| agger802 - 12/8/2011 07:29 Here are the negitive consequences in an extreme situation below. Story: We ripped this farm to china with a huge parabolic ripper fall of 07. When I planted corn the next spring, I got root growth like I've never had before. Went to check on the corn one day and saw huge areas with plants like below. I sent plants off to the MU plant diagnostic lab and ran tissue analyses. Conclusion.......corn plants had extremely low levels of phosphorus and zinc. Iron levels were so high that MU considered them toxic to the plant. Hypothesis is that the corn roots grew into the acidic subsoil (got rid of compaction) and was able to take up excessive amounts of highly soluble iron. This caused the aforementioned nutrient defiencies in a soil that was already low in phosphate and zinc (Mexico silty clay loam). FYI, measured root growth at the stage below was over 2 feet. That is V6 corn even it doesn't look like it due to the stacked nodes caused by the nutrient deficiencies. In 2010, I had corn there again and banded phosphate and zinc in furrow and 2x2 and had very few issues. Still saw a few plants here and there with similar syptoms, but nothing severe. Plan to strip till in phosphate and zinc sulfate this spring along with the liquid starter system. Extremely interesting! -- but I'm not so sure about the conclusion of Zn def causing the symptoms -- Zn def would cause the midrib to die fairly early on, in addition to long lesions / dead areas alongside it (and, in general, the dead patterns aren't quite the right look for Zn def). However, extreme P def would look something like this. Might be some Mn def also. Usually the toxicity of one metal (Fe, for instance) is a result of interfering with the usage of other minerals in the tissue. |
what problems can high Fe levels in the soil create?
