Study On The Natural Restoration Vegetation Characters And The Vegetation Restoration Mode Construction In Sloping-land With Purple Soils In Hengyang

By systemically studying the natural restoration vegetation characters and the vegetation restoration mode construction in Sloping-land with Purple Soils in Hengyang, the results showed that:(1) Classification of plant community in Sloping-land with Purple Soils in Hengyang was conducted by fuzzy classification analysis, and species diversity of different spaces were analyzed by richness index(R), Simpson index (D), Shannon-Wiener index (H) and Pielous evenness index (E).The results showed that:1) the plant communities in the purple soil slope of Hengyang could be divided into six types:Ⅰ.Ass. Cuninghamia lanceolata—Vitex negundo var.cannabifolia+Serissa foetida—Prunella vulgaris.;Ⅱ. Ass. Pinus massoniana—Vitex negundo var.cannabifolia+Serissa foetida—Chrysanthemum indicum;Ⅲ. Ass.Agrimonia pilosa—Chrysanthemum indicum+Taraxacum mongolicum;Ⅳ. Ass. Abelia chinensis—Chrysanthemum indicum+Taraxacum mongolicum;Ⅴ. Ass. Miscanthus sinensis+Setaria viridis;Ⅵ. Ass. Miscanthus sinensis+Verbena officinalis.These six plant communities were distributed in different spaces.2)The species diversities in Sloping-land with purple soils in Hengyang were analyzed and the results showed that:①The sequence of richness index, evenness indexand diversity index from high to low was as follows:herb layer> shrub layer> tree layer.②here were certain characters of sloping-land with Purple Soils in Hengyang, richness index(R),Simpson index(D),Shannon-Wiener index(H) and Pielous evenness index(E) of tree layer, shrub layer and herb layer were higher in north-facing slope than those of the corresponding level places in south-facing slope;③Bio-diversity indices were different in perpendicular space in sloping-land with Purple Soils in Hengyang. Richness index(R), Simpson index (D), Shannon-Wiener index (H) and Pielous evenness index (E) were of a trend to increase from the upper-slope to the lower-slope, It showed that the plant catorgories and modes were different in different places in Sloping-land with purple soils in Hengyang.(2) The biomass properties of the plant communities on the purple soil slope in Hengyang was studied.The results are as follows:1)In south-facing slope,the total biomass of the plant communities on the purple soil slope in Hengyang was 5133.6kg.hm-2,The biomass of the tree layer,the shrub layer,the herbage layer and the deadwood and defoliation layer were 1936.7kg.hm-2,1624.7kg.hm"2,1400.8kg.hm-2and 171.4kg.hm-2,they each account for 20.9%,24.1%,50.6% and 4.4% of the total biomass of the plant commumities; In north-facing slope,the total biomass of the plant communities on the purple soil slope in Hengyang was 5512.4kg.hm'2,The biomass of the tree layer,the shrub layer,the herbage layer and the deadwood and defoliation layer were 2251.4.7kg.hm-2,1650.6kg.hm-2,1437.2kg. hm-2and 173.2kg.hm-2,they each account for 22.0%,23.4%,50.3% and 4.3% of the total biomass of the plant commumities; 2)In south-facing slope,the percentage of the above-ground biomass and the root biomass in the tree layer,the shrub layer,the herbage layer each was 80.2%,19.8%; 52.4%,47.6% and 43.6%,56.4%; in north-facing slope,the percentage of the above-ground biomass and the root biomass in the tree layer,the shrub layer,the herbage layer each was 83.2%,16.8%; 55.0%,45.0%,46.6%and 53.4%; 3) The biomass of the tree layer,the shrub layer and the herbage layer on the purple soil slope in Hengyang were different:the tree layer only exists in the down-slope;the sequence of the biomass of the shrub layer is:the middle-slope> the down-slope; the sequence of the biomass of the herbage layer and the deadwood and defoliation are all:the middle-slope> the down-slope>the-upper slope; 4)The percentage of the biomass of the branches and the leaves,the deadwood and defoliation and the root in the total biomass are.in the upper-slope and the middle-slope, the sequence is:the roots>the branches and leaves> the deadwood and defoliation,but in the down-slope,the sequence is:the branches and the leaves> the roots> the deadwood and the defoliation; (5)The ratio between the percentage of the above-ground biomass and the root biomass in the herbage layer total biomass gradually increase from the upper-slope to the down-slope on the purple soil slope in Hengyang.(3) This study makes a survey from the perspective of community studies.It is conducted in the shrub stage community of natural vegetation recovery process at Sloping-land with Purple Soils in Hengyang,where 1hm2 plot with 400 contiguous quadrats(5m×5m) was designed. The spatial pattern of main populations of natural recovery shrub stage community were measured with the help of 6 indexes,such as clump index,index of mean crowing,index of patching,Green's index,the clumping intensity index,Cassie's index and variance/mean ratio method as well as.All the spatial pattern of the main populations of the shrub community was clumpy.The results revealed that the distribution of the populations was influenced mainly by their biological and ecological characteristics.In addition,competition among the species would affect the distribution pattern of the populations.With the progress of restoration,the clumping intensity would decrease,so it could be used as an indicator for plant community restoration in some degree.(4) The niche dynamics in natural restoration succession process in Sloping-land with Purple Soils in Hengyang were studied by the quantitative analysis method. First,by using the space series to replace time courses,four typical sample plots standing for four different successive stages were chosen.then the niche breadths and the niche overlaps were measured using the formula described by Levins and Pianka,and further analyzed their ecological sense. The results showed that:1) The species with the largest niche breaths have stronger capacity to adapt to environment and higher efficiency to utilize resources;2)The dynamics of niche properly manifested the dynamics of environment,competition relationship and distribution pattern;3)The niche overlaps were higher between the species that had greater niche breadths and these species that had more similar ecological characteristics;4)The average niche overlaps increased from succession stageⅠto succession stageⅢ, and reached tiptop in successionⅢ,and then decreased little in successionⅣ.(5) The soil of 0～50cm on the purple soil slope in Hengyang was studied. The results showed that:l)In the same level space,as to the water content in soil,the result was:the north-facing slope>the south-facing slope, but there was a contrary tendency in coefficient of variance in soil water;2) In the same perpendicular space, as to the water content in soil,the result was:the lower-slope> the middle-slope> the upper-slope.As to the coefficient of variance in soil water on the south-facing slope,the result was:the upper-slope>the middle-slope>the lower-slope,but there a contrary tendency in the coefficient of variance in soil water on the north-facing slope; 3) In the same level space,with the increasing in the depth in soil,there was a increasing tendency in the water content.As to the coefficient of variance in soil wate,it present a regulation of "V"curve, with the increasing in the depth in soil there was a decreasing tendency first then there was a increasing tendency both on the south-facing slope and the north-facing slope,in the depth of 10-30cm,the water content in soil is the stablest.(6) By summarizing the achievements of previous studies and collecting experimental data from Ecological Experimental Station of Purple Soil of Ecological Research Institute of Hunan Agriculture University,this paper put forword three typical models to vegetation restoration in Sloping-land with Purple Soils in Hengyang from aspects of overall situation,urgency,efficiency,hierarchy, sustainabi-lity, innovation and diversity.These three models:shrub-grass mode,arbor-shrub-grass mode,and fruit bushes-green manure crops in upper slope,middle slope and down slope respectively,are expected promote the all-round,continually and harmonious development of ecology,ecomical and society.