Fertilizer management methods affect bacterial community structure and diversity in the maize rhizosphere soil of a coal mine reclamation area

Abstract

Background: The filling or mixed stack mode is a frequently used coal mine reclamation engineering technique that results in changes in soil microbial community structure and nutrient content, which lead to considerable deviations from the characteristics of restored coal mine reclamation areas that can be used for farming. Fertilization is an effective strategy for improving soil fertility in such areas; however, the response of soil bacterial communities, especially in the crop rhizosphere soil, to different fertilization techniques in such soils remains unclear. Therefore, we investigated the effects of different fertilization management methods, including no fertilizer, farmers' practice, inorganic fertilizer, organic fertilizer, and organic–inorganic fertilizer, on maize yield, rhizosphere soil bacterial community and diversity, soil physicochemical properties, and nitrogen cycle-related gene abundance (nifH, AOB, and nirS). Results: The results showed that organic–inorganic fertilizer treatment significantly improved maize yield. The relative abundance of the dominant phyla did not significantly differ between the treatment groups. However, the Chao 1 and Shannon indices of the bacterial community significantly changed between the no fertilizer and organic–inorganic fertilizer treatments. Notably, organic–inorganic fertilizer application significantly increased the copy numbers of nifH and nirS. Further, moisture, bulk density, and available phosphorus content were identified as the major driving factors responsible for the changes in bacterial community structure, diversity, and copy numbers of nifH, nirS, and AOB. Conclusions: The results of this study revealed that organic–inorganic fertilizer application improved soil bacterial diversity and the copy numbers of nifH and nirS in maize rhizosphere soil. Therefore, we concluded that organic–inorganic fertilizer is an effective strategy for the restoration of maize rhizosphere soil properties and bacterial communities in coal mine reclamation areas.