Two field experiments were carried out during the two successive winter seasons of 2015/2016 and 2016/2017 in the privet farm at Vegetables Farm at meet Faris village Dekarns, Dakhlia Governorate to study the effect of magnesium as application methods, and calcium rates as foliar application and the interaction between them on growth, yield and quality of potato cv. Spunta under clay soil conditions using furrow irrigation system . Fertilized potato plants with MgSO4 at 20 kg /fed. (SA) combined with 4% calcium chloride (FA) gave the highest values of plant height, number of leaves, leaf area/ plant and dry weight /shoot, N, P and K contents in leaves after 70 days form planting , number of tubers/plant, yield / plant and total yield/fed., dry matter, starch contents in both seasons without any significant differences with the interaction between MgSO4 at 4 % (FA) and CaCl2 at 2 or 4 % (FA) concerning the number of tubers/ plant in both seasons. While the interaction between MgSO4 at 4 % (FA) and CaCl2 at 4 % gave the highest values of Ca and Mg in tuber without any significant differences with MgSO4 at 20 kg /fed. (SA) and CaCl2 at 4 % (FA) in both seasons. In this regard, the increases in total yield/fed. were about 41.99 and 42.22 % for the interaction between MgSO4 at 20 kg /fed. (SA) and CaCl2 at 4 % (FA), followed by 34.19 and 33.52 % for the interaction between MgSO4 at 4 % (FA) and CaCl2 at 2 % (FA) than untreated plants in the 1st and 2nd seasons, respectively.