DETERMINING THE OPTIMUM IRRIGATION INTERVALS AND PLANT DENSITIES FOR SUNFLOWER UNDER DRIP IRRIGATION SYSTEM.

Abstract

Two field experiments were carried out in the modernized irrigation system network (drip irrigation technique) at the research farm at Sakha Agricultural Research Station, kafr El- Sheikh Governorate during the two successive growing seasons 2007 and 2008. The target of this present study was to investigate the impact of irrigation intervals on yield, its quality and some water relationships. Obtained data can be concluded as follows: - Seed yield was clearly increased by decreasing irrigation interval where the highest means values were recorded under the shortest interval (4 days) and the values were 1.03 and 1.08 ton/ fed. (2.45 and 2.57 ton/ ha) in the first and second growing seasons, respectively. Also, data showed that there wasn’t a pronounced difference among 8, 12 and 16 days irrigation intervals where the values were rather similar, but under 20 days irrigation interval, the value of seed yield was clearly decreased. Mean values of 1000 seed weight (g) were increased under irrigation interval each 4 days in comparison with other irrigation intervals 8, 12, 16 and 20 days where the highest mean values were 65.287 and 65.403 g in the first and second growing seasons, respectively. On the contrary, the lowest mean value was recorded under 20 days irrigation interval. In addition, data illustrated that the mean values of and head diameter was decreased by increasing irrigation interval up to 20 days. The highest mean values for the studied parameter was recorded under the shortest irrigation interval each 4 days in the two growing seasons, where the mean values for the studied parameter was 19.073 cm for head diameter. The highest mean values of plant height were recorded under 8 days interval in the first growing season, and under 12 days, in the second growing one and the mean values were 167.533 and 157.367 cm, respectively. On the other hand, presented data showed that there wasn't clear and standard relationship between plant densities and the studied parameters. Also, data illustrated that by elongation irrigation interval up to 20 days caused decreasing amount of water applied was found, where the highest mean values were recorded under the shortest interval of irrigation each 4 days and the values were1482.04 and 1556.8 m3/ fed in the first and second growing seasons, respectively. On the contrary, the lowest values were recorded under the longest irrigation interval 20 days between watering and the values were 1135.64 and 1110.0 m3/ fed. in the first and second seasons, respectively. Concerning the values of water utilization efficiency (W.Ut.E) which clearly affected by irrigation interval where the highest values were recorded under the shortest irrigation interval each 4 days where the values were 0.67 and 0.71 kg/ m3 in the first and second growing seasons, respectively. Under the other irrigation intervals 8, 12, 16 and 20 days the values were low comparing with the first treatment (interval of 4 days) but there wasn’t a standard and clear relationship between the other irrigation intervals (8, 12, 16 and 20) days. Data also illustrated that the highest mean values for oil content in seeds were recorded under 16 days between irrigations.