关键词: 水稻, 水稻

Abstract: In order to uncover the change direction and extent of land use in Songhua River Basin in the first decade of 21th century at larger scale, the author analyzed land-use characteristics in Songhua River Basin using remote sensing (RS) maps of 2000, 2005 and 2010, respectively. Based on RS-derived maps, three change matrices were constructed for detecting land-use change between 2000 and 2005, between 2005 and 2010, 2000 and 2010 through overlay analysis. Three sub-basins were compared during different time periods to analyze spatial pattern and spatial-temporal variation of land use in the basin. The outcomes indicated that wetland greatly decreased slightly from 2000 to 2010, especially in Nen River. In contrast, land for construction greatly increased in the same period, and all three sub-basins present the trend of increasing, especially which of the Second Songhua River, increased by 11.52%. Farmland slightly increased from 2000 to 2010, but significant different were identified among three sub-basins. Farmland in Nen River obviously increased, but decreased in two other sub-basins. The dynamic conversion process of land use was dominated by wetland-cultivated land and cultivated land-construction land. The forestland had relative high retention rates. In spatial scale, the types of land use mainly were changed in the upstream plains of Nen River and downstream plains of Songhua River mainstream. The results also indicated that: the cross conversion in the Nen River frequently occurred among the types of land use, and a large part of internal conversion in the Ⅰ categories of land use had happened. But conversion occurred among only a few the types of land use in the Songhua River mainstream.