Nutrient Management in Castor (Ricinus communis L.) and Castor-based Cropping Systems

摘要

Castor is an important non-edible industrial oilseed crop having profound commercial significance in terms of export earnings.The nutrient requirement of the sole crop vis-a-vis that under cropping systems and under irrigated conditions differ from that raised under rainfed conditions and from soil to soil.A castor crop yielding 10 q/ha under rainfed conditions removes 40 kg N,9 kg P_2O_5 and 16kg K/ha as against 84 kg N,26 kg P and 31 kg K/ha removed by a crop of 22.8 q/ha under irrigated conditions.Variable response of sole castor to applied nutrients have been obtained depending upon the soil type,moisture supply,fixation capacity of soil etc.Differential response of castor genotypes to fertiliser has also been noted.Under rainfed situations deep ploughing has a synergistic effect on fertiliser response.Under irrigated conditions the crop response to applied nitrogen in splits was greater.Although the response to applied phosphorus has not been greater owing to better use of native phosphorus by the deep root system,application of single superphosphate as source of phosphorus can confer beneficial effects.Under irrigated conditions application of gypsum was found beneficial.Based on the research carried out under different crop growing situations,recommendations have been made for integrated nutrient supply system in castor.Nutrient management for production of foundation seed of pistillate lines and for certified hybrid seed production has been appraised.Besides,fertiliser management in castor based sequential as well as intercropping systems both under rainfed and irrigated situations have been reviewed.