WW-06959-GO May 1, 1997Vol. 3, No. 7
Copyright © 2002 Regents of the University of Minnesota. All rights reserved.
This is a special edition of Minnesota Crop News, the newsletter of the University of Minnesota Extension Service's crops system team. This special edition emphasizes the direct and indirect effects of flood on crop production in northwest, west-central, and south-central Minnesota. We hope that the information provided in this newsletter will be helpful and that you will contact your county Minnesota Extension Service office for further cropping resources.
|For more information contact Extension Plant Pathology at (612)625-6290|
Producers working in and cleaning up previously flooded areas will likely be exposed to unique hazards that could lead to serious injury or even death.
Be extremely wary of electrical equipment that has been exposed to flood water or other moisture. Don't turn the power back on until it has been inspected by a qualified electrician. Unless you are certain that the power is off, never enter flooded areas or touch electrical equipment if the ground is wet. NEVER handle a downed power line.
Flood cleanup may involve the use of gasoline or diesel powered pumps, generators, and pressure washers. Because these devices release carbon monoxide, a deadly, colorless, odorless gas, operate all these devices outdoors. NEVER bring them indoors. It is virtually impossible to assess adequate ventilation.
Tractor and equipment operators should be extremely cautious when using towing chains to free or move "stuck" equipment. Hitch only to the drawbar to avoid tipping the tractor over backwards. Never use a nylon rope -- several fatalities have occurred in recent years when ropes, clevises, or hooks break, turning the tow rope into a deadly sling-shot. Only use a long towing chain designed to support the towed load. Check the machine's operator's manual for additional safe towing information.
[In This Issue]
The average date full-scale fieldwork is expected to begin in Minnesota this year is April 29, according to the Minnesota Agricultural Statistics Service. The Northwest District, which produces much of the state's spring wheat and barley, and a large portion of the sugarbeets, potatoes, edible beans and other crops, will see a much later average start-up.
At some point, producers will need to decide whether to shift to an alternative crop, or even to idle the land for the 1997 growing season. It is important to focus on the variable or "relevant" costs -- those costs which will vary or only be incurred if the crop is planted this year. Although it is difficult to put them out of your mind, costs already incurred are "sunk" or "irrelevant" and should not enter into the decision.
Relevant costs might typically include seed, fertilizer, chemicals, fuel and labor for machine operations. These costs should be compared against the reduced yields expected with planting delays. Some costs which are probably irrelevant at this point are machinery depreciation and interest, and land ownership and rental expenses.
If an alternative crop involves a change in machinery operations from what you are used to, you may need to estimate operating costs or negotiate custom rates. If so, publications which may be of assistance are FO-6696, Minnesota Farm Machinery Economic Cost Estimates for 1997, and FS-3700, Minnesota Farm Custom Rate Survey. Both are available from your county extension office and on the University of Minnesota Extension Service web site.
The decision to switch crops may be easier to analyze if you set up a computer spreadsheet which starts with the relevant costs for the crop, and then calculates the return per acre over a range of yields and prices. Some average costs and yields per acre for common Red River Valley crops, from the 1996 annual summary of the Northland College Farm Business Management Program at Thief River Falls, are shown below. Most relevant costs for this year's cropping decisions are included under "direct expenses" such as seed, fertilizer, and chemicals. Land rent is included in direct expenses, so direct expenses tend to be higher on cash rented land. Overhead costs such as depreciation and interest on long term debt are added to direct expenses in the "total expenses" column:
|Direct expenses per acre||Total expenses per acre||Yield per acre|
|Spring wheat on owned land||$ 95||$150||43.5 bu|
|Spring wheat on cash rented land||148||173||45.9 bu|
|Soybeans on owned land||89||158||31.2 bu|
|Soybeans on cash rented land||145||175||29.8 bu|
|Sugarbeets on owned land||384||581||17.9 tons|
|Sugarbeets on cash rented land||479||610||18.3 tons|
|Seed potatoes on cash rented land||557||703||133 cwt|
An example spreadsheet table is shown below, for spring wheat net returns per acre over relevant costs with a range of yields and prices. Relevant costs are assumed to be $100 per acre in this example. We recognize that there are also another $50-75 per acre in overhead costs which will be incurred regardless and irrelevant to this year's cropping choice, so we don't include them in the table. New crop wheat is in the $4.50-4.75 range. At these prices, it would still pay to plant in the example if you expect a yield of 25 bushels or more.
|Wheat price/bu||Wheat yield per acre|
[In This Issue]
Wheat and barley are both cool season grasses. This means they grow best between 50 and 70° Fahrenheit and swelter when temperatures creep above 85°. We plant spring wheat and spring barley as early as possible to try to escape the summer heat as best as possible.
Delayed planting due to adverse spring weather conditions thus poses a problem. Optimum and last recommended dates for planting wheat and barley for the different regions of northwest Minnesota are given below. These are based on the expectation that average temperatures increase as the season progresses. If we end up with a "cool" summer, the crop can have an excellent chance of succeeding despite a late planting date.
Planting dates in northwestern Minnesota. First date is optimum, second is last recommended.
|Fergus Falls||to||Breckenridge (Hwy. 210)||2nd Week of April||-||2nd Week of May|
|Detroit Lakes||to||Moorhead (Hwy. 10)||3rd Week of April||-||3rd Week of May|
|Mahnomen||to||Halstad (Hwy. 200)||4th Week of April||-||4th Week of May|
|Grand Forks||to||St. Hilaire||1st Week of May||-||1st Week of June|
Because of expectations that average temperatures will be higher as we plant later, development of the crop will speed up too. The number of heat units required for a plant to move to the next phase of development will accumulate faster. This forces development along farther and causing the plant to have less time to grow. Plants end up with fewer tillers, smaller heads, and fewer and smaller kernels per head, cutting into our yields.
Compensate for this expected loss by increasing seeding rate to ensure having more main stems per unit area. This will compensate for the expected yield loss. The general recommendation is to increase the seeding rate by 1 percent for every day after the optimum time frame.
And remember, when calculating your seeding rates -- calculate the number of units of seed you need per acre rather than the volume in bushels. To calculate your seeding rate you need to know the number of seeds per pound or 1,000 kernel weight in grams, the percent germination of the seedlot, and the anticipated stand loss in your field.
desired number of plants per acre /
(percent germination x [1-expected standloss])
number of seeds per acre /
number of seeds per pound
The last possible date for planting is not chisled in stone. The chances of a profitable crop just drop because of the anticipated weather and temperatures later during the growing season. The experiences some of you had in 1996 with excellent late-seeded wheat and barley crops should be considered an exception rather than the rule.
Past the last possible date, you may want to consider an alternative crop, though economic reality might prevent this. If you stay with wheat and barley past that date you will have to hope for a cool and dry summer.
Jochum Wiersma, Small Grains Specialist
Northwest Experiment Station
[In This Issue]
With delayed planting due to flood conditions, you will notice an impact on weed emergence patterns. The later the planting, the more likely you will notice this effect. For example, when small grains are planted early, wild oats are often a problem, however, as planting dates are delayed foxtails become a greater concern than wild oats.
A new publication, FO-6958 Relative emergence sequences for weeds of corn and soybeans, by Doug Buhler, USDA/ARS; Bob Hartzler, Iowa State University; Frank Forcella, USDA/ARS; and Jeff Gunsolus, University of Minnesota, addresses the relative emergence patterns of common weeds of summer annual crops. It is available now from the University of Minnesota Extension Store, and should soon be available through county extension offices.
The publication describes how weed emergence timing influences weed management systems and includes preliminary rankings of relative emergence for important weed species based on research data and observations of weed scientists in our North Central Region. Emergence sequences are ranked as group 0 (previous fall), groups 1 and 2 (prior to crop planting; early spring), groups 3, 4 and 5 (about the time of crop planting), and groups 6 and 7 (after crop planting; late spring). Some representative weeds from each grouping are:
Group 0: Horseweed/marestail, biennial thistles. Group 1: Kochia, wild mustard, Russian thistle. Group 2: Quackgrass, giant ragweed, Pennsylvania smartweed, wild oats. Group 3: Common ragweed, wild buckwheat, woolly cupgrass. Group 4: Giant foxtail, Canada thistle, common cocklebur, redroot pigweed. Group 5: Green foxtail, yellow foxtail, barnyardgrass, wild proso millet. Group 6: Black nightshade, common sunflower, waterhemp. Group 7: Crabgrass, fall panicum.
These rankings are estimates of emergence sequence. A species could easily shift one category in either direction, depending upon environment and management practices. Rankings are based primarily on differences in initial emergence and do not consider length of emergence period.
Jeffrey L. Gunsolus
Extension Agronomist/Weed Science.
[In This Issue]
Flooded fields, wet conditions, and the possibility of delayed planting will cause problems for some growers. Fortunately, only a few changes may be needed in weed management.
With the recent development of several new postemergence herbicides, growers no longer need to rely on soil-applied herbicides for weed control. Therefore, in fields that have been wet and where delayed planting will occur, growers should plant as soon as possible and plan on using a postemergence herbicide for weed control. In small grain, this will not cause any significant problems, as more than 90 percent of the herbicides used in wheat and barley are applied postemergence.
Delayed planting may cause a shift in weed species. The later the planting, the more likely that you will notice this effect. For example, when small grains are planted early, wild oats are often a problem; as planting is delayed foxtails become a greater concern.
In flooded fields, growers should also expect weed species that may not have been in the field before due to weed seed movement in flood waters. Growers should scout fields and identify and map any new weed infestations. Local sources such as county agents, Vo-Ag instructors, or agricultural inspectors can help with the identification of new weeds.
If there is a weed identification problem that cannot be solved locally, you can follow the instructions below and mail the plant specimens to:Beverly R. Durgan or Kevin Cavanaugh
DO NOT put weeds into plastic bags or wrap in plastic wrap. The plants will turn to mush.
Information on weed management, herbicide application, and timing is available in the MES publication BU-3157 Cultural and Chemical Weed Control in Field Crops--1997, available in county extension offices.
Beverly R. Durgan
Extension Weed Scientist
[In This Issue]
Small grain producers in northwest Minnesota are anxiously waiting for dry soils to begin spring planting. For many producers, excessive wet soils from flooding will delay planting, effect soil applied herbicide efficacy and very likely influence choice of crop planted. The rush to get Far-Go (triallate) or Treflan (trifluralin) herbicides applied and incorporated, and the crop planted, may tempt some to take short cuts which may result in a lack of wild oat and foxtail control.
Cold, wet soil can cause delayed emergence, stand reduction, stunting and yield loss. Potential for crop injury increases under cool, wet soil conditions with these two herbicides. Spring planted grains will emerge slowly in these soil conditions resulting in a longer contact period with soil applied herbicides. Also, the combination of these two herbicides has a greater potential for crop injury than when either is applied alone. The following guidelines can minimize crop injury:
Cold temperatures prevent triallate from changing to a gas form. Wet soils prevent triallate from filling soil pore spaces because they are already filled with water. If wild oat and other susceptible weeds germinate during this time, triallate may not be in an active form (gas or vapor) and poor performance may result. Fall applications of granule herbicides usually are more consistent than spring applications. Fall applications allow more time for the herbicides to equilibrate in the soil, giving them time to be in a gas form, positioned to intercept weed emergence.
Herbicide efficacy will increase as soils warm and dry out in the germinating weed zone. Weeds that emerge through the soil applied herbicide zone will require a postemergence application for control. Delayed planting this spring may cause many growers to forgo any spring applications of soil applied herbicides because the wild oats and foxtails will have already emerged by the planting date.
If fall applications of Far-Go, Treflan or Buckle were made and wet soils from spring flooding delay your spring grain planting beyond mid-May, some alternative crops can still be planted. These alternative crops are soybean, dry bean, sunflower and alfalfa.
Kevin Cavanaugh, Agronomy & Plant Genetics
Beverly Durgan, Extension Weed Scientist
[In This Issue]
Wet conditions and the possibility of delayed planting create problems for Valley growers as May arrives. However, few changes in disease management are recommended as small grain planting approaches. Seedling diseases should not present unusual management concerns even in fields where water has been standing, provided that conditions immediately after planting are favorable for seedling growth.
For the most part, environmental conditions that favor disease will be determined after planting. Seed treatments will benefit poorer germinating lots and should be considered if alternative seed sources are not available. Delayed planting may place fields at risk for certain virus diseases (Barley yellow dwarf, wheat streak mosaic and others).
Scab will likely remain a significant concern this year. Along with planting resistant varieties, rotation and pre-plant tillage to remove infected debris are the best methods to minimize losses.
Overall yield effects will be a function of temperatures during July and August, and a good crop may still be possible. The best advice is to remain calm, continue with your normal practices and allow time for good seedbed preparations. Increasing seeding rate will be beneficial.
Roger K. Jones
Extension Plant Pathologist
[In This Issue]
Normal planting dates for soybean in Minnesota are typically after corn. In recent years, increased yields due to early planting has advanced the recommended planting date for both crops. According to the Minnesota Agricultural Statistics Service, about 5 percent of soybeans are now planted by May 10th, nearly 50 percent before May 20th, and about 95 percent by June 15th.
Early planting allows full season varieties which are usually higher yielding than earlier maturing types. Yield performance and other characteristics of the major public varieties for various planting dates in Minnesota are reported in the Soybean Variety Trials: 1997 report, published by the Minnesota Agricultural Experiment Station.
Table 1 shows the approximate percentage yield loss resulting from various planting periods. Note that plantings earlier than May 20 produce the best yields, while later plantings result in large yield decreases. Full season varieties planted before June 10 can mature in southern Minnesota before the fall frost date in early October, but will have reduced yields.
|Planting Period||Yield Loss (%)|
|Late April to Early May||0|
Table 2 lists recommended public varieties for various maturity areas and planting periods in Minnesota. Following these recommendations should ensure a harvestable grain of good yield and quality. This table can help you in selecting varieties for late planting following a natural hazard such as flood damage or other reason. If planting is delayed too long into the growing season, soybeans may not be economical, so you might have to switch to another crop.
|Planting Period||Variety Recomendations|
||Northern||North Central||Central||South Central||Southern|
|Until Mid-May||McCall,Agassiz||Agassiz,Ozzie||Ozzie,Lambert||Lambert, Parker||Parker, Sturdy|
|Until Early June||McCall||Agassiz,Ozzie||Ozzie,Lambert||Lambert, Parker||Parker, Sturdy|
|Until Mid-June||---||McCall,Agassiz||Agassiz,Ozzie||Ozzie, Lambert||Lambert, Parker|
|Until Early July||---||---||McCall,Agassiz||McCall, Ozzie||Agassiz, Lambert|
Leland Hardman Extension Agronomist-Crops
[In This Issue]
Cool season perennial grasses have more flood tolerance than cool season legumes. Most of the flooding in Minnesota has occurred before these plants broke winter dormancy. The data in the table below cites flood tolerance for species exposed to early flooding. Plants that have not broken dormancy may tolerate more flooding than this table indicates. These perennial plants will not tolerate more than a few days of flooding during summer except reed canarygrass or creeping foxtail.
Th source of the information in this table is a publication from North Dakota's Cooperative Extension Service (Duaine Dodds and E. H. Vasey. May 1974. Forages For Salt-Affected and Wet Soils. Circular R-584. Cooperative Extension Service, North Dakota State University. 4 pp.).
|Garrison creeping foxtail||35 1|
|1 Estimated based on tolerance of meadow foxtail.|
Neal P. Martin
[In This Issue]
If ice sheets damage alfalfa, the damage occurs from a smothering effect. Such damaging ice sheets must completely seal the surface above alfalfa plants and the bottom of the ice sheet must come in close contact with alfalfa. By sealing the alfalfa plants away from air, a build-up of carbon dioxide occurs below the ice sheet killing alfalfa crowns and roots. Field observations which show stems above ice sheets do not fit a "sealed condition."
Excessive sub-zero temperatures, cold enough and long enough air temperatures to cause a 5 to 15 F temperature at 2 to 4 inch soil depth (region surrounding alfalfa crowns) for longer than 2 weeks will also kill or severely damage alfalfa plants. This temperature effect has not been observed in Minnesota this year. Temperatures on the soil surface have been relatively warm, which should reduce otherwise expected damage in southwest Minnesota from ice sheets deposited earlier this fall. Therefore, extensive damage of alfalfa from ice sheeting may not occur.
Red clover, birdsfoot trefoil, white clover, and alsike clover may not tolerate as much ice sheet smothering as alfalfa. Expect grasses to tolerate more ice sheeting than alfalfa because of the difficulty of creating a 'soild' ice sheet. Of the cool season grasses, orchardgrass and tall fescue will have less winter hardiness than smooth bromegrass, reed canarygrass, Kentucky bluegrass and timothy.
For alfalfa, regardless of our expectations from flood or ice sheet damage, farmers need to observe regrowth after the flood waters clear and warmer temperatures arrive. If regrowth comes and comes very even, you had no damage. If regrowth is variable, dig plants to ensure roots are not rotting and continue to observe growth until plants grow through a 6-inch plant height, the height when you can be certain plants are recovering. If plants don't green-up, ice sheets or flood waters smothered them out.Neal P. Martin Extension Agronomist-Forages
[In This Issue]
A few counties have been keeping haylist programs on their own. The Minnesota Extension Service is developing a haylist for the MES homepage patterned after the Greatlakes haylist which was run by University of Wisconsin Cooperative Extension and MES. When this service will be available is not yet known.
The Internet Hay Exchange (www.hayexhange.com/hay.htm) lists hay by state and county within the state. The service is free and as of Friday afternoon, April 25, 1997, a couple of listing are on the system. There are several listing for 1997 crop.
Neal P. Martin Extension Agronomist-Forages
[In This Issue]
According to recent University of Minnesota trials, canola is a cropping option available for northwest Minnesota that can be seeded in late may/early June and still provide respectable yields. Spring canola is a cool season crop and will do well in cooler springs and when temperatures are cooler during flowering.
Growing degree-days required for canola Brassica napus(Argentine types), are similar to spring wheat. Canola seedlings will usually recover from a light spring frost that does not damage the growing point of the plant. Early seeded canola, after several days of near freezing temperatures, will undergo a gradual hardening process that will withstand freezing temperatures without serious damage. In Canada early planted canola that had undergone hardening withstood 18° Fahrenheit temperatures while later planted canola which did not undergo hardening was killed at 27°.
Late planted canola can be injured by hot temperatures during flowering by setting fewer pods, especially when hot temperatures are combined with dry conditions. In many cases however, the plants will set additional pods after a short, hot period.
Considerable planting data for canola is available from Canada but limited planting data is available for northern Minnesota. Our only data is from 1996, which was a late, wet year, with our earliest planting date in late May. We planted six varieties (two each of early, midseason and late) on four dates near Crookston and Roseau. Table 1 and Table 2 present the yield and other data. Plantings at Crookston were May 28, June 8, June 18 and June 28. Plantings at Roseau were May 29, June 8, June 18 and July 3.
The relatively cool year in 1996 resulted in very good yields for the late May plantings. Yields were reduced by about 20 percent for the early June plantings, but were respectable. If the season is late and cool again in 1997 we would expect similar results.
|1 Days after planting|
||Date 1||Date 2||Date 3||Date 4|
|1Hysyn 110 and Reward are early; Hyola 330 and Topscore are mid-season; Crusher and Global are late.|
Ervin A. Oelke
[In This Issue]
If your season is late due to flooding and cool, wet conditions, the table below can be referred to for normal planting range of dates and risk dates for some of the specialty crops.
|Crop||Risk due to early planting||Normal Range||Risk due tolate planting|
|------- Dates -------|
|Flax||--||April 22-May 7||May 8-June 10|
|Proso Millet||May 5-May 15||May 16-July 15||July 16-21|
|Dry Bean||May 15-May 21||May 22-June 17||June 18-21|
|Buckwheat||--||June 7-July 15||--|
|Sunflower||May 1-May 10||May 11-May 25||May 26-June 7|
|Mustard||--||May 1-June 15||--|
|Sudan||--||May 25-June 15||June 16-June 30|
The risk for planting early is frost, or soil-borne pathogens which overtake seedlings in cold soils. The risk of late planting is usually frost before the crop can mature. Also, late seedbeds are sometimes dry and do not provide satisfactory stands.
Specific information including history, uses, growth habits, environmental requirements, cultural practices, yield potential in Minnesota, economics of production and markets, and information sources on the above and 40 other crops is in the Alternative Field Crops Manual. All county offices have copies for reference. The complete manual is available for $45.00 from:Center for Alternative Plant and Animal Products
Ervin A. Oelke
[In This Issue]
Grain bins exposed to flood waters are likely to have sustained damage and some grain loss can be expected. It is, however, often possible to repair bins and salvage at least part of the grain.
Water does not "wick" very far in whole grain, so it is likely that grain above the water line is still in good condition. It might even be possible to salvage grain that was submerged in flood waters, but quick action will be required to prevent spoilage of this very wet grain.
Actions necessary for salvaging flood-damaged grain depend on the extent of damage to both bin and grain, so the first step is to inspect the bin, including unloading and aeration equipment, and the stored grain. Then, contact your insurance company or disaster relief agency as soon as possible to find out what you need to do to document losses.
Here are answers to some potential questions about flooded grain bins:
Another option is to dry the wet grain in a gas-fired dryer. Energy costs for on-farm drying will be 1-1.5 cents per bushel percentage point of moisture removed. Commercial drying charges will probably be 2-3 cents per bushel per point.
If you can remove the dry grain from the top of the bin and get the fan going, you might be able to use unheated air to dry wet grain in bins equipped with full perforated floors and large drying fans. Chances of success for unheated air drying decrease as grain moisture, outside temperature, and grain depth increase. If the grain is much wetter than 20 percent moisture, don't use this drying method for more than about six feet of grain.
Under certain conditions, grain molds can produce mycotoxins that can cause animal feed refusal, health problems, or even death. Since beef cattle (except for breeding stock), are somewhat less sensitive to molds and mycotoxins than other animals, feeding suspect grain to beef cattle as part of a mixed ration would be safer than feeding to other animals. If grain develops a lot of visible mold, test for mycotoxins before feeding it or spending money to dry it. Grain that is badly damaged by mold or has high levels of mycotoxins should probably be discarded.
If the water line was below the level of the side door on the bin, it might also be possible to insert an auger into the dry grain through a small opening in the side door. Make sure the auger extends to near the center of the bin, however, because unloading a bin from one side creates uneven sidewall pressures that can damage the bin.
Drying, aeration, and unloading equipment on bins is likely to be inoperable immediately after floods. In many cases, however, motors, controls and gas burners will work again after being cleaned and dried. Don't start electric motors until they have been cleaned and dried or they might burn out. Also clean mud and debris off of fan blades to prevent imbalances that might lead to bearing damage. In many cases, aeration ducts and areas under full-perforated floors will contain mud and saturated grain fines. Clean these areas before next season.
Companies that work on grain bins will be busy this year, so if repair work is needed, try to line up a contractor as soon as possible to get bins repaired before next harvest.
If grain rests directly on a concrete floor, it is possible that water moved up through small cracks and pores and wet a few inches of grain next to the floor. It is also possible that in- floor aeration ducts are full of water and mud and that the fan and unloading system have been damaged by water. If you can get the aeration system to work, attempt to dry the layer of wet grain by aerating it. Or, if you can get the unloading system to work, consider transferring grain from one bin to another to get the layer of wet grain off the floor before it molds.
Note that chemically treated grain can neither be fed to animals nor sold in normal commercial channels.
[In This Issue]
A study was made of one bin of wheat and one bin of barley shortly after the Red River Valley flood of 1979. This was done to determine storability changes in the grain above the water level in the flooded grain.
The study was done on grain in a small 5,000 bushel flat storage bin. The bin was divided in the middle with the barley stored on the east half and wheat stored on the west half. Deep probes were taken on one of the several peaks in each half of the bin. Temperature readings and samples for mold analysis were taken at various depths. Temperature probes were also taken around the edges of the pile to detect the hot spots.
Water had reached a level of 1 foot in the bin. It was flooded on April 23 and the water was present until May 3. Samples and temperature readings were taken on June 6. The submerged portions of the grain were under water for 11 days and samples were taken 45 days after the flood started, which was 34 days after the water receded.
The first foot of grain was solid with mold and heating to temperatures of 95 to 115o Fahrenheit. Temperatures within the rest of the bin ranged from 6o to 90o. Warmest areas in the bin, outside of the moldy layer at the bottom, was at the grain peaks. High temperatures in these peaks indicate fungus activity due to moisture migration, a natural movement of moisture that occurs any time there are temperature differences within a grain bin. Heat at the bottom indicated continuing spoilage due to the flood water.
Mold and moisture analysis determined moisture content ranged from 10.4-17 percent. Areas with poor storability were in grain peaks and near edges of the pile where grain was only 2-3 feet deep. These areas had moisture contents of 14-17 percent and were infested with high amounts of storage molds.
This study indicates that when the bottom foot of grain in a bin is soaked with flood water, grain above will begin to deteriorate but could last at least 30 days at May temperatures in Minnesota. Active hot spots in the periphery of the bin indicate damage would occur in these aresa in 1-4 weeks. Moisture migration will also cause molds to spoil the grain in the peaks within 1-4 weeks at the reported temperatures.
To prevent moisture migration and subsequent spoilage, remove the dry grain from the bin as soon as possible. If the grain wet by flood water is removed before spoilage, and is not otherwise contaminated, it may be salvaged by drying or ensiling. If this wet layer molds it could be disposed of by spreading on a cropped field.
Feeding moldy grain to livestock carries risk because of possible mycotoxin problems. If moldy grain is to be used in feed it should be fed to beef cattle (not breeding stock) as part of a mixed ration, as they are usually less susceptible to low levels of mycotoxins. Studies show substantial nutritive changes in moldy grain which will affect nutrient content of mixed rations.
Richard A. Meronuck Extension Plant Pathologist
[In This Issue]
Some of the most fertile soils in the world are those that flood regularly. Most fields that have flooded this spring should have the same fertility status as they did before any flooding, but these flooded crop fields will have an extra thin layer of soil this spring. This new layer of sediment (soil) will mainly contain clay, along with some silt, and could be considered beneficial rather than detrimental.
The exception to the beneficial potential is in the northern Red River Valley where significant overland flow occurred. This created new (water flow) channels in some agricultural fields that would result in the removal of topsoil in these areas. Such areas will be very visible as the flood waters recede.
The majority of the sediment in flood waters comes from stream banks, although this year's overland flow situation also contributed significant sediment. When creeks, streams, and rivers flood, the energy contained in the increased flow of water causes sediment on the banks to erode and move with the water. The amount of additional sediment coming from flooded fields will depend on tillage system, soil slope, previous crop, and amount of water flowing across those fields.
Flood waters often appear orangish-brown. The color is from soil sediments suspended in the water. These sediments will settle out as water flow rate decreases. Sediments consist of sand, silt, and clay particles. Bigger particles (sand) do not move very far in water unless the flow rate is fast, such as in the center of a creek, stream, or river. The smallest particles (clay) can stay in water for long periods of time and take days or weeks to settle out of even calm water.
Flooding of most agricultural fields is away from the main water flow, where the water has a slow flow rate. This means that deposition of sediments (clay and some silt) is more typical on fields than erosion.
The layer of deposition is a function of the length of time the field was flooded, the amount of sediment in the water, and the rate of flow of the water across these fields. In most cases this layer is visible and can measure up to a fraction of an inch. However, because this represents a relatively small amount of soil added compared to the entire topsoil quantity, soil tests that were taken last fall will still be representative of the fields and should be used in making fertilizer recommendation.
Mike Schmitt, Extension Soil Scientist
Mark Seeley, Extension Climatologist
[In This Issue]
Delayed plantings generally result in decreased yields for small grains and corn. A shorter growing season, probability of frost, fewer heat units, less tillering, summer's heat and moisture stress, etc. all contribute to reduced yield potential.
Expected yield, or yield goal, is a key component in all N, P, and K crop fertilizer recommendations. These are made by combining a soil test value of what is or will be available in the soil and what is needed by the crop, which is a function of yield level. Therefore, if a delay in planting is imminent, fertilizer recommendations can also be reduced.
University of Minnesota fertilizer recommendation tables generally group yield goals by 10 (small grain) or 20 (corn) bu/acre increments. This grouping may be deceptive if one was planning on a 59 bu/acre wheat yield and predicts a 15 percent yield loss, because the same N recommendation would be given (the yield goals of 59 and 50 are both in the same grouping). Our recommendations are most accurate for the midpoint yields of these groupings.
For fertilizer programs that already have the nutrients applied from a previous application, the P and K will still be there and should not be a concern. For previously applied N, remember that the rate originally applied was based on an expected yield goal that will probably be lowered due to delayed planting. Thus, some N losses can be tolerated due to the reduced yield goals.
Extension Soil Scientist
[In This Issue]
"Stay off wet soil" is the primary recommendation for keeping soil compaction problems to a minimum. Following this recommendation will be a major challenge for farmers in areas that have received record snowfalls and have high soil-moisture. Some planting on wet soils may be unavoidable.
If tilling and planting are going to take place on wet soils, it is important to minimize compaction caused by wheel traffic and tillage. This requires proper ballasting of the tractor, using appropriate tires and tire pressure, avoiding unnecessary field operations, and maintaining tillage equipment.
Tire pressure should be at recommended levels. High pressure will cause compaction; low pressure can result in tire damage. Radial tires cause less compaction than bias tires, especially when the tire pressure is correct. Note that recommended tire pressure is lower for radial tires than for bias tires. Larger diameter tires cause less compaction because of a larger tire print in the soil. Concern about compaction is a primary reason for recent availability of larger tires. Dual tires will also reduce compaction at the soil surface, compared to single tires.
Minimizing the number of implement passes through the field reduces compaction. Evaluate the cost of each tillage pass compared to expected increase in yield that results from the operation. Many producers disk or field cultivate two times before planting; it might be possible to eliminate one of these operations with no yield loss.
Worn or dull soil-engaging tools on tillage equipment, such as chisel plow shovels and disks, will cause more compaction than new tools. Planters and tillage equipment should be level from front to rear. When not operating level in the field, they require more draft and power, and additional ballast is needed to keep wheel slip in the correct range.
Ron Schuler, Extension Engineer
University of Wisconsin
[In This Issue]
Patience is a must when it comes to seedbed preparations, especially when we are looking at a late spring. The temporary submergence of fields and the deposition of sediments may have destroyed soil aggregate structure, including macropores, as a result of fall tillage. These conditions may also have produced a good deal of surface sealing. Secondary tillage and proper seedbed preparation may be especially important prior to planting on these fields.
Seedbed preparation attempts to create optimum conditions for germination and healthy vigorous seedlings, and a good stand is crucial for maximizing yields. Without a good stand, all other inputs are less effective, or even a waste.
Tillage of wet soils can cause loss of soil structure, compaction, clumping, and poor seed-soil contact. Subsequent seedling emergence would be uneven, with reduced plant stands, and preplant herbicides may even get incorporated poorly.
Although little research is available, cold and wet soils increase the potential for root diseases. Excess moisture creates an almost anaerobic condition. Germinating seeds need oxygen to grow, and anaerobic conditions weaken the developing seedling making it more susceptible to root diseases. Average soil temperatures need to be above 42° Fahrenheit before the germination process for wheat and barley can even start.
Delayed planting comes with a yield penalty because of the shorter growing season that is left, making an optimum stand even more important. Waiting one or two days can make a large difference when it comes to seedbed preparation.
Jochum Wiersma, Small Grains Specialist
Northwest Experiment Station
[In This Issue]
A concern for many producers this spring is the fate of nitrogen applied last fall. Since last fall, many events have happened that are creating a concern for this N -- an early freeze last fall, early (and deep) snow cover for some, a brutal winter, a cold spring, and a wet to flooded late winter/early spring for some. As long as the soils are or were cold, N conversion to nitrates, and loss to the air via denitrification, is greatly reduced.
While N losses have not likely occurred yet, there is reason to be concerned for the coming weeks. As soils continue to warm, fall-applied N will eventually all convert to nitrate-N. This is when everyone needs to be aware of soil moisture conditions. Nitrogen losses via denitrification occurs when soil conditions are warm and soils are saturated with water. Thus, most potential for N loss will be later this spring.
Extension Soil Scientist
[In This Issue]
[In This Issue]
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