Response of soil bacterial community to bioorganic fertilizer application as a weed management strategy in rice paddy

Abstract

Background: The growth of weed is common problem in rice cropping, leading to the application of herbicidal substances to suppress weed growth. Weed biocontrol through novel bioorganic fertilizer (BIO) has been established in rice cultivation, however, its main herbicidal components and influence on soil bacterial community are unknown.Results: We identified three herbicidal components, hexadecanoic, isovaleric, and 2-methylbutyric acids, in BIO extract. We conducted 16S rRNA sequencing to identify changes in soil bacterial community in response to BIO treatments and performed a RDA analysis with soil chemical properties and weed-control effect. The OTU, Chao1 and Shannon indices did not differ substantially among the BIO treatments, and the bacterial diversity was not significantly affected by BIO. As result from PCA analysis, we discovered that soil bacterial community was not significantly influenced by BIO. We identified six dominant phyla (Proteobacteria, Acidobacteria, Chloroflexi, Nitrospirae, and Verrucomicrobia) in BIO-treated paddies. The five most abundant genera were Anaeromyxobacter, Candidatus Nitrosotalea, Clostridum sensustricto1, Haliangium and Candidatus Nitrotoga. From the RDA analysis, the highest correlations were obtained for soil pH, total K, and Pseudomonas. The weed-control effect mostly correlated with the abundance of Candidatus Koribacter, Clostridium sebsustricto 9, and Nonomuraea. Rice yield had a distinct relationship with Nonomuraea, Nitrospira, and Candidatus Koribacter.Conclusions: With the changes in soil pH and total K, BIO could impact bacterial communities and weed control, and in turn affect rice yield. This foundation can be helpful that application BIO is a “not harmful” and feasibility weed biocontrol strategy.