I want to develop a soil fertility testing device and need an electro chemical sensor to do so. I searched the online available sensors but didn't get any source. Does anyone knows anybody in development of such sensors ?

  • 2
    I think you would be better getting this question moved to SE EE. They know more about general electronics. – Code Gorilla Aug 18 '17 at 7:14

You have pH and humidity sensors for Arduino, but "soil fertility" is an unprecise term.

If you do a web search, you will find results for a number of devices that claim to measure soil fertility. I am highly suspect of these devices. Even laboratory testing cannot tell you accurately how fertile your soils are because of the methods used. Most labs test for the presence of inorganic chemals, including nitrogen, potassium, phosphorous and an array of other nutrients plants need. What most of them do not or cannot measure is the amount of plant-available nutrients in the soil. It takes a host of soil organisms to make nutrients in the soil available to plants. If those organisms are not present or are low in numbers, it is difficult for plants to take up nutrients. Fertilizers only exacerbate the problem because they kill off soil organisms, especially mycorrhizal fungi, throwing the entire ecology of the soil out of kilter. There are a couple of laboritories out there that test for soil biology and some nutrients.

Soil is hard. There is a lot of things in soil (compactness, unwanted chemicals/elements, microbes) that can affect the fertility, even if you have the right nutrients in it.

For hydroponic (not your case), you have cheap handheld EC/TDS meters. The pH and EC of your reservoir is all you need to measure the fertility of your water solution.

Go hydro and stop worrying about your tomatoes.

  • May want to throw in that depending on environment, monitoring water temp is very important as well in a hydroponic system. – stevieb Aug 18 '17 at 12:51
  • @stevieg. If your room temperature is right, then your water temperature is OK. The only part that needs automation in hydro is maintaining water level; you can lost 1 lt/day (or more). pH and EC are relatively stable, and adding more nutrient solution usually correct the pH going high and add new nuts to the reservoir (DWC). – user31481 Aug 18 '17 at 13:01

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