Soil Biological Characteristics Of Different Land-use Type In The Southeastern Mu Us Sandy Land

In order to investigate soil biological characteristics for different land-use type in thesoutheastern Mu Us sandy land, in this paper, eight kinds of forest land (Pinus sytvestris var.mongolica, Populus bolleana, Platycladus orientalis, Pinus tabuliformis, Ulmus pumila,Cerasus tomentosa, Caragana korshinskii, Sabina vulgaris), three kinds ofgrassland(Heteropappusaltaicum, Stipa capillata, Agropyron cristatum) and three kinds offarmland(Zea mays, Triticum aestivum, Helianthus annuus) have been chosen as reseatchsubjects, and shifting sand dunes as a control. The number of soil bacteria, actinomycetes andfungi, soil sucrase, urease, catalase and alkaline phosphatase activity in0~20cm and20~40cm soil layers in different land-use types were measured. The purpose of this study was toinvestigate the distribution rule of soil biological characteristics for different land-use type insandland, analysed the relationship of soil microbial quantity, enzyme activities and organicmatters, and preliminary evaluation of the soil ecological fertility for different land-use typeswill be studied by using the principle components analysis. Accordingly, the research resultsin this paper can provide a certain theoretical instrument for the ecological restoration andland rational use of Mu Us sandy land. Main research conclusions are as follows:1. Compared with the drift sand, soil microbial quantity and enzyme activities hadsignificantly increased in woodlands in study area. The distribution of soil microbial numberand enzyme activities had an obvious hierarchical structure, that the surface was higher thanthe lower. Soil microbial quantity was bacteria(10~5)＞actinomycetes(10~4)＞fungi(10~2).Among the whole soil profile, the highest number of bacteria was in P. orientalis soil, thehighest number of actinomycetes and fungi was P. bolleana. Soil enzyme activities in P.bolleana were the highest during different forest land. Soil actinomycetes number, sucraseactivity and alkaline phosphatase activity in arbor forest were higher than in the shrubbery.There has a great improvement for soil quality in brosd-liaved forest compared to theconiferous forest when forest age was the same. In the0~20cm soil layer, soil microbialquantity of C. korshinskii with nitrogen-fixing function was hither than that of the othershrubberies. Recommendations will be geven priority to nitrogen fixing plants when selectingsand-fixation shrubs. 2. Compared with the drift sand, soil microbial quantity and enzyme activities hadincreased to varying degrees in grasslands in study area, but urease activity did not by much.Soil microbial number and enzyme activities have signigicantly decreased with depth in thevertial direction, except for urease. The number of soil microbial bacteria(10~5)＞actinomycetes(10~4)＞fungi(10~2). Throughout the whole soil profile, the number of soilbacteria and actinomycetes were the highest in S. capillata land, and fungi quantity was themost in A. cristatum land. In the0~40cm soil layer, soil sucrase, urease, catalase and alkalinephosphatase activity in different grasslands have showed that A. cristatum＞S. capillata.＞H.altaicum.3. Soil miacobial number and enzyme activities have significantly increased in farmlandsin study area compared with the drift sand. Soil microbial number and enzyme activities hadsignigicantly decreased with depth in the vertial direction, and significantly different betweenthe upper and lower soil. Soil microbial quantity was bacteria(10~6)＞actinomycetes(10~4)＞fungi(10~2), and the number of bacteia in farmland soil was higher than that in the forestlandand grassland. In the whole soil profile, T. aestivum soil had the largest number of soilbacteria and actinomycetes, and the fungi quantity of Z. mays soil was the largest amongfarmlands in study region. The maximum soil sucrase activity was in T. aestivum soil, soilurease, catalase and alkaline phosphatase activity were highest in Z. mays.4. Soil organic matter content was significantly positive correlated(P<0.05) to soilurease activity and was extremely significant positive correlated(P<0.01) to sucrase, catalaseand alkaline phosphatase activity in woodland. Soil bacterial quantity was signigicantlypositive correlated to alkaline phosphatase activity. The number of soil actinomycetes had asignificant positive correlation with surase and catalase activity, and was extremely significantpositive correlated to alkaline phosphatase activity. Soil fungi number was very significantpositive correlated to surease and alkaline phosphatase activity. In grassland, soil sucrase,urease, catalase and alkaline phosphatase activity were significant or extremely significantpositive correlated to organic matter content, which of them increased with organic mattercontent increased. There were highly correlated between soil enzyme activities and bacterialquantity, the correlation coefficient was0.64to0.80, followed by actinomucetes, in the rangeof0.50to0.68, fungi was the worst, in the range of0.13to0.46, and the correlation was notdistinct. In agriculture soils, organic matter content, enzyme activities and microbial quantityindicators showed a signigicant or extremely signigicant positive correlation, and all thecorrelation coefficients were greater than0.8. There were significantly positive correlationsfor soil bacteria number, actinomycetes and sucrase in farmland. Soil actinomycetes numberwas significantly positive correlated to sucrase and alkaline phosphatase activity. The number of soil fungi was significantly positive correlated to sucrase, urease, catalase and alkalinephosphatase activity.5. The synthesis principal component value of soil biological characteristics of woodlandwas as followed: P. bolleana(2.59)＞P. tabuliformis(0.65)＞P. orientalis(0.38)＞U.pumila(0.37)＞P. sytvestris(-0.33)＞C. korshinskii(-1.09)＞S. vulgaris(-1.16)＞C.tomentosa(-1.42), The synthesis principal component value of soil biological characteristicsof grassland was as followed: S. capillata(3.49)＞A. cristatum(-0.84)＞H. altaicum(-2.95).The synthesis principal component value of soil biological characteristics of farmland was asfollowed: Z. mays(1.23)＞T. aestivum(0.39)＞H. annuus(-1.61). P. bolleana and P.tabuliformis have a highest soil biological fertility on forest land in the southeast of Mu Ussandy land, the same to S. capillata on grassland, and Z. mays. have the best biologicalfertility on farmland.