Two field experiments were conducted during the two successive seasons 2004/2005 and 2005/2006 to assess the effect of irrigation length on wheat yield and wheat water use parameters. Five irrigation length treatments were examined; 100% of strip length (S.L) without cut off (Trt. A), 95% (Trt. B), 90% (Trt. C), 85% (Trt. D) and 80% S.L (Trt. E).
The obtained results revealed that:
Average of seasonal water applied were, in descending order as follows: A (2516.6) > B (2412.24) > C (2278.06) > D (2201.26) > E (2111.51) m3fed-1. Average water saving, in the two growing seasons, was 238.54 m3/fed. i.e. 9.48% for the best treatment 90% cut off in comparison with 100% without cut off. This water saving might be represented more than 0.5 mil. m3 of irrigation water for the wheat national cultivated area (2.5 x 106 fed.). Average water consumptive use could be arranged in descending orders: A (45.46) > B (43.35) > C (41.27) > D (40.01) > E (37.98) cm. The corresponding rates of consumptive use were0.27, 0.26, 0.24, 0.23 and 0.22 cm/day for the same treatments, respectively. The average values of consumptive use efficiency ranged between 91 to 94% for different treatments. Significant differences were found among the studied treatments regarding grain and straw yields as well as biological yield, 1000-grain weight and harvest index. The highest grain yield (2984.75 kg/fed. (7.1 ton/ha)) was scored with 90% cut off (Trt. C); i.e. watering till 90% of the cultivated wheat strip. The highest average of water utilization efficiency (WUtE) was about 1.61 kg/m3 which associated with the 90% cut off (Trt. C). On the other hand, the lowest value of about 1.16 kg/m3 was obtained from the control Trt A.