DECOMPOSITION OF SPECIES USED AS GREEN MANURE IN AN EXPERIMENTAL AGROFORESTRY SYSTEM, SANTARÉM, PARÁ

Abstract

Agroforestry systems are consortia that have food and timber crops in their arrangements, and their sustainability is established as a function of the interactions of the decomposition flow of the existing species. In this sense, green manuring is the new practice used to promote nutrient cycling in production systems, with legumes being the most suitable species to compose this type of fertilization. The objective of this work was to evaluate the leaf decomposition rate of the bean (Canavalia ensiformis (L.) DC.), gliricidia (Gliricidia sepium (Jacq.) Walp.), pigeon pea (Cajanus cajan L.) and leucaena (Leucaena leucocephala (Lam.) de Wit.) used as green fertilizer in an agroforestry system (SAF) using the litter bags method. The study was carried out in the experimental SAF, Federal University of the West of Pará (UFOPA) from april to september 2017. The leaf fraction was analyzed for 5 times periods, with collections at 30, 60, 90, 120 and 150 days. The data were adjusted by means of a nonlinear equation to obtain the decomposition constant (k) and the calculation of the half-life time, being analyzed statistically by the Tukey test at 5% probability. The gliricid. Presented a higher decomposition rate in relation to the other species evaluated, but the guandu, although it obtained a slower rate, could help to maintain the cover and soil moisture. The decomposition of all species was more pronounced during the first 90 days of the experiment.KEYWORDS: Biomass, Leaf decomposition, Leguminous.