INFLUENCE OF ADDITION METHODS OF FULVIC ACID AND FOLIAR SPRAY WITH POTASSIUM SOURCES ON PRODUCTIVITY AND QUALITY OF POTATO CROP

Two field experiments were carried out during the two successive winter seasons of 2015/2016 and 2016/2017 in a private farm at meet Faris village, Dekarns, Dakhlia Governorate, to study the effect of fulvic acid as application methods ( without, soil application at 4 kg /fed. and foliar application at 5 g / l) and some sources of potassium (potassium sulphate, potassium silicate, potassium chloride and potassium citrate) at 1% K2O as foliar spray and the interaction between them on growth, yield and quality of potato tuber cv. Spunta under clay soil conditions using follow irrigation system . Results indicated that, the interaction of fulvic acid at 4 kg/fed. as soil application (SA) with K silicate as foliar spray recorded the highest values of plant height, number of leaves and dry weights of potato plants. It also exerted superior recorded of N, P and K concentration in shoots and its uptake after 70 days from planting , number of tuber/ plant, yield (kg)/ plant and total yield ( ton) /fed., dry matter content in tuber, TSS, starch and K content in tuber at harvesting time. In this connection, it was followed by the interaction between fulvic acid at 5 g/liter as (FS) and silicate potassium in both seasons. Meanwhile, the lowest values of abovementioned traits were recorded with the interaction between treatments of fulvic acid non addition and spraying potato plants with K sulphate in both seasons. In this regard, the increases in total yield/fed. were about 38.90 and 45.14% for the interaction between fulvic acid as soil application and foliar application of K silicate, followed by 32.66 and 36.33 % for the interaction between fulvic acid as soil application and K citrate foliar application and 31.95 and 36.67 for the interaction between fulvic acid as foliar application at 5 g/l and K silicate foliar application than that plants which sprayed plants with K sulphate only in the 1st and 2nd seasons, respectively.