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This study aimed at evaluating whether 10 years of fallow was sufficient to restore a degraded hillslope in the semi-arid Caatinga biome, Brazil. For this purpose, runoff, erosion, loss of nutrients and organic carbon were measured on two comparable hillslopes: one was left fallow and the other degraded caused by overgrazing. Fallow management reduced runoff (36%), soil loss (65%) and organic carbon loss (81%) in comparison with the degraded hillslope. However, the fallow did not significantly reduce nutrient loss. Animal grazing has been shown to influence the nutrient cycle in the soil. The loss of organic carbon shows significant correlation with the loss of other nutrients, and may be used to estimate nutrient loss. Results show that a decade of fallow did not promote significant changes in the loss of nutrients, but was enough to reduce runoff, erosion and loss of organic carbon.

Resumo. O índice de área foliar (IAF) é um parâmetro biofísico que tem influência sobre vários processos ambientais, tais como fotossíntese, transpiração e balanço de radiação da superfície, sendo um importante parâmetro de entrada de modelos ecológicos. No bioma Caatinga ainda são escasso informações sobre o IAF e os fatores que o afetam direta e indiretamente seu valor. O estudo teve como objetivo avaliar a massa foliar específica (MFE) e o índice de área foliar para três tipos de associação solo-vegetação (ASV) em uma área de Caatinga preservada. O estudo foi realizado na Bacia Experimental de Aiuaba (BEA) por meio do método de coleta de serrapilheira. Duas unidades fitossociológicas em cada ASV foram levantadas para identificação das espécies e obtenção da massa foliar especifica. A MFE média das 17 espécies encontradas nas três ASVs foi de 56,6 g m Abstract. The leaf area index (LAI) is a biophysical parameter that influences various environmental processes such as photosynthesis, transpiration and surface radiation balance, being an important input parameter of ecological models. In Caatinga biome are still scarce information about the LAI and the factors that directly and indirectly affect its value. The study aimed to evaluate the specific leaf mass (SLM) and leaf area index for three kinds of soil-vegetation association (SVA) in a area preserved of Caatinga. The study was conducted at the Aiuaba Experimental Basin (AEB) through the litter traps method. Two phytosociological units in each ASV were raised to species identification and achievement of specific leaf mass. SLM average of the 22 species found in the three ASVs was 56.6 g m −2 . The results showed that the LAI in ASV3 (1.8 m 2 m −2 ) were lower than the ASV1 (2.7 m 2 m −2 ) mainly affected by soil type. The results of this research contribute to the understanding of the IAF's value in the Caatinga biome.

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