Benefícios ambiental e agrícola de um agrossistema indicado para a agricultura familiar do Maranhão

Abstract

The sustainable management of soils with low natural fertility used for family farming in the human tropics has been a great challenge, which, if overcome, would yield many advantages for the environment and for farmers. The objective of this study was to evaluate the environmental and agronomic benefits of alley cropping, by determining the amount of carbon captured, the indicators of soil quality, and the productivity for corn cultivation. Combinations of four legumes were used to make up the following treatments of plots: Butterfly pea + Pigeon pea (B+P); Acacia + Pigeon pea (A+P); Butterfly pea + Leucaena (B+L); Leucaena + Acacia (L+A); and Control. Corn was chosen because it is an economic crop. The carbon content in the various compartments of organic matter was determined, as was the mixed soil complex, the P content, the base saturation, the percentage of water saturation, the period during which the root hospitality factor fell below the critical level, and the productivity of the corn crop. It was concluded that alley cropping could serve as a substitute for slash and burn in the humid tropics. This would have environmental benefits, such as the maintenance of a dynamic equilibrium between entry and exit that could sustain up to 10 Mg ha-1 of carbon in the soil bed. From an agronomic point of view, the benefits of alley cropping are apparent in the increase in base saturation and the decrease in physical resistance to root penetration in the soil layer between 0 and 10 cm, which makes possible an increase in and the sustainability of productivity in corn cultivation.