الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
This investigation was carried out on maize (SC 129) cultivar for two summer seasons (2011 and 2012) in an experimental field at Al-Ibrahimia district, Sharkia Governorate, in order to optimize the use of irrigation water through prolonging the irrigation interval to 18 instead of 14 days using organic manuring with FYM (20 m3/fad) or compost (5 ton/ fad) as measures of improving the soil physical properties particularly the water holding capacity. Three N fertilization levels (20, 60 and 120 kg N/fad) were served to maximize the maize yield and its growth and yield attributes. Irrigation interval treatments started from the 3rd irrigation (48 days after planting) when the nitrogen fertilization was completed.
With very few exceptions, neither the irrigation interval nor the organic manuring had significant effects on maize growth at time of silking. However, the physiological performance of the 14 days plants interval post silking was more than those of the 18 days plants where the contribution of current photosynthates and newly reduced nitrogen in building up ear dry weight was higher by the formers than by the latters. However, the grain and stover yields/ fad produced by both irrigation intervals were not significantly different. Though the beneficial effect of organic manuring was not detected on the growth of maize plants either at or post silking, significantly higher grain and ears yields/ fad were obtained due to organic manuring with FYM compared with the check or compost organic manuring treatments. Finally, each N increment produced a significant increase in all maize growth and yield attributes and hence grain and stover yields/ fad at harvest. High N fertilized plants served more stored photosynthates in building up ear dry weight than low N fertilized ones but, in both cases the contribution of current photosynthates was always higher than the stored ones. Significant interactions could be detected to affect some of the growth and yield attributes of maize, however, the most interesting was the interaction between irrigation interval and organic manuring which affected maize grain and ear yields/ fad in the second season. This interaction indicated a beneficial effect due to organic manuring with FYM where prolonging the irrigation interval did not cause any significant decrease to these yield averages except in the check un manured plots. This favourable effect was attributed to an improvement in soil fertility from chemical and biological rather than physical properties points of view as organic and un organic manured plots had an almost similar soil moisture contents before the 3rd to the 7th irrigation. The obtained results from this study recommend scheduling four irrigations in 18 days interval starting from the 3rd irrigation and soil incorporation of 20 m3 FYM/ fad before planting and addition of 120 kg N/ fad as 20 kg N/ fad at planting and the rest equally before the first (20 DAP) and the second (34 DAP) irrigations. Therefore, the total number of irrigations is six only i.e. saving one irrigation without any significant decrease in maize grain yield or the content of grain from protein.