Amending woodchip bioreactors with corncobs reduces nitrogen removal cost.

Woodchip denitrification bioreactors are an effective agricultural practice to reduce nitrogen (N) export from subsurface drainage via the conversion of nitrate (NO) to nitrogen gas (N), but there are challenges associated with limited woodchip supplies and increasing prices. Previous lab studies indicate that corncobs could be a promising woodchip alternative from the perspectives of N removal rate and cost. This field study aimed to provide early performance and cost assessment of denitrification bioreactors with two woodchip-corncob treatments.