The impact of biochar and chitosan on barley plants under drought stress conditions was investigated during two field experiments. Our results confirmed that drought stress negatively affected morphological and physiological growth traits of barley plants such as plant height, number of leaves, chlorophyll concentrations, and relative water content. However, electrolyte leakage (EL%), lipid peroxidation (MDA), soluble sugars, sucrose and starch contents significantly increased as a response to drought stress. Additionally, 1000 grain weight, grains yield ha−1 and biological yield significantly decreased in stressed barley plants, also anatomical traits such as upper epidermis, lower epidermis, lamina, and mesophyll tissue thickness as well as vascular bundle diameter of flag leaves significantly decreased compared with control. The use of biochar and chitosan led to significant increases in plant height, number of leaves, and chlorophyll concentrations as well as relative water content; nevertheless these treatments led to significant decreases in electrolyte leakage (EL%) and lipid peroxidation (MDA) in the stressed plants. Moreover, anatomical and yield characters of stressed barley plants were improved with application of biochar and chitosan. The results proved the significance of biochar and chitosan in alleviating the damaging impacts of drought on barley plants.

Environmental stressors negatively affect crop growth and yield. Limited information is available about the synergistic use of biochar and plant growth-promoting rhizobacteria (PGPR). A field study was conducted to evaluate the effect of biochar in combination with PGPR (Pseudomonas koreensis and Bacillus coagulans) for alleviating water deficit and saline soil in rice (Oryza sativa L.). Two growing seasons, 2017 and 2018, were examined using twelve combinations of three irrigation intervals every 6 days (I1), 8 days (I2), and 10 days (I3) and four soil treatments (control, PGPR, biochar, and combination of PGPR + biochar) in salt-affected soil. The findings exhibited that synergistic use of biochar and PGPR alleviated the negative effect of these stressors. The integrative use of biochar and PGPR caused an increment in soil moisture content and physicochemical properties. Significant increasing in chlorophyll content, relative water content, stomatal conductance, K+ and K+/Na+ contents occurred with decreasing proline content and Na+ content, which confirmed the efficacy of this approach. As a result, the highest yield and its related traits were attained when biochar and PGPR were added together under irrigation interval I1, which was on par with I2. We concluded that increased nutrients uptake (N, P, and K) were the cause of the superior rice productivity resulting from co-PGPR biochar. Synergistic use of biochar and PGPR could be an effective strategy for improving plant growth and productivity under stressors.

Drought stress deleteriously affects growth, development and productivity in plants. So, we examined the silicon effect (2 mmol) and proline (10 mmol) individually or the combination (Si + proline) in alleviating the harmful effect of drought on total phenolic compounds, reactive oxygen species (ROS), chlorophyll concentration and antioxidant enzymes as well as yield parameters of drought-stressed sugar beet plants during 2018/2019 and 2019/2020 seasons. Our findings indicated that the root diameter and length (cm), root and shoot fresh weights (g plant−1) as well as root and sugar yield significantly decreased in sugar beet plants under drought. Relative water content (RWC), nitrogen (N), phosphorus (P) and potassium (K) contents and chlorophyll (Chl) concentration considerably reduced in stressed sugar beet plants that compared with control in both seasons. Nonetheless, lipid peroxidation (MDA), electrolyte leakage (EL), hydrogen peroxide (H2O2) and superoxide (O2●−) considerably elevated as signals of drought. Drought-stressed sugar beet plants showed an increase in proline accumulation, total phenolic compounds and up-regulation of antioxidant enzymes catalase (CAT) and superoxide dismutase (SOD) activity to mitigate drought effects. Si and proline individually or the combination Si + proline considerably increased root and sugar yield, sucrose%, Chl concentration and RWC, MDA and EL were remarkably reduced. The treatments led to adjust proline and total phenolic compounds as well as CAT and SOD activity in stressed sugar beet plants. We concluded that application of Si + proline under drought stress led to improve the resistance of sugar beet by regulating of proline, antioxidant enzymes, phenolic compounds and improving RWC, Chl concentration and Nitrogen, Phosphorus and Potassium (NPK) contents as well as yield parameters.

Flax is a potential winter crop for Egypt that can be grown for both seed and fiber. The study was conducted during two successive winter seasons of 2013/14 and 2014/15 in the experimental farm of El-Gemmeiza Agricultural Research Station, Agriculture Research Centre, Egypt. The objective of this work was to evaluate the effect of irrigation intervals (25, 35 and 45) on the straw, seed, oil, fiber yields and quality of flax cultivars (Sakha1, Giza9 and Giza10). Irrigation intervals significantly influenced all studied traits except oil percentage. Irrigated flax plants every 35 days gave the maximum values for all traits, while irrigation every 45 days gave the minimum values. In respect to cultivars, significant differences were found in most yield and quality characters. Furthermore, the performance of Sakha 1 cultivar was superior in main stem diameter, biological, straw yields per faddan, seed index, seed, oil yields per faddan and oil percentage. Meanwhile, Giza 10 cultivar highly significantly out yielded Giza9 and Sakha1 in plant height, fiber fineness, fiber length, total fiber percentage and fiber yield per faddan. The interactions between irrigation intervals and flax cultivars were highly significant for all traits. Based on the results, Sakha1 cultivar recorded the maximum values for main stem diameter, biological, straw yields per faddan, seed, oil yields per faddan and oil percentage and Giza 10 recorded the maximum values for plant height, fiber fineness, fiber length, total fiber percentage and fiber yield per faddan under irrigation of plants every 35 days.

Given the expectancy of the water supply becoming scarce in the future and more expensive, water conservation during wheat production processes has become very crucial especially in saline sodic soil. Biochar and salicylic acid (SA) were used to assess the potential to alleviate the influences of depletion of available soil moisture (DAM) on physicochemical, physiological, biochemical attributes, as well as wheat production absorption (Triticum aestivum L. cv. Misr 1) and macro-elements. Two seasons (2018/2019 and 2019/2020) of field trials were investigated using twelve combinations of three water treatments (50%, 70%, and 90% DAM) and foliar- and soil-applied treatments (control, biochar, salicylic acid, and biochar + SA). Biochar treated plots amplified soil physicochemical attributes, leading to improved physiological traits and antioxidant enzymes, as well as yield related traits under water limitation conditions in both years. Similarly, synergistic use of biochar and salicylic acid greatly augmented the designed characteristics such as chlorophyll a, b, K+ content, relative water content (RWC), stomatal conductance, photosynthetic rate, and intrinsic water use efficiency, whilst exhibited inhibitory effects on proline content, electrolyte leakage, Na+ content SOD, POX, CAT, and MDA, consequently increased 1000-grain weight, number of grains spike−1, grain yield, as well nutrient uptake (N, P, K) under water limitation condition in both years, followed by treatment of sole biochar or SA compared to unamended plots treatment (control). Wheat productivity achieved further increasing at 70% DAM alongside synergistic use of biochar and SA which was on par with 50% DAM under unamended plots (control). It is concluded from the findings that coupled application of biochar alongside salicylic acid accomplished an efficient approach to mitigate the injurious influences of water limitation, along with further improvement of the soil, physiology, biochemical attributes, and wheat yield, as well nutrient uptake, under saline sodic soil.

Plant growth and crop productivity under unfavorable environmental challenges require a unique strategy to scavenge the severely negative impacts of these challenges such as soil salinity and water stress. Compost and plant growth-promoting rhizobacteria (PGPR) have many beneficial impacts, particularly in plants exposed to different types of stress. Therefore, a field experiment during two successive seasons was conducted to investigate the impact of compost and PGPR either separately or in a combination on exchangeable sodium percentage (ESP), soil enzymes (urease and dehydrogenase), wheat physiology, antioxidant defense system, growth, and productivity under deficient irrigation and soil salinity conditions. Our findings showed that exposure of wheat plants to deficit irrigation in salt-affected soil inhibited wheat growth and development, and eventually reduced crop productivity. However, these injurious impacts were diminished after soil amendment using the combined application of compost and PGPR. This combined application enhanced soil urease and dehydrogenase, ion selectivity, chlorophylls, carotenoids, stomatal conductance, and the relative water content (RWC) whilst reducing ESP, proline content, which eventually increased the yield-related traits of wheat plants under deficient irrigation conditions. Moreover, the coupled application of compost and PGPR reduced the uptake of Na and resulted in an increment in superoxide dismutase (SOD), catalase (CAT), and peroxidase (POX) activities that lessened oxidative damage and improved the nutrient uptake (N, P, and K) of deficiently irrigated wheat plants under soil salinity. It was concluded that to protect wheat plants from environmental stressors, such as water stress and soil salinity, co-application of compost with PGPR was found to be effective.

TWO FIELD experiments were carried out at Zarzoura, Itay El-Baroud, Agricultural Research Station, El-Behaira Governorate, Agricultural Research Center (ARC), Egypt during 2014 and 2015 seasons to study the effects of three nitrogen fertilizer levels on yield and yield components under two intercropping soybean/maize patterns. The results indicated that, the highest ear length, ear diameter, No. of rows per ear, grain yield per ear (for maize), seed yield per fad (for soybean) and the better (the lowest) competitive ratio values were found with treatment intercropping patterns 2 maize: 4 soybean (CP2). While the highest grain yield per fad (for maize), No. of pods per plant, seed yield per plant (for soybean), total LER (land equivalent ratio), the percentage land saved, total AYL (actual yield loss) and WUE (water use efficiency) values were occurred under intercropping patterns 2 maize: 2 soybean (CP1).

Onion seed cv. Giza 6 " Improved " was treated with priming in salicylic acid, fungicide vitavax and salicylic acid + fungicide vitavax before packing in cloth, aluminum foil and polyethylene bags for 0, 3, 6, 9 and 12 month, after treatment. Seed moisture content %, germination %, seed and seedling vigor traits and fungi infestation% were recorded after each storage period. Seed treatments maintained onion seed quality as measured by; seed germination%, tetrazolium test, seed vigor (germination% after accelerated aging test and electrical conductivity, seedling vigor (seedling length and seedling dry weight) and fungi infection% comparing untreated seeds. Type of seed packing materials significantly affected seed moisture content and quality traits of onion seed. Aluminum foil and polyethylene bags maintained onion seed at low moisture content, fungi infestation, high seed and seedling vigor comparing cloth bags. Prolong storage periods from 0 to 3, 6, 9 and 12 months decreased germination%, viable seed, accelerated aging test%, seedling vigor traits and fungi infestation%. Treating onion seed by salicylic acid solution, fungicide vitavax and salicylic acid solution+ fungicide vitavax before storage in aluminum foil or polyethylene bag maintained onion seed germination %, seed and seedling vigor comparing untreated seed stored in cloth bags. This study suggested that, onion seed should be treated by fungicide vitavax before storage in aluminum foil to maintain onion seed quality during storage and get high field emergence.