September 20, 2002

Corn harvest is underway in some eastern Nebraska fields where the corn drydown is ahead of schedule. Photo by Brett Hampton

In this week's Crop Watch:

Most grain mold pathogens become associated with the kernel in the field, but they also can grow within the colonized kernel and even spread to adjacent kernels during storage. Consequently, it is imperative to dry down grain as soon as possible. Delaying harvest to let the grain dry in the field increases the risk of stalk rots and grain molds. In some cases it may be better to harvest at higher grain moisture and dry the grain rapidly. No fungicides are labeled in Nebraska for managing molds or mycotoxins of corn postharvest.

While it's always important to monitor stored grain throughout the winter, this year it may be critical to to keep an even closer eye on moisture content, especially in areas where mold and mycotoxin contamination have been common. It also will be important to keep the grain well aerated.

Marketing options

Grain with mold symptoms should be assayed for the presence of mycotoxins prior to use as food or feed. If mycotoxins are confirmed, producers may have several options, depending on the contamination level.

Elevators in some parts of Nebraska that buy corn for both human and animal consumption are reported to have turned away grain with mycotoxin levels above 20 ppb. While some elevators may not want to risk accidental contamination of food grade corn, the contaminated grain could still be marketed to a number of other outlets, depending on the level of contamination. These might include feedlots or elevators which only buy grain for feeding cattle.

Some grain elevators use the black light test as a preliminary indication of potential toxin contamination; however, this test is very unreliable. Many things will fluoresce under a black light, including insect parts and fungi that don't produce toxins. Consequently, many false positives can result. Only certain laboratory analyses can establish the occurrence and concentration of mycotoxins.

Health and safety

Mycotoxins can be toxic to farm animals, wildlife, or humans. Effects on animals include feed refusal, short-term illness, reproductive dysfunction, and death. Human effects include suppression of the immune system, reproductive dysfunction, cancer, and death. The ultimate effects depend on duration and concentration of exposure.

Most mycotoxins are extremely stable molecules and can withstand drying processes as well as many industrial processes. Consequently, exposure can result from not only direct consumption of contaminated grain but also from consumption of processed grain and industrial byproducts such as from industrial ethanol production.

Because molds or mycotoxins can develop in stored grain, remember to exercise caution and wear a dust mask to minimize exposure. In addition to mycotoxin concerns, exposure to the spores of the grain mold fungi can lead to acute allergic responses or chronic allergic responses. Clean trucks and bins which held contaminated grain.

Resources

CCA numbers required for credit Beginning Sept. 1 all Certified Crop Advisers are required to use their assigned CCA Certification number when signing in at continuing education courses. This requirement is being implemented by the International CCA Board to add continuity to the process and privacy for CCAs. Your CCA certification number appears on your wallet ID card and also on your original CCA certificate.

• Remember to contact your insurance provider before grazing, harvesting or destroying an insured crop. Also check with the local Farm Services Agency (FSA) office if you're enrolled in NAP (Noninsured Crop Disaster Assistance Program). Also check with the FSA office on eligibility for other drought and livestock assistance programs.

• Cattle feedlot manure can contain about $6 per ton of fertilizer nutrients. The nutrient value of swine pit slurry is about $7 per 1,000 gallons. Calibrate your applicator, test your manure, and calculate crop nutrient needs to get maximum value from it.

• Manure testing is necessary to determine the correct application rate. See the "Manure Testing: What to Request", NF02-507, for analysis guidelines and a submission form for the lab. Your NRD may have a cost-share program on manure tests.

• Check your grain sorghum maturity now. With the drought this year, some grain sorghum fields matured early and producers may be surprised by how dry it is already.

  Paul Jasa, Extension engineer, said, "We harvested all of our grain sorghum at the Rogers Memorial Farm (10 miles east of Lincoln) during the first week of September at a moisture content of 14%. Due to the mid August rains, there were some newly emerged green heads in a few places. These heads hadn't pollinated yet and ran through the combine like leaf material. Those in the field now are pollinating and may be in the milk or soft dough stages later when normal harvest time rolls around."

  If producers wait to harvest in a month, these immature heads may create problems with threshing or grain quality. Also, grain sorghum maturity tends to slow down when night temperatures dip below 60^oF and there may not be enough heat units left to finish the crop this year.

This assessment from northern Holt County is based on the profitability of nitrogen applied relative to yields produced at an average price for corn of $2.31 a bushel over the last decade, according to Charles Shapiro, Extension soils specialist at the Northeast REC and report co-writer. The report, "Agricultural Management Practices and the Groundwater System of Northern Holt County, Nebraska," focuses on the Holt County Groundwater Education Project. This inter-agency effort began in 1994 to alert area farmers about the movement of nitrates from fertilizer applications into groundwater, primarily through irrigation.

The project included demonstration plots with high groundwater-nitrate levels to show the value of following NU's best management practices for nitrogen application. The project found that groundwater nitrates that are pumped and applied to corn via irrigation are as effective as nitrates applied through fertilization. Recognizing this can save farmers' fertilizer bills and help clean up contamination.

Other project leaders were Susan Olafsen Lackey, associate geoscientist with UNL's Conservation and Survey Division and senior author of the report, and William Kranz, irrigation specialist at the Northeast Research and Extension Center.

The publication recaps recommended best management practices for nitrogen applied to corn and for irrigation water application. It is available free from the Conservation and Survey Division, 113 Nebraska Hall, University of Nebraska-Lincoln; by phone: (402)472-7523; or e-mail csdsales@unl.edu. It is also distributed free from NU Cooperative Extension Publications, Box 830918, University of Nebraska, Lincoln, NE 68583-0918; or by calling (402)472-9713.

Orders can be placed at local extension offices.

Fall grazing of alfalfa, however, is not without problems. To protect your livestock from bloat, feed them hay before turning them onto alfalfa and provide access to dry hay or cornstalks. Bloat protectants like poloxalene can be fed as blocks or mixed with grain. They work well when animals eat a uniform diet each day, but they can be costly.

With fall grazing, only graze when fields are dry and firm. Reserve a small area for feeding when soils are wet to avoid damaging the entire field.

More information If you're searching for feeding options for your cattle, visit the CropWatch AgNews Web site for information from Bruce Anderson on grazing cornstalks, with and without corn.

Crop residues from corn grain production are abundant in Nebraska. Over 10 million tons will be available after harvest. That's enough to feed all the beef cows in Nebraska through the entire winter two times! These residues can provide valuable forage for beef cattle this winter to replace forage lost due to the recent drought. They also can stretch the supply of higher quality hay such as alfalfa. Unfortunately, most cattle and corn stalks are not very close to each other. One way to overcome this separation is to harvest this residue and haul it to the cows. There are many ways to harvest stalks, such as chopping into a stack wagon or cutting, raking, and baling. These methods, though, remove most of the stalk residue, which is valuable for erosion control and useful in adding organic matter back to the soil.

A better method might be to start by removing the chopper from behind the combine. Let all the husks, leaves, escaped grain, and other tailings fall directly behind the combine. Then round bale, square bale, or stack this strip of residue but leave everything else. By gathering most of the best plant parts from four, six, or eight rows and concentrating them in just two rows, a high quality winter feed is produced while soil remains protected.

These bales should have 50%- 60% total digestible nutrients (TDN). Protein might be only 5%, but with just a little protein supplement, cows could actually get fat eating these residues. Fields with heavy grasshopper or hail damage may have less feed value than undamaged crops due to less leaf material. Irrigated ground might readily produce one to two tons per acre.

Setting a value for this feed might be difficult, but if it were sold for $50-$60 per ton, corn growers would make a little money and still have stalks remaining in the unbaled rows to protect soil and replace organic matter. Livestock producers will get a good quality winter feed for less cost than the $80 to more than $100 per ton being asked for hay in many places. Before feeding, sample and test bales or stacks for protein, energy (TDN), and nitrate levels to formulate least cost rations that will be safe to feed.

Windbreaks can reduce erosion while increasing crop yields. Photo by Brett Hampton

So how does this relate to field windbreaks? Field windbreaks are widely recognized as one of the best ways to control wind erosion. Once established, they provide a barrier to wind flow resulting in a reduction of wind speed and long-term protection for soil. But field windbreaks do so much more. Research at the University of Nebraska's Agricultural Research and Development Center located near Mead has repeatedly demonstrated crop yield benefits of field windbreaks. Yields for winter wheat have averaged a 15% increase over the last 20 years. Similar studies for corn and soybean have indicated yield increases of 12% and 15% respectively.

In 1986 a researcher from the Shelterbelt Centre in Indian Head, Saskat-chewan summarized how windbreaks affected crop yields on a world wide basis (Table 1). Without a doubt, yields are increased; the real question is do these yield increases result in economic gains to producers. And more importantly, how can a Nebraska Producer take advantage of these windbreak benefits? Over the past 10 years we have developed a Windows based computer model, WBECON, to estimate economic returns from investing in a field windbreak. The model is flexible, allowing the producer to enter details based on his/her operating conditions and expenses as well as the individual's view of future commodity prices. For a windbreak system to be profitable, the financial return from the long-term average yield increase from the protected areas of the field must be large enough to compensate: for the land occupied by the windbreak, for the crop losses associated with tree competition, and for the costs associated with planting and maintaining the windbreak.

Table 1. Average crop yield increases in fields protected by field windbreaks. Crop Yield Increase (%) Spring Wheat 6 to 10 Winter Wheat 20 to 25 Barley (grain) 23 to 25 Oats 5 to 7 Rye 18 to 20 Millet 40 to 45 Corn 10 to 15 Soybean 12 to 17 Source: Kort, J. 1988. Benefits of windbreaks to field and forage crops. Agricultural Ecosystems Environment 22/23:165-190.

Using a local example, if a corn/soybean farmer from Nebraska with a 160-acre field established four single-row, parallel field windbreaks equally spaced across the field, the cost of establishment and the costs associated with land planted to the windbreak would be recovered in 10 years. By year 15, the net return on the windbreak investment would be several thousand dollars. By year 30, the return on the original windbreak investment would be over $30,000. The windbreaks would be expected to live an additional 20 years or more, providing additional income to the producer.

These returns are based on the reduced production costs and the increased yield from sheltered acres. In many cases, cost share programs and other conservation programs are available to help offset the establishment costs and may provide annual payments for acres planted to windbreaks (see below). These programs would further enhance the economic benefits from the windbreak investment.

Windbreaks also provide valuable wildlife habitat for various game and non-game species. Research also indicates that many of these plantings provide valuable habitat for insect predators, helping keep pest populations in check and reducing the need for pesticide applications. Finally, UNL field trials are testing the concept of "productive conservation" -- producing commercially valuable products from woody plants included in conservation plantings. Production of one class of product, woody decorative florals, is particularly adapted to field windbreak plantings. The accompanying article describes in more detail the potential economic returns from these plantings. For more information, interested readers may request a copy of the new publication series on agroforestry practices.

The Conservation Reserve Program (CRP), administered by the Farm Service Agency (FSA), provides 50% cost-share assistance for establishing field windbreaks and an annual rental payment for the cropland that is taken out of production and planted to field windbreaks. The CRP annual payment is for 10 years and is based upon the rental rates for the land enrolled. For a field to qualify for CRP it must be determined to be "highly erodible land" (HEL). The USDA Natural Resources Conservation Service (NRCS) helps landowners determine land eligibility and designs field windbreaks. Landowners can enroll their land in CRP only during specified enrollment periods. The enrollment process is competitively based on environmental benefits of the conservation practices that each landowner offers to establish on the field to be enrolled.

A variation of the CRP - the Continuous Conservation Reserve Program (CCRP) - differs from CRP in several important ways. Whereas CRP is intended to take entire fields out of crop production, the CCRP encourages landowners to install certain conservation practices on small land areas to provide significant environmental benefits. The eligible practices under CCRP include field windbreaks, shelterbelts, living snow fences, riparian buffers, shallow water areas for wildlife, salt tolerant vegetation, contour grass strips, grass waterways and filter strips.

Another difference with CCRP is that there is no specified enrollment period and landowners can enroll at any time. CCRP provides 50% cost-share for field windbreak establishment, along with a practice incentive payment of 40% of the cost of establishment. An additional sign-up incentive payment of $10 per acre per year is provided with the entire amount paid at the beginning of the contract period. Also, a 20% incentive is added to the annual soil rental rate for field windbreaks, grass waterways, filter strips and riparian buffers. The contract period can range from 10 to 15 years. A maintenance payment of $5 to $7 per acre is also available for field windbreaks. The local FSA staff determines eligible land, and the NRCS helps the landowner with the field windbreak design.

A third USDA program may provide cost-share assistance is the Environmental Quality Incentives Program (EQIP), administered by NRCS. This program provides support for conservation plans that include structural, vegetative and land management practices on eligible land. Cost-share payments up to 75% are available to implement one or more eligible structural or vegetative practices, including windbreaks.

A new program beginning in fiscal year 2003 is the Forest Land Enhancement Program (FLEP). This program will be administered by the Nebraska Forest Service (NFS) and provides up to 75% cost-share for a number of practices, including field windbreaks.

In Nebraska, many local Natural Resources Districts (NRD) also provide cost-share assistance for establishing field windbreaks. The NRDs administer state funded cost-share assistance for many conservation practices. The cost-share rate varies, but is commonly 50%. NRDs coordinate very closely with the NRCS and Nebraska Forest Service to provide help with designing field windbreaks and determining appropriate cost-share programs for each landowner.

Rich Straight
National Agroforestry Center

West Nile virus is a mosquito-borne virus that can cause encephalitis (inflammation of the brain) or meningitis (inflammation of the lining of the brain and spinal cord). First introduced in the United States in 1999, it has spread rapidly and has now been found from coast to coast. Wayne Kramer, state medical entomologist with the Nebraska Health and Human Services System, said as of Wednesday, the West Nile virus has been identified in 27 humans (two of whom died), 318 birds, and 825 horses.

People who work outdoors and use DEET regularly should be aware of the possibility of a reaction if DEET products are overused. Apply DEET lightly and treat clothing rather than skin.

While most of your backyard mosquitoes are probably nuisance mosquitoes of the Aedes genus, some may be of the Culex genus which can carry and transmit the West Nile virus from now until frost.

While this virus continues to be a threat, take the following steps to avoid problems:

1. Drain any standing water on your property;
2. Use mosquito "dunks" (Bacillus thuringiensis "donuts") in backyard ponds and birdbaths;
3. Stay inside during the evening when possible;
4. If you need to be outside during evening, nighttime and dawn hours when mosquitoes are most likely to bite, wear protective clothing such as long pants, long-sleeved shirts, and socks. During these periods, consider using an insect repellent containing 10% or less DEET (N, N-diethyl-methyl-meta-toluamide) for children and 30% DEET for adults. Federal and state agencies provide the following cautions for using products with DEET:
5. Do not use it on infants or pregnant women and do not allow young children to apply it themselves. Apply to your hands and put it on the child.
6. Use sparingly to cover exposed skin and clothing and don't apply under clothing.
7. DEET is effective for approximately four hours. Avoid prolonged or excessive use and do not reapply or saturate skin.
8. Wash all treated skin and clothing after returning indoors.

How does DEET work?

The material apparently works by interfering with mosquitoes' ability to detect convection currents caused by a warm body after they have been alerted by their carbon dioxide receptors. Hairs on the antennae are temperature and moisture sensitive. Mosquitoes apparently do not avoid people because of the odor of DEET, rather it is thought that DEET molecules somehow interfere with the entry pores of the female mosquitoes sensory receptors, thereby interfering with their ability to locate their hosts.

Hazards of DEET

Several years ago, the Environmental Protection Agency issued some precautions regarding the use of DEET repellents, due to some reported adverse effects on young children. In a consumer bulletin entitled, "Using Insect Repellents Safely," the agency stated, "While doctors have not confirmed DEET as the cause of reactions such as headache, mood changes (crying, irritability), confusion, nausea and, in severe cases, muscle spasms, convulsions or unconsciousness, EPA is concerned that a small segment of the population may be sensitive to DEET."

They indicated that overuses of DEET repellents may have resulted due to public concern over tick-related diseases, such as Lyme Disease. Also, many of the adverse reactions reported appeared to have involved accidental exposure, such as swallowing or spraying into the eye. People who work outdoors and use DEET regularly should be aware of the possibility of reaction if DEET products are overused. Remember to treat clothing rather than skin. Apply the product lightly, particularly if it is concentrated. Be especially careful with small children, anyone who has a history of sensitivity to chemicals and the elderly as these groups are more likely to have a reaction.

The EPA estimates 50-100 million people use DEET repellents each year, with 10 or fewer resulting cases of neurological intoxication reported. EPA did not suggest that people stop using DEET due to its overall benefits of insect and tick repellency. We must balance the risk against those of irritation, secondary infection of bites and the possibility of transmission of insect-borne diseases.

David Keith
Extension Entomologist

According to the National Safety Council, three types of users are found on rural public roads: producers, the driving public and those who jog or use the road for exercise. Farmers know the limits and characteristics of their equipment, but other road users do not. Farm equipment is slower, less maneuverable and larger than other vehicles. Combine this with later sunrises and earlier sunsets and collisions are likely to happen.

Reducing this likelihood is everyone's responsibility. Motorists should slow down when overtaking or meeting farm equipment. Swerving to avoid a combine header that extends into the opposite traffic lane can be disastrous at high speeds on a gravel road.

Farmers should only move equipment on public roads during daylight hours. Slow-moving vehicle signs should be clean, bright and unobstructed. Large equipment should have perimeter reflectors, reflective tape and warning lights. Mirrors should be adjusted to eliminate blind spots and a pilot vehicle should be used behind tractors and other equipment. Extremely wide equipment may require a second pilot vehicle in front with headlights and warning flashers. Never use work lights on equipment as a substitute or in addition to headlights and warning lights.

The most dangerous maneuver for farm equipment is making a left turn at an intersection or into a field drive or driveway. Speed must be reduced and large machines or those with long trailed equipment may have to move right to clear intersection or driveway obstructions. Following motorists may assume they are being given room to pass. It is vital that the machine operator use mirrors and turn signals to prevent a collision.

Rural non-farmer residents walk, jog or ride on rural roads for exercise or relaxation. Hiking and biking trails that cross public roads may not be well marked. Operators of larger tractors and combines may be concentrating on vehicular traffic and not notice pedestrians or cyclists on the shoulder and may need to pay special attention. Don't assume that they are familiar with farm equipment and will react accordingly.

Dave Morgan
Extension Safety Engineer

• Paul C Hay, Extension Educator in Gage County: Corn and milo harvest is underway in southeast Nebraska. Yields are low for this early harvest of dryland fields. Farmers should be fairly aggressive as most producers are reporting above average ear drop. Also, there is some concerns about alfatoxins, particularly in the food grade and popcorn markets. Lots of congestion forming in crop insurance field inspections and bin measurements as well as low test weight issues. Producers should be sure they understand clearly all crop insurance communications and keep all records required by their insurance company.
• Terry Gompert, Extension Educator in Knox County: Dryland corn and soybeans will be harvested soon. The corn is dropping ears because of corn problems ...so harvest could be early. I would estimate that 50% of the corn was put up as silage. We caught another inch or more of rain last weekend. It sure is green for having it be a drought year. Much of the blue grass in pastures has drought killed. Still trying to figure our what to do about it.
• Bruce Anderson, Extension Forage Specialist, writing in response to the question regarding the loss of blue grass in pastures: It could be a great opportunity to add higher yielding plants like orchardgrass or brome to the pasture next spring or to improve quality by interseeding legumes like alfalfa, birdsfoot trefoil, and clovers. Control of invading weeds, especially winter annuals like mustards, pennycress, and downy brome may be needed late this fall or very early next spring prior to planting to avoid excessive competition for new seedlings.

• G01-1441: Residential On-site Wastewater Treatment: Lagoon Design and Construction
• G02-1451: Climate Change and Winter Wheat: What Can We Expect in the Future?
• G02-1468: Residential On-site Wastewater Treatment: The Role of Soil
• NF02-545: A Guide to Soy Foods
• NF02-546: Soy Health Claims

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