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The Cropwalker - Volume 2 Issue 15

Always read and follow label directions.

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Crop Conditions

Winter wheat – more acres are now going to be ripped up. As fields try to green up, it is obvious that more acres will be ripped. The official OMAFRA number of acres planted was 952,000, some in the industry think the number planted is closer to 800,000. Either way, at least 25% will be ripped up. If weather turns suitable for cropping, more may be ripped. It appears that more acres will go into corn, than soybeans. Baling corn stalks when weather turns, several growers are planning to bale corn stalks. Since these have been left out all winter much of the fertilizer nutrients are leached out, making the fertilizer value of these stalks worth less than 2 cents / pound. There will be other costs to consider, such as compaction, loss of residue and timely planting of the next crop.  Forages – typically when we have a lot of winter kill in winter wheat, we lose forage acres. Once things green up, check all fields. Older fields and new seeding might be hit the worst but check all. Winter kill plays no favourites.


Spring Cereal Seeding Rate based on TKW

Last issue we reviewed seeding rates by seeds/ac. If you do not know seeds /lb. of your cereal seed, you may have the thousand kernel weight. TKW. If you don’t have that, check the Ontario Cereal Trials for average TKW. There is a large variation in number of seeds/lb. among varieties. Table gives seeding rate in pounds per acre by various TKW. See last week’s issue on what population to use.

Table 1 - Cereal Seeding Rate in lbs/ac to achieve various populations.

Metribuzin Rate by Product

Metribuzin is the active ingredient in Sencor, and the earlier product Lexone. Metribuzin is a triazine. It is used to increase ragweed control (of non-triazine resistant ragweed). Recently it is a main active in controlling glyphosate resistant fleabane. Research trials have shown that 215 gm/ac of metribuzin along with Eragon and Merge have given good control. Elevore plus metribuzin has similarly given good control. The original rate of metribuzin was 0.5 lbs/ac active metribuzin, which is about 220 gm/ac. That rate showed damage on lighter soils on some soybeans. The damage was worse on early varieties, such as the old Maple Arrow, the rate was reduced to 165 grams. This rate gives less damage, but less weed control. According to Steve Johns, Syngenta, he increases the rate of metribuzin when a grower uses 1.0L/ac Boundary LQ. The exact amount of increase depends on the soil type and grower experience. Conquest is a co-pack of Pursuit and Sencor 480, and Canopy Pro is a co-pack of Classic plus Tricor 75 DF so you can vary the rate of metribuzin yourself when using Conquest or Canopy Pro. Another co-pack is Bifecta, Tricor 75 DF plus Valtera.

Table 2 - Metribuzin Rates/Ac

Dicamba Rate on Roundup Ready 2 Extend Soybean Varieties

The Roundup Ready 2 Extend soybeans have taken off due to higher yields. There is also some concern about dicamba drift, but that is secondary to higher yields. The best way to use dicamba on these beans is pre-emerge, or early post emerge. This way you kill the small weeds, and have soil residual to control the next flush. If you delay spraying dicamba until the weeds are up, you will lose yield due to weed competition. Dicamba is both a knock down and residual herbicide. When using Dicamba in corn, we used to believe the high 240 gram/ac. rate gave us 4 weeks of residual weed control, and the lower 120 gm rate gave 2 weeks residual weed control. With corn there was a concern that rain on the high rate before emergence would damage corn. Since Roundup Ready 2 Xtend soybeans are resistant to dicamba, this is not a concern. The only dicamba products that you can apply to Roundup Ready 2 Extend soybeans pre and post emerge are Engenia, Xtendimax and FeXapan. Tavium is currently registered for pre-emerge application. These products all have ingredients to reduce the risk of drift.

Table 3 - Dicamba Rates for Xtend Soybeans

Management Influences Inputs Response

I strongly encourage producers to do their own on-farm trials, provided they have the time and aptitude for it. A large part of this thought process is that your management style is one of the biggest factors on whether you will get a response to a practice or input.

Take fungicide response in winter wheat for example; timing is certainly one factor, but so are variety, N rate, planting date, etc… that play into whether you end up with a response.

Fungicide Response in Spring Cereals

OSCIA Crop Advances data suggests that you should see a 10-20% yield bump regardless of N rate in either Oats or Barley by spraying a fungicide at T2 (Flag leaf stage). This does not include a value on straw quantity or quality. More on this topic once the crop is established.

Fungicide Response in Spring Cereals

OSCIA Crop Advances data suggests that you should see a 10-20% yield bump regardless of N rate in either Oats or Barley by spraying a fungicide at T2 (Flag leaf stage). This does not include a value on straw quantity or quality. More on this topic once the crop is established.

Hay Crop – Fertility Removal by Type

I don’t grow 100% alfalfa, what can I expect as far as nutrient removals on other hay types? Don’t forget there are volume differences between the different types/mixes.

Table 4 - Crop Removal by Hay Type

Cation Exchange Capacity (CEC)

While recently looking over a soil test, the conversation turned to how a field’s CEC can impact management decisions. CEC is a measure of the soils ability to hold on to positively charged ions, such as ammonium, calcium, copper, magnesium, potassium and zinc (not an all-inclusive list). The CEC is influenced by a combination of organic matter and clay content. As an agronomist, I would use CEC to gauge the following; risk of nitrogen losses, compaction potential, ability to tie up or release soil cations, and, subsequently build soil test levels. Also, CEC can infer soil type/water availability, and with a understanding of parent materials in the area, infer yield potential based upon water availability.

Pre-Emerge on Soybeans

Still on the fence on using a pre-emerge in soybeans? Depending on your weed spectrum, you could be giving up 10% of your yield potential by waiting to do weed control at the traditional V2-V3 leaf stage (2nd to 3rd trifoliate), plus have the risk of having glyphosate or grp 2 resistant fleabane. Here are expected net returns at 4 different yield levels. There are several products on the market in the $25/ac range for herbicide tolerant (RR/LL/Xtend/Enlist, etc) soybeans, see below. Soybeans are priced at $11.50/bu. If you currently apply a fungicide but not pre-emerge on your soybeans, I anticipate you will see a much more consistent return to apply a pre-emerge than the fungicide. (Notes from C. Swanton and Francois Tardiff – U of G)

Table 5 - Additional Margin with Pre-Emerge Soybean Herbicides

Maximum safe rates for corn starter

A very brief summary on safe rates of total actual N or total NKS in lbs/ac by fertilizer source in a corn starter.

Table 6 - Safe Fertilizer Rates in Corn Starter

Variable Rate Edible Beans

There is very little publicly available data on variable rating edible bean seed. A few pointers; 1) cutting the rate in half is likely to not reach canopy closure; leading to increased risk of weed escapes and being below the optimal economic seed rate. 2) Try rates that are 25-30% above or below your traditional seeding rate. Which one you choose depends on how you have defined your management zones and why you want to adjust the rate in the specific area. 3) Don’t forget to check final plant stands, different areas of the field will have different emergence rates. Make emergence notes to fine tune future scripts. (Notes from Meagan Moran, OMAFRA Edible Bean and Canola Specialist)

N rates based upon CEC?

Folklore suggests that a rule of thumb is that a soil will hold 10 lbs of Nitrogen per soil CEC. A soil with CEC of 10, would then be able to hold 100 lbs of commercial N. The issue being that the main factor that holds ammonia nitrogen within the soil is water. And then it converts to ammonium, which then converts to nitrate. The only form that is held onto the soil is the ammonium form. Should you base your N rates on CEC due to leaching (movement into the soil with water) or denitrification (gassing off due to lack of oxygen) potential? Certainly. CEC can provide an indication that you maybe prone to N losses due to soil type. For more information on this topic, see the following article; https://www.agvise.com/educational-articles/cec-and-holding-n-in-the-soil/

"Just remember, your dream is your dream. It may not seem important to others, but that's because its not "their dream". Keep pushing, keep fighting, keep moving forward, and, eventually they will wonder where and when you passed them by. "

- Al Seiber