CMEG Crop Management Extension Group

Field Crop News

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

October 3, 2007    Vol. 07:31

IN THIS ISSUE:

Scheduling Note

This month there will be two more issues of the Field Crop News (16 Oct. & 30 Oct.). In November the Field Crop News will go to one issue per month through February (13 Nov., 11 Dec., 22 Jan., & 12 Feb.). In March we’ll go back to two issues (11 March & 25 March). The Field Crop New will return to weekly issues in April.

Weather Outlook — Paul Knight, Pennsylvania State Climatologist

An exceptionally dry September was noted in the southeastern part of the state (with less than 25% of normal rain), though almost the entire state had below average rainfall last month. When compiling the top 25 driest summers in the past 112 years (which includes 2007), more than 70% of the autumns that followed were drier than normal in Pennsylvania. Since most of these past cases are related to occurrences of LaNina (the cold phase of the Pacific Southern Oscillation) in the late summer, there are several reasons to believe that the current dry trend will persist through the autumn. Be aware though, that in spite of the long dry period (which started in January), there have been and will likely be occasional wet spells (such as mid-April and early August). Odds favor another wet spell within the next six weeks.

Week One (Oct 2 - Oct 8): Very warm weather will persist through the period with no frost expected. There will be periods of cloud cover, which when occurring in the p.m. will elevate nighttime readings. Any sunny days will see readings rise toward record levels (80’s and upper 70’s). A cold front will approach northern sections during the weekend with scattered thunderstorms and there is a possibility of a back-door cool front early next week with low clouds and drizzle covering the eastern half of the state.

Week Two (Oct 9 - Oct 15): Very mild conditions are expected during the first half of this period with scattered showers. More than half of the computer guidance indicates that a push of very cool air is likely between Oct 13-17. This would be preceded by the first significant rain in several weeks. The cold snap would produce new frosts in the central and northeast counties.

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

The ABC’s of Fall Herbicide Treatments — Bill Curran, PSU Weed Specialist

Although we have some experience with fall-applied herbicide programs for corn and soybean production in Pennsylvania, our colleagues at Ohio State University have more and the practice is more widely adopted in Ohio and Indiana. The following article was written by Dr. Mark Loux at Ohio State University and does a nice job laying out the options.

Fall herbicide treatments have become a fairly common practice for some no-till producers, who recognize their value for managing certain tough winter weeds and providing a weed-free seedbed in the spring. Fall herbicide treatments should accomplish two major goals. First, the fall treatment has to control winter annual, biennial, and perennial weeds that emerge in late summer or fall or are already present at the end of the previous crop’s harvest. Weeds in this category include chickweed, annual bluegrass, purple deadnettle, marestail, wild carrot, and dandelion, among others. These weeds overwinter and regrow in the spring, interfering with crop establishment and early-season growth, and they need to be controlled by a fall or early-spring herbicide application. A secondary goal is to prevent seed production by these weeds, which reduces future weed infestations. While they may not provide complete control, fall herbicide treatments are by far the most effective method for controlling dandelion, poison hemlock, and wild carrot.

The primary value of fall herbicide treatments is control of weeds that have emerged by the time of application, which typically results in a weed-free field next spring, at least until sometime later in April. This can be accomplished with about $6 to $12 worth if herbicide. Some considerations for fall treatments:

  1. Effectiveness of the treatment is important — speed of control is not. The most effective fall treatments will result in weed-free fields the following spring, even if they do not appear to be controlling much later in the fall.
  2. There is a core group of herbicides that will control emerged weeds when applied in the fall. Combinations of two herbicides are usually more effective than any single herbicide, since every herbicide is weak on at least one or two weeds that are found in fields in the fall. Effective fall herbicide treatments include the following: 
    Any crop next spring 
Glyphosate + 2,4-D 

Soybeans next spring 
Canopy EX or DF + 2,4-D 
Glyphosate + 2,4-D 
Sencor + 2,4-D (excluding dandelions) 
Autumn + glyphosate or 2,4-D 

Corn next spring 
Basis + 2,4-D 
Glyphosate + 2,4-D 
Simazine + 2,4-D 
Autumn + glyphosate or 2,4-D
  3. Some additional comments on these treatments, based on the results of OSU research:

    - Glyphosate + 2,4-D is the most effective for control of perennials (other than dandelion) and most biennial weeds (glyphosate can be added to the other treatments to accomplish this). Control with glyphosate applied alone is often similar to the combination of glyphosate + 2,4-D, but the 2,4-D is needed for glyphosate-resistant marestail. Application of 2,4-D alone controls many winter annual weeds, but 2,4-D will not control chickweed and is less effective on dandelion applied alone versus mixtures with other herbicides.

    - Combinations of 2,4-D plus Canopy or Basis have been the most consistently effective on dandelion. The combination of Express plus 2,4-D is also effective, but does not have residual activity on later-emerging weeds.

    - Autumn has been more effective when mixed with glyphosate, rather than 2,4-D.

    - In OSU research, Canopy + 2,4-D treatments have been the most effective for fields planted to soybeans the following spring. Control of emerged weeds in the fall can be similar between Canopy EX/DF and the other treatments, but Canopy provides the most effective residual control of spring-emerging winter and summer annuals. Within the labeled rate range, any Canopy rate is usually effective for control of emerged weeds, but the increasing the rate can improve the control of summer annual weeds that emerge the following May/June.

    - Basis and simazine treatments provide limited residual control of spring-emerging weeds, and primarily early-emerging winter annuals. The choice of herbicide programs for in-season weed control in the following year’s corn should largely not be based on what was applied in the fall. In other words, a comprehensive herbicide program is needed in corn regardless of whether herbicides were applied the previous fall, with the exception that the preemergence herbicides may not need to have much burndown activity in fall-treated fields.

  4. For control of winter annual weeds, apply herbicides anytime after early October. The amount of crop residue on the soil surface has not appeared to affect herbicide activity in our research. However, there may be some benefit to waiting a week or more after harvest, where possible, to allow crop residue to settle. For the most effective dandelion control, delay application until after a frost. We have applied as late as early December for control of winter annual weeds, but we generally recommend application when dandelions are still mostly green, or by mid-November if possible.
  5. Apply glyphosate-containing treatments with ammonium sulfate, and additional nonionic surfactant if specified by the product label. We have generally used crop oil concentrate (plus 28% in some instances) in treatments that do not include glyphosate, but manufacturers may have specific adjuvant recommendations that optimize their product’s activity.
  6. We question the value of treatments that cost more than about $12, because the additional money does not result in more effective control of emerged weeds. Treatments that cost more can be the result of adding; 1) herbicides that speed up activity, but do not improve the end result (Aim, for example); or 2) herbicides with residual activity (Valor, Scepter, etc), to control spring-emerging weeds. Whether fall is a good time to apply residual herbicides is still debatable.

Video on Sampling for the Late Season Cornstalk Nitrate Test Now Available on the CMEG Web site — Douglas Beegle, Soil Fertility Specialist

The Late Season Cornstalk Nitrate Test has been demonstrated to be a reliable end-of-season indicator of crop N status. It provides a good assessment of whether the crop had the right amount of N, too much N, or whether it ran out of gas. This information combined with records of N management can be very useful for making and fine tuning future N and manure management decisions. For the test results to be valid the sampling instructions must be followed carefully. Extension educators Jeff Graybill and John Rowehl have produced a short video titled “Using the Late Season Corn Stalk Nitrate Test” which demonstrates the proper procedures for taking Late Season Cornstalk Nitrate Test samples. This video can be accessed by clicking on the title above or from the CMEG Web site. More information on this test can be found on the Penn State Agricultural Analytical Services Laboratory Web site

Corn Yield Calculation Issues — Greg Roth, PSU Grain Crop Specialist

Another corn harvest is underway. It’s a good time to review some of the fundamental questions that arise when estimating corn yields.

  1. How do I estimate the acreage harvested?

    If the area is a square or rectangle, you can measure the length and width in feet, multiply these two together, and determine square feet of the area harvested. Then divide this by 43560 to determine the acres harvested. Example: 100 feet x 650 feet = 65000 square feet = 1.49 acres

  2. What if the field is irregularly shaped?

    An alternative is to measure the row lengths, determine the average row length and then multiply the number of rows by the row length and then by the row width in feet. Then convert to acres. Example: 40 rows x 2.5 feet/row x 650 feet= 65000 square feet = 1.49 acres

  3. We have now harvested 10000 pounds of grain from our 1.49 acres. The grain moisture is 22% and the bushel weight is 54 pounds. How do I calculate the yield?

    First, calculate the dry matter of grain harvested by multiplying the dry matter (0.78 in this case) by the grain weight: 10000 x 0.78= 7800 pounds

    Then adjust the grain weight to 15.5% moisture basis by dividing by 0.845: Example: 7800/0.845 = 9230 pounds.

    Then divide by 56 to convert the pounds to bushels. The actual bushel weight of the grain is not used in the yield estimate. Example: 9230 pounds/56 = 164.8 bushels

    Then divide by the 1.49 acres to get bushels per acre: 164.8/1.49 acres= 110.6 bushels/acre.

    An alternative is to use this formula: (Field weight x (100-moisture)/(100-84.5) ) / 56 /acres= bushels per acre

  4. Ok, I want to sell this corn for high moisture corn to the local dairy farm. What is the equivalent value of the corn at 22% moisture ($/ton) if the corn at 15.5% is priced at $4.00/bushel?

    Estimate the dry (15.5%) bushels in a ton of wet corn and then convert this to dollars using $4.00/bushel. Example: 2000 lbs wet corn x (0.78/0.845) / 56= 32.96 bushels 32.96 bushels x 4.00/bushel = $131.86/ton (This represents the highest value of the corn and a starting point for negotiations. It does not account for drying, storage and other costs that can be avoided with high moisture corn harvest and sale)

  5. I took my wet corn to the mill and estimated the bushels using the method described above, but ended up getting paid for fewer bushels. What’s up with that?

    Grain buyers generally add a discount for shrinkage during handling that exceeds the loss due to water loss alone. This discount can vary among buyers so it pays to familiarize yourself with the discount schedules where you can market grain. For more information on how the additional shrink is calculated, see this factsheet.

Testing for Soil Organic Matter — Sjoerd Duiker, Soil Management Specialist

Most agronomists are keenly aware of the need to maintain optimum levels of N, P, K, Ca, Mg, S, and micronutrients in the soil. Manure, lime, and fertilizer applications are determined based on yield potential and soil testing for pH and available nutrients. Despite the fact that we are aware of its importance, we often neglect to monitor the levels of organic matter in our agricultural soils. Why would we bother? It is difficult to put a dollar-value or yield increase on increasing soil organic matter levels, but we do know that our soils will be more productive when they have higher organic matter contents. This was again confirmed in the Maryland study I reviewed in FCN 29 (Sept 19th), where soils with organic carbon contents of 1.76% to 6" depth (approx 3.5% organic matter) yielded 107 bu/A corn, instead of 92 bu/A on fields with organic carbon contents of 1.33% (2.7% organic matter) — a 15 bu/A yield increase due to 0.8% increase in organic matter. Humus itself is an important contributor to improved soil physical properties, such as soil structural stability, porosity, tilth, infiltrability, and water holding capacity. In addition, organic matter also contains nutrients that are released gradually during the growing season depending on climatic conditions. For example, the nitrogen contained in organic matter of a soil with 2% OM is about 1667 lbs/A whereas it would contain 2500 lbs/A nitrogen if the organic matter content would be 3%. Suppose 10% would be released in a season, this would be 167 lbs/A N in the first, compared with 250 lbs/A in the latter case. Synchronization of the release of nitrogen from soil organic matter is usually well synchronized with the needs of summer crops such as corn. As a start, farmers should be encouraged to determine the organic matter contents in their soils. The Penn State organic matter test costs $5 and can be requested when sending in a soil sample for fertility analysis. It would be advisable to measure organic matter every 3–5 years. More frequent testing is not justified because organic matter content changes very slowly. The next question on our mind is of course what can be done to increase soil organic matter contents, but we will keep that for the next issue of FCN.

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

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.

Market Outlook — Tom Murphy PSU Extension/Lycoming Co.

The grain markets have shown quite a bit activity the past week, mostly upward. Corn finished last week down but it still edged closer to some of the high prices seen during the peak this past June. Dec corn got to a 3.85 at the Chicago Board on Friday before settling the day at 373. Locally that is still translating into $4.00+ corn in most areas of the state with the exception of some of the western mills. December 08 corn is also in the $4.00+ range so you might want to consider some forward contracting for a portion of your next year’s crop. Beans are also trending up, which just like corn is following wheat. With the amount of wheat going to feed worldwide, very tight world wheat stocks, and the current seemingly unstoppable wheat price increase, this is making some bullish moves happen in the market place across the U.S. But we are still on the early side of harvest and indicators for corn anyway are showing the potential for higher then expected harvest yields from September. This could cause a drop in price on the Board. With a short crop expected in much of PA and rail being tight nationwide, PA prices anyway should be steady or better into the heart of the harvest season. Growers are finding corn in the high teens and beans as low as 11% in fields in PA, so the crop harvest is rapidly progressing from silage to grain.

It seems everyday brings new activity in biofuels, either in discussions and activity in the field. Ethanol production nationwide continues to increase, which will further use more crop, but the price is dropping as more of this new commodity enters a marketplace that can’t blend all it is already getting due to lack of blending facility capacity. Ethanol price is off roughly $1.00 gallon since a peak in the spring. There is also a growing debate on the effects of corn being diverted to fuel production. That discussion has been going on for years but with the surge in price, and amounts of corn now going in that direction, the debate is being played out in more public arenas. As you see the opportunity to discuss the subject with your non-farm neighbors, seize the chance to explain how little of the increase in price they pay for something is due to the commodity and how you are helping achieve a greater level of energy independence for the nation. In that same line of thinking, it is amazing to see the number of small producers of biodiesel that are showing up around the state. I find I am spending increasing amounts of time working with producers now trying to add value to oilseed commodities, some traditional —soybeans, some newer —canola, along with utilizing the byproducts such as glycerin. It’s an exciting time to be in agriculture!

Grain Market Prices for PA (as provided by PA Dept. of Agriculture 10/1/07)

Southeastern Pennsylvania
Grain Range Avg Contract for Harvest
Corn No. 2 3.93-4.20 4.08 3.78-3.93
Wheat No. 2 8.64-9.10 8.77 6.30-6.39
Barley No. 3 2.90-3.20 3.00 2.50
Oats No. 2 2.40-2.70 2.55 ---
Soybeans No. 2 9.31-9.46 9.39 9.36-9.46
*Gr. Sorghum --- --- ---
Ear Corn 108.00-120.00 115.33 ---
Western Pennsylvania
Grain Range Avg
Corn No. 2 3.84-4.10 3.69
Wheat No. 2 5.20-8.34 6.77
Barley No. 3 3.00 3.00
Oats No. 2 1.50-2.50 2.14
Soybeans No. 2 8.96 8.96
Ear Corn 105.00-115.00 110.00
South Central Pennsylvania
Grain Range Avg
Corn No. 2 3.90-4.25 4.02
Wheat No. 2 7.00-8.70 8.05
Barley No. 3 2.75-3.35 3.18
Oats No. 2 2.50-3.00 2.67
Soybeans No. 2 8.91-9.50 9.06
*Gr. Sorghum --- ---
Ear Corn 110.00 120.50
Central Pennsylvania
Grain Range Avg
Corn No. 2 3.90-4.20 4.08
Wheat No. 2 8.89 8.89
Barley No. 3 2.75-3.00 2.88
Oats No. 2 2.30-2.70 2.46
Soybeans No. 2 9.00-9.50 9.29
Ear Corn 108.00-119.00 115.00

UPCOMING EVENTS

No-Till Short Course - Part 1 (fundamentals and theory)

October 3-4 PSU Agronomy Research Farm / Rock Springs, PA

No-Till Short Course - Part 2 (management and field applications)

October 10-11 PSU Agronomy Research Farm / Landisville, PA

Register online at a href="http://www.panotill.com/shortcourse.html or call Lisa Crytser 814-865-2543 for more information.

8th Annual Pennsylvania Crop Insurance Conference

Wednesday, October 10, 2007, 8:00 a.m. to 4:00 p.m. at PA Farm Show Complex

Field Extension Educational Lab — October 11, Southeast Research and Extension Center Contact: Del Voight 717-270-4391

Keystone Crops and Soils Conference — October 23-24, Holiday Inn, Grantville

Contributors: Dept. Crop & Soil Science: Doug Beegle, Bill Curran, Sjoerd Duiker, Marvin Hall, and Greg Roth. Paul Knight, PA State Climatologist. Extension Educators: Andrew Frankenfield (Montgomery), Mena Hautau (Berks), Joel Hunter (Crawford), Mark Madden (Bradford), Lee Miller (Beaver), Tom Murphy (Lycoming), John Rowehl (Cumberland), Del Voight (Lebanon), Craig Williams (Tioga).

Editor: Joel Hunter, PSCE Crawford County

Upcoming Events

Real time pest and heat unit activity: http://agsci.psu.edu/news/spotlight/pa-pipe

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

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