Fla. Admin. Code R. 62-640.500
(5) The NMP shall meet the requirements of this chapter and shall:
(f) Establish specific rates of application of biosolids based on nitrogen and phosphorus as well as procedures to land apply biosolids and all other nutrient sources to each application zone. The NMP shall address application rates for the period covered by the effective and expiration dates of the biosolids site permit, at a minimum. The final rate of biosolids to be applied to an application zone shall be not exceed the nitrogen-based rate and the phosphorus-based rate (the application rate shall not exceed the more restrictive of the two nutrient-based rates). The applicant may exceed the phosphorus-based rate if the applicant demonstrates the zone is comprised of native phosphatic soils and that applying at a higher rate is protective of water quality. As part of establishing the nitrogen and phosphorus-based application rates, the NMP shall include the following items.
1. The NMP shall identify the recommended crop nutrient needs for nitrogen and phosphorus (i.e. crop nutrient demand) for the crops to be grown on each application zone based on University of Florida Institute of Food and Agricultural Sciences (IFAS) recommendations or using the following values as a guide,
| Crop | Nitrogen: lbs/acre/growing season | Phophorus (P2O5): lbs/acre/growing season |
|---|---|---|
| Improved perennial grasses (i.e. maintenance fertilization of established pastures) ‒ Grazed | 160 | 40 |
| Improved perennial grasses (i.e. maintenance fertilization of established hayfields) – Hay or silage (assuming 4 harvests) | 320 | 80 |
| Cool season annual grasses (e.g. grazed small grains, ryegrass, fescue) | 160 | 80 |
| Warm season annual grasses (e.g. sorghum-sudan hydrid or pearl millet) ‒ Grazed | 160 | 40 |
| Warm season annual grasses (e.g. sorghum-sudan hydrid or pearl millet) ‒ Hay or silage (4 harvests) | 320 | 80 |
2. The NMP shall identify the current and planned plant production sequence or crop rotation for each application zone for the period of the biosolids site permit, at a minimum.
3. The NMP shall include realistic annual yield goals for each crop identified for each application zone, if applicable.
4. The NMP shall include the soil phosphorus storage “capacity index” (CI) and soil phosphorus results from the most recent soil fertility testing for each application zone. The CI and soil phosphorus results shall be based on Mehlich-3 extraction results for phosphorus, iron, and aluminum.
5. The NMP shall include a listing and quantification of all nutrient sources for each application zone.
6. The NMP shall include the percent water extractable phosphorus (PWEP) of each anticipated biosolids source (permittees may use a weighted average or estimated weighted average when biosolids applied to an application zone will be from multiple sources),
7. The crop nutrient demand phosphorus may be adjusted as given in a. and b. below, based on the soil phosphorus storage capacity index and the biosolids percent water extractable phosphorus (PWEP) when determining biosolids application rates. The adjustment to the crop nutrient demand phosphorus results in the amount of total phosphorus in lbs/acre that can be applied from biosolids (e.g., if doubling is allowed, a crop nutrient demand of 40 lbs P2O5/acre/year results in an allowed loading of 80 lbs total P2O5/acre/year).
a. When the PWEP of biosolids is less than 14%, one of the following may be used:
(IV) When the soil phosphorus capacity index is less than 0 mg/kg, the amount of phosphorus shall not be adjusted (i.e. the crop nutrient demand phosphorus equals the total amount of phosphorus allowed to be applied).
b. When the PWEP of biosolids is 14% or greater, the amount of phosphorus shall not be adjusted unless the the soil phosphorus storage capacity index is greater than 40 mg/kg, in which case the crop nutrient demand phosphorus may be increased by 50 percent to determine the amount of total phosphorus allowed to be applied.
8. When considering the availability of nitrogen in biosolids, once the amount of plant available nitrogen (PAN) to be supplied by biosolids has been determined (i.e. the crop nitrogen demand has been adjusted to take other sources of nitrogen into account), this amount may be multiplied by a factor of 1.5 (i.e. a 50 percent increase) to determine the amount of total nitrogen (TN) that may be supplied by biosolids. For example, if the crop nitrogen demand is 160 lbs PAN per acre per year and no other sources of nitrogen are applied, 240 lbs TN can be applied per acre per year by biosolids.
9. The calcium carbonate equivalency of any alkaline-treated biosolids and recommended lime application rates for each application zone,
10. Septage application rates for application zones with a soil capacity greater than 0 mg/kg shall be no more than 30,000 gallons per acre per year for septage containing food establishment sludge or no more than 40,000 gallons per acre per year for septage not containing food establishment sludge. Septage application rates for application zones with a soil phosphorus storage capacity index less than 0 mg/kg shall be no more than 12,000 gallons per acre per year. If septage is dewatered, these application rates shall be converted using the results of total solids monitoring of the dewatered septage.
11. The method of land application for each application zone; and,
12. The methodology and calculations used to determine the application rates for each application zone.
(6) For application sites located in geographic areas that have been identified by statute or rule of the Department as being subject to restrictions on phosphorus loadings (such as the Everglades Protection Area as set forth in Section 373.4592, F.S., the Lake Okeechobee watershed as set forth in Section 373.4595, F.S., Lake Apopka as set forth in Section 373.461, F.S., and the Green Swamp Area as set forth in Section 380.0551, F.S.), the NMP shall:
Rulemaking Authority 373.043, 403.051, 403.061, 403.062, 403.0855, 403.087, 403.088, 403.704, 403.707 FS. Law Implemented 373.4595, 403.021, 403.051, 403.061, 403.0855, 403.087, 403.088, 403.0881, 403.702, 403.704, 403.707, 403.708 FS. History–New 8-12-90, Formerly 17-640.500, Amended 3-30-98, 8-29-10, 6-21-21.