It’s time to look ahead and plan for a successful 2020 growing season. Taking a drive around the countryside, it’s hard to draw your eyes away from the healthy-looking wheat crop. This year, we find ourselves in a different situation compared to last year. With few wheat acres surviving the winter, the decision to burn off fields to replant to corn or soybeans backfired with the wet spring. With the acres left unseeded, this challenge turned into an opportunity to seed winter wheat through the middle of September into the first part of October. Aside from this, as the soybean crop matured more quickly than anticipated which allowed wheat to be planted around the optimum planting dates.
Wheat is the most management responsive crop we grow next to corn. As seen last year, the issue with low wheat yields is late planting- this year is a little different.
As crop planning for 2020 is beginning to ramp up, it is time to start planning management decisions for a wheat program- let’s start with nitrogen rates. The big question is “how many pounds of nitrogen should I apply?” Nitrogen rates should be determined on a field by field basis. The first thing to think about is the environment. When looking at a high yielding environment with good soil fertility or manure, we want to watch nitrogen rates as the risk of lodging increases as the nitrogen rate increases. Lodging is a major limiting factor in attaining high yields from increased nitrogen fertilization.
The next thing to think about is planting date and how high of a population that was planted. A thick stand and early planting date will result in more developed tillers which will also increase the lodging risk. In both of these situations, we need to consider applying a Plant Growth Regulator.
Plant Growth Regulators (PGRs) are a class of chemicals used to modify the growth habit of plants. Cereal PGRs fall into two main groups- Ethylene releasing compounds and Anti-Gibberellin products. Ethylene releasing compounds add the hormone ethylene into the plant. An example of this product is Ethrel which is used quite frequently in tomato production as it promotes the ripening of tomatoes. Anti-Gibberellin products reduce gibberellin production in the plant which reduces plant height and thickens the plant stem.
Manipulator (Chlormequat Chloride) is an Anti-Gibberellin product that inhibits early stages of Gibberellic acid production. Gibberellin stimulates stem elongation through cell division and elongation. By inhibiting Gibberellic production, Manipulator causes a reduction in plant height while thickening stems. This makes plants more resistant to lodging and allows us to push nitrogen rates in order to achieve higher yielding wheat. It has no impact on the amount of straw produced.
Manipulator has a wide window of application, from GS-12 (two leaf) to GS-39 (flag leaf stage). Below is four different scenarios for application of Manipulator.
- Applied with a herbicide at 0.7 L/ac between GS-22 to GS-23. This will significantly reduce the plant height and lodging risk but may not lead to an increase in yield.
- The optimum application window is GS-30 to GS-32- the beginning of stem elongation at the 5-6 leaf stage, at 0.7 L/ac.
- Applied with a foliar fungicide at 0.7 L/ac at the Flag Leaf Stage (GS-39) to protect against foliar diseases such as stripe rust. This will provide a reduction in height and can increase yield over the untreated check.
- Split apply between GS-22 and GS-23 at 0.4 L/ac and again at Flag Leaf (GS-39) at 0.3 L/ac.
Use caution when tank mixing with certain products.
Lastly, protect your investment by preserving grain quality at harvest by applying a proper T3 fungicide. to suppress Fusarium Head Blight. Keep a close eye on weather conditions as FHB is more likely during wet conditions such as rain, fog and heavy dew just prior to flower.
For optimal application, it is best to apply a T3 fungicide when the anthers have extruded in the middle of the wheat head, on 75% of the heads in the field. Spray when a majority of the heads are in between the pictures below.
To summarize, more nitrogen means more yield, more nitrogen increases the lodging risk. Plant growth regulators such as manipulator reduce the lodging risk. More nitrogen increases canopy density which creates a favourable environment for fungal pathogens. Applying leaf disease fungicides and heading fungicides to reduce the fungal load protecting the crop. A healthier canopy will use the additional nitrogen for more yield. More yield means more profit growing wheat.
This winter, let’s take the time to sit down with your crop specialist to come up with a programmed approach. A lot can happen between now and then – we have the time to make management plans now. Devising a plan costs very little, a missed opportunity can cost a lot.
Sources:
- Belchim Crop Protection Canada
- Bayer Crop Sciences Canada
- BASF