CMEG Crop Management Extension Group

Field Crop News

Website Address: http://fcn.agronomy.psu.edu/

October 31, 2007    Vol. 07:33

IN THIS ISSUE:

Weather Outlook — Paul Knight, Pennsylvania State Climatologist

The anticipated change in the weather regime has begun. Gone are the days of long warm spells and instead a highly changeable pattern is in place which will yield to more frequent cold snaps as November unfolds. The rapid changes will limit the opportunities for precipitation, though at least a couple of statewide significant (>0.50") rainfalls are expected in the month ahead. The killing frost of earlier this week has ended the growing season in many sections and by mid—November, freezes should have occurred statewide. The first snow showers and squalls are on the horizon, but only the northwest and southwest mountains are expected to see flakes with this initial volley of wintry chill.

Week One (Oct 31 — Nov 6): Rather mild and breezy weather is expected on Wednesday. A cold front crossing the state on Thursday may bring some sprinkles, then cooler weather will follow with some new frost pockets in eastern Pennsylvania on Friday morning. Another push of chilly air will arrive during the weekend with scattered showers of mixed rain and snow in the northern counties — most likely on Sunday. A quick warm—up is expected early next week.

Week Two (Nov 7 — Nov 13): The chilliest weather of the autumn is expected by mid—week with breezy conditions enhancing the below seasonable conditions. Snow flurries and squalls will develop in the northwestern third of the state as the cold air moves in. Once again, it appears that the chill will moderate during the weekend and be followed by an even colder air mass at the start of the next week. Precipitation (other than near the Great Lakes) should stay below average.

Check out the predicted Growing Degree Days (base 55) for Pennsylvania for the next two weeks at: http://climate.met.psu.edu/data/regional_gdd.php

Reducing the Potential of Prussic Acid Poisoning — Marvin Hall, PSU Forage Specialistl

Sudangrass, forage sorghums and sorghum—sudangrass crosses (all in the genus Sorghum) contain a non—poisonous chemical called dhurrin. If these plants are damaged by freezing, chewing or trampling), the dhurrin is converted into prussic acid (cyanide) which is potentially very dangerous for animals eating these crops.

Factors Affecting Prussic Acid Content In Plants

Species. The vegetative portion of all sorghums contains prussic acid. Generally, however, prussic acid content in sudangrass is about 40 percent less than in most other sorghums. As a group, the sorghum—sudangrass hybrids have more prussic acid than sudangrass. Crosses have now been developed that contain extremely low quantities.

Plant Parts. In the sorghums, young leaf blades normally contain higher prussic acid levels than old leaf blades or leaf sheaths or stems. The seedheads are low in prussic acid, and the seeds contain none.

Maturity. Highest prussic acid levels are reached before the boot stage. As plants mature, the stalks make up a greater proportion of the plant, causing prussic acid content in the total forage to decrease.

Drought. Severe drought is probably the most common cause of prussic acid poisoning. Drought—stricken plants are hazardous to feed because they are mostly leaves.

Freezing. Forage is usually considered safe to pasture or feed as green chop 5–6 days after a killing frost.

Fertilizer. If high N rates are applied to soils deficient in phosphorus and potassium, prussic acid levels usually increase.

Safe Feeding of Potentially Hazardous Forages

Pasture. Sorghum that has wilted and dried 5–6 days after being killed by frost is considered safe for grazing. The risk of prussic acid poisoning can be reduced by feeding ground cereal grains to the animals before turning them out to graze. The chance of problems on pasture can be further reduced by using heavy stocking rates (4–6 head per acre) and rotational grazing to avoid cattle selectively grazing the leaves. If new shoots develop after a frost the crop should not be grazed until this new growth is 2 feet tall.

Green Chop. Green chop forage is usually safer than the same material used for pasture because it is not selectively grazed. Whereas in the case of pasture only the leaves may be eaten, with green chop material the total plant is consumed. Stems act as safety devices ‘diluting‘ the high prussic acid content of leaves.

Silage. Sorghum silage is generally safe for feeding. Although it could contain toxic levels of prussic acid while in storage, much of the poison escapes as a gas during fermentation and when being moved for feeding. However, as a precaution, do not feed new silage for at least 3 weeks after harvesting and storing.

Hay. The prussic acid content of sorghum hay decreases as much as 75 percent while curing and is rarely hazardous when fed to livestock.

Liming No—till — Doug Beegle, PSU Soil Fertility and Nutrient Management Specialist

Liming no—till is no different than liming in any other tillage program except that it is less forgiving if you don’t do it right. The key to liming in no—till is to lime on a regular basis and don’t let pH get low in the first place. If you maintain soil pH near to the optimum and don’t let it get below the 6.0–6.5 range for most crops, you can lime on the surface following a normal liming program and maintain the soil pH near the optimum without tillage.

However, if the soil pH is allowed to become very low, limestone moves very slowly down through the soil and thus it can take a very long time without mixing from tillage to neutralize the acidity even just in the plow layer. In research at Penn State on a long term no—till soil that had been left to become acid, it took 9 years to raise the pH in the plow layer (6”) from 5.1 to 6.5. There was no advantage in this research to applying limestone more frequently in no—till, it took a long time regardless.

If someone is transitioning to no—till the recommendation is that if the soil pH is very low, limestone should be applied and the soil tilled one more time to mix the lime and neutralize the acidity in the plow layer before beginning no—till. Then lime on a regular basis. If you are already in well established no—till and have neglected liming and thus have a low pH you will either have to apply limestone and live with the problem for a few years until the liming effect can move down through the soil or you may have to till to mix the limestone for more immediate reaction. If you choose to just apply the limestone on the surface, there will likely be some immediate benefit from the limestone in these low pH soils even though the full benefit may take years. This early benefit will be more likely in a well developed no—till soil with good residue management.

Acidity is constantly forming in soils in our region of the world, thus liming is an on—going management practice. For example, one of the biggest sources of acidity in ag soils is nitrogen fertilizer. Most N fertilizers create the equivalent of about 3 lb/A Calcium Carbonate Equivalent (CCE) lime requirement for each pound of N applied. For ammonium sulfate this is about 6 lb/A CCE for each pound of N applied. Thus, a 150 lb/A N application will create 450 to 900 lb/A of lime requirement per year. This is why agricultural soils in PA generally need 1–2 tons of limestone every 3 years or so. The actual amount needed will vary depending on soil properties so it is important to take a soil test to determine the actual lime requirement.

Remember that soil sampling no—till soils is different because most of the acidity, such as the N fertilizer starts at the surface. This can result in a very acid layer at the surface often called an “acid roof”. Normal plow depth soil samples can sometimes miss this acid layer. Therefore the following procedure should be followed when sampling long term no—till soils. Take a normal plow depth soil sample. If the test results call for limestone apply the recommended amount and no special sampling is required. Since the limestone will be surface applied it will automatically neutralize the acid roof first. However, if the normal soil test does not call for limestone, take a second sample from the surface inch of soil and check the pH. A simple field pH test kit can be used for this second test. If the normal test did not call for limestone but this surface pH is 6.0 or less, apply 1 ton of limestone/A.

The bottom line is never let the pH get too low in no—till. If you lime on a regular basis, usually every three years, to maintain the soil pH near to optimum and then no special management is required.

Moldy Ears of Corn — Paul H. Craig, Dauphin County Extension

Recently many calls and questions have been raised regarding the increased observation of molds on corn that remains unharvested. Producers across PA are looking for answers to questions related to identification and the potential for feeding challenges. Moldy grains are a complicated issue for grain producers and feeders and understanding these challenges requires information on mold identification and an understanding of mycotoxins risks and potentials.

Frequently moldy ears are associated with cool and wet environmental conditions during ear development and grain maturity. However other factors, more common this year, seem to have also resulted in moldy ears. One factor is when the corn plant stops growing late in the season during droughty conditions. When this happens the moisture in the cob and the grain are not removed by the natural dry down process but instead depend on air movement to dry down the ear. Under circumstances like this, the environment inside the husks provides ideal conditions for mold growth. Poor pollination can also favor mold development as poorly pollinated ears tend to remain upright on the stalk leading to exposure to mold spores and rainfall. European corn borer levels were high in many areas this summer due to the droughty conditions. Borers feed on the tips of the developing ears leading to exposure to mold spores. Last but not least, birds feeding on these caterpillars or other insects on the ear tips can cause damage leading to mold infection.

The three most common ear molds are Diplodia, Fusarium, and Gibberella. Diploidia is a whitish mold that first appears at the base of the ear. Try to associate “D” for Diploidia with “D” for Down. Eventually the whitish mold can cover the entire ear. Frequently blackish specks, actually mold fruiting bodies called picnidia can be seen on the outside of the husks. Diploidia will cause reduced feed value but this mold produces no known toxic affects.

Fusarium ear rot is noted for the fact that the disease is typically found “scattered” around the ear. It infects damaged kernals first. It is a whitish to salmon color. Fusarium is one of the most common ear rots found and can produce a toxin — fumonisin that can be a concern for feeding to horses. “Generally”, ruminants are not seriously affected by this mycotoxin.

The third ear rot is Gibberella. This is a whitish to slightly pink mold that starts its development on the tips of the ears. Interesting note is that this mold also causes head scab on wheat and stalk, seedling and root rots in corn. The spores of this disease can enter the ear through the silks during pollination. Gibberella ear rots can produce several mycotoxins harmful to livestock: vomitoxin (or DON) and zearalenone. Hogs are especially sensitive to these toxins but cattle and other livestock can also be affected.

Molds can be reduced in storage by two factors, temperature and moisture. At moistures less than 13% and temperatures below 40 degrees F mold growth and further grain quality losses will cease. Combining moldy ears, as soon as possible, is preferred over picking as many moldy and damaged kernals will be removed during combining. Grain cleaning prior to drying and storage will also remove many smaller kernals.

Ears for cribbing should be stored when grain moistures fall below 20%. Air movement in many cribs can be less than ideal. Often times, equipment or newer buildings have been placed that can restrict natural air movement needed to dry down ears. The removal of any fines, husks, etc. prior to cribbing is important for air movement within the crib. As with shelled corn, moisture levels less than 13% need to be reached to stop mold growth.

Molds do not always produce mycotoxins and this fact creates management complications. Some work has discovered that molds tend to produce more mycotoxins in response to environmental stresses including cool, moist conditions and/or drought. The mycotoxin from one ear rot may not cause health problems alone but other mycotoxins found in a silage feed or cottonseed or other feed ingredient may create problems. Testing of individual feed ingredients for mycotoxins can be done but we should include a complete mycotoxin screening of the ration if you suspect problems exist. Work with your veterinarian and your nutritionist to address potential problems early.

Kochia, a New Weed to Watch — Bill Curran, PSU Weed Specialist

Kochia scoparia

You may have noticed a newer weedy plant growing along the roadside and elsewhere in some areas of the state. I have really noticed kochia (Kochia scoparia) this fall growing in a number of areas where it wasn’t present in the past. Kochia is also known as fireweed, burning bush, and summer cypress and has been grown or at least investigated as a drought—resistant forage crop on lands where other crops are difficult to grow — sounds like an excellent trait for a “problem weed”. Kochia is related to common lambsquarters and was introduced to the US around 1900 from Eurasia. This plant has historically been a “western” weed being problematic in much of the Great Plains in wheat, the Southwest, Pacific Northwest, and California. It has been moving eastward for a number of years and became a presence particularly along roadsides and rights—of—way in the Midwest in the early 1990’s. It has now officially arrived on the East coast and will likely begin causing problems for us over the next few years.

Kochia infestation along the Mt. Nittany Expressway

Kochia is an annual plant and a prolific seed producer (greater than 10,000 seeds/plant). It is one of the tumble weeds where entire plants break off at the base and the seeds are dispersed as the plants blow across the landscape. Both triazine and ALS—herbicide resistance have been identified in kochia, probably as a result of soil residual herbicide use along rights—of—ways, in wheat, and other areas. Kochia is not known as a particular weed problem in corn and soybeans, but it could become a nuisance in certain areas. At this point, if you see a few new plants along the field edge or in areas that you haven’t seen this weed before, you would be wise to remove them before they set or disperse seed as this year’s 3 or 4 plants could turn into 100’s next year.

Kochia infestation along the Mt. Nittany Expressway

Kochia infestation along Nittany Expressway, State College (photo taken on Oct. 26, 2007).

Can Alfalfa be Harvested Yet This Fall? — Marvin Hall, PSU Forage Specialist

Managing alfalfa stands in the fall is really about assessing the benefits and risks. For example, you probably wouldn’t take a harvest in the fall if you knew that a very cold and open (no snow cover) winter was waiting just ahead. The risk of loosing the alfalfa stand would be greater than the benefits of taking the harvest. The benefits and risks of fall harvesting must be assessed in each situation to determine if the benefits are greater than the risks.

Below are some questions to help make the decision about taking a fall harvest or not.

  1. Do you really need the forage? If you already have plenty of forage to make it until next spring then why risk a fall harvest.
  2. Is it a younger stand? Older alfalfa stands are more likely to winter kill or suffer winter injury following a fall harvest than younger alfalfa stands.
  3. Is the soil pH and fertility at optimum? Adequate soil pH and fertility minimizes the risk of fall harvesting.
  4. Is the field well drained? Alfalfa on well—drained soils is less likely to suffer winter injury than alfalfa on poorly—drained soils.
  5. Did any previous harvests this year have flowers before cutting? Alfalfa harvest schedules which allow alfalfa to flower once during the season, minimizes the risk of winter injury.

If you answered YES to all these questions then you are at a low risk. However, for each NO answer your risk increases significantly.

Hibernating your Field Crop Sprayer — Mark Madden, Sullivan County Extension

Diligent equipment care and good maintenance practices are key management habits for optimizing the usefulness of agricultural implements and for controlling equipment costs over time. Few things are as frustrating as working on equipment when the time could otherwise be spent putting the equipment to productive use.

Cleaning and winterizing your sprayer now that its duties are done for the year is a simple process that can have you field—ready in the short—hour days of Spring. A few easy steps to follow include:

  1. Start with a sprayer as empty as possible and choose a location away from water sources and drainage channels.
  2. Begin the process with a thorough tank cleaning using a cleaning solution suggested by the pesticide label. While circulating the cleaning solution, check for plumbing leaks and cinch up any loose connections. Flush all lines by removing end plugs and nozzles being sure to remove all residues. Clean all nozzle screens and clean, or replace if necessary, all filters. Flush the system with clean water until the cleaning solution is removed and reinstall all nozzles and screens.
  3. Pressure wash the entire outside of the sprayer using a detergent removing any residues or substance that could hasten corrosion.
  4. Use a 50:50 mix of antifreeze and water to protect the plumbing, components and pump from frost damage. A five gallon mix should be added to the tank and circulated throughout the system. You can capture this solution as it free drains from the system and reuse in later years.
  5. Drain any foam marker system. Compressed air can aid with clearing the lines to the end of the booms.
  6. Lubricate wheel bearings and all moving joints and inspect for structural integrity particularly where the tank rests on the running gear and at the boom pivots. Torque all fasteners to recommended limits and inspect tires for problems.
  7. Clean and protect electronic connections and store controllers at a suitable location. A soft brush can be used to clean the connectors and a dab of electrical grease will prevent corrosion and ensure a more reliable union next time it is used. Tether the connecting cable to the sprayer so that the plug is up off the ground.

When the job is done, park your sprayer out of the weather and wait for Spring with confidence you’re ready to rock when its time to roll.

Market Outlook — John Berry, Lehigh County Extension

Some commodity pundits suggest we could be in one of those “seller” markets we all dream of. Consider the following as possible actions:

I am watching for the following as indicators of a change in the current commodity market attitude:

PDA week of October 22 grain market summary

WESTERN PENNSYLVANIA
Grain Range Avg
Corn No. 2 3.50-3.75 3.59
Wheat No. 2 6.50-8.00 7.33
Soybeans No. 2 8.88 8.88
Ear Corn 115.00 115.00
CENTRAL PENNSYLVANIA
Grain Range Avg
Corn No. 2 3.80-4.00 3.83
Wheat No. 2 ---- ----
Soybeans No. 2 8.90-9.33 9.12
Ear Corn 95.00-119.00 110.66
LEHIGH VALLEY AREA
Grain Range Avg
Corn No. 2 3.90-4.02 3.96
Wheat No. 2 7.50-7.83 7.66
Soybeans No. 2 8.85-9.00 8.92
Ear Corn 115.00 115.00

Grain In Storage?

At today’s price spreads (the difference between today’s bid and a bid some time into the future) — most markets are asking us to consider crop storage for at least a few months. If we have storage capacity and decide to utilize it as part of our marketing strategy there are a few points to remember.

Moving a cooling front through a typical grain storage bin takes at least 150–200 hours. A normal temperature management approach for storing grain is that by mid to late November grain temperatures should be cooled down with aeration into the 40s and then by the end of the year into the low 30s and upper 20s. During this initial cool down, farmers and elevator managers should look for any type of steam or any odor coming from the grain. Both are indicators that the grain is not in as good of condition as it should be. It’s possible that there is a problem in one bin and not another; it just depends on when it was harvested and what the moisture content is. Removing some of the grain from each bin will typically take the peak and center core out where there is a high accumulation of fine materials. This also provides an opportunity to sample the grain and see if you have blue eye mold damage or other types of grain damage.

If some bins have better quality grain than other bins, we may want to adjust the marketing schedule according to that and sell, ship or use the lower quality grain that may not store as well earlier in the marketing year than grain that is in really good shape. Monitoring stored grain regularly is very important. Typically we check grain quality every two to three weeks during the colder months and then more frequently as we come into the spring and summer.

How farm price affects consumer products:

Wheat production is behind wheat consumption across the globe— this leaves carry over stocks getting tighter world wide. World wheat prices that are expected to continue rising into next year are having an impact on the strategies and costs of food makers, says a spokesperson for Dunkin Brands. As a result the US company’s Dunkin Donuts chain is considering adjusting its menu and offering new products using less wheat.

Contributors: Dept. Crop & Soils Science: Marvin Hall, Greg Roth, Bill Curran, Doug Beegle and Paul Knight, PA State Climatologist; County Agents: Kevin Fry (Armstrong), Andrew Frankenfield (Montgomery), Tom Murphy (Lycoming), Dave Messersmith (Wayne), Del Voight (Lebanon), John Rowehl (Cumberland), Paul Craig (Dauphin), Craig Williams (Tioga) and Mark Madden (Sullivan).

Editor: Mark Madden, PSCE Sullivan County

Upcoming Events

Real time pest and heat unit activity: http://psu.zedxinc.com/cgi-bin/site.cgi?location=2&user=psu#

Calendar of Events: http://www.events.psu.edu/cgi-bin/cal/webevent.cgi?cmd=opencal&cal=cal209&

Readers can subscribe electronically to this newsletter at the Field Crop News Web site.

If you have problems subscribing or wish to cancel your subscription, please contact Lisa Crytser by e-mail at lac8@psu.edu or by phone at 814-865-2543.

Information presented above and where trade names are used, they are supplied with the understanding that no discrimination is intended and no endorsement by Penn State Extension is implied.

This publication is available in alternative media upon request.

The Pennsylvania State University is committed to the policy that all persons shall have equal access to programs, facilities, admission, and employment without regard to personal characteristics not related to ability, performance, or qualifications as determined by University policy or by state or federal authorities. It is the policy of the University to maintain an academic and work environment free of discrimination, including harassment. The Pennsylvania State University prohibits discrimination and harassment against any person because of age, ancestry, color, disability or handicap, national origin, race, religious creed, sex, sexual orientation, or veteran status. Discrimination or harassment against faculty, staff, or students will not be tolerated at The Pennsylvania State University. Direct all inquiries regarding the nondiscrimination policy to the Affirmative Action Director, The Pennsylvania State University, 328 Boucke Building, University Park, PA 16802-5901, Tel 814-865-4700/V, 814-863-1150/TTY.