| Fujian Changting is the most serious regional of soil erosion history,size and degree of harm in Southern Red zone,and is one of the most typical regions of the country eroded red soil.After decades of unremitting efforts,Changting soil erosion control made great achievements and formed a number of soil erosion governance models with Changting characteristics.However,due to the long-term damage to vegetation,partly eroded area of red soil intensity is not to be governed.Topsoil fine particles of the intensity erosion area were washed depleted,left a large number coarse-grained gravel in the surface,the soil nutrient was poor,water holding and fertilizer supply capacity is poor too.Summer extreme high temperature led to the surface high temperature and seasonal drought of erosion area,soil dry thermalization serious,the bare surface lack of vegetation cover in Changting temperature up to above 60?,extreme surface temperatures even up to above 70?,which plants are usually difficult to survive.Although in these intensity red soil eroded region has carried out a large number of measures to restore vegetation,however,due to lack of understanding of the limiting factors of vegetation restoration in intensity erosion area,the governance with little success at present,and become the "hard nut to crack." of Changting Soil Erosion governance.Therefore,how to monitor the variation of environmental factors in Changting red intensity soil erosion area,Screening limiting factor effect vegetation restoration of the regional,has become a major issue that must be resolved in the current erosion areas of the intensity of the soil erosion area..In view of this,this thesis based on the long term vegetation restoration study in Changting red soil eroded region of tutor group,use vegetation degradation stages such as Evergreen broadleaf forest,inefficient forest,degraded bare and vegetation restoration stages such as grass and shrub forest,coniferous and mixed coniferous forest as experimental ecosystems.Through positioning observed the different degradation and recovery phases like small climatic factors,soil factors and vegetation factors,analyzed the variation of erosion intensity of vegetation degradation and restoration of environment factor and through the the principal component and associated analysis of environmental factors to screened the limiting factor effect the vegetation restoration in Changting red intensity soil erosion area.Based on this,Select the soil of the Changting red intensity soil erosion area,configuration simulation of different proportions of soil particles in indoor,simulated the ecological environment of Changting red intensity soil erosion area,by different plant seeds germination experiment,determine the environmental factors affect vegetation restoration in the simulation of Changting high-temperature environment,screened and verified the main environmental factors affect vegetation restoration in Changting red intensity soil erosion area,and to provide scientific basis for the mechanism of vegetation restoration in Changting red intensity soil erosion area and to provide the corresponding control strategy.Our results indicated that:(1)With the degradation of vegetation succession,the vegetation types and amount of each vegetation type were gradually reduced,forest structure simplified,broad-leaved species declining or even disappear,the dominance of coniferous species are showing an upward trend;The number vegetation species and species diversity index process showed a decreasing trend with the vegetation degradation.With the restoration of vegetation succession,the vegetation types and amount of each vegetation type were gradually increased,dominance of coniferous species show a downward trend,broadleaf species increased.The number vegetation species and species diversity index process showed a increasing trend with the vegetation restoration.(2)With the degradation of vegetation,,soil pH value increased,soil organic matter,nitrogen,phosphorus and potassium content decreased.In the succession process of vegetation restoration,the soil physical and chemical properties trend opposite succession process.Principal Components analysis show that:the soil coarse particles,soil bulk density,soil capillary porosity,soil maximum water holding capacity,soil nutrient content,soil pH values were the main factors affecting soil eroded area of vegetation restoration.(3)In the succession process of vegetation degradation,daily temperature changes of the vegetation types showed a trend inverted "U" shaped,the temperature gradually rises after sunrise,usually occurs at higher values after noon,the temperature gradually decreased after sunset,the amplitude of daily temperature variation is large.The atmospheric relative humidity diurnal variation of the vegetation types showed dynamic trend "U" shaped,Opposite the temperature.The soil temperatures diurnal variation of different vegetation types in different soil layers are basically consistent,and the surface temperature change width is the most obvious,,Changes in the magnitude of the temperature leveled off with the increase of soil depth.Diurnal variation of different vegetation types in different soil moisture soil layers basically the same,but did not change significantly,With the increase of soil depth,soil moisture increase.In the succession process of vegetation restoration,soil temperature,soil moisture,air temperature,air humidity and vegetation degradation trend opposite succession process.Through the principal components analysis we can see that:soil temperature,soil moisture,air temperature are the main influencing factors of changting red soil erosion zone vegetation restoration.(4)With the increase of the proportion of>2mm soil particles,three plant seed germination rate in general showed a downward trend;1-2mm soil particles less impact on the increase of the proportion of three seed germination.With the increase of the proportion of<1mm soil particles,there are three seed germination certain fluctuations,showing an increasing trend in general.This shows that the different proportions of soil particle composition has some effect on the germination of plant seeds,seed germination and plant water plays an important role.With the increase of the proportion of>2mm soil particles,the soil surface temperature showed a rising trend;1-2mm soil particles soil surface temperature increases With the increase in the proportion of soil particles less proportional differences between the soil particles was not significant;<1mm soil surface temperature of soil particles are increased With the a proportion of a downward trend.This shows that the soil particles have a significant impact on the soil surface temperature,and>2mm of soil particle composition on the soil surface temperature maximum(5)Based on the above analysis we can see that:during the process of vegetation degradation and recovery,microclimate factors and soil factors,both have an important impact on vegetation succession process of Changting red intensity soil erosion area,especially the soil factors impact on the vegetation succession process more obvious.From the soil factors,the soil coarse particles,soil bulk density,soil capillary porosity,soil maximum water holding capacity,soil nutrient content,soil pH values were the main factors affecting soil eroded area of vegetation restoration;in the microclimate,soil temperature,soil moisture,air temperature are the main influencing factors of changting red soil erosion zone vegetation restoration. |
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