| The planting area of Eucalyptus in China is expanding rapidly.As the main producing area of Eucalyptus in Guangxi,the planting area has reached 200,000 hectares.At present,mountain-making is widely used in planting Eucalyptus in Guangxi,which will lead to a series of problems,such as soil erosion and land degradation.The problem of soil nutrient imbalance is aggravated by the selective absorption of nutrients by tree species.The management mode of no-smelting mountain is considered to be an effective measure to replace slash-and-burn cultivation for plantation land because of its less damage to soil structure and ecological environment.However,the cost of non-smelting management measures is high,and the survival rate of seedlings is low in the initial stage,so it can not completely replace the smelting management mode.In this paper,the young Eucalyptus urophylla Plantation in Daguishan Forest Farm,Hezhou,Guangxi was studied for one year.Five physical properties,13 chemical properties and 4 biological properties of soil were determined.Data were analyzed by variance analysis,data envelopment model and Pearson correlation analysis.The main research results are as follows:(1)Different treatments significantly affected soil physical,chemical and biological properties of Eucalyptus plantation in a short time,and changed the ecological environment of plantation to a certain extent.The physical properties of soil surface layer(0-20cm)under the treatment of refining and non-Refining were significantly different.The soil bulk density was significantly reduced and the soil aeration was significantly increased by the treatment of refining.The soil bulk density was significantly reduced and the total porosity was significantly increased by the treatment of non-refining.In the soil(20-40 cm),the soil bulk density,soil capillary porosity and soil non-capillary porosity were significantly reduced by the treatment of refining.Under no-refining treatment,soil non-capillary porosity,total porosity and soil aeration increased significantly.Under different treatments,the physical properties of deep soil(40-60 cm,60-100 cm)did not change significantly.(2)Compared with the control group,the contents of pH,organic matter,total nitrogen,total potassium,available phosphorus,available potassiun,available calcium,available magnesium,available manganese and available zinc in the surface soil(0-20cm,20-40cm)were significantly increased in the initial stage of mountain-smelting treatment.The contents of total nitrogen,available potassium,available calcium,available magnesium,effective manganese,effective copper and effective zinc were significantly increased by no-refining treatment.The contents of total nitrogen,available calcium,available magnesium,available iron,available manganese,available copper and available zinc in deep soil(40-60 cm)were significantly higher than those in control group.In 60-100cm,the change of soil chemical properties was not obvious under different treatments.The change of soil chemical properties in different seasons:the contents of organic matter,total nitrogen,total potassium,available phosphorus,available potassium,available calcium,available magnesium,available manganese,available iron and available zinc increased significantly in the early stage of mountain-smelting treatment(spring and summer),and decreased significantly with the passage of time.The contents of total phosphorus,total potassium,available calcium,available magnesium,available iron,available manganese,available copper and available zinc were higher in summer and autumn under no-refining treatment.(3)soil urease,acid phosphatase,gluconase and dehydrogenase activities were significantly increased in the early stage of mountain refining(spring),and decreased in varying degrees with seasonal changes.The activities of soil urease,acid phosphatase,gluconase and dehydrogenase in the early stage of no-refining treatment(spring)were significantly higher than those in the control group,and the activities of soil urease,acid phosphatase,gluconase and dehydrogenase continued to increase in summer and autumn,but decreased in winter.(4)Both refining and non-Refining treatments can improve soil nutrient elements in varying degrees.Data Envelopment Model(DEM)was used to combine soil nutrient elements with plant growth factors to calculate the four-season growth response coefficients of Eucalyptus urophylla under three treatments:the highest growth response coefficient in spring was 1.17 of refining treatment;the growth response coefficients in summer,autumn and winter were all 1.17 of refining treatment.No-smelting treatment was the highest,which was 0.95,0.97 and 1.00,respectively.The purpose of this study is to find the most reasonable management mode by comparing the four-season variation of soil physical,chemical and biological properties and the response of plant growth factors to the four-season variation of soil nutrient elements in one year after refining and non-Refining treatment,and to provide scientific guidance for the management mode and fertilization mode of Eucalyptus urophylla Plantation land. |
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