Progress report for LNE22-452R
Project Information
According to previous scientific studies, biochar’s vast surface area, porosity, and durability provide habitat for beneficial microbes, increase soil water-holding capacity, and enhance soil health and carbon storage (Brewer, et al., 2014; Yao, et al., 2012). Because biochar is relatively easy to produce and can utilize local biomass waste streams, it has the potential of being a widely available renewable resource. It has been studied in annual systems, but rarely in the perennial context of tree crops. Increased interest in regenerative farming and agroforestry to bolster the viability of agriculture in the region and to provide ecological benefits require new data to guide application and usage. Farmers are interested in biochar but have not widely adopted the practice due to a lack of practical knowledge on optimal management. This project is assessing the effects of five treatments of biochar, compost, micronutrients, minerals, and microbes on the establishment and growth of a chestnut orchard over a three-year period.
Five treatments were applied to 120 chestnut trees across three planting rows during the initial planting and on an annual basis thereafter, using locally-produced, lab-tested biochar from sustainably-sourced wood. We are analyzing 60 individual trees divided into 20 experimental units. The research will isolate the effects of straight biochar, straight compost, biochar mixed with compost, and biochar mixed with compost and amended with a mix of micronutrients and microorganisms.
We theorize that the introduction of organisms and nutrients carried by biochar at establishment, and the subsequent annual treatments of biochar mixed with compost, will have the synergistic effects of increasing soil organic matter, microorganism abundance, plant uptake of nutrients, and the growth and productivity of the subject chestnut trees. Additionally, the use of biochar will return a stable form of carbon to the soil, which we expect will build soil carbon as trees increase root growth and soil biota habitat.
A survey of Northeastern farmers conducted for this proposal showed broad interest in biochar’s potential as a soil amendment or conditioning, but hesitancy due to a lack of information and data. This study will facilitate farmer engagement by convening a Farmer Working Group of 10 farmers to implement a small-scale trial of the five research treatments on their own farms. Over the duration of this project, farmers will attend two workshops at Arthur’s Point Farm and will collect visual observations on their chestnut trees. This group of farmers will be critical in providing the feedback that will assist in creating a pathway to farmer adoption of this novel approach to regenerative, climate-friendly farming.
Interest in biochar is increasing as a means of enhancing long-term soil fertility and carbon sequestration. A lack of data and farmer experience related to biochar’s benefits and optimal management practices, especially regarding tree crops, is a significant constraint on broader adoption. This project aims to quantify the relationship between inoculated biochar and chestnut trees to provide farmers with a regenerative tool to increase crop vigor and yield. With growing interest in chestnut agroforestry in the Northeast, this project comes at an opportune time for farmers establishing new orchards and for future regional studies with biochar and other tree crops.
Research
The research project is located at Arthur’s Point Farm in New York’s Hudson Valley. The field, which has been used for hay, orchard, and pasture for most of the past two centuries, is hilly with Nassau channery silt loam, primarily composed of silt particles with a large volume of small rocks. The research is being conducted on three 800-foot rows that transect the field and are planted with hybrid Chestnuts (Castanea spp.) and Black locust (Robinia psuedoacacia) alternated at 10-foot spacing and 20 feet between rows. The trees were planted in 2022, the first year of the research project.
Treatments
The biochar used in this study was produced at Arthur's Point Farm using a low temperature pyrolysis (~450℃) thermochemical conversion of sustainably sourced trees and scrap wood from a neighboring lumber mill. The compost was produced from a mixture of livestock manures and animal bedding from a nearby farm. Biochar-compost is created by adding biochar to the compost mix at the start of the composting process.
Treatment 1 (T1): Hybrid Chestnut (Castanea spp.) and Black locust (Robinia pseudoacacia) trees planted into native soil. This treatment represents the most commonly employed method of planting chestnuts. Planting into native soil provides a control for the other treatments.
Treatment 2 (T2): Four cups of raw biochar mixed with native soil in the planting hole. T2 analyzes how biochar reacts with native soil unaccompanied by introduced microbial life.
Treatment 3 (T3): One gallon of compost mixed with native soil in planting holes, top-dressed annually with two gallons of compost. T3 tests the benefits of an accessible and commonly used soil amendment and controls for the effects of compost in the biochar treatments.
Treatment 4 (T4): One gallon of compost and four cups of biochar mixed with native soil in planting holes, top dressed annually with two gallons of biochar-compost. T4 is distinguished from T3 by the addition of biochar, both in the planting hole and mixed into annual top dressings.
Treatment 5 (T5): One gallon of compost, four cups of biochar, and four cups of an amendment of micronutrients, minerals, and beneficial microbes (“amendment”) mixed with native soil in planting holes, top-dressed annually with two gallons of biochar-compost. The amendment consists of alfalfa meal, oat meal, kelp meal, azomite, soil bacteria (Arthrobacter globiformis; Azospirillum brasilense; A. lipoferum; Azotobacter chroococum; A. paspali ; A. vinelandii; Bacillus amyloliquefaciens; B. atrophaeus; B. Licheniformis; B. megaterium; B. pumilus; B. subtilis; Brevibacillus brevis; Micrococcus luteus; Pseudomonas fluorescens; P. putida; Rhodopseudomonas palustris; Rhodospirillum rubrum; Streptomyces griseus) and soil mycorrhizae (Glomus intraradices; G. deserticola; G. etunicatum; G. clarum; G. claroideum; G. mosseae; Gigaspora albida).
Treatment 3 receives an annual top-dressing of compost and Treatments 4 and 5 receive an annual top-dressing of a 10:90 biochar:compost blend. Annual top-dressing applications occur in the spring, starting in the planting year (2022). Hand-weeding is performed as needed. Application rates were based on typical quantities recommended by leading biochar products. All trees in the five treatments are mulched annually with 10 gallons of wood chips.
Data Collection
Data was analyzed using Minitab Statistical software. Soil samples were taken in April of 2022 and (we will sample again in 2025) with a 1.5-inch diameter handheld corer to a depth of 30 centimeters. Soil sampling happened semi-radially around the first chestnut in each experimental unit on each of the three rows (See Figure 3, Soil Sampling Design). The sampling circle has a radius of approximately two and a half feet from the tree. We decided not to collect data in 2023 to save costs and allow us to do the full suite of tests in 2024 and 2025 (growing seasons 3 and 4 of the project). We are hoping this provides greater difference in the results given the longer timeline without any impact in completing the project by the end of 2025.
Soil samples taken from around the study trees were analyzed for microbial abundance, carbon storage, and basic soil health variables. Microbial abundance consists of the quantitation of 17 soil microbial functional groups and 16 relationship indices which demonstrate the direct correlation between soil chemistry and microbial groups.
Carbon tests included water soluble carbon and total organic carbon. Other soil health tests included potassium (K), sodium (Na), calcium (Ca), magnesium (Mg), storage phosphorus (P), Solvita CO2-burst, Solvita labile amino-nitrogen (SLAN), a volumetric aggregate stability test (VAST), nitrate, soil organic matter, pH, C:N ratio, and soil bulk density (BD).
To assess nutrient bioavailability, leaves were collected from a combination of the six chestnut trees in each experimental unit and Wood’s End Lab conducted a plant tissue test to measure levels of nitrogen, phosphorus, potassium, magnesium, calcium, sodium, sulfur, boron, zinc, manganese, iron, copper, and aluminum.
Leaf tissue samples were collected in August 2022 and in August 2024 (we will sample again in 2025). Tree health and vigor was assessed by applying standard tree assessment protocols adapted from the Forest Ecology Monitoring Cooperative (Duncan, 2019), which includes live crown ratio, vigor, dieback, foliage transparency, defoliation, and foliage discoloration. Above ground biomass was determined using a generalized biomass equation (Chojnacky, 2014). Tree health and vigor were evaluated in August 2024 and will be assessed again in 2025.
Deep carbon core samples were taken in March 2022 to a depth of 0.60 m, using a Geoprobe 54DT hydraulic drill rig. Two deep carbon samples (0-0.15 m, and 0.16-0.60 m) were taken in each experimental unit, between the rows, five feet above and below the central row, for a total of 40 samples for carbon and BD. Soil Health, Biochemistry and Nutrients assessed for 60 sample points at 0.15 m depth. A second set of deep carbon core samples will be taken and analyzed in March of 2025.
Hydraulic core samples were air-dried for weight capturing. Bulk density was determined by measuring total soil dry weight versus the sampling tube volume. Stone fractions were separated to calculate particle density of each fraction. Total C was measured on the soil fraction (excluding the stone fraction). The carbon stock was calculated by correcting for soil density.
Farmer Working Group Satellite Research
The ten Farmer Working Group participants were each asked to replicate the research treatments on their respective home farms and were provided with five chestnuts and five black locusts, along with all the materials necessary to apply the research treatments. Each farmer was asked to make visual observation on the health and growth rate of their trees and report back to the research team. Due to budget limitations and logistical challenges, the research was not designed to collect soil samples for these small satellite trials. The farmer observations have been documented in a survey form that follows the same protocol we will use in assessing tree health and vigor at the main research site at Arthur’s Point Farm. Three of the farm participants did not complete these tasks for different reasons - either because they did not manage to plant the research trees or neglected to care for them - and are no longer participating in the satellite trials or the Farmer Working Group.
Soil Health
Baseline soil results in 2022 determined that there was a great difference in soil layers. Apparent BD (g/cc) was 1.443 and 1.876 for 0-0.15 m and 0.16-0.60 m, respectively. The corrected bulk density (g/cc) after stone removal was 1.095 and 1.121 for 0-0.15 m and 0.16-0.60 m, respectively.
The field fertility score was 70% (average of 60 samples). pH was optimal; Ca, Mg adequate N-min was moderate and K-potassium was the most likely deficient crop nutrient element.
Soil health index (based on 7 indicators) ranked 22 (60% of target for the region and soil type). It ranked slightly lower than the target because of lower-than-normal contents of organic matter and carbon. In addition, poor soil structure and aggregation is possibly linked to soil type (Inceptisol). Improvements are likely to be expected.
2024 soil health (average of 59 samples) revealed no significant changes compared to 2022, with an overall fertility score of 68% and a soil health score of 21%. Notably, K exhibited high levels for Treatment 5 and significantly varying levels among treatments, with Treatment 2 exhibiting the lowest amount of this element, at 95% CI for the mean. Conversely, when analyzing fungi levels, treatments with biochar contained higher fungi and lower nutrient levels. We speculate that there could be an indirect effect.
Nutrient chemistry relationships of 1,034 unique pairs of test data for 59 soil samples were examined by comparing microbiological levels with soil health-nutrient variables using Pairwise Pearson Correlation analysis at 95% C.I. Twenty four pairs showed some level of statistical importance (>95% certainty, p < 0.05), 4 pairs showed positive interactions, while 20 had negative correlation meaning that one variable is adversely affected by the other. Furthermore, for instance, higher levels of pH are linked to reduced microbiology. Higher levels of K, Ca, Mg affected microbe utilization negatively with a certainty of 99% (p<0.01). (Figs. Slide 14)
Higher pH and basic elements Ca, K and Mg often result from biochar and compost additions, but compost also provides organic nitrogen
Carbon Stocks
When analyzing total organic carbon (TOC) by soil depth, we found substantial differences. Average TOC in core samples (0-0.15 m) was 1.32% ± 0.34 %, (1.26% ± 0.38 % in fertility samples), whilst in the deeper layer TOC measured 0.19% ± 0.11%.
Carbon stocks (soil organic carbon, SOC) at 0-0.15 m was 17 t ha-1, representing about 60%, while at the remainder soil depth SOC represented 11 t ha-1, indicating great variability between sampling depths and implying that beyond 0.15 m carbon stocks are likely to be low with high variability.
In 2022, no differences in TOC were found among treatments. Traditional organic matter values closely correlated to modern carbon combustion (Figs. Slide 9)
In 2024, there was an apparent 15% decline in TOC from 2022 sampled zones (sampled at 6%). Running a Fisher post hoc means comparison analysis, we found significant differences between treatments, where Treatment 5 (biochar + compost + amendments) presented higher carbon stocks (1.124%) than the rest and Treatment 2 (biochar alone) presenting the least amount of TOC (0.811%). (Figs. Slide 11)
Carbon comparison (%) between 2022 and 2024 showed close correlation, R2 = 0.3463 between years, though with several outliers which may be explained by the sampling variance.
A matrix plot correlating microbiological respiration (12 properties) and total carbon, found no ultimate relation of substrate utilization to other traits, except for TC:CO2 = 0.54, Ca:P = 0.65, F:B:Fungi = 0.69 and Nitrogen fixation:total bacteria = 0.47 (Figs. Slide 12).
Tree Health and Vigor
Tree health and vigor were measured through scoring and scaling six attributes (height, crown, live crown ratio, vigor, dieback and discoloration). In general, desirable performances corresponded to more tissue nitrogen (N) and potassium (K). Thus, 2022 performance correlated with crown height in 2024. (Figs. Slide 15).
Lastly, when analyzing tree health versus treatments by attribute revealed that no statistical differences existed (p<0.05) when comparing treatments versus height (p ≤ 0.079), treatments versus potassium (K) (p ≤ 0.052), treatment versus crown measure (p ≤ 0.058) and treatment versus Tissue Nitrogen (p ≤ 0.10)
Final results incorporating data from 2025 will reveal how the use of biochar, compost and amendments may determine what further research or best practices may be required for this practice / product to be adopted by farmers in the Northeast.
2024 Data
2024 Soil Health and Fertility Report
2022 (Baseline) Data
Education & Outreach Activities and Participation Summary
Educational activities:
Participation Summary:
We conducted an inaugural workshop with the Farm Working Group and collaborating research scientists in March of 2022 (slide presentation). We provided an overview of biochar and described the details of the research being conducted at Arthur's Point and the sample trials that the Working Group members are undertaking on their home farms. We toured the farm and showed the farmers how we currently make and use biochar. We had in-depth discussions about various related topics and then provided the farmers with their research kits (5 chestnut and 5 black locust seedlings, biochar, compost, soil amendment, tree tubes, weed mats, and written instructions). In late 2022, we sent an update to the Farmer Working Group on the research and outreach efforts. We also conducted one-on-one meetings with the three Farmer Advisory Group members.
We presented on the use of biochar and compost on a 2022 Connecticut Compost Webinar Series hosted by the CT Department of Resource Conservation & Development in March of 2022 with over 100 attendees. This presentation included an overview of the SARE project (video recording here).
We also published a blog on our website announcing the launch of the project as well as another blog promoting a bill in Congress that would create a national biochar research network. We discussed our use of biochar with the local USDA Natural Resource Conservation Service extension office during a visit to the farm this past summer. We discussed the newly established soil practice for biochar and was told that they hope to begin offering payment for services through CRP in 2023.
In addition, we hosted two workshops in 2022 with substantial focusses on biochar, including the SARE project work, one for the Berkshire Botanical Garden and the other for the Climate Farm School (presentation).
The SARE research project was also referenced in a report by the American Farmland Trust, the National Center for Appropriate Technology, and the Foundation for Food & Agriculture Research entitled "Scaling Sustainable Biochar Research Commercialization for Agriculture Conservation," published in December of 2022.
In December of 2022, we were interviewed for the Nature Calls podcast, focusing on agroforestry, biochar, and ecological resilience. The episode can be accessed here.
In September of 2022 and 2023, Arthur's Point Farm participated in the Chatham Area Farm Tour, which brought over 50 visitors to the farm each year. Participants were shown the biochar production process on the farm and were given an overview of the SARE research project. In 2022, Arthur's Point Farm also helped to organize the first ever Columbia County Climate Carnival, where we had a booth focused on climate-friendly farming, including with biochar and native perennial plantings. The County is planning another Climate Carnival in September 2024, which we plan to participate in.
Significant time in the Fall-Winter of 2024-2025 has been spent networking with scientists, biochar producers, researchers, and farmers in the region. The primary purpose of this work is to promote our research and to assess other activities and projects in the region. The second purpose is to begin planning interviews and site visits for the short biochar video documentary we are planning this year.
Individual calls with the three Farmer Advisors reviewing the first year's work and discussing ways in which we can continue to engage farmers. Field visits to Farmer Working Group and Advisers in spring of 2023 and 2024 to provide trial amendments, replacement trees, and to give an update on the project.
We are currently conducting a literature review to prepare to write final results on a a manuscript for a peer-reviewed journal article. Extracts of the research will be digested and incorporated in fact sheets and blog articles.
Relevant findings may be presented at conferences, such as the Savannah Institute’s North American Agroforestry Conference, Northern Nut Growers Association Annual Meeting, and the Northeast Organic Farmers Association.
These final products will help farmers, extension services, NRCS service providers and policy makers across the region to better understand the linkages between biochar and other organic amendments, soil health, and tree crop vitality and productivity.
Information Products
- Biochar Agroforestry Research Project Launched
- Farmer Working Group - Inaugural Workshop Presentation - The Use of Biochar in Agroforestry to Promote Soil Microbial Health, Tree Productivity, and Carbon Sequestration
- Climate Farm School Training Presentation - Agroforestry, Biochar & Climate Resilient Farming