First, let’s review why pyrolysis presents exciting possibilities as an effective manure management practice. As a storage form of manure, biochar is much lighter and significantly more stable compared to raw manure. This makes it easy to move and provides long-term storage possibilities. The stability factor also presents the exciting potential to largely avoid the nutrient runoff issues that commonly happen when raw manure is applied to fields, through applying biochar instead. Beyond fertilizer and soil amendment uses, manure biochar has other interesting possibilities. Because of its nutrient content, it’s being added to feed in some parts of the world. Lastly, its high porosity and absorptive qualities make it attractive as an addition to poultry bedding, with ammonia emissions presenting long-term bird and farmer welfare challenges in the barn.
But it’s still early days, and there are a number of pieces that need putting in place before we’ll see widespread pyrolysis in North America. One requirement is for farmers to understand and be comfortable with biochar – and that means good data.
Research so far
According to Joseph Sanford of the University of Wisconsin-Platteville, the bulk of the biochar research has been focused on laboratory or greenhouse settings. “These are useful, but may not be transferable to the real-world conditions,” he explains. “Most producers are not going to invest in something on a large scale without field-based findings. Most [in-field studies] are just starting.”
Of the studies Sanford knows about, results indicate field applications of biochar produce variable yield responses to various crops. Further studies are needed, in Sanford’s view, to tease out the effects of different soil types and regional climate differences across various crops, various biochars and at different rates of application. There’s also the need, says Sanford, to take a close look at the economic benefits of these applications within traditional crop systems (e.g. corn, soybean, alfalfa) in relation to yield and other factors that impact a farm’s bottom line.
The U.S. Biochar Initiative (USBI) also recognizes the need for comprehensive and detailed studies. The organization is working with scientists at Washington State University on large-scale trials of biochar and biochar-enhanced fertilizers on commercial farms, and also plans to support research into using biochar in greenhouse growing media. Starting this fall, USBI will host information sessions in conjunction with American Farmland Trust to build knowledge among interested agricultural professionals.
A close look at costs
As is typically the case with emerging technologies and products, costs are very high at the start. Sanford notes if manure biochar is applied at a rate of 1 ton/acre (research shows more would be needed for appropriate crop response), the cost would likely between USD $500 and $2000/ac. Yes, he notes applying biochar may boost long-term soil carbon reserves, which can boost crop yield and provide other crop benefits. Yes, it has the potential to decrease nitrogen leaching compared to raw manure, which may save farmers money. But at the same time, Sanford is blunt. If applying biochar doesn’t provide significant ROI via decreased fertilizer inputs or increased yields, he says “I do not think we will see adoption without other incentives or cost-sharing programs.”
As with manure digesters, making biochar from manure on the farm would involve significant capital and operational costs. Sandford therefore doesn’t foresee it being something farmers would undertake for their own use alone. However, it could be feasible on a large scale as a way to move manure/nutrients outside of a spreadable area, maybe with one dairy farm for example making biochar from its own excess manure and excess from several other nearby farms and shipping some of the biochar to other regions.
Let’s go deeper into what biochar production on a farm would look like, with Mahmoud Sharara of North Carolina State University. He explains biochar production systems, particularly ones using manure solids as feedstock, involve complex feeding, cleaning and heating components. To ensure proper operation, trained staff would need dedicated time to carry out operations and maintenance. These sorts of systems, which involve a learning curve and experience, are hard to staff because there is already a shortage of farm labor, says Sharara, and there may be a seasonal nature to this work as well. “Also, the availability of prompt assistance for repairs and parts replacement are typically missing with new technologies,” he says. “This can lead to longer down-times for the equipment that both reduce productivity and discourage sustained use and wider adoption.”
So, while Sharara acknowledges cost-share programs and funding to cover capital investment may be available in future, he believes the high capital costs and specific labor requirements mean only a few farms could afford the infrastructure, and also have the required livestock and workforce to make biochar from manure.
Part 1 looked at two companies capturing heat from the biochar-making process to save money drying manure. However, Sharara says for this to work on a farm, operational flexibility would have to be present. “For example, variability in manure solids properties, including water content, bedding type and soil contamination, may interrupt feeding and drying step,” he explains. “This may reduce overall energy efficiency and increase drying and conversion costs. That is not to discourage pursuing these energy-efficient strategies, but to ensure they are designed to be robust and built with an eye for conditions of on-farm manure management.”
Building markets
At the same time costs must be managed with producing any new product, the market for it must be developed. Indeed, the market for biochar is the biggest economic challenge in the view of Dr. Rebecca Larson at University of Wisconsin-Madison. “While biochar has a lot of buzz, actual sales and the price of the biochar are still evolving and those implementing the systems would have to do the work to develop the market for their products,” she notes.
To build a customer base for biochar as a fertilizer and soil amendment, USBI is hiring a director of agricultural markets. And in Minnesota in mid-September, it’s also hosting the 2025 North American Biochar Conference as well – where a key workshop is laser focused on a critical market issue, the development of an American National Standard for biochar analysis. Standards, in the view of USBI, are the linchpin in creating the trust in the effectiveness of biochar products.
Jeff Porter, technical consultant at Newtrient (see Part 1), is of the same view. “Part of the marketing is that the properties of the biochar also have to be determined, so that farmer-customers can work biochar effectively into their fertility plans,” he notes. “Customers will need to know exactly what dairy manure/digestate biochar contains and to have consistency. I think standards will eventually be in place to address this concern.”
According to USBI, two sets of standards have already been developed, one by the International Biochar Initiative and one by Carbon Standards International. However, in a recent newsletter, USBI reports that the former “were never designed with commercial laboratories in mind,” and the latter “are based on German laboratory standards and therefore are a no-go for most laboratories in North America.” As such, very few labs in North America offer analysis for biochar.”
For Larson, she’s focused on the idea of making cheaper but effective biochar products. “Say for example you can use the biochar in specific purposes to replace or reduce activated carbon, or in digesters to reduce hydrogen sulfide gas,” she says. “Alternative potential applications could greatly increase the value of biochar, making system payback more feasible.”
Like Sanford, Larson wants more info, from the impact of biochar applications on crop yield and more over time, the potential of higher-value markets, replacing costly off-farm purchases with biochar, and so on, “to be able to really model the impact of integrating manure pyrolysis systems to determine if the financial benefits can be significant enough.”
One big issue, she adds, is all biochar is different, with the characteristics depending on feedstock (including potential pre-conditioning), pyrolysis settings (temperature, duration, etc.) and possible post-processing activities. “We are just beginning to explore all these impacts,” Larson says. “It’s critical to continue to evaluate all the various biochars and vary the conditions, for example blending feedstock or altering temperature, to understand if we can create biochars with greater value for many end uses. This will take time and resources, but I am hoping that the current buzz around biochar can sustain that interest as it has the potential to really improve sustainability.”
Ammonia, haulage and more
Besides the reduction in nutrient leaching that should be significantly achievable with applying biochar, ammonia emissions from lagoons are a concern. Sanford reports some small-scale studies have shown biochar can provide some help in reducing them. Spreading them on the lagoon surface is one idea. “Some areas of the country are more concerned than others about ammonia emissions, but it might be a tool in the toolbox.” Still, he says, larger-scale studies need to be done to assure these benefits are transferable to real-world situations.” •
