Probably 20 years behind others on most things - e.g. cannabis growers etc have long understood the deficiency symptoms associated to the various nutrients but some interesting findings never the less re point at which a deficiency becomes apparent and other.
https://www.mdpi.com/2076-3417/9/20/4432/htm
https://www.mdpi.com/2076-3417/9/20/4432/htm