Evaluation of Soil Test Methods for Determination of Available Nitrogen, Phosphorus and Potassium under Mungbean in Mollisols

Abstract

The present study focussed on evaluating combinations of soil test methods for estimating available nitrogen (N), phosphorus (P) and potassium (K) under mungbean (Vigna radiata L.) grown in Mollisols of Uttarakhand. Composite soil samples (0-0.15 m) were collected before sowing of mungbean and application of fertilizers and farmyard manure (FYM). Indices for soil available N were used as organic carbon (OC) and alkaline KMnO4-N, for available P Olsen’s-P and ABDTPA-P and for available K neutral normal NH4OAc-K and ABDTPA-K. Multiple linear regression analysis was performed and suitability of soil test methods combinations for given soil nutrients was compared using R2 values. Results indicated that R2 values of different combinations of soil test methods were highly significant (p<0.01) in mungbean. Highest R2 values obtained were 0.696**, 0.694**, 0.680**, 0.634** and 0.723** for combinations of alkaline KMnO4-N, ABDTPA-P, ABDTPA-K with grain yield, total N uptake, total P uptake, total K uptake and protein yield as dependent variables, respectively. It suggests that alkaline KMnO4 for available N along with multinutrient extractant for available P and K can be taken as reliable combination of soil test methods for prediction of soil test values for available N, P and K for mungbean under Mollisols.