Making Woodchip Bioreactors More Accessible by Expanding Woodchip Source Materials and Increasing Supply Chain Capacity

Issue

Iowa’s agricultural productivity relies heavily on nitrogen fertilizers and subsurface tile drainage systems, which accelerate nitrate-nitrogen (NO₃-N) runoff into surface waters. This contributes to water quality degradation, increased treatment costs and hypoxic zones in the Gulf of Mexico. Although denitrifying bioreactors are effective at reducing NO₃-N, their adoption is limited due to high costs and low awareness.

Objective

This project aims to:

1. evaluate alternative, low-cost woodchip sources for use in denitrifying bioreactors to reduce implementation costs, and
2. expand education and outreach efforts to improve understanding and adoption of edge-of-field conservation practices among farmers, landowners and supply chain stakeholders.

Approach

Researchers will assess the hydraulic properties of various woodchip sizes and processing methods to determine their suitability for bioreactor media, focusing on saturated hydraulic conductivity (Ksat). Preliminary findings suggest that smaller woodchips may meet design standards while reducing waste and cost. Concurrently, the team will develop training and outreach programs targeting farmers, contractors, and woodchip suppliers to bridge knowledge gaps and support workforce development. This dual approach will enhance bioreactor performance, reduce costs and increase adoption across Iowa.