seasons to study the effect of preceding crop, rates and splitting of nitrogen fertilizer on bread wheat production and nitrogen use efficiency. The experiment was carried out in randomization complete block design (RCBD) using splitsplit plot arrangement with three replications. Cropping system (corn-clover-wheat and corn-fallow-wheat) were assigned in main-plots while nitrogen fertilizer rates (56.25, 75.00 and 93.75 kg N/fed) were allotted in sub-plots and splitting doses of nitrogen (two, three and four equal doses) were allocated in sub-sub plots. The obtained data showed that plant height, spike length, number of spikes/m 2 , number of grains/spike, weight of grains/spike, seed index, grain yield, straw yield and nitrogen use efficiency were significantly affected by cropping sequence in favor of planting wheat after clover (fahl berseem) in the two growing seasons except nitrogen use efficiency in the first season. Increasing nitrogen fertilizer rates resulted in significant increase in all previous traits except nitrogen use efficiency trait which was decreased by increasing nitrogen fertilizer rates in both seasons. Moreover, splitting nitrogen rates into four equal doses significantly increased all studied traits as compared to three or two equal splits in the two growing seasons. Also, all interactions had a significant effect on all studied traits in both seasons. The highest mean values of grain yield (27.47 and 28.22 ard/fed in the first and second seasons, respectively) were obtained from the sequence of corn-clover-wheat when received highest nitrogen rate (93.75 kg N/fed) which was applied at four equal doses.

IELD experiments were carried out at the Experimental Farm of ……Arab El-Awammer Research Station, Agriculture Research Center, Assuit, Egypt, during the two successive growth summer seasons of 2010 and 2011, to study the effect of two levels of phosphorus fertigation (23 and 31 kg P 2 O 5 / fed) divided into different doses (3, 6 and 9 doses) under different irrigation regimes (80 and 100% from pan evaporation). Water consumptive use, irrigation water use efficiency (IWUE), peanut yield and yield components were evaluated. The obtained results could be summarized as follows:The seasonal average quantity of irrigation water applied to peanut plants was 754.8 and 943.5 mm which equals 80 and 100% of pan evaporation, respectively. The crop evapotranspiration of peanut was 858.8 and 783.6 mm in the first and second seasons, respectively, as calculated by Penman Monteith equations.Peanut yield and yield traits were significantly increased with increasing the levels and doses of phosphorus fertilization. The highest values of WUE and IWUE were obtained from the highest level of phosphorus fertilization under irrigation with 80% of pan evaporation.Keywords: Peanut, Fertigation, Drip irrigation, Sandy calcareous soil, Phosphorus fertilization.The demands on agricultural products and water resources were increased steeply every where at the same time. Water is a limiting factor in any agricultural expansion depending on its quantity, quality and methods of water application. Growing of a fallow crop as peanut could be a good choice because of its high economic value and the benefit of legumes in the maintenance of soil organic N. Peanut is grown in many arid and semiarid regions during dry seasons therefore; it needs to be irrigated to produce economic yields. The application of fertilizers through the irrigation system (fertigation) became a common practice in modern agriculture. Increased yields, improvement in quality of the product, water and nutrient expense efficiencies and protection of the environment are some of the main characteristics of this method.