Water needs and equivalence relations for different irrigated crops in the São Francisco basin

Abstract

The present work was performed by applying the principal component analysis, in order to compare the
water needs of banana, mango, grape, sugarcane, maize and beans crops in different regions of the São Francisco river
basin, aiming to identify the climate elements that most influence the reference evapotranspiration (ET0
) in the locations
of Pirapora-MG, Jaíba-MG, Barreiras-BA and Petrolina-PE. In addition, the locations with more similarities, according
to the evaluated parameters, were verified by applying cluster analysis, and the equivalence relations between the
studied crops were determined by integrating the parameters related to the climatic elements and the characteristics of
crops and soils. Based on the principal components analysis, it was observed that the most significant climate elements
for ET0
estimation were different for each place. The model with two components explained 90%, 88%, 95% and 97% of
the total variance, respectively for the locations of Pirapora, Jaíba, Barreiras and Petrolina. Because it is in a semi-arid
climate region, Petrolina showed high crop water needs, a behavior proven with the cluster analysis. The equivalence relations
allowed comparing the water needs for the studied crops, providing, in general terms, a parameter comparison between the
crops, and specifying which one will be more adequate depending on the water availability in the São Francisco basin.