Can Sidebanded Nitrogen Cause Injury in a Dry Year?

Submitted by: John Heard, Manitoba Agriculture, Soil Fertility Specialist

With a lack of seedbed moisture, there are justified concerns about seedplaced fertilizer injury to canola and other crops.  How safe is sidebanded nitrogen? Research studies by  Dr. Cindy Grant documented considerable canola stand thinning when high rates of sidebanded urea or UAN solution were applied.  Agrotain (AT) served to reduce stand injury, but is no longer supported for this use by the manufacturer. 

Points:
  • Stands were thinned at even modest N rates, on a clay loam soil.  At high rates stands were reduced to 50%
  • Crop growth compensated for reduced stands and generally produced as good a yield as the Agrotain protected stands, except at the highest rate.
For more detailed analysis and discussion on the issue see the full .pdf
More topics on soil fertility can be found on Manitoba Agriculture’s Soil Fertility webpages.
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Seed Placed Fertilizer Cautions for Canola

Submitted by: John Heard, Manitoba Agriculture, Soil Fertility Specialist

Spring 2018 has brought many questions about seedplaced fertilizer rates for canola.  Several factors are causing concern:

  • Drier soils – which increase the risk of seed toxicity
  • Desire to apply sufficient P to meet crop removal – since many fields have seen decreasing P levels due to high yield.  P removal is about 1 lb P2O5/bu, so high yield potential fields are looking at high P replacement rates.
  • Increased use in low disturbance, low seedbed utilization (SBU) drills.  Many new openers are arriving on the scene, which are “close-to-seed” sidebanding for which one may need to consider as seedplaced.
  • Desire by growers to reduce seeding rates for cost savings.  Most research studies investigating seedplaced fertilizer injury were seeded at some 150 seed/m2, about double what some farmers are now targeting.
For more detailed analysis on the issue, see the full text in .pdf format 
 
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How did the cold temperatures affect my winter wheat?

Extremely cold temperatures were experienced throughout Manitoba at the end of December and beginning of January. The cold temperatures combined with limited amounts of snow cover have many winter wheat producers thinking about winter survival.

Manitoba Agriculture’s Ag Weather Program has been monitoring soil temperatures in winter wheat fields for a number of years. There are currently three weather stations measuring real time soil temperatures in winter wheat fields at Alexander, Dauphin, and Kleefeld.  The data collected from the weather stations is made available to the University of Saskatchewan and Western Ag Labs for their Winter Cereal Survival Model, available at: https://www.wheatworkers.ca/wcsm.php.  The Winter Cereal Survival Model compares the cold tolerance of winter wheat varieties to the daily average soil temperature at crown depth (about 1”).

Plotting the soil temperatures against hardiness curves can give an early indication if there is a concern for winter injury or winterkill. Factors that can impact the level of cold hardiness of the plant include weather, fertility, seeding date, and seeding depth.  In Manitoba, the majority of winter wheat acres would likely be considered to be well-hardened.  The figure below shows soil temperatures at 1” depth in three winter wheat fields in Manitoba, plotted against three hardiness curves.

Figure 1. 2017/18 soil temperatures (as of January 16, 2018) measured at 1” depth in three winter wheat fields. Data Source: Manitoba Agriculture Ag Weather Program

Soil temperatures in Alexander and Dauphin dipped below the low hardiness curve, but have not approached the mid and high-hardiness curves at this point. To assess the level of risk on your farm consider how well-hardened your field may be and check your fields for level of snow accumulation.  It is still early in the season, so check back in on the Winter Wheat Survival Model throughout the winter to get an idea of the risk of winterkill in your area.

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

 

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Submitting Grain Samples for Grading

It is important to know the grade and dockage of your grain prior to marketing to ensure that you receive a fair price for your grain. The Canadian Grain Commission (CGC) provides the following grain grading services:

The Canadian Grain Commission’s Harvest Sample Program
The Harvest Sample Program provides unofficial grade and quality results at no charge for most grain, oilseed, and pulse crops.  Samples are submitted at harvest time and results are emailed to the producer.  Producers who have previously signed up for the Harvest Sample Program will receive a Harvest Sample kit annually.  For more information on the Harvest Sample Program or to sign up visit the CGC website.

Producer Request for Inspection Services
Producers that did not participate in the Harvest Sample Program but would still like to receive a grade for their grain can submit a sample to the CGC for a fee.  It is important to submit a representative grain sample as the grade received should accurately represent grain stored in a bin.  Instructions on representative grain sampling can be found on the CGC website.  Once you have a representative sample, complete the request for inspection services form I-106 and send the sample by mail or courier to the CGC Weyburn office for inspection.  Instructions and additional tests available are found on the form.

What steps can be taken when you disagree with an elevator’s assessment of your grain’s grade and dockage?
As legislated under the Canadian Grains Act producers can dispute a licensed primary elevator’s assessment of their grain. If you do not agree with the assessment of your grain at the time of delivery, you can ask that a representative sample of your grain be sent to the CGC for inspection. Payment for your grain will be subject to the inspectors grade and dockage. For more information, visit the dispute your grain grade section of the CGC website.

 

Submitted by Anne Kirk, Cereal Specialist, Manitoba Agriculture

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Considerations for Overwintering Corn

The vast majority of corn in Manitoba is in the bin, but what about those few fields that may not be harvested yet? In some cases weather conditions may have made it difficult for farmers to harvest corn in the fall, but some farmers may decide that the corn moisture level and costs associated with drying mean that it is more economical to leave corn in the field to let it dry down naturally over winter.

Just how much dry down can be expected over winter? The amount of drying that occurs in the field depends on the corn maturity, variety, and moisture content, as well as environmental factors such as temperature, humidity, solar radiation, and wind speed. Field drying is extremely slow in the winter, and corn will only dry to about 20 to 21% moisture content. In a typical year, it is expected that corn will dry approximately 11-12% in October, 4-5% in November, and just 2% per month in December and January (Table 1).      

Table 1. Estimated corn field drying

Month

EMC (%)* GDD PET (in.) Estimated Drying (% pt.)
Month Week
Sept 15 250-350 4-5 18 4.5
Oct 16 100-125 2.8-3.5 11-12 2.5
Nov 19 20-30 0.8-1.2 4-5 1
Dec 20 0 0.5-0.8 2 0.5
Jan 21 0 0.5-0.8 2 0.5
Feb 21 0 0.5-0.9 3 0.8
Mar 19 0 1.3-1.6 5 1
Apr 16 50-90 3.2-4.5 16 4
May 14 200-300 6.5-8.5 30 7

*EMC – equilibrium moisture content, GDD – growing degree days, PET – potential evapotranspiration 1EMC is the moisture content to which corn will dry and is based on air temperature and relative humidity

Source: Ken Hellevang, 2009. 2009 Post-harvest tips for later maturing corn. NDSU Extension Service.

Risks of overwintering corn Heavy snowfall during the winter can cause significant amounts of lodging resulting in yield losses. Root and stalk strength should be taken into consideration when deciding if a field should be overwintered. Research conducted at the University of Wisconsin examined corn yield loss during the winter (Table 2).

This researched showed that in 2000, a year with heavy snow cover, yield loss was much greater than in 2001, a year with very little snow cover.  Standing corn may result in more snow catch and slow soil drying in the spring, which could delay planting.

Table 2. Percent yield loss of corn left standing in the field through winter at Arlington, Wisconsin.

Harvest Month
Year Nov Dec Jan Feb Mar Apr
2000 No Loss 45% 58% 59% 65% 38%
2001 5% 5% 9% 18% 7% 10%
Mean 3% 22% 32% 37% 32% 24%

Source: Schneider and Lauer, 2009. Weight risk of leaving corn stand through winter. UW Extension -Team Grains.  http://corn.agronomy.wisc.edu/Teams/TG001.pdf

Corn can be harvested throughout the winter if conditions are cool and there isn’t much snow. If stalks stay standing throughout the winter, and ear drop and wildlife damage are limited, corn can get through the winter without much yield loss.  Yield loss throughout the winter will vary by hybrid and environmental conditions.

If you are planning to over winter corn please contact your local MASC agent.

Submitted by Anne Kirk, Cereals Specialist, Manitoba Agriculture

 

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Early September Frost – What is Going to Happen to My Soybeans?

September 5, 2017  – Pinawa, Winnipeg, Whiteshell and Steinbach overnight forecasts, Environment Canada is stating there is a risk of frost. 

Whether or not there is yield loss in soybeans depends on two factors.  One is how cold it gets and how hard it freezes.  We won’t know the story on that until tomorrow.  The other factor is the growth stage the soybeans are at and that is determined by examining the pods on the plant.  It is all about the pods, so don’t get distracted by the condition of the leaves.  The more advanced/mature the soybeans pods are, the less the potential yield loss.

Manitoba Pulse and Soybean Growers has a maturity guide on their website that will provide you with excellent pictures and descriptions of the growth stages we are now seeing in our fields.  Use it as your guide in determining where your beans are at.  Click on the link below to access:

http://www.manitobapulse.ca/wp-content/uploads/2015/08/Soybean-MATURITY-GUIDE_Apr-2017_WR.pdf

In terms of yield loss, use the following as a guide:

  •  Frost during the R5 stage can reduce yield by 50%-70%.
  •  Frost at the R6 stage can reduce yield by 20%-30%.
  •  Frost at the R7 stage can reduce yield by only about 5%.
  •  At the R8 stage no yield reductions are expected. Dupont Pioneer has also put together a factsheet on frost damaged soybeans that is helpful  https://www.pioneer.com/home/site/us/agronomy/library/frost-damaged-soybeans/.

You will always find some variation around predictions of yield losses due to frost in soybeans.  This is to be expected.  There is no absolutely right answer.  No crop is uniformly at one growth stage and every frost event is unique in how it plays out.  The information above is merely meant to serve as a guide.

Let’s hope we stay well above zero!!

Submitted by: Terry Buss, Beausejour Farm Production Extension Specialist – Crops, MB Ag and Dennis Lange, Pulse Crop Specialist, MB Ag.

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What Would an Early September Frost Do to My Sunflowers?

September 5, 2017 – Risk of Frost in Pinawa, Winnipeg, Whiteshell and Steinbach tonight……….

Frost anytime before the sunflower crop reaches physiological maturity (R9) can cause damage. Once sunflowers reaches the R7 stage (ray petals have dropped, back of head starting to turn yellow), sunflower can withstand temperatures as low as -4° C, but temperature, duration and crop stage will influence the type and amount of damage.

A killing frost in sunflowers is considered to be -4 to -5° C for 6 or more hours, as this low temperature for the extended period is required to penetrate the thick layer in the back of the sunflower head and start the dry down process.  See attached bulletin for more details:

http://www.gov.mb.ca/agriculture/crops/production/pubs/frost-sunflowers.pdf

Visit www.canadasunflower.com for more updates on all sunflower issues

Visit Manitoba Agriculture http://www.gov.mb.ca/agriculture/crops/ for more frost information for other crop types

Submitted by Anastasia Kubinec, Manager – Crop Industry Development, Manitoba Agriculture

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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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Do you Have Potassium Deficiency?

Several of our maturing crops are now exhibiting deficiency symptoms that are too late to correct, but important to address for next year.
Potassium (K) is often overlooked in much of Manitoba due to our naturally high K levels in clay and clay loam soils.  But deficiencies on lighter textured soils are increasing – particularly with soybeans. 

 

Picture 1: Mild potassium deficiency symptoms on upper leaves in August

Potassium deficiency often shows up during pod and seed fill, since soybeans remove 1.4 lb K2O/ bu of grain, the heaviest rate of removal of any grain crops.  As K is translocated out of leaves to fill seeds, the deficiency shows up as yellowing and later necrosis of the leaf margins.
Sometimes odd strips occur of alternating deficient and normal soybeans occur in fields.  These are often related to a previous canola or cereal swath that has had the K leach out of the swath into the soil beneath, and hence marginally increasing K supply in that strip.
If either of these symptoms are observed, a K deficiency can be readily identified with a traditional soil K test and a recommendation will be made for future K fertilization.

Picture 2: Alternating strips of varying potassium deficiency in maturing soybeans due to previous canola swaths.
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