Geographical environment of Nujiang Lisu Autonomous Prefecture

Except for a few relatively flat mountain troughs and river alluvial beaches in Tongdian and Jinding, most of Lanping County are steep mountains with less cultivated land, and the reclamation coefficient is less than 4%. Cultivated land is distributed vertically along the hillside, and the slope of 76.6% cultivated land is greater than 25 degrees. Among the arable land, alpine land accounts for 28.9%, mountainous and semi-mountainous land accounts for 63.5%, and valley land accounts for 7.6%.

The northern part of the state is high in the north and low in the south, and the north-south trend of Dailika Mountain, Dulong River, Gaoligong Mountain, Nujiang River, Robbie Snow Mountain, Lancang River and Yunling Mountain are arranged in turn, forming a long and narrow mountain canyon landform. The highest point in the territory is Gawagapu, the main peak of Gaoligong Mountain, with an altitude of 5 128 meters, and the lowest elevation is Nujiang Valley with an altitude of 738 meters. Nujiang Prefecture is located in the longitudinal valley of Hengduan Mountain, the southern extension of Qinghai-Tibet Plateau on the roof of the world. This is a world-famous deep-cut landform. Due to the comprehensive influence of various soil-forming factors, the types of soil types formed in China are more complicated. There are 1 1 species, 29 soil genera and 55 soil species in Nujiang Prefecture, including 29 paddy soils and 35 dryland soils, which form the characteristics of horizontal, vertical and regional distribution.

The soil in Lushui, Fugong and Gongshan counties of Nujiang Prefecture is acidic, while the soil in Lanping County is alkaline. The soil is rich in organic matter and potassium. The river bank of the valley below the altitude of 1500 is mainly lateritic red soil and red soil; The semi-mountainous area at an altitude of about 2000 meters is dominated by yellow red soil and yellow brown soil; Alpine areas with an altitude of 2500-3000 meters are mainly brown soil and dark brown soil. More than 3000 meters, followed by gray-brown forest soil and alpine meadow soil. The weather in the state changes greatly and the climate is different. The climate of Nujiang Prefecture has the same characteristics as the monsoon climate of low latitude plateau, with small annual temperature difference, dry daily temperature, distinct wet seasons and indistinct four seasons. At the same time, due to the differences in topography and latitude, it is cold in the north, warm in the middle and hot in the south. The mountains are cold, the mountains are warm, and the riverside is hot; In some areas, the rainy season starts very early, the dry season is very short, and the warm season lasts for a long time, so there is no unique climate characteristics of early spring and three-dimensional climate.

The lowest altitude in Nujiang Prefecture is 738 meters, and the highest is 5 128 meters. The obvious altitude difference and complex regional environment affect the redistribution of heat conditions, and the temperature varies from place to place. Generally, it is located in the low-heat valley below 1400 meters above sea level, with the highest temperature and abundant heat. The annual average temperature is 16.8℃ ~ 20. 1℃, the hottest monthly temperature is 2 1.7℃ ~ 24.7℃, and the most Leng Yue temperature is 1 1.6538. Altitude 1800 ~ 2300m, annual average temperature15.1℃ ~1℃, hottest month temperature19.3℃ ~17. In mountainous areas above 2300m above sea level, the annual average temperature is above 1 1.0℃, the hottest temperature is above 17.8℃, the lowest temperature is below 3 1℃, and the extreme minimum temperature is below-10.2℃.