Objectives We studied the ecological restoration effect of three kinds of AM fungi on abandoned ionic rare earth mining areas, to provide technical support for the efficient remediation and cultivation of the abandoned mining land.
Methods The experiment was carried out by pot culture and the test crop was ryegrass. The test soil was collected from a waste mining area in Dingnan County of Ganzhou City, Jiangxi Province. The soil was sterilized, then inoculated with Glomus mosseae (G.m), Rhizophagus intraradices (R.i) and Glomus etunicatum (G.e), respectively, and the soil without inoculation was used as the blank group, and each treatment was repeated 6 times. Plant height was measured 8 times since the 10th day of ryegrass growth. At the 8th measurement (195 days growth), three pots of ryegrass plants were harvested for aboveground and root dry weight and NPK content measurement, and rhizosphere soil samples were collected to analyze pH, organic matter, total and available NPK contents. The remaining three pots were not watered for drought stress treatment, and the plant superoxide dismutase (SOD) activity and proline content were determined on the 210 days of growth.
Results Compared with the control, G.m, R.i and G.e inoculation increased rhizosphere soil pH from strong acid (4.60) to 7.62–7.90, organic matter by 123.9%, 126.8% and 105.0%, and plant height by 38.13%, 34.53% and 25.33% respectively. Compared to other treatments, G.m inoculation increased total N, available N and total P in rhizosphere soil by 64.17%, 59.93% and 84.12%, respectively. Compared to other treatments, R.i inoculation increased available K by 73.31%, aboveground dry weight of ryegrass by 43.73%, and root N, P and K content by 58.60%, 83.27% and 45.60%, respectively. After 4 days of drought stress, plant SOD activity increased by 7.35%, 15.94% and 4.68%, and proline content increased by 34.94%, 36.66% and 16.87% under G.m, Ri and G.e., respectively.
Conclusions AM fungi inoculation significantly increased rhizosphere soil pH and organic matter, and nutrient content to different extent, and significantly increased plant growth and dry matter accumulation in above and below ground. AM fungi inoculation also showed signs of increasing ryegrass drought resistance at the late growing stage. Therefore, AM fungi inoculation is beneficial for the ecological restoration of waste mining areas.
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