Does brassinosteroid mitigate salt stress in sorghum?

In semi-arid regions, the use of brackish water for irrigation can reduce crop yields. However, the use of mineral fertilizer has been tested to mitigate salt stress. In this context, the objective was to evaluate the effect of salt stress at different phenological stages on the yield of peanut under potassium fertilization. The experiment was carried out from August to November 2021, in the experimental area of the Universidade da Integração da Lusofonia Afro-Brasileira (UNILAB), Redenção, Ceará, Brazil. The experimental design was completely randomized (CRD), in a 6 × 3 factorial scheme, with 6 replicates. Six strategies of irrigation with brackish water were applied from the following stages: vegetative (S1); flowering (S2); gynophore appearance (S3); pod formation (S4); fruiting (S5) and without salt stress (S6), and three doses of potassium: 0, 50 and 100% of the recommended dose. The use of brackish water in the vegetative stage led to lower pod length, pod mass, number of pods, number of marketable pods and yield. The dose corresponding to 100% of the recommended potassium dose mitigated salt stress in the pod formation and flowering stages, promoting a greater number of marketable pods, number of non-marketable pods, total number of pods and pod mass. The use of water with lower salinity throughout the cycle promoted greater pod mass, number of marketable pods and yield.

The present study used a hydroponic system with leveled channels, in order to evaluate coriander cultivation under different intervals of nutrient solution recirculation and the use of freshwater and brackish water. The experiment was carried out in a randomized block design with five replicates, in a 2 x 4 factorial scheme, from February to March 2014. Two levels of electrical conductivity (EC) of water (0.32 and 4.91 dS m-1) and four frequencies of nutrient solution recirculation (at intervals of 0.25, 2, 4 and 8 h) were evaluated. This experimental design was adopted in the evaluations performed at 10, 15 and 25 days after transplantation (DAT). Additionally, at 21 DAT subplots were established for the evaluation of plant position (initial, intermediate and final) along the hydroponic channels. It is viable to use nutrient solution recirculation every 8 h, without production losses. The use of brackish water (EC = 4.91 dS m-1) may be an alternative for the hydroponic cultivation of coriander, despite the reduction in production, but without any damage on the visual aspect of the product. Plants grown at the initial and intermediate positions along the hydroponic channels showed higher production.

Underground water reserves in the semi-arid region of Brazil are stored in the crystal formations that in large part have high concentrations of salt. However, the scarcity of this resource makes the use of this water necessary for various activities, including agriculture. The aim of this study was to evaluate the use of brackish water on the electrical conductivity and pH of the nutrient solution, and on the production, water consumption and the uptake of nutrients in Chinese cabbage (Brassica pekinensis L.) under a hydroponic system. The experimental design was completely randomised, with four replications and six levels of water salinity (0.2, 1.2, 2.2, 3.2, 4.2 and 5.2 dS m-1), obtained by adding NaCl to the local water supply, with this water being used to prepare the nutrient solution and to make up the volume lost through evapotranspiration. The results showed that with the exception of the treatment at the lowest salinity, there was a tendency to increased electrical conductivity of the nutrient solution with the increasing salinity of the water; that the pH of the nutrient solution remained within the normal range throughout the cycle; that with the increasing salinity of the solution there was a reduction in all growth and production variables under analysis, in water consumption, and in leaf N, K, Ca and Mg, and an increase in leaf concentrations of Na and Cl. It is possible to use brackish water for the production of Chinese cabbage when grown hydroponically as an alternative for those producers who have an available supply of brackish water and a restricted supply of fresh water, however with a reduction in productivity.

Effects of timing and duration of brackish irrigation water on fruit yield and quality of late summer melons

Semi-arid regions present the inherent problem of accumulation of salts in the soil due to the use of brackish water for irrigation, and water deficit compromises the growth and physiological indices of crops. This study evaluated the effect of salt and water stress on growth and gas exchange in the zucchini cv. Caserta crop. The study was conducted at the University of International Integration of Afro-Brazilian Lusophony, Redenção, Ceará State, Brazil. The experimental design was completely randomized, in a 5 × 2 factorial scheme with five levels of electrical conductivity of the irrigation water - ECw (0.5, 1.0, 1.5, 2.0, and 2.5 dS m-1) and two water regimes (50 and 100% of the potential crop evapotranspiration - ETc), with five replicates. At 36 days after sowing, the following traits were evaluated: CO2 assimilation rate, transpiration, stomatal conductance, internal carbon concentration, leaf temperature, relative chlorophyll index, and water use efficiency. At 45 days after sowing, the plant height, stem diameter, number of leaves, and leaf area were also evaluated. The use of brackish water (1 to 2.5 dS m-1) reduced the growth parameters of zucchini cv. Caserta. The increase in ECw caused a decline in the physiological traits. Under 100% ETc, higher values of CO2 assimilation rate, transpiration, and instantaneous water use efficiency were recorded, and there was 50% ETc for internal carbon concentration, even with the increase in ECw.

The use of brackish water in hydroponic crops represents an alternative for vegetable production. In this context, two experiments were conducted to evaluate the effect of using brackish water to prepare the nutrient solution and replace the evapotranspired depth, applied at different flow rates, on cauliflower biometrics in NFT (nutrient film technique) hydroponic system. In both experiments, the experimental design was completely randomized with four repetitions, in a 6 x 2 factorial scheme: six levels of water electrical conductivity (ECw) in interaction with two flow rates of nutrient solution application in the hydroponic channels (1.5 and 2.5 L min-1). In Experiment I, brackish waters with different EC (1.5, 2.5, 3.5, 4.5 and 5.5 dS m-1), obtained by the addition of NaCl in public-supply water (0.2 dS m-1), were used. In Experiment II, the chemical characteristics of brackish waters collected in the semiarid region of Pernambuco were simulated, with EC of 1.67, 3.30, 4.71, 5.88 and 13.84 dS m-1, plus the control (0.2 dS m-1). Increasing salinity reduced cauliflower growth. Flow rate of 1.5 L min-1 promoted the best results of shoot fresh and dry masses, leaf area, number of leaves, plant height and shoot diameter. The best water for cauliflower production was public-supply water and, among the well waters, the best was the calcium sulfate-rich water with EC of 1.67 dS m-1.

Development and Evaluation of a Model for Yield Production of Wheat, Maize and Sugarbeet under Water and Salt Stresses

Assessment of wheat productivity responses and soil health dynamics under brackish ground water

Salt and drought are documented among the most detrimental and persistent abiotic stresses for crop production. Here, we investigated the impact of Pseudomonas koreensis strain S4T10 on plant performance under salt and drought stress. Arabidopsis thaliana Col-0 wild type and atnced3 mutant plants were inoculated with P. koreensis or tap water and exposed to NaCl (100 mM) for five days and drought stress by withholding water for seven days. P. koreensis significantly enhanced plant biomass and photosynthetic pigments under salt and drought stress conditions. Moreover, P. koreensis activated the antioxidant defence by modulating glutathione (GSH), superoxide dismutase (SOD), peroxidase (POD), and polyphenol oxidase (PPO) activities to scavenge the reactive oxygen species produced due to the stress. In addition, the application of P. koreensis upregulated the expression of genes associated with antioxidant responses, such as AtCAT1, AtCAT3, and AtSOD. Similarly, genes linked to salt stress, such as AtSOS1, AtSOS2, AtSOS3, AtNHX1, and AtHKT1, were also upregulated, affirming the positive role of P. koreensis S4T10 in streamlining the cellular influx and efflux transport systems during salt stress. Likewise, the PGPB inoculation was observed to regulate the expression of drought-responsive genes AtDREB2A, AtDREB2B, and ABA-responsive genes AtAO3, AtABA3 indicating that S4T10 enhanced drought tolerance via modulation of the ABA pathway. The results of this study affirm that P. koreensis S4T10 could be further developed as a biofertilizer to mitigate salt and drought stress at the same time.

Water scarcity is tightening its grip on global agriculture as climate change advances, with the Mediterranean facing particular strain. About thirty percent of its 11.32 million hectares of irrigated land overlies saline aquifers, forcing farmers to depend on water of declining quality. Brackish water represents a viable substitute for freshwater, yet its adoption remains limited because current tools for assessing crop specific impacts often require detailed field measurements that are rarely available at regional scale. This study presents a simplified agro hydrological modelling framework designed for first level analysis of salinity effects on crops, soil, and irrigation demand. It operates with a small collection of standard inputs, including climate, soil properties, and irrigation water salinity, allowing consistent application across large areas. The framework is applied to twenty four crops across the Mediterranean under four irrigation strategies: freshwater baseline, brackish water only, brackish water with leaching, and mixed irrigation adjusted to maintain soil salinity at half of each crop’s tolerance level. Across regions influenced by saline aquifers, the leaching based strategy cuts freshwater use by seventy six percent compared with the freshwater baseline, while still maintaining soil salinity within acceptable crop thresholds. At the basin scale, mixed irrigation shows a total water demand of 33.68 cubic kilometres per year with limited salinity stress, providing an effective balance between freshwater conservation and soil protection. Field-level simulations for the Zelba area in Tunisia, using brackish water of 7.2 dS per metre for wheat, barley, and sorghum, confirm the strong performance of management strategies that pair brackish water with targeted leaching. This scalable approach provides rapid and reliable insight into the feasibility of brackish water use, helping farmers and policymakers evaluate irrigation options, protect soil quality, and plan freshwater savings in water-scarce environments.

The brackish water is an important potential water source and has frequently been utilized to drip-irrigate cotton due to the water shortage in the arid region of Xinjiang, northwestern of China. The brackish water is usually saline water with salinity ranging from 1 g/L to 5 g/L, which is widely distributed in this area, so the reasonable use of that brackish water may not only play a vital role in the local agricultural production, but also save plenty of freshwater. However, irrigation with brackish water usually causes the reduction of crop yield and soil salinization which can negatively impact plants through three major components: osmotic, nutritious and toxic stresses. Therefore, a field experiment, with eight different time-series irrigation modes using brackish water (3.5±0.2) g/L and freshwater, less than 1 g/L, beneath a combined film and drip-irrigation system was carried out to study the changes of soil salt content and cotton yield aiming to search for a balanced method during the 2 cotton growing seasons in 2012 and 2013. The results indicated that the time-series irrigation modes determined the soil salinity and moisture distribution based on observed spatio-temporal distribution of water content and electric conductivity, and soil salinity generally gathered at the depth of 0-10 cm and 60 cm of soil with the increase of irrigation quota. Moreover, the results demonstrated that the yields of cotton which was grown using brackish water and freshwater were better than those only using freshwater and the soil salinity with reasonable irrigation timing was not accumulated obviously. Keywords: brackish water, mulch drip irrigation, timing and duration for irrigation, irrigation scheduling, cotton DOI: 10.25165/j.ijabe.20171006.3108 Citation: Wang C X, Yang G, Li J F, He X L, Xue L Q, Long A H. Effects of timing and duration under brackish water mulch drip irrigation on cotton yield in northern Xinjiang, China. Int J Agric & Biol Eng, 2017; 10(6): 115–122.

Hydrogen peroxide (H2O2) can be indicated as a strategy to mitigate salt stress in plants, so the objective of this study was to evaluate the effect of different concentrations and methods of application of H2O2 as a mitigator of salt stress on the growth, physiology, and quality of seedlings of yellow passion fruit. The experiment was carried out in a protected environment (screened) belonging to UFERSA, in Caraúbas - RN, Brazil, in a randomized block design and analyzed in a 2 × 4 × 3 factorial scheme, with four replications and one plant per plot. The treatments consisted of levels of electrical conductivity of irrigation water - ECw (0.5 and 3.2 dS m-1), H2O2 concentrations (0, 12, 24, and 36 μM), and H2O2 application methods (M1 = seed soaking, M2 = foliar spraying, and M3 = seed soaking + foliar spraying). Increased levels of salinity in irrigation water negatively affect seedling quality. Hydrogen peroxide at an average concentration of 24 µM mitigates salt stress in passion fruit seedlings cv. BRS Gigante Amarelo. H2O2 application to seeds associated with foliar spraying mitigates the effects of salt stress on the absolute growth rate of the leaf area of passion fruit seedlings irrigated with an ECw of 3.2 dS m-1.

Sunflower is a major oil seed crop worldwide, and it is also an important crop in Mediterranean areas where salinity is an increasing problem. In this paper, the effect of saline irrigation water on seed yield and quality of sunflower was evaluated. A pot experiment was carried out over two crop seasons on two hybrids – a standard one (Carlos) and a high oleic one (Tenor) – submitted to five salinity levels of irrigation water (0.6, 3, 6, 9 and 12 dS m−1). Soil salinity was monitored over the entire crop cycle, and leaf ion content was determined at maturity. Tenor showed higher Na+and Mg2+content but lower K+values. No difference between the two hybrids was observed for Cl−content. A progressive increase in leaf Na+, K+and Cl−contents and Na+/K+ratio with increasing salinity level was observed. Seed weight per head, 1000 achene weight, number of seeds per plant and oil yield significantly decreased under salt stress in both hybrids. The percent seed yield decrease was higher per unit increase in electrical conductivity of irrigation water, ECw (8%), than per unit increase in electrical conductivity of saturated‐soil extracts, ECe (5%). Concerning oil fatty acid composition, the main significant difference as result of salt stress was a progressive increase in oleic acid content, from 82.2% to 86.7% for Tenor and from 21.8% to 27.3% for Carlos, which was consistent with a decrease in linoleic acid content, from 5.9% to 3% for Tenor and from 66% to 61.3% for Carlos. These results confirm the possible inhibition of oleate desaturase under salt stress.

Combined use of seaweed extract and arbuscular mycorrhizal fungi for alleviating salt stress in bell pepper (Capsicum annuum L.)

In this paper, winter wheat was used as the research object. The chlorophyll content, net photosynthetic rate, light response curve and yield of winter wheat were compared with the experimental data from 2015 to 2017.The results show that:The brackish water of 3g/L has little effect on chlorophyll content. The physiological growth of winter wheat could be promoted by irrigation with 3 g/L brackish water at jointing stage, and photosynthesis could be promoted by appropriate salt stress. Salt stress can change the way crops use effective light radiation. The brackish water of 3g/L can promote the utilization efficiency of low effective light radiation in winter wheat. The brackish water of 5g/l will affect the leaf structure of winter wheat, reduce the response of leaves to high effective light radiation, and eventually lead to the decline of photosynthesis. Two years of brackish water irrigation will have a certain effect on crop yield.