Effects of harvest date, NK fertilization and curing on storability and chemical constituents of sweet potato tuberous roots during storage [electronic resource].

Includes references.

Two storage experiments were carried out at the Post Harvesvt Center, Faculty of Agriculture, Alexandria University. The objective of these experiments was to follow up the effects of some pre-harvest treatments such as; two harvest dates (after 120 and 150 days from transplanting) and four NK fertilizers treatments combinations (control, 20-36. 40-0 and 40-72 Kg N-K2O/fed),as well as two curing treatments (curing and non-curing) on storability and chemical constituents of tuberous roots of sweet potato during storage periods. The obtained results illustrated that delaying harvesting of tuberous roots lowered the percentages of weight loss, decays and dry matter throughout the first two storage periods,' 30 and 60 days. Whereas, increasing the storage period up to 120 days with late harvested date significantly increased the percentages of decays, weight loss, total sugarss, reducing and non-reducing sugars, sucrose and total carotenoids, but decreased the tubers' starch content. Pre-harvest fertilization with 20-36 Kg N-K2O/fed produced tubers with the highest contents of total sugars, non-reducing sugars, and sucrose at the beginning and end of storage. Whereas, increasing the level of pre-harvest application of NK lip to 40-72 Kg/fed, increased the percentages of decays, reducing sugars and starch as well as total carotenoids content, but decreased the crude fibers content at the end of storage period. Curing of sweet potato tubers, before storage, lowered the percentages of weight loss and decays during storage, meanwhile, the tubers' dry matter content did not significantly respond to curing process Moreover, curing the tuberous roots increased percentages of total sugars, non-reducing sugars, and sucrose, as well as total carotenoids and lowered the percentage crude fibers at the end of storage. Generally, the cured tuberous roots of sweet potato plants which were fertilized with 20-36 Kg/fed of N-K2O and harvested after 150 days from transplanting. lowered the percentages of weight loss and decays after 30 and 60 days of storage periods, as well as significantly increased total sugars, non-reducing sugars and sucrose contents at the end of storage.

Summary in Arabic.

1