Take Disease Notes, UNL Soybean Harvest Moisture Study, Grain Drying Review  09/28/16 8:15:38 AM

TAKE NOTES—I am seeing more “Damping off” in soybeans in recent days.  Although the crop is near maturity and it will likely not impact yield, it will pay you in 2 years to remember where in your fields you have experienced the problem.  The rule is if damping-off occurs in warm soil (70 to 80 degrees) it is more likely to be caused by Phytophthora Root Rot (PRR).  Damping off occuring in cool soils in the Spring--(50-60 degrees) it is more likely to be caused by Phythium.   Both diseases cause the root and lower stem tissue to turn brown/purple with a slimy texture, which can lead to seedling death.  There are upwards of 45 races of Phytophthora, which greatly complicates breeding for resistance and adds confusion to growers when selecting appropriate resistant varieties. The specific gene resistance, known as the Rps1 gene that is bred into many soybean varieties provides protection against several known races of PRR.  The gene Rps1a provides protection against 17 races of Phytophthora; Rps1c, against 23 races; Rps1k, against 24 races. However, none of these specific genes provides protection from race 25, which is common in many areas in Eastern Nebraska. 

PRR may attack soybeans at any growth stage. Older plants of affected low-tolerance varieties may be killed gradually. The roots turn brown and the upper leaves become yellow between the veins and leaf margins, accompanied by complete wilting of the plant. Generally, symptoms occur on isolated plants scattered across areas of a field, rather than large patches of infected plants as we saw with sudden death syndrome or soybean cyst nematode damage last season.


SO WHAT CAN BE DONE? Acres that are intended to be planted to soybeans in 2018, should have some considerations from the 2016 crop or the previous history of soybeans on these acres.  If you have had stand reduction from a disease and have determined the causal agent, genetic tolerances are the initial and standard first line of defense.  Most, if not all, seed brands have listings for their product line-ups on PRR, SDS, and Brown Stem Rot. What happens if genetic tolerances aren’t enough? Since Sudden Death Syndrome has become a topic in the past few years.  You might consider sampling these suspect areas for Soybean Cyst Nematode.  It appears the SDS infection rates, and areas of infection, are higher in areas with higher populations of Soybean Cyst Nematode.  Although the research and data to support that statement is still un-proven, it does make sense that if nematodes are affecting the vascular flow of water and nutrition to the plant that the plant would have less defenses towards SDS and/or other root diseases.   Planting varieties with good SCN tolerance AND SDS tolerance is a good base practice.  This consideration can also be supplemented with the use of seed treatments containing Ilevo.  Yes, it does come at a cost, but, if you have documented PRR, SCN, and SDS injury in your fields, the question becomes how much yield did you lose and what did that cost you?




Below is an article published via UNL’s Cropwatch Newsletter which details some considerations when harvesting soybeans.  This is VERY appropriate given our current weather and soybean development situations.




Randy Pryor - Extension Educator


Paul Jasa - Extension Engineer


Gary Zoubek - Former Extension Educator


Most soybeans are harvested and delivered directly to an elevator instead of being placed in on-farm storage. Too often, soybeans are harvested at moisture contents under the 13% definition of a standard bushel. The marketplace pays farmers as if they delivered soybeans at 13% moisture. That's why 13% moisture needs to be the goal — delivering soybeans below or above that goal reduces profits.

Greater than 13%, there is a moisture dock on the scale ticket for delivering wet beans, resulting in a lower price per bushel.  Less than 13%, there are fewer “bushels” to sell rather than a dockage on the ticket. There are fewer bushels because the load weight is divided by 60 pounds per bushel (assuming 13% moisture) rather than by the actual pounds per bushel for the moisture content of the beans at the time of delivery

A study of farmer practices was conducted in Hamilton and York counties by former extension educators Andy Christiansen and Gary Zoubek. They collected information from 115 truckloads of soybean that were harvested and being delivered to the elevators. Of those sampled, 5 loads were less than 8.9% moisture; 14 loads were 9-9.9%; 28 loads were 10-10.9%; 27 loads were 11-11.9%; 29 loads were 12-12.9%; 9 loads were 13-13.9% and only 3% loads were 14-14.9% moisture.

What difference does harvesting and selling soybeans at 8% or 9% compared to 13% moisture mean to your bottom line?

If you sell soybeans at 8% moisture, you're losing about 5.43% of your yield; at 9% moisture, it's 4.4%; at 10% moisture, 3.3%; at 11% moisture, 2.25%; and at 12% moisture, it's 1.14% yield loss. That does not take into account additional risk for shatter losses during harvest. For a field that's yielding 75 bu/ac, harvesting it at 9% results in selling 3.3 fewer bushels per acre based on weight because you are not selling the water that you are entitled to sell if the beans were at 13% moisture. With soybeans priced at $9/bushel, that's a loss of about $30 per acre.

So what can you do? Everyone knows that it is impossible to harvest all your soybeans at exactly 13%, but that should be your goal. Consider these soybean harvest tips:

In a study of soybeans being delivered to elevators in two counties in south central Nebraska, only 8% were delivered at the target level of 13% moisture while 90% were delivered below 13% moisture and 2% were delivered over 13% moisture. While not all soybeans can be delivered at 13% moisture, that should be the goal.


Table 1. Potential loss from delivering soybeans at less than 13% moisture.













    1. When harvesting tough or green stems, make combine adjustments and operate at slower ground speeds. Make combine adjustments several times a day to match conditions as they change. The following combine adjustments are suggested when harvesting higher moisture soybeans or soybeans with green stems:
      • To increase “grip” on the green stems to pull them through the combine, replace rounded or worn parts in the thresher, especially worn feeder house chains and rasp bars.
      • Increase cylinder/rotor speed to make threshing more aggressive to break open green pods and pull the green material through. Do not close down concave clearance as that reduces room for the green materials to pass through the thresher.
      • Insert filler plates or wires in the front portion of the concave to keep the green pods in the cylinder/rotor chamber longer for better threshing. If not, the pods will fall through to the sieves unopened. Consider closing down the top sieve slightly to send the green pods out the back if you are not threshing them properly.
      • Increase fan speed as the green stems are heavier and need more airflow to keep them suspended above the sieves to allow for proper cleaning and to blow the green leaves out.
      • Close down the lower sieve slightly to keep green pods out of the grain tank and send them back to the cylinder/rotor for rethreshing.
      • Install disrupter bars on rotary combines to improve green stem flow through the rotor and to reduce “roping.”  On some rotary combines, you can retard the material flow by adjusting the vanes on the rotor cage or by installing reverser rasp bars to keep the material in the rotor longer to allow more time for threshing and separating.
      • Consider adding an air reel to the head to have airflow help feed the soybeans into the combine and reduce bunch feeding.  More uniform feeding will improve threshing.

    2. Begin harvesting at 14% or 15% moisture. What appears to be wet or green from the road may be dry enough to harvest. Try harvesting when some of the leaves are still on the plant as the beans may be drier than you think. Soybeans are fully mature when 95% of the pods are at their mature tan color. The moisture driven from the wet beans in the bottom of the bin will help rehydrate any dry beans in the top of the bin.

    3. Harvest under optimum conditions. Moisture content can increase by several points with an overnight dew or it can decrease by several points during a day with low humidity and windy conditions. Avoid harvesting when beans are driest, such as on hot afternoons, to maintain moisture and reduce shattering losses. Harvesting immediately after a rain, if field conditions allow, will result in higher moisture contents.  However, several wetting and drying cycles from rain events will make the soybeans more susceptible to shatter losses from pods splitting open.

    4. Avoid harvest losses from shattering by harvesting before the beans become overly dry. Four to five beans on the ground per square foot can add up to one bushel per acre loss. Many times, the dock for delivering beans over 13% moisture content may be less the shatter losses from harvesting overly dry soybeans.

    5. If there are green leaves and green pods in the grain, they are considered foreign matter at the marketplace which can result in dockage.  If placed in on-farm storage, they can cause challenges in a grain bin at the edges. Avoid dockage and spoilage by doing the following:
      • Reset the combine as outlined above to provide a cleaner harvest.
      • Use a grain cleaner to remove the foreign matter before marketing or storage.
      • Use a grain spreader when putting beans into storage to better distribute any foreign matter.
      • In storage, operate the aeration fan to dry the leaves and green pods to a safe storage moisture content. The pods and green beans will dry quickly and help rehydrate any overly dry beans. The fans need to be operated for temperature management anyway.

    6. Don’t place “all of your eggs in one basket” when it comes to selecting the maturity of soybean seed at planting time. Select your varieties and schedule your planting to spread out plant maturity and harvest. Plant your early maturing varieties first.

Good luck and hopefully you'll have a safe harvest and an excellent crop of 13% moisture soybeans

In addition,  some annual questions and answers exist regarding grain drying and storage.  I found this published back in 2009 and it seems the topics are quite relevant


Harvest  Grain Drying- Frequently Asked Questions

By Charles R. Hurburgh, Department of Agricultural and Biosystems Engineering—Iowa State University

Q.   When you encounter rainy weather during harvest, should we shut off fans and wait for the weather to improve?

A.  If you are drying with heated air, no. Keep the drying moving; in fact the rainy weather may be the only chance to catch up or keep up with the fast pace of wet grain once the weather improves. If you are drying with natural air, or are just cooling/holding wet grain, then it depends.  If the grain is reasonably dry (corn below 17 percent, soybeans below 15 percent), with uniform moisture and cool temperature (below 50F), then you can shut off the fans but remember to turn them back on. Otherwise no. You do not want to stop a drying or cooling front in the bin, and wetter grain heats so you need to keep control of temperatures. Grain picks up moisture from the air at about one-fourth the rate at which it dries so rewetting over short periods is not usually an issue.

Q.   When corn moistures are in the upper 20s or 30s and my dryer cannot keep up at all. What are options?.

A.  As we get into early October, there will likely not be much field drying any more. Recent rains can rewet some corn if the upright ears trapped water; sprouting in these cases may occur also. At this point, any choices are designed to buy time so that corn can be harvested, held and drying completed later. I will talk about elevator drying and shrink in another question. 

Natural air/low temperature will still work, although slowly. In most air drying bins (depth less than 20 feet), about 1 hp/1000 bushel will handle up to 20 percent moisture, 2hp/1000 up to 22-23 percent. Beyond that, fan horsepower becomes too large and spoilage risk too high. Natural air will not finish drying this fall.

Heated air drying can be speeded up by removing hot corn and cooling in storage. Consider drying very wet corn in stages – down to 24-25 percent; cool, hold with air, redry to below 20, then use air the rest of the way. This will buy some time but will take more management, effort and cost.  Producers and elevators with a combination of drying systems will find more options to move and hold grain to capture short term capacity.


Q.  Soybeans appear to be delayed in maturing.  What about wet soybeans and high temperature drying? 

A.   Soybeans react in storage like corn with 2 percent higher moisture – 15 percent soybeans respond about like 17 percent corn. Natural air is the best.  The goal in heated air drying should be either to get the beans to 14 percent, still able to be held overwinter with aeration, or to the acceptance moisture of the market.

Many markets cut off soybean acceptance at 15 percent moisture. Elevators are generally not designed to dry two products. The dryer, aeration and grain flow of wet material is usually arranged for corn only. In normal years, the few wet soybeans that are harvested are blended with the larger amount of dry beans. Some years, soybean maturity gets delayed and there are few dry beans to blend with. Crush processors cannot handle wet soybeans either; they are too soft to split correctly in the cracking rolls, which then makes the hulls (fiber) hard to remove.

Q.  Shrink and other charges for moisture seem to be going up. Why? 
Soybeans are the most subject to these increases because the commercial elevators do not have the capability to dry soybeans efficiently. There have been dryer fires as a result of soybeans in corn dryers. Farm drying systems, especially bin dryers are more suited to soybean drying.

Normally moisture is handled with a combination of shrink deductions of weight and fees for drying. Shrink is intended to calculate, as closely as possible, the ending weight after both drying and storage-handling operations. Equivalent bushels after shrink to the market standard moisture are used for settlements, warehouse receipts and their regulatory verification, and other production related needs such as proven yields, loan collateral, and insurance adjustments.

Shrink adjustments are made with a percentage deduction per percent of moisture. Drying (water) loss is mathematically fixed depending on the ending moisture (15 percent normally for corn and 13 percent for soybeans), and independent of starting moisture or grain condition. Drying to 15 percent removes 1.18 percentage point of moisture; drying to 13 percent removes 1.15 percent. The difference between these figures and the actual factor used by the grain buyer is an allowance for handling and storage loss. In Iowa, shrink must be disclosed as the sum of the water and handling percentages – e.g. the common 1.40 percent per point is 1.18 for water and 0.22 for handling allowance. The total handling allowance goes up with the amount of moisture removed.   Two points removed gives 0.44 percent in this case; 5 points removed gives 1.1 percent, and so on.

Scientific tests have shown that, overall, grain elevators actually experience about 1 percent loss during storage and handling, and that farm systems loose about 0.5 percent, beyond the moisture removal.  The normal shrinks taken by elevators (1.35 percent or 1.40 percent) allow about enough handling loss at typical harvest moistures, with progressive increases for the less typical and more difficult-to manage higher moistures.

Problems arise when shrink factors are used as discounts or incentives beyond inventory weight balance. To keep accuracy in inventory and in other non-market uses of production data (such as proven yields, crop insurance settlements, and loan collateral), shrink should be used for weight only. There is no restriction in Iowa on either the shrink scale used or on the drying/handling fees that can be imposed to provide incentives. Recently soybean shrinks as high as 3.0 percent per point (1.2 for water and 1.8 for handling loss, per point) have been seen.  These are discouragements to high moisture beans, but will result in significant “long” inventories, from beans present but not listed on settlements.

Financially, the producer and elevator may end up in the same place with a high shrink or a lower shrink plus higher fees for drying, but producers needing accurate quantities for production records should discuss with buyers how to get weight records reflective of the actual dry bushels delivered. At 20 percent moisture dried to 13 percent, the 3.0 percent scale deducts 21 percent of the weight; 8.4 percent for water and 12.6 percent for handling losses.

Drying charges normally range from 4-6 cents per bushel per point of moisture, and must cover both the variable cost of dryer operations (fuels, labor, etc.) and the fixed cost return to the dryer investment. Farm dryers may dry at lower costs for variable costs only, but when the fixed cost of the dryer is included, total costs are often similar.


Charles Hurburg,  professor of Agricultural and Biosystems . He can be contacted at (515) 294- 8629 or by email at tatry@iastate.edu.


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