Evapotranspiration and Dual Crop Coefficient of Maize Second Season Intercropped with Crotalaria

Abstract

The objective of this work was to determine the dual coefficient of culture (Kc) of maize in monoculture and intercropping systems, as well as to evaluate the influence of intercropping on evapotranspiration and productive characteristics of maize second season. The experiment was carried out in the experimental field of the State University of Mato Grosso - UNEMAT in 2018, with three treatments: T1 - maize monoculture; T2 - Crotalaria monoculture and T3 - maize + Crotalaria. The crop evapotranspiration (ETc) of maize, Crotalaria, and maize + Crotalaria intercropping was determined daily by weight variation of weighing lysimeters, converted into mm day-1. The methodology used was that of dual Kc - FAO 56, dividing the crop coefficient (Kc), in soil evaporation coefficient (Ke), determined in microlysimeters, and basal crop coefficient (Kcb), determined in weighing lysimeters. The phenological phases of the maize crop were observed to determine the coefficients in the different developmental stages, being the Kc, Kcb, Ke in the phases: Initial (I), Development (II), Intermediate (III) and Final (IV). The accumulated culture evapotranspiration was 312.00; 436.16 and 422.38 mm and daily averages of 2.86; 4.00- and 3.88-mm d-1, respectively for monoculture maize, for Crotalaria and for intercropping. The Kc values for each phase of maize development in intercropping with crotalaria were: I (1.46); II (1.48); III (1.59) and IV (0.94). For maize monoculture, dual Kc values were: I (1.24), II (1.30), III (1.00) and IV (1.11) and for Crotalaria monoculture were: I (1.77), II (1.59), III (1.56) and IV (1.05).