Don’t Rely Solely on Your Grain Loss Monitor – Estimating Harvest Losses in Cereals

It is harvest time in Manitoba. Since final yields aren’t determined until the crop is in the bin, attention now has to be focused on the harvest operation. Grain loss at harvesting time is a direct loss of income. The more grain saved, the greater the returns. The following information comes from 2 articles: ‘Grain Harvest Losses’ by V. Hofman with edits by Dr. J Wiersma & T. Allrich (University of Minnesota) and ‘Estimating Harvest Loss’ by G. Carlson & D. Clay (South Dakota State University).

Grain harvest losses result from shattering of the standing grain, shattering during windrowing (swathing) or direct combining, picking up the swath with the combine, and threshing, separating and cleaning within the combine. Estimates of acceptable losses for small grains such as wheat, barley and oats are placed at 3% of total yield (total yield equals harvested yield plus harvest losses).

It is usually very difficult to reduce total losses below 1 to 2% so the operator must decide on the value of the crop, the cost of combining and the time available for combining or climate conditions. Some harvest loss is unavoidable in order to get harvesting done in the time available with an end goal of cleaned harvested grain.

Estimating Harvest Losses.  Advancements in engineering have greatly improved harvest operations. Combines have various types of monitoring equipment available, including grain loss monitors, to help alert the operator to any potential problems.  A grain loss monitor is a good guide in selecting travel speed for varying conditions such as size of windrow and moisture conditions. A grain loss monitor must be calibrated to provide an acceptable grain loss reading. If the combine is used on different crops, the monitors are not only useful in limiting maximum speeds and losses, but can be used to properly feed the combine for optimum capacity.

However, a grain loss monitor is not a substitute for careful machine adjustments and good old fashioned monitoring, i.e. getting out of the combine to estimate losses. Or even better, when your local retail agronomist comes out with cold beverages, put him/her to work to estimate harvest losses.

A simple and rough estimate of grain loss requires the use of a one-foot square frame. A rough estimate of how much grain is left behind in a harvested field can be done with a few simple steps:

  1. Pick a typical area of the field after the combine has passed.
  2. Place a 1 ft by 1 ft (inside dimension) box on the ground and count the kernels found within the box. To improve accuracy, three counts (one behind the left side of the header, one behind the centre of the combine, and one behind the right side of the combine) are better.
  3. A one (1) bushel per acre loss equates to 20 wheat kernels/ft2, 14 barley kernels/ft2 and 10 oat kernels/ft2. Keep in mind that this is a ‘fudge factor’ but for the purpose of rough field estimation is an adequate estimate. There are more accurate ways to estimate harvest losses which take into consideration the width of windrower cut and combine cylinder.

If losses are on the high end, some investigation is warranted to try and identify the source of loss.  Is the crop shattering prior to the arrival of the combine (do the above steps before harvest to determine this)? Are there header losses? Or are the losses due to less than perfect threshing/separation of grain within the combine?  Finding the answer may help to adjust the harvest operation and maximize the amount of grain going into the bin!

Good luck with Harvest 2015.

Submitted by: Pam de Rocquigny, Provincial Cereal Crops Specialist, MAFRD

 

Respond
Have a follow-up question?

White heads in wheat, could it be wheat stem maggot?

The following information is available in the Manitoba Insect and Disease Update for the week of July 27th & posted at: http://www.gov.mb.ca/agriculture/crops/seasonal-reports/insect-report-archive/insect-update-2015-07-28.html
White heads of wheat (Figure 1) are noticeable in some fields of wheat that should otherwise have green heads still. One possible cause of this is wheat stem maggot.  If wheat stem maggot is the cause, most of the heads will easily slide out of the stem when you pull on them. And if you slit the stems you may be able to see the pale green maggots inside (Figure 2). They also tend to leave frass in the stem that looks like sawdust. In some of the wheat around Carman the white heads are noticeable, but at such low levels that yield loss would be negligible.
wheat-stem-maggot-damage-jg-carman

Figure 1. White head from wheat stem maggot.

 

wheat-stem-maggot-on-wheat-jg-carman,mb-july23-2015

Figure 2. Larva of wheat stem maggot.

 

This is something that can be very noticeable, because of the way the white heads stand out, but is rarely of economic significance. The are no insecticides registered for wheat stem maggot, nor guidelines for timing an insecticide. So it is worth checking out what is the cause of the white heads, but for wheat stem maggot it is not something to get too alarmed over.
Keep in mind too that there are diseases and environmental factors that can also cause white heads in wheat, so it is not always immediately obvious what the cause is.  More on other causes can be found in the Crop Chatter post “What’s Causing the Bleached Heads in my Wheat Crop?” at http://cropchatter.com/whats-causing-the-bleached-heads-in-my-wheat-crop/
By:  John Gavloski, Entomologist, & Pam de Rocquigny, Provincial Cereal Crops Specialist, MAFRD
Visit the Insect Pages of our MAFRD website at: http://www.gov.mb.ca/agriculture/crops/insects/index.html

 

Respond
Have a follow-up question?

Importance of Preharvest Glyphosate Timing

Modified from Post Originally Published July 30, 2014

Staging a crop for preharvest glyphosate application for weed control can be difficult when there is variability of crop staging within the targeted field.  To go back to the basics, for wheat you want to apply the preharvest glyphosate when grain moisture of the wheat crop is less than 30%.  In terms of visual assessment, the wheat crop must be in the hard dough stage.  This is when the kernel has become firm and hard and a thumbnail impression remains on the seed (see Figure 1).  Remember….you can’t rely on the color of the field as an indicator.  Walk the field and hand thresh heads to determine kernel staging.

Figure 1:  Kernels at various times during grain filling: a) kernel at watery ripe, b) kernel at late milk, c) kernel at soft dough, d) kernel at hard dough showing loss of green color, and e) kernel ripe for harvest.

Source:  Growth and development guide for spring wheat. 1995.  S.R. Simmons, E.A. Oekle & P.M. Anderson.  Photographer:  Dave Hansen.

So what is special about this 30% moisture content?  At the end of the hard dough stage, the kernel has reached its maximum dry weight and the wheat is therefore physiologically mature, i.e. no more weight is added to the grain.  Therefore, final yield has been determined.

If application of a preharvest glyphosate occurs prior to the 30% moisture content, yield can be reduced, along with quality factors such as kernel weight, test weight and protein.  In addition, early application prior to the recommended timing may result in grain with glyphosate levels above maximum residue limits.  This could have implications depending upon target market.

So in timing an application on a variable field, this will be difficult but remember its likely better to apply when majority of the field is at the recommended timing, or even on the later side, than too early.  Also remember that depending on weather conditions, glyphosate can take up to 2 weeks for optimal weed control. However, under hot, dry conditions harvest could commence is as little as 7 days after application.  So keep harvest timing and weather forecasts in mind as well when planning your preharvest application.

Notes: Do not apply to wheat, or any crops, grown for seed.  Not all glyphosate products are registered for preharvest application on all crop species – always refer to individual crop labels for a list of registered uses and crop species. Check with malt barley or milling oat buyers prior to application to confirm acceptance of glyphosate-treated grain.

Submitted by:  Pam de Rocquigny, Provincial Cereal Crops Specialist & Ingrid Kristjanson, MAFRD Farm Production Advisor, Morris, MAFRD

Respond
Have a follow-up question?

Seeing Leaf Tip Necrosis in Your Wheat Fields?

Updated from Archived Crop Chatter post made June 28, 2013

I have received a few reports over the past couple of days where spring wheat are showing symptoms where flag leaf tips are yellowing and necrotic.  Amir Farooq, Farm Production Extension Specialist from Hamiota, submitted this photo from a field in his area.  He noted the symptoms appeared with the warmer temperatures.

Leaf Tip Necrosis in Spring Wheat, 2015 (A. Farooq)

Leaf Tip Necrosis in Spring Wheat, 2015 (A. Farooq)

Manitoba Agriculture’s Crop Diagnostic lab technician has seen similar symptoms in previous seasons when environmental conditions have caused rapid moisture loss from the leaves, i.e. windy weather combined with warm/hot temperatures.   The result is leaf tip burn or necrosis.

Wind and/or high temperature can result in injury of leaf tips of small grains
Credit: Photo Library of Manitoba Agriculture’s Crop Diagnostic Lab Reports (2009)

Leaf tip necrosis normally progresses from the margins of the flag leaf tip and lower leaves should show some signs of it as well. Note that leaf tip burn caused by wind and/or hot temperature injury can appear similar to the damage of contact herbicides, fungal diseases, viral diseases (BYDV), foliar fertilizer burn or soil salinity.  However, with wind and/or hot temperatures, damage is often limited to the newest, just emerging, leaf tips.  Most reports to date in Manitoba indicate symptoms are on the flag leaf.

Symptoms of leaf tip necrosis can also be observed to some extent in all wheat varieties containing the leaf rust resistance gene Lr34.  The leaf tip necrosis can be more pronounced after cooler weather, such as cooler evening temperatures.

The severity of the leaf tip necrosis is dependent on both the variety and the growing conditions during flag leaf emergence and early grainfill and thus some varieties have a tendency to show a lot more leaf tip necrosis than other.

Unfortunately, there is little information reported in the literature whether this type of damage causes any yield losses. However, the remainder of the canopy has a great ability to compensate for this type of physiological damage. In either case, there is nothing producers can do to avoid or alleviate the symptoms.

Submitted by:  Pam de Rocquigny, Provincial Cereal Crops Specialist, Manitoba Agriculture

Source: “Flag Leaf Burning: Hot Weather and Leaf Tip Necrosis in Wheat” by Jochum Wiersma, University of Minnesota

 

Respond
Have a follow-up question?

Historical Seeding in Progress in Manitoba – First Week of May

Producers who participate in AgriInsurance provides seeding date information to Manitoba Agricultural Services Corporation (MASC).  This dataset provides us a historical perspective of when seeding has taken place in the past.  Seeding date data information is broken down into a week:month format, i.e. 1:05 is Week 1 in the 5th Month (May).  So 2:05 is Week 2 in May, and so on.

Each week is then categorized dependent on the day of the week in which the month starts.  So if Week 1 starts on a Sunday, there will be 7 days of seeding captured in Week 1.  However, if Week 1 starts on Friday (like we have in 2015), there are 9 days captured in Week 1.  Confused yet?  Essentially, each year will have a different number of days captured in each weekly timeframe, varying from 5 days up to 12 days.  However, the data still provides good reference points to seeding progress in Manitoba.

In Table 1, cumulative seeding progress to the end of Week 1 in May for six crop types is provided.  The last five year (2009-2013) average cumulative seeding progress is noted, along with what was seeded in the same timeframe in 2014.   Please note that data is for final insured crop in the ground.

Table 1:  Seeding progress (%) in Manitoba by end of Week 1 in May (1:05).

End of Week 1 May Seeding Progress

Based on the May 11th Manitoba Crop Report, overall seeding progress is estimated at 55% complete.  There isn’t a provincial breakdown provided of seeding progress by crop type, but in looking at each region, seeding of spring cereals is ahead of the 5-year average of 2009-2013, and well ahead of 2014!

Submitted by: Pam de Rocquigny, Provincial Cereal Crops Specialist, MAFRD 

Respond
Have a follow-up question?

Should Manitoba growers be worried about the early reports of stripe rust in Alberta?

Submitted by Holly Derksen, MAFRD Field Crop Pathologist

Probably not.

Stripe rust has been reported in winter wheat fields in Alberta this spring (http://www.producer.com/2015/04/stripe-rust-in-alberta-winter-wheat/). This could indicate that the fungus overwintered on the crop. Overwintering of stripe rust in Canada also occurred in 2011, a year where there were measurable losses from stripe rust in both winter and spring wheat in Alberta and parts of Saskatchewan. That year a breakdown in resistance in the 2010 planted winter wheat crop led to higher infections leading into 2011. Persistent snow cover allowed for good overwintering conditions and a cool, wet spring favoured spread and infection of the stripe rust fungus. Growers in Alberta are being encouraged to vigilantly scout for the spread and proliferation of this disease this spring, especially in varieties that do not carry any resistance. Reports from Montana and Oregon have also indicated an early outbreak of stripe rust with fungicide applications being recommended in many cases.

In Manitoba, the majority of our inoculum blows in from the central US states by what is known as the “Puccinia Pathway”. Progress of this inoculum, as well as other cereal rusts, is documented on the USDA’s website (http://www.ars.usda.gov/News/docs.htm?docid=9757). To date, there have been a number of stripe rust detections with the furthest north located near Omaha, Nebraska. There have been no reports of stripe rust in Manitoba, however, inoculum can move quickly so growers should continue to scout their winter wheat and newly emerging spring wheat for early infections. The ideal timing for a fungicide application for protection against stripe rust in wheat is at the flag leaf stage. If rust infections are only noticed later in the year, especially past the flowering stage, a fungicide is likely unwarranted as the yield effect will be minimal.

Respond
Have a follow-up question?

Why are my Wheat Heads Dark?

There have been a number of reports of ripe canola looking black or, in some cases, sooty. We are hearing the same thing in wheat.  So what is the cause?

wheat melanism 005

Wheat affected by melanosis (photo by MAFRD’s Crop Diagnostic Lab)

Holly Derksen, MAFRD’s Field Crops Pathologist, recently did an interview with RealAgriculture.com on the topic of “Black Chaff, Melanosis, Glume Blotch: The Causes of Darkness on Wheat Heads at Harvest“.  Learn more by listening to Holly’s interview with Kelvin Heppner of Real Agriculture.com: http://www.realagriculture.com/2014/08/black-chaff-melanosis-glume-blotch-darkness-wheat-heads-harvest/

Submitted by:  Pam de Rocquigy, Provincial Cereal Crops Specialist, MAFRD

 

 

Respond
Have a follow-up question?

Seeding Date Relationship to Crop Yield

One of our most used extension messages is seed early!

In a year that is later, this may cause some concern that seeding into the second half of May is not going to have good crop yields. Typically seeding earlier does normally translate into higher yields, but good yield potential remains when seeding throughout the month of May, provided you don’t compromise the seeding operation.

Things Other than Seeding Date That Influence Yield:

  • Using clean seed with high %germination
  • Applying the appropriate fertilizer nutrients and rates to support yield goals
  • Seeding for a good plant stand – taking in account TKW, %germination and seed mortality!
  • Seeding into a firm seedbed
  • Seeding into soil warm enough to result in quick germination and emergence
  • Timely weed control
  • Timely fungicide application if needed
  • Appropriate harvest operation timing

2005-13 Seeding Date x Yield

Table 1: Crop Yield Response to Seeding Date (2005-2013)

Source: MASC – Harvested Acreage Report (2005-2013)

For more information see MAFRD website post “Crop Choice Considerations in a Delayed Year”  http://www.gov.mb.ca/agriculture/crops/production/crop-choice-in-delayed-year.html

 

 Contributed byAnastasia Kubinec, MAFRD Oilseed Crop Specialist

 

 

Respond
Have a follow-up question?

What are minimum germination temperatures?

Soil temperature is a useful gauge for timing when crops are seeded.  Table 1 shows the minimum germination temperatures for various crops.  These values should be regarded as approximate since germination depends on several factors.  If the soil is too cool, germination can be delayed which can result in uneven or inadequate seedling emergence.

How do I measure soil temperature?

Determine how deep you will be seeding. Then place your soil thermometer at that targetted depth. Take two measurements throughout the day: one in the morning (8am) and one in the early evening (8pm) . Average the two readings to determine the average soil temperature.

MAFRD recommends that you take readings for two to three days to establish a multiple day average, and reminds you to measure temperature in a number of locations in the field, to account for field variability.  Still not sure, see soil temperature data for various locations across Manitoba is available from MAFRI’s Ag-Weather Program:  http://tgs.gov.mb.ca/climate/SoilTemp.aspx.  This can be used as a guideline for an area, but in-field measurements are going to tell you what is actually going on in your field!

Table 1: Minimum Germination Temperatures for Various Crops

Crop Temperature (°C)
Wheat 4
Barley 3
Oats 5
Corn 10
Canola 5
Flax 9
Sunflower 6
Edible Beans 10
Peas 4
Soybeans 10

Sources: North Dakota StateUniversity Extension Service, Alberta Agriculture & Rural Development and Canola Council of Canada

Respond
Have a follow-up question?

Swath, Desiccate or Let it Be – Field Peas & Cereals?!?

Prepared by Anastasia Kubinec, MAFRI Oilseed Specialist & Pam deRocquigny, MAFRI Cereal Specialist

With the cool, damp weather, crops are not maturing as fast as we would like.  ‘Stagey’ crops, big weeds (ragweed, buckwheat, kochia, redroot pigweed) and risks of weathering impacting quality have resulted in many calls about the differences/benefits of swathing, desiccating or letting the crop be.

First, go look at the crop again – how many stages is the crop at? Is it just low spots that have not turned? If the crop is starting to even up, you may want to leave it with the warmer temperatures coming this week (August 12-19, 2013) and let nature work for you. If the crop is at multiple stages and there are big weeds that will cause combine plugging, swathing, desiccating or pre-harvest weed control is a good management option.  For specific product information, contact the marketing companies for rates and registration details.

Key Notes:

  1.  Swathing or desiccating earlier than recommend (30% seed moisture) will not shorten the maturity of the seed. That is based on genetics and weather.  Performing these activities too early will result in reduced seed yield and quality.
  2. Glyphosate is not a desiccant- it is a pre-harvest herbicide and kills crops and weeds.  Use it for perennial weed control and not to desiccate the crop. Don’t use if crop is for seed use.
  3. Some product MRLs (Maximum Residue Limits) have not been set or are lower than what we can meet for crop export into other countries.  Be aware of marketing restrictions that may arise from using certain desiccants/harvest management tools.  For pulses see www.rayglen.com/pdf/2013%20Desiccant%20Guidelines%20for%20Growers.pdf.  For other crops, talk to you buyers.
  4. Know the weather conditions at application timing that will give the best results – Reglone works better on senescing plants and when temperatures are warm, Glyphosate works better on actively growing plants.

Field pea –Swath when most of the vines/pods are yellow-tan color and you can only barely leave a thumbnail impression. Desiccate when bottom 75% of pods are yellow with seeds firm and rattling in pods.  Desiccation usually eliminates the need for swathing and avoids the issues of wind-blown or rain-soaked swaths, and pick-up losses.  Decision to swath or desiccate will be based on weather forecast for the next 10 days, experience and machinery available.

Winter/Spring Wheat – Swathing timing and desiccation timing is the same – seed at 30% to 35% moisture, or hard dough stage (thumbnail imprint can barely be left in seed). Reglone and HEAT are not registered on any cereal crops for pre-harvest use.  If crop is intended for seed, using  glyphosate is not an option, so swath.  If not for seed and the weather forecast calls for wet conditions for the 10 days, glyphosate may be preferred versus swathing as the crop will weather better standing than in a swath.

Barley/Oat – Check  with your buyer about their policy on desiccants on the crop.  This may make the decision for you.  After determining this, the timing of swathing/desiccant is the same as wheat and the considerations to swath or desiccate are applicable as well.

For malting barley, maltsters want plump, mature kernels. The crop must not be swathed on the green side. Delay swathing until the heads have lost their green colour and have a moisture content of <30%. Swath around green patches to avoid having the sample from the field turned down because of green or immature kernels.   Keep in mind that wet weather may loosen the hull, reducing quality. Straight combining is becoming popular. Standing malt barley suffers less damage from moisture and dries faster. However, this benefit must be balanced against the increased risk of shattering losses. Six-row barley is more prone to shattering and neck-break than two-row barley.

 

Respond
Have a follow-up question?