Performance of four intercropping systems under variable monsoon onset condi- tions in rainfed semi-arid region of Rajasthan

Abstract

To provide a contingency cropping plan for the rainfed areas of hot semi-arid region of south-eastern Rajasthan a four seasons (2003 to 2007) kharif field experiment evaluated four intercropping systems viz. sorghum [ Sor- ghum bicolor (L.) Monech] + pigeon pea [ Cajanus cajan (L.) Millsp] (1:1), pigeon pea + black gram ( Vigna mungo L.) (1:2), castor ( Ricinus communis L.) + green gram [ Vigna radiata (L.) Wilczek] (1:2) and soybean [ Glycine max (L.) Merr.] + pigeon pea (4:1) under three dates of sowing, viz. first (normal) and third week of July, and first week of August. Four years mean pigeon pea grain equivalent data showed that sorghum + pigeon pea is the most re- munerative cropping system under normal monsoon conditions but the crop yields sharply decline with the de- layed onset of monsoon. The two week delayed planting of castor + green gram system did not show any yield re- duction while four weeks delayed planting reduced yield by 16% only as against corresponding yield reduction by 9 and 54%, 25 and 46% and 28 and 57% for sorghum + pigeon pea, pigeon pea + black gram and soybean + pi- geon pea intercropping systems respectively. Results indicated that if the monsoon onset is delayed by two weeks either castor + green gram or sorghum + pigeon pea should be the preferred cropping systems, whereas under four week delayed onset of monsoon situation only castor + green gram intercropping system has potential to maintain acceptable yield levels.