Spring Assessment & Nitrogen Fertility

May 10, 2017

Patience and Nitrogen Fertility is Key for Optimum Yield Potential in Winter Wheat

There are two things the agronomists at the Western Winter Wheat Initiative stress each and every spring: be patient and get your nitrogen on as early as possible.

“By winter months, the winter wheat crop will be at the three leaf, one tiller stage, and commonly, by spring, the crop will already be pushing a fourth leaf, with a fifth leaf shortly behind that,” says Lyse Boisvert, agronomist with the Western Winter Wheat Initiative in Saskatchewan. “Because winter wheat determines yield potential by the five leaf stage, it is critical at that time of development that nitrogen is available for the plant to reach full yield potential. That is why applying nitrogen as soon as you can get on the field is so important.”

According to Boisvert, winter wheat will start de-hardening when the crown tissue reaches zero degrees Celsius. This usually occurs mid-May in most regions of Western Canada. When the plant is fully acclimatized, the crown tissue will be nine degrees, meaning that it no longer holds any winter cold or hardiness within the plant. That is the time, she says, that nitrogen needs to be available to best support the crop.

“Because winter wheat does emerge so much earlier than other crops, timing is critical for the success of winter wheat, as proper nitrogen fertility can help with recovery as well as help control weeds later in the growing season,” says Boisvert.

Winter wheat requires very similar levels of macro and micronutrients as spring wheat varieties, specifically phosphorus, potassium, sulfur, and copper. For those producers who have excessive soil moisture in the spring, a split application, where some is applied in the fall, may be a better option as there will be less chance of leaching and denitrification.

Regardless of the application method chosen for nitrogen fertilizer, the most frequent error new winter wheat growers make is not meeting the needs of the crop. This often leads to unrealized yield. New producers often put down the same amount of nitrogen on their winter wheat as they do on their spring wheat, but this isn’t enough for the crop as it has a 20 to 40 per cent yield advantage – requiring more fertility. Using appropriate tools, such as a soil test, a tissue test, and the assistance of qualified agronomists, can help determine proper rates and application methods.

In terms of application, Boisvert recommends using 1.7 lbs of nitrogen for every bushel of winter wheat that the producer targets for yield. For 80-bushel winter wheat, for example, Boisvert suggests multiplying that by 1.7, which equates to 136 lbs of nitrogen. Some nitrogen will be already in the soil, of course, but a target zone of 90 to 100 lbs is optimal. Some producers will go higher than that because they may be targeting 100 to 110 bushels per acre.

“I really want producers to know that when managed properly, with timely spring assessment and nitrogen application, winter wheat can be extremely profitable and productive. We have seen it reach 120 bushels per acre under irrigation. And, of course, winter wheat supports land stewardship and sustainability, helping to minimize soil and water erosion,” says Boisvert.