| A interpretation of five remote sensing images from 1987 to 2010 around the Qinghai Lake basin was made in this thesis. The grassland of cultivation mode and the farmland grazing mode of nearly 30 years were chosen as the research objects in north of the lake.This thesis aimed to research the variations differences of physical and chemical properties of two type soil to explore soil evolutionary changes. The result showed that the soil particle composition of grassland and farmland was sand clay loam, and sand and clay content of grassland was greater than that of farmland, but the sand content was less than that of farmland in lengthways profile of 0~60cm; 30 cm was a demarcation line for the total carbon and total nitrogen content of the grassland and farmland soil. Total carbon and nitrogen contents of grassland was greater than farmland above 30cm in lengthways profile, and the difference between the two was little below 30cm; the Xlf of grassland was smaller than farmland in lengthways profile of 0~60cm with small variable amplitude, 30 cm was a demarcation line for Xfd. Xfd of grassland is higher than farmland above 30cm, and reverse trend was below 30cm; farmland chromaticity value was higher than grassland on the whole profile of 0~60cm. Both the redness and yellowness had the same change trend in lengthways profile of 0~60cm, and the lightness value of grassland and farmland varied greatly. The pH value of grassland and farmland varied a lot in 10~40cm. The pH value of grassland was higher than farmland in 10~40cm, but there was not much difference below 40cm. |