Statutes, codes, and regulations
Montana Administrative Code
Department 4 - AGRICULTUREChapter 4.12 - AGRICULTURAL SCIENCES DIVISION
Subchapter 4.12.6 - Fertilizer Regulations
Rule 4.12.607 - INVESTIGATIONAL ALLOWANCES AND OVERALL INDEX VALUE

Mont. Admin. r. 4.12.607

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Current through Register Vol. 24, December 20, 2024
Rule 4.12.607 - INVESTIGATIONAL ALLOWANCES AND OVERALL INDEX VALUE
(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%.

Guarantee Percent

Nitrogen (N)

Available Phosphate (P2O5)

Soluble Potash (K2O)

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

(a) For DAP and MAP the investigational allowance for available phosphate shall be 0.70.
(b) For TSP the investigational allowance shall be 1.53.
(c) For guarantees not listed, calculate the appropriate value by interpolation.
(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 (P205), and 10.1% Soluble Potash (K20). Nutrient unit values are assumed to be $3 per unit N, $2 per unit P205, and $1 per unit K20.

10.0 units Nx 3 = 30.0
10.0 units P205x 2 = 20.0
10.0 units K20x 1 = 10.0
Commercial Value Guaranteed60.0

10.1 units Nx 3 = 30.3
9.4 units P205x 2 = 18.8
10.1 units K20x 1 = 10.1
Commercial Value Found59.2

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

(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:

ElementAllowable Deficiency
Calcium0.2 unit + 5% of guarantee
Magnesium0.2 unit + 5% of guarantee
Sulfur0.2 unit + 5% of guarantee
Boron0.003 unit + 15% of guarantee
Cobalt0.0001 unit + 30% of guarantee
Molybdenum0.0001 unit + 30% of guarantee
Chlorine0.005 unit + 10% of guarantee
Copper0.005 unit + 10% of guarantee
Iron0.005 unit + 10% of guarantee
Manganese0.005 unit + 10% of guarantee
Sodium0.005 unit + 10% of guarantee
Zinc0.005 unit + 10% of guarantee

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

Mont. Admin. r. 4.12.607

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

AUTH: 80-10-301, MCA; IMP: 80-10-206, MCA