Atributos químicos do solo em sistemas de derruba-e-queima e corte-e-tributação na Amazônia Oriental.

Abstract

he fires in the Amazon compromise soil fertility and are generally associated with known as slash and burn agriculture. The adoption of alternative techniques to the firing is very important to reduce the loss of organic matter and nutrients from the soil, resulting in increased agricultural crop production systems. The objective of this study was to evaluate the effect of two management systems, cutting and burning and cutting and grinding of secondary vegetation in the carbon content and chemical attributes Udult Northeast Pará. The study was conducted in a long-term experiment located at the Experimental Farm of Igarapé-açu (Feiga) of the Federal Rural University of Amazonia (UFRA), located in Igarape-Acu, Para Assessed management systems, both with nine years duration, were (a) cutting and grinding the remaining secondary vegetation of the fallow period and enriched with leguminous trees (cutting and grinding) and (b) cutting and burning of the remaining secondary vegetation of the fallow period (slash and burn); these systems were compared to secondary forest with more than 20 years (poultry). The experimental design was completely randomized in a 3x5 factorial design, the factors being: three treatments and five layers, with eight replications. Mean values of the chemical attributes decreased with increasing depth, except the content of exchangeable aluminum and aluminum saturation. The system of cutting and grinding higher concentrations of total carbon, available phosphorus, exchangeable calcium and magnesium, sum of bases, cation exchange capacity and effective potential and lower aluminum content compared with the system of slash and burn. Total soil carbon was strongly correlated with all soil chemical properties except pH H2O and pH KCl. The system of cutting and grinding has a higher content of nutrients and improved soil fertility in relation to the cutting and burning system.