Effect of Phosphorus and Zinc Nutrition on Yield, Nutrient Uptake and Soil Fertility in Fodder Cowpea (Vigna unguiculata L.)

Abstract

Background: Productivity of fodder cowpea (Vigna unguiculata L.) in sandy loam soils is often constrained by inadequate phosphorus and zinc availability. Balanced fertilization is essential to enhance nutrient uptake, fodder yield and soil fertility. Methods: In Andhra Pradesh’s Southern Agro-Climatic Zone, a field experiment was carried out during the rabi season. The effects of zinc (0, 25 and 50 kg ZnSO4 ha-1 as factor-II) and phosphorus (0, 20, 40 and 60 kg P2O5 ha-1 as factor-I) on nutrient uptake, post-harvest soil nutrient status and cowpea fodder output were investigated using a factorial randomised block design. Result: Application of 60 kg P2O5 ha-1 significantly increased nutrient uptake and produced the higher green and dry fodder yields. Zinc application at 50 kg ZnSO4 ha-1 significantly enhanced fodder yield and nutrient uptake and was at par with 25 kg ZnSO4 ha-1. Higher nutrient levels reduced residual soil nitrogen and potassium due to increased uptake, while soil phosphorus and zinc status improved. Interaction effects were non-significant. Combined application of 60 kg P2O5 ha-1 with 25 kg ZnSO4 ha-1 was found optimal for fodder cowpea.