Section NR 151.04 - Phosphorus index performance standard(1) All crop and livestock producers shall comply with this section.(2)(a) Croplands, pastures, and winter grazing areas shall average a phosphorus index of 6 or less over the accounting period and may not exceed a phosphorus index of 12 in any individual year within the accounting period.(b) Except as provided under sub. (3), for purposes of compliance with this section the phosphorus index shall be calculated using the version of the Wisconsin Phosphorus Index available as of January 1, 2011. Note: The Wisconsin Phosphorus Index is maintained by the University of Wisconsin department of soil science and can be found at http://wpindex.soils.wisc.edu/.
Note: Soil test phosphorus concentration may be used to help identify fields that are high priority for evaluation with the Wisconsin Phosphorus Index. For example, croplands with soil test phosphorus concentrations of 35 parts per million or greater should be given higher priority for evaluation.
Note: Best management practices developed by the department of agriculture, trade and consumer protection may be used alone or in combination to meet the requirements of this section.
(c) The accounting period required under par. (a) shall meet the following conditions: 1. The accounting period shall begin once a nutrient management plan meeting the requirements of s. NR 151.07 and s. ATCP 50.04(3) is completed.2. During the first 8 years of implementation of this standard by a producer, computation of the phosphorus index may be based on a combination of planned crop management and historic data. Planned crop management data is based on projected management and crop rotations. Historic data is based on management and crop rotations that have actually occurred.3. Once the nutrient management plan under s. NR 151.07 and s. ATCP 50.04(3) is developed, historic data shall be used for each year as it becomes available.(3) If the phosphorus index is not applicable to a particular crop or situation, an equivalent calculation approved by the department shall be used to meet the requirements of this section. Note: The requirement provides for alternative methods to calculate a phosphorus index. Some strategies for assessing and reducing phosphorus index values, algorithms, and software can be found at http://wpindex.soils.wisc.edu/.
(4) Producers may not apply nutrients or manure directly, through mechanical means, to surface waters as defined in s. NR 102.03(7).(5) The phosphorus index requirement under sub. (2) (a) first takes effect for pastures beginning July 1, 2012.Wis. Admin. Code Department of Natural Resources NR 151.04
CR 09-112: cr. Register December 2010 No. 660, eff. 1-1-11; correction to (4) made under s. 13.92(4) (b) 7, Stats., Register December 2010 No. 660.