Doing some more thinking about this issue of holding capacity. It appears to me that minerals such as zinc, copper, phosphorus and possibly iron and manganese easily stick around in the soil profile independent of the sand, silt, clay, organic matter charge. I’ve seen sandy soils with low CEC that easily hold these minerals. This seems to suggest to me that holding capacity has other principles besides the negative charge in soil. Minerals can build up in soil for different reasons than simply binding to a soil particle charge.

Maybe calcium and perhaps magnesium to an extent can build up in soil for other reasons such as the examples above. This would give me some insight on how I can have different areas of my property that have the same sand base with 6-7% organic matter with a TEC of 7 while other areas are at 13-15. Both the 7 and 15 are weaker at holding potassium it seems. Time will tell with experimentation if K buildup is more difficult in one or the other. I’m only just now getting the opportunity to work on some neglected areas of my property. However this all just continues to suggest to me how flawed CEC seems to be. It seems to me that holding capacity should be explained differently than it often currently is. I also may simply need more education to fix any misunderstandings I may have. I’m just reporting what I see on my property.