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The Cropwalker - Volume 3 Issue 13

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Crop Conditions

In general, we are well ahead of last year and 2-3 weeks ahead of normal. Winter wheat is greening up nicely. Very little winter kill except on heavier soils. Even later planted wheat is greening nicely. Exception is some heavier soils in place like Lambton county. Lots of nitrogen being applied. Forages generally stands planted 2018 and 2019 are looking good, except for areas that had no rain last year. Fertilizer is being applied to these fields. If possible, apply S on this trip. Some new forage seeding and early spring grain has started. The earliest I have seen spring grain planted was March 17th. That year it emerged and had snow on it twice. Yield was great. Manure spreading - Fields are relatively dry so compaction should be minimal. Corn for most planting is still being thought about. Some growers are thinking April 20th. Consider planting a longer than adapted hybrid if planting April 20th. Some fields with a lot of weeds are being ”burnt down”. Next week we will have more on burn downs. The earliest I have seen corn planted was the year Larry Cowan in the Melbourne area planted some March 9, trying out a new planter. It was frozen off three times before he finally replanted it. Soybeans Some talk that it is better to plant soybeans early than planting corn early. I am still a bit skeptical of that. The rationale is that if you plant soybeans early and they are frozen off you can replant. Don’t know about that logic. We do know that longer season varieties can out yield shorter season varieties. If planting late April and the field will not be planted to wheat, consider a longer than adapted variety.


Spray off your volunteer winter wheat

The cultivator won’t take care of it, and winter wheat is very sensitive to glyphosate, so take the time.

Question - Should I still split my N on wheat?

Answer It depends. If you did not split it other years and were satisfied with yield it may not pay to split this year. Bigger question is what is the soil type and topography of your field. If you have a nice loam soil on a level field may not be a benefit to splitting. If you are on light soil or have rolling land consider splitting N. The other factor is work load. If you have lots of time splitting may be an option. If you are pressed for time splitting N is not as big a yield factor as getting some other jobs done. Once we get to April 15-20 limited value on splitting N on soft red wheats. Hard red wheat should have a split.

Nitrogen Volatilization

This type of nitrogen loss is greatly over rated (for winter wheat). I can find no research that shows any volatilization until soils reach a temperature of 45 F. At temperatures of 45-50 F the loss is very low, if no rain. Various researchers suggest that you need 0.1 to 0.4 inches of rain to move N into the soil to prevent loss. For wheat, the soil is usually not warm enough to cause volatilization. For corn ground, you can apply N, and if you do not get rain in 5-6 days, then work the N in. If you have that many consecutive days without rain, you should have time to work N in, and this working will also kill the small weeds.

Figure 1 - Volatilization of Nitrogen by Soil Temperature and Time

Question from a reader - How can growers make spring grain more profitable?

The biggest thing is to spray fungicides. The first should be applied with herbicide and the second one at flag leaf. All spring grain varieties suffer from numerous leaf diseases that can easily be controlled by fungicides. These fungicides increase yield and greatly increase straw yield and quality.

Figure 2- Average Fungicide Response in Spring Oats

Fertilizing Forage Fields Without a Soil Test

For fields with mostly grasses consider using 75 lbs/ac urea, plus 100 lbs/ac MAP/DAP/MESZ, 50 lbs/ac Sul-Po-Mag (for sulphur and magnesium) plus 75 lbs./ac 0-0-60. If pushing forages, repeat after first cut. If 50-75% alfalfa MAP/DAP/MESZ 100 lbs/ac, Sul-Po-Mag at 75 lbs/ac and muriate at 125 lbs/ac. Repeat after first cut if you are pushing the field. I generally add 1 pound of boron after first cut. (It is better if you have a soil test.) If you farm in an area with high magnesium levels, replace the K-Mag or Sul-Po-Mag with Ammonium Sulphate.

Figure 3 - Fertilizer Forages without Soil Tests

Is it too early to spread hay fertilizer?

No, ground conditions look like they are great. Get it done.

Question How can I control a heavy infestation of velvetleaf in IP soybeans?

Answer Number of options. You can use Pursuit either pre or post. Another option is Broadstrike. Broadstrike is a great product. When I first saw it in research plots in London I was blown away. The check plots had solid fleabane. The Broadstrike plots were clean. It is not used as a fleabane product because it is a group 2 and fleabane has since developed resistance to it. So, if you have glyphosate resistant fleabane, they could also be group 2 resistant. The same with nightshade. There are lots of group 2 resistant nightshade fields. Broadstrike also has activity on horsetail. In the new Pub 75 it is listed as one of the best options for horsetail control in corn and soybeans. It is listed as “8” for horsetail. One option is to spray Broadstrike on areas of the field where you have horsetail if you are using another program. You can use the higher rate (35 gr/ac) on soybeans pre emerge. In corn you can apply Broadstrike post up to the 8-leaf stage. Corn is more sensitive to Broadstrike, so only use the lower 25 gram/ac rate. One watch-out with Broadstrike is re-cropping restrictions, especially alfalfa and canola.

Figure 3 - Broadstrike RC - Labelled Weeds in Corn and Soybeans

Top Rated Products for Ragweed in IP Soybeans

According to research trials completed by Mike Cowbrough, OMAFRA, Boundary + Canopy Pro (Sencor + Classic) or Triactor /Conquest LQ +Valtera(Pursuit/Metribuzin/Valtera) had the highest rating. Typically, in IP beans I try to save the use of Classic for in-crop to control any perennial weeds, as it can only be used once a season. If the field does not have a history of perennials, great option.

Figure 4 - Ragweed Efficacy in Non-GMO Soybeans

Why Earlier Planted Soybeans Yield More

Plants reach V1 earlier resulting in earlier flowering (R1) and a longer growing season. Earlier R1 increases the length of the seed fill period. When plants reach V1 earlier, they accrue more nodes resulting in more potential pods and seeds per unit area. After V1, University of Nebraska research shows that nodes accrue at about 0.27 nodes per day, or, saying it another way, it takes 3.7 days to produce a new node. Internode elongation is dependent on temperature; in contrast, node accrual is time dependent. Earlier planting captures light earlier. Light "harvested" results in an opportunity to achieve greater yield. Early canopy closure reduces weed competition and evaporation from the soil surface and ensures more water availability for crop transpiration.

Pre-Emerge Programs for Roundup Ready Corn

I haven’t been the biggest fan of the sub $20/acre Roundup Ready pre-emerge programs. They have a fit in certain situations, however, I feel that if you spend another $5-10 per acre, you can get a program that would save needing to go back in until 7-8 leaf, and in years with adequate rainfall, maybe just for perennials. Plus, they provide better residual fleabane control even though there are quite a few options in corn to control this weed, at least as of today.

Round Up Ready Corn – Setup Programs

Acuron – 1.6 to 1.98 L/ac – Great option if you have bluegrass or waterhemp. Although with those two weeds, you likely want to use the full rate. One reason I like Acuron is that you can adjust the rate and have a wide range of application if you miss the pre-emerge window.

Converge XT – 20 ac/unit – I put this program out there, as I feel that it does offer good value on the main yield robbing weeds (annual broadleaves). It can be weak on grasses and it does mean that you cannot use a group 27 in-crop to cleanup other glyphosate resistant weeds. Another concern is that if you miss the window and weeds are up, needing to add Roundup means you have to use the setup rate (30 ac/unit). Usually suggest switch to another product at that point. And for those looking at your SRP, yes, it’s more than $25/acre, if you purchase other Bayer products, it will quickly be under $25/ac.

Engarde – 40 ac/jug + Aatrex @ 0.25 L/ac – Have had great luck with this program, especially on strip-till acres without heavy grass pressure. Watch out is that if you have used a lot of Ultim or Accent in the past, you likely have group 2 grass resistance. Depending on Callisto for your broadleaf weed control.

Integrity 0.3 to 0.45 L/ac – From personal experience, this product is really designed for burndowns on strip-till or no-till fields and as a grass herbicide. It is a strong option for those fields you want to inter-seed cover crop into corn, but because of that, it is weak on residual control of annual broadleaves. Can’t have everything.

Prowl @ 0.89 L/ac+ Broadstrike RC @ 25 gr/ac+ Aatrex @0.25 L/ac – With this program you will have used a couple of modes of action not commonly used in corn (Prowl or Broadstrike). Leaves the option open to use a Callisto GT style program in-crop for clean up at the 7-8 leaf stage. It is weak on fleabane, due to group 2 resistance.

One program I think that gets overlooked on spring strip-till acres is Primextra II Magnum + Broadstrike. This allows you do to do a burndown, then strip and plant. There are very few programs that you can spray up front and then strip-till, Integrity also being one of those.

Fierce in Corn?

Fierce – 85 gr/ac rate - is registered on field corn ONLY used in a no-till system. Label suggests to not use this product on conventionally tilled fields. There are a number of restrictions around timing of application (minimum 7 days prior to planting). Fierce has worked well in soybeans, but it does take more soil moisture or rainfall to activate compared to other actives. Would provide control of bluegrass, ragweed and waterhemp. I have no experience with this herbicide in corn, and reading the label, it does suggest not using on poorly drained soils. While I think Fierce can be a great fit in soybeans, there are more versatile products for your corn program.

Zinc – Best way to get it on the field

There are a few ways of getting Zinc on the field. If you are hoping to build your soil test zinc levels, the easiest and typically cheapest way is to buy Zinc Sulphate or Zinc OxySulphate dry granular products. Zinc sulphates are 100% available at time of application, while cheaper, oxysulphate based products require a period of time (sometimes years) to become available to the plant. There are several specialty products that try to overcome some of the challenges of using Zinc in a dry blend, a few examples of this are Yara Procote, Mosaic’s Microessentials SZ, AMP’s Corn-Mix and Midwestern Bio-Ag 5-5-5 with Micros. Most of these products are simply trying to increase the number of sites that the roots can intercept and are appropriate for crop response in the year of application but are usually not suitable for building zinc soil test levels. There are also liquid fertilizer friendly zinc products, this gets a bit more complicated, as you will have to pick a product that matches the carrier. Certain starter fertilizers can tie up zinc or go out of solution due to incompatibility, leading to sludge or plugged orifices. Lastly if you need to supplement in-season or correct a deficiency, there are foliar products available, which are typically the most expensive per gram of active (for several reasons).

Figure 5 - Brief Summary of Dry Fertilizer Zinc Sources

10-34-0 vs. 6-24-6 vs. a specialty blend In-Furrow for Corn

Liquid Fertilizer Starters, it’s all about maximum nutrients at acceptable seed safety at acceptable cost. I was asked about a product that advertises in quite a few farm magazines. My comment was the above, pick a product that has acceptable crop injury for the yield response, for the cost involved. One comment I would make is that if you have low potash levels, there does seem to be a slight benefit to adding a small amount of potash to the in-furrow corn starter.

Pick trials the combine monitor CAN measure.

Quite frequently I get push back from growers suggesting the combine monitor couldn’t measure the trial or that it won’t be statistically significant enough to make a difference. Well then pick trials that the combine can measure, adjust the trial based upon the margin of error your measurement tool can do. For most producers, if the combine can’t measure it, then it probably isn’t worth doing a trial on it anyways. I don’t use a micrometer to measure the boards I cut with a saw, nor do I use a tape measure when trying to mill something on a lathe. Use the right tool.

Thoughts on Strip-till Corn Herbicides

When you switch to a strip till system, especially if the strips are made in the fall, you are planting into stale seed bed. In this system the main yield robbing weeds becomes winter annuals, biennials and perennials. You will have to shift your weed control dollars to the fall, and in-crop, rather than as a pre-emerge chasing annual broadleaves weeds.

Jonathan’s Three Thoughts from December 2018

I was cleaning up a few notes from the past year or so and came across these three points;

1)    We grossly underestimate the impact water has on the crop and nutrient cycles

2)    Getting things done on time trumps technology or what’s “cool” every time

3)    Some growers are having a hard time building soil test p&k using conventional fertilizer.

Correction Wheat Chart

Re-reading last week’s wheat article, I noticed I didn’t catch an error in one of the formulas in the chart. Update chart below. Just a reminder that the assumption is the wheat was planted at the optimal planting date to have this yield potential.

Figure 6- Updated Wheat Plant Stand Chart

"Amateurs don’t have any idea what improves the odds of achieving good outcomes. Professionals do. "

- Shane Parrish