How Growth and Yield of Upland Rice Vary with Topographic Conditions: A Case of Slash-and-burn Rice Farming in South Konawe Regency, Southeast Sulawesi Province, Indonesia

摘要

Farmer interviews and a yield survey were conducted to elucidate the actual conditions of upland rice cultivation by the Tolakinese, the native people of Southeast Sulawesi Province, Indonesia. The interview results indicated that native farmers had been cultivated upland rice by slash-and-burn farming during the rainy season for personal consumption because of its good flavor, especially aroma, despite the low productivity. We categorized the topographical conditions in our survey field as either: flat, sloping, or depression. The growth and yield of upland rice varied according to these different topographic conditions. Our results of the yield survey suggest that uneven upland rice fields generate different cultivation environments and crop management strategies, which contribute to the variability in grain yields. Moreover, grain yield was highest under depression condition where more water was available, followed by flat and sloping condition. These findings suggest that soil water conditionsare important in rainfed upland rice cultivation.