Weathered Coal Biotransformation: A Novel Approach to Improve Wind‐Sandy Soil Quality and Promoting Plant Growth

ABSTRACT Weathered coal (WC) is a unique coal resource that causes environmental pollution when stockpiled long but can be effectively used as a soil conditioner due to its high organic content. However, direct use of WC for soil amendment is not very efficient in utilizing its nutrients. In this study, WC was biotransformed using Phanerochaete chrysosporium and surfactant Tween‐80 to release small‐molecule humic acids from WC. Different proportions (0%, 1%, 3%, 5%, 7%, and 9%) of WC and weathered coal biotransformation product (WCB) were added to pots with wind‐sandy soil, and alfalfa ( M. sativa ) was grown in a greenhouse for 90 days. Our aim was to increase WC's small‐molecule humic acid content and explore WCB's amelioration effect and mechanism through plant growth indicators, photosynthesis, nutrient utilization efficiency, soil carbon (C), nitrogen (N), phosphorus (P), and soil enzyme activities. The results showed that WC increased the nutrients and nutrient availability of wind‐sand soil by releasing small humic acids through biotransformation and thus promoted plant growth. WCB was significantly better than WC in improving soil nutrients, soil nutrient availability, and plant growth, with 5% being the optimum level. Soil quick nutrients were significantly increased by 3–4 times in 5% WCB treatment. Plant height was significantly increased by 1.51 times and biomass by 17.6%. Plant nutrient utilization efficiency, net photosynthetic rate, transpiration rate, and stomatal conductance also increased significantly. Our research provides data support and potential evidence for wind‐sandy soil improvement and WC's efficient use.