Partial Replacement of Chemical N Fertilizer by Plant Compost Inoculated with Some Strains of Rhizobiain Barhee Date Palms Growing in Sandy Soil

Abstract

In sustainable agriculture, soil health and productivity depend on integrating bacterial inoculants with fertilizer management systems. Azotobacter-based biofertilizers are proposed as a substitute or supplement for artificial nitrogen fertilizers in crop production to enhance soil nutrient levels. In a laboratory experiment, around three rhizobial strains (two of Rhizobium leguminosarum127k80c and SU157" and one of Brady rhizobium japonicum USDA110spc4) were previously classified as plant growth-promoting rhizobacteria (PGPR). Barhee date palms were supplied with these microbial strains at 25 to 75 ml per palm and organic N (plant compost) fertilizers at 25 to 75% of the recommended amount as a partial replacement of chemical N fertilizer (ammonium nitrate) during 2022 and 2023 seasons. Providing Barhee date palms cultivated in sandy soil with nitrogen comprising 50 to 75% chemical nitrogen (ammonium nitrate) and 25 to 50% organic nitrogen (plant compost), along with any one of three nitrogen-fixing bacterial strains at 25 to 50 ml per palm, significantly enhanced growth characteristics, leaf pigments of nitrogen, phosphorus, and potassium, as well as flowering, fruit set, and yield per palm compared to the application of chemical nitrogen alone. The optimal bacterial strain was strain 1, succeeded by St-2, while St-3 ranked last. Enhancing Barhee date palm output. Fertilize trees with 50% commercial N fertilizer, 50% plant compost, and 50 ml/palm strain 1. 25% ammonium nitrate, 75% plant compost, and 75 ml St-3 gave the vines the best results.