Incorporated Biochar-Based Soil Amendment and Exogenous Glycine Betaine Foliar Application Ameliorate Rice (Oryza sativa L.) Tolerance and Resilience to Osmotic Stress

Osmotic stress is a major physiologic dysfunction that alters the water movement across the cell membrane. Soil salinity and water stress are major causal factors of osmotic stress that severely affect agricultural productivity and sustainability. Herein, we suggested and evaluated the impact of integrated biochar-based soil amendment and exogenous glycine betaine application on the growth, physiology, productivity, grain quality, and osmotic stress tolerance of rice (Oryza sativa L., cv. Sakha 105) grown in salt-affected soil under three irrigation intervals (6, 9, or 12 days), as well as soil properties and nutrient uptake under field conditions during the 2019 and 2020 seasons. Our findings showed that dual application of biochar and glycine betaine (biochar + glycine betaine) reduced the soil pH, electrical conductivity, and exchangeable sodium percentage. However, it enhanced the K+ uptake which increased in the leaves of treated-rice plants. Additionally, biochar and glycine betaine supplementation enhanced the photosynthetic pigments (chlorophyll a, b, and carotenoids) and physiological attributes (net photosynthetic rate, stomatal conductance, relative water content, and electrolyte leakage) of osmotic-stressed rice plants. Biochar + glycine betaine altered the activity of antioxidant-related enzymes (catalase, ascorbate peroxide, and peroxidase). Moreover, it improved the yield components, biological yield, and harvest index, as well as the nutrient value of rice grains of osmotic-stressed rice plants. Collectively, these findings underline the potential application of biochar and glycine betaine as a sustainable eco-friendly strategy to improve plant resilience, not only rice, but other plant species in general and other cereal crops in particular, to abiotic stress, particularly those growing in salt-affected soil.

Interactive Impacts of Beneficial Microbes and Si-Zn Nanocomposite on Growth and Productivity of Soybean Subjected to Water Deficit under Salt-Affected Soil Conditions

Water stress or soil salinity is considered the major environmental factor affecting plant growth. When both challenges are present, the soil becomes infertile, limiting plant productivity. In this work a field experiment was conducted during the summer 2019 and 2020 seasons to evaluate whether plant growth-promoting microbes (PGPMs) and nanoparticles (Si-ZnNPs) have the potential to maintain soybean growth, productivity, and seed quality under different watering intervals (every 11 (IW0), 15 (IW1) and 19 (IW2) days) in salt-affected soil. The most extended watering intervals (IW1 and IW2) caused significant increases in Na+ content, and oxidative damage indicators (malondialdehyde (MDA) and electrolyte leakage (EL%)), which led to significant reductions in soybean relative water content (RWC), stomatal conductance, leaf K+, photosynthetic pigments, soluble protein. Subsequently reduced the vegetative growth (root length, nodules dry weight, and total leaves area) and seeds yield. However, there was an enhancement in the antioxidants defense system (enzymatic and non-enzymatic antioxidant). The individual application of PGPMs or Si-ZnNPs significantly improved leaf K+ content, photosynthetic pigments, RWC, stomatal conductance, total soluble sugars (TSS), CAT, POD, SOD, number of pods plant−1, and seed yield through decreasing the leaf Na+ content, MDA, and EL%. The combined application of PGPMs and Si-ZnNPs minimized the adverse impact of water stress and soil salinity by maximizing the root length, heavier nodules dry weight, leaves area, TSS and the activity of antioxidant enzymes, which resulted in higher soybean growth and productivity, which suggests their use under harsh growing conditions.

Effect of Soil Organic Ameliorants with Carbonized Rice Hull on the Growth and Yield of Shallot Onion (Allium ascalonicum L) on Salt Affected Soil

A pot experiment was conducted to test the potential of different soil organic ameliorants in salt affected soils reclamation; to test the effect of soil organic ameliorants on the growth and yield of shallot onion (Allium ascalonicum L.) planted in salt affected soil; determine the most effective soil organic ameliorants on salt affected soil Treatments prepared were; T1- Control Salt affected soil (1.57 kg/pot-1), T2- Vermi-cast (197.40 g/pot-1) with CRH (30 grams/pot-1),T3- Guano dung (39.40 g pot-1 with CRH (30 grams/pot-1), T4- Dried Goat Manure (115.40 g/pot-1) with CRH (30 grams/pot-1), T5- Dried Chicken Dung (94.94 g pot-1) with CRH (30 grams/pot-1), T6- Dried Cattle Manure (214.30 g/pot-1) with CRH (30 grams/pot-1). The study was laid out using Randomized complete block design with treatments and three replications. All organic ameliorants applied to the salt affected soil significantly improved on average bulb diameter, average height, average number of leaves, average bulb fresh weight, average number of tillers and average yield per hectare. It can be concluded that application of organic ameliorants is effective means to address the problem in saline affected soils.