SCOTT, Sask. – Post-emergent fertilizer applications allow farmers to
adjust fertility rates part way through the growing season. If it’s
dry, nitrogen costs are kept down. If there’s extra moisture and
excellent growing conditions, an extra shot of nitrogen might boost
profit levels. But there are more questions than answers regarding the
process.
Stu Brandt, a crop management researcher at the Ag Canada research farm
at Scott, Sask., is trying to answer some of those questions.
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Together with researchers at Indian Head, Sask., he’s comparing surface
dribble banding to coulter banding liquid fertilizer on wheat and
canola.
Researchers are trying to answer the following questions:
- Does soil banding improve responses over surface banding?
- Does adding ammonium thiosulfate improve nitrogen use of surface
dribble bands?
- How late can you apply fertilizer before reducing yields?
- Do later soil banding applications improve crop response more,
compared to later surface banding?
Brandt cautioned that they have only one year of results so far and
both locations had well below normal growing season moisture.
Low moisture conditions mean the amount of nitrogen required to
optimize yield is lower. But he said some trends are emerging.
Regardless of how nitrogen was applied, it increased the yield of both
crops at both locations. In-crop surface dribble and coulter banding
provided similar yields to fertilizer banded when seeding.
Adding ammonium thiosulfate (ATS) to urea ammonium nitrate (UAN) made
no difference in nitrogen use from surface band applications. With or
without ATS, the surface dribble banded UAN performed the same.
Results summarized
While plant densities tended to decline after nitrogen was surface
dribble banded or coulter banded – to the tune of 12 to 23 percent –
Brandt said plant stands were adequate and he didn’t feel yields were
compromised.
He did say in-crop applications appeared to delay maturity compared to
applying all nitrogen at seeding, but he wasn’t sure if it was from
reduced plant stands, nitrogen timing or some other factors. Protein
responses were inconsistent.
Brandt used an angled coulter disc to apply the in-crop fertilizer
application, while the surface bands were applied with the same
implement pulled out of the ground.
He said the coulter tends to cut the canola leaves off more than the
cereal leaves when banding the fertilizer into the ground. He also said
that surface applied liquid fertilizer rolled off the cereal crop
leaves more, while some of the canola leaves collected fertilizer and
were burned. But these problems were more than offset by the benefits
of the extra fertilizer.
