This research aimed to study the economical impacts of using different types of irrigation water to produce wheat crop, through economic analysis of crop production and its costs, in order to maximize the income of each unit of water. The sample of study was choosed from wheat farmers in El.Sharkia Governorate. The results indicated that the productivity of one feddan irrigated with fresh water and groundwater was 18.09 and 18.08 ardab/fed respectively. It was 17.72 and 17.11 ardab/fed. for land irrigated with mixed water and drainage water respectively. The feddan irrigated with fresh water consumed 2672 m3 compared with 2922, 2841 and 3263 m3 for groundwater, mixed water and drainage water respectively. The feddan of wheat irrigated with groundwater gave the high- est return of income changed costs that was 1.233 pounds. The farmers in the study sample used quantities of irrigation water greater than the amount that achieve efficiency in the case of irrigation with groundwater rate of 6.23%, while the farmers in the stud[1]y sample used quantities less than the amounts that achieve efficiency by 1.27%, 10.9%, 7.9% for wheat irrigated with fresh water, mixed water and drainage water, respectively. The research recommended using these different qualities of water in irrigation, but in the context of a set of parameters with not of focusing on the use of agricultural drainage water directly due to the Low productivity per feddan and the low average of water unit production and the share of water unit of the net return, certain attention should be paid to mixing drainage water with Nile water, and also to treating drainage water before mixing with fresh water of River Nile.

Si application alleviates influence of some abiotic stresses on crop plants. Meanwhile, scarce information is avaiable about the significance of Si for helping the plants to overcome the injuries of N deficiency and herbicides pressure. Thus, two–year 2–field experiments were carried out in wheat. Experiment I involved three Si concentrations (Si0ppm, Si250ppm and Si500ppm) and two N levels(N100% and N50%). Experiment II examined four combinations of fenoxaprop–p–ethyl and Si: fenoxaprop–p–ethyl+Si250ppm and fenoxaprop–p–ethyl+Si500ppm (each either in sequence or in tank mixture), fenoxaprop–p–ethyl alone, hand weeding and weedy check. Under N deficiency (N50%), Si500ppm increased plant height as compared to the control. No significant differences in SPAD values were detected amongst Si concentrations under each of the two tested N levels. Si can partially alleviate negative N deficiency effect on wheat yield, causing its increase to level obtained under normal N supply. Si has no effect on weed biomass when applied with fenoxaprop–p–ethyl either in sequence or in tank mixing. The most promising treatment for maximizing wheat grain yield was the application of 100 kg N ha–1 (N50%) x fenoxaprop–p–ethyl+Si250ppm in sequence", which also, in the same time, means reducing both cost of crop production and environment pollution.