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The need to maintain healthy agricultural soils has never been greater as we face the challenges of climate change and feeding an expanding human population.
At Cornell, sustainability is a guiding principal across campus. Education, research, and public activities all implement sustainable practices. It is also an integral part of Cornell’s Climate Action Plan, which calls for reaching carbon neutrality by 2035. Cornell is exploring new options for their organic wastes, and finding solutions using slow pyrolysis to create biochar, and composting. Researchers are studying the benefits of using biochar and compost as soil amendments. Both biochar and compost can help renew depleted soils while diverting waste from landfills. Together, these practices fight food insecurity.
According to the Environmental Protection Agency (EPA), solid waste landfills are the third largest source of human-related methane in the United States. Methane is a potent greenhouse gas (GHG) and emissions can be cut by reducing materials sent to landfills. Diverting waste to biochar and compost may reduce overall methane production. Biochar and compost can have the added benefit of storing carbon.
“Soil is fundamental to humans and we’re losing this stuff. Char is a way of reinvigorating depleted soils, of preserving or improving existing soils, managing or sustaining agricultural yields in the face of not so great climatic conditions. Char can improve nutrient use efficiency, water holding capacity of the soil… this is moving forward.”
- Akio Enders, Cornell University
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This Bioenergy and Biochar Facility at Cornell University is home to the largest pyrolysis unit of its kind in the nation. It was built in 2016 with a gift to the Atkinson Center for a Sustainable Future. Cornell researchers are studying biochar, a charcoal made from plant biomass using pyrolysis. In pyrolysis, the plant matter is heated and decomposed without oxygen. The solid biochar that remains is rich in carbon and can be used as a soil amendment. Researchers are looking at how biochar might help to improve food security and mitigate climate change. Through this process, wastes are being turned into a valuable agricultural commodity.
Terra Preta soils of the Amazon were created by the people who lived in the Brazilian region long ago. Cornell researchers, inspired by Terra Preta soils, are using biochar to replicate these fertile conditions. Follow this link to hear Cornell's Dr. Johannes Lehmann describe his research with Terra Preta soils and biochar. Or check out this science brief to learn more about Terra Preta soils and how biochar can improve soil fertility and sequester carbon.
Researchers at Cornell are studying the benefits of biochar for the environment. Here are four reasons why farmers, home owners, cities, and businesses might want to consider biochar: improved soils, waste management, energy production, and carbon storage. By improving soils, reducing waste, and storing carbon, biochar may help users adapt to or mitigate climate change.
Akio Enders, Cornell University Research Support Specialist, explains how biochar is a win-win for both farmers and the environment. Biochar is produced from waste products, creates renewable energy, sequesters (stores) carbon, and can improve crop yields. Pyrolysis and biochar will not completely fix the challenges posed by climate change. However, they are tools that can be used successfully in some places. Cornell's Climate Action Plan lists slow pyrolysis as one way to capitalize on the campus waste streams by generating renewable energy. Land application of biochar may be an effective method for long-term capture and sequestration of carbon and help further offset emissions.
Slow pyrolysis heats and decomposes biomass in the absence of oxygen. The liquids and gases that are produced can be used for energy. The biochar solids are a byproduct that can be used to improve soil fertility. This process results in approximately 50 percent bioenergy and 50 percent biochar. Fast pyrolysis can also be used, but less biochar is produced while the amount of liquid biofuel production increases. Pyrolysis gases and liquids can be captured to create electricity, bio-oils, hydrogen gas, ethanol, methane, and other coproducts that can be used by different industries.
Akio Enders, Cornell University Research Support Specialist, introduces us to the process of pyrolysis. Enders is from Cornell University's Department of Soil and Crop Sciences in the Soil Fertility Management & Soil Biogeochemistry Program.
Akio Enders, Cornell University Research Support Specialist, explains the pyrolysis process. Heating conditions can be precisely controlled in this pyrolysis kiln, which can convert up to 50 kg of waste an hour. This allows the researchers to quickly test the efficiency of a variety of biochar feedstocks. So far, the research group has tested materials including wood chips, food scraps, crop residues such as corn stalks, animal manures, and wastewater. Using waste biomass as feedstock is emphasized. The goal is to find feedstocks that can be used as safe and effective soil additives while also producing energy and reducing greenhouse gas emissions.
Some benefits of using biochar to improve soils have been documented, but few large-scale farmers have adopted its use. This is partly due to the lack of large-scale research to test biochar product quality and consistency. With this kiln, Cornell plans to address this concern. The best uses of biochar in both large agricultural operations and small farming communities in developing countries will be studied. In this video, Akio Enders, Research Support Specialist, tells us how biochar can help farmers improve their soils and crop yields. USDA's Agricultural Research Service is also examining how biochar impacts soil quality and crop productivity. Research results show some benefits, but benefits are not present in all soils.
Biochar can affect soil fertility by helping soils retain plant nutrients and water. Because it persists in soils, it could provide longer-term benefits than some other types of organic materials, such as compost. Biochar has been tested in different soil conditions with varying results. In some soils, biochar may significantly affect the amount of beneficial plant symbionts and crop pathogens.
Rural homes in most developing countries depend on woody biomass for energy. This causes indoor air pollution that is responsible for 1.5 million deaths a year. Cornell researchers are designing a clean-burning pyrolysis cookstove to help address this problem. Cookstoves based on pyrolysis can burn many types of biomass, which can help reduce the impacts of gathering wood fuel. Cleaner-burning stoves will reduce harmful health effects of kitchen smoke in developing countries. In addition, the production of biochar from these cookstoves could aid in biochar adoption. Sub-Saharan Africa has one of the highest rates of food insecurity due to insufficient crop yields. The use of biochar on agricultural soils here could help to improve nutrients, plant-microbe interactions, and water use efficiency, leading to increased yields.
Researchers at Cornell are also building a low-temperature pyrolysis kiln for use in a village setting in Kenya. The bioenergy and biochar produced would help the local village and people nearby. The biofuels could be used as a transportation fuel and help those in rural areas get produce and crops to the villages where they could sell them in the markets. The biochar could be applied to degraded and acidic tropical soils where it could provide many benefits. Biochar can help to sustain crop yields, minimize soil degradation, and retain nutrients applied to the soil. The pyrolysis kiln could increase income and help to feed the village and surrounding communities, while providing a source of clean energy.
Cornell University’s compost site is operated by their Farm Services. It was started in 1992 to manage manure from livestock in Cornell’s care. Manure and bedding from the veterinary hospital, the Animal Science's teaching barn, poultry facilities, and horse barn are brought here. In 1998, Cornell dining halls started composting food scraps. Each year, 4,000 tons of animal bedding and manure, 300 tons of plant debris, and 800 tons of food scraps are composted. It takes 6 to 9 months to turn organic waste into compost. Most of the compost is then spread on Cornell's nearby agricultural fields or on campus. Some is sold to the public or donated to local charitable groups. This compost facility provides a product that can improve the soil of the 1000+ acres owned by the university. The facility is also used for research and to demonstrate compost production.
Water and nutrient runoff from the compost facility is captured in two large collection ponds. During dry periods, the water can be used to moisten the compost piles. Alternatively, the water can be used to irrigate pastureland that serves as a biofilter that takes up the water and nutrients. To protect local water quality, careful planning is needed when deciding where to locate a compost site, how to design it, and how it will be managed. Outdoor facilities should be constructed on a pad. This not only protects water quality, it also improves access to the piles during all weather conditions.
Each retail dining facility at Cornell has a “separation station” so students can sort their trash, recycling, and compost. Food scraps from the compost bin are then sent to a pulper and dewatered before being picked up by Cornell’s Farm Services. One of the biggest challenges is raising student awareness and getting them to separate their trash. Two of the innovation goals listed in Cornell's Climate Action Plan are expanding composting and campus climate literacy. Once the benefits of the current program are realized, composting will be expanded to residence halls and special events on campus. Composting, as a form of experiential learning, is also one of the tools being used to help educate those on campus about sustainable solutions for climate change.
Adding compost can improve soil quality. Compost helps to loosen the soil, allowing better air and water movement and improved root growth. Compost also holds moisture and nutrients while allowing excess water to drain away. The Cornell Waste Management Institute has identified seven general compost use categories for soils. Categories range from agricultural soil improvement to erosion control. To find out if your soil could benefit from adding compost, check out the Comprehensive Assessment of Soil Health (CASH). CASH is a test developed by the Cornell Soil Health Testing Laboratory to quantify biological and physical characteristics of soil. It also provides indicators and management strategies for improving soil health.
According to the Environmental Protection Agency (EPA), municipal solid waste landfills in the United States are the third largest source of human-related methane. Methane makes up about 10 percent of U.S. greenhouse gas emissions, but each molecule has an impact that is more than 25 times that of carbon dioxide. Diverting organic wastes from landfills is one way to reduce this emission source. Composting emits C02 instead of methane, and when compost is added to soils, carbon is sequestered. This means composting can help mitigate climate change. When compost is used to increase soil organic matter, soil drainage and moisture holding capacity are also improved. These changes can make soils more resilient to changes in climate. Visit Cornell’s Climate Smart Farming for more resources and tools to help you become more sustainable. Tools can help you increase productivity and income, reduce emissions, be more energy efficient, and improve resilience to weather and climate variability.
At this site, waste is piled into heaps called windrows that are the length of a football field and 7 feet tall. From April to November, the compost piles are turned each week. Different equipment can be used to turn piles, but here a specialized compost turner straddles each row in order to do the job. When making and maintaining compost, mixing and aerating the organic matter helps to speed up the process and regulate moisture levels. The ideal moisture content is 40-60%. If compost is too wet, there may not be enough oxygen for the microorganisms to function. If too dry, beneficial organisms cannot repopulate, ammonia gas is lost, and molds may develop. The windrow shape allows oxygen to easily move through the pile while retaining the optimum amount of heat. Regularly turning the piles allows all of the materials to be exposed to the high temperatures in the center of the pile. Turning the compost too often, however, can dry it out.
Compost is produced when organic waste decomposes to a uniform and stable finished product. Microorganisms work at elevated temperatures in the presence of oxygen and moisture to break down the organic matter. The process has three phases.
(1) Mesophilic, or warm phase, lasts a couple of days at moderate temperatures (up to 110 °F).
(2) Thermophilic, or hot phase, has high temperatures (110 to 130 °F) that can last anywhere from several days to several months.
(3) Maturation phase, or curing phase, is a cooling that lasts several months.
Different kinds of microorganisms (including bacteria, fungi, protozoa, and rotifers) are active during the various phases.
For all of the ins and outs of composting, check out the resources available from the Cornell Waste Management Institute. Whether you are a home composter or large-scale operator, here you will find fact sheets, calculation tools, reports, and more to help you with your composting.
Compost facilities and transfer stations are located all over New York State and surrounding areas. Some locations are also education and demonstration sites where you can learn more about composting. Check out the Cornell Waste Management Institute’s interactive map to find one near you. Facilities are managed by farms and other private owners, schools and universities, nonprofit groups, and government organizations.