Long-term greenhouse vegetable cultivation alters the community structures of soil ammonia oxidizers

Abstract

Purpose

Continuous cropping obstacles derived from long-term intensive cultivation has severely affected the healthy development of greenhouse vegetable industry in China. The alterations in soil microbial communities are commonly thought to be the important reasons behind continuous cropping obstacles. However, little attention is focused on soil functional microorganisms, such as soil ammonia oxidizers, which convert NH₃ to NO₂⁻ in soils and play an important role in terrestrial ecosystem N cycling.

Materials and methods

With the help of quantitative real-time PCR and high-throughput sequencing methods, this study investigated the effects of consecutive greenhouse vegetable cultivation on the abundances and community structures of ammonia-oxidizing archaea (AOA) and bacteria (AOB).

Results and discussion

Continuous greenhouse production significantly affected soil physicochemical properties but slightly influenced on soil biochemical properties. Long-term greenhouse production significantly decreased soil potential nitrification rates. The abundances of AOA and AOB were insensitive to continuous greenhouse cultivation, whereas their community structures were significantly altered. A significant increase in average relative abundance of Nitrososphaerales Clade B4 in AOA community was observed after long-term greenhouse cultivation but just the opposite for Nitrososphaerales Clade Nitrososphaera. Increasing greenhouse cultivation years decreased the average relative abundance of Nitrosospira in AOB community, and their ecological niches were gradually occupied by Nitrosomonas; consequently, Nitrosomonas dominated AOB community under long-term greenhouse vegetable cultivation. Soil physicochemical properties, but not biological activity, were directly linked to the shifts of community structures of ammonia oxidizers. Moisture and total nitrogen significantly regulated AOA community structure, whereas organic matter and salinity mediated that of AOB.

Conclusions

Our results demonstrated that consecutive greenhouse production obviously affected soil N turnover through altering community structures of nitrifiers, and soil functional microorganisms should be taken more attention when exploring the mechanisms for continuous cropping obstacles of greenhouse vegetable. The current study also highlights the fast adaptation of both AOA and AOB communities to complexly varied soil physicochemical environments.

from Energy Ecology Environment Ambio via Terpsi Hori on Inoreader http://bit.ly/2UqKZrB