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Little River, TX | I had much the same situation with alfalfa as Guest. My friendly Texas A & M U Soils Lab insisted I had a Very High level of potash. I also pull tissue samples and knew better.
After a number of years of frustration, I found that as the soil becomes more of a clay the soil test must be higher for the plants to take up adequate amounts of potassium, CEC is supposed to be a function of clay and organic matter. In theory we want our soil to test between CEC X 8.5 and CEC X 10. As long as I do that my alfalfa finds enough potash to survive our summer droughts.
Something else, might be just coincidental or it may be causative but I find a better response to potash when I also include some manganese. | |
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Potassium deficient soybeans
