CMEG Crop Management Extension Group

Field Crop News

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

March 25, 2008    Vol. 08:04

IN THIS ISSUE:

Weather Outlook — Paul Knight, Pennsylvania State Climatologist

The expectation that March would turn cooler (and stay wet) is working out, though it is late in cooling down. The period from this Thursday into Saturday will bring an assortment of inclement conditions from icy rain and snow near the NY border to a few strong thunderstorms at the Mason-Dixon Line. In between, it will be dull and wet at times with some spots receiving enough rain to bring streams out of their banks (especially in the western third of the state). No substantial change in this cooler than average pattern is foreseen into early April. Odds favor the pattern shifting about mid-month after a very cool outbreak which will be followed by a marked warm spell.

Provided the La Nina continues to play a role in the state’s weather during the spring, there should be a growing drought in the Mid-Atlantic region that may influence southern and eastern parts of the Commonwealth later in April and May, though cooler than average conditions should persist. At the same time, summer rainfall is expected to be a bit below normal with June and August favored to be on the wet side for the majority of the state.

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

Soil Compaction Threat Continues — Sjoerd Duiker, Soil Management Specialist

Spring is around the corner and manure needs to be spread before the corn goes in. The potential is there to cause serious compaction, as we already alluded to in last week's Field Crop News. This week I’d like to add a few thoughts on the issue of compaction.

  1. Creating more flexibility to spread manure by diversifying crop rotations.

    Diversity in the crop rotation is extremely helpful to manage manure. For example, sorghum, sorghum/sudangrass, or sudangrass can yield very well in Pennsylvania, and are especially suited to droughty soils. These crops can be established later than corn, offering a great opportunity to enlarge the window of manure application. In many cases, ryelage can be harvested, manure applied, and sorghum/sudangrass planted. In a presentation at the Pennsylvania Professional Crop Producers Conference earlier this month a farmer highlighted his success with this system, and the high yields and milk production per acre achieved (very competitive with corn silage). Another worthwhile consideration is to add a small grain to the rotation, opening a great opportunity to spread manure in the summer. I think we have underestimated the value of diversity in the crop rotation for manure management. For one, the storage doesn’t have to be as big. At the same time, one can have smaller manure spreading equipment, and still get the job done on a timely basis. In addition, it is easier to monitor soil moisture conditions, causing less compaction.

  2. The importance of living roots to make soil resist compaction

    If a soil is without living vegetation it is much more sensitive to compaction then when it has a good root system in it. There is research available to show this, and there is also the casual observation that we drive on sod if we want to avoid getting stuck. So having a cover crop in the field is a way to make the soil resist compaction better, and to allow for a greater opportunity to spread manure in the spring (or fall).

  3. Measuring soil compaction severity with the penetrometer.

    The soil compaction tester, or penetrometer, is used to measure soil compaction. A few tips for its use: In most cases, use the small (1/2”) tip. Check that the tip is not worn or your readings will be low. Use the appropriate reading scale for the tip (usually the inside scale for the small tip). Take 3–4 readings per acre, and record penetration resistance at each 3” interval. If you see spikes in the penetration resistance just below the depth of tillage, that is an indication of a plow pan. You have to realize that penetration resistance varies depending on moisture conditions. The guideline is to measure compaction when the soil profile is at field capacity (48 hours or so after a thoroughly soaking rain). If you measure compaction when the soil is muddy, you will get low readings. More common, if you measure compaction when the soil is dry, you get high readings. So you need to be at field capacity for the numbers to mean anything. Roots of most plant species cannot penetrate soil with a penetration resistance greater than 300 psi, and they are impaired when the resistance is between 200 and 300 psi. These results are true for a soil that has no macro-structure (pulverized soil). In a long-term no-till soil, penetration resistance may not be a helpful measure because of the development of macro-structure with many vertical and horizontal channels that roots will follow. In addition, rocky soils pose a problem for the use of the penetrometer. For more information on how to use the penetrometer and how to interpret the results, go to http://cropsoil.psu.edu/extension/facts/agfacts63.cfm.

  4. Tillage the short-term fix but not the long-term solution

    Tillage is a short-term solution to fix severely compacted soils. However, tillage is destructive and does not help to construct a high-quality soil. It is therefore much better to avoid tillage and manage your traffic and crop rotations so you can have a successful no-till system. You will find that, over time, your soil resists compaction better if you use continuous no-tillage, diverse crop rotations, and cover crops.

Weed Control in Winter Wheat — Bill Curran, PSU Weed Specialist

Populations of winter annual weeds are starting to show their colors in late March and early April and can compete with wheat and barley and slow the rate of crop development potentially reducing yield. If winter annual weeds like common chickweed, henbit, purple deadnettle, marestail, and others emerge with the small grain and are left unchecked, the potential impact on yield could be great. Harmony Extra is still probably the most broad spectrum herbicide for broadleaf control. Remember that 2008 Harmony Extra is now a 50SG, so 0.4 oz of the older 75XP = 0.6 oz of the new 50SG. Harmony GT contains only one of the active ingredients (thifensulfuron) in Harmony Extra and thus does not have the same weed control spectrum. Clarity, Banvel, 2,4-D, or MCPA can improve the control of some winter annuals and perennials and Stinger is the most effective small grain herbicide for thistles. Harmony GT or Harmony Extra should be included where control of chickweed is desired, since these are the only herbicides that control this weed. Huskie from Bayer and Rage D-Tech from FMC are two new broadleaf herbicides for wheat that you may see out on a limited basis this spring.

Herbicides applied in early spring can be slow under the typically cool conditions in March and early April. Remember that cool (less than 50 F) cloudy days can reduce herbicide activity. Applications this early are not likely to effectively control dandelions or Canada thistle. These weeds would be more effectively controlled with a later spring application.

Winter annual grasses, such as downy brome, cheat, annual bluegrass, and annual ryegrass are also becoming more of a problem in Pennsylvania. The wheat herbicides available for control of grasses, Axial, Prowl H2O, Maverick, Osprey, and Olympus, are most effective when applied in the fall. Some of these products can work in the spring, but to be effective, the weeds must be small or not yet emerged (Prowl). In addition to these, Olympus Flex and Finesse Grass and Broadleaf may also be labeled in PA and would be particularly useful for downy brome control. Both these herbicides have important recrop restrictions. Check with your local Bayer (Olympus) and Dupont (Finesse) reps about availability.

Most herbicides can be applied using 28% UAN as the spray carrier, although some labels do not provide much guidance on this. Warmer air temperatures at application (60’s+) as well as humidity will increase foliar burn. Also, cold nights immediately following application (and especially after warm days) that slow plant growth and development and also slow herbicide metabolism and cause greater injury. If using nitrogen as your carrier with Harmony Extra or Harmony GT, no need for a surfactant unless targeting wild garlic over 8 inches tall. If liquid nitrogen is diluted with water and less than 50% of the spray mix, then include a nonionic surfactant at ½ to 1 pint/100 gallons of solution. If applying Harmony products in water, use nonionic surfactant at 1 qt/100 gallons. Tank mixing Harmony Extra with Banvel or Buctril may result in reduced control of certain broadleaves. For 2,4–D, mixing with N solution varies with the formulation, so check the label. The ester formulation (2,4–D LV ester) can be mixed directly with nitrogen, but labels recommend good agitation. Amine formulation of 2,4–D (2,4–D amine) should be mixed with 3 to 5 parts of water before adding it to the nitrogen solution. Research from Ohio State University suggests that wheat should tolerate application of herbicide in 28% UAN well into April, as long as the restrictions on herbicide labels relative to wheat growth stage are followed. For products that are applied with surfactant, consult labels about the surfactant rate when applying in water vs. 28%. Surfactant rates may be reduced to minimize the risk of injury when applying in 28%. For more details about the OSU study, go to http://corn.osu.edu/index.php?setissueID=172#I.

Can early fungicide applications pay off in wheat? – Dave Johnson, Southeast Research and Extension Center, Lancaster County.

The time for applying herbicides and nitrogen fertilizer is upon us, and with the high wheat prices many farmers are interested in the possibility of applying low rates of fungicides at this early growth stage. Several foliar diseases can reduce wheat yield and quality in PA on susceptible varieties, including powdery mildew, Stagnospora leaf blotch, leaf rust, tan spot, and Fusarium head scab. Typically fungicides in wheat are applied to protect the flag leaf, and the question remains: can a fungicide applied at this early growth stage give a positive yield benefit?

Our experiences in PA are limited, but information from other states will help. In 2006 we sprayed 3 oz/a of Headline at greenup, but did not see a yield response. This was the year when we had lots of wet weather during grain dry down, causing grain sprouting in the head. At harvest we did notice a lot of sooty mold present in untreated fields, with dark coloring to the straw. In the Headline—treated fields, even those treated at the early timing, there was much less sooty mold and the straw was much cleaner.

Dr. Carl Bradley at the University of Illinois recently reported results from Dr. Bryan Young at Southern Illinois University, who sprayed Headline at 3 oz/a at Feeks stage 5 (greenup) on several wheat varieties in 2004 and 2005 (see http://www.ipm.uiuc.edu/bulletin/article.php?id=881). Headline at this early growth stage gave significant yield increases on 6 of 25 varieties in 2004 (a heavy disease pressure year), and 2 varieties in 2005 (low disease pressure). Yield increases were more consistent if application was delayed until growth stage 9 (flag leaf emergence). Their conclusion was that while you can get a positive response to fungicide application applied at the early growth stage, it will not protect the flag leaf as effectively as later applications. An advantage is that it could be applied at the same time as a herbicide.

Glyphosate Resistant Johnsongrass Identified in Arkansas and Mississippi — Bill Curran, PSU Weed Specialist

Earlier this month, the University of Arkansas, Mississippi State University, and Monsanto confirmed glyphosate resistant johnsongrass in a field in southeast Arkansas and in another field near Clarksdale, Mississippi. In the Arkansas situation, the field had been in continuous Roundup-Ready soybeans and there had been a history of control issues for the last few years. The first case of glyphosate-resistant johnsongrass was identified in northern Argentina back in 2005 and the problem continues to spread in that region. In the Arkansas and Mississippi fields, the johnsongrass is still susceptible to the post graminicides (ACCase inhibitors such as Select). Unfortunately, ACCase-resistant johnsongrass was also identified in several U.S. states including Mississippi dating back to 1991. With johnsongrass added to the list, five glyphosate-resistant weeds have now been identified in Arkansas including common and giant ragweed, horseweed, and palmer pigweed. Resistant johnsongrass is a particular concern since it is perennial and can spread by seed and rhizomes and few herbicides can selectively control the weed. In addition to glyphosate and the ACCase inhibitor herbicides, some ALS inhibitors are also active on johnsongrass. However, according to Heap 2008 (www.weedscience.org), ALS-resistant johnsongrass has been identified in both Texas and Indiana. I think the weeds are winning the war…

2007 Field Trials Research Report Available Online — Bill Curran, PSU Weed Specialist

The 2007 Field Trials Research Report is available for viewing as a pdf document at www.weeds.psu.edu/research.html#report. The report contains a summary of the herbicide evaluation trial results for corn, soybean, small grain, forage and some vegetable weed control trials that were conducted back in 2007.

Forage Seedbed Preparation — Marvin Hall, PSU Forage Specialist

For a forage seed is to have a chance of emerging and establishing, the seedbed must allow accurate seeding depth regulation and good seed-to-soil contact. Regardless of the seeding method (notill, conventional tillage or broadcast) it is very important that seeding depth and seed-to-soil contact be a top priority. Planting forage seeds too deep can exhaust the energy reserves in the seed before the new seedling has emerged. This causes poor seedling establishment which can spell problems (increased weed competition, lower forage yields, and ultimately shorter stand life) for the stand. Ideally, forages should be planted about ¼ inch deep. Planting depths greater than ½ inch will decrease forage seedling emergence as much as 50%. Seed-to-soil contact is also important because it ensures that the seeds can absorb adequate water from the soil to germinate. Poor seed-to-soil contact slows water absorption and allows water to evaporate out of the seed. Good seed-to-soil contact requires a fine seedbed (no soil clods) and can be improved with press wheels or cultipacking after planting.

So when you are working the field to plant forages remember that a firm seedbed is needed to regulate seeding depth and a fine seedbed maximizes seed-to-soil contact. Creating a firm and fine seedbed is the whole point of preparing the seedbed and the first steps to successfully establishing a great forage stand.

Market Outlook — John Berry, Lehigh County Educator

chart

Is history worth reviewing? Have the commodity markets reached new, uncharted territory? When should I price my grain?

If we look briefly at the above chart I think there are a couple items to keep in mind as we get the machinery fired up for another exciting spring season. No one can predict the future. Heck, my local weather-person has trouble guessing if it will rain in the next 12 hours. How are we to expect marketing advisors to guess grain prices several months out into the future?

Believing that the historical TRENDS of grain marketing offer some guidance — I use the above chart to identify when might there be seasons of the year to establish some prices on grain. This data suggests to me that perhaps the March, April, May time frame has better odds of a seasonally respectable price than the months of August, September, and October. No matter what the price level is — there are historically trends to consider.

For me personally, all 2007 grain has left the property months ago. I got emotional over those prices. I did miss some $5.00 corn and $13.00 bean sales, but slept quite well on the money that was made. 30% of my expected 2008 harvest for corn and beans are both priced at various levels to date. I really get excited thinking about 2009 crops. If all the price movements up to now have been partially to get sufficient acres planted this year to meet demand. Plus, a Federal election, farm bill negotiations, continued weak U.S. dollar, and the China Olympics will be past. It could be a wide ride if that “overdue” Midwest drought decides to show up! Of course, if the world economy takes a nose dive — all bets are off.

Land Rental Agreement Survey — Andrew Frankenfield, Montgomery County Educator

The Crop Management Extension Group at Penn State Cooperative Extension are asking for your help to benchmark land rent throughout Pennsylvania and it’s counties over time. Currently the average cash rental rate in Pennsylvania according to PA Agricultural Statistics is $48 per acre for cropland and $30 per acre for pasture. From that value it is impossible to determine what the range of cash rental rates are in a specific county and with varying soil types.

This information will to be used internally by Extension and will not be publically disclosed. Responses are anonymous.

These results will not be printed and shared with the public. Thank you.

Please click on the link below to access the short survey http://www.surveymonkey.com/s.aspx?sm=PVCdqb4GNDX_2fc252Mc3rnQ_3d_3d

Contributors: Dept. Crop & Soil Science: Marvin Hall, Ron Hoover, Bill Curran, Sjoerd Duiker, Del Voight and Greg Roth. Extension Educators: Andrew Frankenfield (Montgomery), Dwane Miller (Schuylkill), Kevin Fry (Armstrong), Mena Hautau (Berks), and Mark Madden (Sullivan).

Editor: Kevin Fry

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