Rock-Solubilizing Microbial Inoculums Have Enormous Potential as Ecological Remediation Agents to Promote Plant Growth

• Main Authors: Zhaohui Jia, Miaojing Meng, Chong Li, Bo Zhang, Lu Zhai, Xin Liu, Shilin Ma, Xuefei Cheng, Jinchi Zhang
• Format: Article
• Language: English
• Published: MDPI AG 2021-03-01
• Series: Forests
• Subjects: rock-solubilizing microbial inoculums; ecological restoration of carbonate mining area; plant growth; root nodule
• Online Access: https://www.mdpi.com/1999-4907/12/3/357

Anthropogenic<b> </b>overexploitation poses significant threats to the ecosystems that surround mining sites, which also have tremendous negative impacts on human health and society safety. The technological capacity of the ecological restoration of mine sites is imminent, however, it remains a challenge to sustain the green restorative effects of ecological reconstruction. As a promising and environmentally friendly method, the use of microbial technologies to improve existing ecological restoration strategies have shown to be effective. Nonetheless, research into the mechanisms and influences of rock-solubilizing microbial inoculums on plant growth is negligible and the lack of this knowledge inhibits the broader application of this technology. We compared the effects of rock-solubilizing microbial inoculums on two plant species. The results revealed that rock-solubilizing microbial inoculums significantly increased the number of nodules and the total nodule volume of <i>Robinia pseudoacacia</i> L. but not of <i>Lespedeza bicolor </i>Turcz. The reason of the opposite reactions is possibly because the growth of <i>R. pseudoacacia</i> was significantly correlated with nodule formation, whereas <i>L. bicolor</i><i>’</i>s growth index was more closely related to soil characteristics and if soil nitrogen content was sufficient to support its growth.<i> </i>Further, we found that soil sucrase activity contributed the most to the height of <i>R. pseudoacacia</i>, and the total volume of root nodules contributed most to its ground diameter and leaf area. Differently, we found a high contribution of total soil carbon to seedling height and ground diameter of <i>L. bicolor</i>, and the soil phosphatase activity contributed the most to the <i>L. bicolor’ s</i> leaf area. Our work suggests that the addition of rock-solubilizing microbial inoculums can enhance the supply capacity of soil nutrients and the ability of plants to take up nutrients for the promotion of plant growth. Altogether, our study provides technical support for the practical application of rock-solubilizing microbes on bare rock in the future.