Field experiments were carried out on clay soil at El-Gemmeiza Agricultural Research Station, El-Gharbia Governorate, during two consecutive growing seasons, summer season 2010 and winter season 2010/2011.  The experiment was designed using a randomized complete block design as split-split plot with three replicates to study the effect of three irrigation intervals with phosphorus application to soil and foliar spray of ascobin (ascorbic and citric acids) to plants on growth and yield of maize, wheat crops and some soil properties. Furthermore economical analysis was done by calculating the net income for every treatment. The obtained results could be summarized as follows:- 1-     Increasing irrigation intervals significantly increased values of soil bulk density and water use efficiency, while total soil porosity, hydraulic conductivity, soil moisture content just before harvesting and water consumption take the opposite direction during the two growing seasons. 2-     Decreasing irrigation intervals significantly decreased soil pH, electrical conductivity (EC), soluble cations and anions, total soluble salts (TSS) and sodium adsorption ratio (SAR) and significantly increased available nutrients N, P, K, Fe, Mn, Zn and Cu in the soil. 3-     Increasing phosphorus applications rate significantly increased water consumption, water use efficiency, yield and its components, electrical conductivity (EC), availability of macro and micronutrients of the soil and its concentrations and uptake in grains in both seasons. 4-     Foliar application of ascobin significantly increased water consumption, water use efficiency, concentrations and uptake of macro and micronutrients N, P, K, Fe, Mn, Zn and Cu of maize and wheat grains and yield and its components. While foliar application with ascobin had no effects on soil physical or chemical properties. 5-     Cost benefit analysis revealed that the most valuable combination is irrigation every two weeks in the first season (maize plants) and every four weeks in the second one (wheat plants) at 100% of the recommended dose of phosphorus in both seasons with ascobin foliar application.