Introduction of Direct Seeding and Selection of Farmland in Rainfed Rice Fields in Small Water Sheds in Northeast Thailand

抄録

Paddy rice cultivation in rainfed areas in northeast Thailand has been practiced mainly by transplanting. However, the introduction of direct seeding is increasing in rainfed paddy fields for a variety of reasons, including saving on labor. To elucidate the relationship between the introduction of direct seeding, the selection of paddy lots, and precipitation in rainfed paddy field, we surveyed two small watersheds in Nong Saeng village, Khon Kaen prefecture, central-northeast Thailand. The surveys were carried out on a lot-by-lot basis between 2002 and 2004. In 2002, despite the lagging expansion of transplanting due to low precipitation in the early rainy season, direct seeding was not introduced. On the other hand, in 2003, direct seeding began before the transplanting area was expanded after rainfall in late August. In 2004, direct seeding began in the early rainy season of June and July. As to its relationship with topography, direct seeding was not conducted in the lower paddy fields in one watershed. However, the ratios of direct seeding increased in the middle and upper paddy fields in both watersheds in 2004. There were few households that did not continue direct seeding cultivation after introduction.