Past IEM Features tagged: soiltemp

List all tags


Quickly Warming

27 Apr 2018 05:32 AM
The weather has been nearly perfect this week for most of Iowa with warmer air temperatures and sunshine helping to warm and dry soils allowing for spring planting to commence. The featured chart displays the daily range of four inch depth soil temperatures near Kanawha (north-central Iowa). The chart nicely depicts the story of this April. The days with no change in temperature at about 32F are those with snow cover! Once the snow cover goes away, the soil temperatures start to show life. The data for this site would indicate it only took about three days after the snow cover left for soil temperatures to exceed the magical 50 degree threshold.

Voting:
Good: 9
Bad: 2
Abstain: 1

Tags:   soiltemp  


How to Warm the Soil

18 Apr 2018 05:34 AM
Today's chart is a bit of a deep dive into drivers for changes in soil temperature. A big current weather story is the cold soil temperatures statewide which are preventing crop planting progress. The featured chart attempts to look into what it takes to produce warmer soil temperatures, in particular four inch depth soil temperatures based on period of record data from the Ames ISU AgClimate weather station during the month of April. In focus is what may drive the day to day warming or cooling of soil temperatures. The top two panels present the relationship between the day to day change in air temperature and solar radiation with the response in day to day soil temperature. The bottom two panels look more into the absolute relationship between these three parameters. One may suggest that simply having sunny days are sufficient to increase soil temperatures. While the bottom left panel does show a positive relationship (increasing radiation increases the day to day temperature change), the correlation is a bit low and would indicate other factors are at play. The upper left plot shows a stronger relationship between day to day changes in air and soil temperatures, but this relationship is physically complex via the surface energy budget. Energy will flow from warmer soils to the air and from warmer air to the soil. During the spring time, a major source of warm air is from wind transporting warmer air into the state and from daytime mixing of warmer air aloft down to the surface. The moral of the story is that these plots seem to indicate that air temperatures are more important of a driver of soil temperatures than solar input. One could think of it this way, we just had our coldest 1-15 April period on record for air temperatures not wholly due to a lack of sunshine, but from dominant cold air masses being transported into the state. Of course, it also does not help to have snow covering the ground which will be added to today, sigh!

Voting:
Good: 10
Bad: 1

Tags:   soiltemp  

Back below 50

21 Apr 2015 05:42 AM
50 degrees is an important threshold for soil temperatures when it comes to planting corn in Iowa. The featured chart displays the daily four inch depth temperature range from the Ames Ag Farm site. The warm weather last week has given way to much cooler temperatures this week and soil temperatures have dipped back below 50 degrees. The forecast for this week keeps high air temperatures in the 50s with cool overnight lows, so soil temperatures will not warm in this environment.

Voting:
Good: 10
Bad: 4
Abstain: 2

Tags:   soiltemp  

Getting the Frost Out

26 Mar 2015 05:42 AM
The featured chart displays time series of soil temperature observations from the Muscatine ISU Soil Moisture site since March 1. The chart is an awesome illustration of how the frost leaves the ground. Prior to March 7th, the four, twelve, and 24 inch readings were all below freezing. The frost had not made it to the 50 inch depth. As the soil layers warmed and reached freezing, it took a bit of time to punch through the freezing point level. This is due to processes that take extra amounts of heat to convert the frozen water in the soil to liquid. The four inch punched through first and then twelve and then 24. The chart shows that this process took eight days to reach 24 inches. Eventually the warming reached 50 inches and its temperature slowly started to rise as well.

Voting:
Good: 18
Bad: 12
Abstain: 8

Tags:   soiltemp  

Regaining 50

06 May 2014 05:37 AM
The past few days of sunshine and warmer temperatures have helped warm soil temperatures back above the critical 50 degree level. The featured chart presents a time series of four inch depth soil temperatures for each of the past 26 years with a simple average plotted in black. 50 degrees in an important threshold for crop growth and you can see that the further we get into May, the much less likely it is to breach this level to the downside. Wet soils are the current limiting factor for crop planting progress this spring and rainfall is in the forecast with the best chance on Thursday.

Voting:
Good: 19
Bad: 4
Abstain: 3

Tags:   soiltemp  


Soil Temps are Struggling

04 Apr 2013 05:44 AM
Our lack of really warm days and snows in March have not helped soil temperatures much as shown by the featured chart. The exact opposite was true in 2012 and the response was to have some of the warmest soil temperatures recorded since 1988 by mid March. Eventually, climatology will win this battle and soil temperatures will warm enough to permit gardens to be planted and agricultural crops to go in. Warmer temperatures for the rest of this week will help as well.

Voting:
Good: 22
Bad: 4

Tags:   soiltemp  


Hot soils

06 Jul 2012 05:52 AM
Our recent stretch of sunny days, hot temperatures, and mostly dry conditions have elevated soil temperatures to some of the warmest recorded by the ISU AgClimate network. The featured chart presents the warmest average daily four inch depth soil temperature for the Ames site since its installation back in 1986. It is possible that temperatures will warm even more as we are not yet to their climatological peak in August.

Voting:
Good: 57
Bad: 7

Tags:   soiltemp  


Plant Corn in March?

19 Mar 2012 07:25 AM
Our recent stretch of record heat and limited precipitation has warmed our soil temperatures to levels one would expect in late April. The featured chart presents daily time series of four inch depth soil temperatures for each year since 1988. The red line represents this year and shows the unprecedented current soil temperature levels. Sustained temperatures above 50 degrees Fahrenheit are typically considered necessary to plant corn, so our current average temperatures well north of 60 degrees would be sufficient. The problem is that the calendar still says the middle of March and there is plenty of time for cold weather to return or even snow!

Voting:
Good: 32
Bad: 4

Tags:   soiltemp