Effects Of Different Fertilization Treatments On Soil Improvement Of Camellia Oleifera Forest In Purple Soil Water And Soil Erosion Area

Purple soil is one of the more special soil types in the hilly mountains of southern China,mainly distributed in the subtropical regions of China.The purple soil is rich in phosphorus,potassium a-nd mineral nutrients,but there are many unfavorable factors such a-s shallow soil layer,poor structure,low organic matter content,poo-r water retention and soil conservation capacity,and most plants ar-e poorly grown.In addition,due to long-term human disturbance,a large number of vegetation in the purple soil area suffered severe damage,the mother layer was bare,the soil nutrient leaching was more serious,and the vegetation restoration was difficult,which aff-ected the sustainable management of agroforestry in the purple soil-area.The restoration of forest ecosystems in the hilly areas of purpl-e soil areas and the maintenance of soil fertility have become maj or issues that forestry workers need to solve urgently.Camellia oleif-era is one of the economic forest trees with a large area planted in the purple soil area.The quality of tea oil in purple soil area is g-ood,but its yield is generally low,which affects the income of for-est farmers in purple soil area and the coordinated development of regional economy.In this thesis,the 25-year-old Camellia oleifera f-orest in purple soil area was used as the research object,and the c-ompletely randomized block experiment design was used to analyze different fertilization treatments(natural organic material organic fe-rtilizer,organic-inorganic compound fertilizer,livestock manure orga-nic fertilizer,NPK fertilizer,phosphoric acid).On the basis of cha-nges in soil physical and chemical properties on different slopes of Camellia oleifera forest after 1 year,further analysis of natural org-anic material organic fertilizer,organic-inorganic compound fertilizer,livestock manure organic fertilizer and other fertilization treatments on different slopes of Camellia oleifera forest The changes of soil enzyme activity,microbial functional diversity and microbial struct-ure diversity were evaluated.The effects of different fertilization tre-atments on the soil of Camellia oleifera forest were evaluated.The results of the study can theoretically reveal the physical and chemi-cal properties,enzymatic activity,microbial functional diversity and microbes of purple soil.Structural diversity and other responses to different fertilization treatments,and can provide a theoretical basis for nutrient management and soil fertility of Camellia oleifera fore-st in purple soil and water erosion area.The main findings are as f-ollows:(1)In terms of the difference in depth of different soil layer-s,the soil moisture content of the topsoil(0-20 cm)of the seven f-ertilization treatments was higher than that of the deep soil(20-40 cm)before and after fertilization,but the soil bulk densityw-as opposite.In terms of the difference between treatments,the natura-1 moisture content and bulk density of the soil under the seven tre-atments did not differ much before fertilization.After fertilization,t-he application of organic-inorganic compound fertilizer to improve the natural moisture content of soil on three slopes Preferably,the order followed by natural organic material organic fertilizer,livestoc-k manure organic fertilizer,NPK fertilizer,monoammonium phosph-ate,N fertilizer,the control soil does not fertilize the soil natural moisture content does not change much.The application of organic-inorganic compound fertilizer had the highest reduction rate of soil bulk density on the three slopes,followed by natural organic materi-al organic fertilizer,livestock manure organic fertilizer,NPK fertiliz-er,monoammonium phosphate and N fertilizer,and the control gro-up was not fertilized.The soil bulk density did not change much.(2)With the deepening of soil layer,the soil pH values of Camellia oleifera forests increased with the deepening of soil layers before and after 7 fertilization treatments,while the contents of tot-al carbon,total nitrogen,total phosphorus and total potassium decr-eased with the deepening of soil layers.The chemical properties of t-he soil under the seven treatments did not differ much before fertil-ization.In terms of pH and total potassium,the application of org-anic-inorganic compound fertilizer has the best improvement effect,followed by natural organic material organic fertilizer,livestock man-ure organic fertilizer,NPK fertilizer and phosphoric acid.Ammoniu-m,N fertilizer.For the whole carbon and total nitrogen,the applic-ation of N fertilizer has the best effect on the improvement of soil total carbon and total nitrogen,followed by organic and inorganic compound fertilizer,natural organic material organic fertilizer,livest-ock manure organic fertilizer,NPK fertilizer,Monoammonium phosp-hate.In terms of total phosphorus,the application of monoammoni-um phosphate has the best effect on the improvement of soil total phosphorus,followed by organic and inorganic compound fertilizer,natural organic material organic fertilizer,livestock manure organic f-ertilizer,NPK fertilizer and N fertilizer.There was no significant d-ifference in soil chemical properties before and after fertilization in the control group.(3)The urease,acid phosphatase,sucrase and cellulase activit-ies of soil showed an increasing trend with the decline of soil slo-pe before and after fertilization.The three fertilization treatments(nat-ural organic material organic fertilizer,organic-inorganic compound fertilizer,poultry manure organic fertilizer)have improved effects on the four enzyme activities of different slope soils.The order of im-provement effect is:organic-inorganic complex Mixed fertilizer>na-tural organic material organic fertilizer>livestock manure organic f-ertilizer>control group does not apply fertilizer.Soil urease,acid p-hosphatase,sucrase and cellulase activities were significantly correl-ated with soil total carbon and total nitrogen.Urease,acid phosphata-se and cellulase activities reached a very significant positive correl-ation with total carbon content;sucrase activity and total carbon co-ntent showed a significant positive correlation;urease,sucrase activi-ty and total nitrogen content reached significant The positive correl-ation level,acid phosphatase activity and total nitrogen content wer-e significantly positively correlated,cellulase activity and total nitro-gen content showed a significantly negative correlation level;ureas-e activity and total potassium content showed a significant positive correlation;invertase activity and The total phosphorus content show-ed a very significant positive correlation level;urease activity and pH showed a very significant positive correlation level.(4)The three kinds of fertilization treatments(natural organic material organic fertilizer,organic-inorganic compound fertilizer,po-ultry manure organic fertilizer)and the control group did not apply the different slope soils,the total activity of microorganisms AWC-D values were "S" type,and with The decline in the slope position is gradually increasing.After fertilization,at the 168h,the order of soil AWCD values from high to low is:organic-inorganic compoun d fertilizer>natural organic material organic fertilizer>livestock ma-nure organic fertilizer>control group.After fertilization,the trends of soil polymer,carbohydrate,phenolic acids,amino acids,amines a-nd carboxylic acids under the three treatments showed an upward t-rend.Correlation analysis showed that the Shonnon index was sign ificantly positively correlated with total carbon and total nitrogen(P<0.05).(5)After fertilization,the bacterial sequences identified by th-e three fertilization treatments(application of natural organic organi-c fertilizer,organic-inorganic compound fertilizer,livestock manure organic fertilizer)and the control group belonged to 45 gates,68 cl-asses,and 116 orders.202 families,252 genera,98 species.The se-quencing results of the bacteria gate showed that the dominant bact-eria were Proteobacteria,Acidobacteria,Planctomycetes,and Chloro-flexi.The identified fungal sequences belong to 9 gates,28 classes,72 orders,131 families,196 genera,and 161 species.The sequenci-ng results of the fungal gate showed that the dominant bacteria wer-e Ascomycota and Basidiomycota.Correlation analysis between soil bacterial community diversity and soil physical and chemical propert-ies under different fertilization treatments showed that in terms of physical and chemical properties,bacterial chao value was significan-tly negatively correlated with total potassium;ace value was signifi-cantly positively correlated with soil bulk density,coverages and n-atural water content.Positively correlated and negatively correlated with pH.Correlation analysis between soil fungal community diversi-ty and soil physical and chemical properties under different fertiliz-ation treatments showed that the fungal chao value and ace value r-eached significant levels with total potassium,and the chao value a-nd bulk density showed a significant negative correlation.