What are the causes of soil compaction?
Soil compaction is one of the most important factors that can affect soil health and reduce crop yields. In the early 1980s, Purdue University soil scientist Gary Steinhardt and Ohio State University Ag Engineer Randall Reeder were making farmers aware of the compaction problem and its effect on yield reduction. Compaction may be caused in many ways. We need to diagnose the reasons for compaction 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. It may also be caused by the impact of irrigation water.
• If the soil is left bare and is exposed to hard rains or irrigation water, the impact of water breaks down the larger soil aggregates and the granular structure of the soil on the surface are degraded, causing compaction.
• Surface compaction can affect water infiltration into the soil and interfere with the seed germination and seedling emergence. If the seedlings cannot break through the crust, it can lead to the reduction in plant populations and yield.
• For short term solution, the crust may be broken by light disking or other tillage tools to help the seedlings to emerge.
• To prevent crusting, we need to leave a protective layer of crop residue on the surface or cover crop and use of minimum or reduced tillage practices. The residue layer should help in absorbing the impact of rain drops before they can hit and breakdown the soil structure.
• The use of forages in crop rotation can also help in improving the granular structure of soil and reduce surface compaction from irrigation. Proper management of irrigation water to control proper infiltration is very important.
• The management practices that improve the organic matter content of the soil should aid in reducing surface compaction. Next week we will discuss various types of subsurface compaction and how to reduce them.