Biochar Trials with American Farmland Trust
White Feather Farm, New York
Part One: Set Up, Sourcing Application, and Planting
August 14, 2024 | Written by Bill Hilgendorf
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In February we kicked off our 5 year biochar field trial with American Farmland Trust (AFT) and Cornell University. The trial is part of a national field trial that AFT is heading up with NRCS called Breaking Down Barriers to Biochar Adoption on Farms from Coast to Coast. It is a “Soil Health Demonstration Trial” that will quantify the climate, environmental, social, and economic impacts of biochar applications on working farms. Since we are the first farm in the county to get biochar in the ground and beds planted for this trial, it has been an incredible learning experience for the whole team.
We are fortunate to have a local supply of woody biomass-based biochar just next door courtesy of NY Carbon, which utilizes wood waste from a milling operation on a property adjacent to White Feather Farm.
The process started with crushing the biochar to a consistent particle size and then mixing it with compost from our local supplier Hudson Valley Organics in Old Chatham NY.
Hudson Valley Organics operates a compost screening machine and was the location where we mixed biochar and compost to start the inoculation process. Inoculation is a critical part of the biochar application, since biochar acts like a dry sponge soaking up nutrients, minerals and microorganisms it is very important to add it to the soil pre-charged so that the biochar does not suck up these elements from the soil that you are planting in.
They will then be available later when most needed. While you can apply raw biochar to your soil, you may need to plan on the potential of a dip in productivity for a season while biochar charges up. Adding before cover cropping is a good time to add raw biochar if you don’t have time to pre- charge it. Biochar can also be inoculated easily with a compost tea or simply by co-composting with it, by just adding to your compost pile. This is especially effective as the compost heats up with all the activity, the biochar is rapidly and thoroughly filled with microbes.
Hudson Valley Organics Compost Screening Machine
Plot Design
WFF worked collaboratively with American Farmland Trust to develop the study plot design. It incorporates three different bed treatments, a control, Section C which is just our standard compost application, and two biochar compost blends. We are also including a buffer bed on each end of the trial area. As shown we utilize a 30” bed system and each bed is 60’ long.
Earth Optics
Part of the trial includes broad soil carbon accounting. This was accomplished with a scanning system developed and operated by Earth Optics. A sensor on the front sends radio waves into the ground to gather information about the soil charactoristics. It’s a pretty cool rig and definitely the future of soil testing for carbon sequestration! One of the goals for Earth Optics is to be able to show additional carbon added through farming practices so farmers can have the opportunity to eventually sell sequestration credits or CORC’s on the voluntary carbon market and get paid for their work building soil and taking carbon out of the atmosphere.
Soil Sampling
We also facilitated extensive manual soil sampling which included the Cornell Comprehensive Assessment of Soil Health to establish a baseline. Everything came back pretty good, but there was an opportunity to address some soil compaction with biochar as well as excessive phosphorus
Our standard practice in bed preparation is to use a broadfork to open up and aerate the soil prior to compost application. This method causes minimal disturbance to the existing soil ecosystem while reducing compaction.
Many hands make light work. Beds are amended and ready to rake out.
Seen above, the beds are all prepped and we have the three treatments ready to apply.
After we raked out the beds we used the Tilther to integrate the new biochar compost into the existing soil in the beds.
We used 5 gallon buckets to measure out our application rate. Each trial section got 25 gallons of compost or compost biochar mix.
Always working to reduce our plastic use on the farm we are experimenting with paper mulch weed blocker paper. We will see how it compares to the landscape fabric we usually use on beds.
All planned and ready to GROW!
It has been a wonderful experience working with the team at AFT so far. There is so much important data to be collected, we are looking forward to observing the progress with our winter squash planings as they grow and fruit. The experience of going through all the processes first hand from making the biochar and reducing the particle size, and mixing it with the compost and applying it to the beds has really led to a comprehensive understanding of all the factors that need to be considered when planning an experiment like this.
Up next we will report back what we learned from the first growing season of the trial. Stay tuned!
Close Up Examples of the Three Mixes
50% Biochar 50% Compost
25% Biochar 75% Compost
100% Compost
Part Two: Growing, Harvesting, and Measuring Yields
October 10, 2024 | Written by Bill Hilgendorf
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Wow, it feels like the growing season flew by! After a slow start, which included a dry spell and troubleshooting some issues with the paper mulch (we should have bought the 48-inch wide roll to secure it properly with the wood chips) and a blockage in our irrigation system, the squash plants really took off.
Although many plants developed at similar rates, it was quite interesting that, on some occasions, two plants right next to each other in the same plot — theoretically receiving the same water, sunlight, and nutrients — grew at vastly different rates. In this case, pest activity may have caused the disparity, but it’s a reminder that even when you provide consistent conditions, you can’t control all the variables in an open-field experiment.
By the second week of August, which was about eight weeks after planting, many of the plants were showing significant fruit development. The progress was noticeable, with several plants beginning to bear large squash, marking an important milestone in the growing season.
By mid-August, the squash began turning yellow, signaling that it was nearing harvest time. The paper mulch and woodchips did an impressive job of suppressing weeds. In the left side of this photo, you can see the rows where we used traditional plastic landscape fabric, with uncovered paths now full of weeds. We will definitely use the paper mulch and woodchips again when we plant next spring.
As microplastics and PFAS (per- and polyfluoroalkyl substances) become a growing concern, even in organic-certified products, it's crucial that we continue testing and innovating with new solutions to mitigate these threats. Although we aren’t testing for these contaminants in this trial, new studies are showing great promise in biochar’s ability to absorb harmful substances and lock them away, making them unavailable for plant uptake. It will be exciting to see the results of these studies as they emerge.
We did our first harvest the last week of August and furnished up our final harvest the last week of September. Sometimes tracking the vines all the way back to the original subplot was quite a challenge.
After collecting all the squash from each subplot, we measured and weighed them to gather yield data for the trial. We are still analyzing the numbers, but overall, it was by far the best squash harvest we've had in the last couple of years.
Over the next month, we’ll begin closing down the beds, preparing them for winter, and start planning what to plant next spring. The paper weed block will be left in place over the winter to naturally break down, and in the spring, we’ll incorporate it into the soil as we prepare the beds for the next planting.
While the final decision is still up in the air, the conversation is leaning toward planting hot peppers. Stay tuned for year two of our AFT biochar field trial—it’s shaping up to be exciting!
Aaron Ristow and I checking out the biochar excited to wrap up a successful season.
