Crescimento e produção de mamoneira ‘BRS Gabriela’ submetida a níveis de irrigação.

Abstract

Castor bean (Ricinus communis L.) is considered a major source of raw material for biodiesel production, and in recent years has increased the demand for cultivated areas beyond traditionally exploited due to the policies of this oilseed production incentives arising the guidelines of the National program for Production and Use of Biodiesel. Therefore, it becomes necessary for the adoption of technologies to optimize production, which are appropriate to the specific conditions of each micro-region or locality. Among the major constraints in agricultural production in the semiarid region is the scarcity and irregular rainfall. While the castor bean is considered more tolerant to water stress, your productivity can be seriously affected by the amount of available soil water. Aiming to evaluate the agronomic performance of castor bean BRS Gabriela subjected to different irrigation, experimental testing was conducted at the Experimental Station of Embrapa Cotton, in the Barbalha city, Ceará. Experimental design used was randomized blocks, with distribution groups, with 4 replicates, totaling 24 plots. The treatments were distributed in 6 irrigation levels, applying 150, 125, 100, 75, 50 and 25% of crop evapotranspiration (ETc). The variables studied were plant height, stem diameter, number of racemes per plant, length of the primary raceme, height of insertion of the first raceme, number of fruits in the primary raceme, leaf area, 100-seed weight, oil content and yield. Data were subjected to analysis of variance and regression analysis. It was observed that: the growth of castor bean BRS Gabriela was increased when the plant was irrigated with water depth up to the limit of 77% of crop evapotranspiration (ETc), the yield reached its peak (859.18 kg of seeds per hectare) when plants were irrigated with levels 81% ETc; decreases in growth and productivity because of stress due to water deficiency in the soil, and the levels 100 levels 25% and 50% of Etc cause reductions in growth and yield of castor bean, and hipoxíticos anóxiticos due to stresses caused by excess water in the soil, the castor bean BRS Gabriela is very sensitive to excess water in the soil, with plant death when irrigated with levels up to 100% and so on.