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The Cropwalker - Volume 4 Issue 12

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Comment from a reader – I enjoy reading the newsletter but sometimes I get a bit confused. One week you say one thing and the next week something else. Answer A number of reasons. 1) We want to give you the most up to date information we can find. For instance, this week I found some research from Purdue that suggests some soybeans need sulphur (S). This is after we have written many times, we can’t get a response to S on soybeans. 2) Not all agronomists agree on certain topics. We try to give you the source of information. 3) There are times when the two writers will not agree 100% on the topic. Then you will get 2 opinions. For the main agronomy topics, we try to be clear as to what we mean. 4) Sometimes there is an underlying reason why the researchers will get a response in one area on one crop, but not in another area in the same crop. We don’t always know what that reason is.

Crop Conditions

Winter wheat –Ryan Benjamins says that about 80% of his wheat has some nitrogen applied in the Sarnia area. Susan Gowan in the Niagara area says about 70%. Other areas are 10-50% done. No issues with winter kill. Wheat is greening up. We are not out of the woods yet but generally wheat is off to a good start. Other seeding some spring grain, sugar beets and new forage seedings started last week. Wet weather has put a stop on most crop field activities. One of the first activities will be broadcasting fertilizer on soybean ground.


Zoom meetings I think we all have had our fill. I will be glad when we get back to real meetings. I spoke with one Huron county farmer who said “I am so done with Zoom meetings that after the last one I went to pick stones”

When to start planting corn?

If soil is fit target week of April 7-12 to start. I mean try out all the equipment to make sure things are working. This is when you check the planting depth ON ALL ROWS and check seed drop ON ALL ROWS. Then once we hit April 15-20 plant as many acres as are fit. Seldom are the first planted the highest yielding. But typically, the latest planted is the lowest yielding. You want the latest planted acres to be planted sooner than later.

Q. Will early N increase wheat lodging?

No. Not from my experience. Lodging is influenced by variety first, residual N and P from manure, and weather during stem elongation. Cool overcast weather during this period can increase lodging by making the stems longer with less lignin. Hot sunny weather during this period reduces chances of lodging. This is less of an issue now that most producers grow semi-dwarf wheat.

Q. What is the talk about no applying N too early if you have lots of tillers?

Answer - I have looked many places for research to back this up. Only place I can find anything is wheat guru Phil Needham from his Kentucky experiences. I can find no data from Ontario to suggest that you should delay N application on wheat if you have a lot of tillers. (From my experience you will not lose that many tillers in a thick crop by delaying nitrogen. It may help a bit with disease management and lodging. You will, however, prevent tiller initiation on a thin crop by starving the plant from adequate nitrogen.)

Q. Can I under seed alfalfa into winter wheat?

Answer - NO! I know this is being suggested. But it doesn’t work. You end up with a poor stand that you wonder about keeping or destroying. Either way you lose. I have seen it tried many times, but never successfully. You can under seed winter wheat with red clover, or seed alfalfa after wheat harvest. Crop Insurance will not insure alfalfa under-seeded to winter wheat.

Q Should I apply nitrogen to a cereal rye crop that will be harvested for forage this spring?

Answer - Yes. You need at least 40-60 lbs./ac actual N. If you applied manure last summer when you seeded your cereal rye, some of that nitrogen will be available. But not sure if it will be available for early spring growth. Suggest you apply some nitrogen this spring if you applied a low rate of manure last year. You can apply it at same time as you are applying your first split on winter wheat. Any nitrogen that is not used by the cereal rye can be used by the corn crop that is planted after you harvest the cereal rye. I also recommend adding at least 10 lbs S/ac to maintain protein in the feed.

Sulphur Release from Manure

Does sulphur release from manure? Yes, eventually. But it is in the elemental form and requires the right weather conditions to release. Don’t get caught being short on sulphur on cool season crops if you are depending on manure releasing sulphur. Generally normal rates of manure will not have enough S to add what a corn crop removes.

Should I put sulphur on soybeans?

Responsiveness to sulphur on soybeans has been variable. In most situations I would not do a separate trip to just add sulphur. If you are a grower with average soybean yield expectations, and use sulphur on other crops, likely not worth adding it. If you are a grower that does not add sulphur on other crops, or are seeking additional yield, consider adding it to your cropping plans. (thoughts from 2020)

Dr Shaun Casteel of Purdue University has done some very insightful research.

He says that there is a C: N ratio and a C:S ratio. The C: S ratio of plant material varies from 125:1 for soybean stubble to 400:1. Corn stalks are 350:1. S can be tied up with C or released from organic matter when soils warm up. That is why wheat and alfalfa respond to S, because the soil has not warmed enough to release it early spring. He also says you can count on 3-5 lbs of plant available S per % organic matter. A 50 bu/ac soybean crop needs 18 lbs/ac S. A 75 bu/ac crop of soybeans requires 26 lbs/ac S. So, if you are on a soil with 3.5% OM you can count on 10.5-17.5 lbs/ac S released. He counts on 5 lbs/ac S coming from the sky.

So, if a 50 bu/ac needs 18 lbs./ac S, on a 3.5 %OM soil you have 15.5-22.5 lbs/ac S. So, you may have enough. But if you have areas in the field where the yield is 70 bu/ac you may be deficient in S. In his research broadcasting AMS right after planting gave the best response. There are a lot of other variables like cover crop and previous crop. To hear his presentation click here; Dr Shaun Casteel Soybeans: Element of Sulfur: Surprise

So that are two reasons you will get a response to sulphur in soybeans. 1) the soil cannot mineralize enough due to low supplies; one grower has seen a 5 bu/ac yield response to side-dressing sulphur on soybeans on his sandy knolls. I do not know if he has been applying it on his other crops in the rotation.

2) you have sulphur immobilization following a large corn crop when planting into have residues. Seems like a great opportunity to band sulphur when no-tilling soybeans to help with that tie up (I have been hearing other producers doing this with some success!)

Fertilizer Test vs. Manure Test

A fertilizer test checks for plant available forms of P2O5 and K2O. A manure test has a total elemental P and K ran, not just the portions available that year to the plant. Generally, we count on 40% of the manure P being plant available in the year of application. Potassium is about 90% plant available in year of application. The % N available from manure depends on the amount in the ammoniacal and organic forms as well as the time to incorporation.

Fertilizer enhancers and soil amendments can be risky investments.

If you are concerned about what you are spending on your overall fertilizer program, cutting costs on products that have not been proven to consistently increase yield is a good place to start. There are several products on the market that claim to increase nutrient availability which are tempting as they can potentially increase the benefit of the fertilizer you are applying. The simple fact is that, in our years of research, we have never seen one of these products consistently increase yield. Even nitrification or urease inhibitors do not return the cost of your investment 100% of the time.

I will admit that every once in a while, we catch lightning in a bottle and we get a yield increase from a particular product we are testing. If yield is increased at one in five locations, or in one of three years, is that enough to warrant widespread use of a product? Consider that even fertilizer is not 100% effective at increasing yield in a low testing soil. What you need to decide is the probability you are willing to accept that something may not work. The issue is that, in many cases, the probability that no response occurred is not given so it is hard to determine the overall effectiveness of a fertilizer enhancer or soil amendment. It is best to invest your money in what you are certain will pay you back and avoid what likely will not. Dan Kaiser, Extension nutrient management specialist University of Minnesota.

The Three Stages of Weed Control

1.     That treatment is pretty expensive. Are you sure I really need that much?  (January to April)

2.    I don’t like the way my crop looks. I think the herbicide damaged the crop. (April to July)

3.    There are weeds here… shoulda, woulda, coulda for the rest of the season (July to October)

4.    Other option when a well laid plan was followed, and the weather co-operated “I sure like clean fields. “(July to October)

On-Farm Trials

In an earlier article we discussed on-farm trials and University suggesting you needed a particularly sized area to ensure the test being conducted was measurable. I would agree with them if you are blindly placing the trial within the field. However, we can and should do better than that. If you have a proper soil map of the field, you can direct treatments on similar response areas of the field, to take out some of the noise inferred by the university researchers that comes from differences in soil moisture, soil erosion and topography. Once you do this, you can decrease the size of the area required (in my opinion).

Question – Jonathan, how much would I gain by going to a planter for my soybeans with Downforce versus planting with a drill?

Answer – Assuming you are already planting on 15” rows with the drill, I figure you will gain 1 to 2 bu/ac in yield with the planter over the drill (both on 15” rows). I also figure you could cut your seeding rate to 160 to 170,000 seeds per acre. If you are currently seeding at 180,000 seeds with the drill, this means a savings of 10 to 20,000 seeds per acre. I feel you can likely even go lower, but best to take that approach in steps and assess what the right seeding rate is for your soil type and management.

Net return by planting instead of using the drill, I feel you will conservatively gain $10 to 24/ac from increased yield, and $5 to 10/ac in seed savings, for a total gain of $15 to 30/ac.

The value is in the fertility planning, not because it’s site specific…

Perhaps you are watching your peers applying their fertilizer with a shiny new spreader using the latest method of soil sampling and are feeling left out. I’m writing this to remind you that most of the value in fertility recommendations is in the planning piece and identifying short falls in the soil’s ability to meet crop demands. By going through this process, you may or may not identify the need to do site specific management. Even if you go as far as doing site specific soil sampling, you may still conclude that applying a flat rate is the right decision. But that is because the value is going through the planning process, not necessarily because you had site specific data. It just helped to make a better decision.

Wheat Staging – Understanding Greek…

When I was first exposed to wheat staging, I had a tough time trying to understand what the various terms/numbers meant. After working with it for a while, especially the Zadok’s system, it seems intuitive at this point what the various stages mean. The best guide I have found in recent years is the one produced by the University of Wisconsin-Madison. You get grab a copy at the link below. The reason I like this guide is that it covers both Feekes (US) and Zadok’s (Rest of the world including Canada) plant staging, which is important if you look to the southern neighbours for wheat management ideas.

Charts are from the wheat staging guide link below.

Cool Bean - Wheat Staging Guide

U of W - Madison

Figure 1 - Cool Beans Zadok's Scale vs Feekes Staging in Winter Wheat
Figure 2 - Cool Beans Zadok's Scale vs Feekes Staging in Winter Wheat
Figure 3 - Crop Staging by Crop Protection Application Timing

Nitrogen Uptake and Mobilization in Wheat

From research by Brian Arnall at Oklahoma State University. I realize this is from a dry land environment with lower wheat yields, but really like the research Brian is doing and feel the general principals around crop physiology apply here in Ontario.

1.     Timing of N application does matter, but yellow wheat does not necessarily mean yield loss.

2.    Two years in a row ALL Nitrogen could be delayed until hollow stem without yield loss, in fact yields of treatments with N applied at this time typically better than that of the pre-plant.

3.    Protein content increased as N applications was delayed.

4.    The conclusions of this and other studies support that N-Rich Strip concept does not increase risk of lost yield.

5.    Applying the majority of the N at or just after hollow stem maximized grain yield and protein with a single shot.

6.    Be more concerned about applying N in an environment conducive to increased utilization and less about applying at the first sign of N stress. Take a look at the wheat N uptake curve by K-State. The crop really does not get going in terms of N-uptake until jointing i.e., hollow Stem.

Figure 4 - KSU - Nitrogen Uptake and Partitioning in Winter Wheat by GDD

Nitrogen Management in Wheat – Why Split Apply Nitrogen

Have had a few questions on why you should split apply nitrogen on winter wheat? A few scenarios.

1)    You grow hard red winter wheat and need to meet a protein target to honor your contracts/meet grade. By splitting nitrogen application, you can reduce losses and ensure a portion is available to the plant during grain fill. In years with above average precipitation, you may need to do a third application post-anthesis due to above average losses/higher yield potential to meet your protein target.

2)    You have good ground conditions now, and the wheat is just starting to break dormancy, weather conditions look good, but you have light textured soils that are prone to leaching if you do get significant rain fall.

3)    You farm on very heavy textured soils, and struggle with getting nitrogen applied during the optimal window due to soil conditions. If you apply everything up front, you are prone to periods of denitrification.

4)    You want to manage based on yield potential, and are concerned that a portion of the field may not survive the March/April weather.

5)    You want to manage based on yield potential, and want to delay the 2nd pass to assess soil moisture conditions/rainfall, prior to making the final call on total N needs.

In all the situations above, other than if you are growing hard red winter wheat, this is assuming your wheat has not already reached stem elongation (Zadok’s 30). If you are already at this stage or later and have not applied any nitrogen, it is time to apply the full amount.

Finally, after going through Peter Johnston’s work listed on the OSCIA Crop Advances website with regards to splitting nitrogen on wheat, I would summarize the findings as, “putting rates less 100 lbs N/ac, no advantage to split, 120 lbs N/ac or more. It pays to split on soft red if not too late staging wise”.

Cover Crop/No-till Adoption by US State

Found this interesting, regardless of your views on the subject.

"Logistics beats agronomy seven days a week."

- Jason Hanson