Climatic regionalization and rainfed agricultural production in the state of Maranhão, Brazil

Abstract

This study had as specific objectives: a) To evaluate whether the climatic regions created for the state present differences in their respective rainfall and air temperature averages, considering the series of rainfall and temperature precipitations observed between the years 1901 to 2020 and b) To evaluate the instability of rainfall and annual air temperatures in Maranhão between the years 1901 to 2020 with unfolding for the 10 climatic sub-regions into which the state was divided; c) to show the aggregate behavior of rainfed crops in these different regions. The data used were collected from NOAA (2022) and IBGE's Municipal Agricultural Surveys (PAM) in several years. Dummy variables were used to test whether the ten climatic regions had different averages of both rainfall distribution and annual temperatures. To assess the adequacy of rice, bean, cassava and maize crop yields to the regions created, the factor analysis method was used to generate weights in which harvested areas, yields, prices and rainfall were aggregated at the level of the 217 municipalities of the state of Maranhão. The results showed that Maranhão has ten regions with rainfall regimes whose annual averages are different. They also showed that the same does not apply to average annual temperatures, which were more homogeneous. As for aggregate agricultural production, it was observed that in five of the ten regions, crop yields show different behavior from the others.