Aptidão climática para os cultivos agrícolas da Mandioca (Manihot esculenta C.) e do Sorgo (Sorghum bicolor L. Moench) no estado do Maranhão

Abstract

When we make a climatic aptitude survey of the main cultures from a specific location, it will be possible to reach a better optimization on agricultural harvests, bearing in mind that climatic anomalies are the main causers of decreases on the mundial agricultural productivity. The manioc is one of the main subsistence cultures cultivated on Maranhão, being a crucial product to the decrease of the alimentar insecurity in the state. The Sorghum, besides adapting very well on the nordestin region, and being resistant to drought, the occurrence of hydric deficits, mainly on the bloom phase and on grain fillings, may cause accentuated reduction on production. With the exposed one, this work had like objective to evaluate the agroclimatic potential from the Maranhão state to the cultivation of Manioc and Sorghum. The research was developed for the 10 homogeneous regions from Maranhão. The description of the climatic demands for the analyzed cultures was realized from the air temperature datas and pluvial precipitation. To the calculation of the hydric balance was utilized the proposed method by Thornthwaite and Mather. The aptitude climatic criterions of the manioc were the humidity index (Ui), hydric (Hi) and aridity (Ai). The climatic aptitude evaluation for the Sorghum culture, was given by planting times. Analyzing the datas, it has been seen that it did not had thermal restrictions for both cultures, in relation to 10 analyzed homogeneous regions. To the manioc cultivation, the region R1 has been the most rainy, being classified with moderated aptitude, because of the hydric excess. The regions R2 to R8, that cover good part of the state, showed full aptitude, but with risks of showing prolonged rainy period. The regions R9 and R10 showed a negative predominant hydric index, being classified with full aptitude for the manioc cultivation. In relation with the sorghum cultivation, they showed climatic inaptitude by hydric deficiency, the planting beginning on the months: June (R1, R2, R3, R4, R5 and R6), May (R2, R3, R4, R5 and R6), April (R5, R6, R7, R8 and R9), March (R10), November (R7 and R8) and October (R10); showed restricted aptitude by excess or hydric deficiency, the beginning of the plantation on the months of May (R1), April (R1, R2, R3 and R4), March (R1 until R9), February (R1 until R8), January (R1 until R8), December (R7, R8, R9 and R10) and November (R9 and R10) and; showed full aptitude, the beginning of the plantation on the months of January and February (R9 and R10). Concluding, none of the 10 analyzed regions showed inaptitude to the manioc cultivation on Maranhao. The regions R9 and R10, located on the south of the state, were the only ones who showed full aptitude for both cultures. The climatic aptitude classification for the sorghum culture is far more specific and careful than the manioc