Concentration and release patterns of nutrients (N, P and K) during decomposition of maize and wheat roots in a seasonally-dry tropical region

Abstract

Maize and wheat roots, enclosed in fine- (3 μ m) and coarse- (1 mm pore) mesh bags, were buried in soil in their respective post-harvest seasons. In all instances the N and P concentrations within the bags increased with time except for an initial decrease during the first few months. Concentrations of N and P were always higher in fine-mesh bags than in coarse-mesh bags. The nutrient concentrations in maize were higher in case of roots buried at 12.5 cm than at 5 cm depth. However, the absolute amount of N, P and K in the residual root mass decreased with time in all instances. Nutrient release rates were always greater in roots confined in coarse-mesh bags, suggesting a significant role for the soil fauna. The total release time for the various nutrients was about twice as long for wheat roots compared to maize roots.