Effect Of Different Nitrogen Fertilizers And Microbial Agents On The Decomposition Rate Of Rice Straw And Soil Nutrients

The crop yield of crops in China is large,and it takes a lot of manpower and material resources for farmers to deal with straw.If they do not deal with the farming activities that will affect the next year.In situ returning to the field can harmlessly treat straw and enhance soil fertility,which is one of the main methods for modern agricultural treatment of straw.Straw returning as an agricultural measure to improve soil organic carbon,improve soil structure and soil fertility,has been widely applied.The suitable time for returning rice straw to the field in Northeast China is about October to mid-November,and the time is about 40 days.After entering winter,the temperature is low and the time is long,which is not conducive to the decomposing of returning straw.In this experiment,the indoor method was used to simulate the external returning conditions,and the traditional method was modified.Under the shortterm suitable test conditions of 40 days,the nitrogen source material and the decomposing agent were added to the rice straw to adjust the C/N of the straw mixture,and the straw was decomposed.At each stage,the effects on straw index and physical index were measured and analyzed,in order to explore the effects of different nitrogen sources and microbial agents on the decomposition of rice straw and soil nutrients.The main findings are as follows:1.The addition of nitrogen source had obvious effects on the decomposing of rice straw in returning field,and there was a significant difference compared with the treatment group without nitrogen source.The physical properties of the three control treatment groups did not meet the decomposition standard.The fastest decomposition period of short-term returning straw residue is the 10 th to 30 th day.The best combination is the amino acid fermentation tail liquid with compound bacteria,the decomposing rate is 16.08%,and the average decomposing rate of nitrogen source bacteria treatment is 15.64.%,the decomposing rate of CK-1 treatment was 8.22%.There was no significant difference in the straw decomposing effect between the two microbial agents.2.Among the components of straw,the degree of decomposition: starch>hemicellulose>cellulose>lignin,the amino acid tail liquid has obvious promoting effect on the easily decomposed components in straw.F1 AM had the most obvious degradation effects on starch and hemicellulose.The degradation rates were 55.79% and 31.40%,respectively.The average decomposing rates of nitrogen source agents were 53.90% and 30.37%,respectively.The decomposing rate of CK-1 treatment was 36.08%.And 14.58%.F1 B had the most obvious degradation effect on cellulose,the degradation rate was 7.09%,the average decomposing rate of nitrogen source agent treatment was 6.68%,and the decomposing rate of CK-1 treatment was 1.36%.The effect of each treatment on the decomposition of lignin was not Significant differences.3.Short-term straw returning to the field can increase the available nitrogen and organic matter content of the soil in a small amount,and has less effect on soil total nitrogen.There was no significant difference in soil nutrient content between the control groups treated with the same treatment.All nitrogen treatment groups significantly reduced the fixation and percentage of ammonium nitrogen in the soil.The ammonium nitrogen content of each treatment decreased with the return of the field,while the soil nitrate nitrogen content increased with the returning time..The main source of soil nutrient enhancement in the short-term return to the field is fertilization.4.The amino acid fermentation tail liquid has obvious decomposing effect on the straw components,and it has the same lifting effect as the traditional nitrogen fertilizer on soil fertility,and is suitable for organic fertilizer application.