Developing more efficient agricultural practices is critical to support a growing global human population. Current large-scale agricultural practices lead to severe soil degradation. To alleviate soil degradation, cover crops, or crops planted in off seasons, are increasingly common components in Midwestern agricultural practices. Despite their benefits, soil amendments are often used in conjunction with cover crops to further improve soil properties. The use of dredged sediments as a soil amendment is increasing worldwide but little is known about mechanisms driving these soil improvements. To fill this knowledge gap, we experimentally manipulated two agricultural fields made of 100% dredged sediments in Toledo, Ohio. We planted one field with a common cover crop, winter rye (Lolium perenne) and left one field fallow through winter. Throughout the following growing season, we measured ten corn plants from each plot for relative growth rate. After the growing season, we determined above and below ground biomass and final yields. To asses soil property shifts, we performed physiochemical and biological assays on sediment samples collected from three time periods: before cover crop planting, after cover crop life cycle, and after final corn harvest. We analyzed these data using univariate and multivariate statistics to establish mechanistic changes.
Results/Conclusions
Applying winter rye to dredged sediment fields increased corn crop yield and alleviated soil degradation. There were no significant differences in above (P = 0.4587) and below ground corn biomass (P = 0.9578) between cover crop and non-cover crop fields. However, application of winter rye resulted in corn yields 20% greater than the non-cover crop field (F1,22 = 0.6729, P = 0.0012). Cover crop application also eliminated differences in pH between the fields, making the sediments more basic (P < 0.0001) but had no impact on sand, silt or clay content between the plots (P = 0.136, P = 0.089, P = 0.360,). These data suggest that dredged sediments are suitable for agricultural soil amendment when used in combination with a cover crop. This work represents an important component for understanding the potential agricultural benefits of cover crop use in conjunction with dredged material. This research will provide much needed improvements to agricultural practices worldwide, as demands on agricultural systems continue to increase.