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The Cropwalker - Volume 3 Issue 28

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Crop Conditions

Weather typical Ontario. Right now, some areas have great soil moisture and crops looking great. Other areas are dry to very dry. Winter wheat harvest is in the last 25%. Yields have been very good and great where there was soil moisture in June. Eastern Ontario yields are low. Central Ontario very good. Straw yields are also very good averaging 1500-2000 lbs. per acre. Numerous growers are opting to put straw back on the field. They are not satisfied with 3 ½ cents per pound. Fertilizer value is about 1 cent per pound. Red clover is looking very good where there was moisture. Cover crop - planting is ongoing. This is a great time to apply phosphorous fertilizer. Phosphorous should be worked in. A great option is to broadcast 2-3 years of P (keeping in mind to reduce requirements by the amount in your starter) with a cover crop and work every thing in. Corn - looks amazing where there is soil moisture. Other areas not so good. Western Bean cutworm are building, especially in traditional areas. Here is the trap site URL again https://www.arcgis.com/home/item.html?id=df7c044f224e4345825e75d1fa561560 The new disease Tar Spot is being found in Michigan and mid-west. So far it is not showing up in Michigan counties closest to Ontario. No reports in New York state. Soybeans are still flowering. Lots of mid plant flowers and pods starting. Some fields are aborting pods which is normal. Spider mites are still active and are coming showing up in areas that missed rain events. Forages all over the map from real shortages to lots. Will be opportunity to sell forages. Have about 2 more weeks of leaf hopper activity. Traditionally after mid- August we quit trying to control them as naturally their numbers drop.

Corn and Soybean Yield Estimates

A Twitter poll survey of readers came back with an average corn yield in Ontario of 167.8 (range 145-185) Soybean average yield estimate 45.9 (range 39-52)


Things to Do This Week

1.     Check wheat stubble and decide on a plan to control weeds before planting a cover crop.

2.    If you haven't already, arrange soil testing for all wheat stubble and check what other fields/farms need soil tests. Arrange for them to be tested once crop is off.

3.    Check alfalfa for leaf hoppers

4.    Check corn fields for western bean cutworm, weed control, evenness of crop and nitrogen requirements (nitrogen losses).

5.    Check all soybean fields for spider mites/aphids.

6.    Check that virgin soybean fields have nodules. Correct with nitrogen application of 50-75 units N if no nodules.

Cover Crops Seeding and Management

We have received a lot of questions so will try to answer them all in an organized matter.

In all cases you must decide on how you will control weeds. Preferred choice is a burn down before planting. Second option is tillage. This is especially appropriate if applying manure or fertilizer. Liquid manure is a great source of moisture and nutrients 5,000 imperial gallons per acre liquid manure equates to ¼ inch of water.

Reasons for a cover crop

They include, 1) feed, this fall or next spring, 2) build organic matter, 3) keep soil protected from erosion. 4) weed suppression 5) improve soil aggregation/infiltration. The species you use will depend on which of the above is your MAIN reason.

Cover crop for forage

The standard is oats. You seed at the traditional 2 bus/ac which is 68 pounds per acre. I can’t find any research to suggest a higher seeding rate. A lower seeding rate will give more tillering. Planted right after wheat you will get a good yield if you apply 40-50 lbs. N and spray a fungicide. All oats grown in Ontario develop rust (will be some differences between varieties on susceptibility). Any of the common fungicides will control rust on oats. Spray at flag leaf or earlier if you see it developing. You could get some regrowth this fall. It dies over winter, typically no problem with green growth next spring. There have been fields where a lot of top growth interfered with spring seed bed. In that case light tillage or cleaners helps. Addition of peas an option. Peas are normally sown at about 120-130 lbs. per acre. Sowing 10-20 pounds per acre should increase protein a bit in the feed when planted after wheat. Many common mixes are a 50/50 mix, or a 25/25/50 pea mix. These are usually seeded at 100 lbs./ac.  Research has shown a 50/50 mix can increase protein by 2-3% depending on when harvested.

Cereal rye Does well after wheat. Probably will out yield oats and you do not need to spray for rust. There is winter rye and spring rye. For cover and a crop this fall plant spring rye. For cover this year and a crop next spring plant winter rye. I have not heard of anyone planting a 50:50 blend to get feed this fall and next spring. But it should work. Cereal rye weighs 56 lbs./bu and is seeded at 1.5 to 2.5 bu/ac. Higher rates if broadcasting with fertilizer and working in. You will need to cut above the growing point of the winter rye to ensure it over winters. There are producers putting down a mix of Oats and Winter Rye as well.

Triticale can be seeded instead of rye. Triticale is a cross between rye and wheat so expect yields similar to cereal rye. There is also spring and winter triticale. Spring triticale should be planted if you want a cut this fall. Winter triticale requires much more management. More in a future issue.

Annual Rye grass (Forage type) Is a favourite with dairy farmers. If you source the right seed, expect a good cut this fall and also next spring in time to plant soybeans. A nice rotation is wheat, annual rye grass, soybeans then corn. To get best yields you need either manure or fertilizer nitrogen at planting and next spring. You need a minimum of 40-50 N and ideally 10 units of S each time. Seeding rate about 20 to 40 pounds per acre depending on species.

Building Organic Matter (OM)

All of the above forage suggestions will build OM. Leaving top growth increases the amount of OM. However, the underground organic matter is more crucial to building soil OM levels long term. If you want to build organic matter the best way is to apply nitrogen (25-40 lbs./ac) to get more growth. Some of the other annual cover crop species will add organic matter but probably not statistically more than oats, cereal rye or rye grass. The addition of other species can help build the diversity of soil microorganisms, but I cannot find any research to show a yield benefit to multiple species.

Protecting against erosion

The traditional crop has been cereal rye. It will control weeds especially the current strains of Canada Fleabane. We have seen how this species adapts so it may adapt to cereal rye but currently has not.

Dealing with Soil Compaction

There is research in Kentucky on fragipan soils (cement like soil structure) showing that annual ryegrass is the best cover crop in breaking up and dealing with soil compaction on clay soils. The caveat is trying to terminate it and ensuring the seed source you bring on farm does not have glyphosate resistant species. If it does you can control it with a number of herbicides in both corn and soybeans.

Other Notable Cover Crops

Red clover is still a favorite of mine, but the acres goes down every year. You must control fleabane in the fall and there are lots of opinions. If you have red clover and it is patchy you can no till oats into the field. Where the clover is good oats will not grow. Red clover will add more soil organic matter than the annual cover crops. Too late to establish at this point in the season. If you want a fall seeded clover, most common is crimson clover.

Sunflowers are very showy in a cover crop. You do not need very many. A full stand of sunflower is about 20-22,00 plants per acre. There are about 5,000 seeds per pound of sunflowers. I made the mistake of planting 2 ½ pounds of sunflower for the cover crop demonstration last year at Canada's Outdoor Farm Show. Result was they overtook the other species so we had to cut them off. So, quarter to half a pound of sunflower seed is lots.

Summer Seeding alfalfa

Lots of options. Main things are no weeds at planting and good seed to soil contact and good soil moisture. You want seed in a firm seedbed no deeper than ¼-1/2 of an inch. Hard to get. You need a good seedbed. Cannot have lumps. If you are spreading manure, make sure seed bed is not compromised (lumpy) because you are incorporating manure. I have seen successful stands with no till drills, conventional drills and broadcast seeding. You have to control weeds. If you have a lot of chickweed, you must consider sowing a Harvxtra (Roundup Ready) variety. Wait for weeds and alfalfa to emerge. Spray off the chickweed and volunteer wheat, then plant your grasses. If using non-glyphosate resistant alfalfa, you could wait for volunteer wheat to come up, spray it off, then plant alfalfa (or just use a graminicide in-crop). If you plant a cover crop with a summer seeding you are pretty well guaranteed the stand will be at best 50% next year. DO NOT USE A COVER CROP WITH SUMMER SEEDING OF ALFALFA. Note from Iowa extension folks Seeding depth is important since most forage species are small-seeded. Final seed placement should be no deeper than ½-inch for heavier soils and ¾-inch for lighter soils. If seeding with a drill, it is recommended to set the drill at the ¼-inch depth. You should see approximately 10% of the seed visible on the soil surface. If you are seeing a smaller amount, the seed is being placed to deep, and you need to adjust your seeding depth.

Ozone (O3)

Is a product of incomplete combustion. Sunlight reacts with these gases and produces ozone (O3). Ozone is heavier than air. If there are no air turbulences, ozone will settle and affect crops. If you have ozone levels at over 8 parts per billion for a few hours plants will be damaged. Damaged leaves appear as bronzed and take on a leathery appearance. We have been in weather conditions that produce high ozone levels. If there is air movement this mixes the ozone into the atmosphere. Crops that are under moisture stress generally are affected worse. Young and actively growing plants can withstand higher levels of ozone. The effects of ozone are irreversible. Crops most at risk are early planted edible beans with 3-inch pods or longer that are under moisture stress. These plants will not be producing new leaves.

Ear Leaf in Corn

The video below highlights the importance of the ear leaf in corn production. Winfield ran a trial where they removed all the leaves from the plant tasseling, the all the leaves above the ear leaf, and all the leaves at the ear leaf and above. Yield results in table below. (Yes, there is an advertisement at the end of Winfield adjuvant, but the importance of ear leaves is great.)

Figure 1 - Yield Impact by Corn Leaf
Plant Physiology Demonstration

Soybean Staging

I find myself reviewing exact staging at this time year to ensure the scout reports I am writing are accurate. I would provide credit to who made the chart if I could remember where it came from.

Figure 2 - Soybean Reproductive Growth Stages

Pod and Stem Blight in Soybeans

The number two yield robber in soybeans that can be controlled in crop, after White Mould, is Pod and Stem Blight (Phomopsis). To control this with a foliar fungicide you need to ensure the product you are using is labelled for it. To my knowledge; Stratego Pro and Priaxor are the only two products in the Ontario market that could control both white mould and Phomopsis if you wanted to make an application at the R4 stage, your second white mould application, or for general plant health. If you are a seed grower, spraying for Phomopsis if you have had it in the past is a must. If you wanted to make an application for only pod and stem blight, Trivapro also has registration (Trivapro has white mould listed on the label, however, Syngenta has not promoted it in the past).

Crop Protection Network

Pod and Stem Blight Factsheet

Root and Stem Rots

I have been getting the odd picture asking why my soybean plant looked good and is now dying. In most instances it will be due to a handful of root rots, those are; Pythium root rot, fusarium root rot, Rhizoctonia root rot and Phytophthora root and stem rot.

Soybean Disease Diagnostic Series — Publications

This series aids in disease identification.

Chimera in Soybeans/Edible Beans

This is a genetic defect where the leaves do not produce chlorophyll, and rely on surrounding leaves to support the leaf with the defect. The leaves are typically yellowish in colour. Sometimes it can be confused with insect transmitted viruses. Typically, there is no speckling or leaf distortion if it is Chimera. Thank you to Allison Hayward of FMC for sharing the photos.

Picture 1 - Chimera in Soybeans - Allison Hayward - FMC

Should I still spray beans for white mould?

For some growers the weather conditions have changed, should you still spray? If you have flowers still on the plant, and conditions are favourable, consider spraying at this point in the season. If there are no flowers on the plant to protect, you will not protect against white mould, but may get a response from suppressing other soybean diseases. Dr. Dave Hooker commented recent that soybean yield response is somewhat of a plateau from R2 to R4 if you are not trying to control white mould. Blair Freeman, Pioneer, has commented that in his area there is still a white mould risk at R3 to R4 due to increase branching with the newer soybean genetics. If the grower has had issues in the past, he is working with his clients to do a second application at this time if the canopy is wet. In dry years they will forgo the first pass and just do the R3-R4 application.

How many nodules do I need in soybeans to maximize yield?

If you had assessed at R1 to R2 that you had less than 10 nodules per plant (only 10 are required to reach 90% yield potential, regardless of size), consider topping up with 50-75 lbs./ac of N. Ideally this would be a dry product applied after the dew is off to minimize burn on the leaf foliage. Liquid products can be used as well but keep leaf burn in mind when decide what product and application timing/method. To get a response, the main factor is to ensure soybeans are into pod fill. If applied too early, essentially no response was noticed, see data below. Alternatively, if you want to do a nitrogen trial on soybeans. 1) Wait until pod fill, 2) do not use low rates of “safe” foliar nitrogen, put 50 or 100 lbs. actual N as topdress!

In the event of a inoculation failure or weak uptake, Pioneer rep Jim Van Nes of Stratford has commented they will spray soybean inoculant mixed with water prior to a forecasted rain event if they have a nodulation failure. They will do this at the R2-R3 plant staging. He feels he gets as good or better response to doing this as spreading nitrogen over the top.

Assessing Soybean Nodulation

Figure 3 - Relationship between Nodules and Yield Response (MB Ag)
Figure 4 - Soybean Response from in-crop N Applications (MB Ag)

What to look for when scouting for Western Bean Cutworm… it is not just cutworm. Doing a Corn Post-Mortem.

For a large portion of the province, doing Western Bean Cutworm field checks in corn is likely to be an exercise in futility. As is doing trap counts. Does every single agronomist, seed rep and retailer need to have their own Western Bean Cutworm trap? I don’t think they do. It’s better to work together on what we are seeing in a local area, rather than every running around each week to the same field to check if their trap has some more moths. (I have seen in more than one occasion where there are multiple traps at the same field, one for each supplier the grower works with. And thank you to Luke Hartung of North Wellington Coop for sharing his with a few of us in my area.) Once a given area is saturated with enough traps, to figure out that the moths are here, adding more traps to go check isn’t going to add more value for the grower, it’s just wasted gas, time and effort in collecting more data that adds very little value.

What does add value is doing a post-mortem on corn. The ideal time to do this is when the plant is at its peak. What is a post-mortem? It is figuring out what worked and what did not work for that cropping season. Ideally you are doing it during the early reproductive stages (tasseling/silking, maybe blister) because you are already there to look for WBC, but can also see how the crop performance was for the year, and what your management is currently limiting you from achieving your or the client’s goals. These limitations could be your nitrogen rate or timing, weed control, variability in corn silking or spacing due to planter performance, amongst many other issues. It is also a time to take an ear leaf tissue sample to evaluate the corn fertility program, to see if the plant is able to access what the soil test says is available, and to compare against benchmarks.

Picture 2 - Lots to scout for in corn besides just WBC

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