September 6, 2002

Soybeans started to mature and yellow in eastern Nebraska with temperatures this week in the low 90s. Photo by Brett Hampton

In this week's Crop Watch:
Assessing 2002, looking forward to 2003

Yields for dryland crops will be low, making it difficult to keep enough material flowing into the combine to effectively thresh the crop without excessive damage to kernels and beans. Combine adjustment is the key to preventing excessive damage. One possibility is to increase field operating speed. This will only be successful if corresponding adjustments are made to all header controls. Gathering chain, snapping roll, and reel speeds will have to be increased with higher field speeds. Be sure to monitor both the amount and the evenness of material flow through the header to the feeder house. Uneven flows will indicate improper adjustments and can result in increased grain damage or combine plugging. Remember to adjust stripper plate and snapping roll openings on your corn head to compensate for potentially smaller ears and stalks.

Combining drought-stressed corn and soybean fields is likely to require multiple adjustments this year to compensate for reduced grain flow. (Photo by Brett Hampton)

Another solution to the decrease in material flowing through the combine is to adjust the cylinder (or rotor) speed and concave clearance. Check your owner's manual to set the machine for expected conditions and make refinements as field conditions change. Remember that the variation in yield and grain moisture content from dry areas of the field to not-so-dry areas (were there any "wet" areas this year?) will be more pronounced this year and you will have to be on your toes when it comes to in-field adjustments.

National Farm Safety and Health Week Sept. 15-21

Each year, more than 100 children are killed and 33,000 seriously injured on farms and ranches in the United States, according to the North American Guidelines for Children's Agricultural Tasks, published in Marshfield, Wis. The group's Web site offers checklists for various ag jobs and tasks, such as helping with unloading grain or silage or planting small grains, to help parents assess whether their child can safely accomplish a given task.

It also recommends safety precautions parents can take and the level of supervision for youths of specific ages. For example, for children ages 14 and up helping unload grain, it notes that the key hazards are moving parts that can entangle arms, legs, hair and clothing or dust that can cause breathing problems. It asks such questions as:

"Is the child strong enough to start the auger motor and open the door on the gravity box without straining? Children who have to strain to operate the equipment are more likely to be injured."

"Can the child balance, turn and stretch on a two-step ladder, with a spotter? Children with poor balance are likely to fall off the ladder on the gravity box."

First be sure to store sound, clean, dry grain. It may be advisable to screen out broken grains, trash and fines to increase the quality of the final storage product. Eliminating trash also will enhance fumigation, should this procedure be required later.

Cleaning and preparing bins now can help ensure that grain insects don't dimish the value of your harvest.

Since stored grain insects can invade new grain from infested harvesting and handling equipment (combines, augers, etc.), it's essential that this equipment be well cleaned. Carefully remove all traces of old grain from combines, truck beds, grain carts, augers, and any other equipment used for harvesting, transporting, and handling grain. Even small amounts of moldy or insect-infested grain left in equipment can contaminate a bin of new grain. Then clean grain bins thoroughly, disposing of spilled, cracked and broken grain and grain flour, along with the insects feeding on such material. A simple broom and a vacuum cleaner are essential pieces of equipment in cleaning grain bins.

Around the bins, be sure to remove old equipment, junk and clutter to reduce attractiveness to insects and rodents. Make sure that the bin is insect- and rodent-proofed by plugging holes, sealing bins, caulking and making general repairs. Grain spilled near the bin attracts insects and draws mice and rats. Clean up and dispose of any spilled grain several weeks before harvest. If rats have tunneled under foundations, use baits or traps to reduce or eliminate them.

Tall weeds can harbor insects and provide cover for rodents. Mow around the bin site to remove tall grass and weeds to reduce the potential for insect and rodent infestation. If necessary, re-grade the site so that water readily drains away from bin foundations. One cannot always wait for the soil to dry before loading or unloading grain from bin sites. Make certain that travel lanes have enough rock or gravel to bear the weight of heavy trucks and grain carts.

Landscaping should be maintained well away from grain storage facilities. Leave a four-foot wide strip of bare gravel around the perimeter of storage bins. If you buy old crop grain for storage with newly harvested grain, be sure to watch for insects in the incoming grain. If infested grain is purchased for livestock feed, store it away from the new crop and feed it as soon as possible. Grain stocks may be rotated or moved and a grain protectant applied.

Stored grain insects cannot live on extremely dry grain (less than 10% moisture), however, it is impractical to reduce grain moisture much below minimum moisture levels necessary for long-term storage. Insect activity and reproduction are favored, however, by high grain moisture (14% or more), especially when condensation and molds occur, and fermentation raises temperature in the grain mass. A bin of 19% moisture corn with a starting temperature of 75^oF can lose a full market grade in about five days if the aeration system shuts down, allowing the grain to heat and deteriorate. Electrical system maintenance before harvest can prevent costly downtime. Spoilage and internal heating allow insects to remain active even in winter. By properly managing grain aeration the grain temperature can be manipulated.. Grain cooling can be particularly important in reducing insect reproduction since insects are cold-blooded and not active much below 55^oF. Condensation of moisture in the grain mass is prevented by slow cooling and gradual reduction of the gradient between the grain mass temperature and the outside (ambient) temperature.

Wiring for fans and other electrical components should be inspected for corrosion and cracked, frayed, or broken insulation. Exposed wiring should be run through waterproof, dust-tight conduit. Avoid kinking the conduit, and make sure all connections are secure.

Mice often nest in control boxes where they are protected from predators. They can strip insulation from wires for nest material and their urine sometimes causes corrosion on relays and other electrical components. If rodent damage is found, clean and repair or replace damaged wiring, relays, and other electrical equipment. Then seal over knock-outs and other openings that may permit rodent entry.

Fans, heaters and ducts should be checked for corrosion and other damage. Remove any accumulated dust and dirt that may reduce operating efficiency and be sure all connections are tight to prevent air leaks that can reduce operating efficiency.

Once empty bins have been thoroughly cleaned, a residual treatment may be applied to bin surfaces to protect incoming grain from insect infestation. Follow label instructions carefully. The following materials can be applied as residual sprays to bin surfaces: malathion EC, premium grade, chlorpyrifos-methyl (Reldan 4E), INSECTO/Diatomaceous Earth, pyrethrins, or cyfluthrin (Tempo SC Ultra). Note that pyrethrins would provide a relatively short residual and that malathion is not effective for some stored grain insects due to resistance. Methoxychlor is no longer labeled as a residual spray in stored grain facilities in Nebraska.

For bins with false floors, which are inaccessible for cleaning, Chloropicrin, a bin "clean-out" fumigant, is legal to use prior to binning the grain. Other fumigants that could be used on empty bins include magnesium phosphide and methyl bromide.

Caution! Fumigants are dangerous, restricted-use pesticides and may require gas monitoring devices and respirator protection for the applicator. It is highly recommended that fumigation be done by a commercial pesticide applicator who has been trained and certified by the Environmental Protection Agency and Nebraska Department of Agriculture in safe fumigant handling and application techniques. Refer to current labels for specific details and instructions.

Applying the Farm Bill The Oct. 4 CropWatch will feature information on the new Farm Bill and how options you choose may affect your cropping decisions. For more information, also see the NU Web site at http://farmbill.unl.edu

Before selecting a specific hybrid or variety, consider what crop mix may be best for 2003. Consider several factors, including soil water storage and availability of irrigation water, including how much and when the water might be available. Other factors to consider when selecting a crop mix include crop bases, crop revenue coverage or revenue assurance programs, expected net income from each crop, ability to control the weed mix that is present, equipment and labor availability and the limitation of these items such as how many acres of corn can be planted on a timely basis. At harvest the crop mix will influence how many bushels of corn need to be dried. If corn and soybeans are being grown on the same farm, while soybeans are being harvested, corn will be drying in the field and thus less corn will need to be dried in the bin.

Based on the current drought, the number one factor in determining your 2003 crop mix may likely be the availability of water for irrigation. This will be especially true for the crop producers whose water supply comes from storage reservoirs; however, it also will be true for the many areas in the state that depend on groundwater and had significant ground water declines in 2002. Without significant precipitation, ground water recovery may be slow.

Most reservoirs are at extremely low levels as the 2002 cropping season comes to an end. Unless we have rain and snow amounts that are way above average, water from many reservoirs will be very limited in 2003. Present levels at Conservation Active Pools are shown in the table. Water storage for the North Platte Project in the Panhandle is at a deficit of 100,000 acre feet. The deficit developed as irrigation districts in the Platte River Valley borrowed water from another irrigation district. The water borrowed must be repaid at the beginning of the 2003 irrigation season before any storage accrues to the North Platte Valley Districts.

Water levels at active conservation pools at several Nebraska reservoirs. Reservoir % Full on Date Box Butte 13.0 9/2 Calamus 48.6 9/2 Enders Dam 23.2 8/30 Harlan County Dam 52.7 9/2 Harry Strunk Lake 34.8 9/2 Hugh Butler Lake 29.5 8/30 Merritt Dam 39.0 9/2 Sherman Reservoir 38.0 9/2

If you receive water from an irrigation district, consider if the crop you plant will need water earlier or later than when water deliveries may actually occur. Planting crops that need water outside the window of availability often will lead to crop stress and yield loss. Even more critical will be the total amount of water that will be available once deliveries begin.

Pump irrigators facing limited ground water resources need to ask many of the same questions. Consider how many acres can be irrigated given well capacity, distribution system and soil intake rates. When operating with limited system capacity and facing drought in the same year, yields can and most likely will be significantly reduced. Corn yields have been reported as low as 30 bushels/acre for some irrigators who were only able to apply a limited amount of water this past year.

If severely limited water supplies are expected, producers may want to consider planting a portion of their acres to winter wheat. If the crop can be established this fall, it will provide excellent ground cover to prevent soil erosion this winter and spring. If dry conditions continue, the wheat can be left in place and taken to harvest. Hopefully, spring rains will be similar to normal years which coincide with the peak winter wheat water use period. However, if water supplies rebound, the wheat can be killed with herbicides and planted with the desired crop.

This fall higher levels than normal of nitrate-nitrogen will likely remain in the soil and be available to next year's crop. In addition to less crop uptake of nitrogen, soil nitrate-nitrogen may be more than normal due to two other factors:

1. In some cases, more organic nitrogen than normal may have mineralized due to cycles of severe drying followed by rainfall events.
2. Less nitrogen than normal was lost to leaching and denitrification in 2002. The nitrogen carryover is probably greatest for rainfed conditions, but also may be significant for irrigated conditions when crop performance was less than normal.

Where significant August and September rainfall occurs, consider sowing a winter cereal cover crop into dryland corn and soybean. This will trap nitrate-nitrogen as well as protect soil from wind and water erosion.

For corn, grain sorghum and soybean producers, three scenarios need to be considered.

1. The greatest concern with nitrogen carryover is with continuous corn or grain sorghum production. Here it is especially important to sample soil to 36 inches or deeper for nitrate-nitrogen.
2. Where soybean will follow corn or sorghum, there is less concern since normally we don't apply nitrogen to soybean. The 2003 soybean crop will take up the available nitrate-nitrogen. If there is much nitrate-nitrogen, atmospheric nitrogen fixed by soybean will be less than normal but crop performance should not be affected.
3. The third scenario is where 2003 corn or grain sorghum follows soybean. We expect that the 2002 soybean used most of the available nitrogen in the soil and that there will not be much carryover of nitrogen. This is especially true where late-season growth occurred after August rains. However, where soybean performance was poor to fair, sample soil to 36 inches.

Be prepared to apply some nitrogen in the spring in case there is leaching loss of the carryover nitrate-nitrogen. If soil water supply is still severely depleted at the time of fall fertilization, reconsider the yield potential for 2003 and adjust rates accordingly. If soil water is restored during the winter and spring, additional nitrogen can be applied in the spring or during the 2003 season.

The dry year does not have much implication for availability of other nutrients. Soil should be sampled at 0 to 8 inches approximately once every four years for organic matter, pH, phosphorus and potassium, as well as for micro-nutrients which may be of concern.

The pathogen attacks actively growing portions of the plant. Symptoms occur on all plant tissues, including leaves, tassels, ears, and less commonly on stalks. When it infects the ear, it results in massive malformation of the kernels; this is the most distinctive symptom in the field.

Many questions concerning toxicity and allergenicity have been raised about corn contaminated with the spores of this fungus. There are no reports of toxicity associated with common smut in corn and it is safe to feed livestock. In some parts of the world this fungus is collected before the white cap ruptures to release spores and is considered a delicacy to be eaten by humans. Although common smut is not a specific allergen, field workers with respiratory problems should wear masks during harvest as large clouds of spores will be dispersed over the field.

Even producers who shred their stalks should consider skipping that step this fall. Shredding or tilling stalks now will cut them loose and allow them to blow away. Standing residue, still attached, is one of the most effective ways to protect soil from the erosive forces of wind and to capture snowfall. The standing residue will greatly decrease the amount of blowing soil early next spring when wind erosion is at its peak before the planting season. Producers should consider no-tilling directly into the standing residue to continue the erosion control until crop canopy can take over. Any residue left standing is less residue that has to be cut or handled on subsequent field operations.

Tillage costs include far more than just fuel, labor, and equipment. Too often the soil will dry to the depth of tillage. An average silt loam soil can hold about 2 inches of soil moisture per foot of soil. Disking 6 inches deep or chiseling 12 inches deep and allowing the soil to dry to the depth of tillage could result in a soil moisture loss of 1 to 2 inches of water. Shallower tillage, even with a rolling stalk chopper, can still result in moisture losses of about 1/2 inch per trip. If the producer irrigates, irrigation costs are increased because more water must be applied to replace the lost moisture. In addition, tillage "plants" weed seeds, increasing competition for soil moisture.

Some say the soil needs to be tilled to "open it up to let water in". Unfortunately it dries to the depth of tillage and the initial water that is let into the soil is just replacing what was lost, not adding to the soil moisture reserve. When tillage is performed, the soil surface is broken up and pulverized, making the soil prone to crusting from raindrop impact. Thus the tillage thought to open the soil up actually creates a condition that seals the soil, resulting in more runoff. The long-term use of no-till allows soil structure to build, increasing infiltration and decreasing runoff even more.

Residue cover will also protect the soil from raindrop impact, reducing erosion and soil crusting. Reduced crusting allows more rainfall to soak in. With more soaking in, less runs off. Also, the residue slows runoff giving it more time to soak into the soil. The residue acts as a mulch reducing evaporation from the soil surface, further conserving moisture. A moist soil with residue cover next season doesn't get as hot as a bare soil, allowing better root development, especially if the drought continues.

Even without drought concerns, producers should still consider using no-till to improve timeliness and profitability. The diesel fuel requirements for the typical chisel-disk-field cultivate tillage system is about 4.08 gallons per acre including knifing in fertilizer, planting, and one row crop cultivation. By switching to a no-till system, the fuel use decreases to about 1.43 gallons per acre including knifing in fertilizer, planting, and two sprayings. There is a corresponding decrease in labor requirements and an improvement in timeliness without the tillage.

With the soil moisture losses from tillage and reduced soil structure, yields are lower and production costs are higher as tillage increases. No-till tends to be the most profitable tillage system, especially when there are soil moisture and erosion concerns.

Early season weed growth had very noticeable effects on crop growth this year. Uncontrolled winter annual weeds including henbit and various mustards used so much soil moisture before planting that when the crop was planted there was not enough soil moisture for crop seed germination. The result in some cases was inadequate crop stand. Early season control of weed growth, preferably with herbicides to conserve moisture and crop residue, will prevent this moisture loss.

Allowing weed growth to occur in soybean for several weeks before removal strikingly reduced soybean growth this year due to moisture stress. Soybean weed control in particular is commonly accomplished with Roundup and various brands of glyphosate in Roundup Ready soybean.

Because glyphosate is highly effective there has been a tendency to allow weeds to grow with the crop for several weeks before removal in order to use only one glyphoste application. In quite a few cases this extended period of weed and crop coexistence resulted in a stunted crop that apparently had not completely recovered by mid-August even though the weeds were eventually removed and the fields were weed free. The obvious solution is to remove weeds early -- in the second trifoliolate stage of soybean -- to protect the crop from weed competition.

Hot dry weather reduces the performance of most postemergence herbicides including glyphosate. To counter this effect treat early when weeds are small -- a good target would be when the weeds are two inches tall. Small weeds are more easily controlled than large weeds and there is the added benefit of avoiding the early competition described previously.

Herbicide carryover

The effects of this summer's drought may continue into next year as dry weather increases the chances of herbicide carryover damaging susceptible crops next year. Soil moisture and warm soils are required for herbicide degradation, either chemical or microbial, to proceed. Much of the non irrigated land in Nebraska was too dry to support "normal" herbicide degradation this summer. Late fall and winter precipitation will have little effect on carryover because the soil will be too cold for appreciable degradation to occur. Atrazine is the herbicide most widely used with increased potential for carryover to damage susceptible crops next year. In these high risk situations, avoid planting sensitive crops. Depending on the herbicide, a herbicide resistant crop variety may be available to counter the carryover risk.

Following are some of the winners:

Best crack in Holt or Knox County: 3.25 inches wide, 30 inches deep and 26 feet long, in the yard of James and Lynette Mlady, who submitted the entry.

Best joke in Holt County: "It's been so dry at our place that we have fish in our pond that are three years old and have never learned to swim!", submitted by Helen Bilstein of Atkinson.

Best joke in Knox County was an anonymous submission attributed to the fictional Winnetoon Times.

Drought, it could be worse if:

• Your 4-H club wins best pen of five and it's grasshoppers!
• It gets dry enough that the leafy spurge chokes out the purple loosestrife.
• You make it to the middle of August, get 4 inches of rain and then your well caves in and fills your pivot with sand, the end span collapses and the end gun is pointing to heaven.
• You realize you will pay less college tuition for both your kids than the irrigation fuel bill totals up to this year.
• You haul hay to your cows but find them in the neighbor's corn when you get there! And he's got ears on his corn and three of your cows die of shock!
• The school board starts talking about changing the school mascot to a grasshopper.

Corn crown and root decay can weaken stalks and complicate harvest. Scout fields regularly for stalk rot and decay and harvest fields with significant areas of stalk rot first.

This year most of Nebraska's corn crop experienced some degree of stress ranging from mild to severe, depending on the area of the state and whether the crop was irrigated. High temperatures and a rainfall deficit during the 2002 growing season had major direct and indirect effects on both the irrigated and rain-fed corn crops.

Direct effects included scald and scorch of the leaves, sheath, and husk tissues as well as incomplete pollination due to the inhibition of pollen production and germination or a pollen shed that was not synchronized with silk production. These conditions will result in significantly reduced yields. These same weather conditions led to indirect effects on corn growth and development by affecting the activity of herbicides and pathogens. The interaction of these issues made diagnosis of some problems very difficult.

Drought-stressed alfalfa can be severely injured if it is cut during winterization, said Bruce Anderson, an Institute of Agriculture and Natural Resources forage specialist. Alfalfa producers lucky enough to have received rain recently should be noticing their fields starting to grow again, but "check your calendars" before harvesting, he said. Alfalfa does most of its winterizing from mid-September to mid-October. Cutting during this time will interrupt winterizing and increase the risk of alfalfa dying or suffering winter injury. Alfalfa needs about six weeks of uninterrupted growth in the fall to become fully winterized. This begins about three weeks before the average date of the first frost, Anderson said.

"Most years we escape serious losses following harvest during the winterization period because alfalfa plants were very strong and healthy when winterizing began," Anderson said. "This summer will be different. The drought and heat may have tipped the scale the other way."

Many alfalfa plants are weak as they start to regrow. They may not be recovered from the drought's effects. This risk of winter injury is higher than normal. Alfalfa growers should cut their hay either earlier than normal -- just before winterizing begins -- or when winterizing is completed in mid-October, he said. Even though the hay will take longer to dry later in the season, plants should be well-recovered and yield and quality should be high, he said.

"Remember, the last cutting of alfalfa affects its winter survival and next spring's vigor," he said.

Sandi S. Alswager
IANR Newswriter

For the Schedule of Speakers, visit the Market Journal Web site.

From 10 a.m. to 3 p.m. each day, NU Cooperative Extension educators and specialists from across Nebraska will be speaking at the Market Journal stage adjacent to the University of Nebraska building on Third Street. Other specialists, many of whom regularly contribute stories to CropWatch, will be available inside the building to answer questions related to agricultural production. CropWatch information and extra copies of recent issues will be available and you'll be able to search the on-line versions of CropWatch or Market Journal.

A variety of ag-related topics will be addressed during the Market Journal presentations. "Customizing the 2002 Farm Bill to Your Operation," a panel discussion led by Roy Frederick, NU policy specialist, will highlight the schedule. Questions and comments from the audience will be encouraged.

Terry Gompert, Extension education in Knox County: The drought seems to have broken here — Center had received 6.18 inches of precipitation through Aug. 29. Pastures are growing and we may get another cutting of alfalfa. Many dryland corn fields have zero yield.

Tom Dorn, Extension Educator in Lancaster County: Corn harvest for grain has started in Lancaster county. I have heard reports of shorter season dryland corn coming out of the combine at 14.5% to 18% moisture. As expected, yields are much below average. Some fields have been assessed by crop insurance at less than 5 bushels per acre. I had a report on one field that has been combined. It yielded 22 bushels per acre. I have been in some dryland fields doing stand counts and potential yield assessments. I have found fields that have less than 10 bushels and others with 40-60 bushels per acre yield potential. Soil type, amount of tillage, weed control, compaction, salinity, grasshopper damage, all contribute to the variability.

Early season soybeans are beginning to turn color. Recent rain is helping beans to fill, but there are much fewer pods per plant than average. Grain sorghum has turned color in the areas that had enough moisture to head normally. Somewhat to my surprise, areas that had not headed previously are putting out small heads now that we have some soil moisture. These later heads are just pollinating. I wonder if there is time to mature grain on these late heads. One thing is certain, there will be a big difference in maturity, making harvest difficult.

Alfalfa is greening up. With high hay prices, the temptation is to use the forage immediately, but I would recommend not doing so. Alfalfa has suffered greatly from the drought. If you plan to keep the alfalfa stand past this fall, allow the new growth time to build energy into the root system. How we manage forage this fall will affect the life of the stand and will make a big difference in forage yield next year. This forage will not be lost. Alfalfa can be harvested after mid-October with much less effect on the long-term stand health.

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