The Integrative Effects of Biochar and ZnO Nanoparticles for Enhancing Rice Productivity and Water Use Efficiency under Irrigation Deficit Conditions.

Water stress is considered one of the most environmental hazards that threaten agricultural productivity. Therefore, two field experiments were conducted to investigate the impact of biochar (6 t ha-1 as soil amendment), ZnO NPs (50 mg L-1 as foliar application), and their combination on growth, yield, and water use efficiency (WUE) of rice grown under four irrigation deficit treatments (i.e., irrigation every 3, 6, 9 and 12 d). The irrigation every 3 d was considered as the control in the current study. For this purpose, biochar was prepared through the pyrolysis of corn stalk and rice husk at 350 °C for 3 h, while sonochemical combined with the precipitation method was used to prepare zinc oxide nanoparticles (ZnO NPs) from zinc acetate. The morphological structures of the produced biochar and ZnO NPs were characterized using X-ray diffraction (XRD), N2 gas adsorption-desorption, scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The results exhibited that the combination of biochar alongside ZnO NPs resulted in a positive significant effect on the physiological traits such as chlorophyll content, relative water content, plant height, and leaf area index as well as yield-associated components (i.e., number of panicles m-2, number of filled grain per panicle, 1000-grain weight), and biological and grain yield ha-1 when rice plants were irrigated every 9 days without a significant difference with those obtained from the control treatment (irrigation every 3 d). In conclusion, the combination of biochar and ZnO NPs could be recommended as an optimal approach to maximize both grain yield ha-1 and WUE of rice.

Application of Silica Nanoparticles for Improving Growth, Yield, and Enzymatic Antioxidant for the Hybrid Rice EHR1 Growing under Water Regime Conditions.

The current study was designed to assess the effect of different concentrations of silica oxide nanoparticles (SiO2NPs) (0, 30, 60, and 90 ppm) as foliar applications under three irrigation regimes i.e., irrigation every 3 days (IR3, control), irrigation every 6 days (IR6), and irrigation every 9 days (IR9) on growth, yield and certain metabolites of rice (Oryza sativa L. cv. EHR1). To achieve such a goal, 2 field experiments were conducted during the 2018 and 2019 seasons at the Experimental Farm of Rice Research and Training Center (RRTC), Sakha Agricultural Station, Kafr El-sheik, Egypt. Firstly, the as-prepared nanoparticles of SiO2 were prepared from useless materials (RHs) which are considered as one of the bio burdens on the environment via treating with HCl and followed by drying and calcination. Consequently, the synthesis was examined by making use of advanced tools such as X-ray diffraction (XRD), transmission electron microscopy (TEM), dynamic light scattering (DLS) for illustrating the hydrodynamic particle size of SiO2NPs and scanning electron microscopy (SEM). The nanoparticles were formed with nearly spherical shape and small size. The results indicated that leaf area index, dry matter production, the number of panicles/m2, the number of filled grains/ panicles, 1000 grain weight, grain yield, and biological yield as well as chlorophyll content have witnessed a significant increase under irrigated application every 3 and 6 days. Whilst a prolonged irrigation regime up to 9 days recorded a remarkable decline in the aforementioned characteristics except for the number of unfilled grains/panicle which increased considerably in both seasons. On the other hand, proline concentration and the activity of the antioxidant enzymes were increased in both irrigated treatments every 6 and 9 days compared with control treatment (irrigation every 3 days). The foliar supplementations of (SiO2NPs) contributed to ameliorating all the aforementioned characteristics progressively up to the dosage of 90 ppm compared to control treatment (no Si/NPS application) in both seasons. Invariably, growth and yield parameters in water-stressed plants treated with SiO2NPs were higher than those in water-stressed plants without SiO2NPs addition. Based on that, it could be concluded that the foliar application of SiO2NPs can mitigate the adverse effect of water stress on rice plants.

Green Synthesis of Zinc Oxide Nanoparticles: Fortification for Rice Grain Yield and Nutrients Uptake Enhancement.

Applications of metal oxide nanoparticles in the agriculture sector are being extensively included as the materials are considered superior. In the present work, zinc oxide nanoparticle (ZnO NPs), with a developing fertilizer, is applied in the fortification of rice grain yield and nutrient uptake enhancement. To evaluate the role of ZnO NP, two field experiments were conducted during the 2018 and 2019 seasons. ZnO NPs were small, nearly spherical, and their sizes equal to 31.4 nm, as proved via the dynamic light scattering technique. ZnO NPs were applied as a fertilizer in different concentrations, varying between 20 and 60 mg/L as a foliar spray. The mixture of ZnSO4 and ZnO NP40 ameliorated yield component and nutrients (N, K, and Zn) uptake was enhanced compared to traditional ZnSO4 treatment. Nevertheless, the uptake of the phosphorous element (P) was adversely affected by the treatment of ZnO NPs. Thus, treatment via utilizing ZnO NPs as a foliar with a very small amount (40 ppm) with of basal ZnSO4 led to a good improvement in agronomic and physiological features; eventually, higher yield and nutrient-enriched rice grain were obtained.