The Effect of a Fly Ash-Based Soil Conditioner on Corn and Wheat Yield and Risk Analysis of Heavy Metal Contamination

The utilization of coal fly ash (CFA) as a soil conditioner has been a research hotspot in recent years. In this paper, the continuity and stability of the yield-increasing effect of a fly ash-based soil conditioner were investigated through field trials for three consecutive years. The yield-increasing effect and applicability were also investigated by planting a variety of crops in different types of soil. Field test results revealed that the new fly ash-based soil conditioner had wide adaptability and stability under the condition of reducing the application of traditional fertilizers by 20%. For corns grown in castano-cinnamon soil and dark brown soil, the application of the new fly ash-based soil conditioner for three consecutive years has steadily increased the yield by more than 10%. The yield of wheat planted in castano-cinnamon soil also increased by 15%. Additionally, considering that heavy metals (HMs) contained in the fly ash-based soil conditioner may cause environmental contamination, this paper calculated and analyzed the bio-concentration factor (BCF) and the translocation factor (TF) of Cr, As, Cd, Hg and Pb in the corn experimental fields. The results showed that the five heavy metals were not significantly enriched in various parts of the corn stalk after application of the soil conditioner, and there was temporarily no environmental risk in terms of returning straws to the field or raising livestock.