Effects Of Vegetation Restoration On Soil Physical Properties Of Sandy Land In Poyang Lake

The aim of the study was to explore the influence of vegetation restoration on soil physical properties of sandy land in Poyang Lake and provide theoretical basis for further optimizing vegetation type allocation of sandy land in Poyang Lake.Soil samples of dominant species such as Pinus elliottii,Vetiveria zizanioides,Cynodon dactylon(Linn.)Pers.,Vitex rotundifoli,Glochidion puberum L and bare land were collected in the typical desertification area of Poyang Lake in Jiangxi Province,and soil bulk density,soil water content,total soil porosity,capillary porosity,non-capillary porosity,soil aeration,soil capillary water holding capacity,saturated water content and other physical properties were determined.The indicators,by means of coefficient of variation CV,analysis of variance,correlation analysis and other methods to study the impact of vegetation coverage on soil physical properties and the differences in soil physical indicators between vegetation coverage area and bare soil.The results show the physical properties of soil are different in both horizontal and vertical profiles.1.In the horizontal direction,compared with bare land,the soil physical properties of the vegetation cover area are improved,the bulk density is small,total porosity,capillary porosity,non-capillary porosity,soil aeration,capillary water holding capacity and saturated water content are large.The specific performance is as follows:(1)Soil bulk density is represented by G.puberum L < P.elliottii < C.dactylon < V.rotundifoli = V.zizanioides < bare land;(2)Except for P.elliottii,soil water content in other vegetation plots is greater than that of bare land;(3)Total porosity is represented by G.puberum L > P.elliottii > C.dactylon > V.zizanioides = V.rotundifoli > bare land;(4)Except for P.elliottii and G.puberum L,soil capillary porosity in other vegetation plots is greater than that of bare land;(5)Except for V.rotundifoli,soil non-capillary porosity in other vegetation plots is greater than that of bare soil;(6)Except V.zizanioides,soil aeration of other vegetation plots is greater than that of bare soil;(7)Except for P.elliottii and G.puberum L,soil capillary water holding capacity in other vegetation plots is larger than that of bare land;(8)The saturated water content of soil is represented by G.puberum L > P.elliottii > C.dactylon > V.rotundifoli > V.zizanioides > bare land.2.Along the vertical section,the soil physical properties of different regions show the following changes with the depth of the soil layer:(1)The soil bulk density of soil layer A is less than that of soil layer B and C;(2)The soil water content increases first and then decreases,and the maximum appeared in the soil layer B;(3)The total soil porosity gradually decreases with the increase of soil depth;(4)Soil capillary porosity increases first and then decreases with the increase of soil depth.Except for C.dactylon and G.puberum L plots,the soil capillary porosity of soil layer A is less than that of soil layer C;(5)The non-capillary porosity decreases first and then increases with the increase of soil depth.Except for C.dactylon and G.puberum L plots,the non-capillary porosity of soil layer A is larger than that of soil layer C;(6)The soil aeration decreases first and then increases with the increase of soil depth,and except for V.zizanioides N plot,the soil aeration of soil layer A is greater than that of soil layer C;(7)The water holding capacity of soil capillary increases first and then decreases with the increase of soil depth;(8)Except for P.elliottii plot,V.zizanioides N plot and C.dactylon plot,soil saturated water content in bare land and other vegetation cover areas decreases with the increase of soil depth.3.One-way analysis of variance of soil physical indicators showed that soil water content,capillary water holding capacity in bare land and vegetation coverage areas were different,but the difference was not obvious;other physical indicators were significantly different(p <0.05).The study subjects were divided into two categories: exotic species and native species.One-way analysis of variance of physical indicators showed that soil water content in bare land,exotic species and native species coverage areas was different,but the difference was not obvious;other physical indicators were significantly different(p <0.05).The study subjects were divided into three categories: arbor,shrub and herb for one-way analysis of variance.The results showed that the soil capillary water holding capacity of arbor,shrubs and herbaceous plants was different,but the difference was not obvious;other physical indicators were significantly different(p <0.05).4.Pearson correlation analysis of soil physical indicators showed that there was a significant or extremely significant correlation between soil bulk density,soil water content,total porosity,capillary porosity,non-capillary porosity,soil aeration,and saturated water holding capacity.The capillary water holding capacity was significantly correlated with capillary porosity and non-capillary porosity,and no correlation with other indicators.The above results showed that vegetation restoration played a significant role in improving soil physical properties in the desertification area of Poyang Lake,which could provide data support for suggestions and measures for ecological restoration of sandy land in Poyang Lake.