AGEN 2363 Notes: Chpt. 8. Cropping Systems.
I. General objectives of cropping system plans:
1. Reduce soil erosion
2. Improve soil organic matter and tilth
3. Recycle nutrients, keep nutrients from leaching
4. Add N to soil (legumes)
5. Benefits of crop rotations
II. Cropping system planning.
A. Crops. Consider short and long term effects on soil.
cereals, small grains
green manure crop
B. Soil fertility effects on soil productivity, tilth, and erosion resistance.
C. Plant population, row spacing, crop and variety effects.
D. Tillage systems, rotations. Examples, effects on soil erosion and water quality.
III. Planning crop rotation sequences - factors to consider:
1. duration? 2-4 years planning
2. single or multiple field rotation?
3. crops to be produced?
4. potential soil erosion?
Some examples for the mid-south:
corn corn - soybeans
cotton(no-till) cotton(no-till) cotton(conservation till) milo or corn
rice rice soybeans
soybeans-wheat(double crop) soybeans corn(no-till)
IV. Examples of other cropping systems and effects on soil erosion, water quality, soil
quality, and profitability.
1. sequential cropping (2-3 crops in same year) example in row crops is wheat-soybeans.
In vegetable crops: cabbage-cowpeas-broccoli or sweetcorn-squash
2. intercropping example: agroforestry, EX. pecan orchard with soybeans planted between
tree rows. Also hay crop alleys in loblolly pine plantings.
3. alley or strip-cropping
4. contour strip cropping (see recommended strip widths in relation to % slope).
5. buffer strip cropping
6. barrier strip cropping (in wind erosion prone regions)
7. border or riparian strips
V. Evaluation of cropping systems:
1. Crop yields, profits/losses?
2. Soil fertility, tilth?
3. Soil borne diseases? Weed shifts? Insect pest shifts?
4. Soil erosion, water quality?
Maintaining the productive potential of soil over the long term is a fundamental purpose of soil conservation.