Effect of Phosphorus and Phosphorus-Solubilising Bacteria (PSB) on Alkaline Phosphatase Enzyme Activity in Soybean

Abstract

Soybean (Glycine max L. Merrill), a leguminous crop originating in Northern China, is primarily a pulse crop but has gained significance as an oilseed crop due to its 20% cholesterol-free oil content. This paper aims to evaluate the effect of phosphorus application and phosphorus-solubilising bacteria (PSB) on alkaline phosphatase enzyme activity in soybeans (Glycine max L.). A pot experiment was conducted during kharif, 2022, in the Net house of the Department of Soil Science & Agricultural Chemistry, College of Agriculture, Junagadh Agricultural University, Junagadh, to study the effect of Phosphorus and Phosphorus-Solubilising Bacteria (PSB) on soil phosphorus availability, yield and nutrient uptake by soybean. The experiment was laid out in a factorial completely randomised design with three replications having 16 treatment combinations viz. 4 levels of phosphorus (0, 40, 60, 80 kg ha-1) and 4 levels of phosphorus-solubilising bacteria (PSB) (0, 1, 2, 3 l ha-1). Results revealed that alkaline phosphatase enzyme activity at 30, 60 DAS and at harvest were significantly increased by the application of phosphorus up to 80 kg ha-1 and PSB 3 l ha-1. The combined application of phosphorus at 80 kg ha⁻¹ along with PSB at 3 L ha⁻¹ recorded significantly higher alkaline phosphatase activity at 30 and 60 DAS, as well as at harvest. The paper concludes that the maximum activity occurred under the combined treatment of 80 kg P₂O₅ ha⁻¹ with 3 L PSB ha⁻¹, demonstrating the synergistic role of phosphorus and PSB in enhancing soil enzyme activity and improving nutrient availability.