Impact of inorganic fertilizer and microbial inoculation on nutrient content and uptake by soybean (Glycine max L. Merrill) in typic haplustepts
Abstract
A field experiment was conducted during the kharif season of 2025 at the Instructional Farm, Rajasthan College of Agriculture, Udaipur to evaluate the impact of inorganic fertilizer and microbial inoculation on nutrient content and uptake by soybean (Glycine max L. Merrill) grown on Typic Haplustepts. The study employed a two-factor factorial randomized complete block design with four levels in each factor and three replications. Factor A comprised inorganic fertilizer rates expressed as proportions of the recommended dose of fertilizer (RDF): F0 (control), F1 (50% RDF), F2 (75% RDF) and F3 (100% RDF). Factor B comprised microbial inoculation treatments: M0 (no inoculation), M1 (Rhizobium), M2 (Phosphate solubilizing bacteria, PSB) and M3 (Rhizobium + PSB). The results indicated that the highest nutrient content and uptake by soybean were recorded under 100% RDF (F₃), which was statistically at par with 75% RDF (F₂). Under F₃, the maximum nutrient content was 6.968 and 0.605% N, 0.605 and 0.220% P, and 1.353 and 2.63% K in seed and stover, respectively. Similarly, the highest total nutrient uptake was 113.72 kg N ha⁻¹, 17.00 kg P ha⁻¹, and 67.69 kg K ha⁻¹. Among microbial inoculation treatments, Rhizobium + PSB (M₃) recorded the highest nutrient content (6.934 and 0.594% N, 0.594 and 0.209% P, and 1.351 and 2.62% K in seed and stover, respectively) and total nutrient uptake (113.15 kg N ha⁻¹, 16.61 kg P ha⁻¹, and 67.76 kg K ha⁻¹), while Rhizobium and PSB alone were comparable to each other. Therefore, this study investigates the combined effects of inorganic fertilizers and microbial inoculation (Rhizobium and PSB) on the nutrient uptake and yield of soybean cultivated in the Typic Haplustepts of Rajasthan. This integrated approach offers a highly sustainable strategy to maximize soybean productivity, reduce chemical dependency and maintain soil fertility in semi-arid agricultural systems.