Effect Of Different Land Use On Soil Nutrients In The Farming-pastoral Ecotone

The study used the field investigation and the indoor analysis to explored the status of soil nutrient contents which under three land use types:grassland,woodland and cultivated land in the Farming-pastoral ecotone which in Siziwang banner,Inner Mongolia.The principal component analysis method was used to comprehensively evaluate the soil nutrient,and the result was compared with the soil nutrient content in the Second Soil Survey in 1982,to analyze different ways of land use soil nutrient levels and various land use mode changes after 35 years of soil nutrient status.The results showed that:In the chestnut soil area,the soil organic matter(22.96 g/kg?28.74 g/kg),total nitrogen(1.39 g/kg?1.86 g/kg),alkali nitrogen(79.44 mg/kg?100.89 mg/kg)and available potassium(189.09 mg/kg?208.67 mg/kg)in the grassland with the landform type of hilly flat land and hilly sloping land were significantly higher than cultivated land.Soil organic matter,total nitrogen,total phosphorus and alkali nitrogen in meadow soil are the best in woodland,followed by cultivated land and grassland.And there is no significant difference in soil nutrient status between grassland and cultivated land in gray cinnamon soil area.On the whole,the soil nutrient content level of cultivated land is lower than that of grassland and woodland.According to principal component analysis,the soil nutrient comprehensive scores were:woodland(1.43)>grassland(1.08)>cultivated land(-0.50).Compared with 1982,the soil organic matter content of grassland and woodland was restored in 2017,with the highest increase of 104%,and the total nitrogen content of soil increased by up to 40%.And the soil organic matter and total nitrogen content in the cultivated land were mostly lost,the soil organic matter decreased by up to 33%,and the soil total nitrogen decreased by up to 27%.It can be seen that the maintain and restore soil nutrients of grassland and woodland are better than cultivated land.