Effects of AMF cooperating with exogenous calcium on maize growth and soil improvement

Abstract: Shendong mining area, with the first coal output and larger subsidence area in China, is the largest coalfield in China and also one of the seven major coalfields in the world. Shendong mining area belongs to the typical semi-arid, semi-desert plateau continental climate. Many regions, with dry climate, scarce rainfall, adequate light, strong evaporation, and dry air, are extremely unfavorable to the growth of plants. Ecological environment in the mining area is fragile and vulnerable to damage. Coal mining would severely damage soil and plants. Underground mining would cause ground subsidence damage and produce large amounts of crack, resulting in losses of surface moisture and nutrient and intensifying drought. Therefore, water is limiting factor for agricultural production in Shendong mining area. In order to relieve the destruction of the agricultural production and surface environment caused by coal mining in Shendong mining area. The synergistic effects of the exogenous calcium and the AMF on the growth of maize at seedling were investigated by simulating experiments, with the degraded soils and maize as the test matrix and test plant respectively, simulating the characteristics of drought and water shortage of Shendong mining area. Tested strains are from Beijing Academy of Agricultural and Forestry Sciences. Glomus mosseae propagation was conducted in laboratory. The spores of AMF account for 63 strains per gram dry soil. The concentrations of exogenous calcium are 5, 10, 20, 40, 80 mmol/L respectively. The results showed that the synergistic effect of 20 mmol/L exogenous calcium and AMF was optimal, which significantly increased the biomass, tissue water content and leaf color value of maize; an average dry weight of maize per plant reached to 94.1%, tissue water content and leaf color value were 91.68% and 43.67 respectively; and the nitrogen, phosphorus and potassium accumulation were significantly higher than those of other treatments. At the same time, the glomalin in maize rhizosphere soil increased obviously, the concentration for total glomalin and easily extractable glomalin were 4.3 and 1.6 mg/g respectively, and the content of soil organic matter increased significantly. The combined effects of the AMF and the exogenous calcium could be beneficial to the maize growth and alleviate the impact of drought stress on maize and significantly improve the degraded soils in mine area. In this paper, the experiment mainly investigated the effect of AMF on the degraded soil in mining area. It will be of more interest and instructive meaning for the use of AMF on the degraded soil, if the technology can be carried out for long term and systematically studied. For Shendong mining area located in arid and semi-arid region, application of AMF and a certain concentration of exogenous calcium would help for improving agricultural production, which would also be important meaning for environmental protection and ecological restoration in mining area.