Even if enough Fe is in the soil, deficiency can occur under the following conditions: poorly drained soil, high Ca, high Mn, high pH, high P, high heavy metals, oxygen deficiency. Deficiency symptoms General: Yellow or white areas on youngest leaves. Older leaves remain green.
The Bt corn can produce unpredictable toxins and allergens into food plants and therefore into the final product. Also the Bt corn can be considered unstable as the number of copies of an inserted gene changes through later generations of the Bt corn. The low tillage is also a prime spot for a monoculture in the fields. A monoculture is where all of the crops are the same, so with this it is a perfect situation for weeds.
While not from the official/government source, there are reports that some Amish use GMO seeds â BT corn (From: BBC) and nicotine-free tobacco (From: Wired). Whatâs interesting, this BBC video actually shows a horse drawn carriage with a chemical cistern mounted on the top, used to spray chemicals on the fields.