芍药种植密度对土壤微生物残体碳累积的影响OA

As a key component of soil organic carbon,the accumulation of microbial residues is regulated by various environmental and biological factors.However,there is currently a lack of systematic and in-depth research or clear conclusions regarding how flowering plants affect the accumulation dynamics and formation characteristics of microbial residue carbon under different planting densities.This study,conducted over four consecutive years,analyzed the effects of soil physicochemical properties,microbial community structure,and extracellular enzyme activities on the accumulation of microbial residue carbon in peony soils under different planting densities(CK,low density,medium density,and high density).The results showed that,(1)Compared with CK,the low and medium planting densities significantly increased soil organic carbon by 10.9%and 33.9%,total nitrogen by 20.5%and 83.3%,available nitrogen by 5.6%and 19.9%,and available phosphorus by 3.8%,27.8%,respectively,while significantly reduced soil pH by 12.1%and 28.9%,respectively(P<0.05).(2)The soil microbial biomass carbon and nitrogen,enzyme activity,and microbial residue carbon showed the highest at the medium density,which were significantly higher than other treatments(P<0.05),while CK and high density were the lowest,with no significant difference between them(P>0.05),indicating that the meddle planting density significantly increased soil microbial biomass carbon and nitrogen,soil enzyme activity,and microbial residue carbon,while high planting density inhibited soil microbial biomass carbon and nitrogen,soil enzyme activity,and microbial residue carbon.(3)The results of structural equation and redundancy analysis showed that higher microbial characteristics and enzyme activities were conducive to the accumulation of bacterial residue carbon,but not conducive to the accumulation of fungal residue carbon.The planting density had no significant effect on bacterial residue carbon,but was conducive to the accumulation of fungal residue carbon.Soil pH,microbial biomass carbon,and carbohydrate hydrolase were the soil single factors that had a significant effect on the accumulation of soil microbial residue carbon.In summary,in the cultivation of peonies,a moderate planting density could increase soil nutrient content and enzyme activity,and increase microbial residue carbon content and its contribution to the organic carbon pool.