Iron deficiency in soya beans as well as the soil itself, soil pH, soil moisture, structure, compaction, the hybrid and timing," says Vyn. He emphasizes the need for more research to better understand these factors, in particular timing and placement of application on fields where micronutrient deficiencies have been observed.
" We are trying to drive home how much micronutrient uptake takes place during grain fill," says Vyn. " We found that 50 % of iron and 30 % of manganese enters the plant after flowering. Up to 55 % of zinc found in the maize plant at maturity enters the plant after silking. However, optimum timing of micronutrient uptake, in terms of high-yield component formation, was not tested in that study of different hybrids, N rates and plant populations."
Foliar micronutrients
For Charles Schulze, who farms near Waynesfield, Ohio, timing is key. For the past 15 years, he has relied on in-furrow liquid starter to ensure micronutrient availability to boost the plant and root system. About 10 years ago, he added a foliar micronutrient application in late June to maize and soya beans and a late-July application to soybeans. Combined with a basic fertility program and side dressing nitrogen, he claims a 390-470 kg / Ha increased yield in maize and a 250-370Kg / Ha yield increase in soya beans from the comprehensive program.
" I believe spoon-feeding my crops has to be better than all at once," says Schulze. " Once I saw the plant health and yield benefits from the starter and then the foliar, I ramped up the program accordingly."
Schulze broadcasts phosphorus and potassium in front of the maize planter, lays down a 06- 24-06 liquid starter with manganese, boron and zinc and other additives in-furrow along with about 20 % of his nitrogen as 10-34-0 dry in a 2” x2” alongside the row. That is followed by anhydrous ammonia sidedressed for the bulk of his N and the foliar applications.
FARMERS GAZETTE November 2015 35