Evapotranspiração real na fase inicial de crescimento da laranja lima

Abstract

Determine the actual evapotranspiration (ETr) is an important factor for the management of irrigation, in order to meet the need of agricultural crops. The objective of this research was to analyze the accuracy of a model to estimate actual evapotranspiration in the metropolitan area of Maceió, in addition to analyzing the initial growth phase of orange file and get the crop coefficient. The experiment was carried out between April 2016 and March 2017, and the trial period of the corresponding search to eight months (August 2016 to March 2017). The same was conducted in an orchard in the experimental area of Agricultural Sciences Center of the Federal University of Alagoas. Orchard area possessed dimensions of 68 meters long by 28 meters wide, totaling 1,904 m2, with 7 lines of cultivation, with 16 plants each, in a spaced 4.0 x 4.0 m, thus totaling a population of 112 plants in the area where it was evaluated 4 plants per row crops. It was found during the search of total cumulative rainfall of 850 mm, and a total accumulated ETo and average of 1555 mm and 4.43 mm day-1, respectively, an average temperature of 25.36 °C and humidity on average 71.08% of air. We evaluated the following parameters during the search leaf area index, canopy diameter, plant height, degree-days, water balance, cropping coefficient (Kc) and evapotranspiration six adjustment coefficients (Ca), 0, 05, 0.1, 0.2, 0.3, 0.4 and 0.5. The data from soil moisture were obtained with the aid of sensors, by time domain reflectometry (TDR). Statistical analysis was performed using the statistical indices: correlation coefficient (r) Willmott agreement index (d) and root mean square error (RMSE). On this basis, concerning the morphology of plants, maximum leaf area index shown in culture was 0.79, the diameter of the canopy equivalent to 52.31 cm, the plants reached a maximum height of 0.93 m. We obtained a Kc of 0.84 for the initial stage of file orange growth. ETR estimated using a coefficient of 0.05 by Poulovassilis method showed higher agreement with ETR obtained in the field where average amounts were 4.20 mm and 4.83 day-1, respectively.