Influence of precipitations on agricultural productivity in Paraíba State

Abstract

This study was carried out in four homogeneous pluviometric micro regions of Paraíba State between 1990 and 2005. The aims were to determine the relationships between crops of sugar-cane and pineapple productivity and production season rainfall in the Litoral and 'Brejo' micro regions, the relationships between the rainy season precipitations and herbecious cotton productivity in the Sertão, and sisal in the Cariri/Curimataú micro regions. Tests accomplished with polinomial regression equations, using only early rainy season or rainy season as the independent variable were not sufficient to estimate sugar-cane productivity in the Litoral, therefore small rainfall quantities do not supply the crop water contents. Pineapple productivity did not present significant correlations with rainfall in Litoral and 'Brejo' micro regions. Strong correlations were obtained between the rainy season precipitations and the herbecious cotton productivity in the 'Sertão', and with sisal in the Cariri/Curimataú. With the estimated precipitation values during the rainy season one could decide to plant, or not, in a particular micro region.