Sally A. Flis, Ph.D. – Feed and Crop Support Specialist, Dairy One

Following up on the theme of spring from the last blog, the calendar now says it is spring, but in most of the Northeast it has been more like winter than most of winter was this year. As the days get longer everyone is ready to get started in the next growing season, but there is only one, maybe two chances to get it right each season and then we have to wait a year to try again.  So it is imperative that we make the most of each attempt and use all the information available to make the best possible decisions. In this blog the focus is on soil temperature.

However, if crops are planted before the soil is ready – in the best case you can have slow germination and in the worst case you could have to replant. So what should the soil be like when you are ready to plant?

Soil temperature should be at or above 50°F for corn planting and 54°F for soybeans. Higher soil temperatures at planting can result in faster germination. Soil moisture content will have a large influence on the rate at which soil temperature changes. Water buffers temperature and the higher the moisture the slower temperature will change in either direction. Higher moisture levels will also have more potential for seeds to swell, not germinate, and rot.

Other factors that will influence soil temperature change:

Tillage practices: a no-till soil will warm slower than a soil that is tilled in the spring. Mixing the soil will help move water out, resulting in increased soil temperatures.

Soil Type: as we have all observed some soils hold water tighter than others. Clay soils will warm more slowly due to it’s higher moisture content and attraction to water. Conversely, soils with higher sand content will warm faster because water moves out of the soil faster.

Artificial Drainage: drainage is installed in fields to manage water content. Fields with heavier soils (more clay) and drainage will warm faster than clay field with no drainage.

sol thermometer pic

Finally, remember that soil and water temperature change more slowly than air temperature, so the best thing to do is measure soil temperature before you are ready to plant.