Low-input cropping for Acid soils of the humid tropics.

A low-input cropping system has been developed at Yurimaguas, Peru, to serve as a transition technology between shifting and continuous cultivation for acid soils of the humid tropics. Principal features are slash-and-burn clearing, rotation of acid-tolerant upland rice and cowpea cultivars, maximum residue return, no tillage, and no lime or fertilizer applications. When yields decline as a result of increasing weed pressure and nutrient deficiencies, a kudzu fallow is grown for 1 year. Subsequent options include fertilizer-based continuous cultivation, pastures, or agroforestry. The system preserves some agroecosystem diversity and contributes toward a sustainable level of production and income for farmers in humid tropical regions.