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 be-tween the two was little below 30cm; the Xlfof grassland was smaller than farmland in lengthways profile of 0～60cm with small variable amplitude,30 cm was a demarcation line for Xfd.Xfdof grassland is higher than farmland above 30cm,and reverse trend was below 30cm; farmland chromaticity value was higher than grassland on the whole pro-file 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 be-low 40cm.%通过对青海湖环湖区1987—2010年五期遥感解译,以湖区北部近30年耕作模式与放牧模式下草地和耕地为研究对象,研究两类土地土壤理化性质的变化差异来探求两种模式下土壤演替规律.研究结果表明:草地和耕地粒级都属于砂-粉砂级,在0～60cm内草地粉砂、粘粒含量大于耕地,而砂含量小于耕地;总碳和全氮以30cm为界,界上草地总氮、全氮含量明显大于耕地且差异明显,界下两者差异较小;草地低频磁化率在整个剖面上小于耕地且变幅较小,频率磁化率两者以30cm为界,界上耕地小于草地,界下则呈现相反态势;0～60cm内草地色度值皆小于耕地,其中红度和黄度值在剖面上变化趋势一致,而亮度值两者变化差异大;两者pH值在10～40cm段差异性明显,在该范围内草地的pH值明显大于耕地,40cm开始两者变化不大.
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