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The Cropwalker - Volume 3 Issue 6

Always read and follow label directions.

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There are numerous conferences we will be sharing content from. SWAC will denote Southwest Ag Conference, held in Ridgetown, ON. CCA will denote the Certified Crop Advisor Conference, and FS will denote FarmSmart or CerealSmart.


Last Week’s Mystery Weed

Last week’s mystery was…. Spreading Atriplex, which is part of the Lamb’s Quarters family. I know I have mistaken it for Lamb’s Quarters, but once you see it, and the fact that some herbicide programs may not control it, you will remember it! Growers that I have seen struggle the most with this weed have heavily relied on glyphosate at low rates as their main mode of weed control. Here are a few options that can control Spreading Atriplex

Corn – most consistent control has been using a combination of Atrazine with dicamba or Callisto pre-emerge. Options such as Marksman or Acuron would be a good fit.

Soybeans – for burndowns - use the 2 REL rate of glyphosate (1.34 L of 540 g/L Roundup or Credit Xtreme) when it is 2-4 leaf, early in the season, and use a pre-emerge such as Sencor, the combination that has provided the most consistent control.

Cereals – Refine M has provided the most consistent control, but I would rather see you use a group 4 like Barricade, Enforcer M/Trophy or Pixxaro, and save the group 2 herbicide use for your IP or NON-GMO soybeans. Infinity is also highly rated.

In-crop for RR Corn or Soybeans, OMAFRA data suggests that the 2 REL rate of glyphosate will provide acceptable control (90% +)

Picture 1 - Spreading Atriplex
Picture 2 - Spreading Atriplex

What Size of Corn Planter do You Need?

Math is simple. At 4 mph you are planting 1.2 acres per row. So, allowing time for fill and moving you can plant 1.0 acre per hour. Allowing you will on average have 100 hours to get your corn in you need 1 row per 100 acres of corn. The question then is should you get a bigger planter without dry fertilizer or a smaller planter with dry fertilizer. In most cases a smaller planter with dry fertilizer is the answer. A dry fertilizer system allows you to apply more fertilizer in a 2X2 band as well as get better placement of micronutrients such as zinc. One way to decide if your planter is big enough, is when do you finish planting compared to your neighbours?

Applying dicamba (Engenia, Xtendimax, or FeXapan)

We will keep repeating until there are no more issues with off target dicamba. These products should be used at the high rate pre-emerge or early post emerge, if this is in the month of May. To be using them in June or later is asking for problems. You can expect 2 weeks of residual activity from this rate. Under some circumstances you may have longer residual on some broadleaf weeds. If there is a lot of rain after application dicamba will move into the soil. This is not an issue with Xtend soybeans. It can be an issue with some corn hybrids since corn hybrids are not as tolerant to dicamba as the Xtend soybeans are.

Are you aware of buffer strips with pesticides?

Every pesticide has label statements as to the buffer strip between the product you are spraying and other crops or open water such as drainage ditches and fence rows containing trees. Do you know what the distance is? Most products are similar. A general buffer strip from water and sensitive crops is 1 meter. There is a move to have these buffer strips wider. As you continue long term plans keep buffer strips in your mind. A good buffer strip would be switch grass.

Switch Grass another cash crop

We have been growing switch grass in Ontario for almost 15 years. Switch grass has been used as a low potassium source forage for dairy cows. It has also been used for bedding. More recent uses are as a mulch in strawberry fields and hemp production. It is a simple crop to grow once established. You should expect it to last for 10 production years. It is established in late May underseeded to spring wheat. It does not like to be planted too early. Herbicide program is Buctril M. It responds to a moderate amount of nitrogen and a low rate of P and K once established. At establishment you would seed as any other grass., It is swathed around Thanksgiving and then harvested in the spring as dry forage. Usually as big square bales. Over winter much of the P and K leaches from the plant. This makes it a low potassium feed and reduces the need for replacement P and K. Seeding rate is 10-12 lbs/ac. Seed costs $12.00 / lb. Don Nott of Nott Farms at Clinton, ON is a seed supplier. He can be reached at 519 524 0193. He is also a director Ontario Biomass Producers Co-op, the co-op that buys and sells switch grass. They are currently paying 8 ¼ cents per pound for switch grass FOB on farm. According to Don Nott, once switch grass is established you should expect 8-10,000 lbs of switch grass on good land. Don believes the newer varieties that will be available in 2021 will yield closer to 12,000 lbs/ac with nitrogen.

From the Engenia label

Potential contamination of aquatic areas as a result of runoff may be reduced by including an untreated vegetative strip between the treated area and the edge of the water body.

Question: “I didn’t work my corn stalks last fall like I normally do for soybeans. Should I just no till, or work the ground?

Answer: If you normally work corn stalks before soybeans but did not do this last fall, consider using conservation tillage this spring. This will start corn stalks breaking down but more importantly size residue so you can do a good job with row cleaners or seeding soybeans with a drill. Consider leaving a small unworked check strip (you will have to do a burndown), to see if using tillage is working.

Know your Herbicide Groups

If you are attending crop meetings this winter, you are probably hearing about different herbicide groups. Some of the main groups are Group 2 which includes Pursuit, Pinnacle, Classic as well as Accent and Ultim. (Not all products within this group control the same weeds.) The main group being talked about is Group 4. This group includes 2,4-D, MCPA, dicamba, clopyralid (Lontrel), fluoxypyr (found in numerous products), Pixxaro and Elevore. This grouping generally means if a weed is resistant to one product in the group, it is resistant to all products in the group. The one point is that some products in this group will control weeds that other products in the group do not control. For instance, Engenia/, FeXapan/Xtendimax (dicamba) controls Canada fleabane at a low rate, 2,4-D works well at the higher rate, but that rate cannot be applied pre-plant to soybeans. Roundup or glyphosate is group 9. You can find all the groups and herbicide resistant weeds in the current OMAFRA Pub 75 Guide to Weed Control.

How Do I Apply Magnesium (Mg) If I Need It?

There is an area of Ontario that has high levels of Mg in the subsoil. Continuous cropping and tillage have brough some of this Mg to the topsoil. This area includes Bruce, Grey, Perth, Huron, some of Wellington Waterloo, much of Lambton and some of the surrounding counties. In this area, Mg levels are 200-300 or higher. These fields will not respond to more Mg. If you have Mg levels below 100 ppm, you need Mg. There are fields with Mg at 40-50 ppm. The easiest way to correct a low Mg level is with dolomitic limestone. Often fields low in Mg also have a low pH. For fields with pH above 6.5 but low Mg levels you have a number of options. 1) Broadcast dolomitic limestone, preferably in the fall. 2) Broadcast sulphate of potash-magnesia (sold as K-Mag or Trio) (22% K, 22% S and 11% Mg) or a similar product. Mg solubility is like K, so incorporation is not necessary. If your Mg levels are really low (around 50) I like to broadcast and use some in a starter. With a 3-year rotation of corn beans and wheat you remove about 60-80 lbs/ac of Mg.

The Five Percent Difference – 1 of 2 – I read an article recently that said the top 25% of producers are only 5% above average. You only need to do this on 20 areas of your business. I came up with a list of 10. Use your agronomist to find these improvements. Here are the first 5. 1) Corn population – 1000 extra ears/acre is about 6 bushels or $25/acre. 2) Corn Weed Control – one week delay in spraying is $14.50/ac. 3) Using the “right” rate of glyphosate – $3/ac 4) Calibrating your fertilizer spreader – Using $120/ac fertilizer cost – $4/ac. 5) Planting 200,000 vs. 240,000 RR soybean seeds – $65/unit – $18.60/ac See the next issue for remaining 5. Notes from Dr. Danny Klinefelter

Best Herbicide Programs for IP or NON-GMO Soybeans

First off, we are under the assumption that you are starting with a clean seed bed, no green plant tissue. If not, then a burndown combination of glyphosate, 2-4D Ester and/or Eragon + Merge will be required in most areas. When you put together the herbicide program for these soybean classes, you will want to have a combination of group 5 metribuzin and a group 14 herbicide such as Authority or Valtera. The reason being, these are the main products that will provide residual control of broadleaf weeds, such as Canada Fleabane, Lamb’s Quarters, Nightshade, Pigweed and suppression of Common Ragweed (even if it is group 5 resistant). I have found that Authority will suppress Ragweed, if the weather conditions are conducive, and pressure isn’t severe, otherwise Valtera based products (Bifecta, Diligent, Fierce, or Triactor) will provide more consistent control. Keep in mind neither are rated better than a 7. Authority is registered for Common Ragweed in the US, but at much higher rates than what we can apply here.

Then toughest question is figuring out which grass partner you should be using. You are limited to four or five grass partners in IP soybeans. The options are Boundary, Frontier, Prowl, Pursuit, or pyroxasulfone (Authority Supreme/Fierce/Zidua). One item of note is that pyroxasulfone does not have minimum residue limits established for all export markets, so check with your buyer prior to using that active. The grass partner you pick will depend on a combination of weed spectrum and economics of the tank-mix. Please note that you cannot use Boundary or Frontier with Valtera. See graph below for some possible options.

Table 1 - IP Soybean Group 14 Pre-Emerge Programs

Which is the better herbicide system, Xtend or Enlist?

I recently attended the Ontario launch for Enlist tolerant soybeans. That means that you can spray Liberty and 2,4-D Choline or Roundup and 2,4-D Choline in-crop. One question that has been brought up several times over the past few months is what is the better system? It depends. By depends, we mean what weed spectrum do you have? How do you plan on managing it? As a rule of thumb, dicamba is a great product to use pre-emerge. It has excellent knockdown activity, and when used at the highest labelled rate, you will have 2-4 weeks of residual activity. 2-4D Choline on the other hand will perform much better than dicamba in-crop. It is registered at a rate 60% higher than most growers can apply 2-4D Ester pre-emerge, and it does not have some of the off-field movement issues that dicamba seems to be having when applied in-crop.

Where can I buy Enlist Soybeans?

The Enlist trait has been shared with quite a few seed suppliers within the industry, you can expect to see this trait soon in the following seed bags.

Table 2 - Seed Suppliers with Access to Enlist Herbicide Trait

I have Waterhemp and Canada Fleabane, and I want to grow IP Soybeans followed by Canola?

I was posed this question last week. My answer, you can’t go to canola following IP soybeans and expect a clean crop. Grow a herbicide tolerant soybean, and you might be able to keep canola in the rotation. Weed control will dictate rotation restrictions, this is one example.

I don’t want to use a group 14 in my IP soybeans, any other options out there?

One that seems to be long forgotten about is Boundary + Lorox. The price of Lorox has increased significantly the last time I had checked (a year or so ago), but very few growers seemed to have weed escapes with this combination. It also allows rotational freedom for many crops for the following growing season. Lorox is rate sensitive. You need high enough rate to get weed control but not so high as to damage soybeans. You need to read the label and follow the planting depth restrictions.

Use a soil test as a probability gauge, not an absolute value.

I make this comment, because at times I have seen certified crop advisors, and to a lesser extent, growers get caught up on trying to balance a fertility plan perfectly down to the last lb. But that is not how fertilizer response works. There are also environmental factors such as soil moisture and temperature, and management factors around placement and timing of application. Then there are they physical factors such as spatial variation within the field and the effect of topsoil depth and concentration of nutrients within the soil profile. The best you can do is use a soil test to gauge probability of response, and the likelihood that the method of placement will improve your response. Therefore, when looking at a soil test report there is a given range, and a rating system. The rating system is an indication of the probability of response at that soil test level, when applying commercial fertilizer. These values are approximate, based upon on data and ratings from outside of Ontario. The chart below is an example of what this response could look like.

Chart 1 - Probability of Fertilizer Response by Soil Test Value

Root Residues by Crop Species

Continue to get a few questions on what species have the most root residues, here is a chart for comparison purposes by crop species. I would expect the red clover is based upon using it as a crop, not as a cover crop. The amount of root mass is one factor. The other is the longevity of that root mass. Roots of annual crops break down faster than roots of perennials. You like to have roots that break down over time to allow better long-term soil structure.

Table 3 - Root Residues Produced by Crop Species

"Amateurs think they are good at everything. Professionals understand their circles of competence." - Shane Parrish