Effect Of Swine Manure Application On Soil Quality Of Cultivated Land In Karst Area

The application of swine manure to field is an important part of eco agriculture in Guizhou Karst area.The aim of this research is to analyze the soil quality of application swine manure and utilization the swine manure in the large scale pig farm scientific and rational.Therefore,we adopt the method of long-term positioning field experiment and indoor analysis to discuss the physical properties,chemical properties and content of heavy mental in cultivated land.Finally,we used the comprehensive index method to evaluate the comprehensive effect of swine manure application on soil quality.Major findings are as follows.(1)The application of long-term swine manure have little effect on soil physical properties.The soil texture was middle loam soil and Physical clay content was between 38.4%~43.6%.The proportion of each particle size of soil mechanical composition is different,but they all are: Powder > Sand > clay.The soil non-water stability aggregates are dominated by > 0.25 mm aggregates,after in water analysis,< 0.25 mm micro aggregates are the main ones.The failure rate of aggregates is non-application of swine manure >application of swine manure.The soil aggregate failure rate of the soil without swine manure was the highest,reaching 64.47%.But soil stability was the best for 5 years of continuous application of swine manure,and the rate of aggregate destruction was the lowest,which was 24.73%.(2)The application of swine manure is beneficial to the accumulation of soil humus,enhancement of the soil mineral nutrients availability and soil microorganism enzyme activity.The indicators of soil fertility were overall applied for 10 years > 8years > 5 years > 3 years > 0 years and applied for 10 years of soil nutrient content is most rich,which is level I.(3)The accumulation of heavy metals in the soil is different in the study area.The size of the single pollution index is Hg > Pb > Zn > Cu > As > Cd > Cr.The most prominent accumulation is Hg.And the single risk factor index is As > Hg > Cd >Pb > Cu > Zn > Cr,As is a high risk of pollution.(4)With the application of swine manure in different time period,the degree of soil comprehensive pollution from the warning line reached a mild level of pollution,application 3 years as a warning line,application 5 years,8 years and 10 reached a mild level of pollution.However,the soil of potential ecological risk index was at low ecological risk level which application 10 yearsThose result showed that the soil structure and soil fertility were improved for a long time swine manure application in Karst area of Guizhou,but at the same time,some heavy metals were accumulated in the soil.Short term application of swine manure can improve the comprehensive quality of soil,while long-term application will reduce the comprehensive quality of soil.