Farm/Ranch Self-Assessment System for Arizona

Manure Use and Management

Why should you be concerned?

The Arizona Farm*A*Syst worksheet entitled "Collection and Storage of Agricultural Animal Wastes and Wastewater" discusses the current laws that regulate Concentrated Animal Feeding Operations (CAFOs). These laws are in the form of Best Management Practices (BMPs), which are carried out through the use of Guidance Practices (GPs).

Arizona also has BMPs for the use of nitrogen fertilizer in agriculture. This worksheet covers information that will help you successfully apply manure and other organic wastes to cropland.

Livestock and poultry farms produce a lot of organic waste that can be recycled to enrich the soil. Some of these waste materials are high in nutrients. Livestock manure and milk parlor wastewater are especially high in nutrients.

Manure and other organic wastes are good for the soil if they are used properly. But they can cause pollution in the soil, water, and air if they are not managed wisely.

What can you do?

1. Follow the state mandated BMPs (by using the GPs best suited to your operation) for the use and disposal of animal wastes.

2. Find out the nutrient content of manure and organic wastes before using them. Adjust the amount of fertilizer you use based on soil tests, nutrients supplied by the manure, irrigation water, and crop needs.

3.Learn how to apply manure and other organic wastes safely on your land.

Worksheet Contents
Glossary
Fact Sheet
Assessment Worksheet
Resources

 

Glossary

Terms you need to know for Worksheet #8:

Application Addition of manure to soil.

Application methods Methods, rates of addition, and frequency of adding wastes to agricultural land that are required by BMPs.

Best Management Practices (BMPs) Nitrogen pollution minimization goals for regulated animal feeding operations. Methods, measures, or practices to prevent or reduce nitrogen pollution discharges. They include structural and nonstructural controls and operation and maintenance procedures. BMPs may be applied before, during, and after discharges to reduce or eliminate the introduction of pollutants into receiving waters.

Biosolids Means sewage sludge, including exceptional quality biosolids, placed on or applied to land as a soil amendment, conditioner, or fertilizer.

Crop plant needs Amount of water and nitrogen required to meet the physiological demands of the crop plant to achieve a defined yield.

Cropland Land that is planted and harvested with crops or improved pasture. Land suitable for manure application is referred to as "available cropland."

Cumulative pollutant loading rate Refers to the maximum amount of a pollutant that can everbe applied to a land application site.

Exceptional quality biosolids Biosolids that meet state-mandated pollutant concentrations, pathogen reduction, and vector attraction reduction requirements.

Guidance Practices (GPs) Technical practices used to achieve BMPs.

Incorporation Mixing of manure and soil after application, usually to a depth of 4-9 inches.

Liquid manure Manure with a moisture content over 90% (less than 10% dry matter). When well agitated, liquid manure will flow and can be pumped or moved by gravity.

Manure nutrient value Nutrient content of manure. Primary nutrients contained in manure and available for use by crops are nitrogen (N), phosphorous (P), and potassium (K).

Manure Animal feces and urine plus materials such as bedding and water.

Manure testing Laboratory analysis of a sample of manure for dry matter, nitrogen (N), phosphorous (P), potassium (K), and other nutrients.

Organic waste Any biological source of nutrients for crop production, such as manure, sewage sludge, septic tank sludge, industrial by-products, food processing wastes, milk parlor wastewater, silo seepage, and composted materials.

Solid manure Manure that usually has added bedding, will not flow, and can be stacked and handled by any equipment able to move bulk materials, such as a front end loader.

Spill Any accidental or unintentional loss of a material that has potential to harm the environment. This includes any loss from storage or transportation, or from application other than at the correct application rates, and on suitable sites.

Waste management plan Written management plan to handle farm wastes in a way that does not damage the environment. The plan should include manure and soil testing, proper application rates, and an emergency action plan in case of spills or system failures.

Wastewater sludge Solid portion of used water from a community, including industry, that flows to a treatment plant where it is separated out from the water during processing.

Fact Sheet

Overview

"The application of nitrogen fertilizer shall be limited to that amount necessary to meet projected crop plant needs." This statement is the first Best Management Practice (BMP) listed for managing nitrogen fertilizer use in Arizona agriculture. One of the Guidance Practices (GPs) that can be used to meet this BMP is GP 1.3: "Apply organic wastes to cropland."

When applied to cropland, animal manure can supply nitrogen and other nutrients necessary for plant growth. Arizona's soils are naturally low in organic matter. The use of animal manure on cropland can increase the tilth, aeration, water-and nutrient-holding capacities, infiltration rate, organic matter content, and microbial activity of soil.

Careful consideration of the following factors will help you successfully apply animal manure to your cropland:

1. Nutrient content of the organic wastes;

2. Rate of mineralization;

3. Weed seeds in manure;

4. Method of application and timing of incorporation; and

5. Salt content of manure.

Nutrient Content of the Organic Wastes

The amount of nitrogen found in animal manure depends upon the age and type of animal, feeding rate, type of ration, and how the waste was stored and handled both before and after being applied to the soil. To determine the amount of nitrogen applied, a farm operator must know both the amount of waste applied and its nitrogen content. A laboratory can analyze the manure for total nitrogen content, and the amount of waste applied can be determined by using a calibrated application system.

Rate of Mineralization

Before nitrogen and other nutrients in manure can be used by plants, soil microbes must break them down into forms that are readily available to plants. This process is called "mineralization."

The rate of mineralization is called a "decay series." Different types of waste will have different rates of decay. A decay series estimates the percentage of mineralization that will occur in the years following a manure application. For example, a decay series of 0.35, 0.15, 0.10, 0.075 means that following a dry corral manure application, 35% of the nitrogen is mineralized the first year, 15% of the residual (that which was not previously mineralized) is released in the second year, 10% in the third year, and so on. If the nitrogen concentration of a waste material and its decay series are known, the amount of waste needed each year to supply a constant amount of nitrogen can be calculated. Table 8.1 lists the approximate application rates of five waste materials needed to maintain an annual mineralization rate of 200 pounds nitrogen per acre.

Weed Seeds

Manures can contain seeds from weeds that can prove difficult to control. Because heat generated in manure stockpiles decreases the viability of weed seeds that may be present, the use of well-aged manures instead of freshly excreted materials will help reduce the likelihood of weed infestations from manure applications. Careful attention to the origin and quality of animal feedstuffs may also help reduce the severity of manure-transmitted weed problems.

Table 8.1. Input of five manure types needed to maintain annual mineralization rate of 200 pounds nitrogen per acre.

Annual application rate
tons per acre

Material and Decay Series Pounds of N/ton Year1 Year2 Year 3 Year 4 Year 5
Poultry manure, 1.6%N 0.90, 0.10, 0.075, 0.05 32 6.9
6.2 5.7 5.4 5.5
Fresh bovine waste, 3.5%N 0.75, 0.15, 0.10, 0.075
70 3.8 3.0 2.7 2.5 2.4
Dry corral manure, 2.5%N 0.40, 0.25, 0.06, 0.03 50 10.0
3.8 6.2 4.8 5.8
Dry corral manure, 1.5%N 0.35, 0.15, 0.10, 0.075 30 19.0
10.9 9.0 8.0 10.8
Dry corral manure, 1.0%N 0.20, 0.10, 0.075, 0.05 20 50.0 25.0 18.8 18.5 27.8
Source: Western Fertilizer Handbook,7th ed., 1985. California Fertilizer Association.


Method of Application and Timing of Incorporation

Animal manures and wastes should be injected or uniformly broadcast on cropland at recommended rates and then incorporated into the soil as soon as possible. Plowing or rototilling of the soil following surface applications of manure is recommended. Subsurface injection of fluid materials generally does not need additional tillage operations.

Immediate mixing with the soil will greatly reduce odor, nitrogen losses due to ammonia volatilization, and the potential for groundwater and surface water contamination resulting from runoff. Table 8.2 shows the effect of an increasing time lag between surface application and incorporation of animal manure.

Salt Content

Manures from concentrated animal feeding operations are usually high in salt content. Most dairy and feedlot manures contain 5 to 10% salt (50,000 to 100,000 ppm). Frequent and/or large (20 tons per acre) applications of manure to cropland increases the risk of salt injury to plants. Salt-sensitive plants such as lettuce, tree fruits and nuts are especially susceptible. The following management practices are recommended for applying animal manures to cropland:

1. Use well-aged manures rather than fresh manures taken directly from feedlots;

2. Apply up to 5 tons per acre of dry matter per year or 10 tons per acre every other year;

3. Use supplemental nitrogen fertilizers only as required based on tissue tests, plant performance and previous experience;

4. Plow or rototill manure into the soil, irrigate and wait at least 30 days before planting;

5. Do not apply manure where water penetration is poor; and

6. Monitor soil salinity and sodium levels by periodic soil tests.

Table 8.2 The effect of time lag between surface application and incorporation of poultry and other manures on the percentage of manure nitrogen available to crop plants.

Time of incorporation Percent of Manure Nitrogen Available
  Poultry Other
Immediate 75 50
After 2 days 45 35
After 4 days 30 30
After 7+ days 15 20
Source: Field Application of Manure, 1986. Pennsylvania Department of Environmental Resources.

Note: The information found in this fact sheet was excerpted from Nitrogen Fertilizer Management in Arizona, May 1991. University of Arizona Cooperative Extension.

Go to Assessment Worksheet

Resources

Arizona Department of Agriculture (ADA)
1688 W. Adams Street
Phoenix, AZ 85007
Dairy and Dairy Products Control: (602) 542-4189
Meat and Poultry Inspection: (602) 542-4971

Arizona Department of Environmental Quality (ADEQ)
Solid Waste Section
3033 N. Central Avenue
Phoenix, AZ 85012
(602) 207-4132

Arizona Department of Health Services (ADHS)
Vector and Zoonotic Disease Section
3815 N. Black Canyon Highway
Phoenix, AZ 85015
(602) 230-5912

Arizona Department of Water Resources (ADWR)
500 N. 3rd Street
Phoenix, AZ 85004
(602) 417-2400

Maricopa County Department of Environmental Services
Environmental Control
2406 S. 24th Street, Suite E-204
Phoenix, AZ 85034
(602) 506-3867

Maricopa County Department of Health Services
Vector Control Office
4707 E. Washington
Phoenix, AZ 85034
(602) 273-0895

University of Arizona Cooperative Extension
(See the "County Government" section of your local phone book for the office nearest you.)
Publications:
1. The Arizona Dairy Producers' Guide to Regulations and Technical Assistance September 1993. Free.
2. Nitrogen Fertilizer Management in Arizona May 1991. (191025). Cost: $10.00.

To order, call: (520) 621-1739
Or write to:
Publications Distribution Center
4042 N. Campbell Avenue
Tucson, AZ 85719

U.S. Natural Resources Conservation Service
(formerly Soil Conservation Service) or (SCS)
(See "Agriculture, Dept. of"--in the "United States Government" section of your local phone book.)
In Phoenix: (602) 280-8801

Thanks to . . .

Tom Doerge of the University of Arizona, Karl Meyer, Melanie Barton, and Mike Hill of the Arizona Department of Environmental Quality, and Harold Blume of The Natural Resources Conservation Service, who were the lead technical reviewers for this worksheet.