Effects Of Fertilization On Soil Organic Carbon Mineralization And Soil Fertility Of Salix Babylonica Plantations

Salix babylonica is an ideal plant species of short rotation fast-growing timber. In recentyears, fertilization has become an important measure for Salix babylonica plantation productionand operation with the continued expansion of planting areas. However, there are many vitalproblems such as abusing of fertilizer, the waste of fertilizer and not fully absorbed it etc. Thatleads to the soil biological pulmonary circulation disorders including of the absorption of soilnutrient utilization and mineralization of soil organic matter, which seriously affect the soilfertility and carbon emission reduction. So that, using Lian yungang city shore Salix ’binliuplantation as the research object, with the measures of N,P,K fertilization treatments and the soilcultivation test in the lab, the experiment were set up in order to study on soil organic carbonmineralization and soil fertility conditions, meanwhile, evaluate soil fertility quality in themethod of principal component analysis. The purpose is that obtaining the plantation fertilizationtechnology and the important basis on enhancing the soil fertility and carbon emissionreduction.The main results are as follows:1. Fertilization have a significant impact on the Salix babylonica plantation soil organiccarbon mineralization characteristics. During the45days soil cultivation experiments in lab, soilorganic carbon mineralization rate in the early, mid, and overall process showes a rapid decline,slow decline and a smooth trend in the14kinds of fertilization treatments. N fertilizer is thebetter way to improve soil organic carbon mineralization rate and carbon mineralizationcumulative emission than P fertilizer, however, K fertilizer is the worst in the three conditions.Meanwhile, this effect is worse and worse following deepening of the soil. The impact on thecarbon mineralization cumulative emission is significant in the treatments of5,7,10,11, contraryto the3,6,8,compared with CK.2. The Salix babylonica plantation soil physical properties are not obvious in the14kinds offertilizer treatment. Soil density, maximum water holding capacity, field water capacity andcapillary moisture capacity, capillary porosity, capillary porosity, total porosity of treatment8increase0.97times,1.19times,1.12times,1.08times,1.16times,1.05times,1.16times with CK,which effect is best in all treatments.3. Fertilization has a significant impact on the Salix babylonica plantation chemicalproperties of soil. Fertilization have an obvious effect on hydrolyzed nitrogen, effectivephosphorus, rapidly-available potassium, and with the N,P,K fertilization increasing, theyincrease respectively. However, fertilization has no effect on total nitrogen, total phosphorus,total potassium, the influence of organic matter. In the14kinds of fertilizer treatments,Hydrolysis nitrogen in different soil showed the highest content in the treatment of the11（N₃P₂K₂）, respectively,115.84mg.kg^-1,104.65mg.kg^-1,83.31mg.kg^-1. The content of theeffective phosphorus is the highest treatment7（N₂P₃K₂）, respectively,7.43mg.kg^-1,4.80mg.kg^-1,1.07mg.kg^-1. At the same time, the content of the available potassium is the highest treatment10（N₂P₂K₃）, respectively,501.73mg.kg^-1,399.53mg.kg^-1,264.94mg.kg^-1. The sameprocessing, general chemistry indexes of different soil layer content showed a certain law ofdiminishing.4. The soil enzyme activity of plantation is strongly influenced by fertilization. In0-20cmsoil layer, urease activity and sucrase activity in the treatment of the3is the highest and the1.74times,1.36times with CK. Neutral phosphatase and catalase activities respectively in thetreatment of9and5are the highest. In20-40cm soil layer, urease activity and sucrase activityrespectively in the treatment of3,8are the highest. Neutral phosphatase activity and hydrogenperoxide were highest in the treatment4. In40-60cm soil layer, urease activity and sucraseactivity respectively in the treatment of4and7is the highest. Neutral phosphatase activity andcatalase activity is highest in treatment3,13, respectively, but indicate no obviously changedwith CK. Under different N levels, soil urease, invertase activity is one of the highest in N1,respectively, with significant difference was found in CK; Different levels of N neutralphosphatase and catalase were showed no significant difference. Under different P levels, ureaseactivity showed P3significantly higher than P₁, P₂, sucrase activity under P₂level minimum,neutral phosphatase and catalase affected by phosphate fertilizer. Under different K levels, ureaseactivity under the K₁level the highest, and sucrase, neutral phosphatase and catalase activitiesunder the K₁, K₂, K₃level change is not obvious. Four kinds of enzyme activity in different soillayer showed a certain law of diminishing.5. Fertilization has different effects on soil microbial biomass carbon in the plantations. In0-20cm soil layer, soil microbial biomass carbon content in the treatment3is the highest. Withthe increase of N, P, K fertilizer, soil microbial biomass carbon in a parabolic variation trend,suggests that too much fertilizer often result in microbial biomass carbon decreased instead. In20-40cm soil layer, the highest content is the treatment8. With the increase of N fertilizer, thecontent range is, N₀P₂K₂＞N₃P₂K₂＞N₁P₂K₂＞N₀P₀K₀＞N₂P₂K₂. Effect of K fertilizer0-20cmsoil layer are roughly the same condition of0-20cm soil layer.In40-60cm soil layer, soilmicrobial biomass carbon content of treatment11is significantly higher than CK,2.49times thatof CK. Under different N fertilizer level, treatment N₃P₂K₂content is the highest, andsignificantly higher than CK. High application of phosphorus fertilizer inhibit the increase of soilmicrobial biomass carbon, such as P₂, P3and CK was not significant under the level of content.Soil microbial biomass carbon in the level of K₂is significantly higher than that of CK, but K₁and K₃is not obvious compared with CK. In addition, in soil vertically, microbial biomasscarbon shows a roughly trend as following with the soil layer deepen the content decrease.6. In method of principal component analysis, the soil fertility quality score value was calculated.The treatment8rankes first.Thus, the treatment8is the best in improving the soil fertility.