Taxa de decomposição de serrapilheira em fragmento de caatinga e sistema de produção agroecológica no Município de Ipanguaçu-RN

Abstract

Nutrient cycling in forest ecosystems, whether cultivated or spontaneous, has been widely studied, with emphasis on the litter layer, which prevents direct exposure of the soil, protecting the microorganisms that are present and maintaining adequate waterproofing, preventing erosion. This importance of litter for the formation of organic matter in the soil is crucial to maintaining balance in the environment. Therefore, the objective of this experiment was to evaluate the decomposition rate of two distinct areas (agroforest and legal reserve of the school farm), in addition to correlating it with climatic factors in the region (Semi-arid region of the State of Rio Grande do Norte). Leaves that had recently fallen to the ground were collected randomly, in the two areas used in the experiment, where they were transported to the soil laboratory, and placed in the forced air oven for 72 hours at a constant temperature of 65 0C and subsequently the leaves were removed from the forced air circulation oven and weighed on a 0.0001 g precision scale, to obtain the initial weight of 10.5 grams for all treatments, in the 40 litter bags used in the experiment. In each experimental area, 20 litter bags were placed, which were properly labeled and distributed on the surface of the soil, in an area of 225 (m²) at UTD Agrofloresta and in an area of 4,489 (m²) in the fragmented part of the legal reserve. After periods of 30, 60, 90,120 days, 5 litter bags were removed from each sector, for each treatment. After removal from the field, the litter bags were transported to the soil laboratory, with the leaves from each of the replications being removed into cardboard bags that had all the identifications for each plot. Then, the bags were placed in the forced air circulation oven for 72 hours at a constant temperature of 65 0C and subsequently the leaves were removed to weigh and carry out statistical analysis of the experiment. The data were subjected to a normality analysis, using the Shapiro-Wilk test; then an Analysis of Variance (ANOVA) was carried out to test the significance of the differences between the means of decomposition rates between the different treatments and an Analysis of Covariance (ANCOVA). Among the covariates tested, Temperature was the only variable that presented statistical significance (p-value = 0.0370), indicating a relevant effect on the decomposition rate.