. CML 32 occupied intermediate position owing to the unaffected activities of most of the antioxidant enzymes and high content of antioxidants in its tissues. It may be concluded that the overall antioxidant status of tissues decides the tolerance behavior of plants.

Assessment of the sustainability of groundwater utilization and crop production under optimized irrigation strategies in the North China Plain under future climate change.

Over-exploitation of groundwater due to intensive irrigation and anticipated climate change pose severe threats to the water and food security worldwide, particularly in the North China Plain (NCP). Limited irrigation has been recognized as an effective way to improve crop water productivity and slow the rapid decline of groundwater levels. Whether optimized limited irrigation strategies could achieve a balance between groundwater pumping and grain production in the NCP under future climate change deserves further study. In this study, an improved Soil and Water Assessment Tool (SWAT) model was used to simulate climate change impacts on shallow groundwater levels and crop production under limited irrigation strategies to suggest optimal irrigation management practices under future climate conditions in the NCP. The simulations of eleven limited irrigation strategies for winter wheat with targeted irrigations at different growth stages and with irrigated or rainfed summer maize were compared with future business-as-usual management. Climate change impacts showed that mean wheat (maize) yield under adequate irrigation was expected to increase by 13.2% (4.9%) during the middle time period (2041-2070) and by 11.2% (4.6%) during the late time period (2071-2100) under three SSPs compared to the historical period (1971-2000). Mean decline rate of shallow groundwater level slowed by approximately 1 m a-1 during the entire future period (2041-2100) under three SSPs with a greater reduction for SSP5-8.5. The average contribution rate of future climate toward the balance of shallow groundwater pumping and replenishment was 62.9%. Based on the simulated crop yields and decline rate of shallow groundwater level under the future climate, the most appropriate limited irrigation was achieved by applying irrigation during the jointing stage of wheat with rainfed maize, which could achieve the groundwater recovery and sustainable food production.

Effects of Salicylic Acid and Macro- and Micronutrients through Foliar and Soil Applications on the Agronomic Performance, Physiological Attributes, and Water Productivity of Wheat under Normal and Limited Irrigation in Dry Climatic Conditions.

Ensuring food security with severe shortages of freshwater and drastic changes in climatic conditions in arid countries requires the urgent development of feasible and user-friendly strategies. Relatively little is known regarding the impacts of the co-application (Co-A) of salicylic acid (SA), macronutrients (Mac), and micronutrients (Mic) through foliar (F) and soil (S) application strategies on field crops under arid and semiarid climatic conditions. A two-year field experiment was designed to compare the impacts of seven (Co-A) treatments of this strategy, including a control, FSA + Mic, FSA + Mac, SSA + FMic, SSA + FSA + Mic, SSA + Mic + FSA, and SSA + Mic + FMac + Mic on the agronomic performance, physiological attributes, and water productivity (WP) of wheat under normal (NI) and limited (LMI) irrigation conditions. The results reveal that the LMI treatment caused a significant reduction in various traits related to the growth (plant height, tiller and green leaf numbers, leaf area index, and shoot dry weight), physiology (relative water content and chlorophyll pigments), and yield components (spike length, grain weight and grain numbers per spike, thousand-grain weight, and harvest index) of wheat by 11.4-47.8%, 21.8-39.8%, and 16.4-42.3%, respectively, while WP increased by 13.3% compared to the NI treatment. The different Co-A treatments have shown a 0.2-23.7%, 3.6-26.7%, 2.3-21.6%, and 12.2-25.0% increase in various traits related to growth, physiology, yield, and WP, respectively, in comparison to the control treatment. The SSA+ FSA + Mic was determined as the best treatment that achieved the best results for all studied traits under both irrigation conditions, followed by FSA + Mic and SSA + Mic + FSA under LMI in addition to FSA + Mac under NI conditions. It can be concluded that the Co-A of essential plant nutrients along with SA accomplished a feasible, profitable, and easy-to-use strategy to attenuate the negative impacts of deficit irrigation stress, along with the further improvement in the growth and production of wheat under NI conditions.

Biochar and compost from cotton residues inconsistently affect water use efficiency, nodulation, and growth of legumes under arid conditions.

There is an urgent global need to expand crop cultivation into arid and semiarid lands to guarantee food security. Thus, limited irrigation strategies and soil amendments are promising strategies for conserving water in arid and semi-arid crop production. Soil amendments, such as compost and biochar can improve soil water relationships, nitrogen (N) fixation, soil fertility, and crop productivity. A study was designed to evaluate the effect of biochar and compost applications on soil water relationships, nutrient uptake, plant growth, and N-fixation. A greenhouse pot experiment was conducted in two soils using a complete factorial design. The main effect, i.e., water content of each soil, was maintained at either 40% or 60% water filled porosity. The sub-effect, organic amendment type, was applied as biochar or compost. The sub-sub effect was rate of application (0, 5, and 10 Mg ha-1). Plant height and root length were significantly affected by the rate of amendment applied, whereas shoot and root mass differences were explained by irrigation strategy. Whole plant N uptake was moderately affected by water content only (p = 0.0818). Phosphorus and Potassium uptake were highly affected by amendment type and rate. Biochar moderately improved plant available water (0.061 %Vol Mg-1 ha-1) over the range of 0-20 Mg ha-1 in the sandier soil. Compost did not improve plant available water in either soil. Nodulation was affected by soil type only. The benefits of biochar or compost for plant were inconsistent and depended upon irrigation strategies, soil type, application rate, and plant species.

[Effects of water limiting and nitrogen reduction on nitrogen use and apparent balance of winter wheat in the Guanzhong Plain, Northwest China]. / é™æ°´å‡æ°®å¯¹å ³ä¸­å¹³åŽŸå†¬å°éº¦æ°®ç´ åˆ©ç”¨å’Œæ°®ç´ è¡¨è§‚å¹³è¡¡çš„å½±å“.

Effects of water limiting and nitrogen reduction on yield, nitrogen use efficiency and nitrogen apparent balance of wheat were investigated to explore whether it would be feasible to restrict water and reduce nitrogen in wheat production of the Guanzhong Plain and thus to provide scientific supports for yield-stable, high-efficiency, and environment-friendly developments in the irrigated production of winter wheat. Following a split-plot design with two water regimes as the main plots and four N addition rates as sub-plot factors, a field experiment (2017-2019) was conducted in Yangling, Shaanxi. The two water regimes were conventionally irrigating at the rate of 60 mm during the overwinter period and at the jointing stage, respectively (W2, a conventional practice) and irrigating at a rate of 60 mm during the overwintering period (W1, a restrictive irrigation practice). The four nitrogen addition rates were 300 kg·hm-2(N300, a conventional N rate), 225 kg·hm-2 (N225, a nitrogen rate of 25% less than the convention), 150 kg·hm-2(N150, a nitrogen rate 50% of less than the convention), and 0 kg·hm-2(N0, no nitrogen applied). The decreased irrigation rate and nitrogen rate significantly increased nitrogen content in the plants and grains, yield, N output, nitrogen use efficiency, nitrogen harvest index, nitrogen recovery efficiency, and nitrogen agronomic efficiency, reduced nitrate leaching and N surpluses, and maintained nitrogen balance. With both W1 and N150 adopted, the increased irrigation rate and nitrogen rate did not affect yield and N output of winter wheat in 2017-2019. Plant nitrogen content with both W1 and N150 adopted increased by 0.1%-25.5% and 14.0%-31.6% and the grain nitrogen content increased by 0.1% and 4.6%, compared with those with both W2 and N300 adopted in 2017-2018 and 2018-2019, respectively. Nitrogen use efficiency, nitrogen harvest index, nitrogen recovery efficiency, and nitrogen agronomic efficiency were averagely increased by 95.3%, 4.2%, 81.7% and 33.0% respectively. The N surplus was decreased by 97.2% and 95.1%, which effectively alleviated soil nitrate leaching. Considering all the indicators, irrigating at 600 m3·hm-2 during the overwintering period plus applying nitrogen at 150 kg·hm-2 could achieve high yield, high efficiency, and environment friendly development of winter wheat in the Guanzhong Plain of Shaanxi.

Foliar application of silicon boosts growth, photosynthetic leaf gas exchange, antioxidative response and resistance to limited water irrigation in sugarcane (Saccharum officinarum L.).

Plant cell and water relationship regulates morphological, physiological and biochemical characteristics to optimize carboxylation for enhanced biomass yield in sugarcane. Insufficient water irrigation is one of the serious problems to impair potential yield of agriculturally important sugarcane cash crop by loss in plant performance. Our study aims to reveal consequences of foliar spray of silicon (Si) using calcium metasilicate powder (Wollastonite, CaO.SiO2) to alleviate the adverse effects of limited water irrigation in sugarcane. Silicon (0, 50, 100 and 500 ppm) was applied as foliar spray on normally grown 45 days old sugarcane plants. Further, these plants were raised at half field capacity (50%) using water irrigation precisely up to 90 days under open environmental variables. Consequently, restricted irrigation impaired plant growth-development, leaf relative water content (%), photosynthetic pigments, SPAD unit, photosynthetic performance, chlorophyll fluorescence variable yield (Fv/Fm) and biomass yield. Notably, it has enhanced values of proline, hydrogen peroxide (H2O2), malondialdehyde (MDA), antioxidative defense enzyme molecules viz., catalase (CAT), ascorbate peroxidase (APx) and superoxide dismutase (SOD). The foliar spray of Si defended sugarcane plants from limited water irrigation stress as Si quenched harmful effect of water-deficit and also enhanced the operation of antioxidant defense machinery for improved sugarcane plant performance suitably favored stomatal dynamics for photosynthesis and plant productivity.

Effects of growth-stage-based limited irrigation management on the growth, yields, and radiation utilization efficiency of winter wheat in northwest China.

BACKGROUND: As a common abiotic stress, water deficit stress has a negative impact on the growth and yield of many field crops worldwide. In this study, a mobile rain shelter experiment was conducted in the 2017-2019 growing seasons to investigate the effects of water stress at different growth stages on various traits in winter wheat, including plant height, leaf area index (LAI), biomass, radiation use efficiency (RUE), leaf photosynthetic traits, and yield. RESULTS: Three different limited irrigation treatments were applied: no irrigation at all stages (T0), no irrigation at the reviving and jointing stages (T1), and no irrigation at the heading and grain-filling stages (T2). In all treatments, 2-year averages showed that T1 resulted in the highest grain yield (6470 kg ha-1 ). The plant height and LAI of winter wheat increased in the order of T0 < T1 < T2. In addition, T1 increased post-anthesis biomass. The net photosynthetic rate and RUE were significantly higher in T1 than in other treatments. T1 could improve leaf photosynthetic traits by increasing Gs, Fv/Fm, ΦPSII, and qP, thus increasing RUE and grain yield. CONCLUSION: We propose that irrigation at the heading and grain-filling stages was the optimal limited irrigation practice for efficient radiation use and high yields in winter wheat in the arid and semi-arid area of northwest China. © 2021 Society of Chemical Industry.

Effect of osmo priming on sucrose metabolism in spring maize, during the period of grain filling, under limited irrigation conditions.

The present study was undertaken to study the effect of osmo priming on sucrose metabolism of spring maize, under limited irrigation conditions. Osmo priming increased the activities of acid invertase, alkaline invertase and sucrose synthase (cleavage) and the contents of reducing sugars and starch in the grains of stressed plants. There was also an increase in sucrose phosphate synthase activity with a parallel increase in sucrose content in leaves of stressed plants in comparison with those of hydro priming treatment. It showed that osmo priming helped in improving sucrose phosphate synthase activity in leaves of plants, leading to higher sucrose content, under stress conditions.