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The Cropwalker - Volume 3 Issue 48

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This will be the last 2020 issue. Next issue will be in 2021 after we return from the Ontario Agricultural (SWAC) Conference

We hope you have a Happy Holiday season and can spend time relaxing and enjoying your family (from a distance)

We also thank you for your interest in the Cropwalker. We especially appreciate your positive comments and questions. And we really like it when you give us a different angle to a topic we have addressed.


Forages Reduce Weeds

I made this statement and a reader said you might be partly right but also a couple of big weeds that are a problem in forage fields are still there after 3 years of forages. The reader is correct. These are chickweed (which is particularly bad in Oxford county) and shepherd’s purse. Both of these weeds are broadleaf winter annuals/perennials. Typically forages reduce annual grass populations because a high percentage of annual grass seeds germinate in the first 2-3 years after they arrive in the soil. Forages control perennial weeds by smothering them. Constant cutting does not allow perennial weeds like perennial sow thistle to get established. But annual and winter annual broadleaf weed seeds can survive in the soil for a long time. Below are some examples from the Oregon State University web site.

  • Brome grass seed seldom lasts more than two years.
  • Annual ryegrass - up to nine years.
  • Perennial ryegrass - up to three years.
  • Annual bluegrass - up to about five years.
  • Wild oats - three to six years, but longer in deep soil.
  • Barnyard grass - up to 13 years.
  • Mustards - are long lived. Seeds excavated from a monastery in Denmark were dated to be 600 years old and 11 of them germinated. More commonly, mustard seeds last for decades.
  • Lambs quarters - may last up to four decades.
  • Wild carrot - several years.
  • Curly dock - more than a decade.
  • Common groundsel - most die within a year.

Common chickweed Information from Michigan State University Longevity: Common chickweed seed is moderately persistent because it takes 3 years for the seed bank to be reduced by 50% and about 18 years to deplete the seedbank by 99%. In two studies, 5 and 6 percent of the seeds remained viable after 10 years. Common chickweed is an alternate host for soybean cyst nematode which gives you another reason to control it.

Establishing Forages in fields with common chickweed

One way is to use Harvxtra alfalfa. Spray with Roundup to control chickweed after the alfalfa has emerged. Then seed grasses after spraying glyphosate. Another strategy is to summer seed alfalfa. You can control chickweed with glyphosate before seeding. Then with an aggressive forage management strategy you keep ahead of chickweed. The strategy includes a high forage seeding rate and good fertility.

Controlling Shepherds Purse in New Seedings

Embutox or its generics (2,4-DB/Caliber/Cobutox) will control shepherd’s purse in new seedings. They must be sprayed at the 1-4 trifoliate of alfalfa.

Slugs are hermaphrodite, so every individual can lay eggs - up to 300 each slug. Eggs are laid in batches, usually 10-50, in moist but not waterlogged soil. Most species found in gardens have an annual life cycle lasting less than a year, and lay eggs in any month providing conditions are suitable. In terms of the Control ground beetles are the “lions of the no-till fields”. So, if you use an insecticide to control slugs you will do more damage than good because you control the slug predator “ground beetles”.

Picture 1 - Ground Beetle (source: OMAFRA)

Penn State University Extension

John Tooker, Extension Entomologist with Penn State University Extension, reports on soybeans that were planted into winter rye cover crop. One to seven days later, he burned off the rye with glyphosate. He found that the slugs fed on the dying rye more than they did on the corn and soybeans. He said that dying rye is more attractive to a slug than a growing corn or a growing soybean and thinks it’s because there’s more of an available protein in that dying rye”. “Yet this is also a wonderful habitat for ground beetles and their allies, so the slugs are feeding there away from your cash crop, but they are also getting hammered by the predators. “Slugs are nocturnal herbivores, so they generally feed from dusk to dawn, but they may feed during the day if it is raining. Activity increases with temperatures below 70°F and with higher humidity (they prefer 100% humidity). Slugs can feed when temperatures are as low as 34°F, although their activity is decreased. Activity is also reduced at temperatures greater than 80°F, because slugs are 80% water and are prone to desiccation; therefore, warm, dry conditions slow slug activity while mild, wet conditions promote activity. Significant slug populations are most likely during a wet spring that follows a mild winter, or any spring following a wet fall, because wet soils promote egg-laying.”

Slugs do not move like insects. They will stay where you find them. If you have a bad spot for slugs and you no till you can do a shallow discing in those areas to reduce their numbers. Using aggressive row cleaners to remove residue over the row may reduce damage.

Envita Nitrogen Inoculant for Corn

I have checked further for data validating the use of this product. Dr Tom Bruulsema, Chief Scientist with Plant Nutrition Canada advised that “since several years ago CFIA does not require data submission proving efficacy of the product. The only requirement is data relating to health impact on humans and the environment” In an earlier Cropwalker we outlined how you could put out your own trial on this product. Their ads claim you can reduce your nitrogen rates by 27% by using Envita. The registered ingredients are GLUCONACETOBATER DIAZOTROPHICUS 1x10^7 CFU/ML.

Ontario average yields as published by OMAFRA

These numbers are put together by Stats Canada and in a spirit of cooperation OMAFRA uses Stats Canada numbers. The last couple of years there has been a significant difference in yields reported by Stats Canada and Agricorp. Will update with Agricorp numbers when available (we feel they might be more accurate than the OMAFRA/StatsCan estimates).

Figure 1 - OMAFRA 2020 Estimated Yields and Harvested Acres

Fertilizer Education in small doses – Sulphur (S)

Rather than give a long dissertation on S, here are some small rememberable points.

S does not move from old leaves in the plant as does N. Thus, deficiency shows up on new leaves

S can be released from the soil but since winter wheat needs S early it is best to apply some with first N application.

There are a number of products. The most common are ammonium sulphate which is 20% N and 24% S, liquid ammonium thiosulphate which has 1.3 lbs. N plus ­­­2.8 lbs. S per US gallon. The other main products are MESZ 12% N, 40% P, 10% S (50% as elemental) 1% Zn, gypsum which is about 18% S, Sulphate of Potash (0-0-50-18S) and K-Mag (0-0-22-22S-11Mg).

US Weed Researchers Talk about Weed Control

As I read through all these reports some things are making a common theme and we must listen to.

1.     In soybeans you must use full label rate of a residual herbicide

2.     If using a post emergent program, it is easier to kill weeds at 2-3” than 4-6”

3.     You must rotate and record herbicide groups so you do not use the same groups for problem weeds in different crops.

4.     We have to start looking at non herbicide weed control such as rotation, tillage, weed seed destruction.

Balancing or evening out the soil vs. Crop Response

While recording a presentation for the Ontario Agricultural Conference, one of the speakers in the recording had commented on wanting to balance out their client’s fields using their precision ag methods. This is incorrect thinking. You cannot “balance” out a soil. In this case it was related to soil pH, and identifying soil pH hotspots and using lime to ensure all low pH “hot” or “acid” spots were taken care of. When sampled a few years later post application the result was a nice even map, However, if I am the agronomist making the recommendation, I am not attempting to “balance” out the soil pH for the field, I am recommending lime in those areas because it provides a crop response, not because the field will then be even. This is of particular importance when you have areas within the field at levels that are not responsive to added fertilizer applications, and areas that are highly responsive. For example, if one part of the field has 200 ppm of nitrate on a PSNT test, and another area has 20 ppm. I will not be “balancing” the field to 200 ppm of nitrate to make the field even. I will be making an application in the parts of the field that will respond to added management. Apply for crop response, not to “even” out the field.

Bayer Crop Science – New Cereal Fungicide

You may have seen the ads or a press release for it already, Bayer has received registration for TilMOR, a new fungicide slated to replace Folicur EW. The thought process is that it will provide leaf disease control and suppression of fusarium head blight. What are the actives? Tebuconazole and Prothioconazole. Similar to Prosaro XTR, but at a lower amount of active per acre of Prothioconazole, and no crop safener. In a nutshell I expect it to be a “value priced” Prosaro XTR.

Figure 2 - Rates of Active Ingredients for various Bayer Fungicides

Jonathan’s Fertility Notes/Observations/Collections

At this time fertility planning season has started, time for a few notes.

1.     Understanding Manganese (Mn) – the use of the Mn index can provide an indication of soil manganese supplies. Mn deficiency in soils with amble soil supplies can be caused due to several different factors, usually due to environmental conditions such as dry soil conditions early in the season when plants have a shallow root system. Under these conditions the Mn becomes unavailable.

a.     In these instances, applying a foliar product is paramount to correcting the underlying issue. Because Mn is not mobile within the plant, and does not translocate to new tissue, additional applications of Mn is required should you continue to remain in the same weather patterns causing the Mn deficiency. Typically, if you have a MN deficiency you will need two applications.

b.     You must use a “high load” micronutrient to provide adequate crop response, this usually means applying a single nutrient foliar fertilizer containing Mn.

c.     Certified Crop Advisor Dale Cowan had an excellent article in the November 2020 issue of Better Farming on crop response to foliar applications of Mn. In his trials in his area, he found a 0 to 22 bu/ac response in soybeans, with 75% time getting a 3 to 5 bu/ac response. In winter wheat, in a one-year, one-site trial, they found a 15 bu/ac gain with 8 lbs./ac of MnSO4, 16.1 bu/ac gain with fall (8 lbs. MnSO4) and spring foliar, and 7.7 bu/ac with two spring applications.

d.     If you have visual Mn deficiency, waiting to correct the issue is typically not a great idea. In a crop like soybeans 80% of the Mn uptake is during the vegetative stages. Waiting just encourages the plant to build a smaller factory.

2.     Environmentally Safe Nitrogen (“ESN) – is a polymer coated Urea with an analysis of 44-0-0. It has been on the market for quite a while, but in recent years with strong demand, its price has also crept up (40% more than Urea per lb. of N the last time I had checked). It is just as susceptible to N losses as regular Urea if surface applied to soil or is lightly incorporated and the polymer coating has been broken (i.e., poor product quality) Unless growers require ESN for seed safety purposes in a strip-till or starter application (also improved flowability), I typically recommend splitting nitrogen needs instead, or the use of inhibitor like Agrotain, to minimize N losses.

3.     Pounds of plant available nutrient in the soil

a.     If you took a 6” sample, multiple by two. 10 ppm = 20 lbs. of actual available nutrient.

b.     If you took an 8” sample, multiple by 2.7. 10 ppm = 27 lbs. of actual available nutrient.

c.     If you took a 12” sample, multiple by 4. 10 ppm = 40 lbs. of actual available nutrient.

d.     If you took a 24” sample, multiple by 8. 10 ppm = 80 lbs. of actual available nutrient.

4.     Iron layers in soils can be an indication of a high-water table. If Iron content is high in the ground water, a reddish layer on the wall of the soil pit indicates the high of the water table.

5.     Cation Exchange Capacity – can be used to infer soil type but is not a substitute for soil texture analysis (sand/silt/clay content). The cation exchange capacity is calculated with a few underlying assumptions on how many positively charged nutrients it can hold. A true CEC analysis takes a long time and is costly. The CEC on your soil test is a computer-generated number based on the cations Ca, Mg, K, (and soil buffer pH, if below 7). Organic matter can reflect on CEC, but it is not considered when calculating soils CEC.

Figure 3 - Example CEC Calculation using ppm of Crop Nutrients

6.     Magnesium is the center of the chlorophyll molecule (the part of the plant photosynthesizing, making plant sugar, ATP). This is why when you have Magnesium deficiency, you end up with white leaves (lack of chlorophyll). Ontario CCA Patrick Lynch had a great article in the December issue of Better Farming

a.     Usually, the cheapest way of applying magnesium to the soil is dolomitic lime. K-mag is a good option for starter or broadcast placement, especially in soils also responsive to sulphur and potash. Magnesium Oxysulphate (36% Mg) is a good option as well, but from my experience, it is usually cheaper to use K-Mag due to the sulphur and potassium content.

b.     On low CEC soils, you can have adequate base saturation of magnesium (10%), and still have deficiency (less than 100 ppm). Base saturation provides an indication on the ration of nutrients in soil solution but doesn’t indicate the amount of nutrients present (ppm is required for that).

I have high magnesium soils can I leach out magnesium out of the soil profile?

On soils high in magnesium with low Cation Exchange Capacity, it is possible to leach excess magnesium out of the soil profile (through tile drainage). You will need another cation with a higher affinity than magnesium, to knock Mg off the soil electrons. I question why you would spend money on this practice to and reduce magnesium content, as properly timing tillage or adding a more diverse crop rotation/cover crops is likely to be a more effective approach to dealing with soil structure issues cause by high magnesium levels (less tillage seems to help a lot). From my experience using site specific soil sampling, areas within a field with high magnesium levels usually indicate a depression where water accumulates and does not drain.

"Avoid intense ideologies. Always consider the other side as carefully as your own.”

- Charlie Munger