Cover crop application on dredged sediments increases corn yield through microorganism-associated enzyme-driven nutrient mineralization.

Abstract

Abstract Background & Aims Common strategies to mitigate soil degradation of agricultural soils include cover crop application and soil amendment addition. Applying dredged sediments as a soil amendment is gaining popularity since they often provide benefits other amendments lack; however, their use with cover crops is largely unexplored. To understand how cover crop use changes the restorative properties of dredged sediments, we assessed soil physical and chemical properties, enzymatic activities, and corn yield for plots of dredged sediments with and without a cover crop.Methods We assessed soil texture, bulk density, water content, pH, nitrogen, phosphorus, cation exchange capacity, calcium, magnesium, potassium and organic matter content, as well as alkaline phosphatase, β-glucosidase, leucine aminopeptidase, peroxidase, polyphenol oxidase and urease enzyme activities and crop responses and yields in manipulated dredged sediments with and without a cover crop over three collection periods: pre-cover crop, post-cover crop, and post-harvest.Results Cover crop application on dredged sediments increased corn yields by ~ 24% when compared to dredged sediments alone. Increases in corn yield were driven by changes in nutrient mineralization, specifically within the nitrogen cycle. The physical and chemical properties of dredged sediments remained unchanged regardless of cover crop application.Conclusion Our results suggest that when cover crops are applied to dredged sediments, crop yield increased through microorganism-driven nutrient mineralization. However, the physical and chemical environment remained optimal for corn growth within dredged sediments, regardless of cover crop application. This research is a vital step into understanding the use of dredged sediments in agricultural soil systems.