Possibilities for use of saline irrigation water for higher land productivity under groundnut – mustard rotation in salt affected Vertisols of Saurastra in Gujarat

A field experiment was conducted to assess the possibility for use of saline irrigation water in kharif groundnut (Arachis hypogeae L) and rabi mustard (Brassica junceae L) during 2005–06 and 2006–07 for higher land productivity of black clayey Vertisols. The experiment was conducted on fixed site. The soil was shallow, clayey, low to medium in fertility and calcareous in nature underlain by weathered or hard milliolithic limestone. The treatments using randomized block design with three replications were consisted of four salinity levels of irrigation water (0.5, 2, 4 and 6 dSm⁻¹ salinity). Five different cultivars of Spanish bunch group groundnut were grown in each plot. Results indicated that irrigation water of 2 and 4 dSm⁻¹ could be safely used as supplementary irrigation in groundnut depending on rainfall as well as native soil salinity and in mustard crop. The germination of groundnut was delayed by 3–4 days under saline water irrigation. The most vulnerable plant growth stages affected by water salinity were pod formation (No. of pods and pod weight per plant) in groundnut and initial plant growth stage like plant stand, plant height and days to flowering in mustard crop. The ‘rate of’ root zone salinity buildup was higher at lower water salinity level which was subsequently decreased with increased levels of salinity of irrigation water. It was clearly evident from the results that mustard crop was more resistant to salinity hazards as compare to groundnut crop.