Water balance in dry seeded and puddled transplanted rice in Punjab, India

摘要

Rice systems that increase production using less water are urgently needed, especially in North West India where ground water is over-exploited. Replacing the traditional puddled transplanted rice (PTR) with dry seeded rice (DSR) is often proposed asa means of increasing water productivity and saving water. A field study was conducted in Punjab, India, in 2008 to investigate components of the water balance and water productivity in DSR and PTR with different irrigation schedules. Irrigation scheduling was based on different thresholds of soil water tension (SWT. The input water productivity (WP_(i+R)) of rice was significantly higher in DSR irrigated at 20 kPa (0.71 g/kg) than in all other treatments followed by PTR at 20 kPa (0.50 g/kg), The differences in WP_(I+R) between PTR and DSR at 20 kPa were largely due to reduced seepage. However, deep drainage beyond 0.6 m soil depth was higher in DSR, presumably due to the absence of hard pan in the non-puddled system. There was no significant difference in evapotranspiration (~ 600 mm) between DSR and PTR when irrigation was scheduled on the basis of SWT.