ASABE Technical Library - Abstract

Abstract. The high interannual variability of cotton production, in Barreiras (Bahia, Brazil), is strongly influenced by the impact in the variation in rainfall. Among the elements of climate, rainfall is what most affects agricultural productivity is the occurrence of dry spells. Probabilistic and standardized monitoring of temporal variability of rainfall totals, proposed by the model of Standardized Precipitation Index (SPI), have been used in the detection of severe rainfall deficits. The aim of this paper was to investigate the possibility of applying the concept of probabilistic and standardized monitoring proposed by SPI. The rainfall series using meteorological data from the weather automatic station of the National Institute of Meteorology (NIMET) located in Barreiras, Bahia, between 1990 and 2012, and the yield and the harvest cotton crop in the same period were used to evaluate the occurrence of droughts, demonstrated by the SPI and its relation to cotton productivity in the city. In order that, the data yields results obtained and the values generated by the standardized precipitation index (SPI), the correlations were around 0.78 among the cotton productivity in the city and the SPI.