Clean, Quality Organic Grain
By Bob Scharlau
This article was first printed in the March/April 2009 issue of the Organic Broadcaster, published by the Midwest Organic and Sustainable Education Service.
Deciding to grow and sell organic grains requires some planning to get a profitable outcome. For example, your crop rotation may help dictate what grain to plant. Soybeans will be less weedy following hay than following corn. Eventually you will have to rotate to a cereal grain like oats, barley or wheat. Consider if you can include a green manure crop into your rotation, such as winter rye, winter wheat, buckwheat , rye grass, clover or alfalfa.
Input costs bring up another issue. Corn and wheat seem to need more fertility than soybeans, hay or oats. Corn, soybeans and alfalfa seed are more costly per acre than oats and barley.
Have a plan of who might buy your crop and how to deliver it. Call grain buyers and feed mills- refer to the MOSES upper Midwest Organic Resource Directory for phone numbers and contact info. Ask the buyers which grains are most in demand and what a likely delivered price range is. While you are in the planning stage, figure out who can harvest the grain and who can haul it during the rushed harvest season. Do you have grain storage, so you can store the crop and sell when prices are higher, like from December through June, or must you sell off the combine?
You will need to understand harvest options to obtain a saleable product free of thrash and dry enough to store. Organic crops will have some weeds. Corn and soybean harvest can wait for a killing frost, so the weeds can freeze dry and pass through the combine as shredded up weed parts and the combine fan can blow it out. With oats, barley and wheat (July-August harvest) the weeds will be green and moist and difficult to separate from the grain, requiring more horsepower and less acres per hour while running the combine.
Small grains allow you some harvesting choices. Own or hire a custom combine that offers swathing the grain into windrows, leaving 3-6 inches of uncut straw to hold the swathed grain up off the ground to dry the weeds and grasses. It often takes three days to dry and if it rains just wait longer until it re-dries. If a swather and combine with a belted pick up are not available, then the next best option may be a haybine. A haybine with the conditioner rolls blocked open can serve as a swather. If the haybine knocks the grain heads off, slow down your engine speed and/or swath in the morning when the dew is still in the crop. Float the haybine head to keep a standing stubble and form windrows so no tire tracks drive on the windrow. Not driving on the windrow is easier with a self propelled than a pull-type haybine.
Next, if a combine with belted pickup head is not available, you can use a direct cut grain head or a soybean head and run the head just low enough to cut a minimum of the standing stubble. The combine reel will pull the dried windrow into the combine and blow the chaff and weeds out of the grain. The combine will usually pull the grain in more evenly when the heads of the grain enter first, rather than the stems first.
If you are forced to direct combine small grains with green grass and weeds, prepare to deal with wet husks of weed stem in your grain. You will have 12 to 24 hours to get air movement before it starts to heat and mold. Use a grain bin with perforated floor and a fan, or a screw-in pipe fan may work in wagon boxes if the volume is 100 bushels or less.
If you plan to sell the grain, most buyers will require clean grain, or else the buyer will screen the thresh out and charge you for doing it. You will get paid for clean dry bushels only. If you were buying grain, would you want weeds, chaff and moldy grain? That’s why you will want to swath and air dry in the field.
The art of combining grain is a function of the operator. If a harvest doesn’t plug and stop the combine, a combine driver will just turn up the radio and keep on driving. Many custom hire combines just want to cover the acres and move on. To get clean grain in the grain bin requires an operator, not a driver. The landowner has to be present and demand precision adjustment to get clean grain. Every brand of combine is capable of obtaining clean grain.
If using a custom hire combine, you must first flush some organic grain through to remove any conventional grain still in the machine. You will also need to clean hidden areas of grain residue. For example , open the traps and doors to vacuum or blow out conventional grain. Then combine 30 to 50 feet of organic crop, stop and empty that into a wagon, so you can sell it to the neighbor's horse or whatever. Next combine 100 feet or so, stop the combine and look at what is in the grain bin and what is left on the ground behind the combine.
The operator’s manual will give specific adjustments for each grain crop, such as cylinder speed, cylinder to concave clearance, fan speed, chaffer opening and sieve opening. These are the things that will adjust the combine to achieve clean grain in the bin. Here are some guidelines of how to interpret these adjustments.
- Cylinder speed: if the manual says 900-1200 RPM for oats, then adjust to obtain 1000 and try it.
- Cylinder to concave space or clearance is the opening that all the crop has to pass though when the cylinder or rotor threshes the grain into the stationary concave, causing the removal of seed from cob or stem. Too little clearance smashes the seed and/or grinds up the stems. Too much clearance leaves seed on the cob or stem unthreshed. For oats the book may say one half inch. Try it and check for smashed seed or unthreshed grain on the ground behind the combine. A rule of thumb is to increase cylinder clearance until you’re not threshing enough seed, then reduce the clearance to thresh all the seed. Same with cylinder speed; reduce speed until you’re not getting all the seed off the cob or stem.
As the sun goes down and the dew starts to form, you should quit, but if you need to keep going you may have to increase cylinder speed and/or clearance. If you’re smashing soybeans, open clearance and/or slow cylinder speed.
- Use maximum fan speed, but you’ll have to decrease if you’re blowing seed out the back of the combine. Check by looking on the ground behind the combine and under the straw or stalks. The combine manual will give a fan range for each grain that will most likely be correct. Dust and chaff in the grain bin would indicate too slow a fan speed.
- Chaffer adjustment (the upper shaker in the back of a combine). The fan blows the threshed grain and stem material over an adjustable screen called a chaffer. You want most of the stem material to not fall through, but blow out the back onto the ground. You want all the seed to fall through to the chaffer and stay in the combine. The book adjustment for oats might be one quarter inch. If you are getting stems in the grain bin, keep closing the chaffer openings. If the seed is going out on the ground, open the chaffer and/or slow the fan speed.
- Sieve adjustment (the lower shaker- horizontal screen). What falls through the sieve will end up in the grain tank. The book adjustment might be a quarter inch for oats. If you are getting thrash into the grain bin, keep closing the sieve opening- if it is entirely shut and you are still getting thrash, increase the fan speed.
Note that most combines have a return elevator bringing some material back to the cylinder to be re threshed. Usually this return material can be viewed by the operator while in operation. The return flow should be minimal- less than 5% of the volume flowing into the grain tank. Excess return flow means the chaffer is letting too much thrash fall through, and you need to close the chaffer more.
Bob Scharlau has been a certified organic crop farmer for 20 years and is co-owner of S & S Grains feed mill.
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