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The Cropwalker - Volume 3 Issue 17

Always read and follow label directions.

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Crop Conditions

Winter wheat – earliest fields are at first node. This is about average for the last 8-10 years. It is ahead of last year. If weather warms up, wheat will quickly start to elongate. Cool weather will keep straw short. Once you reach 1 node visible, it is time to get the second application of nitrogen on and consider weed control and T1 fungicide applications. Most field have nitrogen on but there are areas in the Niagara area where it could be another 2 weeks before N is applied. There are a few reports coming in of Manganese deficiency. If you are not going to apply a herbicide, consider making a Fungicide + Foliar Mn application instead. In most cases of visible Manganese deficiency, a second application will be required. Ensure you are using a product with a high load of Mn.  Spring grains and new seedings have been planted at a quick pace. Most areas are 75% done. Wetter fields are waiting. Corn as of April 26th our survey reported about 5% of corn planted. As of May4th we believe about 15-20% of the corn is planted. Some growers are done other are waiting for field to dry. Picture below was taken May 3, planted April 25 light soil. Rye cover crop if not already sprayed off now is the time. Cereal rye will grow extremely fast with current weather. Soybean planting is just starting. Cold weather predicted for weekend has many growers parking the planter or drill. Check soil temperatures and if they stay above 50 F consider keep planting. Big issue is weather can not be forecasted with much certainty this time of year. Predictions are changing in a 12 to 24-hour period. Covid -19 Haven’t heard of any farmer or retail staff testing positive. Praying this will continue. Please keep your distance and wash your hands. I know it is hard, but the precaution will be worth it.

Picture 1 - Corn planted April 25, 2020 germinating


Corrections from Last Week

Thankfully it doesn’t happen very often, but we do miss editing or catching the odd error, thank you to the reader that pointed them out.

Error one was referring Roundup Ready alfalfa as Xtend and the proper term is HarvXtra. The second error, suggested that there are 3 actives in Miravis Ace, when in fact there are two actives. Miravis Ace is registered for spring, winter and durum wheat, and brings together propiconazole (Tilt - Group 3) and ADEPIDYN (Group 7), Miravis Neo used on corn has 3 actives (Quilt (Group 3, 11) + ADEPIDYN (Group 7).

Figure 1 - Miravis Family of Fungicides

What about spraying with current weather?

I’ve never run into issues spraying fungicides in cold or heat, but I’d want the temps to be above zero at the time of application when a fungicide is applied alone. If it was 2 C or lower at night, likely shouldn’t spray an herbicide until the day after assuming, it’s above 2 C at night. The wheat plant will break down the herbicide in the first hours after application so you want the plant to be actively growing. If it was 2 to 5 C at night then generally, we suggest waiting until another day to spray, assuming its 5 C or more at night. Generally, addition of other things to a herbicide will potentially increase the negative impact on the wheat. Main thing is a minimum 20 US gpa per acre herbicide or fungicide applied alone or tank mixed. This has all been known for some time, so nothing changes. The next 10 days or so do not look good for any post herbicide applications on any crop. I believe a large number of wheat acres will likely not get a herbicide this year. (comments from Brian Wooley - Syngenta)

Question Should I apply a fungicide at T1?

Answer If you look at the data from last week you can expect on average 1.6-2.0 bu/ac yield increase. The 1.6 is if you do not apply a fungicide later, the 2.0 if you apply two more applications of fungicides. There are a lot of on farm trials showing a higher yield increase by spraying at T1. While T1 application does not give as big a yield increase as the next 2 applications it is still worth doing. There is also an increase in the quantity and quality of straw. The exact yield increase really depends on what diseases develop. If we get bombarded with stripe rust the yield increase will be higher. With current weather you really should not be applying herbicides. There is nothing wrong with applying a fungicide. Thinking is we want to keep the leaves clean. Current weather slows down diseases. But it will be nice to get the leaves protected in case you cannot get in until flag leaf is well emerged.

Wheat Straw Length – (notes from Dr. Duane Falk formerly U. of G.) – Genetics is the main factor in straw length. Other factor determining wheat straw length is weather. (heat, length of day and intensity of light). Wheat changes from vegetative to reproductive depending on heat and light. Some varieties like the old R47 make the switch mainly based on heat. Thus, in hot years R47 plants switched over to reproductive early. Varieties like old lodging prone AC Morley, switch from vegetative to reproductive based on day length. If there is extra heat when it is still in vegetative mode it could produce another node and be taller than other years. The sunlight during elongation also affects straw length. If it is cloudy and cool from start of elongation until heading, the straw will be taller than if it is sunny during this time. Typically, straw length will vary but total straw dry matter will not change much. The cells merely get longer.

Why Multiple Modes of Action for Fungicides (Simplified version)

Last week we wrote about how strobis prevented spores from germinating and triazoles prevented mycelium from growing if they germinated. Fungi go through a rapid life cycle with lots of cross breeding. It is fairly easy for a disease to build resistance and get by one mode of action. If you have two modes of action, one will help stop spores from germinating and the other will help reduce the amount of mycelium growth of disease that got past the fungicide that should have stopped the spore from germinating.  Why not just use a triazole fungicide to stop mycelium from growing? Because some of the fungi will be resistant to that fungicide and mycelium growth will not be stopped.

Soybean Burndown Options

In most cases the rate will be based on the largest perennial in the field. Any newly germinated weeds will be controlled by the herbicide or rate selected for the perennial weeds. There are a few exceptions. 1) If you have glyphosate resistant summer annuals such as, Giant Ragweed, or Waterhemp, scouting will be critical to proper timing, and a tank-mix partner that controls the respective weed, 2) spring germinated Canada Fleabane, which should be assumed to be glyphosate resistant, will require a tank-mix partner with the glyphosate.

Figure 2- Soybean Burndown Options

Glyphosate Rate Equivalency and Effective Rate

Many manufacturers are now running 540 grams active/L of product. The bigger question is, what rate should I be using control the respective weed?

Figure 3 - Weed Control by Glyphosate Rate

If you don’t have a seed monitor or want to check your monitor this chart may help

Figure 4 - Soybean Seeding Rate and Seeds per Foot

Tillering and Stem Elongation in Winter Wheat

Last week we spoke about winter wheat staging the two main stages wheat will have reached this week are tillering (Zadok’s 20’s -> 21 = 1 tiller, 22 = 2 tillers, 23 = 23 tillers etc.) and stem elongation. Zadok’s 30 = stem has started to elongate, 31 = 1st node, 32 = 2nd node. To count tillers, first find the main stem, this is the biggest stem in diameter and typically the tallest leaf. (Red arrow below). Attached to the sides of the stem are the tillers (Orange and Yellow arrows). When planted early enough in the fall, with enough growing degree days, you will have 1-3 tillers going into spring. Late planted wheat may have no tillers or 1 tiller. The second picture below shows the difference between a fall-initiated tiller (dark blue) and a spring-initiated tiller (light blue).

Picture 2 - Winter Wheat Tillering
Picture 3 - Winter Wheat Spring vs Fall Tillers

Stem elongation is when the main stem, and tillers that will produce heads, start to initiate the reproductive phase. Agronomist Emily Jones has a good example below of the stems elongating, and how to find the first node.

When is wheat too big to use floater tires?

Once wheat starts into stem elongation or jointing, my rule of thumb has been 1st node is the cut off for running with floater tires. There is not reason in a year like 2020 to be using floater tires on big wheat at 1st or 2nd node (dry soils for the most part, can carry skinny sprayer tires), when the majority of the province has had relatively dry conditions. What happens if you do run on really big wheat? Biggest difference I have seen, depending on the soil conditions and time of day the application is made, is uneven heading date on the tramped areas. If you do need to run with floaters (i.e. spreading manure or only available machine), running in the middle of the day will reduce the amount of injury, when the stem is more pliable.

Belchim’s Manipulator - Tank-Mixing in Winter Wheat

The Belchim rep pointed out that the label for Manipulator is not registered for tank-mixes. If you are going to tank mix something, especially under current weather conditions, less risk with only two products in the mix (Manipulator + fungicide or foliar fertilizer), than three or four. You are on your own.

How to figure out how many grams per acre of micronutrient is being applied

You have two micronutrient products to pick from, both have some concentration of Manganese, how do I figure out how many grams of nutrient are applied per acre?

Figure 5 - Micronutrient Applied per Acre

Variable Rate Winter Wheat Seeding

Last fall a client had posted on Twitter a picture of them variable rate seeding winter wheat. A few commented they weren’t sure where they would start. Here are three pictures from a field that was not variable seeded. to give some clues There will be areas of the field that have the following cases in the chart.

Figure 6 - VR Wheat Seeding Quadrant
Picture 4 - High Mortality Rate, High Tillering
Picture 5 - Low Mortality - High Tillering
Picture 6 - Low Mortality, Lower Tillering

What is your favourite nozzle for applying liquid fertilizer to Winter Wheat?

Most of my application experience has been with dry fertilizer on Winter Wheat. However, the day the deal closed on the used field sprayer Chafer bars were ordered to be able to apply UAN on winter wheat. If you prefer to not use Chafer bars (they have to be put on and off (cannot use your triplets, and can be flimsy), pick the nozzle that would have the least amount of leaf burn, but the most amount coverage, usually a 5-hole fits the bill, for those running 20” spacing. Phil Needham of Needham Ag suggests that you will gain about 2-3 bushels on 100 bu/ac wheat using Chafer bars (Phil imports Chafers bars into North America from Europe). In Canada you can purchase them from Argis 2000 in Listowel, ON.

Chafer Stream Bars - Post Applying Liquid Nitrogen to Wheat To Boost Yield Potential.

Chafer Stream Bars - Post Applying Liquid Nitrogen to Wheat To Boost Yield Potential.

Here is a short video which shows the Chafer Multi-Rate Stream Bars in action on a Case sprayer. They are seen streaming liquid N into a wheat canopy using 2...

How Protein and Yield is Made in Winter Wheat – Notes from Brian Arnall - OSU

·      60-70% of the berry is starch (yes, that is what wheat scientists call the fruit of wheat), and 8-15% protein. Yield is mostly a starch accumulation in the wheat berry. Starch accumulates from photosynthates, protein accumulates through nitrogen uptake and relocation. Conditions that affect starch accumulation affect protein concentration, but not the total amount of protein. Greater than 60% of the photosynthesis for starch is fixed during grain filling (why we want to protect the flag leaf).

·      Starch is usually limited by the size of the sink. We have the supply of sugars in the leaves but are unable to transfer it to the grain. In dry years with high protein content, it had enough N to maximize grain yields, but was unable to transfer enough starch from the leaves to the grain to maximize yield. As a result, starch accumulation is very sensitive to environmental conditions.

·      Low protein wheat is source limited issue. Protein is derived from N translocated from other plant parts; 30% leaves, 30% stem, 10% roots, 15% glumes. 70% or greater of the nitrogen is absorbed prior to grain filling. 25-30% of the nitrogen is absorbed post anthesis. This 25-30% comes through the roots or a foliar N application.

·      10 days after flowering, wheat will start accumulating protein. By about milk stage, or 20 days after flowering, wheat will have accumulated 50% of it’s protein.

·      Total protein tends not to be affected by weather conditions during grain fill, but total starch is. Hot dry weather during grain means reduced starch accumulation, which means high protein content, due to less dilution. High rain fall means high starch accumulation, but reduced protein content if N rates are not increased. Cannot run out of nitrogen during grain fill if you hope to hit your protein targets.

·      The right rate to maximize yield in winter wheat is just below that to maximize protein content. If you have 11.5-12.5% protein content (on hard reds), yield was not limiting.

·      Nitrogen timing wise, 80% of nitrogen is taken up by flowering, 20% is taken up by stem elongation.

Figure 7 - Grain Fill and Protein Accumulation

To view the full video, see the link below.

Making Protein In Winter Wheat

Making Protein In Winter Wheat

This short video goes through how test weight and protein of wheat grain is correlated and impacted by the environment.

"Amateurs think reality is what they want to see. Professionals know reality is what’s true."

- Shane Parrish