1. (1) A commercial fertilizer shall be deemed deficient if the analysis of nutrient is below the guarantee by an amount exceeding the values in the following schedule, or if the overall index value of the fertilizer is below 98%.

   1. (a) For DAP and MAP the investigational allowance for available phosphate shall be 0.70.
   2. (b) For TSP the investigational allowance shall be 1.53.
   3. (c) For guarantees not listed, calculate the appropriate value by interpolation.

   4. (d) The overall index value is calculated by comparing the commercial value guaranteed with the commercial value found.

      Example of calculation for a 10-10-10 grade found to contain 10.1% Total Nitrogen (N), 9.4% Available Phosphate (P 2 0 5 ), and 10.1% Soluble Potash (K 2 0). Nutrient unit values are assumed to be $3 per unit N, $2 per unit P 2 0 5, and $1 per unit K 2 0.

      10.0 units N	x 3 = 30.0
      10.0 units P 2 0 5	x 2 = 20.0
      10.0 units K 2 0	x 1 = 10.0
      Commercial Value Guaranteed	60.0

      10.1 units N	x 3 = 30.3
      9.4 units P 2 0 5	x 2 = 18.8
      10.1 units K 2 0	x 1 = 10.1
      Commercial Value Found	59.2

      Overall Index Value - (59.2/60.0) x 100 = 98.6%

2. (2) Secondary and micro plant nutrients shall be deemed deficient if the analysis of any element is below the guarantee by an amount exceeding the values calculated according to the following schedule:

   Guarantee Percent	Nitrogen (N)	Available Phosphate (P 2 O 5 )	Soluble Potash (K 2 O)
   	Investigational Allowance, percent
   4 or less	0.49	0.67	0.41
   5	0.51	0.67	0.43
   6	0.52	0.67	0.47
   7	0.54	0.68	0.53
   8	0.55	0.68	0.60
   9	0.57	0.68	0.65
   10	0.58	0.69	0.70
   12	0.61	0.69	0.79
   14	0.63	0.70	0.87
   16	0.67	0.70	0.94
   18	0.70	0.71	1.01
   20	0.73	0.72	1.08
   22	0.75	0.72	1.15
   24	0.78	0.73	1.21
   26	0.81	0.73	1.27
   28	0.83	0.74	1.33
   30	0.86	0.75	1.39
   32 or more	0.88	0.76	1.44

   Element	Allowable Deficiency
   Calcium	0.2 unit + 5% of guarantee
   Magnesium	0.2 unit + 5% of guarantee
   Sulfur	0.2 unit + 5% of guarantee
   Boron	0.003 unit + 15% of guarantee
   Cobalt	0.0001 unit + 30% of guarantee
   Molybdenum	0.0001 unit + 30% of guarantee
   Chlorine	0.005 unit + 10% of guarantee
   Copper	0.005 unit + 10% of guarantee
   Iron	0.005 unit + 10% of guarantee
   Manganese	0.005 unit + 10% of guarantee
   Sodium	0.005 unit + 10% of guarantee
   Zinc	0.005 unit + 10% of guarantee

   The maximum allowance when calculated in accordance to the above shall be one unit (one percentage point).

Authorizing statute(s): 80-10-301, MCA

Implementing statute(s): 80-10-206, MCA

History: NEW, Eff. 8/4/76; AMD, 2003 MAR p. 2421, Eff. 9/12/03; AMD, 2010 MAR p. 1795, Eff. 8/13/10; AMD, 2018 MAR p. 630, Eff. 3/31/18.