Phosphorus index performance standard

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. (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. (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.