Agricultural Composting:
A Feasibility Study for New York Farms

Eileen E. Fabian, Tom L. Richard, David Kay,
David Allee, Joe Regenstein
February 1993


This Staff Report is a reprint of the final report of a project entitled, "Agricultural Composting: A Feasibility Study of New York Farms." The final report was prepared for the New York State Department of Agriculture and Markets who funded the project. The report was dated July 1992. The principal investigators were David Allee and Joe Regenstein. The authors of this report are: Eileen E. Fabian and Tom L. Richard Department of Agricultural and Biological Engineering David Kay and David Allee Department of Agricultural Economics Joe Regenstein, Department of Food Science Cornell University, Ithaca, NY 14853

Acknowledgements: This project would not have been possible without the cooperation and support of a number of groups and individuals. In the forefront are the farmers who cooperated with this project. Elizabeth Henderson and David Stern of Rose Valley Farm, Karl Hammer and Nels Johnson of Moody Hill Farms, and Fred Feit and Wayne Gerster of Gerster Farms very generously assisted with the detailed analysis of their operations and costs. They, plus Gary Tennant of Cornell Farm Services, Ros Parks of The Earth Works Farm, and Brett Kreher of Kreher Poultry Farms opened their farms to visitors through our series of Farm Field Days. Layne Martin of Seneca Foods and Ron Space Jr. of the Space Farm, and several of the previously listed cooperators provided samples of a variety of their waste materials to help develop a data base of material characteristics.

A number of students and staff at Cornell also played important roles. Kimberly Emerson, Hai Quan, Jay Regan, Laura German and Mark Dienert provided important assistance with the experimental studies and data collection. Victoria Wishart and Jennifer Shin coordinated the publicity and registration for the Farm Field Days. Sue Fredenburg provided secretarial support for this final report. Finally, the New York State Department of Agriculture and Markets, who funded this project, are to be complemented on their foresight and proactive approach. With the continued support and encouragement of all these groups, the future of agricultural composting is looking very bright.

Cornell University is an equal opportunity, affirmative action educator.


TABLE OF CONTENTS

Introduction
Economic Opportunities for Farm Composting - Focus on Production Costs
Costs of Composting
Case Studies in Agricultural Composting
Agricultural Composting: Process Optimization
Recommendations for Agricultural Composting
References
Appendices


AGRICULTURAL COMPOSTING: A FEASIBILITY STUDY FOR NEW YORK FARMS


Introduction

Agricultural composting is experiencing a resurgence of activity, particularly in the Northeastern U.S. Three fundamental factors are driving this interest: environmental and community constraints on traditional manure management options, increased understanding of the agronomic benefits of compost utilization, and rising disposal costs for materials such as municipal yard waste and food processing wastes which might be managed for a profit in an agricultural setting. Although these factors are encouraging many farmers to re-evaluate composting, there are important tradeoffs to consider as well. Equipment and labor costs, land, and management requirements can be significant, and compost production and utilization techniques are not well established.

This project, supported by the New York State Department of Agriculture and Markets, explored these issues with the help of a variety of cooperating farms. The objectives of the project include:

  1. Demonstrate the economic opportunities for farm compost enterprises, including capital costs, labor and land requirements, and market potential.
  2. Document the challenges and opportunities for integrating composting with other farm activities, including farm waste management, and the possibilities for enhancing seasonal stability in farm labor needs.
  3. Analyze technical and economic tradeoffs between three different types of process technologies. (high volume, expensive specialized compost turning equipment; turning piles with common farm loaders; static pile)
  4. Identify the optimum process requirements for composting a wide variety of agricultural and food waste materials.
  5. Initiate an environmental monitoring program which can be used to evaluate the surface and ground water quality impacts of agricultural composting facilities. (Project results available in a separate final report.)
The project included a range of activities in order to accomplish these objectives. The tangible products of the effort are summarized below.

Regulatory Procedures for Farm Compost Site Approvals

Under current DEC solid waste regulations a Part 360 Permit is required for composting sites which process over 3000 cubic yards of yard waste annually, or compost waste paper or other materials classified as sludge or solid waste. Agricultural and food processing wastes are exempt from this permitting requirement. To simplify the permitting process, we developed a generic permit application form in cooperation with the NYS DEC which is suitable for facilities combining agricultural wastes and yard debris. A copy of this generic permit application form is provided in Appendix A. Most of the farms which cooperated in this feasibility study were not required to obtain a Part 360 permit since they used incoming organic materials as bedding or did not exceed 3000 cubic yards of waste annually.

Agricultural Composting Field Days

Demonstration site tours were held at each of the cooperating farm compost sites (see appendix C for dates). The field days included an educational program providing an overview of farm composting principles. Presentations focused on the practical and economic issues associated with successful composting enterprises. Attendance at the tours was excellent, with a total of 131 people participating (See appendix B). Audience members consisted of representatives of other universities, organic farmers, dairy farmers, regulatory personnel, Cooperative Extension and Soil Conservation Service agents, compost equipment representatives, industry members with organic material to dispose of and persons generally interested in compost technology.

Farm Compost Planning Workbook: Extension Publication (NRAES)

To provide information in a format accessible to farmers, the principals of this project cooperated in a regional effort to develop an On-Farm Composting Manual through the Northeast Regional Agricultural Engineering Service. The resulting 186 page manual is available from NRAES (Riley Robb Hall, Cornell University, Ithaca, NY 14853) or through Cooperative Extension offices at a price of $15. This publication covers the requirements for developing and operating an on-farm composting facility. It includes fundamentals of how composting works; benefits and detriments to the farm operation; planning the compost operation's capital, labor and land requirements; consideration of process requirements for different waste materials; equipment and process options; monitoring requirements; regulation requirements; product marketing considerations; and economic evaluations and case studies of alternative composting operations. This manual is intended to provide the documentation farmers need to understand and implement a successful agricultural composting enterprise, and has been ordered for national distribution by the Soil Conservation Service.

Raw Materials Data Base

A data base was developed of important chemical and physical characteristics of raw materials commonly used in farm composting. This information is important for determining mixture ratios for compost materials and estimating amendment requirements. Twenty materials such as animal manures, food processing wastes, wood and vegetative debris and other compostable materials were analyzed for their carbon-nitrogen ratio, nutrient analysis, pH, moisture level, solids content, particle size distribution and other physical and chemical parameters. Appendix E contains this raw materials data base.

Pilot Scale Mixture Study

Mixtures of dairy and poultry manures with varying levels of bedding were analyzed over time for composting changes in moisture content, temperature, fats content, nitrogen level and carbohydrates. Food processing wastes and mixtures containing dead chickens were also studied. The results of these trials indicated a wide range of flexibility in farm composting mixture options, and have been incorporated in the NRAES farm composting guide described above.

Environmental Monitoring and Management

In order to resolve issues about agricultural composting impacts on water quality, a complementary project is monitoring and evaluating compost site leachate. A comprehensive environmental monitoring program has been developed and implemented at each farm compost site. Results of this study are provided in a separate report entitled Agricultural Composting: Environmental Monitoring and Management (Rymshaw et al., 1992).

The remainder of this report details the work that went into developing these products. Economic analysis, case studies of the cooperating farms, and the details of the experimental program and data base development are discussed.

Economic Opportunities for Farm Composting - Focus on Production Costs

General Economics

A few commercial and farm composts are reportedly marketed at bulk prices of hundreds of dollars per (dry) ton. However, most of the compost currently being produced does not command such prices. Instead, it is given away, used directly by a farm or local government composter, or sold for prices under $10 per cubic yard in bulk.

In general, finished compost is highly regarded for its ability to improve soils and enhance plant growth. It can reduce erosion, disease and weed germination while enhancing the nutrient and water retention capacity, tilth and overall productivity of the soil. Though not normally marketed as fertilizer, compost does add valuable nutrients to the soil. Satisfied compost users range from home gardeners and landscapers to farmers and local government public works departments. Even low grade, poorly sorted composts with contaminants can be useful in applications such as final landfill cover or mining reclamation. Producers of uniform, high quality compost have had little trouble finding acceptance of their product among a wide variety of regular users of other top dressings, mulches and soil amendments. Opportunities to develop better paying markets for compost have only begun to be exploited.

Like most products, the price that can be charged for a given compost or compost mix depends on its consistency, overall quality, promotion and packaging, and associated services (e.g. bulk delivery). These factors in turn depend upon the operational scale, skills, commitment and resources of the compost maker. Only the most sophisticated producers have a chance of meeting the needs of a discriminating market for potting soils in the greenhouse industry. Marketing packaged compost is unlikely to be an economic option for any but the largest producers of high quality compost. Most government and farm composters are best able to produce and distribute small to moderate quantities of low value bulk composts. Because bulk compost markets tend to be poorly developed and transport costs are relatively high, potential revenues for this majority of producers will vary according to the compost's local and regional competitiveness with substitute products.

In the common case that no good paying market is established for finished compost products, on-farm composting can still earn revenues through disposal fees. With the growing prominence of environmental concerns and the attendant crisis in waste management, a major new economic incentive to compost is emerging. Composting offers an environmentally benign way to divert a significant portion of the municipal solid waste stream out of costly landfills or incinerators. Trash tipping fees/disposal costs in the neighborhood of $50 to $100 per ton are becoming common, and these costs will continue to escalate. Organic waste generators, or those ultimately responsible for disposing of waste, therefore have a strong interest in the development of alternatives like composting.

This economic fact has been the single most important factor in the increased attention given to composting in recent years. It is for this reason that ever increasing numbers of local governments are deciding that composting offers the most sensible and economic way to manage their organic wastes, particularly their large volumes of leaf and yard wastes and their sewage sludges.

These primary financial advantages of composting - generating revenues by charging waste disposal "tipping" fees and through compost sales - would appear to offer new income opportunities to farmers. While many local governments have begun in-house composting operations, others prefer to turn over their compostable wastes and part of their avoided disposal cost dollars to compost entrepreneurs (as do certain private generators of organic wastes). Farmers are well-positioned to be those entrepreneurs. Local governments collect leaves, a clean and significant fraction of their solid waste stream, in late fall, shortly before a farmer is most likely to be able to devote time and space to composting. Unlike local governments, farmers already produce and market products. Most farmers would have little difficulty composting given their experience with biological processes and soils, their access to appropriately situated land, and ownership of handling equipment generally suitable for compostable materials. Moreover, many farmers must manage wet or high-nitrogen manures that can be beneficially mixed and composted with organic wastes from municipalities, food processors, and other off-farm sources. Farm land can benefit directly from compost applications, and in many cases farmers will determine that its on-farm value exceeds the net profit that can be made by marketing a low value compost.

A number of farmers already compost manures because their own manure handling options make composting attractive even without the enticement of tipping fees from off-farm waste generators or revenues from compost sales. (In some cases, off-farm sources of straw, sawdust, cardboard, leaves, woodchips, or other materials may be the best source of needed bulking agents.) Although manures are usually and beneficially applied to the land directly, some farmers do not have available cropland to effectively incorporate the volumes generated day after day. Composting converts manures into a substantially less voluminous and more stable form. This may permit more convenient storage and handling, particularly compared to daily spreading - labor and machinery devoted to manure management can be shifted to more convenient schedules. Proper composting also helps farmers avoid the neighborhood nuisance (e.g. odor) and water pollution problems that can result from inadequate manure handling capacity.

Farm Composters

Several advantages of agricultural composting have been sufficient to convince a small but growing number of northeastern farmers to compost significant quantities of organic materials. These farmers have incorporated composting of a wide variety of organic wastes generated on and off-farm into their normal operations. Some own large commercial enterprises; others are small "hobby" farms. A number operate otherwise traditional dairy enterprises; several are organic vegetable growers. Some use all or most of the finished compost on-farm; some produce compost and soil mixes as a primary agricultural product. Many use existing on-farm technology to manage the compost piles; others have invested in specialized compost production equipment.

The experiences of these innovators in the use of on-farm compost production technologies demonstrate the practical potential for many different types of farms to compost successfully. However, a number of false starts and the small total number of existing farm composters balance this potential with caution. Despite escalating landfill fees, bulking agents and the accompanying tipping fee may be difficult to capture -- in several cases, eager farmers have discovered that other inexpensive or free local disposal options for organic waste generators already exist. Many farmers, particularly those distant from population centers, will not have the resources or location to be able to take advantage of the potential for sales in underdeveloped compost markets. And perhaps most importantly, each farmer must look closely at his or her own farm and financial resources to determine whether or not it could be advantageous to adapt space, labor, equipment, and manure handling schedules to begin a composting activity. Even the farmer that has a guarantee of revenues from waste disposers at the front door and from compost buyers at the back door must make sure that his or her costs of composting will not lead to long term losses. The remainder of this chapter will examine more closely the costs farm composters face.

Costs of Composting

Any farmer starting to assess the likely costs of a composting operation should ask a few basic questions. First and perhaps most importantly, what quantity of appropriate organic materials are available to compost, and at what price? Many, if not most farmers have the potential to compost up to several thousand cubic yards of material without significant new costs. Larger volumes require increasingly substantial commitments of land, labor, and/or capital investment.

Second, what kinds of on and off-farm materials are available? Preferable on-farm candidates are uncontaminated organic waste materials that have significant handling or disposal costs whether composted or not. Preferable off-farm materials are those that come with a tipping fee and complement the important physical characteristics (carbon to nitrogen ratio, moisture content, particle size, etc.) of on-farm compostables. Care must be taken to ensure that off-farm materials like municipal leaves or cardboard are free of any contaminants (e.g. metal, concrete, chemicals) that can harm processing machinery or degrade the value of the final product. Nutrient rich, wet farm manures and clean municipal leaves that come with a tipping fee are an attractive combination. Usually, the farmer will not have to purchase any compost "ingredients". However, even on-farm compostables may impose significant additional handling costs if the compost site is not conveniently located.

Third, how much land can the farmer devote to composting? Composting can be land hungry. Farmers serious about composting are likely to want at least an acre of unused or underutilized land with suitable slope, drainage, and access. The amount of such land available, in conjunction with the amount of material to be composted, will be a driving force behind the cost of necessary compost technology. Depending on the technology used, an acre can handle from two or three thousand cubic yards to several tens of thousands of cubic yards of compostables per year. Should scarce land be valued at many thousands of dollars per acre, then sensible farm composters handling significant quantities of material will need to invest in the capital equipment that allows them to minimize their use of land.

Fourth, what are the expected markets or uses for the finished compost? The production of compost to meet the needs of a specialty or high value market calls for particularly rigorous controls in order to keep out or remove incoming contaminants (both physical and chemical). Capital investment in improving the final product through shredding or screening is important. Marketing expertise is also required, along with associated marketing costs. These costs are likely to significantly exceed the costs of applying finished compost to farm land, and many farmers will prefer to simplify their compost systems and take advantage of the benefits of adding compost to their own soils. Much of the expensive extra processing does little to add value to the compost from the point of view of a farm application.

In reality the costs of any particular compost operation depend on a large number of additional specific variables, many of which will vary from farm to farm. An extensive but not exhaustive list of the variables of importance includes the local costs of labor, fuel prices, the value of land and the cost of purchasing and maintaining equipment. The type and volumes of material handled can differ according to the type and size of farm and the character of nearby communities. The choice of compost technology, alternative manure handling practices, and the extent of necessary site preparation depend on farm specific circumstances. Several location factors can have strong influences on costs. These include proximity to neighbors, the distance to off-farm sources of compostable materials, and the distances compostables generated on-farm must be moved first to the compost site or later from the compost site to the point of final use. Further variation can be expected in the need for local or state permits, interest rates and credit terms, the quality of product desired by the end-user, and so forth.

Different factors will come into play at different stages of the compost process. Typically before start-up, the composting operation must be planned, potential markets identified, and any necessary permits obtained. A site must be prepared and any new equipment acquired. Once normal operations begin, materials handling processes dominate. All materials to be composted must be delivered to the compost site: transportation to a compost site on a remote field can be costly even for materials generated on farm. Many materials will require a pre-processing effort that ranges from contaminant removal to particle size reduction including grinding, chipping, shredding or chopping. The materials must be mixed together, ideally approximating a homogeneous mixture with optimal carbon/nitrogen ratios, porosity, and moisture content. Next, or simultaneously, the initial piles must be formed considering the appropriate size, shape and location for the technology used. Routine aeration and/or continued mixing of the piles ensues, with consolidation of windrowed piles as volume reduces. Water may need to be added to dry piles. Some degree of monitoring of the piles is required to ensure that composting is proceeding as expected. The nearly finished compost is normally formed into curing piles prior to any final screening, drying, sorting, mixing, packaging or other preparation for end use markets. Finally, the compost must be stored, spread on farm fields, marketed from the farm or delivered to its final user.

At the economic center of the composting process are the expenditures for the land, labor and equipment that are needed to physically transform the manures and other compostable materials into a stabilized compost product. While there are other costs that may be substantial (e.g. moving compostables to the compost site), it is the costs of managing the compost piles themselves that are most distinctive to compost operations. Fortunately, desirable composts can be produced using technologies or management systems that employ different combinations of land, labor and equipment, thus allowing the farmer to emphasize use of the factors least costly to him or her. As suggested earlier, more intensive (and expensive) management systems are able to handle more material in a given land area, largely by increasing the speed of stabilization and volume reduction and decreasing the time required to produce finished compost. Thus, as volumes of material to be composted increase, the tendency is to increasingly devote a greater proportion of total production costs first to increased labor and then to more sophisticated composting equipment.

Depending on the scale of operation and the technology adopted, initial outlays for site preparation, planning, and permitting, plus any other investment in equipment and the site, can range from a few hundred dollars to hundreds of thousands of dollars. Existing municipal compost operations report costs of production from several dollars per ton to more than a hundred dollars per ton of compostable material. Farmers, who must employ similar technologies, face a similar broad range of costs. Though very large quantities of material and materials that are relatively difficult to compost without problems often require a more costly management system, the greater expense buys substantially greater annual production capacity. A key to minimizing costs per ton is scaling the operation to make possible the efficient utilization of costly fixed investments like specialized composting equipment or land.

The Costs of Five Composting Approaches

Given that the compostable materials at hand have been mixed in appropriate proportions, there are at least five basic approaches to sustaining the conditions that support the micro-organisms doing the main work of composting:

  1. First is a static pile approach requiring little or no active management of the pile after initial mixing.
  2. The second approach, turning windrows with a loader, is possibly of interest to the largest number of farmers. This approach minimizes new investment through the primary use of land and capital already owned, thereby making possible management of composting windrows at a relatively low level of management intensity.
  3. Third, the farmer may manage windrows at a moderate level of intensity through the purchase of equipment, particularly specialized windrow turners, substantially or completely dedicated to composting.
  4. Fourth, aerated static pile systems may be used. These depend on forced air blowers rather than mechanical pile turners to aerate piles that, since they are not mixed further, should be especially well-mixed and porous to begin with.
  5. Fifth, a few farmers may consider highly capitalized high intensity management approaches that minimize the use of land and labor. These approaches include a variety of in-vessel systems that use forced air and/or mechanical agitation to aerate wastes in the confines of an enclosed bay or vessel. While expensive, such systems offer highly controlled environments which significantly enhance the operator's control over the process and his or her ability to optimize conditions for composting. The time required to produce compost can be reduced to as little as two months.

Few working farms' compost operations have been carefully analyzed to isolate farm specific costs of producing compost. However, the partial information available from research, farm, private and municipal operations makes it possible to estimate the approximate costs of farm composting using these different approaches. Reviews of the composting approaches, based on controlled studies and the experiences of cooperating farmers, are discussed below.

Alternative 1: The Static Pile Approach for Very Small to Moderate Sized Operations

Farmers using this approach form piles of organic materials and then let them sit until the materials have degraded into a stabilized product. Because there is no further mixing or active aeration, the piles are likely to degrade under undesirable odor-producing anaerobic conditions. Although piles should be monitored and must be formed and well-mixed to begin with, the costs of labor and capital devoted to actively "composting" the piles are essentially eliminated. However, the time required to produce a stable compost may be a year or more, particularly if the mix and particle size of the compostable materials significantly diverge from the ideal. The consistency and quality of the final product is likely to be variable. Overall use of labor and equipment is kept to a bare minimum. This option is most likely to make sense for farmers that have suitable available land and relatively small volumes of compostables that can be left on that land.

Alternative 2: The Loader-Turned Windrow Approach for Small to Moderate Sized Operations

The Loader-Turned Windrow approach is very similar to the static pile approach, and again assumes no additional equipment or investment, as well as volumes of material likely to range from a few hundred to several thousand cubic yards per year. The key difference is that the piles are actively managed (i.e. turned) with farm equipment. This equipment would normally consist of a tractor with bucket loader or a tractor, loader and manure spreader combination.

Good initial mixing at the time of pile formation helps establish conditions which minimize the need for further active pile management. Costs of composting with this approach are further minimized by attempting to use the turning equipment during slack times for other farm chores. The incremental costs of pile management are then effectively added to the costs of pile formation and mixing discussed for the static pile approach. Despite greater costs, turning and mixing the piles even a few times per year will hasten volume reduction and material decomposition while improving the quality of the final product. Judiciously timed turning can reduce the likelihood of problems (e.g. odor) associated with anaerobic decomposition. Since the amount of time that farm labor and equipment must be diverted from other tasks can be significant, the smaller the total volume of material composted, the more frequently it is feasible to turn the windrows. It can take several days to turn moderately large piles of several thousand cubic yards. Turning piles three to five times during the year seems typical for yard waste based operations of this scale. However, the frequency of turning may need to be increased to control odors if nitrogen and moisture laden materials like manure or grass are not mixed with sufficient bulking agents.

In addition to scores of local governments, there are a number of active farms in the Northeast that use this approach. The few documented examples include an organic grain farm which handles spent mushroom compost, a hog farm, (Dreyfus 1990) and a dairy farm (Rynk 1989). Even operations that have invested in specialized windrow turners often use standard machinery as a back-up.

What does it cost to turn and mix piles using standard farm equipment? The power and size of the equipment used obviously make a difference. Efficient municipal front-end loaders take roughly a minute to go through a simple load, dump and maneuver cycle (Caterpillar, 1989), and farm loaders (tractor or skid steer) appear to be capable of similar performance. However, buckets on farm loaders are often much smaller (1/3 to 1 yard capacity), and therefore significantly slower at turning piles, than the two to five yard buckets normally used by municipal composters. The costs of turning and mixing also will depend strongly on the character and bulk density of the materials being turned, as well as the turning technique and the thoroughness the operator tries to achieve with each new turning.

Dreyfus (1990) compared the costs of two turning techniques. First, a farm tractor with a 1 cubic yard front loader was used for turning leaves alone. Second, the same loader was used to dump the leaf compost into a manure spreader. Use of the manure spreader allowed for more thorough remixing and pile reformulation. Both systems were limited by the loader capacity of 70 cubic yards (14-18 tons of leaves) per hour. If a significantly larger bucket had been used, the limiting factor would have been the capacity of the manure spreader rather than the loader. The cost of turning the piles once was estimated at between $1.50 and $2 per ton of leaves with the loader alone, and double that (because two tractors were needed) for the cost of the loader/spreader combination. Comprehensive costs of owning and operating each 100 hp tractor were $30 per hour (as per Fuller and McGuire, 1988). Of course, many farmers operate smaller and less powerful tractors at lower hourly rates.

In a related study of different materials, Gresham, et. al. (1990) also reported costs of using a front-end loader to load a tractor-drawn manure spreader that then mixed and reformed the piles. Those costs range from $1.12 per ton for poultry litter (processed at a rate of about 2 minutes per ton) to $3.75 per ton for a litter/shredded newspaper mix (processed at a rate of about 7 minutes per ton).

In another example, a Cornell University researcher used a 40 hp tractor with a 1/3 cubic yard bucket to compost 100 tons (approximately 300 cubic yards) of bull manure and sawdust bedding. The equipment was able to turn about 20 cubic yards of material per hour. Many farmers have tractor loaders or skid-steer loaders that would have similar or somewhat greater turning capacity. At a rate of $15 per hour for labor and equipment, the per ton cost of turning only was $2.25 (Richard 1991).

Calculations based on Cornell University Farm Services' composting of animal manures plus bedding suggest much less expensive turning is possible with farm equipment under the right conditions. A one yard bucket with manure tines on a $50,000 tractor including loader attachment managed to pass through about 300 cubic yards of bedded manure in just over an hour (about 75-100 tons per hour!) using a turn and roll technique. Although this technique is inherently limited in its ability to remix and aerate piles, this consideration was minor because a specialized windrow turner was normally available at the site. At the $30 per hour cost including labor of owning and operating the tractor (Tennant 1991), this turning style translates into costs of only about $0.30 to $0.40 per ton of manure.

An important factor to keep in mind is that the volume and weight of incoming material decreases rapidly when composted, particularly in the first months after initial mixing. Eventual reductions in volume depend on the materials involved, but 50-80% reductions are normal. This is significant because it means that second and subsequent turnings of a pile should be substantially less expensive and time consuming than the initial turning. Richard (1991), for example, calculated that the sum of 3 subsequent passes (at 3 month intervals) through the bull manure only took 1.5 times as many hours as the first turning, implying total turning costs of $5.63 per ton of incoming manure. While there may be good reasons (e.g. odor control) to thoroughly mix and aerate a pile frequently after initial pile formation, the composter can reduce costs by waiting to turn piles that are shrinking rapidly anyway.

Data from municipal leaf compost operations suggests that a similar low intensity compost management approach (using a municipal front loader when available to turn piles three or four times a year) usually costs municipalities close to $5 per ton of incoming material, including full equipment, land and labor charges. Costs directly associated with pile turning and formation usually account for 80% or more of this per ton cost.

This information suggests that turning piles using a loader will add several hundreds of dollars to the cost of a small compost operation. Farmers with larger operations handling on the order of 500 tons of material a year are likely to add to costs by several thousands of dollars. However, most of this cost will be paid not in cash, but in hours the farmer is not devoting to other tasks and in an accelerated depreciation or repair schedule for farm equipment.

Alternative 3: The Specialized Equipment Approach for Moderate to Large Windrow Operations

As the volume of material to be handled increases, composting tends to become a central rather than an add-on farm activity. The compost operation demands more land, more equipment, and more labor. As the demand on these resources begins to interfere substantially with other farm activities, most farmers invest in additional capital equipment dedicated to the composting operation. Additional hired help may also be needed. While an intermediate step in this direction is to invest in larger equipment that has other farm uses, a number of farmers facing this choice have also invested in specialized windrow turners. Municipalities effectively utilizing this basic approach on large volumes of yard wastes have reported overall costs in the range of $15-30 per ton of incoming material.

The specially designed windrow turners have several advantages over standard farm equipment. Each of several turner designs does a better job at mixing and particle size reduction than does a front loader or even a loader and spreader combination. Most windrow turners do a reasonably good job at reforming the windrow shape automatically, though they tend to be less versatile than are loaders in handling oversized piles. Most importantly, windrow turners can substantially reduce the amount of time that must be spent turning piles. Since most farmers use tractor powered or towed windrow turners, this means that more tractor and operator time can be spent on other farm chores. (Nevertheless, a loader will still be required for initial pile formation, pile maintenance, and other tasks such as feeding a compost screener or shredder.) Of course, all PTO-powered turners must be matched appropriately to the farm tractor in terms of power and minimum traveling speed, which may require a creeper gear, special drive, or a second machine and operator to tow the tractor powering the turner.

The smallest PTO-driven windrow turners can process roughly 200 tons of material per hour at a capital cost of around $10,000. Larger windrow turning machines, including self-propelled models, can process two thousand tons or more per hour. Most of the larger windrow machines that can process thousands of tons per hour cost $75,000-$200,000.

Table 1 and Table 2 highlight in overview the implications of the type of composting equipment used for the overall cost and amount of time an operator and equipment will spend turning incoming material. In these hypothetical examples focused strictly on turning or aeration of piles, volumes of incoming material range from a modest 1000 cubic yards to a substantial 15,000 cubic yards a year. In the examples, the amount of time required to turn the material four times a year ranges from 187.5 days to less than an hour, depending on the amount of material and the capacity of the aeration/turning equipment (Table 1). All of the windrow turners can handle up to 15,000 cubic yards of incoming material in about 12 days of time or less; the largest one considered would scarcely need to be warmed up to manage even 15,000 cubic yards. The loaders could each handle the 1000 cubic yard windrows in a time of two weeks or less, but would take a significant additional amount of time to manage larger piles. In reality, it is likely that anyone who had invested in a windrow turner would turn the piles more frequently than four times, further accelerating the composting process to free up land and market or use the product more quickly. Similarly, the small tractor or skid loader operator would be unlikely to want to spend the time required to turn the 5000 or 15000 cubic yard piles even four times.

Table 1. Reported costs of turning windrows with bucket or front-end loaders.

Turning equipment/technique Materials Capacity (cubic yards per hour) Turning cost per ton
100-horsepower tractor with 1-cubic-yeard bucket loader Leaves 70 $1.50-2.00
100-horsepower tractor with 1-cubic yard bucket loader plus manure spreader and second 100-horsepower tractor Leaves 70 $3.00-4.00
Front-end loader (22.5 cubic feet) plus manure spreader and tractor Poultry litter 42 $1.12 a
Front-end loader (22.5 cubic feet) plus manure spreader and tractor Poultry litter and leaves (1:1) 37 $1.25a
Front-end loader (22.5 cubic feet) plus manure spreader and tractor Poultry litter and newspaper (1:4) 15 $3.75a
40-horsepower tractor with 1/3-cubic-yard bucket loader Bull manure and sawdust bedding 20 $2.25 b
Sources: Dreyfus, Gresham et al, Richard

a Assumes equipment owning and operating costs of $30 per hour (1988).
bAssumes equipment owning and operating costs of $15 per hour (1990).

Reprinted with permission from On-Farm Composting Handbook. Published by NRAES. (607) 255-7654.

Table 2. Time and costs of turning windrows four times annually

Incoming material
1,000 cubic yards 5,000 cubic yards 15,000 cubic yards Assumptions
Equipment Total cost Hours Cost per cubic yarda Total cost Hours Cost per cubic yarda Total cost Hours Cost per cubic yarda Capital costs Hourly operating costs Processing capacity (CYH)b
Small loader (40 horsepower); 1/3-yard bucket $1,423 100 $1.42 $6,398 500 $1.28 $17,276 1,500 $1.15 $15,000 $10 25
Tractor (85 horsepower) and $6,000 loader attachment; 1-yard bucket $1,116 33 $1.12 $4,800 167 $0.96 $11,669 500 $0.78 $45,000 $13 75
Front loader (135 horsepower); 3-yard bucket $3,062 11 $3.06 $11,365 56 $2.27 $21,135 167 $1.41 $130,000 $22 225
Windrow turner (small, PTO-driven) with 40-horsepower tractor $2,326 6 $2.33 $2,885 31 $0.58 $4,205 94 $0.28 $28,000 $13 400
Windrow turner (large, PTO-driven) with 100-horsepower tractor $4,383 2 $4.38 $4,551 10 $0.91 $4,996 31 $0.33 $65,000 $19 1,200
Windrow turner (medium size, self-powered) with 80-horsepower tractor tow $17,360 1 $17.36 $17,491 3 $3.50 $17,797 9 $1.19 $115,000 $32 4,000

Note: Operating and ownership costs are included. Turnings are assumed to be timed such that 2.5 times the incoming volumes are turned after accounting for shrinkage. Total compost turning hours are calculated by dividing the total volume to be turned by the assumed hourly processing capacity of each machine and, therefore, assume maximum efficiency with no breaks. The proportion of total hours of farm use attributable to composting is calculated by dividing turning hours by the sum of turning hours and typical hours of farm equipment use reported for each type of equipment in New York farm survey data. Ownership costs are annualized over ten years assuming 11.5% interest rates and 40% salvage values. Insurance and storage are assumed to be 2% of the purchase price annually. Operating costs assume $6.50 per hour labor for tractors. Other hourly operating costs are based on long-term rental rates or derived from O&M data provided by equipment manufacturers or New York farm survey data.

a Multiply costs per cubic yard by 4 or 5 for per-ton costs for leaf composting; less for denser materials. bCYH stands for cubic yards per hour.

Reprinted with permission from On-Farm Composting Handbook. Published by NRAES. (607) 255-7654.


The amount of material loaders can process per hour is more or less proportional to the size of their buckets. Thus, a farmer increases the turning capacity of a tractor or skid loader with a 1/3 yard bucket ninefold by using a front loader that can support a three yard bucket. However, few farmers own tractors that are designed to handle attached loaders of more than about 1 cubic yard capacity. The capital cost of a large municipal style front loader is roughly 9 times that of a skid loader or small tractor with a loader. Achieving the ninefold increase in capacity would thus require an investment in equipment that costs more than the total value of machinery and equipment owned by most (NY dairy) farmers (Milligan et. al. 1991). Of course, buying used equipment would reduce up-front capital outlays significantly. While a front-end loader does have many other farm uses (including for composting tasks other than aeration), only a large farm with a large compost operation would be likely to invest in such a costly and relatively specialized piece of equipment.

Table 2 reduces a number of the trade-offs between time, labor and equipment use to a common cost denominator. Each approach to pile aeration becomes less costly on a per unit volume basis as the volume of material increases and equipment is more efficiently utilized. As expected, none of the specialized windrow turners are competitive economically if small volumes of material are to be turned. As the amount of material to be turned increases (either through more incoming material as assumed in the example or due to more frequent turning), the windrow turners become increasingly competitive; at 15,000 cubic yards per year the small PTO driven turner is the least costly approach per cubic yard, and the self-powered windrow turner is no longer the most costly. The economies of scale are not nearly as great for any of the loaders. However, the skid loader and tractor loader are the most cost effective turning approach at small volumes and remain relatively inexpensive per cubic yard as volumes increase. This is because variable operating costs are low and the modest capital costs continue to be spread over other farm activities. The perhaps unrealistic assumption that the expensive front loader has few other farm uses dooms it to a poor showing in comparison with most of the other equipment.

Two northeastern farm composters provide quite different real world examples of the Intermediate Management Intensity farm compost operation. Gerster Farm is a large dairy and pig farm that has incorporated a composting activity into traditional farm activities; Moody Hill Farm is an organic vegetable producer that specializes in manure removal services and the production of compost for sale. Gerster mixes bulking materials from off-farm into its animal manures, while Moody Hill collects manures and other materials from off-farm to produce compost. Both help support their compost operation by charging fees for handling the off-farm materials. See the Case Studies section for details about each of these operations.

Alternative 4: Farm Composting Approach with Static Pile or In-Vessel Systems

The scarcity of land to manage high volumes of manures, the need to strictly control environmental impacts (c.f. proximity to neighbors or streams), a desire to minimize labor involvement in a large operation, and the advantages of producing a product of more consistent quality provide the major incentives to consider a higher intensity composting approach ( Walker, et. al. 1989). Several technologies provide the controlled environment that helps sustain optimal composting conditions, reduce smells and run-off and increase annual capacity. Municipal experiences with aerated static pile systems give evidence of costs in the $20-50 per wet ton range. Some of the more expensive municipal in-vessel systems report costs as high as $150 per ton (Richard, et. al 1990).

Aerated static pile systems are being used to compost a number of organic materials. Included among the wastes most commonly treated this way are municipal sewage sludges and processed (e.g. finely ground) food wastes. These materials are fairly wet and uniformly textured, and can be easily mixed with bulking agents like wood chips or sawdusts with appropriate properties (e.g. particle size). The bulking agent may need to be purchased. Because aerated static pile systems depend upon forced-air blowers but no mechanical mixing to maintain air flow through a compost pile, they are best suited to materials like these that can be thoroughly mixed when the pile is formed and that maintain structure and porosity throughout the process. Typically, in order to improve air diffusion, prevent drying at the core, and to maintain an even temperature throughout the pile, the actively composting material is sandwiched between an outer blanket and an inner core of new or "recycled" chips.

Probably because this system has a comparatively narrow range of tolerance for error or for variability of mixes, there is little successful on-farm experience using these systems with agricultural wastes. Fulford (1987) tried an aerated static pile system with farm manures mixed with cardboard and paper, but due to the lack of structure in the bulking material, the piles compressed and had to be turned. One large commercial producer of composts and soils "found, for various animal manures, that the aerated pile system did not produce the quality dry product" it required for a bagged compost that could be sold as a dehydrated manure product (Kuter 1987). Also, costs of aerated pile sludge treatment systems have been estimated to achieve optimal economies of scale at systems treating 60 or more dry tons of sludge per day, an amount that might be generated by a city of 600,000 (Colacicco 1982); such systems were reported to require a capital investment of $30,000-$38,000 per dry ton-per-day (in 1977 dollars). A much smaller indoor sludge compost system capable of handling the waste of 3,000 people (450 gallons of sludge solids per week) might require $150,000 in specialized capital investment (blowers, piping, controllers, structure; not including land, loader, screener, etc.), and maybe a tenth that cost in annual operation and maintenance costs (Romeiser 1991). A simpler outdoor system on a prepared surface could cost less. Brinton and Seekins (1988) designed a very small (50 cubic yard) aerated pile test system to compost fishery wastes mixed with sawdust, horse stable bedding, wood chips and other bulking agents. They estimated annual owning and operating costs of such a system scaled to manage 200 tons of fish waste annually. A system cost of $2,661 per year includes use of a machine to mix materials, a loader to form piles, and an electric blower (335 cubic feet per minute) to force air through 4" perforated pipes, but excludes costs of transportation, purchase of bulking agents, and land and site preparation. The $2,661 translates into $13.31 per ton of fish wastes composted. The cost per ton including bulking agents would be less. Farmers with suitably uniform materials might well find a simple system like this to be cost-effective.

The agitated bay in-vessel systems appear to have the most promise for the heterogeneous manures and bedding materials likely to be involved in farm composting - a handful of farms around the country have already invested in them. A number of vendors manufacture the large systems on the scale of 200 ton per day facility (or larger); the choice of small systems (e.g. 20 tons a day or less) likely to interest the majority of farmers is less, though commercial and unique home-built systems have been installed.

The basic agitated bay technology is conceptually similar to a windrow technology - an agitating machine moves through piles of manures and other wastes, mixing, chopping and aerating as it passes through. However, enclosing the composting materials in a bay allows a machine moving on a track to replace the windrow turning machine and operator. Automation permits more intensive agitation, and the period of active composting in the bays can be reduced to about a month. Enclosing the bay in a structure also helps further control or eliminate environmental impacts, both in terms of variable inputs to the compost mix (e.g. rain) and unwanted outputs (odor or runoff). Systems capable of handling approximately 20 - 40 cubic yards of material per day range from about $100,000 to $175,000 in capital costs, including agitators, structure, site grading, concrete and other costs (Allen, 1991).

This generic economic analysis provides an overview of the range of options available to farmers and the relative costs and economies of scale. A more detailed, individual look at agricultural composting enterprises is provided in the following section.

Case Studies in Agricultural Composting

Case studies are related for each farm originally slated to be part of the project (the Amar Farm, Kreher's Poultry Farms, Moody Hill Farms, Rose Valley Farm, and Seneca Foods), those which later joined the project (Cornell Farm Services, the Earth Works Farm, Gerster Farms, and Hardscrabble Farm) and a few other compost operations thought to be of interest to farmers or food processors in New York State. Each case study includes information on composting technology used and processing experiences. Some case studies briefly describe what went "wrong" at the farms which did develop or continue their agricultural composting efforts. Three of the cases include a detailed economic analysis of capital and labor requirements: Gerster Farms, Moody Hill Farms, and Rose Valley Farm.

Amar Farm

This farm did not participate in a detailed case study since they did not ultimately enter the composting market. The Amars purchased and rehabilitated a composting turning machine and intended to offer turning services to municipalities in their region. There initially seemed to be municipality interest as part of their solid waste programs. The Amars needed funding to construct a trailer to move the machine around Chenango County and adjoining areas. They were unable to obtain trailer construction funding or contracts to provide this service. The municipalities' interests had turned to pressing questions such as landfill siting and they were not so eager for composting and the available contract turning services the Amars offered. The Amars worked with Cornell Cooperative Extension of Chenango County in organizing this municipal compost turning business. One of their objectives was to give municipalities experience in operating compost facilities without a major equipment investment and to demonstrate the worthiness of the composting process in municipal solid waste handling. Presently, there is no active farming at Amar Farm and the turning machine is unused.

Anheuser-Busch

This brewery operation in Baldwinsville, New York has been composting the solids from their wastewater treatment facility since 1989. They selected an in-vessel system which processes approximately 15 dry tons a day of this food processing sludge, which is combined with sawdust. Trials with peat moss and shredded phone books have also occurred, and phone books and other waste paper materials are likely to be included on a regular basis if regulatory approvals are received. This facility is currently exempt from the NYSDEC solid waste permitting requirements because the sludge is classified as a food processing waste, but they do have an air emissions permit and have constructed a biofilter of compost and woodchips to filter the building air. Details of the composting operation and tipping fee savings are provided by Beers and Getz (1992). In the first two and a half years of operation over three million dollars in landfill fees were avoided. The finished compost is marketed by AllGro. Inc., a regional compost distributor.

Cornell Farm Services

A confluence of factors brought Cornell to develop an agricultural composting operation in 1990. Farm Services, the unit responsible for most of the manure and vegetative waste management, had been land-applying these materials on approximately 700 acres of cropland. Seasonal constraints on application required stockpiling, and concerns with water quality and nuisance impacts from the storage forced a reevaluation of alternatives. Composting had already been successfully used on a pilot basis for greenhouse plant and soil wastes, so the staff had a general familiarity with the process. After an extensive search a site was identified and developed to complement the ongoing land application program.

The initial site was expected to be temporary, based on both neighborhood concerns and the distance from the manure sources, so development was minimal. A gravel roadbed was installed for access to the site, but no further preparation was attempted on the well drained soils of the active composting area. A specialized compost windrow turner was provided on loan from SCAT, and a tractor with loader was available from Farm Services to propel the machine and shape the windrows as necessary. This initial operation, relying on borrowed equipment and minimal investment, has been reasonably successful and a permanent site is currently being developed. The permanent site will include an improved working surface of gravel or possibly oiled stone to improve year round trafficability which was a problem on the native soil of the original site.

The composting operation is run in cooperation with the host town of Dryden, which brings grass clippings and leaves to the site on an occasional basis. Cornell's Grounds Department also brings leaves for composting in the fall, and trials have been held with food wastes from the Cornell cafeterias. The main bulk of the material is manure and bedding, which averages two to three manure spreader loads per day. Much of this manure includes large amounts of bedding, either from horse operations or veterinary research, so additional amendments are not required. As staff gained experience with different composting mixtures, materials such as produce from vegetable trials, greenhouse wastes, and paper bedding have been successfully incorporated. The compost is used in a wide variety of application, including Cornell grounds and cropland. A significant fraction is distributed free to neighbors of the composting site, which has helped insure local community support.

The Earth Works Farm

The Earth Works Farm is a crop farm located on the shores of Cayuga Lake. The farm currently produces mostly hay, which is marketed regionally. The Earth Works is an organic farm, and without any animals or chemical fertilizer inputs, composting is considered important to maintain and improve soil productivity. The major source of off-farm organic matter has been aquatic weeds, which pose a major nuisance to recreational use of the shallow waters at the north end of Seneca Lake. Lake weed harvesters collect this material and is delivered to the farm under a contract with the Soil and Water Conservation District. Fresh aquatic weeds are allowed to drain and then mixed with old compost or moldy hay.

The composting operation uses available farm equipment, including a manure spreader to mix and form windrows and a tractor with front end loader to load the spreader. This is an approach which is described in greater detail in discussion of Rose Valley Farm below. When the compost is finished, the same equipment is used to spread the material on cropland. Ros Parks, the farm owner/operator, is planning on converting a unique old snow remover he has acquired into a windrow turning machine to minimize space and labor requirements.

Gerster Farms

The daily 4-5 hour chore of manure spreading, an inability to obtain cost sharing for a manure storage system, and the prospect of earning tipping fees from local governments convinced Gerster Farm to consider composting. After spending about 650 hours in planning over an eight month period, the 300 head dairy farm began a pilot composting operation in September of 1990. Initially, dairy manures and straw bedding were mixed for composting with a fine sawdust residue from pressboard manufacture. Within a year, the farm had added 400 pigs (fed partly with dairy product wastes from a nearby processor), cut the dairy herd size by 100 cows and added cardboard and shredded paper to the bedding and compost mix. Details of the financial implications of this level of operation are provided in Table 3. The farm has also applied for a permit to accept yard wastes from off-site and offered to accept yard wastes from municipalities for $25 per ton, but none have yet accepted this deal. Purchase of a $150,000 tub grinder to process cardboard boxes, woody materials and leaves for bedding is being considered. In continuing evolution, planning is also underway for a 200 ton per day in-vessel composting system capable of handling manures and bedding from thousands of pigs, and possibly sewage sludges or municipal solid wastes.

Table 3. Gerster Farm.
Task Monthly
farm
labor
(hours)
Monthly
farm
machine
time (hours)
Comments
Initial site preparation (one-time expense)a
360b
360b
Dozer, loader, truck used
Manure removal from barns
30
30
Used 5-yard bucket loader
Pile formation, chopping and mixing materials
Mixing and pile formation only
Cardboard and chopping only
90
25
65
90
25
65
Used chopper & loader
Used loader
Used chopper
Pile turning
17
17
Used dozer and turner
Field spreading when not composting
150
150
Used slurry spreader
Field spreading of compost
2
2
Used loader, spread at 1 inch

aEstimated local land value is $1,500 per acre.
bOne-time expense.

Materials
Compostable materials Notes Est.
quantity
(tons
per
month)
Special
handling
Farm
labor
involved
(hours
per day)
Revenue
per ton
On-farm
Dairy Manure
Pig Manure

No bedding, 200 cows
No Bedding, 400 pigs

350c
80c

Manure removal
Manure removal

1
1

-
-
Off-farm
Cardboard
Shredded paper
Cellolose powder

Used for bedding
Used for bedding
From pressboard

55
20
7

Chopping
Use as is
Use as is

2
-
-

$30
$30
$30
Total
512
Note: Because of composting, mulch hay purchases of 8­10 tons per month at a cost of $50 per ton were avoided.
cEstimates based on data from the American Society of Agricultural Engineers.

Compost/manure-handling equipment
Equipment Model and
features
Cost Year
purchased
Notes
Front-end loader Michigan 175B, 5-yard bucket $15,000
1975
Replaced by loader below
Front-end loader International H-90, 5-yard bucket $30,000
1991
Vintage 1984
Windrow turner, tractor tow model Scat 482B $56,000
1990
Vintage 1990
Track dozer for turner tow John Deere 450G $30d
-
-
Slurry type spreader Gehl 7-ton capacity $14,000e
-
-
Corn chopper with hay head Gehl 860 $16,000f
-
-
Tractor (85-horsepower) Case International 5130 $48,000f
-
-


dPer hour rental.
eEstimated 1991 new value for 2,400-gallon capacity. Actual costs not available.
fEstimated 1991 new value. Actual costs not available.
Reprinted with permission from On-Farm Composting Handbook. Published by NRAES (607)255-7654.

On-site preparations for the composting project began during three weeks of full time work in August 1990, when a one acre site ($1000-$1500 value) of underutilized land adjacent to the dairy barn was graded and surfaced with topsoil and gravel from small rises at the edge of the site. The slope was later regraded to improve drainage off the site. The acre of land is sufficient to manage the estimated more than 500 tons of manure and bedding per month generated by the 600 animals currently on the farm. The wet manures and bedding are bulked with additional cardboard, paper and cellulose powder. The paper and cardboard materials are delivered daily to the farm in county collection trucks and the wood fiber is delivered every other month by the pressboard manufacturer. Each is charged a $30 per ton tipping fee.

As in the past, it takes about an hour of labor each day to clean out the barns and dump the manures in a pit with a 5 yard bucket on a front loader. However, instead of spending another 4-5 hours on 6 or 7 trips a day with a slurry spreader to spread the manures on a field 1.5 miles distant, an average of about 3 hours a day are devoted to compost related chores including chopping cardboard in a corn chopper for bedding, blending the bedded manures and additional bulking materials in the mixing pit with the loader, and forming windrows of the mixed material with the loader. Of these hours, only the mixing and windrow formation work, which actually takes about 2 hours of time every three days, is completely new. Prior to beginning the composting operation, the farm was already putting a couple of tons of mulch hay a week through a bedding chopper. Now, cardboard is being chopped but instead of paying the $50 per ton cost of mulch hay, the farm receives the tipping fee for the cardboard and shredded paper.

Unfortunately, the chopper is not well suited for the cardboard (staples and all), and down time, machine wear, plus labor time are a costly part of this system (c.f. Fulford 1987 for similar conclusions). Since the farm is exempt from solid waste regulations because the cardboard is used for bedding purposes, there is an incentive to continue chopping and using the cardboard rather than incorporating it into the windrow unchopped - where the windrow turner would soon tear up the soggy cardboard (Fulford 1987). However, plans to increase compost volumes in the future will help justify investing in a tub grinder, and mean that the better suited machine can take over this task (a brief site demonstration of the grinder produced enough chopped material to relieve the farm of chopping for some weeks).

An additional four hours per week that are added by the composting operation is spent turning the piles with the windrow turning machine. The $56,000 windrow turner is self-powered but designed to be towed by a slowly moving tractor. In this case a rented track bulldozer is used for towing. The dozer costs $30 per hour of use, but is kept permanently on the farm. While the purchase of a used loader and rental of the bulldozer have reduced initial capital outlays, the cost of purchasing all new equipment (loader, bulldozer and windrow turner) currently used primarily for the compost operation would be approximately $250,000.

All of the finished compost is intended for use in building farm soils. After composting from fall to early spring, the first compost was spread in 1991 on several acres of corn fields to a depth of one inch. Spreading the compost, derived from about 1.5 months accumulation of manures and added materials, took not much more than an hour with a loader. Thus, in comparing the monthly hours devoted to slurry spreading (120 to 150 hours) with added time for compost mixing, turning and spreading chores (40-50 hours, including only part of the cardboard chopping time necessary to produce bedding), it appears that substantial labor time can be saved. Moreover, in a very dry year early plant growth in the field to which compost was applied was visibly greater than in nearby fields, and weeds were few. The farm hopes to eventually eliminate its herbicide use by using compost ($3200 was spent for 115 acres of corn in 1990).

Glaum Egg Ranch, California

One of the smaller farms that has chosen the in-vessel composting option is Glaum Egg Ranch. Prior to composting, manures were sold seasonally as fertilizer and during winter the manure was spread three times a week, causing odor problems. Now the manures from 80,000 birds are mixed year-round with spent mushroom compost (red oak and cotton seed) from an exotic mushroom business. The mushroom compost is available for the cost of hauling. (Of other available inexpensive bulking materials, only rice hulls and apple pulp have also been found to have suitable properties that complement the manure). Approximately 10 yards of manure are mixed with 10 yards of spent compost on a daily basis. A tractor and 1.5 yard bucket loader are used to mix and then roll the mixture into the bay in a process that takes about 3 hours a week. The two bays are 210 feet long by 10 feet wide, and the material is piled to a height of about 3 feet. Material is resident in the bays for a 30 day cycle, and reduces in volume approximately 50%.

The compost structure is "greenhouse-like" with partially open sides and ends, and is located in an area with neighbors who would notice problems. A misting system with an chemical odor suppressant is used to ensure that neighbors do not notice. The 1.5 acre site is on a hillside, and required substantial grading work. Capital cost of the basic system was approximately $80,000. An additional $20,000 was required for the structure, grading and landscaping.

The finished compost is marketed with a strong demand from organic farmers. The compost brings in $15 per cubic yard in bulk, or $25 per pickup. This contrasts with a price of $3.50 to $4 per cubic yard the farm has received for fresh manure in the past. Like several other larger poultry manure composters in the country, the farmer plans to begin a bagging operation. After a significant marketing effort, these other bagged poultry composts have been competing in a wide variety of retail fertilizer outlets at a price of $1.50 per 25 pound bag.

Hardscrabble Farm

This composting operation was developed for the specific purpose of reclaiming an abandoned gravel mine. The 20 acre hillside mine area, located in Ithaca, New York, has been composting since 1987. The mine areas had been stripped of 10 to 60 feet of soil, and the underlying gravel deposits supported little growth. The owners developed a cooperative program with Eastern Artificial Insemination, a dairy breeding program also located in Ithaca. Eastern is in the midst of a decade long relocation of their animal housing from an area under high development pressure to a more rural location, and had to haul their manure across town to cropland at the new location. Hardscrabble, being closer than the new Eastern cropland, proved a convenient unloading location.

The composting site was exempt from NYSDEC regulations since only manure was being composted. However, Hardscrabble was required to obtain approval from the county environmental health department which was concerned about possible runoff issues. A monitoring program was implemented, which indicated that the high wood shavings content of the manure bedding mixture effectively retained nitrogen and minimized groundwater concerns. Berms and collection ditches were installed to minimize surface runoff from the site, as that runoff could contain high BOD levels (Rymshaw et al., 1992).

The two acre site is on a compacted gravel base left over from the mining operations, and provides excellent year round trafficability. Manure is hauled to the site in enclosed dump trucks which unload in approximate windrow shapes. Annual deliveries average 300 to 500 tons, with the balance continuing to go to Eastern cropland as before. The manure is heavily bedded with wood shavings, and both moisture and C:N ratios are within acceptable bounds. The windrows are shaped and occasionally turned by a tractor with a front-end loader. Turning frequency has dropped since the project was initiated, from four times a year to once. With more frequent turning, compost was ready for use after approximately 1 year while the minimal turning approach requires about two years. When it is finished the compost is spread and incorporated in the mineland areas. Vegetative growth has improved dramatically, although the soil-building effort is expected to continue for several more years.

Healing Springs Farm

In 1990, Matthew Shulman of Healing Springs Farm entered a joint agreement with the Town of Lansing and two landscapers (Evan Perrin and Dan Feingold) to compost leaves. The plan was for the town to provide bags and promotion for a fall leaf pickup. The landscapers would collect the bagged material and market the finished compost. Healing Springs Farm would provide the compost site on its 85 acre farm and process the material with an old tractor loader. It was expected that substantial savings would result from not taking the bags the 17 miles to the county landfill. The composters hoped to collect 1-2000 bags. Unfortunately, the plans fell through for the first year when too little material was collected - not enough residents participated in the fall leaf pick-up. The group hopes to improve participation in the 1991 season with a better promotional effort.

Kreher Poultry Farms

The Krehers operate a large egg layer operation in Erie County, New York. Like many poultry operations, they have been under increasing pressure to modify their manure management operations. Their situation is particularly challenging because they are very close to the city of Buffalo, and suburban developments adjacent to their cropland have led to heightened sensitivity.

The composting enterprise was viewed from the start as an economic enterprise. An initial trial with 3000 cubic yards of manure mixed with municipal leaves indicated that yard waste could provide an excellent amendment to the manure from their high rise poultry houses. The Krehers proceeded to obtain a NYSDEC composting permit, which in their case was required because they intended to process more than 3000 cubic yards of yard waste per year. Theirs was the first large scale composting permit in the region, and the process was both exhaustive and expensive. The permit was eventually received, but at that point they were unable to negotiate acceptable contracts with the neighboring municipalities generating large quantities of yard waste. While some small generators expressed interest, the economies of scale required by the Krehers have not been achieved, so their composting program is on indefinite hold.

The Krehers have faced several challenges in their attempt to gain acceptable contracts. Some of the municipalities were able to make more cost effective arrangements with other farmers or nurseries which were willing to take the material at a lower price or free. Nurseries, with a built in need for the compost product, may evaluate the economics of composting from a significantly different perspective than a farmer with organic matter excess. In addition, some of the municipalities decided to develop their own composting operations. While the Krehers (as well as some municipal officials) feel the Krehers' proposed tipping fee is less than what municipalities must spend to compost yard waste themselves, local politicians have come to view running a composting program as a positive public relations opportunity. In addition, municipalities are often able to borrow land, equipment, and personnel from other purposes so that costs are not always fully accounted. Farmers need to be aware of these challenges in municipal contracting. Where tipping fee income is important, they may want to get commitments from waste generators before making a major investment.

Moody Hill Farm

Moody Hill Farm is situated on more than 300 acres of hilly terrain in horse farm country. It pursues two primary activities: organic vegetable and compost production. A crew of four full-time and three part-time workers grow vegetables on 12 acres (on up to 40 acres in previous years) and in a 2700 square foot greenhouse. About three-fourths of the compost produced on the farm is used on-farm for vegetable production. Moody Hill Farms was one of the case study farms which participated in a detailed economic analysis (see Table 4).

Table 4. Moody Hill Farm.

Compost tasks and equipment usage for each task (1990)
Task Farm
labor
hours
Farm
labor
costs
Equipment usage
and comments
1. Planning, permitting, administration 1,000 $16,286 Computer used
2. Secretarial, bookkeeping, dispatching 2,340 $20,000 Computer used
3. Off-site collection/trucking of materials
100% of truck and container use
5,840 $58,400 Trucks and containers used
4. Materials receiving on-site
12% of front loader use
948 $11,409 Unload containers, stack material,
maintain pile with front loader
5. Day to day management 832 $14,086 No major equipment used
6. Preprocessing of material
2% of front loader use
688 $6,409 Sort for trash, preblend piles with front loader
7. Pile formation and mixing materials
33% of front loader use
29% of bulldozer use
7% of skid loader use
1,292 $13,867 Front loader forms windrow, skid
loader maintains pile edges, bull-
dozer shapes and maintains passive piles
8. Pile turning
4% of front loader use
21% of skid loader use
100% of windrow turner use
1,552 $16,467 Piles turned and shaped with
windrow turner, secondarily with
front loader and skid loader
9. Site and machine maintenance
10% of front loader use
28% of bulldozer use (turning area)
43% of bulldozer use (other areas)
21% of skid loader use
1,850 $22,122 Bulldozer, skid and front loaders
used to maintain site surface,
ditches
10. Shredding, screening of products
21% of skid loader use
100% of shredder/screener use
100% of power screen use
100% of large loader use
1,002 $9,345 Shredder and screener used with
loader
11. Market, blend, load, ship, bag producta
39% of front loader use
30% of skid loader use
100% of soil bagger use
850 $11,557 Bagger, trucks, skid, and front loaders used
12. Miscellaneous 370 $5,643 No equipment
Total annual hours and wages b 18,564 $205,591
Note: Total hours are likely to be more trustworthy than hours allocated to each task.
aIncludes 120 hours for bagging labor at $1,200 labor cost.
bSum of on-site pile management tasks (4­9) was 7,162 hours at $84,360. Sum of market related tasks (10­11) was 1,852 hours at $20,902.

Compost equipment costs and total use
Equipment Actual
cost
Year
purchased
Vintage Annual
hours
Approx.
cost
per
hourb
Traditional earth moving
Front-end loader (Michigan L90)
Larger front-end loader (Michigan L-120
Bulldozer (John Deere 450)
Skid loader (Gehl 6625, 1 yard bucket)
$120,000
-c
$45,000
$22,000
1988
-
1987
1989
1987
-
1987
1989
980
800
630
570
$50
$55
$35
$10
Specialized for composting process
Windrow turner, self-propelled (Scarab 14)
$50,000 1987 1976 425 $45
Screening and bagging
Shredder/screener (Royer 300)
Screener (Powerscreen MK II)
Soil bagger (Bouldin and Lawson)
$42,000
$50,000
$150,000d
1988
1990
1988
1988
mid-1980s
-
270
650
60
-
-
-
Collectione
Collection truck 1
Collection truck 2
Collection truck 3
50 containers (30 cubic yard)
$90,000
$32,000
$25,000
$3,000
1988
1987
1989
-
1988
1978
-
-
-
-
-
-
-
-
-
On-farm compost use
Tractor (Belarus 70-horsepower)
Spin spreader (Stoltzfus 5-ton)
$14,000
$100g
1990
-
1990
-
-
-
-
-
bApproximate owning and operating costs excluding labor charges (estimated at $10 per hour).
cTemporary rental.
dApproximate.
eFleet mileage of about 3,900 miles per month.
fCost for each container. Rental fee of $125 per month charged to customer.
gRental cost per day.

Estimated quantity Revenue
Compostable materials (cubic yards) (bags) (per cubic
yards
(per bag)
On-farm
Grass
60 - - -
Off-farm
Municipal leaves
Wood chips/shavings as horse farm bedding
Dairy cow manures

350
25,000
5,000

-
-

$1.50
$5
-

-
-
-
Total (per year 30,410
Products
Compost
Bagged compost
Potting soil
Bagged potting soil
Topsoil (25% compost)

5,880h
120
240i
60
1,000

-
3,600
-
3,000
-

$18
$72
$52
$103.50
$18

-
$2.40
-
$2.07
-
Approximate total compost 6,500
Revenues per year
30-yard container rentals: $5,000; Tipping fees and sales: $195,695
"Market value" of compost used on farmj
Compost: $81,000; Potting soil: $1,560
Note: Assuming volume reduction of 50% on average, the roughly 6,000-7,000 yards of compost used would have been derived from 12,000-14,000 yards of incoming material. Roughly 16,000-18,000 yards of the material that arrives on the farm is, therefore, not actively composted. Instead, it is piled in very large piles for slow passive composting.

h4,500 cubic yards used on farm.
i30 cubic yards used on farm.
jVolume times sales price.

Other fixed costs of composting
Land value-part of farm land (heavy clay soils) purchased at approximately $8,000 per acre (6 acres for $48,000) for compost area
Initial site preparationg-rading, surfacing, drainage, and gate installation with rented bulldozer, excavator, and loader required approximately 800 hours of machine work in 1988. Rental cost was roughly $40,000.
Additional drainage work-new pond and ditches at $10,000 were cost-shared with ASCS.
Structures-trailer and large storage building. Cost not available.

Reprinted with permission from On-Farm Composting Handbook. Published by NRAES. (607) 255-7654.

The compost production activity occupies a staff of 6-8 depending on the state of the economy and associated level of demand for manure removal services. At full staffing one position is secretarial, two and a half are for site workers/equipment operators, and two and a half positions are devoted to off-site collection of manures. The president and vice president of the farm corporation combine administrative and marketing responsibilities with site work. Total payroll is about $200,000.

The composting activity occurs on 6 graded acres of converted cropland that include structures (the greenhouse, a trailer/office, a large aluminum storage building), composting, curing and run-off control areas. Large areas at the margins of the main composting pad are covered or "embanked" with slowly decomposing but otherwise unmanaged manure/bedding mixtures. The actively managed windrows are turned "as little as possible" - half a dozen to a dozen times in a three to five month period, primarily with a large self-propelled windrow turner capable of processing more than a thousand tons per hour.

Between 30,000 and 40,000 cubic yards of organic materials are accepted each year. Of these, approximately 12,000 to 14,000 are actively composted. The remaining material is embanked. In these totals are included small volumes of grass from the farm, dairy manures from other farms, and municipal leaves. However, well over 4/5 of the material is wood chips and shavings mixed with horse manure. A fleet of three trucks averages 3,900 miles a month collecting manures (and delivering a small amount of compost). The manure is picked up in 35-50 thirty cubic yard containers rented out to customers for a fee of $125 per month. A tipping fee is also charged as per formula related to distance and other factors, and averages out at about $5 per cubic yard. The average collection round trip is approximately 50 miles.

The compost operation uses a great deal of equipment in addition to the windrow turner and collection trucks. The farm owns a 156 hp front-end loader that is used for tasks throughout the process, including contaminant sorting and material blending on arrival, and building, sorting and neatening windrows. Sometimes the first turning of the windrowed manure is done with a loader - the optimal initial pile size is not easily managed by the windrow turner which is designed to straddle the windrow. A smaller skid loader is used to maintain the pile edges and the site, as well as in the screening, mixing and loading of final products. A bulldozer helps shape and maintain the site surface and embanked compost, the access road and drainage ditches.

Other equipment is used to upgrade the quality of the compost. In 1990 an additional very large front-end loader was rented for almost half a year for a number of tasks but especially to assist with compost screening. Also in order to produce increased quantities of high grade compost product, the farm rented a high capacity screener for much of 1990. The screener complements a soil shredder/screener of lesser capacity owned by the farm. Finally, the compost operation owns a soil bagger which bagged almost 7,000 bags of compost and potting soil in 1990.

In sum (not including the rented machinery) well over $250,000 has been invested on equipment primarily used for composting itself; an additional $200,000 is invested in screening and bagging equipment; and almost $300,000 has been invested in collection trucks and containers. Much of this equipment was purchased second hand, so new replacement values would be higher. Other fixed costs include the roughly $50,000 land value, an investment of another $50,000 or more in initial site preparation and holding ponds and run-off management system, plus the value of the structures. The compost related revenues derived from tipping fees and container rentals totaled more than $125,000. Additional revenues of slightly under $50,000 were earned from compost sales of bulk compost (at $18/cy), bagged compost ($2.40 per 40 lb bag or $72/cy), potting soil ($52/cy), and bagged potting soil ($2.07 per 22 quart bag or $103.50/cy). Customers for the compost included primarily area landscapers, nurseries, and residents. Other farmers and local government parks departments purchased smaller amounts. The potting soil was primarily purchased by other farmers, followed by the landscapers, nurseries, parks departments and lastly, local residents. Sixty percent of the topsoil was purchased by area landscapers, with the remainder split evenly between residents and parks departments.

Much of the collected manure and compost value was "invested" and waits to be fully realized: 4,530 yards of compost and potting soil have been used to improve farm fields or in the greenhouse. The compost was applied to fields at a light rate of about 5-10 tons per acre using a recently purchased soviet made tractor and rented spin spreader. Again as an organic farm, the many short and especially longer term benefits of adding organic compost to the soil command a premium. Finally, the residual 15,000 yards of manures in the embankments are passively being transformed into compost. While this slow and cheap approach to compost production has yet to prove itself, it will eventually lead to substantial additional compost inventory.

Oswego County

In 1990 Oswego County estimates that it chipped 4,000 tons of brush and tree limbs, and composted 700 tons of other organic materials. The county composts 1,200 cubic yards a year at its main site constructed at the county landfill. While the bulk of the material composted is leaves, animal manures (including elephant manures from a circus) and various vegetable products have been mixed in with the rest of the compostables. Frozen food wastes from Bird's Eye Foods and mildewed corn from the Port of Oswego have been incorporated. The materials are mixed and composted in windrows on a paved pad, generally in 2 or 3 piles. They are monitored with a temperature probe and turned every couple of weeks, except during winter, with a large payloader. Run-off is channeled into a sand filter. The finished compost is given away to anyone from the county after 10-12 months of processing. The primary economic incentive to the county to compost these wastes is the space saved in the landfill.

Rose Valley Farm

Rose Valley Farm is an organic vegetable producer that has composted a variety of materials using the static pile method. Approximately half of the 60 acre farm is devoted to pasture or small fruit and vegetable production. A wide variety of crops is grown, though the farm owner and his partner specialize in asparagus, garlic, greens and root crops. Rose Valley Farm is one of a growing number of small to medium sized diversified vegetable farms, and has cooperated in a detailed economic analysis to help characterize the costs of composting at that scale (see Table 5).

Table 5. Rose Valley Farm

Activities
Tasks Farm
Expenses
Farm
labor
time
(hours)
Farm
machine
time
(hours)
Comments
Site preparation
Land value
Planning, build access road, prepare site

$550
$0

-
8

-
5

Local land value estimated
Tractor/loader used
Materials collection and purchase $34 20 6 Used farm manure spreader
Preprocessing of materials (green chop) $0 2 2 Used tractor, chopper, wagon
Pile formation $45 24 24 Used spreader, tractor, loader
Maintain, monitor (site repair, cover piles, and so on $0 8 1 Area disced to smooth ruts
Field spreading $0 30 30 Used modified spreader

Materials
Compostable material Estimated
quantity
Farm labor
time for
delivery
hours
Cash cost
On-farm

Green chop (timothy, alfalfa)

6 cubic yards 2 0
Off-farm
Wet hay
Wood chips
Chicken manure
Well-rotted horse manure
Race-track horse manures
Sheep manure, straw bedding
Lake weed
Waste vegetables (for example, squash)
9 dry tons (dry)
2 tons
30 tons
45 tons
10 tons
80 tons
720 tons
Less than 1 ton
0
0
0
6
0
12
0
0
$9
$0
$25
$0
$0
$0
$0
$0
Note: Total for 1990 materials was about 900 tons. However, an undetermined amount of some of these materials are in stockpiles not mixed into the windrow.

Farm compost equipment
Equipment Model and
features
Cost Year
purchased
Estimated
hourly
cost
Manure spreader 8-ton New Idea $75a 1980s $10b
Manure spreader 516 New Holland 5-ton series -c - -
Dump bed 8-ton $3,000 1991 $15b
Tractor Belarus, 60-horsepower $9,000 1986 $25b
Loader Allied $3,100d 1989 $6b
Tractor 50-horsepower JD 2010 $7,500 1987 $25b
Flail JD 520 $7,500e 1982 $15
Self-unloading forage wagon PAPEC $9,000e 1970 $12
Modified spreader John Deere #33 100-bushel $100f - $5
Disc 10-foot transport KBA-JD $7,000e - $15
Temperature probe $75e - -
aPlus trade and repairs.
bVery rough hourly owning and operating cost estimates are based on cost and use data in Dhillon and Palladino and in Snyder. They include $6.50 per hour operator labor cost.
cBorrowed from sheep farm for delivery and spreading.
dIncluding manure tines.
e1991 replacement value. Actual purchase price unknown.
fCurrent market value. Actual purchase price unknown.

Reprinted with permission from On-Farm Composting Handbook. Published by NRAES. (607) 255-7654.

This farm, like many other organic farms, depends more heavily than conventional farms on labor and is less dependent on synthetic chemical fertilizers and pesticides or expensive equipment. Most organic farms routinely apply manures, which obviously have their own costs of collection and spreading, directly in order to build the soils and add fertilizer value. Any farmer considering composting should note that composting leads to some nitrogen volatilization (i.e. loss) before use on plants (as does manure storage; Witter and Lopez-Real, 1987). Despite this loss, compost can have several desirable properties of special interest to organic farmers, such as weed and disease suppression without use of synthetic chemicals. Moreover, it stabilizes the remaining compost components and may improve long-term nutrient availability (Brinton 1985).

The compost operation occupies about a one acre site on a corner of the farm. The nearest neighbors are thousands of feet removed. The site is very near a locally maintained paved road, but a short roadbed of crushed limestone had to be built into the site to allow delivery truck access. Approximately four hours of farm labor to grade the access road was required. In a deal to compost certain county wastes, free limestone was delivered by the county government. The site has an estimated land value of $500-600. The farm as a whole is in a state agricultural district, and the site is part of a small parcel currently enrolled in a USDA conservation easement program. Hence, the land is utilized at no cost attributable to composting (an effective opportunity cost of zero).

The prospect of composting lake weed from the county harvesting program was the major stimulus to begin composting on Rose Valley Farm. However, a variety of materials generated on and off-farm are composted (see Table 5), reflecting the farm's interest in taking advantage of opportunities to add to its soils materials rich in both nutrients and organic matter. Lake weed, which has a 90% water content and low nutrient concentrations, constitutes the bulk of the material composted though its volume reduces dramatically and quickly. No tipping fees were received for any of the materials brought onto the farm; $25 was paid by the farm for delivery of a single 30 ton load of nutrient rich liquid chicken manure, a nominal $.03 per bale was paid for a neighbor's damaged (wet) hay.

The lake weed, like most of the other composted materials, is delivered to the site by the generator of the material. Only a couple of hours annually of farm labor were required during the year to meet the delivery trucks. Other collection/delivery costs to the farm were associated with the sheep and horse manures collected from two neighbors. About 18 hours of farm labor in 1990 were required to collect and move 125 tons of manure the mile or so to the farm. While the farm provided its own manure spreader for collection of the horse manure, it borrowed the other neighbor's spreader for delivery of the sheep manure. In addition, the green chop (timothy, alfalfa) added to the compost piles required a couple of hours in order to run the flail chopper and transport the material the short distance to the compost site.

The main compost task for static pile composting is formation of the compost piles. On this farm, formation of a 90 foot length of windrowed material required three or four half-day sessions in the months of July and September, adding up to about 24 person-hours of labor. This included time to lay down a length of perforated black pipe covered by wood chips at the bottom of the pile. This static pile modification, of undocumented effect, is intended to improve the natural circulation of air through the pile without the expense of a blower and controls associated with an aerated static pile. The tractor with loader was used to fill the manure spreader. As it backs over the length of pipe discharging and mixing material, the spreader forms the piles to the height of its bed. A couple of hours in total were required to first grease and eventually clean this machinery when used for composting, plus about another hour or so to install manure tines on the loader. After forming the piles, an additional hour was required to disc the site in order to remove the ruts caused by equipment movement over the unsurfaced site.

Once formed, the piles were not disturbed. However, they were kept covered with plastic anchored by old tires to keep off additional moisture. This required about four hours of labor during the year. Samples were taken for lab analysis, and temperatures were monitored with a probe daily the first week and then less often, perhaps requiring an extra hour or two of work during the year.

After letting each pile compost undisturbed for a full year, all of the compost product is used on the farm. Very small amounts of compost have been used to make a potting soil acceptable under organic growing standards. This potting soil displaced a commercial mix, and was used to start various plants and orchard trees, including 15,000 broccoli plants. The vast bulk of the finished compost has been land applied at a rate of 1.25-1.5 cubic yards per quarter acre of crop land. For the sake of convenience of application, rock phosphate was applied with the compost and use of supplemental magnesium is planned for the future. Field spreading of the annual production of roughly 250 tons of finished compost required about 3-4 days of labor with an old slightly modified 100 bushel manure spreader.

In sum, the activity from materials collection to final compost use required about 2 weeks of labor for the year, not counting the initial site preparation time (see Table 5). Of this, less than four days of time were devoted to the compost production tasks themselves, the remainder being devoted to collection of materials and final spreading of the compost. Out of pocket costs were kept below $150, not including several hundred dollars for lab testing. No specialized equipment (other than a temperature probe) was involved in the compost operation, and the total expenditures on farm equipment involved in various parts of the composting cycle was under $25,000. (Almost all equipment was used when purchased; replacement of all the equipment used during the compost cycle with new equipment would cost approximately $75,000 - Snyder 1991). The equipment ownership and operating costs attributable to the composting operation are under $1,500. Thus, even assigning a reasonable wage rate of $6.50 per hour, the roughly estimated costs of making and applying the compost are certainly less than $5 per ton of incoming material, and almost 2/3 of that cost is devoted to collection and field spreading. Other experimental studies of the economics of municipal or agricultural composting report generally consistent or somewhat higher costs.

Note finally that the compost earned no off-farm revenues and consisted almost entirely of materials that were brought onto the farm specifically to be composted. The economic value of the compost on this and most other vegetable farms is primarily due to its role in increasing soil productivity as a fertilizer, soil amendment and side dressing. All else equal, composting will reduce the volume of manure to be spread. However, since wet manures and similar materials are normally composted with added bulking materials, a significant amount of additional compost mass can be produced. While requiring more time to process and spread than direct manure spreading, the increased amount of stabilized compost is perceived as a benefit on farms like the one in question. However, for "practical reasons" (Dhillon and Palladino, 1981) including time, space and labor constraints, the use of compost on most organic farms has been less extensive than of uncomposted manures.

Seneca Foods

Seneca Foods is a major food processor in the Ontario and Finger Lakes region of Western New York. They have been considering composting for several years as a means to dispose of their processing residues. At this project's inception they were considering developing their own composting operation. However, a more detailed analysis of their waste stream characteristics and alternative disposal costs indicated that composting would offer limited advantages at present. Most of Seneca Foods' vegetative wastes are directly applied to agricultural land, often returned to the farmers who supply their produce. They have two major waste materials for which this alternative is inadequate: grape pomace and apple pomace. Composting of these materials has been considered, but the seasonality of production and the costs of developing a suitable facility are significant barriers. Seneca Foods did provide a range of materials for analysis and inclusion in our data base, and their grape pomace was successfully composted in the experimental composting trials described below.

Agricultural Composting: Process Optimization

Raw Material Data Base

There is a lack of fundamental information on the characteristics of materials which are commonly composted. To formulate a suitable mixture of materials for any composting process, the properties of each material need to be known so that a proper "recipe" can be constructed. A farmer should have information on typical physical and chemical characteristics such as material density, nutrient composition, carbon:nitrogen ratio, pH, moisture content, carbohydrate composition, porosity, electrical conductivity and particle size distribution. Raw materials were collected and analyzed for several chemical and physical properties which are of interest in a composting process.

Raw materials included those which are of interest to farm composting operations including animal manures, crop residues, food processing wastes, yard waste, bulking agents and papers. Each material was obtained and tested in as pure a form as possible. In addition, several mixes of common agricultural materials, such as dairy manure with bedding, were tested since it would be unusual for a farmer to have only pure dairy manure, without bedding, available for composting.

Laboratories at Cornell were used to test 24 materials and for 15 chemical and physical characteristics. Table 6 lists this data base of material characteristics. Other researcher's findings on compost characteristics are listed in Appendix D.

Table 6. Compostable Raw Materials

Agricultural Mixtures Study

The objective of this part of the study was to monitor the progress of agricultural and food processing wastes as they decomposed through the composting process. Composting mixtures were varied to exhibit a range of CARBON:NITROGEN (C:N) ratios or the carbon:nitrogen ratio was held fixed and the types of materials used to create this mix were varied. The experiments were carried out in twelve plastic bins, each holding approximately one cubic meter of material. 350 5/8 inch diameter holes were drilled in the bottom of each bin to promote passive aeration, and loose fitting plywood lids were constructed to protect the mixtures from precipitation. Bins were filled with 18 different waste mixtures after blending in an adapted 9 cubic yard cement mixer. Each bin was monitored over 25 to 35 days, depending on the mixture. Temperature was monitored daily at three pile depths. Ambient temperature was recorded at time of monitoring. Compost moisture content was analyzed every few days. Fat, nitrogen, and carbohydrate levels were only analyzed every week for a few of the mixtures due to the cost and complexity of these analyses.

Round One tested nine animal manure mixtures and obtained good results for temperature and moisture trends. Tested materials included poultry manure mixed with shavings, or with shavings and peat moss. Dairy manure was mixed with shavings only. Round Two tested five mixtures of dead chickens mixed with shavings and/or peat moss, three mixtures of food waste with wood chips, and one bin with aquatic weeds. While temperature and moisture proved relatively easy to monitor, the chemical analysis parameters showed a high degree of variability. It would appear that the major challenge to obtaining good data in these experiments was in gathering samples for analysis. In general, three grab samples were taken from a limited area 20 to 30 cm down from the surface of the pile, after which the bin was crudely mixed with an aeration device. This relatively small number of samples and the lack of composting from a larger area led to high degrees of variability. Even in a well mixed and properly managed compost pile, there can be significant variability in pile composition due to the very heterogeneous nature of the raw materials involved.

Perhaps the most significant finding of the mixture study was the ability to stretch the C:N ratio of agricultural mixtures beyond the usually recommended 30:1 to 50-60:1. Agricultural mixtures exhibited high temperatures and decomposition continued even with the higher C:N ratios. Where adequate carbon sources are available, this provides an opportunity to minimize nitrogen loss and water quality concerns (Rymshaw et al., 1992).

Typical trends in compost processes were verified in each of the composting mixtures. After an initial heating phase, pile temperature trended downward over the composting time period of about 35 days. Pile temperature stabilized with ambient temperature when the composting process was complete or when moisture became limiting (which occurred in several of the drier mixtures). It only took about one day for the piles to reach maximum operating temperatures for composting after being place in the bins. There was about a one day lag period between significant changes in ambient temperature trend versus compost pile temperature trends. The compost pile temperature followed trends in the ambient temperature even within the middle of the pile. The temperature near the top of the pile was consistently a few degrees higher than near the middle of the pile.

Recommendations for Agricultural Composting

Agricultural composting continues to hold considerable promise as a waste management strategy. However, the environmental and possible economic benefits of composting are challenged by a variety of constraints. Several of the most important of these constraints are listed and discussed below.

  1. Inconsistent availability of clean sources of low moisture, high carbon amendments
  2. Regulatory constraints on paper and cardboard.
  3. High equipment cost and significant economies of scale.
  4. Tipping fee competition from market-subsidized competitors.
  5. Lack of strong compost market and market competition from other compost products.
  6. Lack of recognition of compost attributes such as biological control capabilities and soil fertility effects.

The first two constraints are closely related. Both are important because many of the waste materials considered for composting are high in moisture and nitrogen. Leaf composting is relatively easy on its own, but generators of manure, sewage sludge, grass clippings or aquatic weeds all require dry high carbon amendments. While finished compost can itself serve as such an amendment, using compost reduces the quantity available for utilization or sale. Some of the promising amendments include leaves, well bedded horse manure, wood chips or sawdust from lumber mills, and paper and cardboard materials. The availability of these materials varies widely in different parts of the state. For a farmer trying to improve manure management, the additional costs of composting often need to be offset by tipping fee income. In the Hudson Valley and some other locations a tipping fee can be charged for horse manure, especially if collection service is included as demonstrated by Moody Hill Farms. Wood chips and sawdust are frequently marketed as bedding materials, and are unlikely to pay for disposal. Leaves are a definite possibility, although the Kreher experience illustrates that competition for this material from nurseries and municipal programs may keep tipping fees artificially low.

Perhaps the most widely available high carbon amendment is waste paper/cardboard. As Gerster Farms demonstrate, this material can prove an effective amendment for manures and other high nitrogen wastes. With secondary paper, markets saturated by a glut of recovered material, paper and cardboard can generate a significant tipping fee (although this may drop as new paper recycling capacity is built). However, they do require special processing for size reduction, and present NYSDEC regulations treat these materials as solid waste. While farmers are exempted from permitting if they use waste paper as bedding before composting, the quantities needed for composting greatly exceed normal dairy bedding needs. The solid waste composting regulations require extensive engineering design, pathogen monitoring, and compost product analysis that were designed for sludge and mixed solid waste, rather than a clean separated paper stream. Complying with these regulations is a considerable impediment to the use of waste paper/cardboard in agricultural composting operations.

Agricultural composting is subject to significant economies of scale, and even a medium to large operation (15,000 cubic yards/year) would underutilize most specialized composting equipment (see Tables 1 and 2). This specialized equipment is expensive, and it is difficult to justify such a purchase for most individual farms. Because compost only needs turning on an occasional basis, a specialized windrow turner could readily service several farms. An infrastructure which allowed such cooperative use could reduce the costs of agricultural composting and encourage farmer interest. There are a variety of ways to set up such an infrastructure. A local association could purchase a machine and make it available to farmers, as was previously done with agricultural drainage equipment by the Soil and Water Conservation Districts in New York State. Private companies could also provide a " custom composting" service, as is commonly done with combining, fertilization, and pesticide application today. However, as the Amar case study suggests, a successful privatized service requires a greater concentration of agricultural composting activity than presently exists in New York State.

Farmers who depend on tipping fees to cover their composting costs may face considerable competition from other private enterprises as well as local governments. While farmers have many of the prerequisites for composting, including land, some of the needed equipment, and familiarity with biological waste management, farmers also need to pay close attention to the bottom line. As the Krehers case study indicates, other entities may not have the same constraints. Local governments can choose to subsidize a politically popular yard waste composting program, making it difficult for farmers to compete. And compost producers who have a high value use for the compost, such as nurseries and greenhouses, can use that market value to reduce their tipping fees.

Compost product marketing can also suffer from a variety of hidden subsidies, all of which make it difficult for farmers to compete. Local governments often give away compost as a public relations gesture, driving down the price. And even private operations which are diverting materials from an expensive landfill can subsidize the costs of compost marketing with the avoided disposal costs. While this may prove an advantage for food processors such as Anheuser-Busch, it will reduce the market value of compost for other private producers.

Compost markets are presently split between the high value nursery and greenhouse markets and low value agricultural, topsoil and reclamation uses. While increased substitution of compost for peat can continue to make inroads into the high value markets, these markets are relatively small. New applications and increased utilization by the agricultural sector will be critical to market expansion. Promising research in the use of compost for biological pest control and soil fertility management will be important for the ultimate expansion of agricultural use.

There are a number of steps which governmental agencies can take to encourage agricultural composting. These recommendations help address the constraints identified above, and build a base for increased adoption of composting as an agricultural waste management strategy.

  1. Minimize regulatory constraints on farm-composted materials. Regulatory relief could take two forms. First, a streamlining of the permitting process should be seriously considered. NYSDEC solid waste permits require an investment of time and money that most farmers cannot afford. While a generic permit application form is available for farmers interested in yard wastes (see Appendix B), a complementary approach might be to require adherence to "group permit requirements" for agricultural composting operations of less than a certain size. The DEC could still maintain regulatory oversight for violations and nuisance complaints. A second approach would be to increase the volume and types of material that farms can handle without permits. For example, increasing the volume exemption for yard waste from 3,000 to 10,000 cubic yards would allow a 200 cow dairy to use this amendment without needing a permit. Adding waste paper and cardboard to the list of minimally regulated materials would provide considerable relief to livestock manure composters.
  2. Encourage local zoning to allow compost facilities as a normal agricultural operation. Manure management has always been a part of agriculture, and composting should be subject to the same protection as land application. While some limitations may be needed to differentiate agricultural waste management from industrial or commercial activity, composting should not be penalized.
  3. Provide government assistance for composting equipment and site preparation. This could include approaches such as cost sharing through the ASCS, cooperative purchasing by groups of farm composters, perhaps through the SWCD, or equipment sharing with municipal composting facilities. Agricultural agencies should recognize investments in composting as equivalent to manure storages or lagoons. A targeted demonstration pilot program with a group of cooperating farmers could provide an example to others around the state,
  4. Develop procurement guidelines for state agencies to utilize compost in preference to peat and topsoil. The state can set an important example in encouraging compost utilization. New York State agencies which should be involved include: Office of General Services, Department of Transportation, Office of Standards and Purchase, and the Thruway Authority.
  5. Support research and demonstration programs which explore new applications for compost, particularly in the agricultural sector. Biological control of soil born diseases, soil fertility management, groundwater protection, and erosion control are all positive prospects for increased compost use. These benefits need to be understood and documented for agricultural use.
Agricultural composting shows considerable promise as a waste management strategy for the future. Benefits such as improved nutrient management, enhanced water quality, and reduced nuisance odors can all be achieved. But as this study documents, composting also carries additional costs and these must be carefully considered. Since many of the benefits accrue off the individual farm, it makes sense for society to share more broadly in the costs. These recommendations provide a modest framework to begin to build an agricultural composting infrastructure for New York State.

References

Allen, David H., (Farmer Automatic of America, Inc. ) 1991. Personal communication.

Bartlett, Andrew. 1987. "Windrow Composting of Poultry and Horse Manure with Hay", in Proceedings: On-Farm Composting Conference, January 15, 1987, Cooperative Extension, University of Massachusetts, pp. 19-24.

Beers, A.R., and T. J. Getz. "Composting Biosolids saves $3.3 million in landfill costs. BioCycle 33(5):42,76-77.

Brinton, W. F. Jr. 1985. "Nitrogen Response of Maize to Fresh and Composted Manure", Biological Agriculture and Horticulture. Vol 3, pp. 55-64

Brinton, W. F. Jr. and Milton D. Seekins. 1988. "Composting Fish By-Products: A Feasibility Study". Time and Tide RC&D, Mid Coast Compost Consortium.

Caterpillar, Inc. 1989. Caterpillar Performance Handbook. Caterpillar Inc., Peoria Illinois.

Colacicco, Daniel. 1982. "Economic Aspects of Composting". BioCycle, Vol. 23, pp. 26-29.

Dhillon, Pritam S. and Barbara A. Palladino. 1981. Characteristics of Organic Vegetable Farms in New Jersey with Estimated Costs and Returns for Selected Organic Crops. A.E. 381, New Jersey Agricultural Experiment Station, Rutgers University.

Dreyfus, Daniel. 1990. Feasibility of On-Farm Composting. RRC/RU-90/2, Rural Urban Office, Rodale Institute.

Fulford, Bruce. 1987. "Composting Dairy Manure with Newspaper and Cardboard", in Proceedings: On-Farm Composting Conference, January 15, 1987, Cooperative Extension, University of Massachusetts, pp. 13-18.

Fuller, E., and M. F. McGuire. 1988. Minnesota Farm Machinery Economic Cost Estimates for 1988. AG-FO-2308. Minnesota Extension Service, University of Minnesota.

Glaum, Marvin (Glaum Egg Ranch) 1991. Personal communication.

Gresham, Cyane W., Rhonda R. Janke, and Jeffery Moyer. 1990. Composting of Poultry Litter, Leaves and Newspaper. RRC/RU-90/1, Rural Urban Office, Rodale Institute.

Kuter, Geoffrey. 1987. "Commercial In-Vessel Composting of Agricultural Wastes", in Proceedings: On-Farm Composting Conference, January 15, 1987, Cooperative Extension, University of Massachusetts, pp. 7-11.

Milligan, Robert A., Linda D. Putnam, Carl Crispell, Gerald A. LeClar, and A. Edward Staehr. 1991. Dairy Farm Business Summary, A.E. Ext. 91-10, Department of Agricultural Economics, Cornell University.

Richard, Tom. 1991. Personal communication.

Richard, Thomas L., Nancy M. Dickson and Sally J. Rowland. 1990. Yard Waste Management: A Planning Guide for New York State. NYSDEC. Albany, NY.

Romeiser, Brian. 1991. Manchester- Shortsville Sewage Treatment Facility, personal communication.

Rymshaw, E., M.F. Walter, and T.L. Richard. 1992. Agricultural Composting: Environmental Monitoring and Management. Final Report. Department of Agricultural and Biological Engineering, Cornell University, Ithaca, NY.

Rynk, Robert. "Composting as a Dairy Manure Management Technique", Dairy Manure Management: Proceedings from the Dairy Manure Management Symposium, February 22- 24, 1989. NRAES-31, Northeast Regional Agricultural Engineering Service, Cooperative Extension, Cornell University.

Simpson, Michael. 1987. "Economics of Agricultural Composting", in Proceedings: On- Farm Composting Conference, January 15, 1987, Cooperative Extension, University of Massachusetts, pp. 55-68.

Tarnoff, M. and R. Koelsch. 1981. Fuel Requirement of Field Operations. FS-28, Northeast Regional Agricultural Engineering Service, Cooperative Extension, Cornell University.

Tennant, Gary. 1991. Cornell University Farm Services, personal communication.

Snyder, Darwin P. 1984. Overhead Costs from Farm Cost Accounts (Final Report). A.E. Res. 84-17, Department of Agricultural Economics, Cornell University.

Snyder, Darwin P. 1990. Field Crop Enterprise Budget Update: 1990 Cost and Return Projections and Grower Worksheets, New York State. A.E. Res. 90-7, Department of Agricultural Economics, Cornell University.

Snyder, Darwin P. 1991. 1991 Budget Guide: Estimated Prices for Crop Operating Inputs and Capital Investment Items. A.E. Res. 91-2, Department of Agricultural Economics, Cornell University.

Walker, John M., Nora Goldstein and Ben Chan. 1989. "Evaluating the In-Vessel Composting Option", The BioCycle Guide to Composting Municipal Wastes, Emmaus, PA. pp. 58-68.

Witter, E. and J. M. Lopez-Real. 1987. "The Potential of Sewage Sludge and Composting in a Nitrogen Recycling Strategy for Agriculture", Biological Agriculture and Horticulture. Vol 5, pp. 1--23.

Publications with additional information on farm materials composting and composting principles:

Composting Fish By-Products: A Feasibility Study, 1988. Time & Tide RC&D, Mid-Coast Compost Consortium.

On-Farm Composting Conference, Proceedings, 1987. Cooperative Extension, University of Massachusetts, SP-154.

Update: Usable Waste Products for the Farm, 1990. Maine Department of Agriculture, Food and Rural Resources.

Usable Waste Products for the Farm, 1986. Maine Department of Agriculture, Food and Rural Resources.

Yard Waste Management- A Planning Guide for New York State, 1990. T.L. Richard, N. M. Dickson, S. J. Rowland. NYS Energy Research & Development Authority, Cornell Cooperative Extension, NYS Department of Environmental Conservation.

Feasibility of On-Farm Composting, 1990. Danial Dreyfus, Rodale Research Center, Rodale Institute

On-Farm Composting Manual, R. Rynk (ed.). NRAES, Ithaca, NY. Price: $15. 186 pp.


Appendices

APPENDIX A. Generic Permit Application

APPENDIX B. Data on Material Composition



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This page was created on March 14, 1996
This page was last updated on May 5, 1998