Soil Fertility Quality Responses And Evolvement Mechanism In The Process Of Vegetation Restoration In Loess Hilly-Gully Area

Soil quality restoration and soil manage is the key factor for vegetation constructionand eco-environment sustainable development in Loess Plateau. Aimed at the requirement ofeco-environment construction and the hotspot in soil and ecology sciences in the LoessPlateau, taking on the soil fertilities quality to different rehabilitation ways, different ages anddifferent succession stages of vegetation as research objects in hilly loess plateau, soil fertilityresponses and evolvement in the process of vegetation restoration was studied in this project.Simple correlation, canonical correlation analysis and Path coefficient analysis were used toanalyses the relationship between the enzyme activities and soil fertility factors, the aggregatesand their affluences factors. The system of soil quality evaluation and the vegetation coveragetype which effectively improve soil quality preliminary was established. The goal was toprovide scientific reference for vegetation rehabilitation and soil quality care in the hilly LoessPlateau, and enrich the theory and method for soil quality management. The results obtainedwere summarized as follows:1. Soil genetic stages in researching area are in the process of taking off the salt,which is fertility accumulation, carbonate leaching and accumulating, weak mineralweathering. The typical soil has the whole profile characteristics. Soil structure, color andgenetic horizon are obviously difference in horizon. Soil nutrients accumulated are high inYunwu mountain, but in Shanghuang is low. Carbonate leached obviously and accumulated indeeper layer than claying horizon. The soil mechanical composition showed as sand contentwas higher than the content of silt and clay. Soil mineral element showed asSiO2>>Al2O3>CaO>Fe2O3>K2O≈MgO>TiO2>MnO2。Soil development is in the stage ofphysical weathering and chemical weathering is weak, mineral elements movement is notobviously.2. The evolvement rule of soil chemical, physical, biological indicators and soilcomprehensive quality index were clarified with different vegetation recovering ways.Soil organic matter, total nitrogen, available nitrogen, CEC are shown as bush forest land>natural meadow> artificial meadow>orchard>farmland, but the available P and available Kare different influenced by fertilizing. The density of soil was shown as:orchard>farmland>natural meadow>artificial meadow>bush forest land in the surface layer.Ⅱ Soil fertility Quality Responses and Evolvement Mechanism in the Process of Vegetation Restoration in loess hilly-gully AreaSoil total aggregate was shown as: natural meadow > bush forest land > orchard > farmland>artificial meadow. To different lands usage types, bush forest land and natural meadow hadpromote function to the development of larger particle diameter aggregate, but farmland ,orchard and artificial meadow had the function to the smaller ones. Soil microaggregate wasshown as higher content of 1-0.01mm tiny aggregate in bush forest land, artificial meadowand natural meadow, but orchard was lower comparatively. There were distinct differencesin soil biology enzyme activities. Natural meadow had the highest enzyme activity, than bushforest land and artificial meadow, orchard and farmland were lower. For bush forest land, itwas higher enzyme activity in longer planted year than shorter, but orchard was noremarkable differences.3. Soil fertility quality evolvement shown that it is consistent with vegetationsuccession, that is, in high vegetation stage, the soil chemical, physical and biologicalfertility are also high. Reclamation can reduce the soil quality obviously, but the slightlygrazing can enhance soil chemical and biological quality and recede soil physical quality.SOM, total N, total P, available N, Available K and four soil urease, sucrase, neutralphosphatase and catalase are all shown as Stipa gradiss.Community >Artemisia sacrorumLedeb community> Stipa bungana Trin Community > Thymus mongolicus Ronn community.The co...