Effect of Fertilization and Pruning on Inulin Levels of Yam Bean

2. Department of AgroEcotechnologi, Agricultural Faculty of Andalas University, Indonesia

Abstract: Market demand for inulin as functional food tends to increase every year. Tuber of yam bean was one source of inulin, potential to be developed. Research that aims to determine the effect of fertilization and pruning on tuber yam inulin levels has been carried out in Duku, Padang Pariaman, West Sumatra, Indonesia and the Agricultural Product Technology Laboratory of Andalas University from January to July 2019. Using experimental methods, environmental design were Split Plot Design 44 with 5 replications. The main plot is pruning: without pruning, shoot pruning, flower pruning, shoot and flowers pruning. The subplots were NPK fertilizer (15:15:15) doses of 100,125,150 and 175 kg ha-1, the levels of inulin were tested by the Cysteine-Carbazole method. Data were processed using Statistics 8, LSD test continued at a level of 5%. The results showed that applying fertilizer with different doses combined with different pruning would produce tubers with different levels of inulin. The tuber inulin content has interval 9.36-24.39% with a degree of polymerization interval of 8.50-28.75. The highest levels of inulin were obtained by combining a 125 kg ha-1 NPK fertilizer dose with shoot pruning.