Effectiveness of Aerated Static Pile to Windrow Composting on Small-Scale Farms

Final Report for FNE14-803

Project Type: Farmer
Funds awarded in 2014: $6,237.00
Projected End Date: 12/31/2014
Region: Northeast
State: Maryland
Project Leader:
Emma Jagoz
Moon Valley Farm
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Project Information

Summary:

Modern commercial composting facilities largely use aerated static piles (ASP) for increased efficiency, fast turnaround, odor reduction, and a superior product. Small farmers, on the other hand, predominantly use windrows to make their compost– a cheap, labor-intensive, tried-and-true method. We merged the technology of modern facilities with the needs of the small farm.  A small-scale ASP system is a much more efficient use of farmers’ valuable time, labor and space, and produces superior compost for their soils.

For this study, we created a small-scale, replicable ASP system to be adapted by farmers, using the expertise of technical advisor & ecological designer Adam Schwartz. We compared the capital, labor, and time spent on windrow-produced compost – the method currently used by most farmers, including myself – with our ASP model.  We predicted that the ASP model will be hugely beneficial for the small farmer,  as a labor- and space- saving method that creates a superior product.

We found that the quality of the compost from the windrow and ASP system were comparable to one another, and of high quality, based on compost tests of the finished products evaluated at Penn State University.  The ASP composting took less labor hours to create and maintain than the windrow system, and also had a smaller footprint.  While the ASP system took approximately $1,850 to build, we argue that it is a worthwhile long-term investment for the small farmer, as it can save about the same amount of money every year on purchased compost.  For the small farm interested in sustainability – financial & environmental sustainability – ASP composting should be a serious consideration as it can capitalize on waste products, create quality compost in less time, with less labor hours, in smaller spaces. 

Introduction:

Small, organic farms have a great need for finished compost, but many have trouble producing enough for their farms in a timely manner, and in an efficient use of space.  I am one of many small-scale farmers who can’t seem to efficiently make enough compost fast enough to meet my needs, despite having a plethora of ingredients. 

I am Emma Jagoz, a young farmer in the suburbs of Baltimore City, growing vegetables, herbs, and native fruits, and a flock of hens and ducks for eggs, for a 70 person CSA and for restaurant sales.  I am farming five suburban locations now, at a total of 3 acres of intensive vegetable production.  I am a compost nerd, and believe that farmers should take the initiative to create their own compost and thus soil health and fertility.

Adam Schwartz, technical advisor for this project, was a compost specialist at Chesapeake Compost Works and a former farmer, and now does ecological design with his business, Symbiosis Design/Build. 

Moon Valley Farm has a walking tractor and uses mostly hand tools, but lacks the expensive front loader, and creating compost in windrows using pitchforks to turn and maintain them, was labor-intensive and time-consuming.  The aerated static pile (ASP) system was intriguing to us as a potential answer to this problem.  Adam firmly believed that the ASP system he used at the commercial compost facility was the right technology for the small farm, but that small farmers didn’t know about it or implement it.  With this system, farmers can produce more compost in a smaller footprint, with no manual turning, and have consistent results. 

We have the compost ingredients, the need for compost, the passion for it, the support of the community (through our free compost program & CSA), & the drive for sustainability.  We merged this with the technical expertise of Adam Schwartz, and created a system we think can change small-scale farming for the better.

Project Objectives:

Moon Valley Farm built a replicable ASP system, and created active compost piles in it as well as static piles in our windrow compost system.  We carefully documented the time, labor, and efficiency of both the windrow system and the ASP system, to compare their overall quality and effectiveness for the benefit of small-farms everywhere.  We sent samples of the final products from each system to a lab for quality analysis.

We took the findings of our research to the community, through on-site workshops with area vegetable farmers & horse owners, and created a promotional video that is available online.  We are working on compiling straight-forward instructions on how to create this system for your own farm, as it is not yet widely available and will be invaluable to farmers who are looking to add an efficient composting system to their farm.

Cooperators

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Research

Materials and methods:

The objective of this project was to evaluate the efficiency of the aerated static pile (ASP) composting as a viable solution to small farm nutrient management.  We compared our new ASP system with the traditional method of windrow composting, and purchased compost.

In March-April 2014, we constructed the ASP system on the farm.  We edited the original proposed design of the system to exclude solar power and a concrete loading base, to make the system affordable for the farm to finance without SARE funding for this infrastructure.  Other than those modifications, we built the ASP system according to plan, with 3 bays, a roof, perforated PVC pipes, gravel, and a blower fan on a timer.

From April through the present, we’ve been creating compost in both the traditional windrows and the ASP system.  We began recording the time spent on both systems - recorded labor hours, ingredients used in the heaps, daily temperatures, and watering.  See the attached charts with that information. 

We made 8 piles in the ASP system throughout the season, and 6 windrow piles.  We had the windrows and ASP system running simultaneously – sifting and making new heaps whenever we could.  We did not record all the details for every single heap, as the season got busy and chaotic, as it does, but we did fully monitor and record more than half of them.  

Additionally, we found it difficult to accurately measure the amount of cubic yards we created.  We almost immediately used any available compost, and the piles of finished compost are difficult to measure, in that they’re not even (the piles taper at the top, naturally, which makes it more difficult to produce an accurate measurement).  I’m confident we produced over 25 cubic yards of compost since we build the system, based on rudimentary measurements, but am not sure of the exact production. 

We analyzed compost created from both systems, sent to Pennsylvania State University soil testing laboratory, from the center of completed piles.  The piles had been curing for several weeks when the samples were taken.  See the attached compost sample reports for the data. 

Research results and discussion:

We designed and built a small-scale, replicable aerated static pile system.  We custom-built this system to fit the needs of Moon Valley Farm, and it is easily adaptable to the needs of other farms/farmers.  Additionally, we maintained the windrow pile system we had on our farm, and documented our recipe, time/labor hours, and quality for both systems.

We were able to complete and document 8 compost piles from the ASP system, and 6 windrow piles this season.  The results that we see clearly from this project, is that the ASP system is undeniably a better use of the farmers time.  The labor hours spent loading the bays versus creating a windrow were very comparable.  But from start to finish, the labor hours spent manually turning the windrows was significantly more than the time spent monitoring and watering the static piles.  We found that the ASP system took, on average, 4 fewer labor hours to create and maintain piles compared to the windrow system.  The two systems took approximately the same amount of time to create and monitor temperature and moisture levels, but the windrow system took additional hours to turn before sifting in order to ensure that the outer layers of the pile were thoroughly composted.  

Additionally, the ASP system is also clearly a superior use of space, which matters very much on urban and/or suburban farms.  We just lack the space that larger farms have more in abundance, and being able to produce as much or more compost in less square footage is very important.  The piles were approximately the same volume, though they varied depending on the availability of materials.  The footprint of the ASP system was smaller than that of the windrow system, by 108 square feet.  However, the footprint of the windrow system was decreased this season from previous seasons, because our needs from it were decreased due to the production from the new aerated system.  Thus, if we had set out to produce all our compost needs from windrows, the footprint of the windrow system would have been significantly higher.

We tested finished compost samples from the two systems, and a third of an older finished heap from the previous year as a control.  According to our compost sample analysis, the quality of the compost produced is comparable.  Both are well suited for soil amending and vegetable production.  However, the pH levels being a little high (7.7) for the ASP system (compared to the 7.0 pH for the windrow, and a 6.4pH for the control).  We believe that is due to an excess of nitrogen-heavy food scraps in those piles, and that we can easily adjust the initial compost recipe to lower the food scrap inputs.  There was a learning curve for us in adjusting the compost recipe for the aerated system, because it needs to be more calculated to allow for airflow.  We used more wood chips and food scraps in the heaps than we traditionally do in the windrows to compensate, and are still adjusting the recipe to reflect what works best for the system. See the attached compost results for more details on the samples.

Moon Valley Farm spent less than $2,000 on the creation of this system (see parts list attached), which will last for years to come.  With this system, we will be able to produce approximately 50 cubic yards per year, which will be plenty to maintain our 3 acres of vegetable production.  Assuming we needed to purchase that compost from a commercial facility, we’d be saving over $1500 per season.  After a few seasons, we won’t need that much compost to maintain our fertility (we’re using more now in order to break up our clay soils, increase our cation exchange capacity and establish fertility), and will be able to sell finished compost as a value-added product, either bagged to home gardeners or by the truckload.  This minimal investment, therefore, has the capacity to eliminate our purchased compost needs as well as make us money in the long run. 

Participation Summary

Education & Outreach Activities and Participation Summary

Participation Summary:

Education/outreach description:

We hosted several farmer meetups to show our results and to share our composting methods.  We advertised through our local farmer meetup groups, on social media, and through our local Ag Center, and got approximately 4 dozens of area farmers and horse owners to attend one of our 3 gatherings. 

At those gatherings, we showed our video: https://youtu.be/eDv79H_CEMY to the farmers, shared with them our composting efforts, including how we built the ASP system, how we load a bay, what the final compost looks like, and how we compared with our passively-aerated windrows.  

We also gave them copies of our ASP Compost Manual, attached, which gives details on why ASP and how to build and maintain a system yourself.

Project Outcomes

Assessment of Project Approach and Areas of Further Study:

Future Recommendations

We did indeed answer our question – whether or not ASP composting makes sense for the small farmer – and it does.  We will most definitely produce the bulk or even entirety of our compost using the ASP method from here on out.  We hope to be able to produce enough compost so that we can even use it as a value-added product in the future – though we’d have to stop increasing our acreage for vegetable production first! 

 

I am confident that this method of composting can and should be shared with other farmers and horse owners in the area.   Local farm conferences, such as Future Harvest CASA and PASA could benefit from presentations on ASP systems for the small farm.  Farmers can certainly benefit from visiting our farm and checking out the system for themselves, and/or checking out our video and ASP manual.    

 

I think more farmers can and should adopt this method and share with others farmers the benefits.  I know that not everyone is as excited about the potentials of compost as we are, but this system makes enough financial and environmental sense that even compost nay-sayers might decide they want an ASP system of their own.  A small space, a minimum amount of labor hours, and a small investment can produce huge amounts of compost in a short amount of time, quality enough to sell. 

Information Products

  • ASP Composting Manual (Manual/Guide)
  • Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture or SARE.