Zoneamento agroclimático de culturas de subsistência em região semiárida

Abstract

In the Brazilian semi-arid region, the agriculture which prevails is the one of subsistence, composed of a rainfed cultivation system. There is great variability of rainfall in this region, both temporal and spatial, which damages agricultural crops. Thus, the need for good rural planning is essential, especially for the practice of subsistence, which aims at providing food security for the population. The main crops of subsistence which grow in this region are caupi beans/cowpea (Vigna Unguiculata (l.) Walp.) and corn (Zea mays). However, sweet sorghum (Sorghum bicolor L. (Moench)) emerges as a great agricultural potential for regions with semi-arid features. Thereby, the objective of this study was to elaborate and analyze the agroclimatic zoning for these main crops, in the region of the upper course of the Paraíba River Basin, which consists of the region with the lowest average rainfall in Brazil, using an unprecedented computerized methodology, that is based on the method of Thornthwaite and Mather (1955) and on the estimation, through equation, of the soil storage capacity (CAD). It was concluded that sorghum has better climatic aptitude for the studied area, reaching 81.23% of full aptitude, compared to 49.78% and 0.00% of beans and corn respectively. For the other classes, the result was 0.01% for beans and 0.0% for corn and sorghum in the moderate aptitude class due to excess water; 33.6% for beans, 0% for corn and 2.34% for sorghum in the full aptitude class, with little likelihood of excess water; 3.03% for beans, 83.48% for corn and 4% for sorghum in the moderate aptitude class due to water deficiency and; 15.52% for beans, 16.52% for corn and 12.41% for sorghum in the inapt aptitude class. All zoning process was carried out with a database of unprecedented content and more accurate than other similar works done in the same region.