الفهرس 
IntroductionOnly 14 pages are availabe for public view
 |  | from | 121 |  |  |
| | | from | 121 | | |
Abstract
Two field experiments were carried out at El-Bramoom Agricultural Research farm of Mansoura Horticultural Research station, Mansoura, Dakahlia Governorate, Egypt (+ 7m altitude, 30o 11- latitude and 28o 26- longitude), during the two successive summer seasons of 2014 and 2015. The experiments were designed to investigate the effects of nature potassium, and chemical potassium fertilizer treatments on plant growth, yield and its components, as well as chemical constituents and storability of tuber roots of sweet potato (Ipomoea batatas, L.) cv. beauregard.1-Vegetative growth characteristics -The highest values of plant length, number of branches/plant and leaf area/plant (cm2) were recorded in case of the treatments T15 (25% dose of kgK2O fed. +25% dose of feldspar /fed. +25% dose of Banana compost/fed + SDB). -The highest values of plant fresh weight Plant, dry weight and leaves number/ plant were obtained by T15. -The highest values of fresh weight of leave and fresh weight folige (gm)were found in treatment T15 .The highest values of leaves dry weight of / plant (gm) and Folige dry weight of / plant (gm) were found in treatment (T15):- Treatment (T15) gave the highest value as for Chlorophyll A, Chlorophyll B and total carotenoids in both seasons, while the other treatments gave the various values as for the previous characters but less than the values of T15 in both seasons. 2- Yield and its components:Treatment T15 gave the highest value as for weight yield/plant and number of tuber /plant in both seasons. Treatment (T15) gave the highest value as for marketable yield and total yield / fed and decreasing unmarketable yield in both seasons. 3-Tuber root characters:The highest values among treatments on average tuber roots weight (gm) were observed by T15 followed by T12 (25% kgK2O fed. + 50 % feldspar + SDB) in both seasons. 4-N,P K contents of leaves and tubers: The highest values of nitrogen of leaves were obtained by application of T3: (100% Banana compost) and T15 gave the highest values of N percentage on both seasons. But, T15 gave the highest value of P percentage. In addition, treatments T15 gave the highest value for K% followed by T14 in the first season and T11 in the second season. The highest significant values in nitrogen concentrations of tuber roots were obtained from the application of T3 and T15. The highest significant values in phosphorus was observed by (T15). the highest values were obtained by T11. And T15 in both season, while T2 and T4 gave rise to the lowest values in the first season and T4 produced the same results in second season.5-Organic composition The total carbohydrates, R-sugars %, N.R-sugars %, total sugar and carotenoids of sweet potato plants were positively responded to the studied treatments. However, the highest values of the previous parameters were recorded following application T15 in both seasons. Total carbohydrates and carotenoids of sweet potato plants were positively responded to the studied treatments. However, the highest values were recorded following application of in the both seasons 6- Quality of tuber roots during storage period: Data indicated that treatment 15 was the best among all treatments in reducing weight loss, decay and sprouting % over 120 days of storage ,that result was true for both seasons.