Modeling Green Manure Additions in Alley-Cropping Systems: Linking Soil Community Dynamics and Nitrogen Mineralization

Abstract

The use of biomass in the form of litter, prunings, or roots as sources of nutrients for crops in alley-cropping systems has proven helpful in enhancing nitrogen availability for crops (Nair et al., 1997). Important considerations in managing alley-cropping systems are the amount and rate of N released that can benefit the crop in the alleys between the hedges. Understanding the short-term mineralization patterns of organic materials is a useful tool not only to assess but also to improve the suitability of hedgerow species (Isaac et al., 2000). Numerous studies in controlled and field conditions have successfully addressed the short-term decomposition and mineralization patterns of different species in relation to the initial chemical quality of the residues in order to make practical management suggestions. However, initial chemical quality of substrates alone is sometimes not sufficient to explain shortterm mineralization patterns. This is not surprising given the multiplicity of factors influencing decomposition and mineralization, including biochemical characteristics and soil biota composition and dynamics (Heal et al., 1997).