The water withdraw is a management practice frequently used by rice growers in the State of Santa Catarina, Brazil. The water removal aims at enhancing root development, to prevent lodging and to facilitate harvesting. On the other hand, water removal may stress the crop, reducing the number of tillers, decreasing the number of panicles per area and limiting grain yield. This experiment was performed to evaluate the effects of different periods of soil drainage at tillering on the agronomic traits of rice cultivars with contrasting cycles. The experiment was set in Pouso Redondo, SC, during the growing seasons of 2004/2005 and 2005/2006. Four periods of water drainage were tested: no drainage, soil drainage at tillering and re-flooding at 7, 14 and 21 days after soil drainage. Two cultivars were evaluated for each irrigation system: Epagri 106 (short duration) and Epagri 109 (late duration). Grain yield ranged from 7.833 to 9.239kg ha-1 (2004/2005) and from 3.984 to 9.040kg ha-1 (2005/2006). The water management system at tillering did not affect grain yield, yield components and rice milling yield. High pluvial precipitation during the drainage periods prevented drought, mitigating the effects of water management system on rice grain yield. The cultivar differences in growth cycle did not impact their response to the water management system. Soil drainage periods up to 20 days at tillering do not reduce the pre-germinated paddy rice productivity.
Oryza sativa; irrigation; tillering; grain yield
