Studies On The Base Fetrilizer Utilization Rate And Nutrient Demand Of Eucalypt

Fertilizer utilization rate was low in the agriculture and forestry for long time,relatedresearches were less in forestry than that in agriculture.In this study, plants,soil and fertilizerwere studied in order to find the primary effect factors in Eucalypt fertilizer utilization.(1)In this study, the method of leaching and extracting were used to research the N P Kreleasing characteristics and their sustained-release properties of the bulk fertilizer and thegranular fertilizer which were made by the same raw materials.The kinetic equation, Parabolicdiffusion equation and Elovich equation were used to fit the element releasing processes.Theresults show the kinetic equation was the best one for matching the bulk fertilizer,the degree offitting is more than0.95, and the Elovich equation was more suitable for matching the granularfertilizer. Meanwhile, the realeasing concentration of P in the extract was compared,theoutcome was that the fertilizers with different shape and quality were different, the bulkfertilizer and the granular fertilizer in control group were significantly different.In addition,the fitted equation of P was used to calculate the releasing rate of different fertilizer in the1thand28th day, the results were matched with the national sustained-release degree standard forall trial fertilizers, The non-porous bulk fertilizer's dissolution rate reduced by46.02%and6.30%in the1th and28th day comparing granular fertilizer,the porous bulk fertilizer was36.92%and10.92%,Sustained-release effect was notable.Finally VI fertilizer was selected asthe best one of all trial controlled-release fertilizers after testing in the field.(2)Bulk Fertilizer and granular fertilizer were used in this pot experiment, which weremade by the same material.The result was the two kinds of bulk fertilizer own greater staminathan the granular fertilizer.The differences of the treatments were not significant in the firstthree months, After three months, the difference begin appear.When the investigation wascomplete, comparing the seedlings with the granular fertilizer,the height of the ones with theBulk Fertilizer increased by10.6%and4.3%and the ground diameter increased by8.8%and2%.In6th month the utilization efficiency of the bulk fertilizer with pore improved by20% than granular fertilizer and of the bulk fertilizer without pore was equal to the granularfertilizer in Nitrogen.The utilization efficiency of two kind of bulk fertilizer improved by21.57%and19.23%than the granular in phosphorous,improved by16.2%and11.5%thangranular fertlizer in potassium.In the9th month The utilization efficiency of two kind of bulkfertilizer improved by43.18%and13.64%,20.42%and11.5%,41.71%and31.11%respectively than granular fertilizer respectively in Nitrogen,phosphorous and potassium.Theaverage utilization efficiency of N P K in the Bulk Fertilizer was not less than that in thegranular fertilizer. Indicating that bulk fertilizer was helpful to improve the efficiency offertilizer and it was more suitable for seedlings' demand.(3)DH_32-29clone Eucalypt seedlings were used in this study to find the law of nutrientrequirement.The results show the law can be fitted well by logistic curve,the time thatfertilizer demand rise sharply was the inflection point.The inflection point of growth appearedin the3th month and the demand proportion of N P K was46.93%,40.88%and42.42%duringthe observation time.The seedling's of the N P K was3394.91mg,1069.56mg and3605.13mg,the requirement ratio of N:P₂O₅:K₂O should be controlled at about1:0.5:1.5.(4)The usage efficiency of feitilizer nutrients also could be affected by the N P Kratio.Three kinds of ratio which were6:12:6,7:11:7,16:16:16were used in this experiment.Allof them own the same total nutrient.The utilization of them was35.23%,17.83%,22.49%inNitrogen and15.4%,16.59%,12.83%in phosphorous and51.19%,23.1%,25.82%inpotassium.The result shows the seedling grow best by using the ratio6:12:6,the nutrientutilization efficiency was the highest.(5)The usage efficiency of nutrients can be affected directly by the the amount offeitilizer.There were3levels amount of feitilizer in this experiment:250g,500g,750g.Thenutrient utilization efficiency of750g'N P K was7.15%,3.33%,and7.84%,but the nutrientutilization efficiency of250g was37.32%,15.4%and50.31%.(6)Preservation capacity of the soil 'N P K in South china nersury and Hetou wasmeasured by leaching the soil with feitilizer.The results of leaching could be fitted well. Thesoil preservation capacity could be got by the fitting equation,they were95.75mg/kg,40.50 mg/kg,105.7mg/kg in soil of South china nersury and92.38mg/kg,39.43mg/kg,90.50mg/kgin soil of Hetou.The soil can provide N P K by94.89kg/hm²,14.95kg/hm²,134.06kg/hm²inSouth china nersury and57.31kg/hm²,29.9kg/hm²,89.63kg/hm²in Hetou.(7)Fertility subtraction,balanced fertilization and correction factor method of the soiltesting and fertilizer recommendation were used to calculate the nurtrition requirement in orderto get the target yield which was60000kg/hm²in stalk.According to fertility subtraction,therequirement of N P K was342kg/hm²,73.8kg/hm²,282kg/hm², according to balancedfertilization, the requirement of N P K was316.76kg/hm²,72.53kg/hm²,278.98kg/hm²,according to correction factor method, the requirement of N P K was247.21kg/hm²,59.85kg/hm²,169.82kg/hm².