15.20.08.06

.06 Nutrient Management — Phosphorus Site Index.

A. Except as provided in §F of this regulation, if the soil sample analysis results show a phosphorus fertility index value of 150 or greater, the Phosphorus Site Index, as provided in the Maryland Nutrient Management Manual, Section II-C1, shall be used to determine the potential risk of phosphorus loss due to site characteristics.

B. Low Risk of Potential Phosphorus Loss. If the risk for potential loss of phosphorus from the site is low according to the Phosphorus Site Index, nutrient recommendations by the consultant or certified farm operator may use nitrogen plant needs as the limiting factor.

C. Medium Risk of Potential Phosphorus Loss.

(1) Except as provided in §C(2) of this regulation, if the risk for potential loss of phosphorus from the site is medium according to the Phosphorus Site Index, nutrient rates shall be based on nitrogen plant needs as the limiting factor not more than 1 out of every 3 years. Phosphorus rates for the other 2 years shall be limited to the expected amount removed from the field by the planned crop or plant rotation immediately following the phosphorus application, not to exceed two crops, or the amount indicated by soil testing, in accordance with the recommendations described in the Maryland Nutrient Management Manual, Section I-B, whichever is greater.

(2) Nutrient recommendations may use nitrogen plant needs as the limiting factor if BMPs are implemented by the operator before or during the application of additional phosphorus that address site or management characteristics which, according to the outcome of a recalculation using the Phosphorus Site Index, reduce the risk of phosphorus loss to low.

D. High Risk of Potential Phosphorus Loss.

(1) Except as provided in §D(2) of this regulation, if the risk for potential loss of phosphorus from the site is high according to the Phosphorus Site Index, phosphorus rates shall be limited to the expected amount removed from the field by the planned crop or plant rotation immediately following the phosphorus application, not to exceed two crops, or the amount indicated by soil testing, in accordance with the recommendations described in the Maryland Nutrient Management Manual, Section I-B, whichever is greater.

(2) If BMPs are implemented by the operator before or during the application of additional phosphorus that address site or management characteristics which, according to the outcome of a recalculation using the Phosphorus Site Index, reduce the risk of phosphorus loss to medium, nutrient rates may be based on nitrogen plant needs as the limiting factor not more than 1 out of every 3 years. Phosphorus rates for the other 2 years shall be limited to the expected amount removed from the field by the planned crop or plant rotation immediately following the phosphorus application, not to exceed two crops, or the amount indicated by soil testing, in accordance with recommendations described in the Maryland Nutrient Management Manual, Section I-B, whichever is greater.

E. Very High Risk of Potential Phosphorus Loss.

(1) Except as provided in §E(2) of this regulation, if the risk for potential loss of phosphorus from the site is very high according to the Phosphorus Site Index, no additional phosphorus may be applied.

(2) If BMPs are implemented by the operator before or during the application of additional phosphorus that address site or management characteristics which, according to the outcome of a recalculation using the Phosphorus Site Index, reduce the risk of phosphorus loss to high, recommended rates of application of phosphorus shall be limited to the expected amount removed from the field by the crop or plant harvest, or the amount indicated by soil testing, in accordance with recommendations described in the Maryland Nutrient Management Manual, Section I-B, whichever is greater.

(3) The operator shall consider the implementation of management practices and technologies that are effective in lowering the risk of phosphorus loss, based on research and demonstration of the University of Maryland, or other land grant university, or by the United States Department of Agriculture, Natural Resources Conservation Service, National Planning Procedures Handbook and practice standards adopted for Maryland.

F. If the soil sample analysis results indicate a phosphorus fertility index value of 500 or greater, no phosphorus may be applied.