Biochar Leachate Evaluation


To examine the leachate over time from a selected range of biochar and greenhouse media blends to assess nutrient holding and loss over time, and thus potential impact on plant growth and environment.


Walker Industries Inc. is a diverse, Ontario-based company with an environmental division, Walker Environmental Group Inc. (WEG), that specializes in waste management and resource recovery. One of the areas of focus for WEG is controlled pyrolysis of high-carbon waste, where they aim to divert this waste from the landfill, generate a valuable blend of gases, and produce a useful solid by-product. This solid by-product is called biochar, which has been proven to be beneficial to agricultural operations by capturing nutrients in the soil and providing these nutrients to the crop.

Before biochar is to be used successfully as a soilless greenhouse media enhancement, its blend rate must first be determined. The risk of excess biochar blended in media may make nutrients less available as roots will be unable to uptake nutrients. If too little biochar is blended with media, there may be insignificant nutrient retention and thus limited reduction of nutrients in leachate. 


The Horticultural & Environmental Sciences Innovation Centre (HESIC) team at Niagara College (NC) created a matrix of biochar and peat moss/perlite blend ratios, obtained by Walker Environmental Group Inc. from Gro-BarkĀ®, to examine the nutrient content of leachate over time and whether nutrient content within the leachate was affected by the rate of biochar. This study found that the amendment of Gro-BarkĀ® media with biochar increased media cation exchange capacity (CEC) and decreased nutrient loss due to leaching. A subsequent study involving a plant growth trial with biochar-amended media will be performed.

Funding: This project is being funded in part by the Niagara College-led Greenhouse Technology Network (GTN), through the Federal Economic Development Agency for Southern Ontario (FedDev Ontario).