Manitoba Agriculture says repeated rains and warm soils have led to widespread nitrogen fertilizer losses.
"Coming out of last year, a lot of the droughted area had a lot of carry-over nitrogen," said Crop Nutrition Specialist John Heard. "We were counting on that to help feed this 2022 crop and with excessive moisture and snow, that we had in April, we actually measured a bunch of those fields and learned that, yes there had been some movement of that nitrogen, even in the clay soil it moved from the top six inches into the subsoil. Not a problem because we still get most of that. On average, fields were about 35 pounds less nitrogen on the clay. A lot more losses on sandy soils because they leach quite readily."
Heard commented further on the wet soils.
"A real problem is once any soil gets water logged and standing water on it, then nitrogen, once it's in that nitrate form, the soil bugs run out of oxygen and then they start using our nitrogen and they gas it off as N2 gas, which is of no use to the farmer. Those losses can be pretty high in Manitoba conditions when soils are cool. We lose two to four pounds of nitrogen a day, under those saturated soils and it's even greater than that once the soils warm up."
Manitoba Agriculture says in-crop nitrogen-deficiency symptoms are showing up as chlorotic (yellowed) leaf margins, in combination with other symptoms of crop stress due to saturated soils.
The province notes a drop in nitrogen prices (down approx. 30% from spring highs) may encourage in-crop top-dressing.
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