Photo Credit: Claire Coombs, Penn State Extension.
During planting season, it is difficult to try and fit everything in, especially when trying to dodge rainstorms that seem to be common this spring. With the pressure to get all fields planted, it can be tempting to go into a field that is less than ideal for planting. If the soils are too wet, they can be easily compacted and there will be an increased risk for sidewall compaction.
Sidewall compaction can refer to any and all soil compaction and/or soil smearing in and around the seed furrow. It is often caused by planting when too wet, planting too shallow and setting too much down pressure on the gauge wheels and closing wheels. Sidewall compaction can be especially damaging if a dry spell occurs after planting, resulting in an open seed well. It is critical to assess if the soil is dry enough for planting and this can easily be done in the field. The following are two methods to assess soil moisture by hand:
- Collect soil from the top 2-3 inches in your hand and make a small ball (slightly larger than a golf ball) in your hand. Throw the ball in the air as if you were throwing a baseball. If the ball of soil reaches the ground intact, it is probably too wet to plant. If the ball breaks apart in mid-air, it may be dry enough to plant
- Again, collect soil from the top 2-3 inches and form a ball in your hand. Squeeze the soil between your thumb and forefinger to form a ribbon of soil. If the soil creates a ribbon longer than 3 inches before breaking, it is probably too wet to plant.
While soil moisture will be critical to preventing sidewall compaction, it is also important to ensure the seed furrow is closed while using minimal down pressure in the closing wheels. With too shallow of planting, there is an increased risk of the closing wheels not functioning correctly, which can result in an open seed furrow.
With a wet spring it can be difficult to wait for ideal planting conditions but it is important to ensure the soil is not too wet. Sidewall compaction cannot be fixed once it occurs and can have detrimental effects on crop performance and yield. Consequences of sidewall compaction include reduced germination, poor stands, uneven emergence and growth, and restricted root growth. All these consequences can have a negative effect on yield when harvesting in the fall. It may be hard to patiently wait while the field dries out, but to ensure the highest yields possible in the fall we need to wait a few more days to reap the rewards in several months.
For more information on all types of compaction, see our Avoiding Soil Compaction fact sheet.