Comparison of Soil Temperatures in a Prairie vs. Barren Agricultural Field

 

 

 

Mary Ustymowicz

Alverno College

November 2000

BI 341

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Abstract

 

Soil Temperatures were recorded by hand thermometer and data loggers to compare soil temperature differences in a prairie and barren field. The test ran a duration of three days with temperatures taken at certain times of each day. It was found that the temperatures in the prairie, which contained groundcover, did not change as rapidly throughout the day as the barren field soil temperatures. Overall, however, the differences in temperatures were slight and considered of little significance.

 

Keywords: Soil Temperature, Groundcover, Prairie

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Introduction:

An area of land in Racine County is occupied with both an agricultural field and a prairie. The two types of areas are located adjacent to each other. They both receive relatively the same amounts of sunshine and shade. The prairie contains many types of grasses, wildflowers and weeds as groundcover. The agricultural field has been cultivated for the season so it is barren.

Since the groundcover in both areas is so different, will the soil temperature be different throughout the day? Vegetation tends to affect the variability of temperatures of the soil (Flerchinger 1997). The field has no type of plant cover so it can easily get much sunshine. The prairie soil is covered with many plants so sunshine can not penetrate the soil as readily as in the barren field. Therefore, the field soil will heat up more quickly because there is nothing to reflect the solar radiation. The prairie, on the other hand, should reflect more sun radiation and not warm up as fast (O’Connell 1999).

 

Hypothesis:

Soil in a barren area will change greater in temperature throughout the day than an area covered with vegetation.

 

 

Methods:

Two data loggers that record the temperature periodically throughout the day were buried 5 cm under the ground. One was placed in the prairie, the other in the agricultural field. The loggers were set to record approximately every 3 minutes for a duration of three days. The loggers were not touched or taken out of the ground for those three days. When the time was completed, the data was recorded onto a computer program called LogBook for Windows and all recordings were graphed.

Temperatures were also taken by hand. An alcohol thermometer was placed in each area approximately 3cm under ground. The thermometer was left alone for five minutes in each area and the temperature was recorded. Three readings were taken each time for a period of three days and the results were averaged to give a final temperature. Temperatures were taken at 7am, 1:30pm, 5pm and 9pm.

Results:

The data logger temperature readings were graphed as follows:

 

 

Field Temperatures Prairie Temperatures

The minimum field temperature was 5.38 C while the maximum was 15.83 C.

The minimum prairie temperature was 5.98 C while the maximum was 15.06C.

Looking at the two graphs, you can see that the dips in the field temperature are greater that the dips in the prairie temperature. This is also proven by the minimum and maximum temperature differences. It seems that the field tended to get slightly colder and warmer throughout the day. The prairie temperature also changed, but not as greatly.

The hand-recorded temperatures are as follows:

Prairie *C

Field *C

5pm

17.6

16.3

9pm

15.1

14.6

7am

15.1

15

1:30pm

15.1

15.9

5pm

14.6

14.4

9pm

14.1

13.6

7am

13.9

14.1

1:30pm

15.9

16.5

5pm

15.2

13.9

9pm

10.6

9.4

7am

11.1

10.4

1:30pm

13.3

14.1

5pm

13.2

13.8

9pm

11.5

10.4

A t-test for this data was done. The result was .1037. This means that the differences in temperatures of the prairie and field are not significant even though there is a slight deviation between the two areas.

 

 

Conclusion:

The hypothesis of this testing is refuted because there is not a high level of significance between the data. The temperatures in a barren field do change more throughout the day than a prairie, but only to a small extent. This points to the idea that the prairie foliage insulates the soil so it does not cool or warm as fast as an area with less. In other research, it has been shown that during summer months, prairie soil will be cooler while in the winter it will be a bit warmer (Archibold 1996). More data compared between the two areas may help to make the data collected for this experiment significant.

These temperature trends do not only occur between the prairie and field, but also in other microclimates. Canopy cover in woody areas also have lower temperatures than that of an area with no canopy cover (Breshears 1998). Also the field barren field temperatures will change when it is cultivated. For example, as the growing season corn progresses the soil temperature differences decrease (Drury 1999). Unfortunately the data for this experiment did not have a great enough difference to support these claims this for sure.

I cannot, however, determine whether the data loggers were accurate or not. Since this is my first time using such equipment, I cannot tell what is accurate. I do know that the temperatures recorded were similar to the results that I recorded by hand. Therefore I can be somewhat sure of my results.

The effects of the outside temperatures were not considered. I would assume that if there were a great fluctuation in outside temperature, the field temperature would fluctuate greater while the prairie temperature would not be as different. The outside temperatures while doing this experiment were not very different from day and night ranging between 45-60 C each day. It would be interesting to see the affects of temperature on the two areas in the summer when the temperatures throughout the day rise and fall more. I would also have liked to log more days with the data loggers, but because of time constraints, it was not possible.

 

 

References:

Archibold,O., Ripley, E. Bretell, D. 1996. Comparison of Microclimates of a Small Aspen Grove and Adjacent Prairie in Saskatchewan. The American Midland Naturalist v136 p. 248-261.

Breshears, D., Heil,c., Nyhan,J. 1998. Effects of Woody Plants on Microclimate in a Semiarid Woodland. International Journal of Plant Sciences v159, p. 1010-1017.

Drury, C., Tan, C., Welacky, T., Oloya, T.,Hammill, A., Weaver,S. 1999. Red Clover and Tillage Influence on Soil Temperature, Water Content and Corn Emergence. Agronomy Journal v91 p. 101-108.

Flerchinger, G., Pierson, F. 1997. Modelling Plant Canopy Effects on Variability of soil Temperature and water. Journal of Arid Environments v35 p. 641-653.

O’Connell, N. 1999. Cover Crops, Mulch and Night Temperatures in Citrus. California Agriculture v53 p.37-40.