September 1997
Wheat and Barley Production Tips
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Prairie Grains is the
official publication of
the Minnesota
Association of
Wheat Growers,
North Dakota Grain
Growers Association,
South Dakota Wheat,
Inc., and the
Minnesota Barley
Growers Association.
by Jochum Wiersma, U of M Small Grains Specialist
By the time you read this we should pretty much know how bad scab hit us again this year. At the time I am writing this (end of July) I have turned from slightly optimistic to downright pessimistic. Writing about anything else but scab may seem inappropriate at this time, but there are other timely facets of profitable small grains production we should touch on.
WINTER WHEAT
The first two weeks of September are the time to plant your winter wheat. The latest date should really be the second week in September around these parts of the world.
Winter wheat takes up only a sliver of acreage in our northern-growing area (and for good reason; primarily the very fact that we are in a northern-growing area). Some farmers, however, have shown an interest in winter wheat for a multitude of reasons. The two most common heard arguments are: 1) Distribution of labor and machinery, resulting in ability to farm more acres with the same equipment, and 2) Escape from scab.
The first argument indeed holds some water. In most years winter wheat can be planted following the small grains harvest. Since there are fewer and fewer acres in summer fallow, the question arises whether to plant the wheat back into a wheat or barley stubble. If at all possible, try to avoid that scenario. Winter wheat will get off to a faster start than many weeds, and thus reduce herbicide costs, but the flip side is that the winter wheats that are available to you can be susceptible to leaf diseases like Septoria leaf spot and/or tan spot, so plan on shifting those herbicide savings to a larger fungicide bill.
The biggest problem we have with growing winter wheat in the northwest part of the state is winter kill, which can reduce stands to nothing. Snow cover is essential to minimizing winter kill. In many years the winter kill is worst in late March/early April. Warm weather melts the snow and breaks the dormancy of the winter wheat. If the warm spell ends and cold weather returns to the region, the growing plants are much more susceptible to damage from frost.
Northern growers are interested in winter wheat based on the premise that it will develop (flower) earlier, and thus escape the 1990s weather cycle that has resulted in wet Julys and scab infections in spring wheat. However, currently available winter wheat varieties are not resistant to scab or even very tolerant to the disease. The University of Minnesota does not have any official ratings on any of the varieties that are available, but preliminary work indicates that all could be rated as susceptible. Winter wheats generally head about two to three weeks earlier than spring wheats. These three weeks may allow the crop to avoid weather that favors the development of scab (then again, it may not).
There are five public winter wheat varieties available. Roughrider, Seward, and Elkhorn are rated as very winter hardy. Arapahoe and Rose are rated as winter hardy. All except Roughrider are at least moderately resistant to stem and leaf rust. Arapahoe and Seward have proven the top yielders in the past few years, both with lower protein and good test weights. For additional information, I encourage you to check the Variety Trial data at: http://www.mes.umn.edu.
GRAIN DRYING AND STORAGE
Proper drying and aeration of stored grain is important in maintaining the quality of your harvested grain. Someone once told me that the quality of most wheat is great until you put it in the bin. I think that is too bleak of a picture, but you do need to make sure your bins are ready to go, and stored grain is properly managed. Prior to loading any grain into a bin you better make sure the bin is cleaned out and free of any old (moldy) wheat/barley and insects. The first step in preventing storage insects is to make sure you didn't have any to begin with.
If you decide to harvest your grain on the wet side, you need to bring down the moisture content to around 13 to 14% moisture to allow for long term storage. Drying grain can be done either by natural air or by forced heat. NDSU Extension Educator, Dr. Keneth Hellevang, has written two small articles about grain drying which are below.
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 degrees Fahrenheit, for 16% moisture content; 140 degrees for 20% initial moisture content; and 120 degrees 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 degrees, Fahrenheit, 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 degrees, Fahrenheit, 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 degrees.
ADDITIONAL GRAIN DRYING FANS NOT NORMALLY APPROPRIATE
To double the quantity of airflow for grain drying requires about five times the horsepower. To achieve an airflow rate of 0.5 cfm/bu requires a 3-3.5 hp fan, an airflow rate of 1.0 cfm/bu requires a 15 hp fan through a 21 foot diameter bin filled 17.5 feet deep with wheat.
A diminishing return for adding fans is quickly reached. A single 7.5 hp fan provides an airflow rate of 0.86 cfm/bu, two fans provide an airflow rate of 1.20 cfm/bu (a 40% increase), three fans provide an airflow rate of 1.45 cfm/bu (an 8% increase), and five fans provide an airflow rate of 1.62 cfm/bu (a 3% increase).
The cost for drying wheat from 17% to 13% with $0.06/Kw-hr electricity is about $0.065/bu with one fan, $0.094/bu with two fans, $0.117/bu with three fans, $0.143/bu with four fans, and $0.174/bu with five fans. The cost increases because the drying time is only reduced from 27 days to 14 days, while the horsepower increases from 7.5 to 37.5 hp as additional fans are added.n