Below-ground dynamics in agroforestry systems

A lot of progress has been made in root research during the last decade in tropical agroforestry that contributes to better understanding of the inter actions of roots and below-ground resource use in sequential and simultaneo us systems. New tools have been developed that allow in situ measurements o f root growth and interactions in woody and herbaceous species associations . There was much increase in information on root architecture, root behavio r and functions of potential tree and shrub species grown in associations w ith crops. Root behavior is influenced by genetic, site and management fact ors. The information can be utilized for minimizing competition for nutrien ts and moisture in agroforestry systems, especially under stress conditions , as often observed in dry zones or on acidic soils. Research is needed for more efficient utilization of below-ground growth resources by crops and/o r woody species to optimize returns in various agroforestry systems. Resear ch is also needed on the morphophysiological relationships of various root classes, on the contribution from root turn-over to soil organic matter and nutrient status, and on the need for indices for measuring root competitio n in agroforestry systems. Despite progress on knowledge of soil biota and faunal activities in agroforestry systems, research is needed to quantify t he effects on the sustainability of agroforestry systems.