Risk climatic zonation for the cowpea crop in Ceará State, Brazil.

Abstract

A water balance model was used for estimating the climatic risks using water deficit for cowpea crop, when cultivated in different soil water retention capacity (sandy, loam and clays soils), from November to May, in Ceará State, Brazil. The areas with low, medium and high climatic risk were zoning by a geographic information system. Cowpea crop has different climatic risks in function of growing season and soil type. For all soil water retention capacity, the planting date from 20th to 31st January was the most favorable for the cowpea development at the central and south counties of the Ceará State. For the counties of the north of the Ceará State, the planting date must be from 1st to 10th March, because the rainy season occurs from April to May with additional advantage of harvest be processed when the dry season is beginning.