CONTROLLING EROSION ON THE FARMSoilsAg I

Objectives* Explain how land capability classes relate to

wise soil use Describe the main vegetation methods

farmers use to control water-caused erosion Describe the main mechanical methods

farmers use to control water-caused erosion Describe the control measures farmers use

to control wind-caused erosion Explain why soil erosion control should be

important to every farmer

Land Capability and Land Use

Review of Land Capability Classes

I-IV suitable for cultivation V-VIII considered not usable for

cultivation

Control Measures for Water Caused Erosion

Vegetative Control Cover crops

Close growing Improve organic matter content, structure

and tilth of the soil Green-manure crops

Cover crops that have been tilled under Close growing grasses and clovers work

best for both cover and green-manure crops

Crop Rotation Orderly and repeated sequence of

different crops grown on the same field 3 year rotation- Corn, soybeans, wheat 4 year rotation corn, cotton, oats, hay or

pasture Sequence is repeated every 3-4 years Many possible rotations to use with

success

Advantages of Crop Rotation

Soil tilth is better maintained Soil water absorption is improved Erosion danger is lessened Organic matter content is increased If a legume is included, nitrogen fixation

helps supply that costly plant nutrient Soil tillability is improved Moisture storing capacity of the soil is

improved

Strip Cropping The production of alternating bands of different

crops Used to control both wind and water erosion Sloping lands

Strips are laid out either on the contour or across the prevailing slope

Typical strip cropping scheme alternates row crop, hay, row crop Example- 3 year rotation of corn-soybeans-hay the

strips of hay would make up 1/3 of the field while the corn or soybeans would make up the other 2/3. Strips would be alternated annually

Permanent Strip Cropping Variation is permanent strips of cover crop,

pasture, or hay alternated with a row crop with or without a crop rotation system

Effect is to provide bands of heavier vegetation alternated with row-cropped bands. Heavier vegetation

Increases the rate of water absorption Holds the soil in place better Cuts down on gullying Improves soil tilth in the band Also serves the slow down run-off to lessen its cutting

power

Grassed Waterways Widely used throughout the world Best used in a fields natural draws and

drainageways In terraced or contour fields used as a

release for the water from the row or terrace

Construction of Grassed Waterways

3 shapes Trapezoidal Triangular Saucer

Most common is saucer shaped

Grassed Waterway Shapes

Best Grasses for Grassed Waterways

Fescue Bermuda Bluegrass When planting the grasses the seedbed

should be seeded at 2 to 3 times the normal rate

Mechanical Erosion Control

Conservation Tillage Any tillage system that is economically practical for

crop production and aids in soil and water conservation

Techniques differ across the country Common techniques

Minimum tillage No till Zero till Stubble plant Chisel plowing Lot planting Strip tilling

Advantages Less energy and time are required as the

amount of tillage is decreased Soil moisture levels increase with the

increased soil organic-matter level Soil erosion is better controlled

Disadvantages Increase in weed, insects and disease

problems Heavier fertilization may be required due

to crop residues tying up soil nitrogen Increased herbicide use is needed to kill

weeds Exsisting equipment may not be well

suited to conservation tillage

Contour Farming Plowing “around” the field Rows act like small damns to slow run-off Rows should not be laid out straight

across the slope, they should run downhill slightly to allow runoff to be conducted in the desired direction

Also works to control wind erosion if rows are plowed across the prevailing winds, then each row of crop acts as a mini shelterbelt

Terraces Larger surface channels constructed on

the contour with a controlled rate of fall Designed to accept runoff and conduct it

across the slope to some protected area Needed on slopes that exceed 2% and

where the slope is over a few hundred feet long

Terraces

Controlling Wind Erosion

Windbreaks Trees or shrubs planted across the

prevailing winds Reduce the cost of heating and cooling

the home Help keep soil moisture from evaporating

as rapidly

Shelterbelts Planted to provide protection to crops

and livestock Consists of trees and shrubs Height and density determine

effectiveness Reduce the effects of high wind up to 20

times the windbreak height

Conservation Tillage Conserves soil moisture Reduces surface wind speed Holds loose soil particles in place One exception-

In areas of low wind erosion danger farmers will sometimes cultivate the surface of the soil into a loose, sandy layer to conserve soil moisture

Summary* Best erosion control is to use the land according

to it capability Vegetative controls for water erosion include-

cover crops, crop rotation, strip cropping, grassed waterways

Mechanical controls for water erosion include conservation tillage, contour farming and terraces

Wind-caused erosion controls include windbreaks, shelterbelts, conservation tillage and contour farming