Final report for ONC24-139
Project Information
This project's aim will be the reduction of inputs into soil profiles by small farmers, decrease in costs to early season production, increase in biodiversity of the soil, and an injection into the local economy while simultaneously lowering the farm's carbon footprint.
By inoculating locally-available, less expensive and lower-quality compost with a microbially complete product, farmers will reduce early season costs, create a more sustainable soil, contribute to the local economy (rather than outsourcing to nationally-recognized high-quality compost purveyors), and benefit from a more resilient crop as a result of the healthier soil.
The soil's ability to maintain its health through this process will be invaluable to farmers who grow on a small-scale, intensive manner, and rely on soil health practices to produce nutrient-dense food. By making compost more alive and longer lasting, small, diversified crop farmers can reduce costs, increase yield, and improve soil health in a relatively short time.
Objectives
- To prove that microbial life can improve poor compost quality
- To grow more food with fewer economic and off-farm organic inputs
- To improve plant disease and pest resistance
- To extend the life of locally-sourced, lower quality compost
- To decrease farm costs during early season bed preparations
- To educate small farms about soil health practices that can achieve the above
Cooperators
- - Technical Advisor (Educator and Researcher)
- (Researcher)
- (Researcher)
- (Researcher)
- - Technical Advisor (Educator and Researcher)
Research
Research for this project is both qualitative and quantitative, relying on lab analysis and practical visual and experiential analysis by farmers in the project.
Farmers were asked to do a side-by-side comparison of crop yield and resilience of two beds over two years. The first year, the side-by-side comparison was over the control bed that was prepared as the farmer would usually in years and seasons' past, utilizing a local plant-based compost as a top-dressed mulch. The second bed would also use the same local, plant-based compost as a top-dressed mulch, but that would be inoculated with a biologically-complete compost, either also top-dressed on applied as compost tea at the farmer's discretion. Farmers were instructed to treat the beds the same in all other ways and report on the changes they noticed, if any. In the second year, that control bed was then inoculated just as the test bed had been in the previous year, and the bed that was inoculated in the previous year was kept as-is to test for microbial resilience, increase or decrease in organic matter and microbial life, and plant yield.
The lab technician would test the soil at multiple points within the season for microbial life in both years of production and consult with farmers on their opinions of the year's crops.
Microbial Analysis
General observations regarding the soil test showed that there was no significant change from the beginning of the grant to the end of the second year. This was across the board for all three farms who participated.
The markers that were measured include bacterial and fungal biomass measured in ug/g (microgram/gram), protozoa and nematode numbers, and F:B ratio. Each farm started with a high bacterial level and low level of fungal hyphae and this lasted throughout each season with only a couple of instances where it rose above .2. The significance of having fungal hyphae levels with a biomass high enough to bring F:B (fungal to bacterial) ratio above .5 is to have the proper nutrient cycling to allow for nitrogen levels to supply ammonium into the system for a productive vegetable garden. Levels of protozoa and nematodes observed fluctuated throughout the season both years. Very occasionally did numbers meet a standard to allow for nutrient cycling to occur. Predators such as these convert nutrients stored in the bodies of bacteria and fungal hyphae into plant-available food as a consistent source of nutrition for the plant. The nitrogen released from predation is ammonium. Bacterially-dominant soils convert ammonium into nitrate, NO3, which keeps soils in a stage of early succession…that is to say, weedy. Having fungal hyphae brings pH to 6.5 to 6.8 which keeps the nitrifying bacteria from converting ammonium to nitrate.
Compost provided by Integrated Elements Compost had high levels of predators (protozoa in particular) as well as an F:B ratio that was .5 and above both years. Having predators in the system keep bacterial levels down. Despite this, there was little transference into the soils of all three farmers. Not knowing the farming practices of the three farms didn’t seem to matter since the results all showed pretty similar trends. It would be hard to imagine them all practicing the same methods and this being the reason why. The big take away was that there is so much more to learn and research in the art and science of using compost in building soil health. This is not a panacea, but a piece of the overall puzzle. The lack of observable trends in these two short years demonstrates how dynamic soils are and that there are a lot of working parts in learning how to work with soils, farms, and the farmers. Much more research and experimentation that can be done to establish a system to figure out a way to implement means to get predators and fungal components into the soil via compost.
If the trial were to be repeated, more uniformity in application manner and correlating dates of application dates, as well as aligning testing so that each farm’s soils were tested closer together and consistently both years. An alignment of each farmer's growing practices would create a more uniform testing situation as well, as would a similar crop for each farm, a better method established for application -- whether compost in solid or extracted form-- and an incorporation of cover crops, keeping soils covered over winter, and providing a constant source of exudates in the soil by having roots consistently in the ground. However, establishing a standard of practice would have to have flexibility as it ultimately would have to fit within the purview of the farmer and their current process, however, an abundance of cash flow and farming don’t necessarily run parallel to each other and using equipment readily available on-farm would make the most economical sense in applying the compost.
Results by Farm
Finney Family Farm did show an improvement for the first year, 2024, from the beginning of the season to the end, using the marker of F:B ratio.
Both the control side and treatment side improved from the baseline of .03 to .09 in the control and .18 in the treatment side. However, no predators were noted in the soil at the end of the season, but were present in the middle of the season, with a higher ratio of F:B, .24 control and .79 treatment.
Season 2, 2025 started with a stronger F:B ratio on 2024 treatment side at .13. No predators noted throughout the second season which would trend soil to a higher bacterial environment. F:B was low at the end of the season, .05 treatment, .04 control.
Berry Goods Farm showed no significant change throughout both seasons in regards to F:B ratio, typically.02-.07, except for final assessment on 12/18/25 results of F:B in treatment side was .14. Predators only noted mid season in 2024, otherwise not present throughout rest of assessments.
Summer Solstice Farm showed little significant change in F:B ratio, except for once in the control plot on first season at the end where a spike of F:B rose to .17. Similar findings to the other farms regarding protozoa numbers. They simply did not present consistently enough throughout the test, particularly the second year. The first year did show protozoa mid season both control and treatment and for treatment plot at the end of 2024. Protozoa present at onset of 2025, however, nothing noted mid to end of season.
There were two different batches of compost provided in the first first of experimentation. Compost provided in the first year for Finney Family Farm and Summer Solstice Farms showed F:B .53 with 800,000 plus protozoa and 400 bacterial feeder nematodes present in 1 mL of soil agitated in 9 mL of water to make a dilution ratio of 1:10. Berry Goods Farm's compost was .82 for F:B and 800,000 plus protozoa and 200 bacterial feeding nematodes.
2025 compost provided was the same for all three farms, with and F:B .5 and 800,000 plus protozoa and 200 bacterial feeding nematodes. This shows that the product used was of a high quality, providing adequate fungal biomass and protozoa for predation and subsequent nutrient cycling. However, the results of the compost did not integrate well into the soil. This poses the questions raised regarding application method and timing of application in reference to testing of soils.
A possible improvement to consider when using biologically active compost is to apply when the ground is moist, spring for instance. Also, to consider applying just before a heavy rain, in order to drive the microbes into the soil. With high volumes of bacterial biomass in soils consider the following…a quick search of how much nitrogen is available in soils, compost even, will reveal that a gram of soil that contains 2000 micrograms of bacterial will have 200 to 600 micrograms (ug) stored within that bacterial biomass. This is what is locked in the living cells. This translates into 400 to 1200 pounds of nitrogen locked up in the bacterial biomass. As an example, field corn typically requires 180 to 250 pounds of nitrogen per acre. Nitrogen, would not be the only nutrient locked up and available when properly released. This is why having the proper biology available in soils makes economical sense.
Conclusion
As with any inconclusive result, the brief time allotted could reveal more relevant data, as would a more reliable and consistent methodology for compost application, cropping, and testing of soils.
Farmers reported some increase in productivity that may or may not have been related to compost application as both years of production had a variety of factors that could not be controlled, like weather, pest pressure, and individual farmers' perception of beds over the two year period.
A larger base for comparison within a more controlled environment might offer more reliable and repeatable data. The only negative reported was increased time and energy used for compost application that one farmer reported that didn't imagine adopting on-farm.
In conclusion, no results of conclusive evidence within this two year period that the application of microbially complete compost had any lasting positive or negative effect on crop production or soil health within the time-frame tested.
Educational & Outreach Activities
Participation summary:
Completed both webinar and online tutorials discussing project, goals, and early conclusions. There is an intention to continue education at Small Farms Conference (via Purdue) in 2027.
Learning Outcomes
Utilizing compost as mulch for weed suppressant and water retention
Increasing the nutritive value of compost by increasing microbial content
Using compost teas as delivery system for microbial health
Project Outcomes
With this project, it has come into clearer focus that more can be done to increase soil health through microbial methods and it will take longer to transform depleted soils than the study was able to measure. However, it does not mean that more sustainable methods of production had not been identified. Any effort in the increase of soil organic matter and soil life is not wasted. Although it may not demonstrate a measurable change within the two year period, that does not mean that more research would be a lost cause.
Closing the loop on off-farm compost sources or nutrient additives is a goal for many small farmers, as it is a major source of time, effort, and expense.
We hope that the initial results can inspire further research or stronger control methods in evaluating how soil health can be built utilizing on-farm resources or local resources.
Further and more solid methodical research is needed in this sphere. These results would benefit from longer term study, and better control markers for more valuable insights into long-term soil health and microbial trends.