In the permanent section about professional devices, we will tell you about the AM Probe Thermometer-6

The AM-6 probe thermometer is a glass thermometer in a special frame with a handle made of a heat-insulating composite material and a cone-shaped metal tip.
The principle of operation of the probe thermometer is based on the ability of a metal tip with copper or brass sawdust to provide thermal contact with the soil and heat transfer from it to the receiving part of the thermometer (toluene tank).
On the one hand, the frame has a longitudinal cutout, closed with organic glass for taking readings from the thermometer scale, and on the other side of the frame there are divisions after 1 cm, which serve to determine the depth of immersion of the thermometer-probe in the soil.
The probe thermometer is used on the agrometeorological network to monitor the temperature of the arable soil layer in the spring period, starting from the moment of drying of the soil. The temperature is measured at a depth of 5 cm. and 10 cm., two repetitions at each depth. Observations in the fields continue until the appearance of mass shoots of thermophilic crops (corn, cotton, sunflower, rice, buckwheat, millet, as well as potatoes, sugar beet, etc.). The thermometer-probe is also used in conducting route surveys of agricultural crops.