Soil organic matter, nutrient cycling and biological dinitrogen-fixation in agroforestry systems

This special issue includes a series of manuscripts presented at the second World Congress of Agroforestry held in Nairobi, Kenya, 23–28 August 2009. The studies were performed in various tropical and temperate regions. They cover a wide range of topics on nutrient cycling in different agroforestry types: soil organic matter fractions, biological N2 fixation and soil enrichment. All of these case studies showed that soil organic matter fractions play an important role in soil C sequestration and nutrient cycling processes in agroforestry systems. Fallow systems enriched with leguminous trees appear to be a viable option for managing N despite the large amount of N removed from the system as timber and fuelwood.