The Effects Of Different Ecological Restoration Modes On Surface Soil Water Retention And Anti-erodibility In Karst Peak-cluster Depression

The karst area in southwest China is a typical area with extremely fragile ecosystem.Ecological restoration project is an important way to curb the degradation trend of karst ecosystem and improve its ecological service function.Based on the surface soil analysis of the different ecological restoration model in karst peak-cluster depression,According to the three ecological restoration modes of artificial ecological restoration mode,vegetation natural restoration mode and conservation tillage pattern,the infiltration performance,water holding performance and anti-erosion performance of surface soil were studied,and the comprehensive water and soil conservation capability of different artificial ecological restoration measures was summarized.The artificial ecological restoration modes included sample sites as follows:Pasture Grass(PG);Corn(CO);Depleted Grassland(DG);Deciduous Fruiter(DF);Deciduous Arbor(DA);Evergreen Arbor(EA);Mixed Forest(MF);Closed Forestland(CF).The vegetation natural restoration mode included sample sites as follows:Cultivated Pasture(CP);Shrub Grassland(SG);Secondary Forest(SF);Native Forest(NF).The conservation tillage pattern included sample sites as follows:NT;T-6M;T-2M;T-1M.The main conclusions are as follows:1.Effects of different ecological restoration modes on soil infiltration rate.(1)The infiltration rates were the fastest in the two mildly rocky desertification sites,the closed forest and the degraded grassland.The saturated infiltration rate of the degraded grassland was321.1mm/h,which was 16 times higher than that of the pasture grass.Artificial forest can improve soil infiltration rate.The surface soil infiltration rate of different artificial ecological restoration modes is mainly affected by porosity,bulk density,organic matter.(2)The infiltration rate of the surface soil saturated infiltration rate of the vegetation natural recovery modes is:NF>SF>SG>CP.The infiltration rate of natural recovery model is mainly affected by factors such as bulk density and soil texture.(3)There was a significant linear correlation between the saturation infiltration rate and the tillage frequency of the disturbance measures for different tillage frequencies of karst peak-cluster depression(R~2=0.858).With the increase of tillage times,the infiltration rate increased with the increase of tillage times.2.Effects of different ecological restoration modes on soil water retention:(1)In artificial ecological restoration samples,the soil saturated water content was the highest in the two mildly rocky desertification sites,but the rate of water withdrawal was also the fastest.The water holding capacity of MF is better than that of EA and DA.Artificial forest water-holding performance is better than PG and CO,reclaiming slope to reduce the water-holding capacity of the soil.(2)During the natural succession of karst peak-cluster depression,the soil water holding capacity is gradually enhanced.The maximum available storage capacity of various lands was sorted by size as follows:NF(60.2mm)>SG(58.9mm)>SF(56.6mm)>CP(53.8mm).(3)Frequent tillage activities will loosen the pore structure of surface soil and lead to serious water loss.The maximum effective storage capacity was positively correlated with bulk density and negatively correlated with tillage times.3.Effects of different ecological restoration modes on soil anti-erodibility:(1)The artificial vegetation restoration modes in karst peak-cluster depression can improve the soil anti-erodibility and improve the soil quality.Among the different artificial ecological restoration measures,MF,EA,DA and DF,the surface soil of the four artificial woodlands is more resistant to erosion than that of PG,DG and CO.(2)The comprehensive score of surface soil anti-erodibility of natural vegetation restoration model was as follows:CP>SF>NF>SG.(3)The surface soil erosion resistance was inversely proportional to the number of tillage,and the higher the tillage frequency,the worse the surface soil erosion resistance.4.Comprehensive analysis of soil and water conservation functions of different ecological restoration modes:(1)Returning farmland to forest and vegetation restoration are effective means to control water loss and improve soil storage capacity in karst areas.the comprehensive score of soil and water conservation of artificial ecological restoration modes was as follows:MF>CF>DF>EA>DA>PG>DP>CO.(2)In the natural restoration model of karst vegetation,the comprehensive score of soil and water conservation function was as follows:CP>NF>SF>SG.(3)The comprehensive score of soil and water conservation function of conservation tillage pattern was as follows:NT>T-6M>T-2M>T-1M.