Thank you very much for all the answers!

This soil hasn’t seen fertilizer since 6 years except for 2 applications of very mature green waste compost with 3600lb per acre. Anecdotally I know that there has been and still is regular NPK fertilizer utilization in our region. The amount of application was calculated only in regards of N and what came by as P and K was neglected. Virgin soil close to our fields has the same structure. I guess it is also a soil naturally high in K .

Naturally we don’t have to irrigate since we have around 27,5 to 31,5 inches of rainfall every year. There haven’t been any foliar applications of N,P,K or trace minerals either.

Would it be reasonable to increase the Mg levels in the soil so as to replace some of the K? I could use a product which is a combination of MgO/SO3 which would also bring sulfur to the soil. Plus I would add Boron to bring the levels up to 3-4ppm. How much B lb/acre should I apply per year to gradually build up to 4ppm?

Thanks Adam for your interpretation of the Sap Analysis I appreciate it a lot. I already stopped any N,P,K applications. My plan is to apply B,Ca,Si as a foliar for the first 2-3 sprays till the 6 leaf stage of the plant. For the Si I use a fermented Horsetail decoction. What is a good source for chelated Ca? Are there plant based sources for B and Ca?

After 6 leaf stage which I perceive as a critical point of influence I want to support the photosynthesis of the plant with a foliar spray. I hope with a better photosynthesis I’ll get more root activity which will also improve Ca,B,Si uptake. Elements I want to support are Fe,Mn and Mg maybe Mo? but I am still searching for a good product. Is there a way to make a natural photosynthesis supporter by fermenting plants?

I don’t know what the lab is using as extraction methods for the base cations. I guess it is a very standard Albrecht analysis. What would be a recommended extraction method?

Dormant sprays are sprays that are applied on a regular basis? Since we are working organic we have a regular application of Cu of 0,09 to 0,18lbs per acre and S of 3,2lbs per acre.

Regards Johannes