GanNan Grassland Sub-types Division Based On The Integrated Orderly Classification System

Grassland type is highly abstract and generalize of grassland resources entity . Grassland classification is the concrete practice of the grassland type theory. Chinese academic REN Ji-Zhou, HU Zi-Zhi, MOU Xin-Dai etc,drawed the advantage of the world's catagories ,and proposed the Integrated Orderly Classification System of Grassland (IOCSG). As a kind of more mature, facing the world one of the grassland classification, continuously has been applied and improved in the study of Chinese grassland. With the modern space information technology becoming increasingly sophisticated, global positioning system (GPS), remote sensing (RS) and geographic information system (GIS) technology etc, have already gone deep into grassland research work.Collected GanNan DEM datas which resolution are 1km×1km and 90m×90m, and twenty-two metorological data of GanNan and circumjacent area (the latirude and longitude, altitude, accumulative temperature and precipitation ), based on the IOCSG, with the help of geographic information system, It realizes grassland sub-types division of GanNan.The results show that:GanNan grasslands can be classified as 6 types of grassland , In 6 types the largest is the frigid humid rain tundra, alpine meadow.It covers 20994.8km~2, accounting for 57% ; frigid-temperate humid cold dampness coniferous forest is second, which covers 14174.6km~2, accounting for 38% ; Two kinds account for 95% of the total area, and are the most main grassland type of GanNan plateau.Year cumulative temperatures of greater than zero range from 1110 to 5000, Containing four zones: the frigid, frigid temperature, micro temperature, warm temperature. The temperature values are low in general. Distribution difference in the region is relatively big. Humidity from 1.2 to 11.0 , containing three grades: sight wetness,wetting, humid. It gradually decrease from southwest to northeast . The wetting degree is good overall.Water landform types of GanNan plateau has mainly four, and was sorted by area from large to small , erosion medium mountains, erosion high mountains, flood alluvial plain, alluvial plain. Erosion medium mountains cover 15679.8%, accounting for 44%; erosion high mountains 11475.2km~2, accounting for 32%; These account for 76% of the total area, and are the most main physiognomy type in GanNan. Flood alluvial plain 6526.7km~2, accounting for 18%, alluvial plains only 1781.1km~2, accounting for 6%.The results also show that: GanNan grasslands can be classified as 16 sub-types of grassland. In 16 types the largest is the frigid-temperate humid cold dampness coniferous forest-erision medium mountains. It covers 11297.1km~2, accounting for 33%; frigid humid rain tundra, alpine meadow-erision mountains is second, covering 10640.7km~2 and acconting for 31%. They are the most main sub-types in GanNan grassland.