Research activities undertaken by the soils/agroforestry unit of the FSRP (1985-1990)

In this heavily populated area, the use of long fallow periods to rejuvenate soil fertility does not seem to be a feasible option. Also, the landlocked location of Rwanda about 1,000 km from the nearest seaport makes importation and use of high doses of commercial inorganic fertilizers economically unattractive and logistically difficult for small farmers. Accordingly, agroforestry and organic matter- based cropping systems, using leguminous plants, are some of the promising intervention being evaluated in the research program. The specific studies reported here covered: (1) early growth of alley shrubs -- Sesbania, Leucaena, Calliandra, and Markhamia; (2) alley cropping Sesbania sesban (L) Merill with maize and beans; (3) choosing suitable intercrops prior to pruning sesbania hedgerows in an alley configuration; (4) herbaceous legumes as nutrient sources and cover crops; (5) green manuring with vetch on an acid soil; (6) application of two expert systems -- soil fertility capability classification (SFCC) and ACID -- for studying acid soils; and (7) agronomic evaluation of local lime material. The report also lists 23 research articles published by the program.