The Study About Season Pasture In Qinghai Province Based On GIS

Qinghai Province is located at the northeastern part of Tibetan Plateau. There are large amount of continuous mountains on the plateau, and the elevation there is high, with an average elevation over 3000m. The climate there is plateau-continental climate. Qinghai Province is the fourth largest grassland province in China, with 3.636×105km2 of natural grassland, which is 50.34% of the area of whole province. Livestock husbandry is the mainstay industry of the province, as well as the economic basis of the live and development the population there.Grassland livestock husbandry in Qinghai province is highly dependent on environment, featuring a significant seasonal utilizing of pastureland. The seasonal utilizing of pastureland refers to a pasturing method that divides grassland with seasonal category, and perform a cycle that grazing on different pastureland that following the change of seasons. Seasonal utilizing of pastureland is a key feature of the grassland livestock husbandry in the western part of China. This method is based on the long experience of local herdsmen, and is somewhat scientific. The difference of foraging need between livestock, the seasonal and territorial difference of growth between various species of grass, can be coordinated with this method, for the optimized economic and environmental development. Accurate learning of the seasonal utilize of grassland can be a scientific support to the management and planning of grassland livestock husbandry.This study is based on GIS, with Qinghai province as study area. The research approach of dividing seasonal pastureland is based on the significant elevation difference in study area and the vertical zonality in the growth and utilizing of forage grass. Another approach is to take the influence of population into consideration, and to modify the main approach with the factor population distribution. The combination of the two approaches is the new dual-factor method of dividing seasonal pastureland. With the spatial analysis module of GIS software, simulation model is constructed for 8 areas of Qinghai province, which taken lkm2 as minimum spatial resolution, to study the seasonal utilizing of grassland in study areas, and to perform an accurate divide of seasonal pastureland. An assessment of accuracy of the classification of seasonal pastureland and the area ratio of two types of seasonal pastureland was also conducted. The result showed that the total areas of grassland in Qinghai is about 3.8×105km2, total areas of winter and spring seasonal pastureland is about 1.7×105km2, which is 44.62 of total areas of grassland; total areas of summer and autumn seasonal pastureland is about 2.0×105km2, which is 52.52% of total areas of grassland; other type of seasonal pastureland is about 0.1 X 105km2, which is 2.87% of total areas of grassland. Accurate assessment showed that the classification accuracy of the seasonal pastureland map of Qinghai province is 66.65%, and the ratio between two main categories of pastureland is very close to the field survey in 8 areas, that can accurately reflect the actual utilization of the grass season.