What probe to use to test soil nutrients


I have created a Lora node and connected to TTN. I am able to read humidity and temperature and all seems nice for now. For the end product:

I am planning to install probes in agricultural fields to measure moisture, ph, temperature and humidity. For temperature and humidity, I have DHT11 sensor. However, for checking moisture and ph value of soil, I am not sure what material to use to probe the soil. Attached an image of a probe available online. probe probe

Someone who is aware of soil testing, can you please confirm the type of metal used to test ph and moisture. Also, as per the image, there is only one metal rod. How would it and what would it test? Resistivity, or capacitivity?


Have you asked the manufacturer/supplier? :thinking:

These are available in China and on Aliexpress. I sent them about electrodes and they replied saying that they are ready to source upto 1000 units per day. Not sure they would tell about electrodes. Written to them again about the electrodes used.

For this kind of measurements I would use more “professional” sensors, not the DHT 11 and not this kind of soil moisture sensor. https://dl.sciencesocieties.org/publications/vzj/abstracts/12/2/vzj2012.0160 or https://www.mdpi.com/1424-8220/11/1/1192/htm. success.

Thanks for the info. DHT11 is just for testing and will replace with a better sensor. Regarding the links you have suggested, the second link does not provide any info on probes or further details. Reading the first paper…

How are things going for you? I worked with the stevens hydraprobe, but there are more soil probes ( Spectrum, etc).