Soybean Harvest Losses Based on Cutting Height

Prepared by : John Heard, MAFRD Field Crop Nutrition Specialist

There is always incentive to minimize harvest losses.  Here is a graph of measured losses due to improper cutting height in a low podding variety in 2013: Soybean Yield Loss Due to Cutting Height

Make sure you visit your farmer clients as they harvest to do some harvest loss measures.  Determine the average loss per square foot and divide the number of seeds by 4 to estimate bu/ac loss.  Cutter bars cutting stems at 2” will minimize stubble harvest loss.  If the combine operator will not slow down to 3 mph to maintain a low cutting height, then your farmer cannot afford to let them leave so much crop in the field.


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What Should My Soybeans Look like when they are Ready to Harvest?

Prepared by Dennis Lange, MAFRI Farm Production Advisor (Altona)

For new growers knowing when soybeans are ready to harvest can be difficult.  Driving by the field, you may think that it is ready to harvest, but on closer inspection you may find plants that still look yellow to green instead of tan to brown. If your entire field has a greenish tinge or a majority of plants in the field once you walk in look green, your beans would not be ready to harvest.  If there is only a few plants that look like this, you may be ok or this might represent only a low spot or less advanced spot in the field. 

Note the green stem in the group of brown stems


This Field is 5 – 7 days away from harvest (credit: D.Lange, MAFRI)

The soybean plants and pods when mature, should be brown or tan in color and the seeds should rattle in the pod.  When the crop is mature and ready for harvest the seeds would be oval shape and firm.

Seeds on left are ripe and ready to harvest, seeds on right are green and not ready to harvest

Once the combine pulls into the field check the moisture which should be below 13%. The Canadian standard for safe storage is 14% moisture, however soybeans going into the USA require 13% moisture and since a large portion of the soybeans do go into the USA  it best to keep below that 13% level.

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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  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.


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Most of my beans are dry but there are some pods in the field where the seed is still green. What % of green can I have in my sample before it is a concern?

You may be better off to wait a few days before harvesting to allow those beans to mature in the field if it is a high percentage.  

Companies who buy beans say that if the sample  has more than 2.5 % green seed  you could be down- graded.

If however it is just the odd green seed in the sample then it should change in the bin.

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Can You Estimate Soybean Losses By Seeds on the Ground?

Questions have been coming in on the what the number of soybeans on the ground after the combine goes through means for yield loss.  For example, if you have 4 soybean seeds on the ground behind the combine, would that be about a one bushel loss?

In order to get an accurate representation on harvest losses, first you need to establish an area of 10 square feet.  Then within that area, count the soybean seeds on the ground.  Approximately 40 seeds with the 10 square foot area would equal a one bushel loss.

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When Should You Dessicate Sunflowers?

Sunflowers are physiologically mature at the stage R-9. At this stage, the seeds have reached maximum size and bushel weight. Visually, this is when the back of the head is yellow and the bracts are brown. Timing of desiccation is important as application to early can result in decreased seed size and test weight. 

Coverage is also important to increase the speed and consistency of dry-down. Using the water volumes suggested by the manufacturer will provide the good coverage over the back of the heads. In addition to coverage, daytime temperatures above 20-25C  will assist in faster and more effective dry-down of the pulpy tissue in the head and assist in earlier combine operations.

Refer to the Guide to Field Crop Protection for products and rates registered for sunflowers.

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Should I Dessicate My Flax Crop?

Flax can be a frustrating crop to straight-cut combine with the bolls dry and ripe and the stalks still grass green and potentially wrapping around the reel.

The use of a chemical harvest aid or dessicant will not help to ripen flax faster, but is can greatly increase ease of harvest by killing and drying out green stalk material, weeds and can be effective for use in perenial weed control.  If bolls and seed are getting close to maturity, but the stalks green and maybe you have weed issues, dessication may be a very good option.  If you are planning on dessicating, 75-80% of the bolls should be brown.  For product choices and rates refer to the “Guide to Field Crop Protection”. Harvest of flax after application should occur when sample tests dry, typically 7 or more days after application.

If your bolls are mostly still green, please wait a little longer.  As mentioned above, using a chemical harvest aid/dessicant does not speed up seed maturity.  If applying too soon, it can actually reduce yields due to smaller seeds or shriveled seeds that don’t make it into the tank.

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