Reducing soil compaction in 2020

April 3, 2020

Soils have gone through a lot since the fall of 2018, and that has caused a lot of compaction.

“I have seen corn fields during July and August that showed the effects of soil compaction which was caused during the spring. It is one of the most important factors that can affect soil health and reduce yields,” said Dave Nanda, Ph.D., SGD director of genetics. “If your goal is to raise your yields, reducing compaction is one of the most important factors.”

According to Nanda, soil compaction can be caused in many ways and the reasons for compaction should be diagnosed on a field by field basis before corrective measures can be taken.

Surface compaction can occur from the impact of rain drops or in the form of crusting due to excessive rains and ponding. If soil is left bare and is then exposed to hard rains or irrigation water, the impact of the water breaks down larger soil aggregates and the granular structure of the soil on the surface is degraded, causing compaction. This can affect water infiltration into the soil and interfere with seed germination and seedling emergence. If seedlings cannot break through the crust, it can lead to reduction in plant populations and yield. For short term solutions, the crust may be broken by light disking, or other tillage tools, to help emergence of the seedlings.

To prevent crusting, leave a protective layer of crop residue on the surface or cover crop and reduce tillage practices. The residue layer should help in absorbing the impact of rain drops before they can hit and break down the soil structure.

Using forages in crop rotation and managing irrigation to control infiltration can also help improve granular structure of soil and reduce surface compaction.

Compaction can also be caused by wheel traffic and equipment, increasing with the amount of soil moisture.

“We all know that soil compaction caused by tractors, manure spreaders, carts, combines and other farm equipment cannot be completely eliminated. However, we can minimize it as much as possible and then take long-term agronomic measures to reverse it, ” said Nanda. “ Using a soil penetrometer or walking a field with an expert, like an SGD seedsman, can help determine if you have a compaction problem.”

Rotation of fibrous roots with deep-rooted crops can also help in reducing compaction.

“I strongly recommend the use of cover crops,” advised Nanda. “They will improve the organic matter content of your soils, reduce compaction, improve soil health and increase yields.”