Harvest Tips & Storage

Color and Small Grain Maturity

With uneven maturity common in many fields, you may have to wait for late grain to mature, while hoping ripe grain does not shatter. Looking at head color and kernel color will enable one to cut as soon as late grain is mature.

Here’s how it works:

• Lack of green in the flag leaf - the uppermost leaf - indicates that a wheat or barley plant has reached 95% of its ultimate yield and that the final stage of development is under way.
• Green disappears from the glumes (bracts at the bases of the spikelets) about 1 1/2 days before maturity.
• Lack of green in heads and the darkening of a pigment strand in each kernel, seen most easily when kernels are cut open crosswise, signal 100% maturity. The pigment strand begins to appear about a half day before physiological maturity.

A whole field won’t lose its color at the same time, so check thoroughly. Also, check bottom kernels on heads because top kernels lose green first.

Preserving Malting Barley Quality at Harvest
Preventing or reducing skinned and broken kernels is the main concern during combining. Skinned kernels are those with more than one-third of the protective husk removed from the kernel. Once skinned and broken kernels exceed 4% of the crop, barley quality and market prices are reduced. Excessive combine cylinder speeds causes the most damage. Cylinder speeds used for threshing wheat are too fast for barley, and should be reduced.

Check the operator’s manual before making speed adjustments. Adjustments should be made in the field according to the harvest conditions. If threshing problems develop at the slow cylinder speed, first reduce the cylinder to concave spacing. Increase cylinder speed only as a last resort and do it in small increments to avoid kernel damage. Keep returns to the cylinder to a minimum. Returning grain to the cylinder for more threshing will cause more problems.

Scouting Canola Maturity Before Swathing
As canola reaches physiological maturity, inspect fields every two or three days for seed color change. This change will first be observed in pods attached at the bottom of the main stem. Variations in fields will cause variations in plant maturity, so check several areas in the field for color change prior to swathing. The suggested time to begin swathing is when a minimum of 15 to 20% of the seed on the plant is showing color change. If hot conditions are expected, producers should consider swathing during the evening or at night rather than during the day. This may reduce the chance of setting green seed due to heat – but this is no guarantee. Review NDSU Extension publication A1171 Swathing and Harvesting Canola for additional information, www.ext.nodak.edu/extpubs/plantsci/crops/a1171w.htm. 

Harvesting Soybeans
Harvest soybeans when plants are mature and the beans have approximately 14% moisture. Harvest may be started at 17 to 18% moisture when air drying is available. Harvest as much of the crop as possible above 12% moisture to avoid cracking seed coats and “splits.” When soybean seed is extremely dry, (8 to 10 % moisture), harvesting will cause more shattering and seed injury. Under these conditions, combine during morning or evening hours when relative humidity is higher and adjust the combine accordingly. Adjust cylinder concave clearance according to the operator’s manual. When soybean plants and pods are tough, cylinder speed may have to be increased.

Decrease cylinder speed as soybean seeds dry during midday to reduce breakage. Gramorie or sodium chlorate can be applied as a desiccant to aid harvesting if green weed growth delays harvest.

Do not apply a desiccant until soybean moisture is under 30% and 65% of the seed pods have reached a mature brown color. Soybeans may be stored safely for short periods during cold weather with a moisture content as high as 14%. For safe storage during the spring or summer, soybean should not contain more than 12% moisture.

Corn Maturity
Corn reaches physiological maturity when the kernel black layer forms at the tip of kernels, and kernel moisture is about 30%. As a general rule in our northern corn growing region, grain corn is usually physiologically mature approximately 50 to 55 days after the mid-silking date, and fairly safe from a killing frost. If corn is mid-silk on August 1, then it would be safe from damaging frost on Sept. 20 or by Sept. 25 depending on maturity. Cool August days and nights can further delay the maturing process. Optimum harvest moisture is 18-23%.  Storage moisture should be 15% short-term, or 13% or less long-term.

Common Harvest Mistake: Leaving Too Much Residue in Windrows
We used to say that residue management started at harvest, but nowadays it is more prudent to say that residue management is an ongoing process. Knowing how much residue you are likely to have at the end of the harvest and making plans now to modify equipment to handle that residue will make residue management much easier.

Proper distribution of residue behind the combine is important. Wide combine headers (>15 feet) and high residue production with today’s varieties are two reasons a well-adjusted combine is critical to no-till farming. Without special attachments or modifications, combine headers of 20 to 30 feet or more are not adequately equipped to spread today’s volumes of residue uniformly.

The most common mistake made in the harvesting operation is to allow crop residue to accumulate in windrows behind the combine. This accumulation causes the soil under the windrows to stay wetter and cooler longer in the spring. Planting into windrows and chaff rows can result in uneven stands, because seeds take longer to germinate and grow, resulting in significant yield reductions. Other problems associated with improper combine residue distribution include:

• Unsatisfactory weed control from herbicide interception.
• Poor performance of planters, drills and tillage equipment (particularly in a no-till system).
• Poor seed soil contact (usually from hair pinning of residue into the seed row).
• Excessive residue laying directly over the seed furrow, resulting in conditions that could inhibit germination or growth.
• Increased pest infestation (from insects and rodents).
• Increased weed seed concentration.
• Poor plant nutrient uptake (from fertilizer tie-up or interception).

To avoid these problems, make sure you always check residue distribution patterns of your equipment, whether it is new or used. The other thing you can do is to consider incorporating some residue spreading attachments. A straw spreader uses rotating blades or rubber batts to throw or deflect whole pieces of crop residue. While the spreader typically distributes the residue more uniformly, the straw chopper can provide more residue cover, since it chops the residue into small pieces before spreading. A straw spreader is effective in handling fine materials primarily from harvest of small grains.

The most commonly used chaff spreading attachments are hydraulically driven single or dual spinning disks that have rubber batts attached. Generally, single disk spreaders are most effective for headers under 20 feet, while dual spreaders are more effective for wider headers.

Rainfall, high temperatures, fall tillage, or knifed in fertilizer applications can all speed the decomposition of crop residues between harvest and planting. As long as moisture is available, decomposition can occur when temperatures are above 50°F. Even when air temperatures drop below freezing, snow can actually act as an insulator and allow decomposition to continue.

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

Proper End-Gate Grain Sampling
To collect a representative sample from a stream of grain flowing from a truckbox end-gate, certain requirements must be met:

1. The material should fall free from the end-gate for about 1 foot.
2. The entire stream of grain (side to side and front to back) must be cut as the sample passes through the stream.

3. The sampling device must not be allowed to completely fill with grain before it leaves the grain stream. If it does, some of the flowing grain will pass around the sampler and not be sampled.

4. Collect a sample from each 500 bushels with a minimum of two cuts per truckload. A cut is a single pass of the sampling tool through the grain stream. Any sampling tool can be used to collect the sample as long as the above requirements can be met.

Harvesting Tips for Dealing With Scab Infected Fields
The following questions have been asked with severe FHB and DON at harvest in the past; the answers are based on past experiences with scab epidemics.

Will I have any insurance or disaster payments?
Before harvest, contact insurance agents and the local Farm Service Agency to determine if any crop loss will be covered, and to learn what insurance contracts require for loss coverage.

Should I swath or straight cut fields with scab?
Straight combining should be considered to minimize further development of the disease or DON production in the swath. Although swathing is generally used to bring moisture levels of grain down faster than with straight cutting, swathing onto wet ground or getting rains on the swath could cause molding and further grain deterioration.

Are there ways to minimize scabby kernels and DON in the harvested grain?
Severely infected fields or portions of fields should be harvested and stored separately, if possible or practical. Scab severities and DON levels may be higher in portions of field adjacent to drown-outs or in very low areas. Research at Michigan State University showed that the highest concentrations of DON were along field margins and in headlands in fields that had no problems with drown-outs.

Use mechanical separation of scabby grain. Set combine fan speed to blow out shriveled, diseased kernels that cause problems in marketing and storage. Scabby kernels in the harvested grain may add to yield, but will diminish market price.

Additionally, harvested grain can be further cleaned by gravity tables which may reduce the level of scab enough for achieving top market grade and price in the cleaned sample.

Farm workers and grain handlers should minimize exposure to grain dust in fields with scab, using enclosed cabs with good air filtration systems, and using dust masks when transferring grain.

What can be done with scabby grain that can’t be marketed?
NDSU studies show that cattle and sheep are most tolerant of the DON. Hogs are most sensitive to DON, even at one parts per million contamination of hog feed. The toxin also can cause problems in horses, dogs, and other single stomach animals. With any questionable grain, it is advised to contact a Extension livestock specialists, veterinarian, or feed specialist before feeding grain infected with DON to livestock.

The Food and Drug Administration has guidelines for DON levels in grain:

• 1 part per million for finished grain products for human consumption (Many food processors and malt barley companies have stricter requirements)
• Cattle over 4 months old: 10 ppm (providing grain at that level doesn’t exceed 50 percent of diet)
• Swine: 5 ppm (providing grain at that level doesn’t exceed 20 percent of diet)
• Poultry: 10 ppm (provding grain at that level doesn’t exceed 50 percent of diet)
• All other animals: 5 ppm (providing grain at that level doesn’t exceed 40 percent of diet)
• Straw from scab-affected fields should be suitable for cattle and sheep bedding, but is not recommended for horses.

What about storing affected grain?
Drying won’t reduce scab or DON levels, but drying prevents further fungus development. Moisture content of scabby grain going into storage should be about 12 percent.

Grain Temperature Key to Grain Storability
Maximum recommended moisture content for wheat is 14% (wet basis) for up to 9 months storage, and 13% for more than 9 months storage. Barley moisture should be 13.5% and 12.5%, respectively, for the same storage periods.

Dry grain should be cooled to less than 60° as soon as possible after harvest, and to 20 or 30° for winter storage.

Wheat Drying Time (69^oF and 60% relative humidity. Average ND condition for August)

Moisture Airflow Fan Time Content (cfm/bu) Hours Days 18% 1.25 1.00 480 600 20 25 17% 1.00 0.75 552 744 23 31 16% 1.00 0.75 0.50 504 672 1,008 21 28 42 15% 1.00 0.75 0.50 480 648 960 20 27 40 14% 1.00 0.75 0.50 408 544 816 17 23 34 Above is the expected time required to natural air dry wheat and the recommended airflow rates for various wheat moisture contents for average August conditions. It is not recommended to natural air dry wheat at moisture contents exceeding 18%, because of the potential for grain quality loss before the wheat is dried and the excessive fan horsepower required to provide the needed airflow rate. Most systems are designed for an airflow rate of 0.75 cfm/bu, which permits drying wheat with initial moisture contents up to 17% and drying to be completed within one month. (Source: Ken Hellevang, NDSU Extension Ag Engineer)

Stored grain should be cooled by aeration whenever the grain temperature exceeds the average outdoor temperature by 10 to 15 degrees. Expected allowable storage time approximately doubles with each 10 degree reduction in temperature. Grain should be cooled to about 25 degrees as outdoor temperatures get colder. Grain that has been dried with high temperature dryers will have a moisture variation across the kernel as it comes from the dryer. This will cause an error in the moisture measurement. The grain should be checked at least 12 hours after drying to determine if the grain moisture content has changed.

Check the condition of stored grain about every two weeks while grain is cooling, then about monthly after grain has cooled. A check should include measurements of moisture content and temperature at several locations. Moisture measurement accuracy is dependant on the grain temperature, so it is best to collect a grain sample, let it warm to room temperature in a plastic bag or other sealed container, then check the moisture content. Also, be sure to cover fans and ducts after the grain has been cooled for winter storage to prevent snow from blowing into the bins.

Eastern ND Environment

			Equilibrium Moisture Content (EMC)
Month	Temp (oF)	Relative Humidity	Wheat	Corn	Oil Sunflower	Soybeans
August	67	66%	14.1
September	56	68%	15.0
Oct/Apr	44	69%	15.9	16.0	9.0	13.4
Nov/Mar	25	78%	19.0	19.5	11.0	17.0

How to Estimate Grain Harvest Losses
Studies have shown that losses off the combine can run as high as 20%, even with a properly adjusted machine when it is overloaded. A reasonable loss is considered to be 3% of the total crop or less. Total harvest losses are seldom if ever zero.

Usually over 60% of the grain left in the field is due to shattering of the crop and grain lost in getting it cut and into the combine header. Once the crop is in the combine, loss is very low with properly adjusted and operated equipment.

To keep harvest loss low, determine how much grain is being left in the field. A simple, accurate method to estimate losses requires the use of a one-foot square frame. Pick several typical areas in the field after the combine has passed and follow these steps.

1. Count the kernels left directly behind the rear of the combine. Count several separate square foot areas (A- Figure 1).
2. Count the kernels already in the field due to shatter and cutter bar loss (B- Figure 1).
3. Subtract (B) from (A).
4. Divide the results of Step 3 by the ratio of: Width of windrower/header width (ft) Width of combine (ft).
5. Divide the result of Step 4 by the number of kernels for the particular crop from the Table 1 (below) for one bushel per acre loss. This is the approximate machinery loss in bushels per acre.
6. To find total loss, add the count in (B) to the result in Step 4. This gives the total seed count from shatter, cutter bar and machine loss.
7. Divide the total seed count of Step 6 by the number of kernels for the particular crop for one bushel per acre loss (Table 1). This will give the approximate total loss in bushels per acre.
8. For a percentage loss, divide the loss in Step 7 (loss in bushels per acre) by the total yield (harvest yield plus loss) in bushels per acre for the field.

   Table 1: Number of kernels per square foot to equal one bushel per acre loss

Crop Number of  Kernels / ft2 HRS Wheat 20 Durum 16 Barley 14 Oats 10 Source: University of Minnesota Extension Service

Counting Kernels to Measure Harvest Loss
Kernels or seeds per pound, bushel, cwt, and number per square foot to equal one unit loss per acre at harvest

Crop No. per pound* to equal 1 bushel unit loss/A No. per square foot Spring Wheat 14,300 20 Durum Wheat 11,500 16 Barley 13,500 15 Oats 15,500 11 Flax 88,000 113 Rye 18,000 42 Soybeans (Small) 3,300 4 Soybeans (large) 2,400 4 Corn (Medium grade) 1,500 2 Sunflower (oil) 9,000 5 Sunflower (confc.) 5,000 2.5 Navy Beans 2,500 4 Pinto Beans 1,250 2 Sorghum 15,000 18 Sudangrass 44,000 40 Proso Millet 80,000 84 Foxtail Millet 220,000 242 Buckwheat 15,000 16

* These are average numbers from past seasons, and individual varieties or hybrids will vary among themselves as well as be influenced by environmental factors. Source: NDSU

Specialty Crops - When To Swath and Combine

Crop	Other Information
Peas	When swathing, seed needs to be at physiological maturity. At this stage, majority of pods should have turned from green to yellow. The crop matures from the bottom pods upward. Peas should be swathed in the early morning or late afternoon when the pods are tough to reduce shattering losses. Field peas should be combined with seed moisture of 14 to 20%. At this moisture range, the seeds are firm and no longer penetrable with a thumbnail. Harvest should occur during humid conditions to minimize seed shatter. However, pea vines must be dry or harvest will be extremely slow and difficult. Seed that is too dry will be susceptible to seedcoat breakage or peeling.
Lentil	Swath when lower most pods are tan colored and rattle when shaken. Thresh when seeds test 18% moisture content or lower. Overdry lentils (8-10%) are hard and difficult to process or consume. Plants may still be green when pods are ripe. Crop typically matures in patches. Some shatter loss usually occurs. Watch out for swaths being scattered by the wind.
Mustard	Swath when seed moisture content is 25%. Seeds are firm when pressed between fingers. Oriental - 75% yellow seeds. Brown - 60% reddish brown seeds. Yellow - 100% yellow seeds. Straight combine yellow mustard whenever possible. Watch for cracked seeds. Moisture content of seed should be 13% or lower. Swaths are fluffy and subject to wind damage. Lay swaths in direction of prevailing winds. Immature green seed will not change in color in the swath. Use swath roller.
Safflower	Crop has finished blooming. Seeds heads are tan to brown in color. Leaves and heads are spiny with little green evident. Crop should be straight combined if evenly matured. Mature seed is striped or white and rubs freely from the heads.
Flax	Flax maturity can be judged by the color of the bolls. Flax should be harvested when 90% of the bolls turn brown. The stems may remain green after the bolls are ready to harvest. Flax with green stems is the most difficult of all grains to cut. Sharp, well adjusted cutter bars are essential. Flax can be straight combined if maturity is uniform and green weeds not a problem. If flax is swathed and pickup combined later, a tall stubble is desired. Using swath rollers can help settle the swaths into the stubble to reduce wind damage and aid pickup combining. The seedcoat of flax is easily damaged or broken, so proper adjustments are necessary. Yellow seeded varieties are more susceptible to seed damage because of their thinner seedcoat.
Sunflower	Physiological mature when bracts are yellow/brown and little green remains on back of heads. Common threshing mistake: waiting to harvest and seeds become too dry and shell out. Better: combine at 14-15% moisture and dry down to under 10% moisture.
Duane Berglund, NDSU extension agronomist

Tips to Maintain Quality When Drying Small Grain

NDSU research has shown the air temperatures at which milling and baking damage become apparent for hard red spring wheat are 160°F for 16% moisture content; 140° for 20% initial moisture content; and 120° for 24% moisture. These values are for airflow rates of 100 to 150 cubic feet per minute per square foot.

To keep kernel temperatures below 120°, reduce drying air temperature 10 degrees for an airflow of 50 cubic feet per minute per square foot.

In all cases grain nearest the heat source is most severely damaged.

Durum is very sensitive to dryer temperatures. With higher drying temperatures, the percentage of specks in the processed semolina increases.

For barley, NDSU research has shown the maximum allowable drying air temperature is 130°, and the maximum harvest moisture content, 20%.

Since the burner of a dryer cycles on and off, it’s safer to use a temperature lower than 130°.

Grain Drying And Storage Info Online

NDSU Grain Drying, Handling, and Storage Info and Links -- www.ag.ndsu.nodak.edu/abeng/postharvest.htm

University of Minnesota Grain -- www.extension.umn.edu/listing.html?topic=2&subcat=44

U of M Grain Storage Links -- www.bae.umn.edu/extens/postharvest/tempstor.html