Efeito do desmatamento da caatinga sobre as perdas de solo e água de um Luvissolo em Sumé (PB)

Abstract

Foram estudados os efeitos do desmatamento da caatinga sobre as perdas de solo e água provocadas por chuvas erosivas num Luvissolo. Os dados relativos aos anos de 1983-1990 foram obtidos na Estação Experimental de Sumé (PB), pertencente à Universidade Federal da Paraíba - UFPB. Os tratamentos consistiram de duas parcelas desmatadas, uma parcela com caatinga nativa, uma parcela com caatinga nova, duas macroparcelas com caatinga nativa e duas macroparcelas desmatadas. Nas parcelas desmatadas, as perdas de solo foram de 61,7 e 47,7 t ha-1 e as perdas de água de 224,2 e 241,0 mm. A parcela com caatinga nativa, quando comparada com a parcela desmatada, reduziu a perda de solo em cerca de 98% e a perda de água em torno de 73%. Nas macroparcelas desmatadas foram observadas perdas anuais de solo de 31 e 26 t ha-1 e de água de 151,3 e 131,5 mm. Nas macroparcelas com caatinga, houve uma redução de aproximadamente 99% das perdas de solo e 90% das perdas de água, em relação às macroparcelas desmatadas.The effects of native semiarid vegetation deforestation on soil and water losses caused by erosive rainfall in Haplargid were studied. The data covering the period of 1983-1990 were obtained from the Experimental Station of Sumé (Paraíba, from Brazil) of the Universidade Federal da Paraíba (UFPB). The treatments consisted of two deforested runoff plots, two runoff plots with native semiarid vegetation, two deforested watersheds and two watersheds with native semiarid vegetation. The deforested runoff plots, had soil losses of 61.7 and 47.7 t ha-1and water losses of 224.2 and 241.0 mm, respectively. When compared with the deforested runoff plots, the runoff plots with native semiarid vegetation reduced the soil losses in about 98% and the water losses in about 73%. The deforested macro runoff plots contributed with soil losses of 31.0 and 26.0 t ha-1 and water losses of 151.3 and 131.5 mm, respectively. In the macro runoff plots with native semiarid vegetation, there was a reduction of approximately 99% of soil losses and 90% of water losses, compared to the deforested macro runoff plots.