If you’ve ever stepped foot on a dairy farm, you know the smell of cow manure comes with the territory. Farmers deal with the challenges of disposing of the waste on a daily basis, but a sustainable fertilizing trend could be a modern-day solution.
Smaller farms with only a few dozen cows may have simpler solutions for manure that don't pose environmental hazards. But farms with more than 200 cows face more challenges. They sometimes have to find or rent fields simply to spread the manure, or store it in lagoons. Mishandled, the manure could dump excess nutrients into aquifers or other water sources.
However, heat the manure to 700 to 1,200 degrees fahrenheit without oxygen, and one can create biochar fertilizer. The process is known as pyrolysis, which is very different from incineration -- instead of producing only ash and smoke, pyrolysis produces nutrient-rich liquid and solid residue.
Leilah Krounbi, a doctoral student researching biochar at Cornell University, has grown crops with nutrient-rich manure biochar, including radishes and tomatoes. By treating the biochar to enrich it with nitrogen, Krounbi’s crops saw up to 35% greater plant growth.
Krounbi said interest in biochar stems from three interests:
*Generating energy using pyrolysis.
*Finding a solution for waste biomass from forests, farms, and even urban wastes.
*Creating alternative soil amendments to boost soil fertility.
“It seems that the idea of enriching biochars with nutrients for use as alternative nutrient fertilizers came later, as people understood more about the chemistry of these materials,” Krounbi said. “Pyrolysis of high-nutrient feedstocks, such as manures, seems the latest development.”
Biochar fertilizing could decrease the amount of manure to dispose of on farms, and protect natural resources in the area. Runoff from manure into surface waters can deplete oxygen for fish and other water life, Krounbi said, and nitrogen from the manure could pollute groundwater and pose health and safety hazards.
But biochar doesn’t have to be made with cow manure, nor is it simply a fertilizer.
In the early 2010s, Main Street Farms in Cortland partnered with Cornell University to do a biochar trial using woodchips, said Adrianne Traub, who worked at the farm.
“It was a fairly clean production of energy for us because we were using a lot of energy to heat our hydroponics greenhouse,” said Traub, now a project coordinator with Seven Valleys Health Coalition’s USDA local food promotion program. “So instead of using oil or natural gas, we were able to use this to produce heat and provide seasonal extension for growing earlier in the spring and later into the fall.”
The wood chips were released into the combustion chamber, where they would burn at such a high temperature, little smoke was created.
“After the combustion chamber, there was a fan that pushed that hot air into the greenhouse, and a vent that led through a hole in the top of the greenhouse to release the excess smoke,” Traub said.
Main Street Farms’ greenhouse used an early version of biochar technology that still needed tweaking, but the results during its trial farming season were notable.
“This is a viable, new agricultural technology,” Traub said. “I think with the increase in efficiency and improvement in design over the years, it could be a huge help to farmers both with heat production and for sustainable soil amendments to increase soil quality.”
Biochar fertilizer has been a passionate topic for Assembly Member Anna Kelles (D-Ithaca) for years.
“It is 100% a solution to increasing the carbon sequestration of soil, increasing the quality of soil, decreasing the need for fertilizing and potentially decreasing the need of some pesticides,” Kelles said Saturday during a legislative tour of Cortland County farms.
Kelles grew up down the road from a Tompkins County farm, later pursuing degrees in biology, environmental studies and nutritional epidemiology. She now chairs the Assembly subcommittee on agricultural production and technology.
Kelles co-sponsored a bill to create a program to help farmers improve the health of the soil and simultaneously reduce the effect of farming on climate change — a bill that has passed both houses but needs to be reconciled. She said biochar fertilizer could be a part of that.
“If you’re on a farm, you could use excess manure so you don’t have to buy extra fields to spread it in the fields -- instead, get a pyrolysis unit, make the biochar and till it back into the land,” Kelles said.
The downside is there is still more research to be done regarding the labor behind running different pyrolysis units, how to integrate it into farms and what the cost would be for individual farmers.
Centralized pyrolysis facilities would likely be more efficient than smaller farmers creating biochar on their own, Krounbi said. “It will also be cheaper for farmers, not requiring each farmer to invest in their own kilns, but rather share the cost across a community.”
“I want my colleagues to understand it more, and for all of us to be talking about it more, so that we can start to explore pilot funding, working with farms and working out the kinks to integrate it,” Kelles said. “The benefits are too large to ignore.”