DEVELOPMENT OF A METHOD TO IMPOSE WATERLOGGING ON SUGARCANE GROWN IN POTS

RECENT PRODUCTIVITY REVIEWS in the Herbert and Central regions identified strong negative correlations between excessive rainfall and productivity. Waterlogging has been estimated to reduce yield by 0.5 t/ha for every day the water-table is within 50 cm of the soil surface. Identification of varieties that perform better under waterlogged conditions is based on anecdotal observations from the field, after a variety is released. If a variety’s tolerance was known closer to the time of release, growers could make informed decisions on whether particular varieties are best suited to their farm or blocks within their farm. In order for this to occur a simple and reliable method to assess waterlogging tolerance of varieties is required. Four experiments were conducted as part of the process to develop a method to assess waterlogging tolerance of sugarcane varieties growing in pots. During the development of the method pots were immersed in water with low dissolved oxygen concentration (DO). The low DO concentration was maintained by the addition of fibrated sugarcane stalk, in order to increased biological oxygen demand. In later experiments water level was maintained at the soil surface through the development of a system that incorporated a float valve. Sugarcane shoot and leaf growth was reduced in waterlogging treatments. Tillering was reduced in some experiments, which appeared to be related to crop age when treatments were imposed. Overall, the methods used allowed anaerobic conditions to be maintained within the pot and plant response was typical for waterlogging. This provides confidence that this method could be used to assess tolerance of sugarcane varieties.