Two field experiments were performed during two consecutive summer seasons of 2014 and 2015 at El-Kassasien Hort. Res. Station, Ismailia Governorate, Egypt, to study the effect of organic manure sources (recommended chemical fertilizers, FYM, compost and chicken manure) and potassium humate ( without, soil application and foliar application) at the rate of 2 g/L ,as well as, different combination between them on plant growth, chemical constituents, yield and its components and storage root quality of sweet potato (Ipomoea batatas, L.) cv. Abees grown under sandy soil condition with drip irrigation system.
Application of organic manure fertilizers caused significant increases in growth parameter, yield and its components and mineral contents compared to control treatment (without organic fertilization). meanwhile, application of chicken manure at the rate of 5 m3/fed. achieved highest values of all aforementioned parameters, followed by the application of compost at the rate of 15 m3/fed and FYM at the rate of 15 m3/fed, in a descending order, respectively.
Spraying sweet potato plants with potassium humate significantly enhanced plant growth, yield and its components and mineral contents (NPK content in tuber root TSS, reducing and total sugar as well as total carbohydrate contents). In this respect, spraying plants with 2 g/L potassium humate attained the superiority impacts comparing the other treatments.
Hence, it can be concluded that fertilizing sweet potato plants by chicken manure at the rate of 5 m3/fed. in combined with spraying plants by potassium humate at the rate of2 g/L gave the highest values of growth, yield and its components and chemical constituents as compared to other interaction treatments.
Conclusively, this study showed that the highest yield of sweet potato storage roots and storage roots quality were obtained from chicken manure at 5 m3/fed., foliar application was potassium humate (2 g/L). The interaction between 5 m3 chicken manure and potassium humate as foliar application at the rate of2 g/L.