Influence of potassium fertigation on productivity of castor beans

One of the viable alternatives to the occupation of the space left by the cotton in semi-arid region of Ceará is the cultivation of castor beans, for the production of biodiesel. However, the studies already conducted with the culture did not provide information about the application of nutrients through irrigation water. Given the above was carried out in Fortaleza (03 ° 44'S, 38 ° 33'W, 19.5 m) an experiment to evaluate the effect of different doses of potassium applied by fertigation in the production of castor beans. During the crop cycle, the plants were drip irrigated daily, where the irrigation accounted for 75% of pan evaporation in the tank class "A" (ECA). The experimental design was randomized blocks with five treatments and four replicates, depending on the potassium fertigation: 0, 50, 100, 150 and 200 % of the recommendation of soil analysis. The use by producing larger amounts of potassium by fertigation increases to a certain threshold weight of 100 seeds of the racemes of 2nd and 3rd order and the yield of the racemes of 2nd and 3rd order and total, from which these variables are decreasing.