Does your tillage/cropping system promote good physical soil structure?

Tillage is of no benefit to the soil itself. Some do tillage to prepare a seedbed, incorporate fertilizer/manure or manage a problem like weeds or compaction. But tillage, especially extra tillage passes, can be harmful to soil structure and may result in poor crop yield from poorly functioning soils.

Chris Bandura, Conservation Cropping Outreach Specialist with UW-Extension shared the following illustration recently:

Good Structure

• Loose soil particles, greater pore space

Poor Structure

• Surface crust

• Poor rooting

• Tillage pan

• Subsoil compaction

Broader Explanation:

• Soil structure refers to the grouping and arrangement of individual soil particles (sand, silt, clay) into larger pieces called aggregates.

• Healthy soils have high aggregate stability, meaning they can maintain their structure and resist the impact of external pressures such as rainfall and compaction from equipment traffic. Powdery soil or soil with large clods are indicators of poor soil structure.

• Good soil structure allows for air and water movement within the soil via greater pore space. Better structure and more aggregation generally results in greater water infiltration rates and storage capacity.

Good soil structure will allow for root growth. Water infiltration rates and water holding capacity will be greater, providing benefits to crops during extreme wet or dry weather. 

Soils that promote root growth will help with nutrient uptake. Dr. Joel Gruver at Western Illinois University recently stated, “I think the most straight forward strategy for unlocking uptake of previously unavailable P, K and other nutrients is to increase the volume of soil favorable for healthy root growth.”

Recently there has been an emphasis on practices like cover cropping and less tillage that help preserve and improve soil structure.