Evaluating the Environmental Benefits and Economic Opportunities of In-Vessel Composting Solid Dairy Manure

Final report for FNC15-991

Project Type: Farmer/Rancher
Funds awarded in 2015: $22,500.00
Projected End Date: 02/15/2017
Region: North Central
State: Wisconsin
Project Coordinator:
Andrew R. Skwor, PE, CPESC
MSA Professional Services, Inc.
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Project Information

Summary:

The grant operation encompassed three host farms: Endres Berryridge Farms, Maier Farms, and Hoffman Farms.  Jeff Endres, partner at Berryridge Farms, led the grant project and assisted the other two host farms by educating their owners on compost development.  All three farms are located in northcentral Dane County, Wisconsin and within the Yahara River watershed.

Berryridge Farms is a dairy operation owned by three brothers: Jeff, Randy and Steve Endres. The diary operation includes 500 Holstein milk cows, 400 heifers and 1,100 acres.  The cropland is made up of 550 acres of corn, 300 acres of alfalfa and grass, and the balance made up of soybeans and wheat.

Maier Farms is a dairy operation composed of 650 cows and 1,400 acres of tillable ground. The cropland is in a corn and alfalfa rotation.

Hoffman Farms is a dairy and steer operation that milks 300 dairy cows and has 300 steers on feed at all times. They operate 1,200 acres of cropland on which they grow corn, alfalfa and wheat.

The grant allowed the three farms to create and manage windrows of their own materials to be composted. In addition, the three farms utilized bedded-pack manures as their composting base and then added other feedstocks, (feed residuals, grass, waste baleage, etc.) if they were available, at the time of windrow creation.  The grant project had one windrow per farm for a total of three windrows.

Introduction:

Endres Berryridge Farms has utilized or been a part of many types of sustainable practices throughout its operation:

  • Cover crops on tillable lands, excluding alfalfa fields for the last six years
  • Various tillage practices: conservation tillage for the first 30 years, no-till for the following 20 years and strip tillage for the last three years
  • Wetland revitalization project with County, started five years ago, to convert farmland back into a wetland
  • Native grass buffers were created in collaboration with Dane County that could be harvested for livestock feed and bedding. This was part of the wetland restoration plan started five years ago.
  • A United States Geological Survey (USGS) monitoring station was hosted to evaluate water quality and quantity from tiles and surface water runoff. This project was started four years ago and finished last spring.

The farm owners and operators are members of Yahara Pride Farm and the Clean Lakes Alliance. Scott Maier and Jeff Endres are current board members. Yahara Pride Farms is a farmer-led organization that evaluates and promotes management techniques and technologies to reduce nutrient transport to the Madison, WI chain of lakes. Yahara Pride Farms has evaluated new manure application technologies, cost-shared the planting of cover crops, and developed and implemented a sustainable farm certification program to identify high-risk practices for farmers. Many of these practices have been completed over the last 5 years and continue to be researched.

Project Objectives:

There are two ultimate questions for this grant project:

  1. Could composting be incorporated into the farming system in an economic and workable way?
  2. Is composting a best management practice for moving nutrients out of a watershed?

In order to answer these questions, farm operations have to look at several aspects:

  1. Where are they going to compost?
  2. How much time can be allocated to composting?
  3. What needs to change operationally?

Does the composting system fit within current ordinances and regulations? Berryridge Farms began planning and developing the project by answering the above questions. The farm owned a reclaimed commercial pit. When the pit was acquired, area contractors had wasted soils there and those soils were leveled and graded to make a uniform, flat surface with perimeter ditches to handle stormwater. This reclaimed site made nearly a perfect working surface and was well vegetated to section off buffers for runoff control. The farm currently stacks their dry, solid manures and feed residuals when it cannot be applied to working fields or pastures. The farm felt they could easily integrate the windrow creation and management. The only difference was where they were transporting their feedstocks for composting. The transportation of the feedstocks to the reclaimed pit was a time saver because it was closer to the production area, was large enough to handle the volume of material they estimated, and could be easily organized to save stacking time.

As with many farming systems, there are unanticipated changes that occur. In this project’s case, the application for the grant was written to operate and maintain a proprietary, predeveloped in-vessel system. Due to equipment availability, the system had to be changed to a windrow system. This change increased cost because a turner had to be rented or leased and additional labor hired. The farm was able to locate a custom compost turner from a company which could be operated by one of the farm’s tractors as the alternate.

The other host farms went through a similar process to site their windrows. One was within the production area of the farm and the second was along a field access road. Both locations allowed for good access and were maintainable.Windrows at all facilities were made mid-July. Delay in start-up was due to weather, scheduling and completing other farm activities, such as planting. All windrows were created from bedded-pack manures with some minor differences. Those differences included feed refusal in one windrow and shredded drywall as bedding in another.Windrows were monitored on a 10 day cycle by visual inspection and temperature. Each windrow was turned three times during its breakdown cycle of 4 months or approximately 13 weeks. These results can be evaluated in Table 1.

The composting project had the goal of answering nine questions:

  1. Do we have alternatives to spreading bedding pack manure on fields in the winter by utilizing composting?
  2. Does composting bedding pack manure give the farmers options to be able to sell their excess nutrients from their farms in the form of compost?
  3. Could we develop a product that is marketable and profitable for operations?
  4. What are the economic benefits of using composted bedding pack manure?
  5. What are the environmental benefits?
  6. Does composting help our watershed manage manure more effectively as a whole?
  7. Are there disadvantages of using composted bedding pack on the herd?
  8. Could we double the benefit of using corn stalk and straw by being able to re-enter it in free stall barns after the compost process?
  9. Does spreading of bedded pack manure on cropland in the winter slow down the warming up of soils in the spring and could it delay planting?

Cooperators

Click linked name(s) to expand
  • Jeff Endres
  • Jeremy Huffman
  • Scott Maier

Research

Materials and methods:

The compost windrows were made during the cleanout of a bedded pack facility. They were made with typical hauling (manure spreader or dump box trailer) and loading equipment (skid steer or payloader).  Each windrow, when completed was mixed for uniformity and to get as much air/oxygen into the pile as possible.  One windrow was constructed with a Tebbe spreader which allowed the bedded pack manure to be hauled, mixed, and placed with one pass.

Please refer to page 5 of the Compost-Trial-Handout. Listed here are several soil samples to evaluate the potential for groundwater contamination.  Total nitrogen was evaluated because the nitrogen would get absorbed into the stormwater or would likely be leached from the pile.  The first two results are taken adjacent to the pile for a base line of nitrogen in two locations parallel to the windrow.  The next three samples were taken from under the pile in the working surface at depths of 1 and 2 feet.  The amount of nitrogen (ppm) is not leaching to great depths of the soil strata and does not appear to be a danger to groundwater.  Please note the working surface has everything to do with the nutrient transport through the soil; the more heavy silts and clays there are in the working surface, the better the protection.  In addition, higher nutrients in the upper layer from rotating the windrows and letting vegetation reestablish, will uptake the nitrogen and other nutrients in the upper layer of the surface.

As the composting process progressed, temperature readings and a visual inspection were completed approximately every 10 days. The State of Wisconsin Department of Natural Resources has Administrative Code NR 502 which regulates composting in the state of Wisconsin for exempt and non-exempt facilities and it gives guidelines to determine quality.  In this case, the requirement that a windrow maintains a temperature of 131oF for at least 15 days is what Table 1 is intended to show.  One out of three windrows met the requirement and certainly a second windrow had the potential to meet the requirement.  By definition, none of the compost meets Class A requirements because the windrow has to be turned a minimum of 5 times during maximum temperature.  By no means does this evidence show the compost is insufficient, it simply means the compost is of Class B quality and does not have the adequate management to optimize pathogen and weed seed destruction.

At the end of the composting cycle, samples were taken from all three windrows and evaluated for quality at a third-party laboratory. The attached finished compost analyses show the direct results.  In general, all three reports indicate a finished compost with adequate nutrients that can be applied to just about any growing crop.  Each test shows similar traits of the feedstock.  For example, Farm A had the drywall in the bedding and it is reflected in the higher calcium number, whereas Farm C more than likely had feed refusal in the compost mix because its nutrient value is higher. 

An interesting point to make is Farm B’s finished compost had a moisture content just above 60%.  All these piles were created with moistures in the range of 40-50% and at the time of sampling multiple rain events occurred leading up to sampling.  When sampled, none of the windrows showed signs of saturation or excessive leaching.  This is evidence of the water retaining ability of compost and one of the more pronounced properties of compost in amending soils.

Research results and discussion:

Economically, composting makes sense. For one case study, the project monitored the time to clean one bedded-pack barn for field application and one bedded-pack barn for composting.  The same barn was used and hauling equipment averaged 12 ton per load:

Field Application:

  • Tractor and slinger spreader – $60/hr
  • 2 loads per hour production rate
  • 10 hrs to haul and spread on fields
  • Cost of $600.00

Compost windrow creation:

  • Tractor and dump trailer – $40/hr
  • 3 loads per hour could be done because of the shorter haul
  • 7 hrs to haul and windrow
  • Cost of $280.00, a savings of $320.00 to the specific farm.

In order to manage those windrows, we estimated $5 per ton for turning and management:

  • 240 tons per windrow * $5.00/ton = $1,200.00

(Production cost per ton of compost is just less than $6.20 per ton)

If the finished compost was spread on field and utilized on-farm, the cost can be projected as:

  • 2 loads per hour for production rate and 7 loads to haul to the field   
  • 3.5 hrs of time = $210.00 in cost

The other way to value compost is from the agronomic standpoint. Every compost is going to be different and have different amounts of macro and micro nutrients. From our project, it is fair to value the compost created to be within the range of $24 to $37 per ton. Please keep in mind, this valuation is based off known nutrient value and does not take into account some of the other benefits of composting, such as more available nutrients to the plants, less tons per acre applied, and less trips into the field resulting in less compaction. Thus to find a buyer of compost at $35/ton has substantial value added for the farmer.

Composting is viewed as a very environmentally friendly practice. The ability of compost to absorb and hold more water reduces erosion and increases infiltration. The increase of organic content when using compost can reduce the amount of herbicide needed to manage lands, but also is able to retain fertilizer better. The compost addition to soils increases soil structure and soil biology, which ultimately comes back to increase in yields. This was not verified by this project, but other project results have indicated this project’s results would be the same or similar.

Finally, socially, composting is viewed as a better management practice than direct field spreading. Composting does take more time to manage properly, but has many more benefits in sustainable agriculture. As eluded to earlier, farm owners were able to get a great product with minimal management, so if a farmer is going to reach for the best product, more time and management will be needed to get there.

 

 

Participation Summary
3 Farmers participating in research

Educational & Outreach Activities

Participation Summary

Education/outreach description:

The project was introduced at the Yahara Pride Farms field day or what is referred to as Ag Innovation Days. In late summer, over 100 farmers and attendees were introduced to the project and the benefits that were developing.  Later in November, with the support of many, a Compost Trial Day was held where 35-40 farmers came to see equipment and the results of the project.  Finally, at the annual whole watershed meeting in spring of 2016, the results were presented to all attendees.  An example of a handout was used at the Compost Trial Day in November.  See Compost Trial Handout.

Learning Outcomes

Lessons Learned:

Ultimately, the results of this project were as expected and in some cases our expectations were exceeded. The project was able to answer 8 out of the 9 questions, a product could be developed for bedding heifers, and finished compost can be applied to hay ground during growing season without worries of burning.

These project windrows finished before winter set in, but other piles were created and upon completion of this report, composting temperatures in excess of 120o were being maintained in the windrows.  Composting in the winter verses winter spreading has great potential.

Marketing and finding buyers is the key to making on-farm compost have value. One of the farms was able to sell finished compost to another farmer outside of the watershed for $35 per ton.

One of the farms used compost that only made it through half of the process time and bedded heifers to see if it had advantages (compiled photos). The compost was used in deep bedded freestalls and alleys continued to be daily scraped.  Straight compost did not seem to have much benefit. Alleys were slippery and stalls took on moisture requiring more maintenance.  The preferred bedding mixture was 2 parts compost to 1 part sand.  Stalls stayed dryer and alleys maintained traction.  Animal cleanliness was relatively similar to sand bedding.  This type of bedding system was a better environment for hairy hoof warts and even though warts were present previous to the bedding change, this emphasized the importance of a more consistent treatment schedule for the warts.  No laminitis developed with the bedding change.  No other factors were seen with the bedding change.  These included, but are not limited to no change in mastitis cases and no blind quarters when heifers calved in for the first time. More experimentation is needed, but this offers great potential for reuse of materials.

Project Outcomes

Recommendations:

Potential Contributions

A special thank you goes out to all who were involved in putting this project together:

Jeff Endres, Endres’ Berryridge Farms LLC

Scott Maier, Maier Farms

Jeremy Hoffman, Hoffman Farms

Rachel (Fossum) Rushmann and Natalie Endres, Yahara Pride Farms

Jason Fuller, Fuller Ag Service

Jacob Getz and Scott Evans, Insight FS

Natural Resource Conservation Service (NRCS)

North Central Region – SARE

Future Recommendations

With so many more positives than negatives, these farms plan to continue to manage their drier, more solid manures by composting rather than stacking. Siting long-term areas for farmers to use or rotate through is the key to continuing the success of this grant project. In addition, the specialized equipment cost can make this an impractical option.  Since the Yahara Pride Farms group has already built a sense of community, a more viable option may be a community compost turner to keep cost of production lower thus increasing the value to each farm. The only other change would be increased management to better capture mineralization of nutrients and optimize production.  A community program could be developed to hire a part-time person to manage the program for all watershed farmers involved in the composting program. Each farm would need additional labor to manage the piles, which also adds cost.

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.