Soil and Water Conservation

Tillage has four purposes:

Incorporation of plant residues, fertilizers, etc.
Seedbed preparation
Weed control
Soil and water conservation

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Primary Tillage: Incorporation

Secondary Tillage:
Weed Control

Secondary Tillage:
Seedbed Preparation

Soil and Water Conservation

Planters and Drills

Emergency tillage for wind erosion control A smooth soil surface is more subject to blow during wind erosion. Emergency tillage is done to roughen the soil surface which will slow the wind velocity at the soil surface and thereby reduce erosion. In many ways the battle has already been lost if emergency tillage is required. Residue or growing plants on the surface are effective deterrents to erosion.

Wind erosion limits visibility.	Wind erosion can begin with windspeeds as low as 13 mph.	Downdrafts before thunderstorms often generate wind erosion.	Sandy soils are particularly susceptible to wind erosion

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Sandfighters - light equipment that can be quickly pulled across the soil surface. These are used primarily on sandy soils. Sandy soils are most susceptible to wind erosion, especially in the spring when residue cover is low, and sometimes soon after a thunderstorm that destroys surface structure.

The photos at right show different sandfighter designs.

The photos below show the surface condition after using a sandfighter. The surface was smooth before cultivation. Notice plants are neither disturbed nor harmed.

close-up, soil roughened with sandfighter

sandfighter, alternate design

Rotary Hoe - also roughens surface limits wind erosion susceptibility

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Tillage to promote water conservation and improving water storage efficiency

Furrow dyker - These implements are often attached behind cultivators, planters, and other implements
They make small dams and reservoirs that limit runoff and increase soil water storage.
furrow dyker in use in field furrow dyker design

3-fin, furrow dyker design furrow-dyked field after rain

probe shows infiltration in dyked row probe shows water retention in undyked furrow

The effect of the dam can be seen in the comparison of the probe depth in these two slides. Only about 30 cm of the 150 cm probe remains above the ground in the dyked row. In the undyked row, the about 90 cm of the 150 cm probe remains above ground. The probe can be inserted to wet soil (soil that contains water that is available for plants) and can't be inserted into dry soil. For a wide range of soils there are about 30 to 50 mm of plant available water for every 30 cm the probe can be inserted into the ground.

Residues on the surface decrease evaporation and slow water loss from the surface.
Soils shaded by crop canopies or covered by residues lose less water.
canopy and residues shade part of surface

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Water erosion

Water erosion from a land surface occurs in four basic forms: sheet, rill, gully, and streambank. Sheet erosion is imperceptible, as a single layer of soil particles is removed uniformly from a soil surface. Rill erosion is the first observable water erosion process to the human eye, as the runoff waters concentrate and begin to flow in small channels. Three examples of these channels are shown below. The rills on the left are the most advanced. If they were left uncontrolled, or continued unabated, they could develop into gullies. Gullies can not be crossed by tillage implements, and so require special management. Streambank erosion is a river phenomenon, and not directly related to runoff from the soil surface.

deepening rills after runoff event small rill after runoff event uneven surface after runoff event

Systems that promote soil conservation and deal with runoff

Terraces - Terraces are used to slow runoff from the landscape, and redirect it toward a discharge point. Terraces often discharge into grassed waterways.

The detailed terracing in the aerial view are seen better in the larger photo.
Japanese terraces aerial view of U.S. Rolling Plains terraces

Grassed waterways - These waterways are used to convey water out of a field while minimizing soil detachment.

Contour Tillage - Rows are constructed along contour lines (equal elevation). The manager of this field has incoporated many good management practices: terraces, coutour tillage, and furrow dykes in alternate rows.
contour tillage on terraces with furrow dykes

Dr. Dirt's Homepage Tillage Homepage Primary Tillage: Incorporation Secondary Tillage:
Weed Control Secondary Tillage:
Seedbed Preparation Soil and Water Conservation Planters and Drills

Updated 06-29-2005. Copyright 2005. Clay Robinson, Ph.D., as to all resources: Materials may not be reproduced without Dr. Robinson's written consent. Students are prohibited from selling (or being paid for taking) notes or webpages during this course to or by any person or commercial firm without the express written permission of the developer of these pages.
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Furrow dyker - These implements are often attached behind cultivators, planters, and other implements They make small dams and reservoirs that limit runoff and increase soil water storage.


The effect of the dam can be seen in the comparison of the probe depth in these two slides. Only about 30 cm of the 150 cm probe remains above the ground in the dyked row.	In the undyked row, the about 90 cm of the 150 cm probe remains above ground. The probe can be inserted to wet soil (soil that contains water that is available for plants) and can't be inserted into dry soil. For a wide range of soils there are about 30 to 50 mm of plant available water for every 30 cm the probe can be inserted into the ground.
Residues on the surface decrease evaporation and slow water loss from the surface. Soils shaded by crop canopies or covered by residues lose less water.

Water erosion from a land surface occurs in four basic forms: sheet, rill, gully, and streambank. Sheet erosion is imperceptible, as a single layer of soil particles is removed uniformly from a soil surface. Rill erosion is the first observable water erosion process to the human eye, as the runoff waters concentrate and begin to flow in small channels. Three examples of these channels are shown below. The rills on the left are the most advanced. If they were left uncontrolled, or continued unabated, they could develop into gullies. Gullies can not be crossed by tillage implements, and so require special management. Streambank erosion is a river phenomenon, and not directly related to runoff from the soil surface.

Terraces - Terraces are used to slow runoff from the landscape, and redirect it toward a discharge point. Terraces often discharge into grassed waterways. The detailed terracing in the aerial view are seen better in the larger photo.
Grassed waterways - These waterways are used to convey water out of a field while minimizing soil detachment.
Contour Tillage - Rows are constructed along contour lines (equal elevation). The manager of this field has incoporated many good management practices: terraces, coutour tillage, and furrow dykes in alternate rows.