Effect of method and level of irrigation on growth, yield and economics of spring-planted sugarcane (Saccharum officinarum)

Four methods of irrigations, i.e. irrigation in flat method, all furrows, alternate furrows and alternate furrows in rotation (odd and even furrow), and 3 levels of irrigation at irrigation water: cumulative pan-evaporation (IE:CPE) ratios of 0.6, 0.9 and 1.2 on sugarcane, were evaluated in 1997–98 to 1999–2000 with 3 replications. The cane yields of 61.5 and 61.0 tonnes/ha recorded respectively under irrigation in all furrows and in alternate furrows in rotation were at par and significantly superior to other 2 methods of irrigation. But the water-use efficiency of 65.67 kg/ha-mm and irrigation water saving of 33% were the highest when irrigation was given in alternate furrows in rotation (odd and even). The cane yields of 57.7 and 58.2 tonnes/ha recorded respectively under IW:CPE of 0.9 and 1.2 (16 and 19 irrigations). Similar trend was recorded in green fodder yield. Both methods and levels of irrigation influenced millable canes/ha but not the sugar content. The highest benefit: cost of 2.88 and 2.87 were obtained, respectively, under the irrigation methods of all furrows and alternate furrows in rotation. Irrigation at IW:CPE of 0.9 and 1.2 gave equal benefit: cost ratios which were substantially higher than 0.6 ratio.