Study On Protection And Utilization Of Slope Cultivated Land In Arong County Of Inner Mongolia

As an important grain-producing area in China,the black soil area in Northeast China has a large area of cultivated land on its slope.Because of its special location and poor surface smoothness,soil erosion is very easy to occur,resulting in a decline in the quality of cultivated land and affecting agricultural production.This paper takes Arong County of Hulunbeier City,Inner Mongolia as the research object,through collecting data and field survey,selecting typical sloping farmland in the study area to set up protective utilization measures experiment,soil sampling,indoor experiment and data processing,and doing relevant research on land use structure,distribution and physical and chemical properties of arable land,and protective utilization of sloping farmland in Arong County.To analyze the influence of topographic factors on different land use types,investigate the distribution of cultivated land and its relationship with topographic factors,the correlation between soil nutrients and topographic factors,and the impact of different conservation measures on soil nutrients in sloping farmland.The main results are as follows:1.Forestland,arable land and grassland are the main land use types in the whole County.The proportion of distribution area to total land area is 43%,31.2%and 14.2%respectively.With the increase of elevation,the distribution area of grassland,cultivated land,construction land and water area gradually decreases,while the distribution area of woodland increases first and then decreases.Forest land is the largest area in the 8-15 degree area,accounting for 44.35%of the total area of forest land;grassland,cultivated land,construction land,water area and unused land are the largest area in the 0-5 degree area,accounting for 52%,50.34%,47.81%,45.97%and 50.77%of the total area respectively.The order of area distribution on each slope is semi-sunny slope>sunny slope>semi-shady slope>shady slope>flat land.There is no significant difference in the distribution index of land use types on each slope grade.2.In the range of 200-400 m and 0-8 degree,the cultivated land in the whole County is the most widely distributed area,accounting for 87.25%and 77.02%of the total area.The cultivated land on the semi-sunny slope is the most,accounting for 29%of the total area of cultivated land,and the cultivated land on the slope accounts for 49.38%of the total area of cultivated land.With the increase of elevation and slope,the area of cultivated land decreased;the soil nutrients of cultivated land were significantly correlated with elevation and slope(P<0.05),but not with slope direction(P>0.05).Among them,the contents of organic matter,alkali-hydrolyzed nitrogen and available phosphorus in soil nutrients were negatively correlated with slope(P<0.05).The soil nutrients of cultivated land in the study area were negatively correlated with slope degree(P<0.05).Slope is the most important topographic factor.3.The results showed that organic manure and maize straw could improve the physical and chemical properties of sloping farmland,but there was no significant effect on the content of available phosphorus and alkali-hydrolyzed nitrogen(P>0.05)in the treatment of straw returning.The combined treatment of organic manure and straw can not only make up for the shortage of straw returning measures,but also improve the physical and chemical properties of soil,and significantly improve soil nutrients(P<0.05).