Table of Contents

Using Conservation Structures to Control Erosion

An integrated system of reduced tillage practices and conservation structures is needed for successful soil and water conservation. Crop residue on the soil surface reduces the effect of rainfall intensity and helps to keep sediments in place, especially on flat fields. However, conservation structures such as terraces, grass waterways, and conservation buffers are needed to reduce the velocity of water and sediment transport off fields.

Conservation tillage systems need to be combined with crop rotations and conservation structures to control surface runoff and soil erosion effectively on many sloping south-central Minnesota fields. In a corn-soybean rotation, soil erosion can often be controlled by conservation tillage in combination with grass waterways or terraces. Even if corn is planted without tillage into soybean stubble, grass waterways or terraces are often needed to minimize erosion on steeper or longer sloping fields.

Grass buffers at the edge of a field, drainage ditch, or stream should be installed to supplement conservation tillage practices in the field, and not be considered as a replacement for conservation practices. In fact, field buffers are effective mainly against sheet and rill erosion, and can be easily breached by gully erosion or channeled flow that is the result of insufficient erosion control on the uplands.

Conservation plans illustrate how combinations of management practices and conservation structures can successfully control erosion. Individual farms may need site-specific designs that differ from typical systems. Farmers can contact their local Soil and Water Conservation District or Natural Resources Conservation Service office for help in determining which combination of conservation tillage, crop rotation, and conservation structures is best for their farm.