Responses of soil microbial community activities and soil physicochemical properties to coal fly ash soil amendment

Abstract

Abstract With the rapid development of industry, the consumption of coal has been increasing, and several hundred millions tons of coal fly ash are produced annually worldwide. Direct application of coal fly ash to agricultural production poses ecological risk of heavy metal pollution with low land productivity. In this study, a field experiment of coal fly ash soil amendment was conducted in Hebei province, China. The coal fly ash soil field was added with the carrier soil (CS, without containing coal fly ash) at different rate (0–40% mass content) in 0-20cm top soil layer, mixed with a rotovator, and then added with 0.45–1.80 kg·m− 2 soil amendment G1 for planting maize. The effect of soil amendments on soil physicochemical properties, maize yield, especially on soil microbial community activities were investigated in coal fly ash soil field. The results showed that G1 amendment improved the soil chemical properties and physical structure by increasing soil bulk density and soil macroaggregates. The highest maize yield was observed in B5 treatment (20% CS and 1.3500 kg·m− 2 G1). Meanwhile, the abundance of microorganisms facilitating the circulation of soil nutrients such as Acidobacteria (77.05%), Sphingomonas (25.60%), Nitrospira (20.78%), Streptomyces (11.32%), and Gaiella (10.20%) was increased. Overall, our results reveal that coal fly ash soil amendment can improve soil microbial functions, thus enhancing soil sustainability. Our findings provide the reference for the development and application of coal fly ash soil amendments.