The Effects of Microbial Inoculants on Bacterial Communities of the Rhizosphere Soil of Maize

Minchong Shen,Qiyun Li,Keke Dang,Junwei Peng,Zhengkun Zhang,Jiangang Li,Hong Liu,Yu Zhao,Yuanhua Dong

doi:10.3390/agriculture11050389

Abstract

The bacterial community of rhizosphere soil maintains soil properties, regulates the microbiome, improves productivity, and sustains agriculture. However, the structure and function of bacterial communities have been interrupted or destroyed by unreasonable agricultural practices, especially the excessive use of chemical fertilizers. Microbial inoculants, regarded as harmless, effective, and environmentally friendly amendments, are receiving more attention. Herein, the effects of three microbial inoculants, inoculant M and two commercial inoculants (A and S), on bacterial communities of maize rhizosphere soil under three nitrogen application rates were compared. Bacterial communities treated with the inoculants were different from those of the non-inoculant control. The OTU (operational taxonomic unit) numbers and alpha diversity indices were decreased by three inoculants, except for the application of inoculant M in CF group. Beta diversity showed the different structures of bacterial communities changed by three inoculants compared with control. Furthermore, key phylotypes analyses exhibited the differences of biomarkers between different treatments visually. Overall, inoculant M had shared and unique abilities of regulating bacterial communities compared with the other two inoculants by increasing potentially beneficial bacteria and decreasing the negative. This work provides a theoretical basis for the application of microbial inoculants in sustainable agriculture.

Highlights

Bacterial communities of rhizosphere soil are of vital importance to the growth of field crops and agricultural productivity [1]
The growth of beneficial bacteria and the reduction in pathogens result from the interaction between the rhizosphere and roots of their host plants [4], which can simultaneously promote the growth of crops and enhance induced systemic resistance in host plants against pathogens, soil-borne diseases, and other environmental stresses caused by abiotic factors [5]
The bacterial community of rhizosphere soil is known to be associated with the status of agricultural soil: whether it is nutrient efficient [42], whether the elements are conveniently available for plants [43], whether it is sufficient for fertility [44], and whether

Summary

Introduction

Bacterial communities of rhizosphere soil are of vital importance to the growth of field crops and agricultural productivity [1]. The bacterial structure and function have changed due to current unreasonable agricultural practices implemented by human beings, including intensive cultivation, years of continuous cropping, and overuse of chemical fertilizers [7,8]. The overuse of chemical fertilizers has brought environmental problems to agricultural ecosystems by destroying the physiochemical processes of the soil [9,10], especially, the excessive use of nitrogen fertilizer resulted in soil acidification, environmental pollution, unbalance of nutrient [11]. It could affect the absorption of phosphorus by plants [12].

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Discussion

Conclusion