Tracking Growing Degree Days (GDD) for Wheat Green up and Field Management

By Dale Cowan

On our website we have a link to see the accumulated Growing Degree Days for winter wheat development. A GDD is calculated by taking the high temperature of the day plus the low temperature of the day average them and subtract zero. Winter wheat is considered a base 0C crop, in other words wheat growth responds when average temperatures are above zero. GDD is a thermal, time measurement that allows us to track the time interval between critical growth stages. It does take a significant period of days above 10C for dormancy to break. Even it does occur, dormancy can reset with colder temperatures but depending on the duration, cold tolerance may be slightly less than before.

We track GDD from January 1^st and on, once we reach an accumulation of 250 to 270, we start to see green up occurring. This is the beginning stage of stem elongation of Zadok’s 30.Most years that can occur as early as first week of April to the 3rd week of April.

Accumulations of GGD2023 to 2024 Jan 1 to Feb 14, very similar year over year. Most of this year’s accumulation occurred in the past week of February.

Green up is the time to assess crop stands and do plant and stem counts. Determine the yield potential and decide on the Nitrogen application timing and rates of Nitrogen.

One of the services we are looking at is using our drone to do plant counts and create a field level view of stand density amongst other measurements. The program that utilizes the drone is from the UK a company called Skippy Scout. The following images are from their website that gives you an idea of what the service can provide.

A field level view of plant density

Each image position you can drill down to see the actual plant stand

A report is generated of field statistics to aid in making management decisions

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The Pursuit of Higher Yields

By Mark McKerrall

Can you believe it was 1975 when Herman Warsaw set a new corn yield record of 338 bu/ac? Here we are 49 years later almost giddy if we can average 200 plus bu/ac. What’s it going to take for us to reach that lofty goal of 300 bu/ac?

Fred Below from the University of Illinois has been doing research on this very topic.

We first need to start with good drainage, excellent weed control, proper soil ph and adequate levels of p and k based on soil tests.

There are 7 factors to consider when you are trying to push yield.

Weather is the first factor and as we have felt this year is the most limiting and uncontrollable. It has the largest impact on yield at 27% with an estimated 70 plus bushel/ac. affect.

Nitrogen is the second limiting factor that influences yield by 26% with an estimated 70 bu/ac affect on yield. Source is not as important as having the right amount to finish a 300 bu crop. Use nitrogen stabilizers to minimize losses and when sidedressing nitrogen use the nitrogen calculator to come up with the proper rates.

Hybrid selection is the third factor that can influence yield by 50% and can contribute up to 50 bu/ac yield response. Make sure you use a properly traited variety that is best suited for the type of ground you are on and disease and insect pressure present.

Crop rotation is the fourth factor that influences final yield by 25%. You can gain up to 25 bushels by following a good rotation such as wheat that was under seeded to red clover.

Plant population is the fifth factor at 20% which can positively affect yield by as much as 20 bushels. However, by increasing plant populations you increase inter-plant competition which must be managed. Response to higher plant population is heavily influenced by the weather, nitrogen availability, and hybrid selection.

Tillage is the sixth factor which can influence yield by as much as 15%. If you work the ground too early, too wet, too deep or too shallow you may be creating an uneven seed bed. This can cost you up to 15 bushels

Fungicides have proven to be the final piece to producing high yielding corn, which contributes 10% toward your final yields. Fungicide applications have become extremely beneficial over the years, especially in high disease years. Statistics over the years have shown a 9 bushel increase over untreated acres. If heavy disease pressure is present from Tar spot, Northern Leaf Blight and Grey Leaf Spot, yield increases of 20-50 bushels have been obtained.

These are the 7 basics to maximizing yields. With crop prices retreating from past historic values, growing need to produce the most bushels they can to maximize their production. Contact your local AGRIS Crop Specialist to see how you can maximize your yields.

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Assessing Winter Wheat Stand

By Jean Marc Guilbeault

It may be a little early but with Wiarton Willie not seeing his shadow this past Groundhog Day predicts spring is just around the corner. As the temperature starts to rise the winter wheat crop will emerge from its dormant state mid to late March and at this time every wheat producer should be actively conducting a spring stand assessment in their fields. This assessment serves as a foundational step in making well-informed decisions regarding crucial aspects such as nitrogen and sulfur programs, the application of fungicides, and determining the need for plant growth regulators. By thoroughly evaluating the wheat stand at this stage, producers ensure the overall health and viability of the crop, providing a solid basis for implementing precise and effective wheat management strategies as they move forward into the spring season.

To perform a stand count, measure the length of one foot of row and tally the number of plants on both sides plus average stems per plant . Repeat this process ten times randomly across the field, ensuring good representation and avoiding areas that are abnormal in that field. Gather 20 counts in total (two at each of the 10 spots) and calculate the average. A stand of 50 to 66 heads per square foot is a good place to be going into spring as show in the table below.

https://www.seedingrate.ca/#stand-assessment-calculator

Contact your local AGRIS location to start planning for a successful 2024 growing season today. Making good proactive decisions now will save you from making reactive decisions in season.