Rainfed crops forecasting in the semi-arid region under scenarios of rainfall instability in Ceará, Brazil

Abstract

This paper aimed to analyze the projections of rainfed crops (rice, beans, cassava and corn) in the semi-arid region under scenarios of rainfall instability in Ceará, in the period from 1945 to 2020. The data were collected from the Meteorology and Water Resources Foundation of Ceará (FUNCEME) and the Brazilian Institute of Geography and Statistics (IBGE), through the IBGE System of Automatic Recovery (SIDRA), which provides data on Municipal Agricultural Production (PAM-2020). The rainfall periods were organized in three categories: drought, normal and rainy periods. This was done using the historical average and standard deviation of rainfall from 1945 to 2020. The projections of production variables were made through the Autoregressive Integrated Moving Average (ARIMA) methodology. The results show that the rainfall distribution in Ceará State between 1945 and 2020 was quite unstable. The coefficient of variation (CV) of the rainfall periods ranges between 33% in normal period and 54% in the drought period. Based on the results, it is observed that the general hypothesis of the article was confirmed, showing that rains have an impact on rainfed agricultural production in Ceará in the variables: harvested area, productivity and prices of rice, beans, corn and cassava crops. The results also showed that the cassava crop presents favorable results in relation to the interference of rainfall, suggesting that the crop is better adapted to the climatic adversities of the region.