Decomposition and nutrient release pattern of three potential leguminous green manure crops of Mizoram

Abstract

Aim: The experiment was carried out to understand the decomposition and nutrient release dynamics (N, P and K) of Crotolaria micans Link, Aeschynomene indica L. and Calopogonium mucunoides Desv. using the litter bag technique. Methodology: The species were harvested at their peak vegetative stage and air-dried for a week. Air-dried samples (10 g) were placed in 20 cm X 20 cm nylon mesh bags and buried at 10 cm soil depth in an experimental plot of 1.5 m X 1.5 m prepared for each species. The bags were retrieved monthly, and the mass and nutrient loss were determined. Results: C. micans had the highest decay rate (7.67 k per year), followed by C. mucunoides (7.15 k per year) and A. indica (5.50 k per year). During the decomposition period, K release was the fastest. The decay rate was negatively correlated with initial lignin, total phenol and lignin/N of which the total phenol (R2 = 0.956) and lignin/N ratio (R2 = 0.832) had the most significant influence on decomposition. Interpretation: The study reveals that the species can be effectively utilized as a soil nutrient input source of which C. micans seems to be the most potential species to be further researched and developed as a green manuring crop. Key words: Decomposition, Decay rate, Green manure, Legume, Nutrient release