A 4-year field experiment was conducted in a semi-arid area to evaluate the response of each furrow and alternate furrow irrigation in wheat-cotton system using irrigation waters of different qualities in a calcareous soil. Irrigation was applied to each and alternate furrow of bed-planted wheat followed by ridge-planted cotton for comparison with standard check-basin method of irrigation to both the crops. These methods of irrigation were evaluated under three water qualities namely good quality canal water (CW), poor quality tube well water (TW) and pre-sowing irrigation to each crop with CW and all subsequent irrigations with TW (CWpsi+TW). The pooled results over 4 years revealed that wheat grain yield was not affected significantly with quality of irrigation water, but significant yield reduction was observed in alternate bed irrigation under canal water and tube well water irrigations. In cotton, poor quality tube well water significantly reduced the seed cotton yield in all the three methods of planting. The pre-sowing irrigation with canal water and all subsequent irrigations with tube well water improved the seed cotton yield when compared with tube well water alone. However, this yield increase was significant only in alternate furrow irrigation, and the yield obtained was on a par with yield under alternate furrow in CW. When compared to check-basin irrigation, each furrow and alternate furrow irrigation resulted in a saving of 30 and 49% of irrigation water in bed-planted wheat, whereas the corresponding savings in ridge-planted cotton were 20 and 42%, respectively. Reduced use of irrigation water under alternate furrow, without any significant reduction in yield, resulted in 28.1, 23.9 and 43.2% higher water use efficiency in wheat under CW, TW and CWpsi+TW, respectively. The corresponding increase under cotton was 8.2, 2.1 and 19.5%. The implementation of alternate furrow irrigation improved the water use efficiency without any loss in yield, thus reduced use of irrigation water especially under poor quality irrigation water with pre-sowing irrigation with canal water reduced the deteriorating effects on yield and soil under these calcareous soils.
