Effects Of Manure Application On The Health Of Paddy Soil Ecosystem

Soil is the cornerstone of farmland ecosystems,and farmland soil health is also an important foundation for sustainable agricultural development.Systematically studies and health evaluation index system were constructed in this study,including soil environment,nutrients,biology,respiration and other indicators.Rice field in Chongming Island was selected to carry out the field test.Pig manure and the organic fertilizer were applied on the test field.High-throughput sequencing,HPLC-MS/MS and q PCR were used,and the rice field soil health after manure application was systematically evaluated.The health index and the comprehensive index method were adapted to evaluate the health of the soil ecosystem and the impact of pig manure and organic fertilizer application on the soil health of paddy fields was discussed.The main results are as follows:（1）Systematic soil health evaluation index and evaluation method were conducted.The indicator system includes 4 first-level indicators,which were soil environment,soil nutrients,soil organisms and soil respiration,as well as 9 secondary indicators and 35 tertiary indicators.The soil environment indicators includes soil p H,heavy metals,antibiotics and resistance genes;soil nutrients indicators include soil organic matter,total nitrogen,total phosphorus and total potassium;soil organisms indicators include soil microbial diversity and enzyme activity;soil respiration indicators includes soil respiration rate and greenhouse gas emissions（CH₄ and N₂O）.According to fuzzy mathematics,the membership function between soil health index and soil function was established,and the ups and downs of the membership function distribution were determined according to the factor load of the principal components.Finally,the comprehensive index method was used to comprehensively evaluate the health of the soil ecosystem.（2）Manure application had varying degrees of impact on the health indicators of farmland soil ecosystem.The results of the three field test treatment groups of pig manure group（PM）,organic fertilizer group（OF）and control group（CK）showed that the application of manure adjusted the p H of the soil to make it weakly alkaline,but had a negative effect on the content of heavy metals in the soil.The impact was small,and the difference between the 3 treatment groups was not obvious.The application of manure increased the content of soil antibiotics.The OTC content of PM group was higher than that of CK group in different periods,and the highest value was 20.69g·kg^-1 at the heading stage;it also increased the abundance of resistance genes in the soil.During the blooming and maturity stages,the gene copy numbers of int I1,sul1,sul2,tet Q and tet W in the fertilization group were significantly higher than those in the CK group（p<0.05）.The application of manure increased the soil organic matter in the paddy field.At the heading stage,the organic matter content of the PM group was significantly higher than that of the OF and CK groups（p<0.05）,and both were higher than 5.00 g·kg^-1.The soil total phosphorus,total nitrogen and total potassium content of the fertilization group were higher than those of the CK group,and the total phosphorus content increased to a significant level at the tillering stage,heading stage and blooming stage（p<0.05）,and the total nitrogen of the OF group was significantly higher than that of CK in the mature stage and PM group（p<0.05）,the total potassium content of OF group was the highest in blooming stage.After the application of manure,there were no significant differences in soil enzyme content,microbial diversity and richness in the three treatment groups,but the impact on soil respiration indicators was more significant.The application of pig manure and organic manure increased the soil respiration rate at the heading stage,blooming stage and maturity stage.The PM group was the most obvious,reaching a significant level at the heading stage（p<0.05）.（3）The evaluation results of soil ecosystem health showed that the application of organic fertilizer were more beneficial to soil health.Based on the established soil health evaluation system,determine the health index calculation and classification methods,combined with the on-site observation results,evaluate the soil health of the paddy field after fertilization.The results showed that soil nutrients and soil organisms are the key indicators that affect the health of the soil ecosystem in the paddy field.The comprehensive soil health index after organic fertilizer application was 0.6177;followed by the pig manure application group,which was 0.4323;and the control group was the lowest,which is 0.4200.The soil health of the OF group was grade II,which was a healthy state,while the PM and CK groups were both grade III,which was a sub-health state.The application of organic fertilizer increases the nutrient and microbial diversity in the soil,and had little impact on the quality of the soil environment,which significantly improved the health of the soil ecosystem;while the application of pig manure also increased the nutrient content of the soil,but it was not treated The application of fresh pig manure also increased the concentration of pollutants such as heavy metals and antibiotics in the soil,resulted in a lower comprehensive health index value.