Avaliação de crescimento e hídrica da cultura da pinha em Rio Largo, Alagaoas.

Abstract

The pine crop is of great interest to many farmers in the state due to the good prices achieved in the market, the possibility of production at different times of the year and the possibility of producing two annual crops when managed and under irrigation. There are few studies, related to soil water content and evapotranspiration of this crop, especially in the state of Alagoas. Therefore, a field survey was carried out between April and 2016 and January 2017, with the objective of analyzing growth variables and water conditions in the crop. The orchard was installed in an area of 1008 m², spacing between plants of 3.0 x 3.0 m with a total of 112 plants that use the area of creole. Evaluating the following: plant height, leaf area index, canopy diameter, accumulated degrees-day, reference evapotranspiration (ETo) methods, crop coefficient (Kc) and water balance. Statistical analysis was performed using the statistical indices: correlation coefficient (r), Willmott concordance index (d) and root mean square error (RMSE). The estimation of ETo by the different methods presented an average ETo of 5.00 mm day-1 for the standard method ETo 1, 5.74; 5.38; 6.45 and 5.86 respectively for the other methods, ETo 2, ETo 3, ETo 4 and ETo 5. As well as a maximum plant height of 1.02 m, maximum LAI of 0.52, maximum canopy diameter of 0.35 m and an average Kc of 1.13 by the standard ETo estimation method. The established water balance was that of Thornthwaite and Mather, 1955 in which, it presented an average obervado storage of 16,42 mm and the estimated by the TDR of 17,42 mm.