Last week brought a fantastic and long-anticipated present from the Czech Republic in my mail: two heavy boxes with over a hundred TOMST TMS-4s. That name is a code for something that I would call without exaggeration a new era in microclimate monitoring.

Testing our new TMS4s in the field, before shipping them off to Scandinavia for their real duties

Faithful followers of this blog should by now know that I am a strong advocate for measuring climatic conditions right where it matters for plants and other organisms. I want us all to get away from the coarse-scaled decennial climate averages based on weather station data, as for most organisms, these climatic values are strongly decoupled from the conditions they actually experience.

I have been pushing a lot for the measurement of topsoil temperature (with our recent SoilTemp-initiative as a good example), as these temperatures are close to the core of the environment for many organisms and allow to take into account the strong mismatch between air and surface temperatures (e.g. under the snow or on the forest floor).

Yet we can – and should – do better! Soil temperature is a huge improvement over air temperature, but there is a lot more relevant parameters to measure. Our colleagues at TOMST and the Institute of Botany of the Czech Republic developed, tested and commercialized a major step forward in that regard: the TMS Temperature and Moisture Sensor. These little white mushrooms not only measure soil temperature, but also surface ànd air temperature close to the soil surface. Moreover, they measure soil moisture, a crucial driver of plant life (and soil climate). As such, the sensor simulates a small plant, measuring the main climatic conditions that plant would experience.

The TMS4, with the mushroom head to protect against the sun (left), and the soil moisture sensor (in green, on the right)

To anybody in need of accurate microclimatic conditions for organisms living close to the soil surface, I highly recommend these, especially because they sound very promising regarding battery life and memory size. And if you do buy them, consider submitting the resulting observations to our growing SoilTemp-database!

If you want to read more about these loggers, I can recommend you the new paper from Wild et al. (2019), describing them in detail. Now please excuse me, I have to go write project proposals to buy a ton more of these gems!