Study On Characteristics Of Vegetation And Soil Under Different Ecological Rehabilitation Measures In Karst Area

Guizhou Puding County is an example as the typical rocky desertification control demonstration in this paper.The species composition and diversity,partial biomass on the ground and physical and chemical characteristics of the soil are analyzed by conducting field surveys and sample collection with the vegetation and soil under different Ecological rehabilitation measures,The optimal Ecological rehabilitation measures were discussed by gray relational analysis,This provide the theoretical basis for promoting Ecological rehabilitation in Puding County as well as karst rocky desertification area.The main results are as follows:1.The vegetation characteristics under different Ecological rehabilitation measures(1)The species compositionIn the restoration of vegetation,the main species are dicotyledonous plants,and the next to the leaf plant,including Compositae,Rosaceae,Leguminosae and gramineae.The species composition are 61 species under the cultivated land,the main dominant species of the community structure are Shiyanfeng,Octagonal maple,Imperata cylindrica,Arthraxon in the cultivated land;there are 29 families and 43 species in the cutover lands,and dominant species.of the community are light birch,bamboo leaf pepper,shell pepper,Clematis orientalis in overcutting land;There were 47-62 species under the different measures,and Loquat,Pear,Mountain rat Lee,South China Mao fern is the main dominant species of community structure in the economic forest among the measures;There were36-49 species and the main species of community structure was dominated by Platycladus orientalis,Platycladus orientalis,Phyllostachys praecox,Leafberry and Arthraxon in the cypress grov.The species is more under the measures of aquasorb+ mulching and mulchinging.(2)The species diversityWith the increase of recovery years,the total species diversity Shanonon-Wiene(H)index of the returning farmland showed an increasing trend,but the overcut land was not obvious.The total species diversity index(H)about community range from 0.99 to 1.24 in the economic forest,the size of theorder is: aquasorb+mulching> mulching> aquasorb> fertilization>control group.The range of total Shanonon-Wiene(H)index is from 0.96 to 1.44 in cypress grove,the size of the order is:aquasorb+mulching>mulching>replacing soil>control group>fertilization>water retaining agent,Mulching and water retaining agent have great influence on species diversity at different levels among these measures.(3)The aboveground biomassThe rate of biomass growth can be a better measure of plant biomass: the cultivated land was23.84%,All land is 67.61%,the economic forest is 28.88-79.34%,the size of the order: mulching>fertilization> control group> water retaining agent > aquasorb+mulching,the cypress forest is4.44-18.92%,the size of the order: fertilization> replacing soil> quasorb+mulching> mulching>cwater retaining agent > control group;fertilization and mulching have greater influence among them.2.The soil characteristics under different ecological rehabilitation measures(1)The physical property of SoilThe total porosity of soil is 55.70-64.50%,and the bulk density is 0.89-1.15g/cm3,all measures have improved effect on cypress forest,especially,aquasorb+mulching and water retaining agent are better,however,only mulching has improving effect in the economic forest.(2)Soil chemical propertyThe range of soil organic carbon is from 23.63 to 54.13g/kg,and decrease with the increase of soil depth,The size of the order is : the overcut land>the cypress grove>the economic forest>cultivated land;All the measures can promote the organic carbon accumulation in plantation,and mulching and fertilization are better among them.The total nitrogen content range from 0.34 to 1.44g/kg,and gradually decrease with the increasing of soil depth,the size of the order:the cypress grove> the cultivated land>the economic forest> the overcut land,water retaining agents help increase the content of total nitrogen.Total potassium content is from 1.31 to 15.4g/kg,the size of the order: the overcut land>the economic forest>cultivated land>the cypress grove.The total potassium content decrease with the deepening of soil depth under the cultivated land and the measures of mulching and water retaining agent,while show an increasing trend in the other measures.Mulching and water retaining agent decreased the leaching loss of total K,accompanied by a small amount of soil erosion.The content of available nitrogen is from 76.64 to 315.77mg/kg,and gradually decrease with the increasing of soil depth,the size of the order:the overcut land>the cypress grove>cultivated land>the economic forest.All measures have helped increase in soil available nitrogen in the cypress forest,Among them replacing soil and covering are best,however,only mulching has improving effect in the economic forest.The content of available potassium is from36.81 to 262.64mg/kg,and gradually decrease with the soil depth deepened,except the overcut land,the size: the overcut land>the economic forest>cultivated land>the cypress grove.The phosphorus variation with depth is smaller except for covering,The phosphorus content of these measures are smaller than the control group in the economic forest,especially the water retaining is most.3 Comprehensive benefits of ecological rehabilitation(1)The maximum grey correlation degree of natural restoration is clear cutting,because clear cutting only destroys the surface part of vegetation,it can achieve rapid regeneration of vegetation under suitable conditions(2)The correlation degree of economic forest restoration is: mulchinging and water retaining agent>mulching>control group>fertilization>water retaining agent.The correlation degree of Ecological rehabilitation of cypress forest was: water retaining agent>mulching>guesting land>fertilization>mulchinging and water retaining agent>control group.The measures can promote Ecological rehabilitation,the best effect is water retaining agent,followed by mulching?guesting land.(3)Consider synthetically:mulching is the best measures in artificial promotion,more suitable for Ecological rehabilitation in Karst area,We should give more attention on it.