Effect of water management and tillage practices on rice [Oryza sativa] yield, water use efficiency and physical properties of paddy soil in the Nile Delta

In Egypt, the major challenge facing the substantial requirements for rice (Oryza sativa L.) production is limited water resources. The experiment was conducted to determine the optimum irrigation frequency and tillage to maximize water use efficiency (WUE) and yield of rice. Two rice cultivars (Giza 177 and Sakha 101) were tested for the experiment. Four main tillage treatments were applied to both the rice cultivars: 1) chisel plough (2-passes) and wet leveling (T-1), 2) chisel plough (1-pass) and dry leveling (T-2), 3) moldboard plough, disc harrow and then dry leveling (T-3), 4) zero tillage (T-4). Rice crop was irrigated at four different intervals as sub-treatments: at every 3 days (i.e., continuous flooding) (1-1), 6 days (1-2), 9 days (1-3) and 12 days (14). As indicators for the performance of rice production; root volume, root/shoot ratio, grain yield and WUE were determined. Soil penetration resistance (SPR) and dry bulk density (BD) of post-harvest soils were also measured. Irrigation schedules and tillage types had profound effects on the crop and soil parameters. The main results are as follows: (1) irrigation interval of 6 days is recommendable for paddy rice in Egypt, (2) amounts of water can be saved through irrigation every 6 days with 8.6% for Sakha 101 and 13.7% for Giza 177 rice varieties compared with irrigation every 3 days, (3) based on grain yield, WUE and the ability to reduce soil compaction, the tillage practice T-3, recommended by Rice Research and Training Center (RRTC) in Egypt, is suggested to be reviewed in favor of T-1 which is commonly used by the rice farmers, (4) to increase rice productivity and water use efficiency. Giza 177 rice variety should be reviewed in favor of Sakha 101 variety.