RICE VARIETIES AS AFFECTED WITH DIFFERENT IRRIGATION PERIODS AND SUBMERGED DEPTHS IN THE NORTH NILE DELTA REGION

A field experiment was conducted at Sakha Agricultural Research Station Farm during the two growing seasons 2013 and 2014 to study the he effect of irrigation period, depth and cultivar on yield and water parameters for rice (Oryza sativa L.). The site located at Kafr EL Sheikh Governorate, Middle North of the Nile Delta. Two irrigation period treatments; 6 days (P₁) and 12 days (P₂) were tested. Three irrigation depths; irrigation till 3cm above soil surface (ASS) (D₁), irrigation depth till 5cm ASS (D₂) and the traditional till 7cm ASS (D₃) were tested. Three rice cultivars; Giza 177 (V₁), Sakha 101 (V₂) and Orabi (V₃) were tested. The important findings could be summarized as follows:
The highest values of irrigation water applied and then water duty were recorded under control treatment e.g. irrigation every 6 days and 7 cm depths (irrigation without any stress during the growing season, interaction between P₁D₃). On the contrary, the lowest values were recorded under interaction between P₂D₁ (every 12 days irrigation interval and 3cm depth during the growing season). The mean value of productivity irrigation water was increased under prolonged irrigation interval of 12 days plants comparing with other treatments. The highest mean values were recorded under interaction between P₂D₁ but the lowest mean values were recorded under interaction between P₁D₃ (highest water applied treatment)
The mean values for grain yield was significantly affected with irrigation period, depth and verities. For two periods, irrigation till 5cm (D₂) recorded the highest grain yield 4246.7 kg fed^-1, and 4394.3 kg fed.^-1 under 6 days as irrigation interval, and 2894.4 kg fed^-1., and 2866.6 kg fed^-1 under 12 days as irrigation interval in the first season and second seasons respectively. Orabi 1 recorded the highest values of grain yield under overall period and depth of water.  Yield components of rice; 1000 grain weight g., biological yield kg., straw yield kg., grain straw ratio and sterility % were decreased under water stress treatments in the second period (P₂) as compared with P₁, for water depths; D₁ compared with D₂ in the two period. For varieties, biological yield kg., and grain straw ratio only showed significant effect. Regarding, all studied growth parameters; panicle Length and plant height were increased with increasing irrigation water applied.
Moreover, water saving from interaction between P₁D₂ which increased yield with 7% with water saving with 16-18% as comparing with P₁D₃ (highest water applied treatment).