Enhancing Soybean Quality, Nutrient Content and Uptake through Combined Soil and Foliar Nutrient Application under Vertisols

Abstract

This field experiment evaluated combined soil and foliar nutrient application for improving soybean quality, nutrient content and uptake under Vertisol conditions during the kharif season of 2022 at the Instructional Farm, College of Agriculture, Ummedganj-Kota, Rajasthan. The experiment used a randomized block design with three replications and ten treatments involving the recommended dose of fertiliser (RDF) and foliar applications of urea, DAP, NPK (18:18:18), Fe and Zn at 35 and 60 DAS. The treatment comprising RDF + 2% NPK (18:18:18) + 0.5% Fe + 0.5% Zn at 35 and 60 DAS produced the highest protein content (40.56%), protein yield (725.5 kg ha⁻¹), oil content (20.27%) and oil yield (362.6 kg ha⁻¹). It also recorded the highest N, P and K contents in seed and straw, together with the highest Fe and Zn contents. The same treatment recorded the maximum total uptake of N, P, K and S (181.3, 12.30, 108.5 and 15.8 kg ha⁻¹, respectively) and Fe, Zn, Mn and Cu (349.5, 82.5, 237.7 and 47.3 g ha⁻¹, respectively). Sulphur content and manganese and copper contents were not significantly influenced by the nutrient treatments. Under the conditions of this single-season experiment, supplementing RDF with foliar NPK, Fe and Zn improved soybean quality and nutrient acquisition relative to the tested treatments.