Terras agrícolas e o processo de desertificação em municípios do semiárido paraibano.

Abstract

The study area includes the municipalities of Boa Vista, Cabaceiras, São João do Cariri, São Domingos do Cariri (Microrregião Homogênea dos Cariris Velhos) and Itaporanga (Microrregião Homogênea da Depressão do Alto Piranhas) State of Paraíba. In the Cariri the studied area totalizes 1,788.10 km2 approximately. The average altitude of the relief is of 450m and the rainfall average is of 400mm/y. The municipality of Itaporanga has an area of 467,10 km2 and the altitudes vary between 290m and 450m. The rainfall average is of 800 mm/y. The both areas are under the influence of hot and dry climate with rains in short periods and a extended dry season. The present work objectified to study the ENOS effect on the rainfall regimen, the water and farming production systems, the desertification process and the vulnerabilities of the rural families in municipalities of the semi-arid region of the State of Paraíba. The methodology was based on the use of TM/Landsat-5 and CCD/CBERS-2 orbital images obtained in different times of the year, bibliographical data, rural families’ vulnerabilities and field data. The results had indicated that for the period from 1987 to 2005 the vegetal covering in the municipalities of the Cariri was reduced and the land degradation levels had evolved for higher levels. For the municipality of Itaporanga, a small recovery of the vegetal covering had occurred and consequently had diminished the areas of occurrence of the most serious land degradation levels, however the levels most serious still occupy about 60% of the territory of the municipality. This situation is resulting of the high rural people vulnerabilities, whose indices had varied from high to very high - indices considered not acceptable. These vulnerabilities result from the lack of public polices for the agricultural sector and from a deficient water infrastructure, that increase the municipalities risks to the droughts, mainly in years of El Niño, period when the rural people intensify the use of the vegetal covering, resulting in the acceleration of the land degradation process, the reduction of the agriculture production in dry land and the migration of the rural population to urban areas increases.