Animal Waste and the Environment

by Cecil Hammond, Former Extension Engineer

Animal waste includes livestock and poultry manure, bedding and litter, plus such things as dairy parlor waste water, feedlot runoff, silage juices from trench silos and even wasted feed. These wastes can affect water quality if proper practices are not followed. These protective practices are very often referred to as best management practices (BMPs) and includes facilities or structures, management practices or vegetative cover.

Animal waste should be considered a valuable resource which, when managed properly, can reduce the need for commercial fertilizer. Such waste can add organic matter which improves water holding capacity and improves soil tilth. Animal waste can provide an economical source of nitrogen, phosphous and potassium as well as other nutrients needed for plant growth.

Waste from animal concentrations and/or manure storage areas which are not protected can wash into streams. Such overland flow of animal waste is commonly referred to as a non-point source (NPS) since the waste does not enter the streams from a point source or pipe.

Such waste in surface waters reduces oxygen in water and endangers aquatic life. The added nutrients produce excessive algae growth causing unpleasant taste and odors. Likewise, when this waste is allowed to seep into ground water the water quality is jeopardized. Nitrates in well water can be particularly dangerous to infants due to oxygen depletion in the blood.

In a speech made to the National Cattlemen's Association Board of Directors in March 1993, EPA Deputy Director David Davis stated that EPA data show NPS pollution is the largest remaining water quality problem in the United States. He further stated that data from the states attributes 41 percent of the total NPS pollution to agriculture. Further, data indicate that approximately one-third of the agricultural NPS pollution is caused by animal waste runoff from feedlots, holding areas and pastures.

Non-Point Source Pollution (NPS)

NPS pollutants are more difficult to control because they don't come from a clearly identifiable point such as a pipe or ditch. NPS pollution is caused, for example, from rain running over a field carrying pollutants in the water. We often cause NPS pollution without being aware of pollution.

The major NPS pollutants are:

• Sediment from improperly-managed construction sites, farm and forest lands, road cuts and eroding stream banks.
• Nitrogen and other nutrients from farm land, forest, residential areas, septic systems, golf courses, etc.
• Bacteria from livestock, pet waste, wildlife and faulty septic and sewage systems.
• Salt from irrigation, acid drainage from mines and highway salt treatment.
• Pesticides from farms, forest, residential areas, etc.
• Oil, grease and other chemicals from urban runoff, energy production and improper disposal of used oil.

Managing Manure and Waste

This includes soil testing and testing the waste in order to match the crop needs to the nutrients available. This also means a large enough storage system will be needed to allow waste to be applied when the most benefit will be realized by the crops from the available nutrients. Waste can be stored in stack houses as a solid or in holding ponds or anaerobic lagoons as a liquid. Having storage is essential to allow land application when needed by plants rather than having to apply to saturated fields or pastures where runoff is more likely. The storage and handling methods along with the method of field application can make a considerable difference in plant nutrients available.

Some best management practices (BMP's) follow:

• Store manure to allow timely applications and reduce nutrient losses from runoff.
• Use manure to reduce fertilizer cost.
• Apply manure to crops which can benefit from the nutrients.
• Do not apply on frozen ground or when runoff potential is high.
• Avoid spreading near streams, wells, and ponds or sinkholes.
• Use conservation practices which minimize runoff and erosion on land where waste is applied.
• Calibrate application equipment.
• Inject or incorporate manure into the soil.
• Analyze waste before spreading and soil test to balance nutrients to crop needs.
• Do not allow lagoons to overflow and collect runoff from concentrated animal operations for later land application to protect streams.
• Protect wetlands which serve to clean up water.
• Add gutters to livestock housing and keep rainwater out of the waste stream.
• Divert runoff from land above the barnyard.
• Divert barnyard runoff away from streams and ponds.
• Add vegetated filter strips along streams to trap sediment and other pollutants.
• Exclude livestock from sensitive areas along stream banks and wetlands.
• Provide stream crossings and access for drinking.
• Collect and dispose of silage juices with the disposal system you use for manure.
• Use planned grazing in which two or more units are alternatively grazed and rested to improve forage production, maintain vegetative cover and retain waste on the land.
• Convert to livestock confinement systems such as dairy freestalls with flush gutters where all the waste is confined and recycled onto the land.
• Since most farms have fuel storage, check fuel storage tanks for spills and leaks and make sure your farm meets regulations.
• Use solids separation or settling basins to make liquid waste systems more liquid and easier to apply or recycle.
• Adapt new technology which is environmentally friendly such as composting poultry mortalities.

Be Aware

How you manage animal waste can impact water quality. Waste from animal concentrations and unprotected manure storage areas can wash into streams. Steep and unprotected slopes, poor soil conditions, lack of vegetative cover, heavy rains and the proximity to streams are some of the factors which play a role in potential environmental damage. If surface or ground waters are being compromised on your farm, seek help and make changes.

Planning an Animal Waste Management System

Planning proper waste handling will not only help protect the environment, it can improve the overall farming operation and overall cash flow. For example, dairymen who add freestalls not only provide for closed loop waste handling but also provide shade, feeding and loafing areas for the animals. These improvements translate into more milk (and easier management) which normally pays for the construction cost in 3 to 5 years. Adding cow mats in freestalls not only saves time and money but keeps the bedding in the stalls and out of flush gutters, making the liquid manure systems more manageable. Liquid manure systems are very popular, primarily because of the degree of automation. If solids are removed, the liquid waste is considerably easier to pump and recycle for flushing gutters.

Table 1 shows the nutrients in animal waste (N, P, K) for various animals based upon a 1,000 pound animal unit over a period of one year. Data for Tables 1-3 are taken from Midwest Plans Publication Number #1 (1983 Edition).

Table 1. Annual Pounds of Nutrients in Manure as Excreted per 1000 Pounds Liveweight
	Dairy Cow	Beef Feeder	Swine Feeder	Laying Hen	Broiler
Nitrogen, N	150	124	164	263	423
*Phosphate, P2O5	60	91	124	232	216
*Potash, K2O	118	106	132	136	158
* Elemental P & K conversion can be made as follows: To convert P2O5 to elemental P, multiply by 0.44; and to convert K2O to elemental K, multiply by 0.83.

Method of Handling and Land Application

Average nitrogen losses which occur with various manure handling and storage methods are given in Table 2.

Table 2. Approximate Nitrogen Losses from Manure as Affected by Handling and Storing Methods
Handling, Storing Methods	Nitrogen Loss*
Solids Systems:
Manure Pack	35%
Poultry Litter	35%
Liquid Systems:
Anaerobic Pit	25%
Oxidation Ditch	60%
Lagoon	80%
* Based on composition of manure applied to the land vs. composition of freshly excreted manure.

Table 3 shows average nitrogen losses within four days using various methods of application.

Table 3. Approximate Nitrogen Loss from Manure to the Air as Affected by Application Method
Application Method	Type of Manure	Nitrogen Loss*
Broadcast without cultivation	Solid	20%
	Liquid	25%
Broadcast with cultivation**	Solid	5%
	Liquid	5%
Knifing	Liquid	5%
Irrigation	Liquid	30%
* Percent of total nitrogen in manure applied that was lost within 4 days after application ** Cultivation immediately after application.

While the data above may be useful as approximation, laboratory analysis of the waste and soil test on your land is the best approach.

Need for Waste Management

More and more state and federal governments are requiring nutrient management plans, tougher regulations and more accountability in waste handling. However, most will agree voluntary control is less costly and more productive than governmental control and regulations. To make it work, every one of us needs the commitment and dedication. A few flagrant offenders gives all of agriculture a bad name. Regulations are one way to help ensure that everyone knows what the minimum standards are. See Extension Circular 819-11, Georgia Agricultural Waste Regulations.

Water is the world's most abundant resource, but only one percent of water is suitable for drinking. The average person in the U.S. uses about 180 gallons of water per day. We all live in a watershed down stream from someone else.

Where to Get Help to Implement Changes

Contact your local agencies such as the Extension Service, Soil Conservation Service (SCS) and Agricultural Stabilization and Conservation Service (ASCS) for further information and assistance.

Growing concern about waste handling coincides with the public concern about environmental quality. Following best management practices can improve the environment and reduce liability for farmers.

The University of Georgia and Ft. Valley State College, the U.S. Department of Agriculture and counties of the state cooperating. The Cooperative Extension Service offers educational programs, assistance and materials to all people without regard to race, color, national origin, age, sex or disability.

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Gale A. Buchanan, Dean and Director

last updated: 25 February 1997
http://www.bae.uga.edu/extension/pubs/c827-cd.html
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