Effect of three water treatments on growth of rice variety IR36

Abstract

Rice (Oryza Sativa L.) variety IR36 was grown under three water treatments namely: saturated sand, water table held at 15cm below the sand surface and water table at 30 cm below the sand surface. The growth period was 6 weeks with plants harvested at two week intervals. Growth parameters measured included total number of roots, length of roots, shoot dry mass, root dry mass and number of tillers. Moisture content at a depth of about 3 cm below the surface of the sand was also determined. There were no significant differences in root dry mass for the treatments but shoot dry mass was significantly greater under the saturated treatment than under the 30 cm treatment but there was no significant difference between those under the saturated treatment and the 15 cm water table treatment. Length of roots greater than 30 cm long were significantly greater under the 30 cm treatment than the others but number of roots greater than 30 cm long were significantly greater under the saturated treatment than the others. Tiller numbers were significantly greater under the saturated treatment than under the 30 cm treatment. Generally growth was in the order saturated > 15 cm water treatment > 30 cm water table treatment. Water table control was able to sustain growth of rice over a period of six weeks after sowing, however growth under saturated conditions was better than the others.