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 (ET_c), 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 ET_c play the main role in drought stress avoidance mechanisms in grapevines raised under moderate deficit irrigation conditions.

The biochar application can improve the physiochemical properties of both sandy and clayey loam soils and is considered a potential adaptation tool toward climate change. Therefore, the current study is novel in combining water-hyacinth-derived biochar with organic manures as a suggested effective way of treating the soil with biochar under arid and semiarid conditions. Water hyacinth weeds were slow pyrolyzed at a temperature of 300 °C, which resulted in nonalkaline biochar with a pH value of 6.31, which is suitable for alkaline soils. A pot experiment was established to study the impact of the solo application of nonalkaline water-hyacinth-derived biochar (WHB) and its combined application with farmyard (WHB/FM) and poultry manure (WHB/PM) at a rate of 1.5 and 3%, respectively, on some chemical and physical properties of sandy and clay loam soils and some barley’s growth parameters. WHB, WHB/FM, and WHB/PM significantly affected the soil pH at different application rates (1.5 and 3%) in sandy soil. A considerable alteration in water-stable aggregates (WSA), dispersion ratio (DR), available water content (AWC), and cation ratio of soil structural stability (CROSS) index resulted from combining manures (FM and PM) with biochar better than the solo application of biochar. WHB/PM treatments had a superior effect in improving barley’s growth. Relative increases were by 37.3 and 11.0% in plant height and by 61.6 and 28.5% in the dry matter in sandy and clayey loam soils, respectively. Under the conditions of this study, we can conclude that treating the soil with WHB/PM at a rate of 1.5 and 3% is the most effective application. The current study may have a vital role in Egyptian agriculture sustainability by enhancing the soil characteristics of the old agricultural and the newly reclaimed lands.

Drought stress is a group of abiotic stresses that affects plant growth and yield production. A field experiment over two successive seasons (2021–2022 and 2022–2023) in sand soil was conducted to investigate the integration effect of deficit irrigation, soil amendment “hundzsoil”, and the spraying of proline on the water use efficiency (WUE), yield, and fruit quality of 8-year-old Crimson seedless table grapes. Four application rates of soil amendment (0, 2, 4, and 6 kg hundzsoil /vine) were added during the dormancy period, and four irrigation levels at 125, 100, 75, and 60% of the field capacity were applied just before flowering until harvest. Proline at two levels (0 and 500 ppm) was applied as a foliar spray. Parameters such as bud fertility, weight of 100 berries, juice volume, and cluster number were positively affected by irrigation at 75% FC along with applying hundzsoil at 2 and 4 kg/vine under proline spray in both seasons. Irrigation at the 125% FC level with a 6 kg hundzsoil application under proline spray resulted in the highest yield, berries number, cluster length, cluster weight, and total anthocyanin in both seasons. The TSS/acidity ratio was significantly and positively affected by deficit irrigation (60% FC level) under hundzsoil at a rate of 4 kg alongside proline spray. Reducing irrigation to 60% FC without hundzsoil and proline spray negatively affected numerous growth parameters and the yield. However, irrigation at 60% FC alongside 6 kg of hundzsoil and proline showed the highest IWUE in both seasons. Proline spray was a key factor in conserving water used for irrigation. This study recommends using deficit irrigation alongside hundzsoil application under proline spray as an adequate strategy for water use efficiency and improving the yield and fruit quality of Crimson seedless grapevines cultivated in sand soil.

Wheat is one of the most important cereal crops in Egypt and all over the world. Its productivity is adversely affected by drought due to deficient irrigation to provide nutrients required for plant growth. In a field experiment, silicon foliar applications at concentrations of 0, 200, and 400 mg L⁻¹ were performed at different irrigation rates ranging from 1000 to 4000 m³ ha⁻¹ to assess water irrigation productivity and wheat crop yield in a calcareous soil under arid climate conditions. Increased irrigation rates led to a significant increase in soil nutrient dynamics, as well as in the number and weight of grains per spike, leaf area index, grain yield, straw yield, and biological yield, with the exception of the weight of 1000 grains. Spraying with sodium silicate had a significant impact on grain yield and harvest index but did not significantly impact the other traits. Furthermore, the interaction between irrigation and silicate application rates showed significance only for grain yield, the number of spikes/m², and the harvest index. Applying three times irrigation could produce the highest nutrient retention, wheat yield, and water irrigation productivity. No significance was observed between 3000 m³ ha⁻¹ and 4000 m³ ha⁻¹ irrigation, indicating a saving of 25% of applied irrigation water. It can be concluded that applying irrigation at 3000 m³ ha⁻¹ could be a supplemental irrigation strategy. High wheat grain yield can be achieved under deficit irrigation (3000 m³ ha⁻¹) on the northwestern coast of Egypt with an arid climate by spraying crops with sodium silicate at a rate of 400 mg L⁻¹.

The use of saline water in agriculture is increasing these decades due to the scarcity of fresh water. The use of silicon nanoparticles is a new approach that can alleviate the adverse effect of saline water on plant growth. The current study was carried out to evaluate the impact of silicon nanoparticles (BSNPs) under salinity stress on seed germination and seedling growth parameters of faba bean (Vicia Faba L.) seedling. The research investigated the interaction between six BSNPs (0, 1500, 3000, 4500, 6000, and 7500 mgL-1) and five salinity levels (freshwater: seawater) (0.70, 1.1, 1.6, 2.1, and 3.1 dSm-1). The results revealed a significant decrease in the germination percentage (GP) with increasing salinity levels for the seeds primed in freshwater than that primed in fresh water and BSNPs. Salinity adversely affected the length of the faba bean radicle for seeds priming in freshwater or in fresh water and BSNPs. This was more noticeable for the seeds primed in freshwater than the seeds primed in BSNPs at high salinity levels. The priming in BSNPs significantly reduced the radius of the root seedlings and the priming in 7500 mgL-1 gave the lowest value for the radius of the radicle. The Increase in salinity levels decreased the total biomass of faba bean for seeds primed in fresh water, contrary to seeds primed in BSNPs. Vigor and salt tolerance indices were significantly affected by levels of salinity, BSNP treatments, and interactions.

Nickel (Ni⁺²) accumulation in wastewater treatment sludge poses a potential environmental risk with biosolids-land application. An incubation experiment was conducted to evaluate the effect of nanoparticles of zero-valent iron (nZVI) on Ni⁺² sorption in biosolids-treated agricultural soils. Two application rates of biosolids (0, 5%, w/w) and four treatment levels (0, 1, 5, and 10 g/kg) of nZVI were examined, either separately or interactively. The results of this study showed significant differences in Ni⁺² sorption capacity between different nZVI treatments. The initial Ni⁺² concentration in biosolids-amended soil significantly affected Ni sorption in the soil treated with nZVI. The “H-shape” of sorption isotherm in nZVI-treated soil reflects strong interaction between the Ni concentration and the nZVI treatment, while the C-shape of sorption isotherm in biosolids-amended soil without the nZVI treatment indicates intermediate affinity for Ni⁺² sorption. Nickel retention in soil was increased with the increase of nZVI levels. The removal efficiency of Ni⁺² by nZVI from solution was increased with the increase of pH from 5 to 11 and reached a maximum of 99.56% at pH 11 and nZVI treatment of 10 g/kg. The Ni⁺² desorption rate decreased from 92 to 7, 4, and 1% with increasing nZVI treatment levels from 0 to 1, 5, and 10 g/kg, respectively, with a soil Ni⁺² concentration of 50 mg/L. The maximum adsorption capacity (q_max) of 10 g/kg nZVI-treated soil was 333.3 mg/g, which was much higher than those from the other treatments of 0 (5 mg/g), 1 (25 mg/g), and 5 g/kg (125 mg/g). The underlying mechanism for Ni⁺² immobilization using nZVI in an aquatic environment is controlled by a sorption process, reduction of metal ion to zero-valent metal, as well as (co)precipitation. Moreover, increasing the nZVI treatment level in biosolids-amended soil significantly decreased bioavailable Ni⁺² concentrations in the soil.