May 2, 2013

No two years are the same and soil temperature data from the past couple years is a good example. I charted the April soil temperature at the 4-inch depth for York (see Figure 1). As you look at the chart, the long-term (1996 – present) soil temperature average at 4 inches steadily increases from 47.2°F on April 1 to 55.3°F on April 30. I wish that would always be the case, but if you look at the 2012 data, soil temperatures on average were 6.6°F higher compared to normal and in 2013 they are averaging 5.2°F below normal.

Jed Erickson from Pioneer Hi-Bred in York has been taking soil temperature readings at the 4-inch depth daily at 7:15 a.m. in three fields: conventional tilled corn, soybean stubble, and no-till corn residue. (The temperature at 7:15 a.m. should be the low temperature for the day.) These soil temperatures were averaged and are also plotted in Figure 1. They averaged about 6.5°F less than the daily averages for 2013.

It’s also interesting to note that there has been less than one degree difference in temperature among the 7:15 a.m. readings at the three fields (Figure 2). The soybean residue field was the warmest and the no-till field the coldest.

For more information see daily soil temperature updates in CropWatch, reported graphically in maps as well as in tables for locations across the state. The table includes a seven-day average as well as the average soil temperature for the previous day.

Gary Zoubek
Extension Educator, York County