Effect of P levels and foliar application of phosphate and phosphite on performance of soybean (Glycine max L.)

Abstract

A field experiment was conducted to evaluate the foliar application of phosphorus (as phosphate and phosphite) on the performance of soybean (Glycine max L.) during summer season of 2025 at College of Agriculture, Navile, KSNUAHS, Shivamogga. The experiment was laid out in RCBD comprising 11 treatments, replicated thrice. The treatments comprised of varying levels of P (75% and 100% of RDP) and combinations of potassium phosphate and potassium phosphite at 1% and 2% concentrations applied at 30 DAS. Among the different treatments, treatment T4 (100% RDP + 1% KH₂PO₄ foliar spray) recorded significantly higher plant height (47.33 cm), number of branches per plant (7.73), pods per plant (32.20), seeds per pod (2.86), seed yield of 23.04 q ha⁻¹ and stover yield of 30.76 q ha⁻¹. The crude protein (28.27), oil content (20.74) and phytate P (81.47) content of soybean seeds were also higher in treatment T4 (100% RDP + 1% KH₂PO₄ foliar spray).