Any confinement feeding operation that files a new manure management plan after Oct. 24, 2004, must file a manure management plan based on the Phosphorus Index.
The law calls new management plans “original” manure management plans and these plans are required for new or expanding sites, or if a site is sold or otherwise transferred. If a new manure management plan was submitted on or before Oct. 24, 2004, the operation will not be required to meet the Phosphorus Index until August 25, 2006, — even if the new construction occurs after Oct. 24, 2004.
The DNR developed a new form for manure management plans in August 2004, which incorporates the Phosphorus Index. The new form can be downloaded at http://www.iowadnr.gov/Portals/idnr/uploads/forms/5422021.pdf.
What will you need to develop your Phosphorus Index-based manure management plan that you didn’t need under the nitrogen-based plan?
1
Soil tests — Each field must be sampled at least once every four years. Existing soil tests may be used if they were taken within the last four years. For new manure management plans, if existing soil tests don’t meet the following requirements, they may still be used if new soil tests meeting the following requirements are taken within one year after the manure management plans are approved.
Each soil sample is required to have at least 10 soil cores distributed throughout the sampling area. Each core must include at least the top six inches of soil.
Soil samples must be analyzed at a lab certified by the Iowa Department of Agriculture.
If soil pH is 7.4 or more, soil phosphorus data from the Bray-1 extraction method cannot be used for the Phosphorus Index. The average soil test for phosphorus of a field is used in calculating the Phosphorus Index.
2
NRCS RUSLE2 — Utilize the erosion calculation for each field in the manure management plan. The calculator may be found on www.ia.nrcs.usda.gov.
NRCS Phosphorus Index — Determine the Phosphorus Index on each field that will be included in the manure management plan. Fields must be contiguous and cannot be separated by a road or river, creek, drainage ditch, etc. In calculating the sheet and rill erosion rate for the Phosphorus Index, the soil type used in the calculation must be the most erosive soil map unit that is at least 10% of the total field area.
Implementations date for Phosphorus Index-based plans
| Original manure management plan submitted | Phosphorus Index-based manure management plan update due |
| Prior to April 1, 2002 | First update after August 25, 2008 |
| Between April 1, 2002 and October 24, 2004 | First update after August 25, 2006 |
| On or after October 25, 2004 | Upon submittal |
As of August 25, 2004 the following new requirements went into effect for all manure management plans
1. Manure management plans must now be kept on site or at a residence or office of the owner or operator within 30 miles of the site.
2. The rule allowing crop yield and nutrient usage rate for corn to be used for legumes in the crop rotation has been deleted. If a manure management plan has already been developed for fall 2004 using a corn yield and nutrient usage rate for a legume crop, those rates can be used for manure application this fall.
3. The rule allowing manure applications above nitrogen crop usage rates (not more than the lesser of 1.5 times or the level providing the recommended level of phosphorus or potassium) if soil test levels for phosphorus or potassium levels are below recommended levels has been deleted. If a manure management plan has already been developed for fall 2004 using the 1.5 times nitrogen rate, those rates can be used for manure application this fall.
4. In addition to keeping records of the manure application rate, method, date and location of manure application, the following information used to calculate the manure application rate must be kept with the records:
a. Optimum yield for the planned crop
b. Type of nitrogen credits and amounts
c. Remaining crop nitrogen needed
d. Nitrogen content of the manure and first-year nitrogen availability of the manure
These additional items are in the manure management plan, so keeping a copy of the manure management plan with the records will meet these new recordkeeping requirements.
DNR changes policy on first-year nitrogen availability
DNR has also announced that it has changed its policy regarding first-year nitrogen availability in liquid swine manure. Before, DNR had recognized that not all nitrogen from manure was available the first crop year after application. Now, based on ISU Extension publication PM-1811, which states that “all of the nitrogen in swine manure from liquid handling systems is available the first year of application,” DNR’s policy is that new manure management plans filed after August 25, 2004 must use 100% nitrogen availability of liquid swine manure in the first year of application.
DNR has stated that manure management plans for existing operations may continue to use less than 100% first-year availability until the first Phosphorus Index based plan for the operation is due. However, despite DNR’s new policy based on ISU PM-1811, DNR rules also allow manure management plans to be prepared using information from other credible sources.
To use less than 100% first-year availability of nitrogen from manure in a new manure management plan, the DNR must now be provided with the source of that information and determine that the source is credible.
For more information on these topics, please contact the Iowa Pork Producers Association at 800-372-7675.