Silicon is known to effectively enhance the resistance to drought mainly and stimulating the growth and development of many plant species. Two field experiments were carried out on a private farm at Sidi Barrani, Marsa Matrouh Governorate during two successive seasons of  (2011/2012 and 2012/2013). To evaluate the effect of organic matter and different sources of silicate , i.e calcium silicate (Ca-Sil),  sodium silicate (Na-Sil) , magnesium silicate (Mn-Sil) and potassium silicate (K-Sil) as foliar spray on role of silicate in water stress tolerance, growth, yield, yield components and chemical composition  of wheat plants under rain-fed conditions. This scientific aspect represents a new strategy technique for understanding the best usage of such materials under rain-fed conditions.  The obtained results indicated that, macronutrients and Si contents of wheat plant at 70 days from cultivation follows the following order  Potassium Silicate (K_-Sil)  < Calcium Silicate (Ca_-Sil)  < magnensium Silicate (Mg Sil)   < Sodium Silicate (Na Sil) . Generally, spraying silicate solution achieved significant increases in wheat yield and its components as well as N, P & K contents of grain and straw compared to the control (without addition any silicate), except for theweight of 1000 grains in both growing seasons. Potassium silicate gave the highest significant response for most plant parameters in both seasons followed by CaSil, MgSil and NaSil. Meanwhile, all yield components significantly responded to the application of compost in both successive seasons.  In most cases, the interaction effect between the factors under study was insignificant on wheat yield and its components as well as macronutrients content of grains and straw in both growing seasons.