桑枝还田对土壤养分和微生物群落的影响OA北大核心CSTPCD

To investigate the effects of the amount of adding mulberry pruning debris and nitrogen application on soil nutrients and microbial communities in a mulberry orchard,a pot experiment was conducted using dried and milled mulberry pruning debris along with mulberry orchard soils by nylon bags.The experiment used two-factor variables,including the amount of adding mulberry pruning debris(full amounts,half amounts,and none)and nitrogen application methods[no nitrogen application,one-time application at the beginning,one-time application at 28 days,and twice application(beginning and 28 days)].The mulberry residues,soil physic-chemical properties and the structure of microbial communities based on 16S and ITS sequencing were assessed over a period of 35 days.The results showed that,the decomposition of mulberry pruning debris was primarily influenced by the methods of nitrogen application.The treatments of adding mulberry pruning debris significantly increased the soil organic matter compared to the non-addition treatments,while nitrogen application significantly increased the soil alkali-hydrolyzable nitrogen compared to the non-addition treatment.The amount of adding mulberry pruning debris was the main factor influencing soil microbial richness and diversity,and adding full amounts of mulberry pruning debris significantly reduced the Chao1 and Shannon indices of soil microorganisms compared to other treatments.Both mulberry pruning debris and nitrogen application could significantly influence the distribution of microbial communities,but the amount of adding mulberry pruning debris had a more significant impact on fungal distribution compared to nitrogen application methods.The results of redundant analysis(RDA)revealed a strong correlation between the microbial community distribution and the contents of soil pH,organic matter,and alkali-hydrolyzable nitrogen.The addition of mulberry pruning debris highly significantly increased the relative abundance of Sordariomycetes,while the application of nitrogen highly significantly increased the relative abundance of Nitrospira.The addition of mulberry pruning debris resulted in a significant enrichment of Microbacterium,Ellin6067,MND1,Sporosarcina,Pseudomonas,Streptomyces,Acremonium,Gibellulopsis,and Ciboria compared to treatments without debris.Further analysis of the potential ecological functions of the enriched fungi revealed that the decomposition of mulberry pruning debris primarily increased the relative abundance of saprotrophic fungi.Specifically,there was an increase to 58.96%and 58.39%in treatments with full and half-amounts of pruning debris respectively,compared to only 23.74%in treatments without any additions.This study establishes a theoretical framework for elucidating the microecological impacts of mulberry prunings incorporated into the field.