When properly managed, manure nutrients can be a valuable resource for the farm; however, failure to manage these nutrients wisely may hurt farm income, land, water, and air resources. Presented here is an overview of the market and non-market costs and benefits that producers should address before investing in a manure-handling system. Estimates of the market costs and benefits are provided for representative operations.
Often, manure storage is necessary to efficiently utilize available nutrients for growing crops and to minimize adverse environmental impacts. Yet, storage is only one component of a manure-handling system. Considered here are the costs of owning and operating a manure-handling system. A manure-handling system is defined as the structures, equipment and labor required to handle and/or store manure for an extended period of time (Table 20).
The benefits of a manure-handling system are realized when manure nutrients are used as a replacement for commercial fertilizers. Manure, depending upon the animal, contains 70 to 80% of the nitrogen, 60 to 85% of the phosphorus, and 80 to 90% of the potassium fed (Klausner, 1989). Recycling these nutrients through growing crops can benefit the farm operation and the environment.
Properly managed feedlots, manure stacks, and manure spreading can minimize run-off and the magnitude of other off-site impacts. Nutrient rich waters promote excessive algae and aquatic plant growth which can reduce wildlife habitat, recreational activities, and can increase downstream water-treatment costs. In addition, bacteria and other pathogens may enter surface waters with run-off, causing health concerns for end users. The cost for water treatment alone can be staggering. For example, a water filtration plant capable of minimizing the potential contamination of Giardia cysts and viruses in the source waters for New York City was estimated to cost between $3 and $8 billion to build and an additional $300 million to operate each year (Platt, 2000).
Over application of manure nutrients is costly for animal producers. Excess nutrients beyond the crops’ need provides no additional yield response, and increases the risk these nutrients will move off-site (Chapter 3, OSU Agronomy Guide, Tri-State Fertility Guide). Manure nutrients should be applied where they can be fully utilized by growing crops, increasing yields and reducing potential risks to the environment. The value of manure, as a nutrient resource, is only realized when manure is substituted for fertilizer. To do so, can increase farm profit.
Manure handling systems are unique to each operation and the individual management style. There are many factors to consider before selecting a system. Is there enough equipment and labor available to operate the system at critical times of the year? How well does the system control odors (Chapter 8, Odor and Dust Emission Control)? Can this operation best handle manure in liquid or solid form (Chapter 3, Manure-Management Systems)? What is the initial capital requirement? How will changes to the current manure-handling practice impact the demand for labor and equipment, and ultimately farm profits?
Four general characteristics define a manure-handling system. These are structural, equipment, nutrient, and labor (Table 20). Three of these characteristics—structural, equipment, and labor—define the costs of owning and operating the system. Nutrient characteristics define the benefit of manure when utilized as a substitute for purchased fertilizer.
| Table 20. Characteristics of a Manure-Handling System. | |
| Characteristic | Attribute |
|---|---|
| Structural |
|
| Equipment |
|
| Labor |
|
| Nutrient |
|
| Other considerations |
|
Each system begins by sizing the manure storage structure (Chapter 3). Not only do the number and type of animals determine the volume requirements, but also the total desired or needed storage period, the inclusion or exclusion of feedlot run-off, milking center wastewater, silage leachate, rainfall, availability of land, as well as other factors.
Your local Natural Resource Conservation Service can provide guidelines to accurately size a manure storage structure to meet current needs as well as planning for the future. In some cases, push-off ramps, reception pits, liners, and other secondary structures must be built to make the system operational. These additional structures add to the initial cost of the manure storage structure and impact the total cost of owning and operating the system.
The storage structure is only one aspect of the manure-handling and storage system. Each system requires equipment to move manure into and out of the holding structure. It is necessary to include the cost of owning and operating this equipment as a cost of the manure-handling system. Ownership and operating costs for the equipment include depreciation, interest, insurance, housing, and taxes as well as maintenance, repair, fuel, oil, and labor. The sum of these costs, on an annual basis, is the annual cost of owning and operating the manure-handling system.
Each system requires equipment to transport manure from the storage structure to the field for application and nutrient utilization. Some systems require a substantial investment in specialized equipment while others may more fully utilize existing equipment. An important question to ask—Is there sufficient equipment available to handle manure in a timely manner? For example, to move 1.4 million gallons of manure from a holding pond with a 3,000-gallon tanker will require more than 450 loads. Can your operation meet this kind of demand on labor and equipment when demand on labor and equipment is already high? For example, manure hauling prior to planting and/or during harvest to fully utilize available nutrients.
Alternatively, custom applicators specializing in manure application are available for hire. However, several important questions must be addressed. First, can a quality applicator be hired when the farm needs to apply manure nutrients? Will manure nutrients be applied when and where they are needed and in an environmentally responsible manner? Is it cost effective?
Labor requirements must be understood prior to investing in a system. Storing manure for extended periods can provide many advantages, but it also presents many challenges. For many operations, manure is frequently collected, and transferred into storage. This routine continues for months until the storage structure becomes full, at which point, dedication of labor and equipment is required to empty the holding structure.
Expanding upon the previous example, hauling two loads of manure per hour will require over 230 hours per year to haul 1.4 million gallons of manure. That is more than four weeks of continuous hauling each year. Furthermore, these labor requirements may coincide with spring planting, summer forage production, fall harvest, and fit within a narrow window of suitable soil moisture. Can your operation function under these constraints? Will additional labor be required and if so, is it available?
Contained within the manure holding structure is a “reserve” of nutrients that can reduce the need for purchased fertilizer. A laboratory analysis may be used to determine the nutrient content of manure in the holding structure. Local Extension offices have guidelines for collecting and shipping manure samples for nutrient analysis. Alternatively, guidelines for average manure nutrients can be obtained from this publication (Chapter 1, Manure Characteristics). Using this information, the total quantity and value of each nutrient can be determined for the volume of manure produced.
To maximize the value of manure, it should be applied at rates that meet the nutrient requirements of growing crops, assuming other factors such as a limiting nutrient, slope, leaching, and run-off potential are not more restrictive (Chapter 6, Land Application of Manure). Generally, the limiting nutrient is phosphorus, but it may be nitrogen or potassium in some situations. Nutrient utilization plans should be developed and followed to maximize the benefits of manure and minimize the potential for environmental damage.
Manure, especially odors associated with manure, readily move off-site, and in some situations become a nuisance to those downwind. These impacts are real and can negatively impact the farm’s long-term viability. This impact can be measured as a change in perceptions of how well the farm is managed (goodwill), quantified as legal fees accumulate defending civil action suits, or as a change in the value of neighboring properties. Regardless, the producers may pay awards from a civil action suit and incur the costs associated with implementing odor-reduction technology. Odor-reduction technology can be costly, depending upon the extent of odor control desired. Generally, it becomes more costly to remove increasingly more and more odor. An overview of odor control technologies is provided in Chapter 8, Odor and Dust Emission Control.
Hauling distance is influenced by factors such as land availability, crop rotation and nutrient need, current soil nutrient levels, slope, and the potential for manure entering water resources. In addition, distance from neighbors and public-use facilities should be considered. These factors should be assessed to determine which fields are used for manure application, which will determine the distance manure is hauled.
Hauling distance may be a significant factor influencing the manure-handling system decision. As animal density per acre of land increases, manure must be moved greater distances if soil nutrient levels are to remain in balance. Generally, liquid manure can be handled efficiently when moved relatively short distances. However, solid manure has a higher nutrient density and can be hauled greater distances more economically than dilute liquids.
Outlined here is a daily hauling system that handles manure as a semi-solid. This system is followed by three alternative manure-handing systems, which differ by the volume of manure and wastewater stored and the method used for manure application. Two of the liquid systems use an earthen holding pond to store animal manure and all wastewater sources. These two systems differ primarily by the total capacity of the storage structure desired. The fourth system handles manure as a semi-solid and diverts wastewater from other sources into a settling basin with a vegetative filter area for treatment. This analysis includes the cost of the secondary structures needed to make each system work and is sized for 100 lactating dairy cows weighing 1,400 lb each, on average.
Often, a daily haul system will have little or no manure storage capacity beyond what accumulates in the barn and/or in the spreader. Handling manure from this type of confinement system requires a tractor, box spreader, and loader. Manure is scraped directly into the box spreader and transported to the field for spreading daily or very frequently. The total cost of owning and operating this type of system for 100 lactating dairy cows is about $18,000 per year (Table 21) which includes a vegetative filter area to treat feedlot run-off, silage leachate, and milking center wastewater (Chapter 5, Farmstead Runoff Control).
| Table 21. Estimated Cost for Two Daily Haul Systems. | ||
| Daily Haul (365 day) | Daily Haul (180 days) | |
|---|---|---|
| Tons of manure hauled | 2,700 | 1,350 |
| Total cost | $18,000 | $15,800 |
| Nutrient value | $12,100 | $12,100 |
| Net cost | $5,900 | $3,700 |
| Cost per cow per year | $59 | $37 |
One hundred lactating dairy cows generate about 2,700 tons of manure (including bedding) each year. The nutrient value of this manure is estimated to be about $12,100 when valued at commercial fertilizer rates. In 2001 Ohio farmers paid $0.29/lb of nitrogen, $0.25/lb of phosphorus, and $0.14/lb of potassium (Ohio Department of Agriculture, 2001). The net cost (cost of owning and operating equipment plus the cost of owning and operating settling basin less the value of the manure nutrients) for this type of manure handling is expected to be about $6,000 per year ($59 per cow per year).
Often dairy operations of this size will keep cows on pasture for six months of the year. This practice reduces the annual cost of manure handling. For these operations, about 1,350 tons of manure would be hauled during periods when animals are confined (six months). During the time animals are on pasture, it is assumed that all manure generated during this period is distributed on the pasture, and the nutrients are utilized by the growing crop. Any supplemental fertilization of the pasture accounts for the addition of the manure nutrients. This system is expected to have an annual cost of owning and operating of about $3,700 per year ($37 per cow per year).
Alternatively, animal manure can be stored for an extended period of time and applied when growing crops can more fully utilize available nutrients. Three systems are presented that utilize varying manure storage strategies (Table 22).
| Table 22. Manure Handling and Storage System Overview. | |||
| 365-Day Liquid-Manure System (1,400,000 gal) | 180-Day Liquid-Manure System (700,000 gal) | 90-Day Solid-Manure System (675 ton) | 365-Day Daily Haul (2,700 ton) |
|---|---|---|---|
Designed for:
|
Designed for:
|
Designed for:
|
No storage beyond barn accumulation and spreader capacity. Settling basin + filter area:
|
Two liquid manure-handling systems store all sources of manure and wastewater in an earthen holding structure. These two systems differ by the number of days animals are confined which affects the total number of days of storage needed during the year. One liquid system is designed for a total confinement facility desiring 365 days of storage for all animal manure and sources of wastewater (feedlot run-off, silage leachate, and milking center wastewater). The second liquid-manure system is designed for a pasture-based dairy which confines animals for about 90 days of the year.
The final system handles manure as a solid, semi-solid, and excludes all sources of water. The covered holding structure excludes rainwater. Feedlot run-off, milking center wastewater, and silage leachate are diverted into a holding pond which is periodically land applied (90 days). The cost of these secondary structures are included in this analysis.
Recycling excreted nutrients is one benefit of manure that is easily quantified. A simple manure analysis or estimate of available nutrients can be used to value manure using current market prices of the nutrients it will replace. Shown in Table 23 are the expected quantities of each nutrient—nitrogen, phosphorus, and potassium—contained in each manure storage structure (one-time capacity). The total value of these nutrients are based upon the average price paid by Ohio farmers for commercial fertilizer: $0.29, $0.25, and $0.14 per pound of nitrogen, phosphorus, and potassium, respectively (Ohio Department of Agriculture, 2001). Animal manure nutrients can vary considerably and are dependent upon the animal and the feeding program. Laboratory testing of animal manure is recommended to better quantify available nutrients.
The nutrient benefits of manure nutrients are only realized when they are used as a substitute for purchased fertilizer. In many situations, excess nutrients have accumulated in the soil from years of over application. Nutrients beyond what are required for the growing crop will provide no additional yield. These excess nutrients should be considered an additional cost of production. That is, these nutrients could be better utilized where a crop response would be achieved by replacing additional purchased nutrients. Here it is assumed that manure nutrients are fully utilized, and the value of this nutrient resource reduces the cost of owning and operating the manure-handling system (Table 23). If manure nutrients are applied on soils already saturated with nutrients, the nutrient benefit will not be realized. Thus, the cost of owning and operating the manure-handling system increases.
| Table 23. Summary of Nutrient Benefits by System.* | ||||
| Nutrient | 365-Day Liquid System | 180-Day Liquid System | 90-Day Solid System | 365-Day Daily Haul |
|---|---|---|---|---|
| Total Nitrogen (lb)** | 30,300 | 15,150 | 7,575 | 30,300 |
| Total P2O5 (lb) | 15,200 | 7,600 | 3,800 | 15,200 |
| Total K2O (lb) | 17,200 | 8,600 | 4,300 | 17,200 |
| Total value | $12,100 | $6,050 | $3,025 | $12,100 |
| * Assumes a one-time capacity or annual value for daily haul. ** Assumes 50% of total nitrogen is organic, and one-third of organic nitrogen is available in the year it is applied. |
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Manure nutrient utilization requires that manure be land applied at critical times of the year. Ideally, this is when a growing crop is available to utilize available nutrients. This, in turn, requires that equipment be available for spreading (Table 24). Generally, manure is transported to the field by tractor-drawn spreaders, but manure can be pumped directly by means of irrigation equipment to a drag-line system. Tractor-drawn transport generally takes less equipment than does the drag-line. As more equipment is required, the annual cost of owning and operating the equipment also increases.
| Table 24. Equipment Requirements and Land Application Options. | ||
| Liquid Manure (broadcast) | Semi-Solid Manure (broadcast) | Liquid Manure (injection) |
|---|---|---|
|
|
|
The bottom line for most decisions is what it will cost. Table 25 summarizes the costs and benefits of each system outlined, using different storage capacities and land-application practices for a 100-cow dairy. Outlined are the annual costs associated with owning and operating the manure-holding structure, any secondary structures necessary to make the system operational, and equipment necessary for land application.
A range of values is given for those systems that are designed for less than one year storage; these values are based on the one-time capacity and annual use of the system. In other words, some operations may only store manure to satisfy the one-time capacity each year while others may use the system for year round confinement. For example, a solid manure system sized for 90-day storage is expected to cost about $19,000 per year, while this same system used for 365 days is expected to cost about $22,500 per year. Basically, this reflects the cost of equipment and labor needed to move the manure out of storage three additional times each year.
For each system, equipment has been identified (Table 24), and the cost of owning and operating this compliment has been estimated. Again, a range of values is presented and represents the estimated cost of owning and operating the equipment for the design capacity and for 365 days of storage. For example, the yearly cost of the equipment necessary to make the 180-day liquid-manure storage systems operational is expected to be between $20,500, if the system is filled only once per year, and $25,500, if it is filled and emptied twice per year.
Each manure-storage structure contains some quantity of manure nutrients. The value of these nutrients is shown and is calculated based on estimated nutrient content for the one-time volume of manure in storage. Manure nutrients were valued as commercial fertilizer and reduce the cost of owning and operating each system (system maintenance + annual cost of structure + application cost - nutrient value / 100 cows = per-cow cost of owning and operating the system).
Shown is a range of nutrient values (Table 25) reflecting the one-time storage capacity of the structure through full utilization, i.e., store manure 365 days a year. The value of manure nutrients assumes these nutrients are fully utilized by the growing crop. If manure nutrients are applied in excess of the crop needs and there is no benefit to storing these nutrients in the soil profile, the value of these nutrients is greatly reduced. In some situations, manure applied where soil nutrients are in excess will increase the potential that these nutrients will leach, move off-site, and become an environmental hazard.
| Table 25. System Summary. | ||||
| 365-Day Liquid System | 180-DayLiquid System | 90-DaySolid Manure | 365-DayDaily Haul | |
|---|---|---|---|---|
| One-Time Capacity1 | 1.4 M gal | 700K gal | 675 ton 2,700 ton | |
| System Maintenance2 | $500 | $275 | $817 | $100 |
| Annual Cost of Structure3 | $3,200 | $1,900 | $6,300 | $1,150 |
| Application Costs/Storage Capacity | ||||
| Tanker/spreader4 | $27,000 | $20,500-$25,500 | $11,900-$15,400 | $16,700 |
| Drag-line5 | $28,000 | $22,400-$24,618 | NA | NA |
| Custom applicator6 | $8,400 | $4,200-$8,400 | $1,300-$5,200 | NA |
| Nutrient Value/Storage Capacity | ||||
| All nutrients (N,P,K)7 | $12,100 | $6,050-$12,100 | $3,025-$12,100 | $12,100 |
| Cost to Own and Operate Storage and Handling System per Cow/Storage Period | ||||
| Tanker/spreader8 | $186 | $156-$166 | $104-125 | $59 |
| Drag-line9 | $196 | $125 | NA | NA |
| Custom applicator10 | $0 | ($15) - $3 | $2-$54 | NA |
|
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The liquid-manure system stores all sources of wastewater, run-off, silage leachate, and rainfall in an earthen holding pond. One system has storage capacity for 365 days and is expected to cost upwards of $200 per cow per year, depending on the land application option used (Table 25). Conversely, the liquid system that has 180 days of storage is expected to cost upwards of $166 per cow per year.
The semi-solid manure-handling system excludes all additional sources of water, including rainwater. However, this system has a high capital-investment requirement because of the building materials used, increased water exclusion requirement (roof), the need for a secondary wastewater treatment structure, and associated handling equipment. This system stores manure for 90 days and has an expected cost of about $125 per cow per year, depending on land-application options and the extent the structure is utilized.
Ohio Agronomy Guide. Ohio State University Extension Bulletin 472. 13th Edition. The Ohio State University.
Ohio State University Extension Bulletin E-2567. 1992. Tri-State Fertilizer Recommendations for Corn, Soybeans, Wheat and Alfalfa.
Klausner, Stuart D. 1989. Managing the Land Application of Animal Manures: Agronomic Considerations. Proceedings from the Dairy Manure Management Symposium. Syracuse, New York. Northeast Regional Agricultural Engineering Service. NRAES-31.
MidWest Plan Service (MWPS-18) Manure Characteristics.
U.S. Department of Agriculture, Natural Resources Conservation Service. 2002. Animal Waste Management Software.
Platt, Rutherford H. 2000. Managing New York City’s Watersheds. Environment June 01, page 15, University of Wisconsin Extension Service, 1999. Wisconsin’s Custom Rate Guide.
Rausch, Jon and Brent Sohngen. 1999. The Economics of Three Manure Handling Systems. AEX–02, Ohio State University Extension. Columbus, Ohio 43210.