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The Cropwalker - Volume 3 Issue 8

Always read and follow label directions.

March 2020 Complimentary Issue; Next complimentary issue will be June 2, 2020.

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Crop Conditions

Red clover spreading has started. Keep rate around 6-8 pounds per acre. Single cut red clover supply is a bit tight. If planning on using single cut, best to get the seed home. Price for single and double cut is about the same. Some areas are cold and other areas are getting rain. Still too early for the first split of N on wheat. Corn harvest in central Ontario carried on. Now maybe 5% left to go. Moisture came down as predicted but bushel weight has not gone up as predicted.


Correcting Manganese (Mn) Deficiency

It is next to impossible to correct Mn deficiency by broadcasting or using Mn in a starter. The best solution is foliar spraying. If you have visible Mn deficiency, you need enough Mn to make a difference. There are numerous products with Mn, but many have a very low amount. For visible Mn deficiency you need to apply Mn two times about 2 weeks between sprays. Those products that can correct a deficiency will have to be a single nutrient product with a high load.

Winter Meetings

I overheard one person saying “I think me and my neighbours would be better off spending more time in the shop getting ready, than attending some of these meetings.” The reality is that there are some meetings every year, because there is a meeting. Organizations and dealers feel obligated to put on meetings. Often some speakers are of no interest to you. It is acceptable to go to a meeting for lunch or even to hear 1 speaker and then leave of go outside and do some other work or meet someone. Your winter time is valuable.

DON Testing 2019

The Ontario Corn Committee (OCC) ran DON tests last year at Ridgetown and Ottawa. Because the tests were so inconsistent and variable the results are of no meaning. The results will not be published. They opted to inoculate hybrids in groups. The results were that the earlier groups had more DON. The 2019 results were inconsistent with 2o18 results. Hybrids that were susceptible in 2018 were more tolerant in 2019 or vice versa. Also, Ottawa had higher levels of DON than the Ridgetown trials. It is felt that the Ottawa inoculation was more aggressive. The results did not show significant differences among hybrids. The bottom line is that weather after infection has a big effect on DON levels. You still must depend on your seed dealer to get you the best hybrid.

Tri-State Changes Phosphorous Test

The Tri-State Fertilizer recommendations come from Ohio, Michigan and Purdue university. They have spent a lot more on fertility research than Ontario has. In many ways their P&K research is more pertinent to Ontario than the 10-year-old P&K research than forms the basis of the Ontario fertility recommendations. For one thing their P and K recommendations take yield into account the same way as we take yield into account with our N recommendations for corn. They also use CEC as a basis for making K recommendations. At a given soil test they recommend more K for soils with a high CEC vs. soils with a low CEC. They have been working with three tests for P over the years. They use Bray P, ammonium acetate and Mehlich-3. The Mehlich-3 test is used because it extracts P, K and a number of other nutrients. This makes it less expensive test to run. In Ontario we use a sodium bicarbonate extractant as the official P test. Accredited labs in Ontario must be able to do a sodium bicarbonate extraction but can use another extraction if requested. The Tri-State have a formula that converts Mehlich 3 to a sodium bicarbonate rate. (Some believe it is now very accurate,) The most common P test used in Ontario is the Mehlich-3 even though it is not an accredited test. The Tri-State have just announced that the official test for Tri-State will be Mehlich. The sodium bicarbonate test is more accurate for soils with high pH. The Mehlich is more accurate for soils with lower pH. There are very few areas in North America that use the sodium bicarbonate test.

Watch Your P Test

Whether you use Mehlich, sodium bicarbonate, or Olsen there are some common elements. A high test for any extractant is high. Likewise, a low test is low. Probably more important to watch changes in your test. Have the values increased or lowered over 6-8 years or are they staying the same. If levels are going lower that means you are taking off more P than adding. If your soil is testing high this is a good thing. If your soil is testing low, you are probably giving up yield. Soil P levels as tested by a soil test will take a few years to show a consistent trend. Another point is that you should not switch the lab and/or soil sampler that does your soil testing, unless you plan to switch and stay there for a long time. Even using the same extractant there are differences among labs. These differences are due to things like sample size, shake time and age of extractant. Typically, an extractant is mixed up and used for a period of time. Labs who are using a lot of an extractant will tend to have fresher extractants. Bottom line you need to know your soil tests.

Differences in Cover Crop Varieties

Michigan State University Extension have started trials to compare cover crop species, mixes and individual varieties. From the report “At 33 days after planting, ground cover ranged from 29% to 89% for annual ryegrass varieties, while all brassica species/varieties had 78% or more. ‘Dixie’ crimson clover covered the ground quicker than berseem or balansa clover entries. ‘AU Merit’ hairy vetch covered ground quicker than the VSN hairy vetch check. Mixtures that grew more slowly tended to have little or no brassica in the seed mix (mixture proportions are available in the full report). Some brassicas, the oat check and the mixture check lost ground cover between 33 and 63 days, suggesting those varieties had already hit peak growth and were declining. In general, mixtures produced similar biomass to a single well-adapted cover crop.”

Valtera EZ

In the past if you have used Valtera or Valtera co-packs pre-emerge on soybeans, you may have been cursing trying to work with the dry formulation. For 2020, Nufarm is launching a limited supply of the Valtera EZ liquid formulation. In 2021, there is likely to be other liquid formulations of this product available in co-packs (i.e. Triactor). Advantages of the liquid formulation over the dry includes improved handling, sprayer cleanout, and more consistent weed control (Nufarm’s data shows 14% better weed control overall over the dry version). Should you want to try this version, and are looking for a liquid tank mix partner, BASF’s Conquest LQ (Pursuit +Sencor) has historically been a natural fit. You cannot tank-mix this product with Boundary (Dual) or Frontier.

Herbicide Tolerant Soybean Pre-Emerge Programs

Here is a list of my favourite pre-plant or pre-emerge, Roundup Ready pre-emerge programs. Most programs should be around, or less than $30/ac. Will follow up with Round Ready Xtend, Liberty Link, and Enlist programs next week.

Figure 1 - Selected RR Pre-Emerge Herbicide Programs

Authority 480 vs. Authority Supreme

If you are planning on using Authority this spring, ensure that you are using the “right” one. A chart with the differences is listed below. Essentially Authority 480 is the broadleaf product, Authority Supreme is a pre-mix of Authority 480 and a grass herbicide (pyroxasulfone). If you plan on using Authority Supreme, watch minimum residue limit restrictions on certain soybean classes (IP, NON-GMO etc.). Consider tank mixing Authority Supreme with Sencor to add residual fleabane control, especially at the 162 mL/ac rate. If you are planning on using Authority Supreme to control Waterhemp or Fleabane on it's own, I would recommended using the 202 mL/ac rate, or higher, as soil type allows.  The cost difference between the 162 mL rate and the 202 mL rate, suggests bumping the rate up is quite advantageous.

Figure 2 - Authority 480 vs Authority Supreme

Seed your spring cereals by seed count, not weight

Inevitably, I get asked, what’s the appropriate seeding rate for my barley, oats, spring wheat, triticale/peas… you get the idea. After I get past the “Well what seed count have you used in the past?” question, and come to the conclusion almost everyone seeds at 90 to 125 lbs./ac and otherwise has no idea, this is my article begging you to determine what seed rate you should be using. Below is an example of the variation in thousand kernel weight by variety in the OCC trials. And the corresponding number of seeds if you had seeded by a set weight (in this example 100 lbs./ac). Take a quick peek at the charts below, also keep in mind that, in some instances, the seed you may be growing was not grown in your local market.

I noticed in my field walks doing the spring grain judging at the local fair, is that growers are both seeding too light and too heavy. Because they simply do not know how seeds they are putting down. Do the math.

Figure 3 - Thousand Kernel Weight Range in Zone 2
Figure 4 - Thousand Kernel Weight Range in Zone 3
Figure 5 - Thousand Kernel Weight Range in Zone 5

What seed rate should I be using in spring cereals?

Like any agronomist answer, it depends. What’s your germination rate? What’s your seed mortality? What soil type are you working with? Have you had issues with lodging in the past? On loam soils with manure, you are likely wanting to be at the lower end of the range. With this in mind, a few notes on seeding rates.

1)    Adjust based upon crop species (see chart below)

2)    Ensure you adjust for differences in thousand kernel weight (TKW). The supplier should be able to provide you with TKW or seeds/lb. This is important as from 2019 area II results for Barley, you could have up to a 27% difference in weight to get the same number of seeds/ac in the ground (AC King TKW 49.3 gr. vs. Baden TKW of 38.9 gr). Last year this range was 45%.

3)    Finally adjust based upon soil type (plant mortality/tillering). Clay soils should be planted at the higher end of the range.

Figure 6 - Target Population by Cereal Species

OMAFRA Publication 811 - Table 4-7. Guidelines for cereal crop plant populations

Example calculation.

Figure 7 - Example of Target Barley Population Calculation

Seed Mortality vs Germination Rate

Until I had started working with variable rate seeding rates, I hadn’t paid much attention to the difference, but there IS a difference, because you will have different mortality rates throughout the field depending on your management zone. Which is one of the main reasons to VR seed in the first place. Germination rate will be the same across all management zones of the field, if you used the same seed lot. The mortality rate (number of viable plants), will differ across the field due to field conditions (soil crusting, too wet, too dry, smeared seed trench etc.).

How to read a soil test – Phosphorus

I was recently saving phosphorus soil test results into an agronomy program and thought it would be good to review what tests are available, and when you should use a particular test. Also have a list of comparable ratings, based upon ppm. I will follow up next week with an additional article on a teaser in the chart below. And the expected repeatability of each test.

Bray P1

Historically used in areas with acid soils. Will provide false readings in highly calcareous soils.

Mehlich 3

Behaves like Bray in acidic soils. Can provide false readings at low soil test P values in soil pH above 7.

Olsen/Sodium Bicarbonate

Standard and accredited soil test for phosphorus in Ontario, useful in areas with soil pH above 7 and high calcium carbonates.

Figure 8 - Comparison of Soil Test P Levels by Extractant by Subsoil P Levels

Amateurs think disagreements are threats. Professionals see them as an opportunity to learn.” – Shane Parrish