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Minimizing Seed Loss at Harvest

Friday, August 21, 2020
filed under: Harvest/Storage

Editor’s Note: Seed loss during the sunflower harvest cannot be eliminated completely.  But it can be reduced — a little or a lot — with astute management.  With that in mind, we spoke with four veteran Northern Plains sunflower producers about the steps they take to keep harvest seed loss at an “acceptable” level.  

These four producers are all current or former National Sunflower Association board presidents.  They include:  Tom Young of Onida in central South Dakota, former NSA president; Clark Coleman of Bismarck in central North Dakota, current NSA president; Scott Nelson of Lakota in northeastern North Dakota, current NSA board member and former president; and Kevin Capistran of Crookston in northwestern Minnesota, current board member and former NSA president.

Here are the questions we asked of them and their responses.
What combine model do you use with sunflower and what header attachment?  Also, do you raise oil sunflower, confections — or both?

Young — A John Deere S670 with a Fantini 12-row header and 30” pans.  We produce both oil and confection sunflower.

Coleman — We run a Deere 9870 combine and JD 930 rigid header with Lucke 9” pans. This year, we have both oils and confections.

Nelson — Our combine is a John Deere S780, and we use a JD 853A eight-row 30” all-crop header.  We produce both oils and confections.

Capistran — A Claas Lexion 760 with a 30-foot CAT G30 and SeedEater 9” pans and reel. We grow oil sunflower for the dehull market.
What are your basic settings when starting to harvest sunflower — and, as well, some typical adjustments you’ll make as you proceed?

Young — We’ve installed an extra clean-out bar on the rotor to push stalks out for any crop with slow rotor speeds.  We’ve also installed a pre-chaffer that can be closed down in front of the normal chaffer.  Beyond that, we go with the standard settings for feeder house, crop diverter, etc.  In dry conditions the feeder chain will do the threshing.  

For oil-type sunflower, our settings run: rotor, 300; clearance, 15-30; fan: 800; chaffer, 15; sieve, 8.  Watch the return elevator and keep it about half full of capacity.  If the sample looks clean and the return is full, may need to slow down or put more trash in the tank.

For confections, the standard settings are: rotor, 250; cylinder clearance, 30; fan, 800; chaffer, 10 – and, bottom sieve at 14.  (Yes, those are reversed compared to when harvesting oils!)

Coleman — We usually start with the owner’s manual recommendations and adjust according to test weight and moisture.

Nelson — We run pretty close to what the operator’s manual states.

Capistran — Our concave clearance starts out at 25mm.  We’ll increase that if the heads are getting busted up; decrease it if seeds are being left in the head and the issue can’t be fixed with more cylinder speed.  Our standard cylinder speed is 500.  That gets increased if seeds are being left in the head, or decreased if we’re hulling out very many seeds.

The sunflower kit from Claas is installed on the cylinder and impeller to help stalks from bridging between rotors.

Rotor speed is around 600.  We start with the front-half rotor covers engaged.  Rotor covers seem to have more effect than rotor speed when it comes to reducing MOG (material other than grain) on the sieve.  Closing the second half of the covers can help with overloading the shoe.

We run the cleaning fan at 1,200 rpm.  Less if you can’t stand seeing any seeds on the ground; more if you want to blow the unfilled seeds out the back (higher test weight).
I have an adjustable airfoil top and bottom sieve (called TM-6) in my machine.  I probably give up a little capacity versus a deep-tooth corn sieve, but I think it can make for a cleaner sample (we average less than 1.5% FM).  I’ll start out at 15mm on top and 12mm bottom; but in really wet ’flowers (like we had last year), I open the bottom completely.
What is your standard ground speed in “normal” harvesting conditions?
Young — We go slower to keep engine heat down.  Try to keep the KW at 80%.  (Deere has a KW output gauge.)  Speed is usually less than 4 mph.

Coleman — We try for around 4 mph.

Nelson — 7 mph.

Capistran — 3.5 to 5 mph.
What’s your preferred seed moisture?

Young — Around 11-12%.  If it is an early fall and air drying is possible, maybe 13-14%

Coleman — Ideally, 11-12% and then go to air bins.  Going a little wetter helps with combine fires.  When we get down to 9% or lower, we start seeing fires.

Nelson — We like to go at about 15%.

Capistran — I’d love to start at 10% and just bin them, but the last few years we’ve taken off quite a few pounds in the ‘teens and gone through the dryer.  Much above 15% starts causing some headaches, though.  The seeds don’t flow well, they start heating fast — and we also usually have higher dockage from the plant heads being wet.
What do you consider to be an “acceptable” seed loss percentage under normal harvesting conditions?
Young —  Every season is different.  You look to see if there are any seeds thrown over; then, if they have any “meat” (kernel) in them — and then make adjustments to air or the sieve as needed.  Sometimes the quality of your final product is improved by cleaning out the lightweight ’flowers.

Coleman — We try to get every seed out, but I’d say a couple seeds in a 3x3 area we would call it good.

Nelson — 2% or lower.

Capistran — It depends on the source of the loss.  Weather and disease can put some seeds on the ground that you can’t undo.  Header loss is where I feel I can improve the most.  It seems like you always get a few stalks knocked over by the point of the pans. (Our 9” pans just don’t match up with 22” rows no matter which way you drive it.)

As far as seed loss out the back of the combine, I don’t want to see anything more than a few “pinny” seeds in the center of the head or empty seeds on the ground.  When I see seed on the ground that I know came out of the combine, pinch it and it’s empty, no problem.  But if there’s good meat in the seed, time to make an adjustment.     
In your experience, what are the key factors (e.g., lodged plants, excess ground speed, improper combine settings, extra-low seed moisture, etc.) that will negatively impact the level of seed loss?

Young — Low seed moisture can lead to increased seed loss.  Everything is more accentuated then: travel faster = more loss; wrong settings = poorer quality.  In central South Dakota, moisture content can change from 11% to 8% in one afternoon.  Making the adjustment “on the go” is very important.  Fan speed and watching the return elevator volume will tell you what adjustments you want to make.

As to lodged plants . . . if they are really bad you have to be ready to walk away and not destroy your machine.

Coleman — I would say all these are critical.  You can’t control downed plants, but you can the rest.  So you focus on those areas.

Nelson — To me, the biggest factors through the years have been lodged, downed plants, Sclerotinia and excessively wet seeds (above 25% moisture).

Capistran — Excess ground speed is a “no brainer.” Calibrate and then believe the loss monitors.  The last two years, we’ve harvested so many wet ’flowers in lousy weather that we’ve found at high moisture on damp days the seeds are sticky enough they won’t fall through the sieve fast enough, leading to high returns.  All we could do was slow down (since waiting for better weather hasn’t worked well lately).
What corrective steps will you typically take, should you consider seed loss to be excessive?
Young — The largest loss, in most cases I have seen, is how the crop is gathered into the machine.  If you don’t have a good way to catch the seeds as the heads are being shaken around, you can lose quite an amount of seed.  Maybe direction of cut can be changed to improve seed savings.

Once the seed is in the machine, it is up to the operator to make the adjustments to get them into the grain tank.  And, sometimes those adjustments may be out of the ordinary.

Coleman — Make sure sieves are clean and not gummed up, especially if you are combining wetter ’flowers in cold conditions.  And, of course, slow down.

Nelson — Wait for drier conditions, consider combine adjustments.

Capistran — (See above combine adjustment comments.)
Aside from dealing with unfavorable harvest weather if and when necessary, will you be “tweaking” any of your sunflower harvest practices this fall compared to prior years?
Young — I am looking into the exhaust control system developed at SDSU to reduce the annoying ember flare-ups.  (Note:  This is the unit discussed in “Combine Fire Research, Experience & Commercially Available Products” as part of the NSA Summer Seminar report in the August/September 2019 issue of The Sunflower.)

Coleman — With our pans, it generally works better to go diagonally with the rows.  Try to adjust up the tips of the pans so seeds that shatter can work their way back into the header.  There also are lift rods available that can help if the ’flowers are leaning badly.

Capistran — I’d like to get pans that average 22” spacing.  A 21-21-24 group would never be off more than an inch (i.e., two-thirds of the pans 18” wide + 3” opening = 21; and one-third of the pans 21” wide + 3” opening = 24).           
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