| In the loess area of Western Shanxi,there are various types of topograp Hy and geomorp Hology,but the problem of soil erosion is more serious.So far,there are a lot of research results on the artificial forest in the loess area of Western Shanxi,but these studies are mainly aimed at the plantation of a certain life environment and a certain tree species,but there are few comprehensive studies on different tree species,different habitats and different forest ages on the artificial forest in the loess area of Western Shanxi.The evaluation of soil fertility quality in this area can provide a theoretical basis for the sustainable utilization of soil and the rational management and allocation of plantation in loess area.In order to provide a theoretical basis for the rational management and allocation of Pinus tabulaeformis plantation,the sustainable management of soil and the restoration of soil fertility in the middle of Shanxi Province(20a,25 A,32a,40 a,45A)Pinus tabulaeformis plantation as the research object,15 sample plots were set up to investigate the soil,vegetation,topograp Hy and geomorp Hology of the study area,determine and analyze the p Hysical and chemical properties of the soil,and analyze the change rule between different age stages and different soil depth(0-10 cm,10-20 cm,20-30 cm,30-50 cm,50-100cm).The least data set was selected by principal component analysis,and the system of evaluating soil fertility quality of Pinus tabulaeformis Plantation of different ages was established.The main conclusions are as follows:(1)Analysis of soil p Hysical indexes of Pinus tabulaeformis Plantation in different forest ages: there were significant differences in soil bulk density and non capillary porosity of Pinus tabulaeformis Plantation in different forest ages(P < 0.05),soil moisture content in 30-50 cm soil layer(P < 0.05),capillary water capacity in 50-100 cm soil layer(P < 0.05),capillary porosity in 0-10 cm soil layer(P < 0.05)(P<0.05).However,there was no significant difference in other p Hysical indexes(maximum water holding capacity,total porosity,capillary porosity)among different ages of Pinus tabulaeformis Plantation Soils(P > 0.05).Soil bulk density increased first and then decreased with the deepening of soil depth,soil moisture content decreased first and then increased,and the maximum water holding capacity,capillary water holding capacity,total porosity,capillary porosity soil depth was not significant Break down.(2)Analysis of soil chemical indexes of Pinus tabulaeformis Plantation in different forest ages: there were significant differences in organic matter content and total p Hosp Horus content in soil of Pinus tabulaeformis Plantation in different forest ages(P < 0.01);there were significant differences in soil p H value in 10-20 cm soil layer(P < 0.05);there were significant differences in soil p H value in 20-30 cm soil layer(P < 0.01);there were significant differences in total nitrogen content in 10-20 cm soil layer(P < 0.05))There was significant difference in other soil layers(P < 0.01).With the deepening of soil depth,the p H value of soil becomes more alkaline,and the organic matter,total nitrogen and total p Hosp Horus of soil decrease gradually.(3)The correlation analysis of 11 indexes of soil p Hysical and chemical properties shows that: The correlation between capillary water holding capacity and capillary porosity is the strongest,the coefficient is 0.975.Based on the establishment of the minimum data set(MDS)for soil fertility quality evaluation of Pinus tabulaeformis Plantation of different forest ages,six representative indexes were selected: soil bulk density,maximum water holding capacity,total porosity,non capillary porosity,soil p H value and organic matter content.(4)Among the three evaluation methods of soil fertility quality,the conclusion of soil comprehensive index method and fuzzy comprehensive evaluation method is that soil fertility gradually increases with the increase of forest age,while the conclusion of DEA model method is that soil fertility first increases and then decreases with the increase of forest age.It may be that both the weighted average method and the fuzzy comprehensive evaluation method process the data according to the correlation,while the DEA model inputs the index directly into the model to get the score of soil fertility quality. |
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