Growth and yield response of sweet potato (Ipomoea batatas var. batatas) under acid sandy soil, northeast of Thailand

Abstract

Sweet potato is one of the major crops grown for food, animal feed and industrial products. The yield obtained in the Northeast of Thailand is far below its genetic potential due to soil degradation, erosion, acidification, loss of organic matter, waterlogging and salinization causing nutrient deficiency. The objectives of this research are to investigate yield components, accumulation of nutrients and food nutrition of different sweet potato species under acidic sandy soil. The experiment with four replications was laid out in a farmer’s field at Phu Wiang and Nong Ruea District, Khon Kaen Province, where young smart farmers are interested to grow sweet potato. Trials were planted for 2 years using four species of sweet potato: (A) Honey Sweet, (B) Okinawan Orange, (C) Okinawan Purple and (D) Purple Sweet Lord. All plots were treated with a basal application of 1.56 t ha-1 of cow and poultry manure with 0.03 t ha-1 of chemical fertilizer formula (N12-P4-K4). An addition of 0.15 t ha-1 of chemical fertilizer formula (N12-P4-K20) was made at 15 and 30 days after growing. The results show that Okinawan Orange and Purple Sweet Lord were higher growth in Phu Wiang district than Nong Ruea district. If the cost and unit price are the same, Okinawan Orange will give farmers a higher return than Purple Sweet Lord. Regarding the leaf residues of Okinawan Orange and Purple Sweet Lord are suitable to be used for fish farming, because they contain the highest protein and carbohydrates.