Effects Of Different Fertilization Patterns On The Microbial Community Of Paddy Soil Under Straw Returning To Field

In order to further analyze the effects of straw returning on soil nutrient characteristics and microflora,this experiment refers to the rice-wheat rotation system using wheat-rice stalking period to carry out straw returning and nitrogen fertilizer forward pot experiment,and study the different application of straw returning mode.The effects of nitrogen fertilizer on soil and surface water nitrogen transformation,and the effects of different fertilization modes on soil nutrient and microbial community structure in paddy fields were studied by PLFA and Biolog.The following conclusions were drawn:?1?By analyzing the contents of ammonia nitrogen,nitrate nitrogen and nitrite nitrogen in soil and surface water under different nitrogen fertilizer treatments,it can be known that:?1?The content of ammonia nitrogen in urea and biogas slurry treatment in soil was always higher than that of ammonium bicarbonate,no straw returning and straw returning.The nitrate content of urea treatment was significantly higher than that of other treatments.?2?The content of ammonia nitrogen in the treatment of ammonium bicarbonate and biogas slurry in the surface water was higher than other treatments.The content of nitrate nitrogen was the highest without straw returning,and the treatment of biogas slurry and urea was higher than other treatments when the nitrite nitrogen content was 14 d.?3?After 14 days,the content of ammonia nitrogen and nitrate nitrogen in biogas slurry and urea treatment was second only to ammonium bicarbonate in soil and field water,but its total nitrogen content was much higher than that of ammonium bicarbonate,which could be used as straw returning.Nitrogen fertilizer.?2?Soil nutrient and microbial community results under different fertilization patterns in the mouthwash period:?1?Straw returning can increase the available potassium content of each treatment,and the alkali nitrogen content of nitrogen fertilizer advancement and biogas slurry treatment is significantly higher than that of conventional fertilization treatment.?2?The lignocellulose content of other treatments except for the biogas slurry treatment showed cellulose>hemicellulose>lignin,and the biogas slurry treatment showed cellulose>lignin>hemicellulose;biogas slurry application or The forward movement of nitrogen fertilizer can effectively improve the decomposing rate of straw.?3?Straw returning can improve the carbon source utilization ability of soil microbes in each treatment.The utilization of carbon source by nitrogen fertilizer advancement and biogas slurry treatment is always higher than that of conventional fertilization and blank,and Shannon index and Pielou index of biogas slurry treatment.Higher,the Simpson index of nitrogen fertilizer advancement is higher.?4?The soil microbial biomass of straw treated in the field was significantly higher than that of the blank at 7 d and14 d,and the bacteria were the absolute dominant bacteria in the paddy soil.Principal component analysis showed that the microorganisms that played a leading role in paddy soil during the mouthwash period were mainly bacteria and actinomycetes.?5?There was a significant negative correlation between alkali nitrogen and total PLFA content of phenolic acid and fungi;effective phosphorus was significantly positively correlated with amino acid,and positively correlated with carbohydrate and polymer;available potassium and bacterial total PLFA,actinomycete total PLFA The polymer is highly positively correlated with a significant positive correlation with carbohydrates,amino acids,amines,phenolic acids,and carboxylic acids.?3?Through analysis of soil nutrients,plant nutrients and microbial communities in different growth stages of rice:?1?The content of available potassium and alkali nitrogen in soil was the lowest at booting stage,and the available phosphorus content was the lowest at maturity.When the fertilization amount was 18 kg N·?666.7 m²?^-1,the available phosphorus content was the highest.The available potassium content of straw returning treatment was higher than blank.?2?The total nitrogen content of rice treated with straw returned to the field was higher than that of the blank,and the total potassium content was lower than the blank.Except for S1F1T2 and S1F1T3,the total phosphorus content of other treatments was higher than the blank,when the fertilization amount was 18 kg N·?666.7 m²?^-1When the amount of fertilizer is applied,the total potassium content is the highest.?3?Compared with the treatment without returning the field,straw returning can effectively improve the decomposing rate of straw.Except for blank,S1F1T1 and S1F2T3,the other processed lignocellulose content is lignin>hemicellulose>cellulose.Blank,S1F1T1 and S1F2T3 behaved as lignin>cellulose>hemicellulose.?4?When the fertilization amount is 15 kg N·?666.7 m²?^-1,the forward return of nitrogen fertilizer can significantly increase the carbon source metabolic intensity of the soil in paddy soil.Excessive fertilization will lead to a decrease in species diversity and homogeneity;the application of biogas slurry will help to increase the number of dominant microbial populations.?5?The soil microbial biomass of straw treated in the field was significantly higher than that of the blank.When the straw was returned to the field and the nitrogen fertilizer was moved forward(the fertilization amount was 15 kg N·?666.7 m²?^-1),the microbial biomass could be significantly increased and the microbial growth could be promoted;Absolute dominant flora in paddy soil.Principal component analysis and B/F values showed that the conventional fertilization and nitrogen fertilizer advance treatment may have pathogenic risks,so the optimal treatment of biogas slurry was selected.?6?There was a significant positive correlation between available phosphorus and total PLFA and total PLFA of actinomycetes,and a significant positive correlation with total PLFA of fungi.