EPIC Crop Codes

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Since version 8120, EPIC's operations file (ieops.dat) has required a "land use number" (LUN) in the second line.  This number is given in the second table below, but i_EPIC automatically calculates it given the crop, conservation practice, hydrologic condition and hydrologic group.

i_EPIC also uses these fields to calculate an operation's runoff curve number, if "Generate dynamic runoff curve numbers for operations" is checked in the control panel.  The tillage value may also effect this runoff curve number.

These tables show how i_EPIC calculates the runoff curve number and land use number for EPIC.

USDA Crop ID (different than Crop ID*) Name Land Use Type (see table below)
1 Soybeans Row Crops
2 Corn Row Crops
3 Grain Sorghum Small Grain
4 Winter Wheat Small Grain
5 Spring Wheat Small Grain
6 Durham Wheat Small Grain
7 Barley Small Grain
8 Oats Small Grain (Also duplicated as #16)
9 Sunflower Row Crops
10 COTS (cotton harvested with stripper) Row Crops
11 COTP (cotton harvested with picker) Row Crops
12 Peanut Row Crops
13 Rice Small Grain
14 Potato Row Crops
15 WPEA (winter peas) Other
16 Oats (Was mislabeled but ok inside i_EPIC.  Also duplicated as #8) Small Grain
17 ??? Other
18 Sorghum Hay Row Crops
19 Rye Small Grain
20 Range Pasture or Range
21 SPAS Pasture or Range
22 WPAS Pasture or Range
23 Pine tree Woods
24 Fallow Fallow
26 Fescue Pasture or Range
27 Red Clover Pasture or Range
29 Corn Silage Row Crops
31 Alfalfa Close Seeded Legume
35 Timothy Grass Pasture or Range (was Close Seeded Legume)
46 Permanent Pasture Pasture or Range
47 Cropland Pasture Pasture or Range
56 Brom Grass (used for CRP) Brom Grass
60 Grass Hay Close Seeded Legume

From Appendix E.2.A of the EPIC 3270 Manual, which references the National Engineering Handbook (U.S. Department of Agriculture, Soil Conservation Service 1972):

Land Use Type Conservation Practice Hydrologic Condition Land Use Number (LUN) Hydrologic Group A Curve Number Hydrologic Group B Curve Number Hydrologic Group C Curve Number Hydrologic Group D Curve Number
Row Crops None(0) Poor 2 72 81 88 91
    Good 3 67 78 85 89
  Contour (1), Strip (2) or Terrace (4) Poor 4 70 79 84 88
    Good 5 65 75 82 86
  Two or more of Contour, Strip and Terrace Poor 6 66 74 80 82
    Good 7 62 71 78 81
Small Grain None(0) Poor 8 65 76 84 88
    Good 9 63 75 83 87
  Contour (1), Strip (2) or Terrace (4) Poor 10 63 74 82 85
    Good 11 61 73 81 84
  Two or more of Contour, Strip and Terrace Poor 12 61 72 79 82
    Good 13 59 70 78 81
Close Seeded Legume None (0) Poor 14 66 77 85 89
    Good 15 58 72 81 85
  Contour (1), Strip (2) or Terrace (4) Poor 16 64 75 83 85
    Good 17 55 69 78 83
  Two or more of Contour, Strip and Terrace Poor 18 63 73 80 83
    Good 19 51 67 76 80
Pasture or Range None (0) Poor 20 68 79 86 89
    Fair 21 49 69 79 84
    Good 22 39 61 74 80
  Contour, Strip or Terrace or combination of two or more Poor 23 47 67 81 88
    Fair 24 25 59 75 83
    Good 25 6 35 70 79
Meadow (not used)     26        
Woods None (0) Poor 27 45 66 77 83
    Fair 28 36 60 73 79
    Good 29 25 55 70 77
Fallow All All 1 77 86 91 94
Brom Grass All All 21 49 69 79 84
Other All All 0 86 86 86 86