Evapotranspiração de cultura e influência de diferentes lâminas e freqüências de irrigação no crescimento e produtividade da cultura da cenoura.

Abstract

The evaluation of water requirement and of the crop coefficient is very important for an adequate irrigation management. However, there is a lack of information about carrot crop under northeast edaphic-climatic semi arid conditions, especially about crop carrot. The objective of this work was to evaluate the carrot crop evapotranspiration and crop coefficient (Kc) in alluvial area of semi arid of Pernambuco State, Brazil, where the communal agriculture is developed. Three drainage lysimeters were used, cropped with carrot, being the crop evapotranspiration (ETc) contability determined by mass balance in 5 days scale and the reference evapotranspiration (ETo) was estimated by Class A Pan methodology. The cumulative ETo during the experimental period was 615.02 mm, while the ETc was 811.84 mm. The coefficients band obtained, considering Kp values of 0.81 and 0.75 to the different growth stages were: 1.08-1.16; 1.41-1.52; 143-1.55 and 1.40-1.52, respectively, for the phases : beginning (20 days after plantation - DAP), growth (50 DAP), middle (80 DAP) and final (98 DAP), being the mean Kc of 1.35 and 1.46 for whole period. These values were higher than these presented by FAO and highlight the necessity of investigation of crop coefficient under local conditions.