Agronomic strategies for sustainable use of poor quality water in wheat (Triticum aestivum) and hybrid Bt cotton (Gossypium hirsutum) in a calcareous soil

Abstract

A field experiment was conducted from 2005–06 to 2008–09 on calcareous soil in semi-arid area, to evaluate the response of each furrow and alternate furrow irrigation in wheat [Triticum aestivum (L.) emend. Fiori & Paol.]– hybrid Bt cotton (Gossypium hirsutum L.) cropping system using irrigation waters of different qualities. Irrigation was applied to each and alternate furrow on bed-planted wheat followed by cotton for comparison with standard check-basin method of irrigation to both the crops. Three water qualities, namely good quality water (GW), saline-sodic water (SSW) and pre-sowing irrigation to each crop with GW and all subsequent irrigations with SSW (GWpsi+SSW), were evaluated under 3 methods of irrigation (check-basin, each furrow and alternate furrow). The pooled results over 3 years revealed that wheat grain yield was not affected significantly by the quality of irrigation water. However, significant wheat yield reduction was observed in alternate bed irrigation in all the water qualities. In hybrid Bt cotton, saline sodic water significantly reduced the seed-cotton yield in all the 3 methods of planting. The pre-sowing irrigation with GW and all subsequent irrigations with saline sodic water improved the seed-cotton yield as compared to the application of saline sodic water alone. However, in alternate furrow the yield increase was significant and the yield obtained was equal to the yield under alternate furrow in GW. Reduced use of irrigation water under alternate furrow resulted in 21, 21 and 25% higher water-use efficiency in wheat under GW, SSW and GWpsi+SSW respectively. The corresponding increase under Bt cotton was 28, 19 and 36%.