Saline Water Irrigation Through Drip for Groundnut-Wheat Cropping Sequence In Hyper Arid Region of Rajasthan

Abstract

A field experimentwas conducted to assess the suitability of saline water for irrigation,and to know theirrigation water requirement of groundnut-wheat cropping sequence in hyper-arid region of Rajasthan. In this split-plot experiment, the main plots had four levels of irrigation water salinity (ECiw0.25(Best available water, BAW), 4, 8 and 12dS.m-1); and the sub-plots had combinations of two treatments on drip lateral spacing of 0.60 m and 0.90 mwith 0.30 m emitter spacing,and three levels of irrigation water application(0.6, 0.8 and 1.0 times of pan evaporation (PE)).The highest biological yield (grain + straw) of wheat and groundnut recorded in BAWwas statistically at par with irrigation water salinity level of4 dS.m-1. Higher irrigation water salinity levels (8 and 12dS.m-1)and placement of laterals at 0.90 m led to significant reduction in biologicalyield. In monetary terms, use of BAW resulted in highest B:C ratio of 1.73 for groundnut-wheat cropping sequence, while ECiw 4 dS.m-1showedB:C ratio of 1.70. The hHighestcrop yields,gross return and B:C ratio were observed under 0.60 m lateral spacing and irrigation application at 1.0 PE.Interaction effect of salinity of irrigation water and lateral spacing on yield and yield attributes was significant for both crops.Study demonstrated that the salinity limit of 4 dS.m-1 can be considered as threshold irrigation water salinity for drip irrigated groundnut and wheat crops in hyper-arid region of Rajasthan.