Interferência da precipitação na produção de serrapilheira em área de caatinga submetida a diferentes manejos

Abstract

The Caatinga is the least studied and protected across all biomes and in recent years has been changing by human action biome. Studying the behavior of variables that allows the maintenance of natural biome is of great value, considering that the deposition of litter in forest environments is the main route of transfer in the flow of nutrients. The objective of this study assess Identify the relationships between rainfall and dry spells that occur in semiarid and litter production in time for the Caatinga biome, due to management applied to vegetation in semi-arid watersheds. The study was conducted in four watersheds located in the municipality of Iguatu, Ceará, Brazil. We collected monthly (from January 2008 to December 2012) the litter boxes placed in 20 1 m2 arranged in the vicinity of the main watersheds, travel. The collected material was placed in paper bags and taken to the Laboratory of Soil Science and Plant Tissue IFCE-Iguatu for the separation into fractions: leaves, branches, reproductive structures and miscellaneous; the dry mass of litter was obtained from a forced circulation oven at a temperature of 70 ° C until achieving constant weight, and then weighed in a precision of 0.01 g. RAL in the watershed management was applied thinning removing all trees with diameter greater than 10 cm leaving the plant remains in the area ; The watershed VN ( native vegetation ) had no treatment remained intact ; SBP ( Broca_Queima_Pastagem ) basin was removed all vegetation and subsequently held the burned watershed ENL , there was the cutting of vegetation leaving the remains enleirados in contour in the basin . The year with the highest total rainfall 2011 , had isolated rainfall events during the dry period in a total of 220 mm . These results show that both dry and rainy outliers are present always in upper ends and lower rainfall years in the high rainfall comprises isolated and disparate events. Regarding veranicos , the highest number of occurrences in the series for these studies was recorded in class 5 to 10 days ( event 246 ) , and if they are present throughout the rainy season. Throughout the study period there is a cyclic behavior of litter production , with maximum yields between the months of June and July and the minimum yield from November to December period. This fact expresses the strong relationship between the deciduous species that make up the savanna and the rainy season . It is observed that the watershed watershed RAL ( RAL ) was higher than 2008 although the total rainfall in 2009 was lower than in 2008 , the year (2009-2010 ) the leaf fraction contributed 80.14 % of total litter . Given the above it is concluded that : The management employees in the area changed the litter production ; the rainfall amount and duration of the rainy season influenced the litter production and independent production was seasonal nature of management applied.