CMEG Crop Management Extension Group

Field Crop News

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

May 22, 2007    Vol. 07:12

IN THIS ISSUE:

Weather Outlook — Paul Knight, Pennsylvania State Climatologist

The month will conclude with a stretch of rather warm and becoming a bit humid conditions. Rainfall will continue to average below normal with the southeast third of the state (mainly from the Susquehanna Valley to the Delaware River) staying the driest.

There are surprisingly clear indications of a cool snap for a few days during the first week of June. Overall, the pattern of a very warm summer is more likely, though the dryness should ease — though it may take until July for widespread above average rainfall.

Week One (May 23–29): Increasingly warm afternoons and milder nights will be the rule until Friday. A weakening cool front should produce scattered thunderstorms in the west and northern sections later Friday. Don’t expect much cooling during the weekend as warm, humid air stays nearby. A fresh push of cooler air will trigger more widespread thundershowers later Sunday or Monday (southeast) and this will be followed by more seasonal and dry conditions early next week.

Week Two (May 30–June 5): Very warm air will quickly return by the middle of next week with only a few showers marking its return. The warmth should last until the weekend when several pushes of cooler air will arrive with widespread showers and thunderstorms. A period (2–3 days) of rather cool weather is expected from June 3–6.

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

Pokeweed Management — Bill Curran, PSU Weed Specialist

(The following article was adapted from an article written by Glenn Nice, Bill Johnson, and Tom Bauman at Purdue University).

While traveling the state this past week, I noticed that pokeweed is starting to gain some size in many of our corn fields, especially in the southeastern part of the state. Here are a few reminders about this prevalent problematic weed.

Pokeweed is a simple perennial, meaning that it emerges from the same taproot each spring. If you have ever tried to pull or dig up individual plants, you will appreciate the size of the root system that these plants are building. However, since it’s a simple perennial, it only spreads by seed production, so it’s important to target the plants prior to successful reproduction. The seeds can persist up to 40 years in the soil and can be dispersed by birds (robins, starlings, others) potentially spreading new infestations wherever these birds fly and/or roost. Many of the healthy plants we see now are new growth from roots that persist from year to year.

Control of this weed is fairly difficult with single postemergence herbicide treatments and multiple tactics are often necessary. Regardless of the crop or herbicide treatment, make sure the spray boom height is up above the pokeweed and use spray tips and a carrier volume (i.e. > 10 GPA) to maximize coverage.

Control of pokeweed in emerged corn.
Field studies by researchers at Southern Illinois University (SIU) reported common pokeweed control in corn was 90% or better with Lightning, dicamba (Banvel, Clarity, Sterling), Celebrity Plus, or Callisto (3 oz/A). Other effective treatments for non—transgenic corn include Northstar, Yukon, Distinct (4 to 6 oz/A) or Status (5 oz/A), and dicamba + Spirit. Apply when plants are less than 12 inches tall if possible. In Roundup Ready corn, use glyphosate (0.75 lb ae/A) when plants are at least 8 inches tall and make a second application if necessary.

Control of pokeweed in emerged soybeans
In the same SIU report, glyphosate controlled pokeweed 88% or higher. Control was increased when glyphosate was tank mixed with FirstRate or Synchrony STS in soybean. FirstRate and Synchrony STS alone provided 68 and 38% control. In contrast, I observed some positive results last year in a PA soybean field sprayed with Synchrony STS, so other factors (application timing, boom height, etc.) may also play a role in successful control. In Roundup Ready soybeans use at least 0.75 lb ae/A applied when pokeweed plants are at least 8 inches tall. Make a second application if necessary. In soybeans that are not Roundup Ready, use Synchrony STS (0.5 oz/A) or Classic + Harmony GT tank mixes. FirstRate may also be a potential choice, but additional evaluation results are necessary to better understand its potential for pokeweed control.

Control of pokeweed in pastures and non—cropland.
Pokeweed in pastures or in non—crop areas can also be a problem. Pokeweed can be toxic to cattle, sheep, turkeys, swine, horses, and humans. In the SIU study mentioned above, glyphosate at 0.75 to 1 lb ae/A was used on 6, 12, 24, and 48 inch tall pokeweed. All treatments provided above 95% control, but obviously the glyphosate would kill most other species including desirable grass forages. For grass pastures, Crossbow is probably the most effective herbicide and can provide the equivalent of 80% control with a 1.5% v/v mixture or 4 qt/A.

Economics of Expensive Corn and Nitrogen — Jeffrey Graybill, Lancaster County Educator

Corn is more responsive to Nitrogen (N) than any other nutrient. Top yields and high quality will not be attained without adequate amounts of this nutrient. Yet, N prices have risen significantly and are currently around $.50 per pound. As the value of a crop rises, attaining the maximum yield has increased benefits. However, as the cost of production rises, reducing your variable (fertilizer) costs provides increased efficiency and increased income. SO, the question before us is: Should I adjust my N rates in light of high value corn?

The maximum return on your investment of N is where the cost of the last pound of N stimulates a yield increase of the same value. Beyond this point, additional N does not pay for the smaller and smaller increases in yield; its called the economic optimum point.

A quick and easy way to evaluate this is to look at the ratio of the price of corn to the price of N. Historically, this has been about 10:1. For example: $2.50 corn / $.25 N. If this ratio goes significantly above 10:1 it would pay to add 10–15% more N. Consequently, if it drops much below 10:1 you should consider applying 10–15% less than normal.

Where are we today? $4.00 corn / $.50 N gives a ratio of 8:1. This is slightly below 10:1 and indicates that adding additional N, over and above the standard rates (accounting for all N sources: manure, legume and fertilizer) will not put additional cash in your pocket. Let’s efficiently manage that high priced N.

Tools such as sidedressing N and using a leaf meter or PSNT to check the N status of a field will make us efficient both economically and environmentally.

Direct—cut Barley — Paul Craig, Dauphin County Educator

What is direct cut barley? It is barley that is harvested with a small grain head mounted on a forage chopper and then ensiled. Cutting height is about 6 inches and there is no wilting of the crop. Harvest is at the proper moisture level for different silo types. Farmers with trenches shoot for 65 to 70%, upright silos at 63 – 68% and sealed silos at 55 – 60%. This is usually around the soft dough stage, when milky kernels can be easily crushed in your finger tips. Moisture monitoring and determination is critical. Yields range from 3 to 4 tons/acre of dry matter.

Unlike rye which rapidly increases its level of indigestible fiber, lignin, after heading, wheat, oats and barley actually produce more energy and protein per acre after the crop is headed. In studies at Kansas and Mississippi State, barley was rated the best choice due to higher grain yields and good fiber digestibility. In general, barley silage quality is good, with energy levels slightly lower than corn silage (TDN 64% vs. 69% for corn silage) and a protein level slightly higher (9 – 11% vs. 8% for corn silage). Stage of maturity, variety, fertility, and harvest management can greatly affect forage quality. Everyone recommends using forage testing to ensure its proper substitution in a ration.

Small grains mature much faster than corn silage. The proper harvest window will be very narrow, at most 3 to 6 days, depending on weather. This requires close monitoring of the crop, coordination with harvesters and large capacity equipment. Due to hollow stems a shorter cut, often 3/8 inch, is recommended. However, to optimize fiber in the silage do not over chop. Good packing, rapid fill and preventing air exchange are especially important this time of year, due to warmer summer temperatures.

Producers with larger acreage may choose to start harvesting earlier but too wet silage looses plant nutrients and produces undesirable, unpalatable, high butyric acid silage. Like corn silage raising the cutting height will result in a drier silage crop. Too dry conditions cause poor oxygen elimination and results in a poorly fermented product. Some have suggested mixing higher moisture alfalfa haylage with too dry barley silage. Either way, monitoring moisture is critical.

Harvesting barley as silage also provides an opportunity for earlier double cropping. This usually leads to higher corn silage yields. Using a computer simulation, Dr. Greg Roth at Penn State found that planting corn silage following barley silage harvest would yield 83% compared to full season corn silage. Waiting until grain harvest, yields were only 65%.

Evaluate Your Risk for Scab Infection — Mena Hautau, Berks County Educator

Scab or Fusarium head blight is caused by a fungus that attacks the grain directly and can result in serious yield losses. Losses may also be compounded by mycotoxins that are produced by the fungus in diseased grain. Symptoms of disease include tan or brown colored lesions that may include single spikelets or large sections of the wheat head.

Growers can assess the risk of infection by checking the site, especially if weather conditions are favorable for development.

Go to:
http://www.wheatscab.psu.edu/index.html
Click on the Risk Map Tool, then click on Pennsylvania and local county.

Adjuvants and Common Post Herbicide Tank Mixtures — Dwight Lingenfelter, PSU Weed Science

Be it weather or conflicting activities, some producers finding themselves missing the opportunity for pre—emergent weed control in field corn and are re—strategizing with post programs. The use of adjuvants with post herbicides is a critical component for effective weed control. Almost all foliar—applied herbicide labels recommend which kind of adjuvant to include in the tank when a particular product is applied alone. However, when herbicides are tank mixed, the choice of adjuvants (i.e., crop oil concentrate (COC), methylated or modified seed oil (MSO), nonionic surfactant (NIS), or ammonium nitrogen fertilizer (NH4), which includes ammonium sulfate (AMS) or liquid nitrogen (UAN)) is more difficult and sometimes not directly stated on herbicide labels, or worse yet, they conflict with each other. Below is a list of some typical post herbicides and the directions as stated on their labels regarding adjuvants and tank mixtures.

Callisto is used at 3 fl oz/acre but some labels suggest a reduced rate of 1 to 2 oz. Callisto can be tank mixed with Steadfast (ATZ), Stout, Atrazine, Option and others. If used alone or in most combinations, add COC (not MSO) plus NH4.

Celebrity Plus is used at 4.7 oz and can be mixed with Steadfast, Atrazine, or Distinct/Status. NIS and NH4 must be included whether applied alone or in a mixture.

Distinct is applied at 4 oz, but some labels suggest rates as low as 1 oz when tank mixed with other post herbicides. For best results use NIS plus NH4 under most conditions. MSO may be used instead of NIS when tank mixing Distinct with Option or Equip. Status can be used in place of Distinct at a rate of 2.5 to 5 oz/A.

Equip should be applied at 1.5 oz/acre and must include MSO and NH4 if used alone or in combination with atrazine, dicamba (e.g., Banvel, Clarity), or Distinct/Status. NIS and COC are not recommended for use with Equip or unacceptable weed control will result.

Impact can be applied at 0.5 to 0.75 fl oz/acre plus MSO or COC and UAN or AMS. Impact can be tank—mixed with various herbicides.

Lumax at 2.5 qt/acre can be applied early post and tank mixed with Accent, Basis, Steadfast, Steadfast ATZ, Stout, and Option. NIS is the recommended adjuvant. COC, MSO, and NH4 are not recommended and may cause injury to emerged corn.

NorthStar can be applied alone or in a tank mix at 5 oz/acre. NIS or COC/MSO must be included in the spray mixture, but the addition of NH4 is optional. Atrazine, Accent, dicamba or Marksman are common tank mix partners. Callisto is not listed as a tank mix partner.

Option is applied at 1.5 to 1.75 oz/acre and MSO and NH4 should be included whether it is used alone or in combination with atrazine, Banvel, Clarity, Distinct/Status, or Callisto. NIS and COC are not recommended for use with Option or unacceptable weed control will result.

Steadfast ATZ is used at 14 oz/acre and can be tank mixed with atrazine, dicamba, Marksman, Distinct/Status, Callisto, and Hornet. COC plus NH4 are the recommended adjuvants, however, NIS or MSO can be substituted. It does state that MSO should not be used with Callisto tank mixes. Also, NIS is permitted in place of COC in tank mixes that include dicamba (including Distinct), however overall weed control may be reduced.

Yukon is used at 4 oz/acre and should include COC or NIS plus NH4 if applied alone or in tank mixture with Accent or Beacon. However, use only COC if combined with atrazine.

For additional information on postemergence herbicides and their restrictions, please refer to the Penn State Agronomy Guide at http://agguide.agronomy.psu.edu/

Planter Penetration Problems — Sjoerd Duiker, Soil Management Specialist

As soils conditions become drier some reports of poor planter penetration in no-till soils have come in. The problem are due to hard soil. One has to ask what causes a soil to become hard or soft. Water content is of course a logical first, but soil tilth is an important second. Although we typically think of mother nature governing water content, there are things a producer can do to keep moisture content high in the absence of rain. One important factor is to have no living vegetation in the field: this means cover crops need to be terminated, and weeds need to be history. Another important factor is to have mulch cover. Here is where many farmers are negligent. Mulch cover is often too low for optimal no-till production in Pennsylvania. After low-residue producing crops such as corn silage or soybeans farmers should have a cover crop planted to provide the mulch cover for next year.

What about soil tilth? A farmer can improve soil tilth by increasing soil organic matter content, adding manure, by having living roots growing in the soil as many days of the year as possible, and by favoring activity of microbes and small soil animals such as earthworms. The best way to achieve this is to use continuous no—tillage systems which include cover cropping during times when the soil would otherwise be fallow. This is another area where much improvement can be achieved: many farmers do not use no—tillage continuously, but periodically plow the fields with moldboard, chisel, or disk plows. The result is that the surface organic matter content and tilth never get up to par — hence planter penetration problems.

In a long—term tillage trial at the Penn State Agronomy Farm in Centre County aggregate stability — a measure of soil tilth — in the top 2" of the soil was 81% in long—term (25+ yrs) no—till, 65% in short term (ca 5 yrs), 50% in chisel/disked, and 40% in moldboard plowed soil.

On the equipment end there are also some things that can be done to get soil penetration. Having sufficient weight on the planter is very critical. In dry soil conditions you need about 500 lbs per row. This means that a 6–row corn planter needs to weigh at least 3,000 lbs. Adequate down—pressure springs are critical, especially if you have unit—mounted coulters. You can add at least 250 lbs needed for each extra coulter. This can become an issue when using the Rawson Zone—Till system. With two extra coulters per row you need also 500 lbs of extra weight, or basically double the weight of the planter. If you have insufficient weight on the planter, it is possible to lift the whole planter up to the point where the wheel that drives the metering system doesn’t have soil contact. A more common result is, however, that the seed gets planted ½ or 1 inch deep instead of 1.5–2" deep. Herbicide damage can then play havoc on your stands.

Weight is of course also critical for drills. A 10–foot drill with units at 7.5" spacing has 16 units to press into the soil. The drill needs to weigh 8,000 lbs to do an adequate job, especially for soybean planting (which go in deeper than other crops). More coulters means more weight is required on drills. Here drill design can make a difference. John Deere drills do not have front coulters and have one—disk offset seed openers. These drills will go into the ground easier than other drills. Vermeer drills have no coulter, and off—set double disk openers which take a little more down—pressure to be pushed in the soil. Most other drills with coulters in front of double disk openers take more weight than these drills for adequate penetration.

Weed Management in CREP Grasslands — new publication available — Bill Curran, PSU Weed Specialist

A new Agronomy Fact sheet is now available in hardcopy and electronically. Agronomy Facts 66 — Weed Management in CREP Grasslands (UC198) authored by Dwight Lingenfelter and William Curran discusses weed management options for the Conservation Reserve Enhancement Program (CREP) grassland acres (CP1, CP2, and CP10). The publication discusses cultural, mechanical, and chemical control options for important problem weeds before and after crop establishment. The electronic document is available at http://pubs.cas.psu.edu/FreePubs/pdfs/uc198.pdf or for hardcopies contact:

Publications Distribution Center
The Pennsylvania State University
112 Agricultural Administration Building
University Park, PA 16802–2602

Telephone: 814-865–6713
FAX: 814–863–5560
Email: AgPubsDist@psu.edu

Upcoming Events:

Cover Crop Research and Management Summit
June 5, 2007
Tuesday, 9:30am–3:30pm
Penn State Rock Springs Agronomy Farm, Centre Co.
Cost: $10
Lunch and handouts will be provided.

During this cover crop management field day, you will have an opportunity to see and hear about the latest cover crop research at Penn State as well as observe first hand some of the tools and practices being tested. Topics will include choosing cover crops based on farming goals, how to grow or capture nutrients and the importance of carbon and nitrogen, improving soil quality, controlling cover crops including using rollers/crimpers and how cover crops can help control weeds.

This tour will be given by a distinguished group of Penn State researchers from across the college who have cutting edge projects underway focused on cover crops. In addition, Rodale Institute staff will be on hand to share their management experience in organic farming systems. Certified Crop Advisor CEU’s will be available at this event.

You must pre register with Lisa Crytser at Penn State to ensure you have a spot at lunch and on the wagons. Please pre—register by May 30, 2007 by phone (814-865-2543) or email (lac8@psu.edu).

Small Grains Field Day
June 20, 2007
Wednesday, 9:30–2:00
Penn State Rock Springs Agronomy Farm, Centre Co.
Cost: $10
Lunch and handouts will be provided.

This field day will showcase our winter wheat and winter barley variety trials, weed control issues and no—till small grain management efforts on the research farm. We will also be addressing crop insurance issues related to quality in small grains and will be reviewing some of the work with winter and spring canola on the farm this year. Certified Crop Advisor CEU’s will be available at this event.

You must pre register with Lisa Crytser at Penn State to ensure you have a spot at lunch and on the wagons. Please pre—register by phone (814–865–2543) or download a brochure at http://smallgrains.psu.edu/ Credit card registrations will be accepted.

American Forage and Grassland Conference
June 24–26 — in State College
For more information check out http://www.afgc.org/mc/page.do?sitePageId=42837&orgId=afgc

Combined Agronomy Industry / Manure, Crops, Pests & No—till Field Day
Penn State Landisville Research Farm
Friday July 6th, 9:00 AM–3:30 PM
Topics will include: Weed Management in No—till; Composting: Mortality and Nutrient Recycling; Nutrient Balance Sheet and Act 38; Farm Bill and Bio—Fuels Updates;
Herbicide Trials and Chemical Industry Updates; and Cover Crop Management. Featured equipment: No—till equipment of all types: Planters, Drills, Residue Managers.
Manure handling and spreading equipment with demonstrations (water only.)
Registrations: Lancaster Extension, 717–394–6851 $3.00 in advance, $5.00 at the door
Questions? Jeff Graybill 717–394–6851. Landisville Research Farm, Dr. Dave Johnson 653-4728

Agronomic Weed Management Research Tour at Penn State
July 10, 2007
Tuesday, 9:00–12:00 noon
Penn State Rock Springs Agronomy Farm, Centre Co.
Cost: $15
Lunch and handouts will be provided.

A number of experiments will be showcased and available for viewing including many of the new corn and soybean herbicide programs plus the latest information on herbicide resistance, cover cropping and weed management research. Certified Crop Advisor CEU’s will be available at this event.

You must pre register with Lisa Crytser at Penn State to ensure you have a spot at lunch and on the wagons. Please pre—register by July 3, 2007 by phone (814-865-2543) or email (lac8@psu.edu).

2007 Penn State Agronomic Field Diagnostic Clinic — July 24 and 25
July 24 and 25
Penn State Rock Springs Agronomy Farm, Centre Co.

The dates and topics for our annual Diagnostic Clinic have been set. As in the past, the Clinic is a one—day event conducted at the Penn State Agronomy Research Farm near Rock Springs, PA. This year’s Clinic will be held on Tuesday, July 24 and then repeated on Wednesday, July 25, 2007. The topics include cover crop selection and management, no—till planter adjustments and attachments for use in cover crops, an overview of biomass crops for alternative energy use, nitrogen management issues, and pest management topics. As always, various credits will be offered.

Registration forms will be mailed and posted on our CMEG website (http://cmeg.psu.edu/) as time gets closer, so you can register and get additional information on each of the topics.

For additional information or comments about the Diagnostic Clinic contact Dwight Lingenfelter at (814) 865-2242 or by email, DwightL@psu.edu.

Ag Progress Days — August 14–16

Contributors: Dept. Crop & Soil Sciences: Marvin Hall, Sjoerd Duiker, Bill Curran, Greg Roth, Dwight Lingenfelter, Paul Knight. County Extension: Thomas Murphy (Lycoming), Paul Craig (Dauphin), Andrew Frankinfield (Montgomery), Don Fretts (Fayette), Mena Hautau (Berks), Jeffrey Graybill (Lancaster), Kevin Fry (Armstrong), John Rowehl (Cumberland), Mark Madden (Sullivan/Bradford)

Editor:Mark Madden — Sullivan County Extension

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.