I bought and used a soil testing kit where pellets of unknown chemical were disolved in a water solution taken from a soil sample. The resulting color matching gives information as to whether the soil is deficient in nitrogen, potassium, and phosphorous. I suspect the color indicates the amount of the nitrogen, potassium,or phosphorus ion.
Can someone tell me where I can get information as to what the chemical interaction is and what is the chemical in the pellets.
Thanks