Understanding Soil Temperature Measurement Techniques and Their Importance
This article explores the significance of studying soil temperature and the methods used to measure it accurately. A soil thermometer measures temperatures at 5 and 10 cm depths, and proper calibration is essential for reliable readings. The calibration process is detailed, including using an ice-water bath to ensure accuracy. Furthermore, the article emphasizes the importance of regular soil temperature measurements, suggesting a weekly or daily schedule to monitor changes, particularly in relation to soil moisture data. Finally, the significance of soil moisture in understanding the Earth's water cycle is discussed.
Understanding Soil Temperature Measurement Techniques and Their Importance
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Presentation Transcript
Soil Thermometer • Used to take temperatures at 5 and 10 cm depths PVC Spacer PVC Spacer
Calibrating the Soil Thermometer Basically, we compare the soil thermometer to a calibration thermometer, and adjust the soil thermometer. First, we need to check the calibration thermometer!! …by dipping it in an ice bath.
Checking Calibration Thermometer • Submerge thermometer in ice-water bath • Let sit for 10-15 minutes, stirring thermometer occasionally • Read the thermometer. If it reads between -0.5° C and +0.5° C, the thermometer is fine. • If the thermometer reads greater than +0.5° C, check to make sure that there is more ice than water in your ice-water bath. • If the thermometer reads less than -0.5° C, check to make sure that there is no salt in your ice-water bath.
Soil Thermometer Calibration • Add the soil thermometer to the ice bath • Wait 2 minutes • Read both Soil Thermometer and calibration thermometer. • If they agree to within ±2° C, the soil thermometer is ready to use. • If not adjust the soil thermometer, using a wrench, until it reads with ±2° C of the calibration thermometer
When to Do the Soil Temperature Measurements • Soil temperature is a weekly measurement, but you can do it daily. • Try to do the measurement at about the same time of day • Take data near the atmosphere station or near the soil moisture site • Also measure soil temperature measurement whenever a soil moisture data are taken • Seasonally (4 times a year), measure soil temperature every few hours during the day for 2 consecutive days • provides a diurnal reading of soil temperature change • diurnal sampling in March, June, Sept. and Dec. are preferred
Soil Moisture • Why is it important to take soil moisture measurements?
Scientists want data for: ·Help track the water cycle in the Earth system • ·Help determine the times of plant sprouting and growth • ·Help scientists improve weather and climate prediction • ·Help understand the potential for decomposition and weathering of soil • ·Compare with existing models and data sets for validation and for local detail
Where To Perform the Gravimetric Soil Moisture Investigation
Drying Your Soils with a Microwave 1. Weigh your sample(s) 2. Dry on high power for 5 minutes 3. Weigh again 4. Dry on high power for 5 minutes 5. Weigh again 6. Repeat until successive weights are within .2 g of each other Multiple Samples Can Be Placed in the Microwave to Save Time *The Soil Drying Oven is the Preferred Method
Frequency of Measurement • GLOBE Soil Moisture Campaign • At least one triplicate soil moisture measurement during the first 2 weeks of October (World Space Week and Earth Science Week) • 4th week of April (Earth Day Week) • At least 12 regularly spaced intervals • Encouraged to sample the wet, intermediate and dry times surrounding major wet periods
Soil Moisture Soil Water Content Formula
