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Grains:Harvest and Storage Tips

Color and Small Grain Maturity
With many fields experiencing uneven maturity, you may have be patient while late grain matures, while at the same time hoping that ripe grain does not shatter. Looking at kernel and head color will allow you to cut once late grain is mature.

Here’s how it works:

  • Lack of green in the uppermost leaf – the flag leaf – is an indicator that a barley or wheat plant has reached 95% of its eventual yield and that the final stage of development is in progress.
  • Green fades from the glumes (bracts at the bases of the spikelets) about 1.5 days before reaching full maturity.
  • Lack of green in heads and the darkening of a pigment strand in each kernel, seen most readily when a kernel is cut open crosswise, signal full maturity has been reached. The pigment strand starts to show about a half-day before physiological maturity.

Because an entire field won’t lose its color at the same time, you should check thoroughly. Also, because top kernels lose green first, make sure to check bottom kernels on heads as well.

Preserving the Quality of Malting Barley at Harvest
The primary concern during combining is the prevention and reduction of skinned and broken kernels.  Skinned kernels have more than a third of the protective husk removed.  Once broken and skinned kernels reach levels of more than 4% of the crop, the quality of the barley is reduced and market prices drop.  The most damage is caused by excessive speeds in the combine cylinder.  The cylinder speeds used for threshing wheat should be reduced before threshing barley.

Before making speed adjustments, make sure to check the operator’s manual.  Adjustments ought to be made in the field relative to the harvesting conditions.  If slow cylinder speeds seem to be causing threshing problems, the cylinder should first be reduced to concave spacing.  Increasing the cylinder speed should only be used as a last resort, and done in small increments to prevent kernel damage.  Returns to the cylinder should be kept to a minimum, as returning grain to the cylinder for further threshing will cause additional problems.

Scouting Canola Maturity Before Swathing

Inspect fields every two or three days for changes in seed color as canola approaches physiological maturity. You will first notice this change in pods attached to the bottom of the primary stem.  Any variations in your fields can cause variations in the maturity of your plants, so be sure to inspect several regions in the field for color change before swathing.  The recommended time for starting to swath is when at least 15-20% of a plant’s seeds are showing a change in color.  If hot weather conditions are forecast, producers should look into swathing during the cooler evening or night hours instead of during the day, which might reduce the chance of green seed setting due to heat, but there are no guarantees.  Review NDSU Extension publication A1171 Swathing and Harvesting Canola for additional information.

Harvesting Soybeans
Soybeans are best harvested when plants are fully mature and the beans have a moisture content of approximately 14%.  However, the harvest may begin at 17-18% moisture if air drying is a possibility.  The majority of the harvest should occur with moisture levels above 12% so as to avoid “splits” and cracking seed coats.  When soybean seed reaches 8-10% moisture, harvesting causes more seed injury and shattering.  Under those extremely dry conditions, it is recommended to combine during earlier and later hours of the day, when the relative humidity is higher.  The combine should be adjusted according to the operator’s manual with respect to cylinder concave clearance and cylinder speed, as the latter may need to be increased when soybean pods and plants are tough.

As harvesting occurs during the midday hours, you will likely need to decrease cylinder speed to reduce breakage as soybean seeds dry.  Sodium chlorate or gramorie can be used as a desiccant to assist in harvesting if harvesting is delayed by green weed growth.  However, desiccant should not be applied until 65% of the seed pods have a mature brown color and soybean moisture levels are below 30%.  During cold weather, soybeans may be safely stored for short periods, even with a moisture content as high as 14%.  During the spring or summer, soybeans should have a moisture level no higher than 12% to ensure safe storage.

Corn Maturity
When the kernel black layer forms at the tip of kernels, and kernel moisture is about 30%, corn has reached physiological maturity. As a general rule in a northern region of corn growing, grain corn is usually physiologically mature around 50 to 55 days after the mid-silking date, and relatively safe from a killing frost. For example, if corn is mid-silk on August 1, it would be safe from frost damage between September 20-25, depending on its maturity. However, cooler temperatures in August can further delay the process of maturation. The ideal moisture for harvest is 18-23%.  On the other hand, storage moisture should be 15% for short-term, or 13% and below for long-term.

A Common Harvest Mistake: Leaving Too Much Residue in Windrows
It used to be said that residue management began at the time of harvest, but in this day and age it is wiser to consider residue management as continual process.  Residue management is far simpler when you know how much residue you are likely to have when the harvest is over, and when you make plans in advance as to how to modify your equipment to handle the amount of residue expected.

It is critical to consider the best distribution of residue behind the combine.  High-residue production with today’s crop varieties as well as combine headers in widths of 15 feet or more are two reasons why a well-adjusted combine is essential for no-till farm operation.  Unless they have modifications or special attachments, combine headers in excess of 20 feet are not suitably equipped to uniformly distribute current volumes of residue.  Allowing crop residue to build up in windrows behind the combine is the most common mistake made in harvesting operations today.  This buildup makes the soil under the windrows cooler and wetter for a longer period in the spring.  Uneven stands can result from planting into chaff rows and windrows, as seeds usually take more time to germinate and grow in those conditions, leading to significant reductions in yield.

Other problems related to the improper distribution of combine residue include:

  • Poor performance of drills, planters, and tillage equipment (especially in a no-till system).
  • Poor soil-seed contact (typically from hair-pinning of residue into the seed row).
  • Poor uptake of nutrients by plants (due to fertilizer interception or tie-up).
  • Excessive amounts of residue laying immediately over the seed furrow, leading to conditions that inhibit germination and/or growth.
  • Unsatisfactory weed control due to herbicide interception.
  • Increased pest infestation (of rodents and/or insects).
  • Increased concentrations of weed seed.

Being sure to always check the patterns of residue distribution of your equipment can help you avoid these problems, whether your machinery is new or used.  Furthermore, consider utilizing some residue-spreading attachments.  For instance, a straw spreader uses rubber batts or rotating blades to deflect or throw whole pieces of crop residue. While a spreader generally distributes the residue more evenly, a straw chopper can offer more residue cover, because it chops the residue into smaller pieces before spreading. A straw spreader is most effective in handling fine materials primarily derived from the harvest of smaller grains.

The most frequently used chaff-spreading attachments are hydraulically-driven single or dual spinning disks with attached rubber batts. In general, single-disk spreaders are best with headers less than 20 feet, while dual spreaders are most useful with wider headers.

Fall tillage, high temperatures, rainfall, or knifed-in fertilizer applications can all accelerate crop residue decomposition between harvest and planting. Decomposition can occur when temperatures are above 50°F as long as moisture is present. Even if air temperatures fall below freezing, snow may act as an insulator, allowing decomposition to continue.

Residue from fall-seeded cover crops, potatoes, sunflower, canola, peas, beans, and sugar beets decomposes at a faster rate than residue from corn, grass hay, alfalfa, oats, wheat, or sorghum.

Proper Sampling of End-Gate Grain

In order to gather a representative sample from a stream of grain flowing from a truckbox end-gate, the following requirements need to be met:

  1. The grain should fall freely from the end-gate for approximately one foot.
  2. The entire grain stream (both side-to-side and front-to-back) must be cut as the sample passes through the stream.
  3. The sampling device must not be permitted to fill completely with grain before leaving the grain stream. If that occurs, some of the flowing grain will pass around the sampler without being sampled.
  4. Collect a representative sample from every 500 bushels with at least wo cuts per truckload. A cut is one pass of the sampling tool through the grain stream. Any sampling tool is appropriate for collecting the sample as long as those requirements are met.

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