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The Cropwalker - Volume 3 Issue 33

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Crop Conditions

Corn earliest is well dented. All indications are pointing to an early harvest. Some chatter that yields will be down because of fewer cobs. But this is offset by more kernels per ear and current weather will give us a higher weight per kernel. (TKW) This is different from bushel weight, but bushel weight should be good as well. Soybeans earliest fields are really starting to turn. Still checking for insect feeding, I’m seeing pod feeding from bean leaf beetle, especially in fields without insecticide seed treatment. Keep check for bugs. Forages not too much activity. Some later harvest of third cut. Recent rains are really helping yields of next cut. See last issue for pre-harvest on soybeans and edible beans. http://newsletter.fieldwalker.ca/issues/the-cropwalker-volume-3-issue-32-273219


Top things to do this week

1.     Check cover crops. If light green, consider spreading nitrogen and sulphur. Check oats for rust.

2.    Check any plots you must make sure treatments you put out are there. Mark them so when you come with the combine it is easy to keep results even.

3.    Do a yield estimate on corn. Check populations vs ear count. Figure out why you have a spread.

4.    Calculate wheat seeding rate and the appropriate drill setting.

5.    Plan an end of the summer get together for anyone going back to school and not staying at home.

Winter Wheat Seeding Rates – The table below is for thinking about. The Ontario Cereal Trials are seeded at 400 seeds/m2. That, theoretically, gives 22 seeds/foot of row (7-inch rows), With 85% germination, that is a theoretical stand of 18.7 plants/foot (never happens). Note: In the spring we believe that any stand with 7-8 plants/foot of row is good enough to keep. The table shows the theoretical lowest seeding rate you could go to and the resulting stand. We over-seed soybeans to get a final stand. Seed soybeans at 200,000 to get 140,000 viable plants. We over-seed wheat to a greater level to get a good stand. When reducing seeding rates, the plant compensates by producing more tillers. These tillers will pollinate later than the main stem. When you reduce seeding rate significantly, you increase the probability of Fusarium since you lengthen the pollination time. We notice that often stands are thin where compaction is an issue. Consider double seeding any areas where there is compaction such as the headland where there was a lot of traffic.

Figure 1 - Wheat Population by Seeds/Plants per Foot of Row Width

More on Wheat Seed Rates

My observation is that most producers are not seeding heavy enough when it comes to wheat seed rates. Mainly due to the fact that most are using “optimal” rates for “optimal dates”, perhaps that happens this year, but most years a good chunk of the wheat goes in a week or a few weeks following the optimal time to be seeding winter wheat. The other aspect is that 30-40% of the field has a higher seed mortality than the best areas of the field, these areas are the ones you end up pulling the plug on due to poor stands. Third, if you are using farm saved seed, what is your true seed cost to bump up the rate, small in the big scheme.

What do you Need in a Wheat Starter? – The controversy used to be liquid or dry or none. Now most acres get a starter. I believe we are getting a more noticeable response to P now since high yields have lower available P as measured by a soil test. The lower the soil P test the bigger the response from a seed placed starter fertilizer.  Growers using liquid are broadcasting either in the previous crop or before planting. Dry starters work just as well as liquid starters. A good starter should have 20-30 lb./ac nitrogen. You could broadcast some of this. The safe rate of Urea nitrogen fertilizer with the seed is 15 lb./ac actual nitrogen. (30 N + K with the seed). You can safely use ESN to increase the rate of nitrogen without burning wheat seed. As you plant later, nitrogen is more helpful to get top growth before entering winter. Phosphorous is a main ingredient in wheat starters. That is because wheat, relative to other crops, needs more phosphorous early, due to growing in cooler temperatures, with reduced phosphorus availability. The response to phosphorous will depend on soil test levels, with lower testing soils having a higher probability of response. There is little Ontario specific research to validate a response to potash in a wheat starter. Potash requirements can be broadcast on the crop before planting or with nitrogen in the spring. Most discussions presume that a starter fertilizer must be seed placed. You can also broadcast your starter fertilizer. It may not give as consistent a response as seed placed but is better than no starter fertilizer. If you normally broadcast P and K for soybeans and wheat before you plant soybeans but did not this spring, consider broadcasting before you plant wheat. If you are broadcasting P and K consider 20-30 lb./ac of nitrogen with that broadcast. Normally, we reduce the spring nitrogen rate by 50% of fall applied nitrogen.

Question Why should I add nitrogen to a winter wheat starter of if broadcasting phosphorous for forages?

Answer Nitrogen helps plants to take up phosphorous. If you are depending on P for starter effect in wheat or forages you should apply N as well. Especially on low testing soils.

Combining Soybeans for Best Wheat Planting –Notes from Phil Needham Wheat Guru from Kentucky. Kentucky is a dryland wheat production area, but a lot of his ideas hold true for Ontario conditions. 1) Spread your soybean straw and chaff as uniformly as possible. Fundamental for wheat planting. 2) Setup chopper on combine to cut into 4-inch pieces. A longer piece will have more momentum to make it out 20+ ft from center and still be manageable for a drill. 3) Large blade on opener does not cut as well as a smaller disk. The smaller disk attacks ground/trash at a sharper angle which allows it to cut better and not ride out. 4) Sloppy seed tubes give poor gravity flow, causing bunching and poor seed distribution. 6) Tracks on combine, tractor, grain buggy causes less compaction and give you a more even seedbed. 7) Controlled traffic is very worthwhile. 8) In Kentucky, 25 units total of urea, potash, sulphur, and chloride seed placed is max for safe rates. 9) Seed placed phosphorous is a must. Potash not likely needed with 80+ ppm soil test. 10) 1.5 million seeds/acre is ideal up to Oct 10, then add 10% each week after. For lower CHU areas the 1.5 Million seeds probably should be 1.8 million seeds.

Question Can I apply sulphur and boron this fall to me alfalfa fields?

Answer No. While there is no research on this question the consensus is that both nutrients are soluble and may be lost before next season when they are needed. Better to put them on next spring. Exceptions would be if you are using Mosaic’s Aspire, a boron impregnated potash, which has two forms of boron, water soluble and a slow release portion. Or the use of Elemental Sulphur.

Soil test analysis are taking longer Due to COVID there is more training required for hires at labs. There is about 50 hours of training required to hire a person to work in a lab. This will not work to hire seasonal staff for a few weeks. And there are a lot more fields being sampled this year. Wheat harvest was early and good so there is more interest in sampling.

Want more Cover Crop?

Best way is to fertilize. All plants do better with fertility. If you want more top growth and thus more root mass, consider applying fertilizer. Most non legumes will respond with 40 or so actual N and I would apply up to 10 lbs. actual sulphur. If you are in an area with extreme drought, may not require any additional N, under the assumption you are not planning to harvest for feed.

What is the Pre-Harvest Interval for Various Fungicides on Oats for Green chop?

According to various labels – Acapela – 7 days; Caramba – 30 days; Folicur; 6 days; Headline AMP – 30 days; Prosaro – 6 days; Tilt @ 0.1 L/ac– 7 days; Trivapro – 30 days.

Using something not listed? Please check the label, look for the words forage or green chop when looking at PHI under the cereals section. Many of the products are only registered for 1 application prior to cutting.

How important is not cutting alfalfa during the “Critical Harvest Period”?

Answer. Not that critical. Research in the 60’s suggested it was important. Now not so much now. However, not cutting during a critical harvest period is more important in older stands, stands with low potassium soil test levels, stands that did not flower at least once this year. But if you are short of feed take the cut. If you really do not need the feed and cannot sell it do not cut. You do not have to worry about alfalfa smothering itself if not cut. Grassy stands or stands with volunteer cereals could lodge and smother alfalfa. The map below shows the start date of Critical Harvest Period. Theoretically you should not cut for the 6-week period after these dates. But the dates change each year. The dates are set as when weather will be too cold for alfalfa to start to regrow.

Figure 2 - Critical Harvest Date in Alfalfa (OMAFRA)

“The man who grasps principles can successfully handle his own methods. The man who tries methods, ignoring principles, is sure to have trouble.”

Harrington Emerson

The reason I share this quote is that I see growers looking at what many are calling “Regenerative Agriculture”. While I think those touting the benefits have a good handle on the issues that need to be addressed, the methods many are suggesting for solving the issues leave much to be desired. If you decide to take the path less travelled when it comes to production agriculture, and by all means, we can’t all do the same thing, take the time to understand crop physiology principals prior to applying suggested methods on a large acreage base.

Going to No-till Winter Wheat from Alfalfa

Ideally you will have sprayed it off prior to making the last cut. If not do it as soon as you have enough acceptable top growth. My recommendation is to do 1.33 L/ac of a 540 gr/ac glyphosate Follow up in the fall with 100 mL/ac of Lontrel XC if you have alfalfa escapes. FYI, you cannot apply Lontrel for preharvest alfalfa, only glyphosate. If there is a lot of grass in the field, you are setting up for Take all since the disease affects grasses and wheat.

Pre-Harvest Weed Seed Viability

“Growers should be cautious when weighing the benefits of late-season herbicide treatments. While these treatments may improve harvest efficiency in many situations, the benefit in reducing weed seed production will be highly variable. If weeds have entered the seed filling stage when the herbicide is applied, it is likely that the majority of seeds produced by these plants will retain their viability. “– Bob Hartzler, Iowa State University


Waterhemp by Numbers

The link to the IL Soy Advisor article speaks to how in one year you can go from having 1 waterhemp plant per acre to an uncontrollable mess in a hurry. I ran the numbers Eric had put in the article and put them in the charts below. What I wanted to point out is that it is highly critical that you a) remove any Waterhemp plants you see in the field if only a handful, and b) use an effective pre-emerge to keep the population that does escape manageable. Eric had assumed you would have 99% control post-emerge, I do not think this is realistic, as the first year you are unlikely to realize it is glyphosate resistant. There are reports of waterhemp weeds seeds showing up in cover crop mixes from the US.


Figure 3 - Pre-Emerge 60% Effective on Waterhemp
Figure 4 - Pre-Emerge 80% Effective on Waterhemp

Effect of Management on Weed Seed Bank 1 of 2

A few questions over the summer on tillage practices and what it takes to reduce weed seed population. Use of herbicides is only one management tool to reduce weed seed populations. Other management practices include; prevention (wash equipment or minimize travel in irrigation water, grazing animals etc.); reduction through seeding rate, ensuring field margins do not have weeds, mowing; seed longevity, leave weed seeds on soil surface for predation; rotation causes shifts in weed species composition. Manure should be composted to reduce weed seed inputs. (Our experience is that composting manure can be variable is controlling weed seeds, temperatures high enough to kill weed seeds also run the risk of the pile catching on fire.) Graph source: https://store.msuextension.org/publications/AgandNaturalResources/MT200808AG.pdf

Variable Rate is a Meaningless Term

In my opinion the precision, fertility and/or consulting industry needs to new term to define making site specific recommendations. The term variable rate is great when it comes to describing the infinite speeds the hydraulic or electric motor can run at applying crop inputs but does nothing to describe or infer confidence the underlying recommendation. The entire premise of applying different rates within fields in the first place is to adjust for different response curves, whether that is seeding rate, NPK or lime. Optimum rate is my suggestion.

Figure 5 - Years required by weed species to reduce viable seed bank
Figure 6 - Weed Seed Distribution by tillage method and soil type

Forage Fertility Pictures and Expected Yield Response – Volume 2/3

I recently completed a presentation on forage fertility, specifically around alfalfa, and felt this is a good spot to share it. Will have 2 nutrients each week for the next 3 weeks. This week, sulphur and boron.

One of the biggest differences between forages and grain crops is the crop response to nutrients like sulphur and boron. Part of the reason alfalfa or grasses is highly responsive to sulphur, is that soil supplies are unable to meet early season uptake rates for these crops, due to temporal effects and/or size of the pool. For boron, alfalfa has regrowth multiple times throughout the season, without this critical micronutrient, it is unable to regrow where it is limiting. See nutrient specific info below.  All pictures sourced from IPNI Crop Nutrient Deficiency Photo Database


Research done in Ontario by U of G’s Dr. John Lauzon and OMAFRA’s Dr. Bonnie Ball found that you could increase your first cut yields by 50% on responsive fields and increase third cut by 100% on the same fields. All the increase was due to increase in alfalfa growth.  In fields where sulphur is severely limited, you may see a crude protein increase as well. Not all fields in the study showed a response, however those that did had a statistically significant and economic response.

Picture 1 - IPNI - Sulphur Deficient Alfalfa on Right
Picture 2 - IPNI - Sulphur Deficient Wheat
Picture 3 - IPNI - Sulphur Deficient Wheat


Response to boron is likely to be variable, given soil type, soil pH, manure history and topography position play into the response rate. Typically shows up in dry weather conditions when boron is unable to mineralize from soil organic matter, and the plant pulls water from lower in the soil profile where boron concentration is low. OMAFRA data suggests that you would get a 1000 lb./ac dry matter response in alfalfa by applying boron to soils that are responsive. In my opinion this number maybe on the low side, see image below for comparison purposes. If hay is $0.04 /lb., boron products are about $10/ac, looking at 4 to 1 return on areas that are responsive.

Picture 4 - IPNI - Boron Deficient Alfalfa
Picture 5 - IPNI - Boron Deficient Alfalfa
Picture 6 - U of W - Alfalfa Management Guide - Boron Deficient Alfalfa

“Extraordinary claims should require extraordinary evidence to be believed."

- Kevin Kelly