| he trend toward shorter natural fallow periods in shifting agriculture emphasizes the need for management alternatives that accelerate nutrient accumulation and provide adequate weed control. Substitution of the natural fallows with cover crop-based managed fallows offers the potential to meet this challenge. The present study had the general aim of implementing a technology for reclaiming lands that shifting cultivators have recently abandoned in the Chapare region of Bolivia. The strategy was based on the use of tropical legumes (Canavalia ensiformis, Desmodium ovalifolium, and Pueraria phaseoloides) as managed fallows for 12 or 18 mo, followed by slashing and burning, or slashing only, the aboveground biomass at the end of the growth periods. Subsequent rotational crops (rice-cowpea-rice), along with changes in soil chemical properties, served to measure the efficiency of nutrient use. Additionally, the effect of commercial fertilizer on maintaining crop yields and soil productivity was evaluated. Cover crop dry matter accumulation followed the order Desmodium... |
