Optimizing Amendment Ratios for Sustainable Recovery of Aeolian Sandy Soils in Coal Mining Subsidence Areas: An Orthogonal Experiment on Medicago sativa

Lijun Hao, Zhenqi Hu (), Qi Bian, Xuyang Jiang, Yingjia Cao, Changjiang Li and Ruihao Cui
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Lijun Hao: School of Environment Science and Spatial Informatics, China University of Mining and Technology, Xuzhou 221116, China
Zhenqi Hu: School of Environment Science and Spatial Informatics, China University of Mining and Technology, Xuzhou 221116, China
Qi Bian: School of Environment Science and Spatial Informatics, China University of Mining and Technology, Xuzhou 221116, China
Xuyang Jiang: School of Environment Science and Spatial Informatics, China University of Mining and Technology, Xuzhou 221116, China
Yingjia Cao: School of Environment Science and Spatial Informatics, China University of Mining and Technology, Xuzhou 221116, China
Changjiang Li: School of Environment Science and Spatial Informatics, China University of Mining and Technology, Xuzhou 221116, China
Ruihao Cui: School of Environment Science and Spatial Informatics, China University of Mining and Technology, Xuzhou 221116, China

Sustainability, 2025, vol. 17, issue 20, 1-15

Abstract: Coal mining in the aeolian sandy regions of western China has caused extensive land degradation. Traditional single-component soil amendments have proven inadequate for ecological restoration, underscoring the need for integrated and sustainable strategies to restore soil fertility and vegetation. A pot experiment using alfalfa ( Medicago sativa L.) evaluated the effects of weathered coal, cow manure, and potassium polyacrylate combined in a three-factor three-level orthogonal design on plant growth, nutrient uptake, and soil properties. Results showed that compared with the control (C0O0P0), amendment treatments significantly increased alfalfa fresh weight (+47.57~107.38%), dry weight (+43.46~104.93%), plant height (+43.46~104.93%), and stem diameter (+12.62~31.52%), along with improved plant phosphorus and potassium concentrations (+15.41~46.65%). Soil fertility was also notably enhanced, with increases in soil organic matter, total nitrogen (TN), total phosphorus (TP), available nitrogen (AN), available phosphorus (AP), and available potassium (AK) ranging from 4.25% to 777.78%. In contrast, soil pH and bulk density were significantly reduced. The optimal amendment combination was identified as 10 g·kg −1 weathered coal, 5 g·kg −1 cow manure, and 0.6 g·kg −1 potassium polyacrylate. Structural equation modeling revealed that the amendments promoted plant growth both directly by improving soil conditions and indirectly by enhancing nutrient uptake. However, high doses (30 g·kg −1 ) of weathered coal may inhibit plant growth, and the co-application of high-dose weathered coal or manure with potassium polyacrylate may lead to antagonistic effects. This study provides fundamental insights into soil–plant interactions and proposes a sustainable amendment strategy for improving aeolian sandy soils, which could support future ecological reclamation efforts in coal mining area.

Keywords: coal mining subsidence area; aeolian sandy soil; weathered coal; organic fertilizer; potassium polyacrylate; sustainability; ecological restoration (search for similar items in EconPapers)
JEL-codes: O13 Q Q0 Q2 Q3 Q5 Q56 (search for similar items in EconPapers)
Date: 2025
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