Indicadores físico, químico e biológicos de vertissolos no projeto de irrigação Várzeas de Souza e suas implicações econômicas, sociais e ambientais na região.

Abstract

The regional socioeconomic development is associated with a farming technified efficient for the increase and stability of food production, generation of employment and income. The implementation of irrigated perimeters becomes important to increase productivity, reduce the seasonality of food supply where lack of rainfall is a limiting factor. To boost irrigated agriculture in the semiarid Paraiba, especially fruit trees, was designed the Irrigation Project of Wetlands of Sousa (IPWS), replacing gradually areas of caatinga by different farming systems. This change in land use causes an imbalance in the ecosystem, which associated with the occurrence of Vertisols unwieldy, requires knowledge of its attributes as indicators of sustainable management techniques that ensure high productivity without compromising economic and environmental of the enterprise. The objective of this work was to identify the indicators physical, chemical and biological of Vertisols of the Irrigation Project Floodplains de Sousa, as well as their economic, social and environmental implications in the region. The experiment was carried out in IPWS in three batches cultivated intensively for four years, with conventional management systems (CMS), organic (OMS) and caatinga (CaMS). Soil samples were collected at 0-20, 20-40 and 40-60 cm for evaluation of the physical, chemical and biological attributes. Data were subjected to analysis of variance and mean comparison by test of Student-Newman-Keuls at 5%. Through the Landsat TM 5 did a temporal space analysis (1998 to 2011) for assessment of land use and vegetation of the caatinga. Questionnaires were applied to knowledge of the vulnerabilities agro-socioeconomics and environmental of the family farmers. The organic management system behaved near the CaMS, with better levels of soil physical properties in relation to CMS. The chemical attributes were little affected by land use for the three tillage systems. During the study period there was a decrease of the areas covered by dense vegetation and sparse scrub of 70.32% and 37.47%, respectively, and 54.73% of exposed soils with an expansion of the agricultural area of 303%. The vulnerabilities presented IPWS socioeconomic and environmental medium and high technological vulnerability with 33.12%, reflecting the lack of technical assistance and conservation practices. The quality of Vertisols can be kept for monitoring indicators of density, porosity, penetration resistance, organic matter content and cation exchange capacity.