| Desertified soil is one of the most critical types of degraded soil.The research that restore those desertified soil has a great influence on forestry and husbandry in Ningxia or North China.Researchers added organic materials to study the desertified soil's improvement process and toke the plant growth as an important index.They also concluded that the carbon nitrogen content and microbial community changes of plant rhizosphere soil is an important reference index in soil improvement.Our study selected the local poplar branches,corn straws and nitrogen fertilizer(urea)as materials,using the simulation experiment with field experiment to study the improving effects of organic material with different application rate of nitrogen fertilizer on wolfberry rhizospheret soil's carbon,nitrogen and it's component content,soil enzyme activity,microbial functional diversity,genetic diversity of Ningxia sandy land.The study is the two factors Latin side experimental design,the main plot for organic material incorporation includes:no incorporation(N),branch incorporation(B,7500 kg/hm2),straw incorporation(S,7500 kg/hm2),subplot for different application rate of nitrogen fertilizer:N1:166.5 kg/hm2,N2:199.8 kg/hm2,N3:233.1 kg/hm2,nine treatments total.Each treatments have 3 replicates,the period is two years.The main results are as follows:(1)The simulated mineralization experiment results showed that:the carbon cumulative mineralization amount of all kinds treatments are 0.65-0.88g.kg-1(N),0.58-0.99g.kg-1(B),0.63-1.44g.kg_'(S)respectively.At the same N application rate,the mineralization cumulative amount of soil carbon and nitrogen of all kind of treatments present S>B>N order,which increased or decreased after first rise with the increased of N application rate of organic material.Organic material,nitrogen fertilizer and the interaction of them in general significantly influence on soil mineralization cumulative amount(F>F0.01).Organic material with nitrogen fertilizer promoted the carbon and nitrogen mineralization.(2)The carbon and nitrogen of wolfberry rhizosphere soil results showed that The change law of carbon,nitrogen contents and enzyme activities in October and August of 2016 and june of 2017 were similar in general.In the same application rate of carbon,nitrogen and its components contents,enzymes activity of all treatments presented S>B>N.Under the group of organic material incorporation,carbon(except for the organic carbon of N and B),nitrogen and enzymes activity of all treatments increased with the promote of N application rate.(3)The wolfberry rhizosphere soil's microbial community functional diversity result showed that the application of organic material and nitrogen fertilizer increased the utilization amount of carbon source and enhanced microbial metabolic activity.The first three utilization of carbon source is the amino acid,polymer and carboxylic acid.Straw incorporation with nitrogen fertilizer treatments shows better effect on promotion utilization of carbon source of microbe.In 168h,the AWCD value of SN3 was the largest in all treatemnts,also the microbial diversity index improved significantly.The utilization intensity of various carbon sources are closely related to soil organic carbon and carbon components,and the microbial diversity index is closely related to the organic carbon and inorganic nitrogen.The wolfberry rhizosphere soil's microbial community genetic structure showed that proteobacteria,bacteroidetes,acidobateria,actinomycetes,planctomycetes,firmicutes are the first six most abundant bacteriophyta of bacteria.Ascomycota is the most abundant eumycota of fungi.overall,organic materials with nitrogen fertilizer increasing the contents of carbon and nitrogen and mineralization accumulative account,enzymes activity in sandy soil,also improving the soil microbial community structure. |
PDF Full Text Request