Evapotranspiração e coeficientes de cultura do milho em monocultivo e em consórcio com a mucuna-cinza, usando lisímetros de pesagem

Abstract

The determination of the culture water demand throughout of its cycle and in different production systems improves the rational use of water. The objective of this work was to determine the crop evapotranspiration (ETc) and crop coefficients (kc) of corn under monoculture and intercropping system with gray-mucuna, using weighing lysimeters, installed in the center of the plots (144 m²). The kc values were determined by the ratio between ETc and the reference evapotranspiration (ETo). The ETo was estimated by the FAO Penman-Monteith model. The ETc values were calculated using the water balance of the lysimeter-corn-soil system, for the following stages of crop development: initial - Phase I (Emergence - 10% vegetative development “DV”); vegetative - Phase II (10% DV - 80% DV); production - phase III (80% DV - 100% DV “developed fruit”); maturation - Phase IV. The crop cycles and the total water requirement were 115 and 121 days, and 394 and 437mm, respectively, in the monoculture and intercropping system. The kc values for each phase of culture development in the intercropping system were: I (0.40 to 0.60), II (0.70 to 0.85) III (1.0 - 1 15) and IV (from 0.70 to 0.90). For the monoculture system, the kc values were: I (0.60 - 0.65), II (0.80 to 0.90), III (1.0 - 1.20) and IV (0.52-0.70). The kc values obtained for the intercropping system do not agree with the values proposed by FAO for the crop and for other consortium.