EFFECT OF CHOPPED RICE STRAW AND FOLIAR APPLICATION OF POTASSIUM AND PHOSPHORUS ON GROWTH, YIELD AND TUBEROUS ROOT QUALITY OF SWEET POTATO (Ipomoea batatas L.) GROWING AT LATE SUMMER SEASONS UNDER CLAY SOIL CONDITIONS

Abstract

Two field experiments were carried out at the experimental Farm, Faculty of Technology and Development(Ghazala farm), Zagazig university El Sharkia Governorate, Egypt during the summer season of 2017 and 2018 to investigate the effect of chopped rice straw and foliar spray with potassium and phosphorus fertilizers sweet potato cv. Minufiya 6 growing at summer seasons in clay soil, on growth, yield and quality. The experiment was set out in a randomized complete blocks design where including seven treatments, which were chopped, rice straw at 2kg/ridge only and in combinatory with potassium and phosphorus at 2 and 4 mll-1as well as control. The results indicated that application of chopped rice straw at the rate of 4kg/ridge with foliar spray of potassium and phosphorus at 4mll-1 was the most effective treatment for increasing the morphological trail of plants and its chemical composition. Also, this treatment recorded the highest values of total and marketable tuber root yield, as well as the best tuber physical characters( fresh weight, length and diameter) and maximum concentration of nutritive values, i.e. N, P, K, protein and starch percentage , besides the root content of carotene. Conclusively, it could be concluded that the obtained results, it can be recommended that the treatment of 4 kg/ridge of chopped rice straw and foliar application of potassium and phosphorus at the concentration of 4 mll-1 for improving the properties of clay soil and to access the vigorous plant growth, maximum production with the best tuber quality of sweet potato.