| The comprehensive management of rocky desertification is of great significance to the construction of ecological civilization and sustainable development in the karst area of southwest China.This research is based on the basic theme of karst ecological construction and regional economy.Taking the typical representative of the southwest China karst plateau gorge rock desertification comprehensive restoration demonstration area(Guanling-Zhenfeng Huajiang study area)as the research object,the characteristics of soil carbon pool under nine typical rock desertification restoration measures were studied.Taking Guiyang,the capital of Guizhou Province as the research object,to study the carbon emission characteristics of its typical agricultural activities.Finally,referring to the results of the predecessors' comprehensive management of rock desertification and combining the two previous studies,the Guanling-Zhenfeng Huajiang study area was taken as the object to study the comprehensive technology and model of rock desertification management.It is expected to provide a theoretical reference for the governance of karst rocky desertification and poverty in southwest China,rural revitalization and the construction of beautiful China.The main findings are as follows:(1)In this study,the soil organic carbon,total nitrogen content and stocks under nine measures of rock desertification control all showed that theSabina chinensisforest,mingled forest of Sabina chinensis and Ligustrum lucidum were larger than the other seven measures of rock desertification restoration.On the soil profile,the contents and stocks of soil organic carbon and total nitrogen decreased with the increase of soil depth,and showed a certain surface aggregation effect.The soil carbon-to-nitrogen ratio of each restoration measure was between 7.23 and 16.92.Except for Zanthoxylum bungeanum forest,Sabina chinensis forest,mingled forest of Sabina chinensis and Ligustrum lucidum,and slope farmland,the vertical profile showed a decrease with the increase of soil depth.Correlation analysis shows that soil organic carbon and total nitrogen have a very significant positive correlation(P<0.01).Soil bulk density,as an important factor in soil physical and chemical factors,has a very significant negative correlation with soil organic carbon,total nitrogen,and carbon-to-nitrogen ratio.The relationship(P<0.01),>2 mm gravel content also has a very significant correlation with soil organic carbon and total nitrogen content(P<0.01),and soil pH has no significant correlation with each physical and chemical index.(2)In this study,there were differences in the contents of soil organic carbon fractions(water-soluble organic carbon,easily oxidizable organic carbon,particulate organic carbon,light fraction organic carbon,and heavy fraction organic carbon)in the nine types of rock desertification restoration measures,all of which were shown as Sabina chinensis forest,mingled forest of Sabina chinensis and Ligustrum lucidum,and Zanthoxylum bungeanum forest is larger than the other six restoration measures.On the soil profile,the contents of each fraction of soil organic carbon in each restoration measure showed a decrease with the depth of the soil.There are differences in the ratio of soil organic carbon fractions to soil organic carbon in each restoration measures.Among them,the proportion of soil water-soluble organic carbon is between 0.27% and 0.76%.On the vertical section,the change trend of soil water soluble organic carbon proportion is opposite to that of soil water soluble organic carbon content,which increases with the increase of soil depth.Soil oxidizable organic carbon accounted for 10.74%~22.12%.On the soil profile,except for slope farmland,which increased first and then decreased with the depth of the soil layer,all other restoration measures showed an increase with the depth of the soil layer.The proportion of soil particulate organic carbon is between 9.57% and 50.52%,the light fraction organic carbon is between 2.28% and 11.06%,and the heavy fraction organic carbon is between 55.19% and 74.52%,this three fractions of soil profile did not show the same change rule.Correlation analysis showed that the soil organic carbon and soil water soluble organic carbon,easy oxidation of organic carbon and particulate organic carbon,light fraction organic carbon,and heavy fraction organic carbon were significantly positive correlation(P<0.01),and between the two fractions were also very significant positive correlation(P<0.01),indicating that soil water soluble organic carbon,easy oxidation of organic carbon and particulate organic carbon,light fraction organic carbon,and heavy fraction organic carbon can be used as reaction effective indicator of soil organic carbon.(3)In this study,slope farmland was used as a control to calculate the soil carbon pool management index and related indicators of each restoration measure.The study found that,except for the Pennisetum sinese,the soil carbon pool management index of each measures has increased to varying degrees.Based on the research on the soil carbon pool management index of the nine types of rock desertification restoration measures in the study area,and combined with the previous research on the soil organic carbon,total nitrogen and other physical and chemical indicators and the soil organic carbon fractions related research,it is believed that Zanthoxylum bungeanum forest can be used for ecological restoration of karst rocky desertification in southwest China and economic species that are prioritized for mountain agriculture development.In addition,there is a significant or extremely significant correlation between the soil carbon pool management index and various physical and chemical properties and soil organic carbon fractions.Therefore,this paper believes that the soil carbon pool management index can be used as an effective indicator to reflect soil quality.(4)In this study,Guiyang agricultural carbon emissions from 2007 to 2016 showed a general downward trend,from 532,000 tons in 2007 to 496,700 tons in 2016,an average annual decrease of 0.75%.Among the three major types of carbon sources,rice cultivation produces the largest carbon emissions,at 67.37%,followed by livestock and poultry farming,with carbon emissions accounting for 17.08%,and finally,agricultural land inputs,accounting for 15.55%.The research on the elasticity of the decoupling of agricultural carbon emissions and economic growth in Guiyang from 2007 to 2016 shows that in the past decade,the types of decoupling between agricultural carbon emissions and agricultural economic growth in Guiyang showed strong decoupling,weak decoupling,strong negative decoupling,There are 4 states of expansion negative decoupling.The decoupling type is mainly strong decoupling.According to the carbon emission data of Guiyang City from 2007 to 2016,using MATLAB software to predict the agricultural carbon emissions of Guiyang City from 2017 to 2026,the results show that the agricultural carbon emissions of Guiyang City have decreased year by year,from 501,400 t to 476,600 tons per year from 2017 to 2026.(5)The comprehensive management of rocky desertification is an important measure for the construction of ecological civilization and sustainable development in the karst area of southwest China.This article follows the concept of natural development and uses small watersheds as the basic unit..Based on the characteristics of soil carbon pool and carbon emission characteristics of karst typical agricultural activities based on 9 typical rocky desertification control measures in Guanling Huajiang Research Area in Guizhou,this paper takes Guizhou Guanling Huajiang Demonstration Area as the research object and optimizes the respectively allocate three technology systems for species selection and breeding,foreign exchange management technology system for complex management and agricultural land management,of ecological carbon sink forest planting technology system,mixed agroforestry management technology system,artificially improving soil carbon sink technology system,habitat adaptive vegetation restoration technology system,and agricultural land management increasing sink technology system.Based on this,four rock desertification comprehensive management models were constructed,including ecologically-leading and accelerating sink-restoration vegetation restoration model,economic forest and grass-increasing sink-restoration vegetation restoration model,grain-based production and sink-increasing planting model,and derivative industry development and sink-increasing governance model. |
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