Study On Effects Of Vegetation Restoration On Soil Properties And Qualities In Heidaigou Mine Dump

In this paper, taking Heidaigou mine north dump as the research object and thenewly-constructed as the control group, we make a further research on soil physicaland chemical properties in different vegetation restoration types by fieldinvestigations and laboratory analysis. Meanwhile, we used principal componentanalysis method to analyze various soil quality and comprehensive evaluation. Theresults showed that different vegetation restoration types have different effects on soilproperties and can provide a scientific basis for the correct evaluation of effectsvegetation restoration and soil quality in the Loess Plateau. The main conclusions areas follows.(1)After vegetation restoration, the soil physical and chemical indicators of theHeidaigou north dump were improved compared to the control group. It indicate thesoil physical and chemical properties has been improved after restoration.(2) The effects of different vegetation allocation types on the properties of refusedump soil are various. The shrubs with strong drought resistance capability, waterretention and nitrogen-fixing capability has the best effect on improving the soilproperties, such as Hippophae rhamnoides、Caragana microphylla Lam. the bushesand tree take the second place. However, planting a single species tree exert littleeffect on improving soil characteristics.(3) Under different vegetation types, soil bulk density and pH showing theincreasing trend with increasing soil depth overall. Butthe porosity, moisture content,organic matter contain, available N, available P, available P showing the decreasingtrend with increasing soil depth and overall.On the other hand, part of the plots on thephysical and chemical properties of these factors did not exhibit decreasing orincreasing trend due to the activity of deeper roots of tree effects soil physical andchemical properties in different levels.(4) Soil bulk density is between1.29g/cm3~1.70g/cm3, Hippophae rhamnoideshas the minimum bulk density for1.35g/cm3on average; soil moisture content isbetween4.14%-13.96%, Pinus tabulaeformis+Hippophae rhamnoides+Caraganamicrophylla Lam is the maximum moisture content for13.32%. The results showed that planting Hippophae rhamnoides、Caragana microphylla Lam、Hippophaerhamnoides and Caragana microphylla Lam for shrubs bushes and Pinustabulaeformis mixed pattern in the region have better results.(5) Compared to the control group, soil pH value has improved under differentvegetation types and pH value increasing with the soil depth increasing. It indicatesthat the soil has alkalization trend in this region. Organic content is between2.49g/kg~15.41g/kg, available N content is between5.28mg/kg~38.77mg/kg, available Pcontent is between1.17mg/kg~10.55mg/kg, available K content is between17.48mg/kg~152.47mg/kg.Number2(Pinus tabulaeformis+Hippophae rhamnoides+Caragana microphylla Lam) has the maximum average available N content for21.32mg/kg; number7(Caragana microphylla Lam) has the maximum averageavailable P content for6.47mg/kg,;number2(Pinus tabulaeformis+Hippophaerhamnoides+Caragana microphylla Lam) has the maximum average available Kcontent for90.21mg/kg.It is showed that Hippophae rhamnoides、 Caraganamicrophylla Lam、 Pinus tabulaeformis and Hippophae rhamnoides, Caraganamicrophylla Lam trees shrubs mixed cropping patterns to improve soil available N,available P, available K content has a significant role in this area.(6) With the soil depth increasing,correlation between the physical andchemical properties and between the different chemical properties was not significantgradually, maybe due to the soil compaction increased with the soil depth and make adifficulty in activities of plants roots. Thus it caused the effects on soil improvementwas not obviously.(7)Analysis by SPSS software for various indicators of soil physical andchemical properties of each factor and principal component, get the following sort ofsoil quality assessment: number6(Hippophae rhamnoides)> number2(Pinustabulaeformis+Hippophae rhamnoides+Caragana microphylla Lam)> number7(Caragana microphylla Lam)> number1(Pinus tabulaeformis+Populus simonii+Salix babylonica)> number5(Medicago sativa)> number9(Hippophaerhamnoides+Prunus armeniaca+Medicago sativa)> number4(Pinus tabulaeformis)>number3(Populus simonii1998)> number8(Populus simonii2004)> number10.Hippophae rhamnoides has the highest soil comprehensive evaluation; Caraganamicrophylla Lam as well Caragana microphylla Lam and Hippophae rhamnoidesshrubs bushes and trees mixed pattern also has a good effect for the soil quality in thisregion. Therefore, planting Hippophae rhamnoides、Caragana microphylla Lam、 Hippophae rhamnoides and Caragana microphylla Lam for shrubs bushes and treesmixed pattern is suitable for this area.