杉木不同套种模式对土壤氮素及反硝化作用的影响OA

Interplanting patterns of Cunninghamia lanceolata(CL)plantations exert significant impacts on soil nitrogen cycling in forests.This study selected the interplanting of C.lanceolata with Phoebe bournei(PB),Taxus wallichiana(TW),as well as the simultaneous interplanting with P.bournei and T.wallichiana,to investigate the effects of different interplanting patterns on soil nitrogen and denitrification.The results showed that compared with C.lanceolata monocultures,the CL×TW treatment significantly decreased soil ammonium nitrogen,total carbon,and total nitrogen contents;the CL×PB×TW treatment significantly increased soil nitrate nitrogen and total nitrogen contents.Compared to C.lanceolata monocultures,potential denitrification rates increased by 37.13%in the CL×PB treatment,while they decreased by 59.10%in the CL×TW treatment.Dif-ferent interplanting patterns showed significant differences in the abundance of the nirK gene.Ran-dom forest analysis indicated that microbial biomass carbon,microbial biomass nitrogen,ammoni-um nitrogen,total carbon contents and the abundance of the narG gene were the primary limiting factors for soil potential denitrification rates.In conclusion,the simultaneous interplanting with Phoebe bournei and Taxus wallichiana in Chinese fir plantations is conducive to the accumulation of nitrogen in the forest soil,which provides a scientific reference for nitrogen management and sus-tainable management of Chinese fir plantations.