Consumo hídrico da cultura do gergelim na região da chapada do Apodi -RN.

Abstract

The field experiment was conducted at the Experimental Agricultural Research Farm Company of Rio Grande do Norte (RN) – EMPARN, located in Apodi, RN.The study period was from August 11 to October 31 of 2015 whose objective was to study the water consumption of the gergelim's crops (Sesamum indicum L) to soil and climatic conditions of the semiarid region of Apodi - RN. For the study, it was used the methods of water balance in the soil to estimate the crop evapotranspiration (ETc), Penman's method - Monteith to estimate the reference evapotranspiration (ETo) and the relationship ETc/ ETo to determine the crop's coefficient (Kc). In the experiment we studied the gergelim BRS ANAHI crop. The Irrigation was carried out by nozzles distributed throughout the experimental plots and was applied to the entire cycle equivalent to 534.9 mm of water. The gergelim's cycle was 82 days, distributed in phase I, the plants germination period was up to 10% coverage, with duration a of 13 days; Phase II, 10% of the coverage to the beginning of flowering, which lasts 22 days; Phase III, the beginning of flowering to early fruit maturation, lasting 33 days; and phase IV - Final stage of ripeness of the fruit to harvest, lasting 14 days. The total water consumption was 502.2 mm throughout the cycle and the average for each phenological stage was 43.8 mm (Fase I), 121,7 mm (Fase II), 268,5 mm (Fase III) and 68,2 mm (Fase IV). The cultivation coefficient (Kc) showed an avarage value for each phenological stage 0.51; 0.73; 1.03 and 0.59 for the phases I, II, III and IV, respectively.