Effects Of Simulated Nitrogen Deposition On Nutrient Release And Soil Fertility Of Cinnamomum Migao Leaves Liiter

Nowadays,the input of nitrogen to terrestrial ecosystems is increasing globally,and it is especially important to change the decomposition of vegetation and soil physiological and biochemical properties,which is of great significance for maintaining energy flow and material nutrient cycling in ecosystems.In this study,the field experiment of nitrogen deposition was carried out with Cinnamomum migao H.W.Li litter leaves as the research object.Different concentrations of nitrogen were applied to determine the decomposition rate of rice bran and nutrients,soil nutrients and enzyme activities,revealing the increasing nitrogen deposition.Under the environment,the effects of leaf litter decomposition and soil fertility can fully understand the nutritional cycle of C.Migao,and provide a theoretical basis and basis for the latter to further study C.Migao.The specific results are as follows:(1)The nitrogen deposition group has a certain inhibitory effect on the decomposition of rice leaf litter,and the greater the concentration,the more obvious the inhibition effect.The decomposition coefficient K is numerically simulated by the decomposition exponential decay improvement model: 0.098,0.090,0.099,0.083.Under the condition of N2,the decomposition rate of rice bran is the fastest,and the time for simulating the decomposition of 50% is consistent with the actual time.The model simulation is better,and the decomposition of 95% requires 2.547,2.774,2.522,and 3.008.(2)The content of C,N,P and K in litter in the nitrogen application group was significantly higher than that in the control group(p<0.05),which inhibited the release of nutrients and promoted its own nutrient content.The C/N and C/P values of litter showed a decreasing trend,and the N/P change was the trend of decrease-increasing-decreasing.(3)Under the condition of nitrogen deposition,the pH value of the soil in the nitrogen application group is lower than that of the control group,and the soil is slightly acidified.For the soil moisture content,the water content of the control group was larger than that of the nitrogen application group,but there was no significant difference between the nitrogen treatment groups.(4)Under the condition of nitrogen treatment,the soil organic matter was slightly higher than the control group,which had a slight micro-promoting effect;it had no obvious effect on the total nitrogen content;it had an inhibitory effect on the total phosphorus content,and the nitrogen application had no significant effect on the total potassium content of the soil;The hydrolyzednitrogen showed a promoting effect under the addition of low-medium concentration nitrogen,and the inhibitory effect was observed at high concentration;the change of available phosphorus content showed a low promotion and high inhibition phenomenon;the effective phosphorus content gradually changed from micro-promotion in the early stage to micro-inhibition,and High nitrogen treatment had stronger inhibition in the later stage;simulated nitrogen deposition had no effect on soil C/N value,but promoted soil C/P value and N/P ratio.Among the relationships between litter nutrients and soil nutrients,the data were different in different seasons.The N,K and P of litter had a positive correlation with soil total nitrogen,hydrolyzed nitrogen and organic matter,and the ratio of litter nutrient ratio.The content of C and C showed a negative correlation with the elements N,K and P,indicating that the change of nutrient ratio in C.Migao litter leaves was mainly affected by the content of N and P.(5)Nitrogen treatment is beneficial to increase the activity of urease,sucrase and phosphatase;it has a certain inhibitory effect on the activity of soil catalase.According to the relationship between soil enzymes and soil factors,there is a strong negative correlation between urease and soil nitrogen;there is no obvious uniform correlation between invertase;strong positive between phosphatase and soil phosphorus.Correlation;catalase has a strong correlation with organic matter.(6)Through the principal component analysis of soil nutrient and enzyme activity,the changes of soil fertility in the simulated nitrogen deposition test were evaluated.Nine indicators were selected and the soil comprehensive fertility index was calculated as follows:N2>N1>CK>N3.It indicates that the appropriate nitrogen addition can promote the soil fertility,and the nitrogen concentration is too high to inhibit.