What sort of equipment would one need to ensure that plant soil contains the right concentration of the 13 mineral nutrients necessary for plant growth? Specifically, can this be measured in real-time without involving sending samples to a lab?
As far I understand, it's vital that all the following elements are present: nitrogen, phosphorus, potassium, calcium, magnesium, sulfur, boron, copper, iron, chloride, manganese, molybdenum and zinc.
It seems like simply measuring pH gives only a rough estimate and is not a very precise indicator of the various element levels.