| UNDERCUTTING |
- If beans are grown in row crop situations they may be first pulled (undercut).
- Pulling should start when the bottom pods are dry and most of the pods are yellow.
- Pulling beans involves cutting them off ¾ to 1 inch below the soil surface with either a fixed blade, rotary disc-type, or a rod-weeder type.
- Undercutting equipment must be sized according to row spacing, as equipment designed for 22 inch rows will not work for 36 inch row spacings.
- The blades on most cutters can be set at two different angles and may be shimmed to alter the angle at which they enter the ground – soil texture, compaction and soil moisture will all be determining factors for the preferred cutter settings.
- Beans are then allowed to lay and dry for a period of time dependent on maturity and moisture. If beans are quite mature, pulling may be done only an hour or two prior to combining to allow soil on the roots to dry.
- Some immature pods will dry down in the row after being cut off if left for several days, but the risk of moisture wetting and moulding beans increases the longer they are laying out.
- Proper completion of the hilling operation during the growing season will definitely make it easier to cut the crop.
- If a proper cutting edge is not maintained, a poor cutting job will cause heavy harvest losses – it’s essential to periodically check the performance of the bean cutter in case it requires re-adjustment.
- The use of a rod to lift the roots out of the soil after undercutting is a common harvest practice – the rod ensures that no plants are left uncut or are held tightly by the soil.
- A rod may be used either at the same time as cutting or immediately before combining, but a rod application should not be used at the same time as undercutting if the crop is overripe, as the crop will be at high risk of blowing – under these conditions, the rod should be used just ahead of the combine.
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| WINDROWING |
- Once the beans are undercut, 6 to 12 rows are then windrowed together to make a swath for combines to pick up.
- Keep some green vegetation on the plant so that windrows will not be moved by strong winds while the curing process is taking place.
- Although windrowing is not a preferred operation in harvesting a bean crop, windrowing may be necessary depending on the type of harvest equipment used.
- Windrowing may be done by using a conventional windrower or a side delivery rake.
- Some growers windrow at the same time as undercutting, and others just prior to combining.
- If the crop is to be windrowed just prior to combining, it should be done when the crop is tough to reduce shattering.
- Do not windrow any more than can be combined in one day because wind will move the bean swath.
- Care should be taken to reduce shattering when windrowing. Early morning or evening can help reduce shattering losses to windrowing in some cases.
- Indeterminate vine-type beans grown in 30 to 36 in rows are best suited for this process.
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| SWATHING |
- Beans grown in solid seeded systems are often swathed prior to combining.
- Swathing occurs at a similar stage to pulling, when 50% to 70% of the pods are in a buckskin stage.
- A few leaves left on the plant will help limit shatter losses, but green material can gum up on the knife and require cleaning.
- Vine lifters and pickup reels can be beneficial to reduce losses by helping to get lower pods.
- As with pulling, swaths are susceptible to both wind damage and rotting if swaths get quite wet from rain.
Dry Beans |
| COMBINING |
- Bean crops cut at the proper stage require approximately 7 to 10 days of good drying weather before they are ready for combining.
- To minimize seed damage, dry beans should be combined when the seed moisture content is between 18% to 22%, as combining below 14% greatly increases the risk of cracking.
- If moisture drops too low and cracking becomes an issue, waiting until moisture increases in the evening or early morning may be necessary.
- If bean seed becomes too dry, the percentage of splits and cracks will increase during harvest and post-harvest handling.
- Combines may either be specialized units designed specifically for harvesting dry bean or conventional units with either a cylinder or rotor threshing system.
- Special bean combines such as the Bedwell or Lilliston have one or two cylinders. The bottom of the combine is a large screen and beans are moved around on conveyors to let dirt fall out. They are excellent for reducing damage to beans harvested in hot, dry conditions, especially when growing high-value coloured beans. However, they are a significant investment and if beans are a smaller acreage on a grower’s farm, conventional combines and rotary combines can be used.
- In general, rotary combines are gentler on beans than conventional combines, especially if you can keep the rotor full to help cushion the beans. Cylinder speeds should be set as low as possible and adjusted during the day as beans dry. Concave spacing should also be increased during the day as beans dry down.
- Conventional combines can be modified to be gentler on beans and allow more dirt to fall through earlier in the process to reduce earth-tag if a grower wants to have a combine for exclusive use on beans.
- A number of harvest equipment combinations are:
- Cut and rod in the same operation at 70% buckskin pod colour. Pick-up and combine. For normal row crop production of dry bean, this option results in the lowest harvest cost per acre while doing a good job of minimizing harvest losses.
- Cut the crop at 70% buckskin pod colour. Rod just prior to combining. Pick-up and combine.
- Cut at 70% buckskin pod colour. Rod just prior to windrowing. Windrow just prior to combining. Pick-up and combine.
- Desiccate solid seeded upright/bush bean at 85% to 95% buckskin pod colour. Straight combine. This option is only viable for upright or bush types grown in a solid seeded field. A flexible header on the combine is necessary for this method of harvest, and lifter guards are also recommended for straight cut operations.
- Dry beans may also be straight cut when 75% of the pods are dry and the remaining pods are in the buckskin stage.
- It is recommended to use a harvest aid if enough weeds are present, or a desiccant to allow for quick plant dry down so the seed does not over dry while waiting on leaves and stems to dry down.
- Some products may leave residues and checking with your buyer for market acceptance of desiccants used is a good idea. Some products are also moved through the plant and should not be used if crops are grown for seed purposes
- Use of vine lifters or flex headers to maximize ability to capture low pods can be helpful.
- Straight combining works best if the crop is even and free of green weedy material.
- Vine type varieties (most often grown in southern Alberta) do not straight cut well, as pods often touch the ground, resulting in excessively high harvest losses.
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| COMBINE SETTINGS |
- Dry bean is very susceptible to splitting and cracking, so the rpm of the cylinder and the clean grain elevators should be reduced as much as possible – cylinder speeds between 170 and 350 rpm are satisfactory for most threshing conditions.
- Clearances between the cylinder and concave, and between the wires in the concave, must allow the seed to pass through freely.
- The use of perforated sheet metal (3/16 round) and slotted screens in the feeder housing or screening on the combine table will help eliminate dirt from the grain – and save wear and tear on the equipment.
- The unloading auger should run at an idle speed to prevent damage to the seed – if you see evidence of seed damage or splitting, make immediate adjustments.
- Two popular types of combine pick-ups are “Sund” and “Rake-Up”. Pick-up speed should not exceed the ground speed of the combine, to reduce shelling and pod loss.
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