Two field experiments were conducted at the Experimental Station, Faculty of Agriculture, Mansoura University, Egypt during 2007 and 2008 seasons. The objectives of this investigation is aimed to study the effect of water tension treatments, organic and inorganic fertilizer combinations and their interactions on quality, storability and chemical analysis of potato Spunta cultivar. Each irrigation treatments were conducted in a separate experiment. Every separate experiment laid-out in randomized complete block design with four replicates. Results indicated that highest averages of tuber length and diameter, nitrogen content in foliage and protein content in tubers were recorded with irrigation at irrigation at 26cb (5360.17 m 3 water/ha) i.e. 54.1% from field capacity in both seasons. Application of 60% mineral nitrogen fertilizer (238 Kg N/ha) plus 40% organic chicken manure (158 Kg N/ha) produced the highest averages of tuber length, tuber diameter, nitrogen content in foliage and protein content in tubers in both seasons. Adding 80% mineral nitrogen fertilizer (317 Kg N/ha) plus 20% organic chicken manure (79 Kg N/ha) recorded the highest averages of dry matter content after storage in Newalla & refrigerator. Results indicated that irrigation at 34cb (3449.62 m 3 water/ha) i.e. 45.8% from field capacity and adding 20% mineral nitrogen fertilizer (79 Kg N/ha) plus 80% organic chicken manure (317 Kg N/ha) produced the maximum values of dry matter content. It could be accomplished that irrigation at 26cb (5360.17 m 3 water/ha) i.e. 54.1% from field capacity as well as application of 60% mineral nitrogen fertilizer (238 Kg N/ha) plus 40% organic chicken manure (158 Kg N/ha) maximized averages of tuber length, diameter, nitrogen content in plant foliage and protein content in tubers.
