6 Tips for Winter Wheat Seeding

Canola is coming off and seeding of winter wheat is upon us. While acres of winter wheat have dropped in recent years, there are good agronomic and economic reasons to include winter wheat in your crop rotation.  Get your winter wheat crop off to a great start this fall by considering these seeding tips.

  1. Stubble – Winter wheat needs a good snow cover of 4 inches or more to ensure winter survival. This can be accomplished by direct seeding into tall, dense standing stubble.   Stubble disturbance during harvest and seeding should be minimized to ensure that a good amount of stubble is retained for snow trapping.
  2. Weed control – It is important to control green cereal vegetation prior to seeding winter wheat to eliminate the risk of wheat streak mosaic virus. Winter wheat should not be seeded near immature spring cereals and all cereal volunteers should be controlled at least 2 weeks before seeding winter wheat.
  3. Variety selection – Yield is generally the first factor considered when choosing a winter wheat variety, but farmers should also compare varieties for agronomic factors such as standability, disease resistance, maturity, and winter hardiness. Seed Manitoba is an excellent starting place for evaluating the current and new varieties coming to the marketplace (www.seedmb.ca).
  4. Seeding date – Healthy, vigorous plants must be established before freeze-up to attain maximum cold tolerance. The goal is to have plants with a well-developed crown and about 3 leaves going into the winter. The crown is the area from which the plant regrows in the spring. Research has demonstrated that seeding during the period from late August to early September (approximately August 25 to September 10) consistently produces the best crops in terms of both yield and quality.
  5. Seeding depth – Winter wheat should be seeded less than 1” deep even when seedbeds are dry. Shallow seeding allows the seed to take advantage of fall rains, and as little as 1/3” of rain is enough to successfully establish winter wheat.
  6. Seeding rate – Seed at higher rates to ensure a dense, uniform plant stand to enhance weed competition, winter survival, and yield potential. Typically, farmers should be aiming for a final plant stand of 30 plants per square foot in the fall. Calculate the seeding rate needed to obtain the desired final plant stand with the formula below:

Seeding Rate (lb/ac) = Target plant stand/ft2 X 1000 kernel weight (g) / Expected seedling survival* X 10

*Expected seedling survival is used in its decimal form (90% = 0.9) and includes percent germination and seedling mortality.

 

 

Submitted by: Anne Kirk,  Cereal Crops Specialist, Manitoba Agriculture

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How to Obtain GOOD DATA from Strip Trials…..Use a Calibrated Yield Monitor…

In 2016, some of  John Heard’s corn nitrogen plots yielded over 200 bu/ac with the University of Manitoba plot combine.  He refused to report such astounding yields until the electronic weighing system had been verified with bagged and weighed yields. 

Likewise scrutiny and calibration is required when using yield monitors for strip trial tests.  In 2016 Manitoba Agriculture and Manitoba Wheat and Barley Growers Association compared harvest weights from strip trial yields in on-farm-tests looking at nitrogen and wheat protein.   Several farms had scaled grain carts in addition to their combine yield monitor (Figure 1) and all plots were measured with a weigh wagon.  Figures 2 and 3 shows the trends of grain cart and yield monitor data versus the weigh wagon yield (solid line).

Figure 1.  Comparing yield measuring systems – combine yield monitor, scaled grain cart and weigh wagon.

Farm A – with scaled grain cart used to calibrate yield monitor.  Yields follow trend of weigh wagon weights and are within 2 bu/ac.

Farm B – A seldom calibrated yield monitor with yields not corresponding to weigh wagon weights and up to 6 bu/ac less.
Yields from a perfectly calibrated yield monitor and grain cart would fall on the black line in the graphs above.  Farmers with accurate, scaled grain carts were usually calibrating their yield monitors in each field and producing very similar results as the weigh wagon (such as Farm A).  Those that were calibrated on earlier fields or earlier in the season were unable to measure the subtle yield differences in this study and may lead to erroneous conclusions.
So if yield monitors are being used to measure strip trial yields, I encourage growers to calibrate often with their scaled grain carts or a weigh wagon if available.  The measurements we made were in dry wheat but if crop strips are of varying moisture content, more frequent calibration may be warranted.
The study of the 8 farms comparing weighing systems is available at: http://www.mbwheatandbarley.ca/wp-content/uploads/2014/11/OFT-summary-2017-FINAL.pdf
Submitted by: John Heard, Manitoba Agriculture Crop Nutrition Specialist
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It’s Probably Not Giant Hogweed

Because of our experience with crops and weeds, it’s no surprise that the general public often turns to agronomists for plant identification and management advice. And it’s usually about this time of year – when Ontario puts out giant hogweed advisories and big white umbels are in bloom across Manitoba – that these calls start to pour in.

Cow Parsnip

Fortunately, it’s probably not giant hogweed (Heracleum mantegazzianum) since that invasive species has yet to be found in our province.  It’s more likely another member of the carrot family – cow parsnip (Heracleum maximum).  Unlike its giant cousin, cow parsnip is native to Manitoba and non-invasive.  It’s also very attractive to pollinators.

But even though it’s probably not giant hogweed, it’s still best not to touch it. Because, much like its giant cousin, the sap of cow parsnip may cause dermatitis when in contact with exposed skin.  Symptoms include photosensitivity, a rash and/or blisters.  Reactions to cow parsnip sap are generally much less severe than those to giant hogweed sap.

Information on identification of cow parsnip and giant hogweed is available from Manitoba Agriculture.

 

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Post Anthesis Nitrogen for Wheat Protein

When wheat prices and protein premiums/discounts are high, there is renewed grower interest in late N applications to enhance wheat protein. Following is an old recipe we have recently evaluated in on-farm-tests and small plot studies.

  1. Apply 30 lb N/ac, which is 10 US gallons of UAN solution (28-0-0) diluted with 10 gallons water
  2. Apply with flat fan nozzles
  3. Apply 7-10 days following anthesis (so about 7-10 days after your fusarium head blight fungicide)
  4. Apply in morning or evening when temperatures are less than 20o C. Avoid heat of the day.

Under such treatments we have observed leaf burn of 8-15% of the leaf area without detrimental impact on yield. The one instance sprayed at mid day in high temperatures reduced yields by  6 bu/ac with 31% leaf damage . Protein increase ranged from 0-1.5% and averages are reported in Table 1.

Table 1. Effect of post anthesis N (PAN) on wheat class yield and protein (2015-16).

  CNHR (6 sites) CWRS (7 sites) CPS (2 sites)
Yield bu/ac
Base N 80 68 69
Base N & PAN 78 68 65
Protein %
Base N 13.0 14.2 13.8
Base N & PAN 13.6 14.6 14.1

 

In most cases, the farmer’s base rate of N was high at 150-200 lb N/ac (soil N plus fertilizer), so the extra N was not required for high protein.

The full on-farm-test report is available from the Manitoba Wheat and Barley Growers Association at: http://www.mbwheatandbarley.ca/wp-content/uploads/2014/11/OFT-summary-2017-FINAL.pdf

If attempting such a practice, leave a check strip – not so much for yield determination, but to gauge the success in protein increase.

 

 

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Manitoba Weed Update

Despite rainy and windy conditions, early post-emergent herbicide applications are nearing completion in most crops. Emergence of cool season annual weeds was relatively unaffected by earlier cool, dry conditions while emergence of warm season annual weeds was delayed, resulting in herbicide staging issues for some producers.  Emergence of warm season annuals, like redroot pigweed and barnyard grass, is now well underway due to recent rainfall.

Weed Identification:

Weed identification form: www.gov.mb.ca/agriculture/crops/crop-diagnostic-services/.  Weeds submitted to Manitoba Agriculture for identification in the previous week include:

Black nightshade:

Black nightshade (Solanum nigrum) is a warm season annual problematic in potato, dry bean and soybean production.  What to look for: small seedlings with pointed ovate cotyledons, currently in the cotyledon to early true leaf stage (see picture submitted to MB Ag).

Galinsoga species:

Hairy galinsoga (Galinsoga quadriradiata) and smallflower galinsoga (Galinsoga parviflora) are annual species also referred to as ‘quickweed’ based on their ability to set seed within only weeks after emerging.  What to look for: toothed, opposite leaves and ‘club’ shaped cotyledons (see picture submitted to MB Ag).

Oak-leaved goosefoot:

Of the various goosefoot species coming in for identification, oak-leaved goosefoot (Chenopodium glaucum) has been the most common.  What to look for: goosefoot shaped leaf, often with distinct yellow-green veins.  Stems may be red and green to red.  Typically grows more prostrate than lamb’s-quarters.  Oak-leaved goosefoot does especially well in wet and/or saline areas.

Weed Management Issues:

Manitoba Agriculture staff have begun to receive herbicide drift complaints and are providing advice accordingly. Talking to the applicator should always be the first step in a suspected drift incident.  Herbicides involved in the drift complaints to date include glyphosate, group 2 and group 4 herbicides.

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Why is my Corn Purple?

Many Manitoba corn fields are showing some degree of leaf purpling this spring. Here’s a quick look at why leaves turn purple and what possible causes may be.

 

Leaf purpling is a sign of stress. The leaves are actively producing photosynthates (sugars) but conditions are not allowing normal sugar metabolism or translocation in the plant.  The purple anthocyanin pigment is associated with this sugar buildup in leaf tissue.  The amount of purpling is genetically controlled, so hybrids with more of the purpling genes will appear worse than others, even though all suffer the same stress.

Common stress conditions triggering this purpling are:

  • Warm sunny days but cool nights (4-10oC) – this allows sugar buildup but not metabolism
  • Restricted root growth and development – soil compaction (Figure 1), herbicide injury (such as Edge carryover- Figure 2), standing water.
  • Impaired phosphorus uptake due to insufficient soil phosphorus, lack of phosphorus starter fertilizer (Figure 3) or following non-mycorrhizal crops like canola.
  • Physical injury – recently wind has crimped leaf tips (Figure 4) causing sugars to buildup without being translocated to other growing parts of the plant

Purpling will often dissipate with warmer days and nights and yield loss is slight if any. But severe purpling is a symptom of crop stress, so the astute crop advisor or farmer will exploit it as a visual signal and will investigate the cause so to manage better next year.

 

 

 

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Don’t Overlook Group 2 Herbicide Resistance

You’ve probably read about media dubbed ‘superweeds’ like glyphosate-resistant palmer amaranth and giant ragweed. Glyphosate-resistant weeds often earn this distinction because they are viewed as a greater management hardship for producers than weeds resistant to other herbicide mechanisms of actions (MOAs).  And maybe rightly so.  Farmers dealing with glyphosate resistant weeds elsewhere in the world have been reduced to tillage and hand rouging for weed control in some crops.

But, while glyphosate use dominates the Roundup Ready corn, soybean and/or cotton rotation in the US, group 2 herbicides play an (equally?) important role in our more diversified cropping system. For example, group 2 herbicides are used in crops like alfalfa, corn, dry beans, field pea, potato, soybean, sunflower, and in Clearfield and other group 2-tolerant crops.  These herbicides are also a popular choice for group 1-resistant grassy weed control in cereals.

The point of this article isn’t to downplay the importance of glyphosate resistance but to elevate consideration of group 2 resistance. In Manitoba, over 10 weed species are known to have biotypes resistant to group 2 herbicides.  And herbicide-resistant weed surveys led by AAFC indicate that the prevalence of certain species is increasing (Figure 1).

Figure 1: Prevalence of group 2 resistance in Manitoba in 2003 and 2008 as a percent of the weed species population surveyed (Beckie et al).

 

The following practices can help reduce the risk of developing herbicide resistant weeds and/or managing existing resistant weed populations:

  • Diversifying your crop rotation;
  • Using multiple herbicide MOAs effective on target weeds (e.g. herbicide ‘layering’, tank mixing);
  • Practising good basic agronomy (variety selection, seeding rates, etc.);
  • Judicial use of tillage.

If you suspect group 2 resistance in a weed species on your farm, it’s best to verify this by herbicide-resistance testing. Unfortunately there‘s no quick method – seed from the suspect population needs to be allowed to mature and collected.  Samples can be submitted to AgQuest for testing in Manitoba.

In my opinion, knowing if you have group 2 resistance and assessing your risk factors is worth it. Because while glyphosate resistance is grabbing headlines, group 2 resistance may be quietly growing in your fields.

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Fusarium Head Blight Risk Maps – Now Available for 2017

Winter wheat in Manitoba is nearing or at the heading stage, so it’s time again for the MB Ag FHB Risk Maps.

The first FHB Risk Map of the season was posted June 7, 2017 posted on the Manitoba Agriculture website: http://www.gov.mb.ca/agriculture/crops/seasonal-reports/fusarium-head-blight-report.html.

The maps shows the current risk of FHB based on the last 7 days of temperature and precipitation data gathered from the provincial weather stations. Beginning June 15th (after 7 maps have been created), there will also be an animated map showing how risk has varied over the last week.

The optimal fungicide timing for suppression of FHB is at early anthesis. These maps serve as a guide, but it is important to scout individual fields as local conditions can vary greatly and infection depends on the crop being at the susceptible stage (flowering).

Maps will be updated daily (Monday to Friday) from now until the end of the flowering period for spring wheat in the province. Please check the website for updated maps as there will not be daily email reminders.

 

 

What is Waterpod?

Waterpod is:

  1. an annual weed occasionally found in agricultural fields;
  2. a mobile irrigation system; or
  3. a one person submarine?

 

 

If you chose a), you’d be right. Waterpod (Ellisia nyctelea L.) is an annual broadleaf plant native to Manitoba.  It’s often found in shaded, wooded areas but can also thrive in ditches and agricultural fields.  Our wet soils and cool spring must have provided ideal conditions for waterpod emergence as it’s being found in abundance in fields across the province.

The good news is waterpod isn’t much of agricultural pest.  Although it’s an annual, it emerges and flowers early and usually dies off in June.  It’s also very susceptible to glyphosate and most other burn-off and post-emergent herbicides.

Identifying characteristics:

  • oval cotyledons with a flat top;
  • deeply lobed and hairy leaves;
  • small, white 5-petaled flowers.

 

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How Can I Reduce Fertilizer Losses in Dry Spring Soils?

Dry spring weather is great for seeding but may play havoc with some fertilizer applications and losses.

1.Seedplaced fertilizer – Where seedbed moisture is low or when weather is hot and windy, reduce the rates of seedplaced nitrogen  by approximately 50 per cent. Table 7 of the Manitoba Soil Fertility Guide  http://www.gov.mb.ca/agriculture/crops/soil-fertility/soil-fertility-guide/nitrogen.html indicates safe rates of seedplaced urea under different soil texture, moisture and seedbed utilization conditions.  But as conditions dry, these rates should be reduced accordingly.

2.Surface applied urea or urea-forms (like UAN solution 28-0-0) – are vulnerable to volatilization losses.  The soil and environmental factors increasing risk of loss are well known and include:moist soil conditions, followed by rapid drying

  • high wind velocity
  • warm soil temperatures
  • high soil pH (> pH 7.5)
  • high lime content in surface soil
  • coarse soil texture (sandy)
  • low organic matter content
  • high amount of surface residue (Zero Till)

Volatilization losses can be reduced with dribble placement of UAN versus broadcast applications and the use of an urease inhibitor.  The active ingredient NBPT used in Agrotain Ultra is now marketed by a number of companies.  To expect the same level of protection as Agrotain Ultra, ensure the application rate is similar, since formulation strength and recommended rates differ among suppliers.  Agrotain Ultra contains 27% NBPT with an application rate of 3.1 l/tonne urea or 1.6 l/tonne UAN.

3. Last year the lack of rainfall through much of May left surface applied nitrogen stranded at the surface.  If possible, a portion of the crops nitrogen for cereals and canola should be in-soil placed.  In season applications should be targeted prior to stem elongation of cereals and bolting of canola.

 

 

 

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