Interaction between water regimes and potassium levels on growth, yield and water productivity of rice

摘要

The interaction between water regimes and potassium levels were studied using two rice cultivars, i.e. Sakha 104 and Giza 178 at the Experimental Farm of Rice Research and Training Center (RRTC), Sakha, Kafr El-Sheikh, Egypt during 2002 and 2003 rice seasons. Four water regimes namely, continuous flooding, continuous saturation, irrigation every 6 and 9 days and four potassium level namely 0, 57, 86 and 114 kg K_2O/ha were used. The experiments were laid out in a split split-plot design with four replications. The water regimes were in the main plots, cultivars were in the sub-plots. However, the potassium levels occupied the sub-sub plots. The main results reveled no major differences between continuous saturation and flooding on yield and its components. Prolonging irrigation intervals up to 9 days resulted in about a 17% reduction in grain yield. Giza 178 produced a higher dry matter, grain yield and water productivity than Sakha 104. The results showed also that increasing K levels up to 86 kg K_2O/ha increased significantly plant height, dry matter, yield and most of its components in both seasons. Additionally, significant amounts of irrigation water can be saved with minimum yield reduction if rice field can be continuously saturated all over the growing season. As a result, high water productivity could be obtained.