Four experiments were conducted from August 2007 to November 2009—one greenhouse experiment, one lysimeter study, and two field experiments—to study the relationship among growth, yield, morphology, and water use efficiency of sugarcane under different water regimes at the Sugarcane Research and Seed Farm in Pyinmana, Mandalay Division, Myanmar.
In the barrel experiment, canes grown in 15- and 40-cm water tables depth had higher shoot and root dry weights than the control with no sub-irrigation. Sugarcane grew taller in barrel with compartment and was not affected by interplant varietal competition. PMA 96/56 had a high growth rate due to rapid root dry mass production, root length, and had higher resistance to drought than K 84/200.
The total sugarcane water consumption in the lysimeter study was 1,369.84 mm yr-1 and the average sugarcane yield was 173.29 t ha-1. Water use efficiency in the lysimeter study was 12.65 t cane ML-1 (0.13 t mm-1). The locally determined Kc values were 0.53, 0.81, 1.25, and 1.27 for initial, development, mid, and late sugarcane growth stages, respectively.
In the irrigation trial conducted in 2008, the amount, time, and frequency of irrigation used were 80 mm for canes irrigated once in March and April, and 160 mm for canes irrigated twice (once each in March and April). Irrigated canes (PMA 96/56, Phil 74/64, and K 84/200) produced higher root dry mass, and cane and sugar yields than rainfed canes. When irrigation water was limited in March or April, K 84/200 had the highest water productivity, while PMA 96/56 had lowest.
In the irrigation trial conducted in 2009, the amount, time, and frequency of irrigation used were 30 mm for canes irrigated once in February, 80 mm for canes irrigated once in March, 70 mm for canes irrigated once in April, and 180 mm for canes irrigated thrice (once each in February, March, and April), applied during the early cane establishment stage. Responses to irrigation and rainfed condition in root and leaf parameters varied considerably among varieties. Irrigated canes (PMA 96/56, Phil 74/64, and K 84/200) produced higher cane and sugar yields than rainfed canes. Sugarcane irrigated once in February gave the highest WUE for PMA 96/56. In areas where water resources are limited and/or are solely relying on rainfall for production, sugarcane should be irrigated at least once during the active tillering stage (60-70 DAP) for better cane and sugar yield.