Cropping systems on permanent soil cover for Madagascar highlands

Introduction In Madagascar Highlands, population pressure and saturation of rice-cultivated lowlands speed up extension of cultivation on the fragile soils of the hillsides, with low fertility. Fertilisation being limited, yields remain low while erosion leads to paddy field silting-up and destruction of downstream infrastructures. To overcome these problems, experiments on direct planting on permanent soil cover (DPPSC) are conducted since 1991 in the farm of Andranomanelatra (Rakotondralambo and Razanamparany, 1998). In 1994, the research activities were enlarged to references sites, located in farmers’ field, which allowed to cover a large range of bio-physical and socio-economic situations.