Sec. 370.8. Ranking of mineral soils

(a) Mineral soils shall be listed according to their soil productivity index and placed within one of ten soil groups. Each soil map unit representing a mineral soil shall be ranked according to its soil productivity index and placed by the commissioner into one of ten soil groups as follows:

Soil Productivity Index	Soil Group
90 – 100	1
80 – 89	2
70 – 79	3
60 – 69	4
50 – 59	5
40 – 49	6
30 – 39	7
29 or less - Marginal cultivated uses	8
Soils not suitable for pasture or other cultivated uses and not identified above or below	9
Marsh, wetlands and organics not farmed	10

(b) Two soil group subdivisions, determined according to the need to add lime to the soil in order to maintain soil capability, shall also be established for soil groups numbered 1 through 6.