Growth and production of Cilembu sweet potatoes (Ipomoea batatas L.) varieties in the highlands with potassium fertilizer and pruning treatments

Abstract

Abstract The efforts to increase the productivity of sweet potatoes is applying of potassium and pruning treatments. The objective of the study was to evaluate the effect of potassium fertilizer and pruning treatments on the growth and production of Cilembu sweet potato varieties in the highlands (1.340 m above sea level). The study was conducted at “Balai Penelitian Tanaman Sayuran” (Vegetable Crops Research Institute), Tongkoh Village, Berastagi – Tanah Karo on September 2018 - March 2019, using a factorial randomized block design. The first factor was potassium fertilizer (0; 7; 14 and 21 g KCl/plant) and the second factor was pruning (without pruning; pruning till 3 tendrils; pruning till 2 tendrils and pruning till 1 tendril). The result of the research showed the treatment of potassium (7-21 g/plant) significantly increased the tuber size compared to without potassium fertilizer. The combination of 7 g KCl/plant and pruning till 2 tendrils treatments significantly increased the length of the main tendrils at 10-11 week after planting and tuber length per sample. While the combination of 14 g KCl/plant and pruning till 3 tendrils treatments produced the highest tuber weight per plot.