Developing a Plan for Land-Application of Nutrients from Poultry Litter
Nutrients in Poultry Litter
Availability of the Nutrients in the Litter
IntroductionPoultry litter (poultry manure and a bedding material such as sawdust, pine bark, or peanut hulls) is a good source of nutrients and organic matter for growing crops. Land application of poultry litter on farms has been the mainstay of effective and safe usage for years. Unfortunately, improper management of litter applications may cause nutrient enrichment and/or contamination of surface and ground water resources. The key to proper management is an understanding of the nutrients available in the litter, the nutrient requirements of the crops to be produced, and the potential for the litter and/or nutrients to reach surface or ground waters.
The Virginia General Assembly passed the Poultry Waste Management Act in 1999 to help assure environmentally-responsible handling of poultry litter. The act requires poultry growers with confined poultry feeding operations that have an annual production of 20,000 or more chickens or 11,000 or more turkeys to obtain a Virginia Pollution Abatement (VPA) permit. This permit governs the management of poultry waste and establishes requirements for proper nutrient management, waste storage, and tracking and accounting of poultry waste. The Poultry Waste Management Act also places regulatory requirements on "Poultry Waste Brokers," defined as "anyone, other than the poultry grower, who possesses more than 10 tons of poultry waste in any 365-day period and who transfers some or all of the waste to other persons."
Poultry growers covered by a VPA permit must, under the terms of the permit, have a nutrient management plan (NMP) that is approved by the Virginia Department of Conservation and Recreation. The NMP manages the amount, placement, timing, and application of manure, fertilizer, biosolids (treated sewage sludge), and other materials containing plant nutrients. It provides the operator with environmentally-sound guidance for managing all nutrient sources on a site-specific basis, taking into account the crops to be grown and the crop yield potential.
Nutrient Management Plans are not limited to VPA permit holders. Anyone with a farming operation in Virginia can receive free assistance in developing a nutrient management plan. For more information, contact your local Virginia Cooperative Extension Agent or your Department of Conservation and Recreation regional watershed office. The phone number for the local Extension Office can be found in the government pages of your phone book. Contact information for the DCR office serving your location can be found in the Appendix at the end of this publication.
This publication is intended to provide guidance on land-applying poultry litter in an environmentally-sound manner. The guidelines discussed herein are based upon the recommendations of the Virginia Departments of Environmental Quality and Conservation and Recreation. This material is not a substitute for an approved nutrient management plan (NMP), which is required for operations with a VPA permit.
Note: Several steps are required to calculate the appropriate poultry litter application rate for a given field and crop. The minimum data required for these calculations includes a soil test report from Virginia Tech where both the soil series (as listed on a NRCS soil survey map) and all of the crops to be grown on the field for a two-year period were listed when the sample was submitted to the lab. If this information was submitted, the lab report will include recommendations for nutrient applications to the field for all of the crops to be grown. With this data, and the worksheets provided in this publication, you can calculate the litter application rate(s) for your field. If you do not have a soil test report with data for the two-year rotation, you may wish to submit a new sample to the laboratory. Alternatively, contact your local Virginia Cooperative Extension Agent or your Department of Conservation and Recreation regional watershed office for assistance in making these calculations.
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Developing a Plan for Land-Application of Nutrients from Poultry LitterA properly designed land application plan includes a soil fertility program that uses litter to supply as much of the required plant nutrients as possible without over-supplying any nutrient. Nitrogen in poultry litter is readily converted to water soluble forms and nitrogen not taken up by growing plants can leach into ground water or runoff into surface water supplies. Therefore, the amount of nitrogen in a litter application should not exceed the nitrogen requirement of the crop being produced immediately following the application. Phosphorus is less soluble in water and less likely than nitrogen to move into ground or surface water. Therefore, the application rate for P2 O5 (phosphate) can be based on crop P uptake for a two-year crop rotation. However, research has shown that repeated over-application of phosphorus can result in phosphorus losses to surface waters, so, even though P is less mobile than N, repeated over-application of P can result in water pollution and must be avoided. Unfortunately, the relative supply of nutrients in poultry litter seldom matches crop needs. As a result, one calculates the litter application rate for both the crop N and P requirements and applies at the lower application rate. Commercial fertilizer is generally added in addition to litter to provide the nutrient that is lacking.
The DEQ Poultry Litter Storage and Utilization Fact Sheet provides guidance for poultry litter management on non-poultry farms (www.deq.state.va.us/regulations/xwaterregs.html). These DEQ guidelines suggest that for fields with a soil test of very high (VH) in phosphorus, poultry litter should be applied based on crop removal of phosphorus for a two-year rotation, as long as nitrogen is not over-applied to the crop following litter applications. It is further suggested that following litter application to very high testing soils, no additional phosphorus should be applied to these fields from any source, during the two-year rotation. For all other situations (i.e. soils testing low, medium or high in phosphorus), the DEQ guidelines recommend that litter may be applied to supply nutrients based on soil test recommendations. The procedures and steps outlined in this publication for calculating the rate of poultry litter application on non-poultry farms are consistent with the DEQ guidelines outlined in the Poultry Litter Storage and Utilization Fact Sheet.
Use the following steps to develop a land application plan:
- Determine the amount of nutrients in the litter.
- Estimate the availability of the nutrients in the litter.
- Collect soil samples to determine the existing nutrient levels in the soil.
- Estimate expected crop yield and corresponding crop nutrient requirements.
- Determine the litter application rate needed to match nutrient availability in the litter and the soil with the crop requirements.
- Determine fertilizer applications needed to provide nutrients not provided by litter.
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Nutrients in Poultry LitterThe nutrient content of poultry litter depends on many factors including poultry production practices and litter storage methods. Significant nutrient losses occur during storage; data from North Carolina indicates that stockpiled broiler litter typically contains less than half as much nitrogen as litter at the time of removal from the production house. Therefore, the litter nutrient content should be tested as close to the time of land application as possible.
Poultry growers holding a VPA permit are required to test the nutrient content of their litter at least once every three years. The VPA permit also requires growers to provide copies of the most recent litter analysis to anyone receiving 10 or more tons of litter within a year. If you receive litter from someone else, request a copy of their most recent litter analysis. Laboratory analyses of the litter should include total nitrogen, ammonium nitrogen (NH4-N), phosphorus (P2O5), potassium (K2O), and moisture content (% moisture).
If a laboratory analysis of the litter is not available, the values presented in Table 1 may be used to estimate nutrient content of litter. However, the actual nutrient value of the litter you apply can vary significantly from the average values presented. Variations greater than ten-fold have been reported between minimum and maximum litter nutrient values.
|Table 1. Average Values for Manure Tested in Virginia. Based upon samples received January 1989 - November 19921.|
|Manure Type2||Total N||NH4||P2O5||K2O|
|Dry Broiler litter||63||12||62||29|
|Dry Turkey litter||62||15||64||24|
|Layer or Breeder||36||9||65||24|
|1 Reproduced from Virginia Nutrient Management Standards and Criteria, Department of Conservation and Recreation, Commonwealth of Virginia, November 1995.|
2 Values in lbs of nutrient per ton except for liquid poultry, which is in lbs of nutrients per 1000 gal manure.
|Table 2. Average Values for Post-Phytase Poultry Manure Tested in Virginia. Based on samples analyzed from Jan. 2000 - February 2001. (Unpublished Data).|
|Manure Type1||Total N||NH4||P2O5||K2O||Moisture (%)|
|Poultry Without Litter||46||7.5||29||20||61|
|Poultry With Litter||69||13||52||44||29|
|1Except for moisture content, values are in lbs of nutrient per ton.|
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Availability of the nutrients in the litterPHOSPHORUS and POTASSIUM: The phosphorus and potassium in litter can be substituted for commercial fertilizer on a pound-for-pound basis. Use the value shown on the litter sample analysis (or from Table 1 if an analysis is not available) to estimate the phosphorus and potassium available in litter.
NITROGEN: The total nitrogen content of litter should not be substituted on a pound-for-pound basis for that in commercial fertilizer because some of the nitrogen in litter is in an organic form that is not readily available to plants and some is lost to the atmosphere as ammonia gas. Therefore, you must calculate the percentage of the manure nitrogen that is plant available.
Nitrogen (N) occurs in different forms in manure-both mineral and organic N. The mineral portion (approximately 20 percent of the total) is mainly present as urea, and in litter analyses is referred to as ammonium-N (NH4-N). Up to 75 percent of the mineral portion of the N is lost to the atmosphere as ammonia gas within seven days after spreading if the manure is not soil-incorporated. The actual portion of mineral N lost is determined by the time that elapses between spreading and soil incorporation. The decision to incorporate manure will depend on factors such as cropping system, cost of incorporation, cost of nitrogen, erosion hazard created by the tillage, and availability of equipment.
The organic N fraction gradually becomes available for crop uptake as the litter decomposes. The amount of N available in the first year from the organic fraction depends upon when the litter is applied (as a preplant application or as a winter topdress on winter annuals). When determining how much nitrogen is needed, the nitrogen available from previous litter applications (called "residual" nitrogen) is also considered.
Worksheet 1 helps you calculate the available nitrogen content of the litter and nitrogen credits from previous legume crops and manure applications. The greatest accuracy in determining nutrient content will be obtained from litter sample test reports. Otherwise, use the values in Table 1. However, be aware that you have the potential to significantly over- or under-apply nutrients if you use these data.
Unfortunately, there are a lot of data to be considered and a lot of calculations required to determine proper litter application rates. Two sets of example calculations are included in the Appendix of this paper to help you to understand the necessary calculations. If you are having difficulty with the Worksheets, contact you local Extension Agent or DCR representative for assistance.
Determining Soil Nutrient Levels and Expected Crop YieldSoil sampling determines the level of nutrients present in the soil. Soil samples from fields where litter is to be applied should be collected and analyzed at least once every three years for pH, phosphorus, potassium, calcium, and magnesium. Contact your local Virginia Cooperative Extension office for soil sampling materials and instructions on proper sampling methods.
When you submit a soil sample to the Virginia Tech Soil Laboratory, the submission form asks you to indicate the crops to be grown on the field over the rotation of interest and the soil series from which the sample was collected. If you submit samples every three years, list all crops to be grown in the three-year rotation. The soil series data comes from soil surveys conducted by the Natural Resources Conservation Service (NRCS). If you do not know the soil series in your field(s), your local NRCS office can help you determine them. Based upon this information, the report you receive from the Virginia Tech Soils Laboratory will provide you with recommendations for the amount of N, P, and K you should apply to each crop grown in the rotation. You need this data to complete Worksheet 2.
The soil test report also provides you with the Productivity Group for the first crop listed on the submission form. Unfortunately, the Productivity Group is a function of the crop grown, and the soil test report does not provide the Productivity Group for additional crops listed. The Productivity Group is needed for each crop to estimate the yield potential, and the yield potential is needed to estimate the crop phosphorus uptake and removal. If more than one crop is grown during the rotation, contact your local Virginia Cooperative Extension agent or DCR to determine the correct Productivity Group for each of the crops to be grown on the field.
Determining Crop Nutrient RequirementsTable 3 provides typical nutrient removal rates for various crops per unit of crop yield.
Table 4 provides estimates of yield for various non-irrigated crops as a function of soil productivity group. The soil productivity group is specified on the soil test from the Virginia Tech Soils Laboratory, if the form submitted with the soil sample indicated the soil series and crops to be grown. Remember, however, that the soil productivity group is different for different crops, so make sure the Soil Productivity Group you are using is for the crop of interest. If your crop(s) is not listed in Table 4, consult your local Virginia Cooperative Extension office or your regional DCR office for the yield estimates.
Land Application Conditions and SetbacksIn addition to determining the appropriate litter application rates, there are other considerations concerning when and where litter can be safely applied:
- Do not spread litter when the field is frozen, covered with snow or ice, or saturated with water. These conditions encourage runoff, which can carry nutrients to surface water.
- Application of litter on slopes greater than 15% should be avoided. However if litter is applied to pasture or hay fields with slopes greater than 15%, at least three inches of forage height should be maintained to reduce runoff potential.
- To ensure nutrient utilization, apply litter within 30 days of crop planting or follow the schedule presented in Table 5. Additional commercial fertilizer (especially nitrogen) should be applied as a split application from the poultry litter, either topdressed or sidedressed.
- Do not spread litter within the following buffer areas:
- 100 feet from wells or springs
- 50 feet from surface water (25 feet if incorporated)
- 10 feet from agricultural drainage ditches
- 200 feet from neighboring occupied dwellings unless the occupant waives or reduces the setback in writing
- 50 feet from sinkholes
- 50 feet from limestone outcroppings
- 25 feet from other rock outcroppings
Spreading Poultry LitterA nutrient management plan is only as good as its application. To spread poultry litter at the desired rate, it is necessary to calibrate your spreading equipment. This should be done at least annually and more frequently if the consistency of the litter is obviously different from the last batch used for calibration.
|Table 3. Typical Crop Nutrient Removal per Unit Yield1|
|Crop (unit yield)||N||P2O5||K2O|
|------------- (lbs of nutrient/unit yield) -------------|
|Barley Grain (bu)||1.25||0.375||0.25|
|Barley Silage (ton)||12.5||5||10|
|Corn Grain (bu)||1.1||0.35||0.27|
|Corn Silage (ton)||7.65||4.7||8.3|
|Cotton seed & lint (lbs)||0.04||0.013||0.01|
|Grain Sorghum (bu)||1||0.41||0.25|
|Rye Silage (ton)||16.6||6.67||21.8|
|1 Reproduced from DEQ Poultry litter storage and utilization fact sheet.|
2 Use hay rate if two or more cuttings occur. Use hay/pasture rate if only one cutting occurs and animals are then pastured.
|Table 4. Estimated yields in bushels (bu) or tons (T) per acre (A) for various non-irrigated crops for identified soil productivity groups based on VALUES.|
|Crop||Soil Productivity Group|
|Grain Sorghum (bu/A)||140||130||120||110||100||90||90||80|
|Tallgrass Hay (T/A)||>4.0||3.5-4.0||3.0-3.5||<3.0||NA||NA|
|Bermudagrass Hay (T/A)||>6.0||4.0-6.0||<4.0||NA||NA|
|Alfalfa Hay (T/A)||>6.0||4.0-6.0||<4.0||NA||NA|
|1Late season beans would be planted on or after 6/21 of that year.|
|Table 5. Poultry Litter Spreading Schedule. DEQ Poultry Litter Storage and Utilization Fact Sheet (www.deq.state.va.us/regulations/xqaterregs.html).|
**Except for Alfalfa and other warm season grasses.
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Record KeepingTo assure that the proper amount of nutrients is added to fields in future years, it is important to keep accurate records of litter and fertilizer applications. You should keep the litter nutrient analysis data, soil sample results, and copies of the worksheets used to determine litter and fertilizer application rates and spreader calibration. The following form will assist you in record keeping.
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ReferencesPoultry Litter Storage and Utilization Fact Sheet.
Virginia Department of Environmental Quality.
Virginia Nutrient Management Standards and Criteria. Nov. 1995.
Department of Conservation and Recreation
Division of Soil and Water Conservation
203 Governor Street, Suite 206 Richmond, VA 23219-2094
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AcknowledgmentsThe authors would like to express their appreciation for the review and comments made by Randy Shank, Retired Nonpoint Educational Coordinator, VCE; Susan Gay, Assistant Professor and Extension Engineer, Biological Systems Engineering; Robert "Bobby" Grisso, Professor and Extension Engineer, Biological Systems Engineering.
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If you have questions regarding litter application, contact your local Virginia Cooperative Extension Agent (listed in the phone book under County Government) or your local Department of Conservation and Recreation representative, as shown below:
DCR's regional offices
Abingdon (Tennessee-Big Sandy Watersheds Office): 252 W. Main Street, Suite 3, Abingdon, Va. 24210; phone: (276) 676-5528, fax: (276) 676-5527
Chase City (Roanoke Office): Bobby Long, 11632 HWY 15 S, Clarksville, VA 23927; phone: (434) 374-3648, fax: (434) 374-3648
Dublin (New River Watershed Office): P. O. Box 1506, Dublin, Va. 24084; phone: (540) 643-2590,fax: (540) 643-2597
Fredericksburg (Rappahannock Watershed Office): 2601 Princess Anne St., Suite 101, Fredericksburg, Va. 22401; phone (540) 899-4463; fax: (540) 899-4389
Henrico (James River Watershed Office): 3800 Stillman Pkwy., Suite 102, Richmond, Va. 23233; phone (804) 527-4484, fax (804) 527-4483
Staunton (Shenandoah Watershed Office): 44 Sanger Lane, Suite 102, Staunton, Va. 24401; phone: (540) 332-9991, fax: (540) 332-8956
Suffolk (Chowan-Albemarle Coastal Watersheds Office): 1548 Holland Road, Suffolk, Va. 23434; phone: (757) 925-2468, fax: (757) 925-2388
Tappahannock (York Watershed Office): P. O. Box 1425, Tappahannock, Va. 22560; phone: (804) 443-6752, fax: (804) 443-4534
Warrenton (Potomac Watershed Office): 98 Alexandria Pike, Suite 33, Warrenton, Va. 20186-2849; phone: (540) 347-6420, fax: (540) 347-6423
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Reviewed by Jactone Arogo, Extension Specialist, Biological Systems Engineering
Virginia Cooperative Extension materials are available for public use, reprint, or citation without further permission, provided the use includes credit to the author and to Virginia Cooperative Extension, Virginia Tech, and Virginia State University.
Issued in furtherance of Cooperative Extension work, Virginia Polytechnic Institute and State University, Virginia State University, and the U.S. Department of Agriculture cooperating. Edwin J. Jones, Director, Virginia Cooperative Extension, Virginia Tech, Blacksburg; M. Ray McKinnie, Administrator, 1890 Extension Program, Virginia State University, Petersburg.
May 1, 2009