John Heard, Soil Fertility Specialist with Manitoba Agriculture, says the condition typically appears on crops planted in lighter, sandier soil which naturally have lower potassium levels. He adds soil compaction, any condition that limits rooting - such as insect feeding or herbicide residues, and zero-tilling into dense soil also contribute to the risk. Environmental factors play a role as well.
"This year has weathered cold, dry soils and those conditions slow or reduce the diffusion of potassium to the root," explained Heard.
In addition, Heard speculates that there's a general lack of awareness among growers recognizing the potash recommendations for corn. He notes Manitoba recommendations have been very aggressive for years, with a critical soil level of 200 parts per million.
Heard adds placement is also key, noting broadcast potash is not as available to corn and therefore two times as much is required than the response offered by banded 'K'.Click here to see more...