Hi Mads,

Have you had a soil test to see where there may be severe mineral defencies in your soil? Here in the US we have soil tests that will use mild acids to see what minerals the plants have available to them in the soil. We can also get a mining assay soil test which will tell you exactly what minerals you have in your soil. This can be useful as a long term goal for knowing what soil biology can access. For example if your mining assay shows you have no boron or very low potassium, you will know that those minerals will have to be brought into your farm. If the mining assay shows your soil has good boron and adequate potassium, but a mild acid or sap test shows your plants are not able to use it, then you know you have some work to get your soil biology up.

In terms of using AEA products without sap anaylyis, it can be done. I grow 40 different types of vegetables on 14 acres of cropland and do not sap test all my crops. I do have to say, that I will sap test our more valuable crops. Which for me is a single crop that brings in 10k+ in revenue for the farm. If a few crops are sap tested several years in a row, then you will generally see a pattern of imbalances and will not need to pull sap tests as often in my opinion unless you are seeing a new prolbem. In my experience a fall and or spring soil primer, seed innoculant, holocal(either fertigated or foliar), and micro pak has gotten me better quality produce across the board. If you are having a specific problem and the crop revenue can justify the cost a sap analyses will be very useful. I would say some of the most importants aspects of applying nutrients would be to avoid excesses. It is amazing how often a mineral defiency is actually caused by an excess of another mineral. Water quality for foliars if also very improtant. Water hardness over 10 grains will impede the effectiveness of a foliar application.

I hope that helps!