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The Cropwalker - Volume 3 Issue 44

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Crop Conditions

Corn harvest is just about done across most of the province. Probably 90-95% of acres are harvested. Some areas still have 25-30% to go. Yields have been very good if you got rain. There are reports of some very high bushel weight corn which is slowing down drying for on farm. But also corn barely making #2. Some corn on the weekend went down with the heavy winds. Winter wheat is showing various colours. (see below) Cover crops have really done well this year. Some cereal rye is getting a bit tall. Could be an issue next spring. But we will discuss how to handle that next spring.


Things to do this week

1)    Decide where wheat will be planted in fall 2021 and order an appropriate soybean variety for those acres

2)    Talk to corn seed folks about DON tolerance in new hybrids. Some of these new hybrids were not around in 2018 but DON is still an issue

3)    Prioritize spending for before year end

4)    Check winter wheat for off coloured plants and determine a solution.

5)    Make a field by field list of corn hybrids and required planting populations to finalize seed orders.

Multi-coloured wheat

Picture 1 - Field overview of multi coloured wheat
Picture - Close up of Multi Coloured Wheat

Some of these fields are rather picturesque. However, the field is trying to tell you something. What is happening is the plants are producing more sugars than they can use. The heat and sun the last two weeks really got the wheat growing. So, all of these sugars were produced but could not get translocated to the roots. The buildup of these sugars turns to anthocyanins which give leaves the red colour. The root system is restricted due to compaction. You can see in the field on the left there is redder colours in the wheel track where there is more compaction. This can also be caused by poor soil drainage. Also, the lower part of the field is more compacted. Water is not getting away form these spots. We are also seeing a lot of tile run fields which is a similar issue. These can be improved by getting more cover crop roots into the soil to improve soil conditions.

What did we learn about planting corn into cold soils?

This past spring there was a time when soil was fit to plant and a cold front was predicted to be coming in. Many growers planted after consulting with industry reps and other farmers. So, what was the result? In some field’s yields were good. In many fields there was a reduced population in fields that were planted around May 9th. Some of these fields had 5,000-10,000 fewer plants than fields that were planted 2-3 days earlier or later. How did they yield? In most cases they yielded very good. But there is an underlying feeling that they yielded 15-20 bu/ac less than fields planted 2-3 days earlier or later. After many people asking questions there is pattern developing.

Year old seed was planted in some of these fields. This is suspect of some of the fields with lower populations. Some of this seed was farm carryover. If you know how to read a seed tag you can see if you have year old seed. Year old seed must have 90% germination to be sold as Canada # 1. Some believe that year old seed does not have as much vigour even though it has 90% germ under standard germination tests. Some hybrids emerge better than others in cold soils. Most companies give a rating to help you decide. Some of these hybrids needed higher population to achieve best yields. Planting depth did not seem to make a difference.

What to do next time?

We will experience similar conditions in the future. When soils are fit but a cold front is coming in. Under these conditions you have to take a long look at your hybrid and ask you dealer if that hybrid will do well under cold soil conditions. For sure you must consider increasing population. This may lead to higher populations if cold front does not materialize. This may negatively affect some hybrids if the population is too high. Your seed dealer again can help decide if it is a good idea to increase population. Or you can just wait until weather improves. The downside of waiting is often you get rained out of the field for 4-5 weeks. In these years it is better to have seed in the ground. More yield has been lost due to fall cold weather than spring cold weather (especially in the lower heat unit zones). Finally, it is not just the yield of these early planted fields. It is also the yield of your latest planted corn and soybeans. If you lose some yield on early planted corn you could make it up on earlier planted soybeans and earlier planted winter wheat.

Buying Inputs for 2021

The good yields and good prices mean that there is some extra revenue in 2020. Some of this revenue from 2020 can be delayed into 2021. Here are some ideas in terms of where to spend money before year end. Some of the following comments have come from readers as well as Deb Campbell CCA ON of Agronomy Advantage

1.     First obvious is buying seed. You can even get some discounts for early ordering

2.     Purchase fertilizer. It does not necessarily have to be applied this year

3.     Purchase crop protection products. You may have to put a product name to get a receipt. Most suppliers would be able to switch products in season.

4.     Pay rent in advance. Not all landlords will go for this but ask anyways

5.     Tile drainage. Generally, cannot have enough. You may not be able to pay for tile installation, but you could buy tile and have them delivered.

6.     Equipment. I put this last since I think it will be number 1 on most lists. But take a long look at what you really need vs. what you want. You may want a new tractor but need a new sprayer or planter.

Why Corn is King

If society were to grow a crop, you would want to have as many uses as possible for that crop (food, fuel, fiber, animal feed, industrial), it would be interchangeable regardless of where it was grown, minimal skill set required to get a base level of return, adaptable to a wide range in climate or soil types, responds to management/inputs, stores well, can be quickly converted to cash. You would want it to be able to perform in a wide range of weather conditions. Minimal specialized equipment can be used to grow it, or the equipment needed adapts slowly over time. It should have a low water use per bushel relative to other crops and integrates well into existing infrastructure. This is why corn has been king of the field crops.

Starter vs No Stater vs What Form

I find discussing stater fertilizer in corn production can be a bit like asking who you voted for in the last election. Both growers and agronomists can get quite animated during the discussion depending on other factors in the crop program like location, soil types, background fertility, tillage program, fertilizer access, available planting time and crop rotation. But not wanting to share away from the having the conversation, I ran a Twitter poll on which starter program provides the best starter placement for corn response. Here are the results.

A few comments were added below the poll, here is a summary of some of the comments.

A few “innovative” producers commented that they like to use both liquid or dry in-furrow plus dry 2x2 as their preference or preferred system. This is a good option for low testing soils, especially on cooler soil types.

A crop consultant from North Dakota commented that the biggest ROI he has seen with his client base when using Precision planting’s Furrow Jets has been to apply using the sides of the furrow, rather than down the center of the unit.

A farmer from Michigan commented he drank the Kool-Aid and then went back to what works for him (dry 2x2 on the planter) which slowed down the planter, but made for a lot more work in the fall (more yield).

Another farmer/agronomist from Minnesota commented on corn on corn acres they run a 2x0 set up with UAN and ATS, and on corn on soy acres they run in-furrow with 10-34-0.

My opinion: the product (dry or liquid) does not matter as much as the placement and rates being applied. Regardless of soil test, starter fertilizer does remove in-field spatial and temporal (weather) induced variability. These are the factors where it is not practical to use soil test to increase the frequency or accuracy of the tests. What rates get applied and the products selected should be farm management specific (i.e. no-till/strip-till vs worked, corn on corn vs corn following soy, etc.…


Next week Patrick Lynch will add his take.

Question - I am reading my soil test report, the previous lab reported both Bray and Sodium Bicarb for measuring phosphorus, now the soil reports for the lab my consultant uses only has Sodium Bicarb listed, what is the difference?

Answer – Bray P1 was developed by Bray and Kurtz in 1945 for use on acid soils with a moderate CEC. In soils with a pH above 7.2, the Bray P1 test may significantly underestimate the amount of available P. The Olsen or Sodium Bicarb test, which is the calibrated Ontario test for phosphorus, provides a more accurate method of determining plant available phosphorus on alkaline soils than the Bray P1 test. All OMAFRA phosphorus recommendation tables are based off the Olsen/Sodium Bicarb test, if you are planning on using the Bray P1 test, you will have to do a conversion as the Olsen test provides a smaller numerical value than the Bray P1. See table below.

Figure 1 - Interpreting Phosphorus Soil Tests

Current Iowa State University Suggestions on Use of P Soil Tests;

Bray 1-P If soil pH is less than 7.4.

Olsen - If soil pH is above 7.4.  If soil pH is above 5.0

Mehlich 3 - Any soil.

See graphs below comparing soil tests results at various soil pH. Large amounts of scatter on the graph means minimal correlation (i.e. Olsen and Mehlich-3 vs. Bray P1 above soil pH of 7.4 or higher).

Figure 2 - Graph of comparing Mehlich-3, Olsen and Bray at various Soil test levels

Source: Dr John E. Sawyer – ISU - Differentiating and Understanding the Mehlich 3, Bray, and Olsen Soil Phosphorus Tests

Comment: I do not know how you can afford to take enough soil samples to use variable rate for anything but lime…

There is some truth to this which is why some producers will do grid sampling on 1- or 2.5-acre blocks and then the second time around sample in “reference areas” if they don’t require lime and are trying to manage their P&K site specifically. Many soil sampling strategies are moving to more of a zone style management, where you spend considerable time and effort up front to establish management zones that group soil response areas together, which are then sampled. This approach seems to provide a good balance between having a high enough resolution to capture variability and not mix soil fertility response areas. These areas can then be reused the in the future for the following round of sampling. How the soil test response zones are created is the secret sauce.

What is the Phosphorus Soil Test Reproducibility?

The reason I bring this up is for both Certified Crop Advisors and farmers to understand how “accurate” the tool is that they are working with.

For Bray 1-P and Mehlich 3 – both have a -/+ 10% repeatability on a dry soil basis, with 1 ppm detection limit. Olsen or Sodium Bicarbonate has a -/+12% repeatability with 2 ppm detection limited. This means that with an Olsen test here in Eastern Canada, a 6 or 7 ppm Phosphorus soil report are essentially the same. When it comes to using soil tests to design and build fertility response zones and the corresponding recommendations and application maps, it’s important to understand how much “noise” is built into the system and what the constraints are to applying a good fertility recommendation. (Notes from ISU)

Spatial and Temporal Factors That Influence Soil Fertility (Copy from 2019 CCA Article I wrote with a few updates)

The soil sampler has left the field. The samples have been sent to the lab. Now the results have shown up in your inbox. Your check over the reports. Your left wondering: “How has my location, and farm specific management impacted them?” One aspect of soil test results that may not be discussed is the impact of spatial and temporal factors. This is a brief summary of a few of those factors.

Spatial Factors

What has your soil started with

The parent material determines the background fertility through the type of limestone/minerology, clay/sand/silt content, and sub-soil. Natural vegetation will then have influenced the soil pH and nutrient accumulations over time. These two items provide a baseline of what was present prior to clearing the land.

Spatial soil factors related to topography

Soil Erosion can be an oversight during soil sampling. Over time, whether this is due to tillage, water or wind, soil tends to accumulate in lower lying field topography. It can significantly increase soil test values in areas of the field, as the highest testing soil is the first to erode. Soil erosion is one of many reasons why high yielding areas continue to be high yielding.

Even when there is no erosion within the soil profile, water soluble nutrients are moving, and over time accumulating within areas of the field. Some examples of water-soluble nutrients; Nitrogen, Phosphorus, Potassium, Sulphur, Boron, Calcium, Magnesium… wait a minute, what? Yes, to varying degrees all nutrients have a portion that is water-soluble, and regions within the field are incurring losses or accumulating nutrients. Granted there is much more movement of Nitrogen than Phosphorous

Another factor that frequently is not discussed is topsoil depth. This will not show up on a soil test report. A deeper topsoil will have a larger supply than a thin A horizon soil with the same results. Even if the soil tests are both pulled with a 6” core. The purpose of this point is the impact it can have on fertilizer response. Two tests can have the same values yet respond differently.

Spatial soil factors affected by management

Unevenly applied inputs are an example of spatial variability. Examples include uncalibrated equipment, overlaps, or accumulations from banding. With GPS operated equipment, bands could be applied year over year in the same location within the field. Especially in no-till/strip-till fields, where tillage would normally mix the bands with adjacent soil. Also think about fields with drastically different management merged into one larger field, such as when manure was applied to areas close to a barn.

As far as inputs, commercial fertilizer will mainly influence phosphorus and potassium results. Lime can influence calcium and magnesium levels depending on the source. Lime will also influence availability of other nutrients such as manganese, phosphorus, and zinc. Organic amendments such as compost, manure, and non-ag source material can influence both macro and micro-nutrient levels in the soil profile.

When crop residue is removed from the field, or is redistributed unevenly, nutrients are moving with it. When residue is spread unevenly, over time it is accumulating in bands. i.e. a 30’ band of residue from a 40’ harvest width. In extremely low testing fields, the bands start to show up as uneven crop growth and nutrient deficiencies.

Each crop within a crop rotation removes different nutrients at different rates. Crop yield will affect the total amount of fertility removed in various parts of the field. Because of this, the lowest testing soils can be some of the highest yielding areas, due to high removal rates. The highest testing soils can be some of the lowest yielding areas, due to low removal rates.

Temporal Factors

With the cool temperatures and wet conditions in spring 2019 and cold temperatures in spring of 2020, phosphorus, and mobile nutrients such as boron, nitrogen, and sulphur were slow to release from soil organic matter. In Ontario, mobile nutrients are typically not sampled in the fall for the following crop. But it is useful to think big picture about the release of these nutrients, and how you would manage for response the following season.

We discussed water movement within a field, but there is also year to year (temporal) variability of rainfall. This primarily impacts mobile nutrients as they move deeper into the soil profile under higher rainfall.

As you develop your plan for the 2021 growing season, consider the spatial and temporal factors and the impacts they can have on your crop. What factors can you control, and what factors do you have to adjust for?

“It doesn't pay to be logical if everyone else is being logical.”

- Rory Sutherland