Biochar: Ancient Technology Enhances On-Farm Water Quality

The old saying, “there is nothing new under the sun”, holds true with the rediscovery and renewed interest in the benefits of biochar.  Biochar is a carbon-rich product created by roasting organic materials in an oxygen- limited environment, much like the process used to make charcoal. In the Amazon basin, thousands of years ago, indigenous farmers would add biochar to their nutrient poor tropical soils creating terra preta, or dark earth, and theses soils have remained highly fertile to this very day.  With today’s technology, the creation of biochar can divert biomass waste streams into the valuable product that can provide many social, environmental, and economic benefits. Byproducts made of organic matter like wood chips, green waste, grain hulls, and manure are upcycled into biochar in tightly controlled commercial systems which can be sold and integrated into agricultural applications, including agriculture.

As research on biochar continues to abound from around the world, there is a renewed interest in how this very simple process, yet complex product, can help purify water, restore degraded soils, remediate contaminated landscapes, and increase productivity of agriculture and nursery operations. Ecotone is actively testing out its application in our region.  One of the major benefits of biochar is it does not decompose as compost does, so it is able to last hundreds if not thousands of years and maintain soil health and productivity. Interestingly, the combination of even a small amount of high-quality compost with biochar has been found to enhance the soil microbial health and promote soil micropore development. This small addition could be a huge boon not only to the many farmers we work with in our restoration projects, but also in the urban landscapes with highly compacted soils where we work. 

The Brandywine Conservancy, a land conservation organization with a special focus on clean water, sustainable agriculture, and habitat protection, reached out to Ecotone in Spring 2020 to replace a failing infiltration basin on Lofting Farm in West Grove, Pennsylvania. With our mutual interest in applying biochar to agricultural, stormwater, and soil enhancement best management practices (BMPs), this project was a great way to help the Brandywine Conservancy begin trialing biochar as part of their BMP installations.  After surveying the site conditions, we decided on a design that would upgrade the basin to a denitrifying woodchip bioreactor swale enhanced with biochar.

The project’s goal was to capture wash water from two barns and a small, paved area between the barns. We installed the swale, a trench two feet deep, two feet wide, and approximately 150 feet long, lined it with geotextile and included a perforated pipe wrapped in filter sock to complete the infiltration system. The trench was then filled with a mixture of 85 % green woodchips and 15% biochar, and the surrounding area was stabilized and re-seeded with native meadow species. At the inlet an open top concrete box was formed up to allow for sediment settlement and to make for easy cleaning while at the lower end, we constructed a stone outlet seep. Ecotone had the project fully installed in just under three days. 

As the enthusiasm for biochar continues to grow in the mid-Atlantic region, more projects focusing on water quality are being designed to include biochar, and Ecotone is excited to be at the forefront of these innovative practices. Amending soils and other engineered media with biochar enhances the benefits of BMPs and can improve fertilizer management and productivity of agricultural lands.  The National Resources Conservation Service (NRCS) is recognizing the potential of biochar with the recent development of the Soil Carbon Amendment Practice. We look forward to integrating biochar into similar projects in the future as well as expanding its use in our nursery operations and to improving urban soils and stormwater management systems. Stay tuned for more on biochar!


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