328-4
Appendix 1
Determination of Soil Condition Index
Organic content in the root zone of the soil is very important to providing a favorable moisture and nutrient environment for plant growth. Organic content on the surface and upper two inches is extremely important to managing wind and water erosion with the upper 0.6 inch being the most important. Organic content is also important in soil tilth, infiltration of precipitation and tie-up of contaminants.
The soil condition index procedure provides a means for predicting the impact of the cropping system on the organic matter levels in the soils. A soil condition index of (0) or greater for the crop rotation indicates maintenance or improvement of soil quality.
Calculating the soil condition index: For each year in the crop rotation, determine the residue component value, tillage component value, and erosion component value for each crop. Total the values for the residue component, tillage component and erosion component for each year. Add the index values for all year and divide by the number of years in the rotation to get the soil condition for the rotation.
Soil condition index: Crop residue component and tillage component, and erosion component.
NRCS, SC
August, 2001
328-5
Appendix 1
A. Crop Residue Component
1. Annual Field Crops
______
Low Medium High
Crop Yield Value Yield -Value Yield -Value
______
Barley <40 bus. (-0.25) 40-60 bus. (0.20) >60 bus. (0.60)
Corn (grain) <60 bus. ( 0.18) 100 bus. (0.90) 150 bus. ( 1.8)
Corn (silage) Low (-0.50) Medium (-0.40) High (-0.25)
Cotton 250 lbs (-0.60) 500 lbs. (-0.10) 750 lbs. ( 0.25)
Grain Sorgham 2000 lbs. ( 0.15) 3000 lbs. ( 0.75) 5000 lbs. ( 1.5)
Sorgham (silage) Low (-0.50) Medium (-0.40) High (-0.25)
Oats 35 bus. (-0.20) 60 bus. ( 0.20) 80 bus. ( 0.25)
Peanuts 2000 lbs. (-0.25) 3000 lbs (0) 4000 lbs. ( 0.25)
Peanuts (Resi-
due removed) (-0.65) (-0.60) (-0.50)
Rye 20 bus. (-0.35) 30 bus. ( 0.25) 50 bus. ( 0.60)
Soybeans >20 bus. (- .25) 20-30 bus. (0) >30 bus. ( 0.25)
Tobacco <1700 lbs. (-0.45) 1700-2500 lbs. (-0.30) >2500 lbs. (-0.20)
Vegetable Crops Low (-1.25) Medium (- 1.0) High (-0.75)
Wheat <30 bus. (-0.20) 30-50 bus. (0.25) >50 bus. ( 0.75)
______
- Cover and green manure crops and annual forage crops are credited by adding .025 to the residue index for each 100 lbs. of above ground growth produced and left on the field.
- Residue from weeds and other vegetation in summer idle fields can be credited the same as residue from cover crops (+.025) for every 100 lb. Residue).
- Organic mulch such as manure, small grain straw, etc. can be credited by adding 0.5 for each ton of mulch added to the field.
NRCS, SC
August, 2001
328-6
Appendix 1
2. Double Cropping
______
Low Yield - Medium Yield - High Yield -
Crops Value Value Value
______
Small Grains - Soybeans (0) 0.75 1.25
Small Grain (Residue Removed) -
Soybeans (-0.25) (0.25) (0.75)
Small Grains - Grain Sorghum (1.50) (2.00) (2.50)
Small Grain (Residue Removed) -
Grain Sorghum (1.25) (1.75) (2.25)
Small Grain (silage) -
Sorghum (silage) (-0.25) (-0.15) (0)
______
3. Perennial Crops (Included in cropping sequence)
______
Duration of Perennial Soil condition indices for perennial crops
Crops in Rotation harvested as hay, silage, or green chop ___
Grass Legume Grass and Legume ___
1 Year +1.00 +1.00 +1.00
2 Years +3.00 +2.50 +3.00
3 Years +4.00 +3.00 +4.00
4 Years +4.50 +3.50 +4.50
5 or more Years +5.00 +3.75 +5.00
______
NRCS, SC
August, 2001
328-7
Appendix 1
B. Tillage Component
______
Mechanical Chemical Combination
weed weed mechanical/
Tillage System control control chemical
______
Conservation tillage
No-till N/A +1.0 N/A
Reduced till 0 + .50 + .25
No-till (after 3 continuous years) 1.50
Conventional tillage
1 - 2 primary till - 1.0 - .50 - .75
3 - 4 primary till - 2.50 - 1.50 - 2.0
4> primary till - 2.75 - 1.75 - 2.0
______
C. Erosion Component
______
Sheet and rill Fibrous Tap
erosion rate rooted rooted
______
0 - 3 tons 1.0 1.0
3 - 5 tons .75 .75
5 - 8 tons 0.0 -1.0
8 - 10 tons -1.0 -1.5
11 - 15 tons -1.5 -2.0
16 - 20 tons -2.0 -2.5
20> -2.5 -3.0
______
NRCS, SC
August, 2001
328-8
Appendix 2
Pest Control with Crop Rotations
A. Insect and Disease Control
Some insect and disease pests may be reduced or controlled by crop rotations. These organisms typically have a narrow group of host plants. In contrast crop rotations may provide little benefit for control of insect and disease organisms with a wide range of host plants. The following table identifies preferred rotation crops for control of the specified problem pest. Monoculture or rotations with crops other than those specified, including idle fields, may result in persistence or worsening of the pest. Insect or disease pests not listed typically are not affected by crop rotations.
______
CROP INSECT OR DISEASE SUGGESTED ROTATIONS
______
Alfalfa Anthracnose, Crown and stem rot Allow 3 - 4 years after alfalfa and
other forage legumes.
Corn Helminthosporium Leaf blights Rotations with soybeans, cotton, or
other non-grass type crops.
Corn virus diseases Eradication of Johnsongrass.
Sting nematodes Tobacco and watermelons are tolerant.
Fall armyworm Can be aggravated by Johnsongrass or
bermudagrass.
Stalk rots Rotate with non-grass crops.
Cutworms Following newly broken sods or idle
fields may be a problem.
Sugarcane beetle Following weedy sods especially in
poorly drained fields may be a problem.
Cotton Ascochyta blights, bacterial leaf Rotations with grasses or grass type
spots, angular Verticullium wilt crops.
Grain Sorghum Anthracnose Helminthosporium Avoid rotations with corn, sudangrass
and Johnsongrass.
NRCS, SC
August, 2001
328-9
Appendix 2
______
CROP INSECT OR DISEASE SUGGESTED ROTATIONS
______
Peanuts White mold, pod rot or leaf spot 3 or 4 years rotations from peanuts -
plant non-legume the year prior to
peanuts.
Black rot Rotate with corn or pasture grass
for at least 2 years.
Small Grain Helminthosporium leaf blights Rotations with non-small grain type
disease of oats and barley crops.
Anthracnose of rye Rotation with non-small type crops.
Soybeans Sting nematode Tobacco and watermelons are tolerant.
Avoid rotations with cereals, cotton
and peanuts.
Root-knot nematodes Rotate with corn or cotton.
Soybean cyst nematodes Rotations with grasses and grass type
crops. No-tillage is beneficial.
Soybean brown spot disease 1 year rotation with non-legumes.
Soybean red crown rot Rotations with grasses and grass-type
crops.
Bacterial leaf spots and blights 1 year rotation from soybeans and
other bean or pea crops.
Southern stem blight Rotation with grasses or grass-type
crops.
Frogeye leaf spot 1 or 2 year rotation from soybeans
and other bean or pea crops.
Anthracnose Rotations with non-legumes.
Purple seed stain Rotation from bean or pea crops.
Soybean pod blight Rotations with grasses or grass-type
crops.
NRCS, SC
August, 2001
328-10
Appendix 2
______
CROP INSECT OR DISEASE SUGGESTED ROTATIONS
______
Sweet Potatoes Melanstus communis Wireworms Avoid idle fields.
Scurf and black rot A 3-year rotation from sweet potatoes.
White grubs Avoid fields with heavy residue.
Tobacco Granville wilt Rotations with soybeans.
Black shank Rotation of 2 - 3 years with any crop
other than tobacco.
Root-knot nematodes Rotations with corn or cotton.
Tomatoes Bacterial wilt Rotate for at least 5 years to nonhost
crops. Avoid following idle weedy
fields.
Early blight Late blight Avoid monoculture or rotations with
potatoes and/or eggplant.
Cucurbits Anthracnose Gummy stem blight Rotation to non-cucurbits for 2 years.
Fusarium wilt of watermelons Rotation to non-cucurbits for
5 - 7 years.
B. Weed Control
- Persistent broadleaf weeds typically are more easily controlled in grass-type crops.
- Persistent grass weeds typically are more easily controlled in broad leaf crops.
- Herbicide carry-overs may limit acceptability of some crop rotations.
NRCS, SC
August, 2001