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

Vol. 96:5

May 17, 1996

IN THIS ISSUE:

Announcements

Certified Crop Adviser Corner

Production

- Fertilizing Forage Crops after First Cutting
- Frost on Winter Grains
- Dealing with Wet Weather and Late Planted Corn

Pest Management

- Pre and Postemergence Herbicide Applications in Corn
- Register Now for the 24th Annual Weed Control Research Tours at Penn State
- Small Grain Insecticide Changes in the 1997-1998 Agronomy Guide - Correction

Agent Observations

- Dauphin
- Montgomery



ANNOUNCEMENTS

REGISTER NOW FOR THE WEED SCIENCE FIELD DAYS

- Registration form later in document.

PEQUEA-MILL CREEK PROJECT FIELD DAY TOUR - JUNE 11, 1996.

A field day demonstrating pasture rotational lots, pasture watering, cow lanes, farmstead evaluation, streambank fencing, stream crossing, barnyard runoff control, and nutrient management will take place at the Gideon Fisher Farm located at 3321 Old Philadelphia Pike, in Intercourse (Rt. 340 and Pond Road). The tour will run from 9:00am to 2:00pm. For more information and
registration contact the Pequea-Mill Creek Project office at 717-396-9423.


CERTIFIED CROP ADVISER CORNER

CERTIFIED CROP ADVISER EXAM

The next Certified Crop Adviser exam will be held on August 2, 1996. Registration materials must be completed and returned to the national office by June 14. Registration forms and information relating to the exam can be obtained from the national Certified Crop Adviser office at 677 South Segoe Road, Madison WI, 53711-1086. (608-273-8080). I also have a limited supply of registration material. The August exam will be the last time public employees can take the national exam free of charge. The state exam is not free to public employees.

CERTIFIED CROP ADVISER EXAM STUDY SESSION - JUNE 14, 1996

This program is designed to help professionals prepare for the CCA exam on August 2, 1996. Study materials will be provided. Areas in Soil Fertility and Nutrient Management, Soil and Water Management, Pest Management, and Crop Production will be discussed. The discussions will center on sources of information to use when studying for the exam as well as clarifying questions you may have relating to subject matter covered by the national and state performance objectives.

The cost of the session is $65.00 which includes study materials and lunch. For registration information, contact the Short Course Office (814-865-8301) in the College of Agricultural Sciences. Enrollment is limited to 20 participants.

The program will be on June 14, 1996 from 8:30 am to 5:00 pm in room 524 ASI Building on the Penn State campus.

Elwood Hatley, CCA


PRODUCTION

FERTILIZING FORAGE CROPS AFTER FIRST CUTTING

Many farmers routinely topdress their hay fields with fertilizer following the first cutting. Is this a good idea? Whether or not it is a good idea depends on several factors. The most important of these factors is whether the crop needs additional nutrients. For a grass or mostly grass stand, nitrogen (N) will be required for optimum production. You need to supply about 40 lb of N per acre per ton of expected yield. This should ideally be applied between all cuttings based on the expected yield for the next growth period. For example, if you anticipate a second cutting yield of 1.5 tons of grass hay per acre you should apply 60 lb of N per acre after first cutting.

For phosphorus (P) and potassium (K), a soil test is the best guide for making the decision about topdressing. If the soil tests low, a recommendations will be made to build the soil into the optimum range. If the soil is already in the optimum range, a recommendation will be made to offset the anticipated crop removal of nutrients to maintain it in the optimum range. If the soil tests in the high range, no additional nutrients are needed and routine topdressing is not recommended. If the soil test only calls for a relatively small, maintenance, amount of nutrients, the timing of application is not critical. The nutrients can be applied between any cutting or in the fall. This application can be made whenever it is convenient. When larger amounts of nutrients are needed, it is recommended that the nutrients be split into two applications; some applied after first cutting and the rest in the fall. If a split is not possible, the fall application is probably the most critical because of the importance of good fertility to winter survival of the stand.

Potassium fertility management is of particular concern in forages. Forages will typically remove very large amounts of potassium from the soil. This removal is in the range of 40 to 60 lb of K2O per ton of hay harvested. This means that a 5 ton per acre alfalfa crop might remove 300 lb of K2O per acre per year. This reinforces the importance of following soil test recommendations to maintain soil K levels in the optimum range so that there is adequate K to meet this high demand. The second reason that K is important is that most forage crops are "luxury consumers" of K. This means that if extra K is available in the soil, the plants will take it up whether they need it or not. This luxury consumption is a waste of K fertilizer because forage crops may remove 40 or 50 lb more K2O from a high testing soil than they would under an optimum yield fertilization program. This excess K can also result in very high K levels in the harvested forage and thus animal health problems. Animal nutritionists are becoming increasingly concerned about high K levels in forages. This is primarily a concern for dry cows especially those that are close to freshening. The bottom line is that you need to supply adequate K for optimum yield but don't apply excess K which could cause problems with your animals.

Manure can be applied between hay cuttings if soil tests indicate a need for the nutrients. Since legumes don't require supplemental N, the rate of manure application on legumes should be based on not applying excess P and K. Be aware that if the stand contains significant amounts of grass or weeds, the nitrogen in the manure can stimulate the growth of these plants and create competition for the legume. Also, be careful not to physically damage the stand with heavy manure applications. Apply the manure as soon after cutting as possible.

Legumes are fairly sensitive to boron deficiency. Drought conditions are particularly conducive to boron deficiency because of reduced organic matter breakdown. This is also why the boron level in alfalfa is lowest during July and August and why, if boron fertilizer is needed, it should be applied after first cutting so that it is available during this period of low soil supplying capability. If the soil and/or plant analysis indicates a boron deficiency the usual recommendation is 1 to 3 pounds of boron per acre depending on the severity of the deficiency. This is usually broadcast after the first cutting with the topdressing fertilizer. When soil or tissue tests are not taken, the common "insurance" recommendation is to apply 2 pounds of boron per acre when the alfalfa is topdressed with fertilizer. With a coarse textured soil this should be an annual application but on finer textured soils applying boron every 2 or 3 years should be adequate.

Douglas Beegle

FROST ON WINTER GRAINS

We have been getting inquiries about the effect of the recent low temperatures on both winter barley and winter wheat. Reported temperatures ranged between 20 and 30 degrees F. Frost was noted in many fields. What affect will this have on final yield? As with most questions relating to environmental stresses, it depends on many factors and is difficult to predict. The key factors are temperature and stage of plant growth.

Winter grains become more sensitive to cold temperatures as the plants age. This means that plants at Growth Stage (GS) 6 are more tolerant to frost damage then those at heading (GS 10.1). The potential effect, of frost, on yield will probably be the greatest when the head is in the boot (GS 10) through pollination (GS 10.5). Freezing temperatures tend to have the greatest affect on areas that are actively producing new cells. At these stages the temperature needs to drop to around 28 degrees F. before any damage is noted. At earlier growth stages the head is positioned lower in the stem and protected by the canopy. As mentioned earlier, plants at these stages can withstand lower temperatures before yield is affected. In most cases, the main effect of the frost will be partial leaf burn.
What are the symptoms of frost damage? Leaf burn looks very similar to the burn associated with liquid nitrogen applications. Damage to the head will cause the head to have a yellowish-white, watersoaked appearance. They may also have a deformed appearance. A close look at the flower parts will help determine the extent of any damage. The pollen shedding anthers will become shriveled and turn brown instead of having a normal turgid, green appearance. The feathery, whitish stigmas will not open and also will turn brown.

Elwood Hatley, CCA

DEALING WITH WET WEATHER AND LATE PLANTED CORN

Recent rainy weather and cool temperatures have delayed corn planting in much of the state during the first two weeks of May. As a result, the odds are high that much of this years corn crop in Pennsylvania will be planted much later than normal.

Long term planting date response studies indicate that delaying planting until late May reduces grain yields by about 8% compared to early May planting dates. After late May, however, yield reductions become more severe, increasing to about 20% for corn planted in early June. In some of our recent research, silage yields were reduced by about 1-2 tons per acre by delaying planting from May 7 to May 20.

When fields do dry out there are several considerations that corn producers should think about to try to deal with this situation. Concentrating on planting should be a
priority. Reducing additional tillage and switching some fields to no-till could be considered. Also, delaying nitrogen applications until sidedressing could be considered to help speed planting. On optimum or high testing soils, a response to starter fertilizers becomes less likely with delayed planting, so these could be eliminated in some situations if they contribute to slower planting. Relying more on custom herbicide applications could also be an option, but ag chemical dealers are also likely to be behind schedule. One option may be to rely more on postemergent herbicide applications for weed control. With some of the new products on the market, these postemergent programs are a more effective option than they were in the past.

For producers who consider switching to no-till, remember that if it's too wet to plow it's generally too wet to plant. This rule is frequently overlooked in wet, late years. When planting into wetter than desirable soils it's harder to get good seed slit closure. Firming wheels on planters should be adjusted to achieve good seed to soil contact and seed coverage. This is particularly true if using Prowl, 2,4-D or Banvel herbicides. Under wet soil conditions, bubble coulters are more likely to cause sidewall glazing than eight or thirteen wave coulters. Seeding depth in late planted, moist soil conditions should be governed by the herbicide program. If seed coverage is not needed then a shallower than normal planting should lead to a quicker emergence and help the crop "catch up".

Hybrid selection is also a consideration. It is difficult to generalize about hybrids because of the variation in growing seasons and planting dates across Pennsylvania, but most of the adapted hybrids can be planted two to three weeks later than normal and still mature. Consequently, it is generally not necessary to consider switching to earlier hybrids until the 20th to 25th of May in most areas. For growers who were planning to use full season hybrids that need most of the available growing degree days in their area, however, they may want to consider dropping back to some earlier hybrids. Not paying attention to hybrid maturity consideration as planting becomes delayed may lead to more of the immature, low test weight corn problems we experienced in 1992.

In late planting situations, consider the intended use of the crop. Fields planned for grain harvest should be planted first, since they will likely be at more risk for lower yields, high grain moisture and possible lower test weight at harvest because of the shortened growing season. Silage fields may experience lower yields with delayed planting, but often quality is not reduced unless the crop is killed by an early frost. Delaying planting may lead to later silage harvests, however so growers should consider this in making harvest or livestock feeding plans.

We will also likely encounter more conflicts this year with planting corn and harvesting hay. Generally the reduction in feed value from delaying hay harvest a week for dairymen will be greater during late May than the value of the yield penalty from delaying corn planting a week. Consequently, given the choice, dairymen who need high quality feed should probably consider harvesting hay. In early June, yield penalties for corn become greater and changes in hay quality are less significant, so then the edge might go to corn planting.

There are some advantages to later plantings that we should remember. Weed problems may be less with additional tillage and later planting. Preemergence herbicide injury is often reduced. Germination and emergence is much more rapid and we often achieve better stands with later plantings. Remember also that yields are not always reduced with late plantings. In 1989, when only 42% of the Pennsylvania crop was planted by May 30, yields averaged a respectable 103 bushels per acre. Most of our crop yield potential will depend on July and August weather.

Greg Roth


PEST MANAGEMENT

PRE AND POSTEMERGENCE HERBICIDE APPLICATIONS IN CORN

Last year it was dry, this year, because of wet conditions in many regions of Pennsylvania, growers may be forced to delay their preemergence herbicides applications or think about postemergence control strategies. A number of residual herbicides can be applied after planting up until corn and weeds reach a certain size or growth stage. The greatest risk of failure comes with trying to control annual grasses such as foxtail and panicum after they emerge.

Several products are now available to control emerged grasses (Accent, Basis, Pursuit on IMI-Corn only and now Poast Plus for SR Sethoxydim-Resistant Corn only.) Certain tank-mixes containing one of these grass herbicides will provide control of emerged grasses plus residual control. Because of their recent introduction, few residual herbicides are labeled with Basis or Poast Plus in tank-mixture. However, Frontier and Prowl are labeled with Accent and a number of residual products are labeled with Pursuit. For most products, do not apply in liquid fertilizer if corn has emerged. Some preemergence and postemergence considerations are listed as follows.

Maximum corn and weed size for preemergence or postemergence over-the-top (i.e. drops not called for) herbicide applications.
Herbicides Maximum corn size Maximum weed size
a Dual II, Bicep II, and Bicep Lite II labels state application before corn and weed emergence (an early postemergence application supplemental label is still pending).
b May use a reduced rate of Frontier and Accent under certain conditions.
c Accent rate of 1/3 to 2/3 oz/acre and Beacon rate of 3/8 to 3/4 oz/acre.
2,4-D 8 inches varies
Accent 24-inch varies by species
Atrazine 12 inches 1.5 inches
Atrazine + Bladex 90 DF or Extrazine 90 DF 4-leaf 1.5 inches
Banvel @ 1 pint
@ 0.5 pint		 5-leaf or 8 inches
8- to 36 inches		 varies by species
Banvel + atrazine or Marksman 5-leaf or 8 inches before grass emergence or
by tank-mix partner
Banvel or Marksman + Bladex 80W or 90DF 4-leaf 1.5 inch grass
Banvel or Marksman + Dual or Lasso EC 3 inches 2-leaf grass
Banvel or Marksman + Frontier 8 inches 1 inch grass
Marksman + Prowl 2-leaf 1 inch grass
Basis 4-leaf (2 collars) 1 to 2 inch grass
Beacon 4- to 20 inches varies by species
Bladex 80W or 90DF 4-leaf 1.5 inches
Broadstrike +Dual before emergence before emergence
Broadstrike Plus @ 0.25 lb/A (soil)
@ 0.10 lb/A (post)		 spike stage
up to 24 inches		 before weed emergence
2 to 8 inch broadleaves
Buctril up to tassel varies by species
Buctril +atrazine 12 inches varies by species
Clarity 5-leaf or 8 inch varies by species
Dual or Micro-Tech + atrazine, Bullet,
Bicep, Bicep Lite		 5 inches 2-leaf
Dual II, Bicep II, Bicep Lite IIa before emergence before emergence
Exceed 4- to 24 inches varies by species
Frontier 8 inch before emergence or by tank-mix partner
Frontier + Accentb 8 inch 3 inch
Frontier + Beacon 8 inch depends on weed (see Beacon label)
Guardsman 8 inch 1.5 inches
Harness or Harness Extra before emergence before emergence
Permit Layby (last cultivation) varies by species
Princep before emergence before emergence
Prowl + Accentc 6-leaf depends on weed (see Accent label)
Prowl + Atrazine or Prowl + Bladex 90DF 4-leaf 1 inch
Prowl + Beaconc 6-leaf depends on weed (see Beacon label)
Pursuit no statement 1 to 3 inch
Resource varies with tank-mix varies with tank-mix
Scorpion III 8 inches 2- to 4- true leaves
Sencor varies with tank-mix varies with tank-mix
Shotgun 4-leaf or 8 inches small broadleaves
Stinger 24-inch varies by species
Surpass or Surpass 100 before emergence before emergence
Tough varies with tank-mix varies with tank-mix

Bill Curran

REGISTER NOW FOR THE 24TH ANNUAL WEED CONTROL RESEARCH TOURS AT PENN STATE

The Penn State Weed Tours are quickly approaching. The following information outlines the dates, locations, and types of research you can see by attending. If you would like to join us for one or both tours, please call or mail in the registration forms that are attached.

Tour Agenda

July 8, 1996; 9:00 - 2:00 pm - Landisville, PA (Southeastern Field Research and Extension Center, 2 miles NW of Landisville)

------------------------------------------------------------------------------------------------------------

July 9, 1996; 8:30 - 3:00 pm - Penn State Agronomy Farm, Rock Springs, PA

(Meet at the Agronomy Farm, Rock Springs, Rt. 45 west of State College)
Weed control in corn, soybeans, alfalfa, and vegetables
-New and experimental herbicides for corn (AC513,996, Axiom, Balance, Basis, CGA77102II, DPX79406, Exceed, Harness, MON8411, Permit, Resource, Raptor, Resolve, SAN1289, SAN1269H, TopNotch, etc.)
-Mechanical weed control in conservation tillage corn
-Cover crop research
-New and experimental herbicides for soybeans (Action, Authority, Axiom, Cobra, Command ME, Detail, Expert, Stellar, etc.)
-Roundup-Ready soybeans
-Weed control in vegetables


For Landisville (July 8, 1996) and the Rock Springs Tour (July 9, 1996)

Please Register by July 1, 1996

by mailing the registration form to:

Lisa Crytser
116 ASI Bldg.
Department of Agronomy
University Park, PA 16802
(Phone: 814-865-2543)
(FAX: 814-863-7043)

Landisville tour (July 8)

Registration ($7.50) number ___________ amount _________
(includes tourbook and lunch)

Please list name, organization and address of persons included

Name: _______________________ ______________________
Organization: ______________________________________________

Address: ______________________________________________


Rock Springs tour (July 9)

Registration ($10.00) number ___________ amount _________
(includes tourbook and lunch)

Please list name, organization and address of persons included

Name: _______________________ ______________________
Organization: ______________________________________________

Address: ______________________________________________


Total amount enclosed $____________


SMALL GRAIN INSECTICIDE CHANGES IN 1997-1998 AGRONOMY GUIDE - CORRECTION

Warrior is now registered for use against cereal leaf beetle in wheat. This was inadvertently ommitted from the last issue of this newsletter.

Steve Spangler & Dennis Calvin


AGENT OBSERVATIONS

As of today - May 13, 1996, very little, in some cases none, corn has been planted both in Upper and Lower Dauphin County. Weekend rainfall of nearly 2 inches will keep equipment out of fields at least 2 -3 more days under the best situations. In many cases, excessive field moisture conditions have prevented many field preparations from occurring including manure hauling, primary and secondary tillage, and weed control applications. In addition soil temperature conditions remain cold and little seed emergence is occurring.

Special concern has been noted of the onset of maturity of grass fields and the soon to be bud stage of alfalfa. This leads to time constraints on labor and equipment to decide to plant corn or chop forages.

Delay in early burndown herbicide application has allowed winter annual weeds and perennials to get a jump on spring development. In addition, Burndown herbicide activity has been slowed by the cooler temperatures.

The cool-wet spring has not delayed development of burcucumber seedlings as well as some other weeds. New burcucumber shoots are already in the 3-leaf stage.

Pasture regrowth has been slow. Graziers are not having much of a problem keeping stands grazed, in some cases regrowth has been slowed due to overgrazing as producers are utilizing pasture to reduce reliance on purchased feeds and hay crops.

Paul Craig, Dauphin Co.



As of May 14, weather continues to be a challenge for farmers in Montgomery County. Very little crop work has been completed as our wet soils have not had a chance to dry out. For those few that planted rye for a forage to make up for last years drought, harvest has been a wash out. Mowed rye was followed by ample rainfall or unmowed rye is now in full head. Forage and grain supplies are very tight. We have ample forage growth in the fields for a first cutting but a string of dry days will be necessary for succssful harvest.

We also had a hard frost this morning which I believe did not have a negative impact on producers since most of the seed is still in the bag. On the positive side, the frost hopefully killed some annual grass weeds that germinated earlier this year.

For the few graziers, keeping up with pasture growth has been extremely challenging this spring. Pasture went from 3 inches to 18 inches over a very short time. Many graziers would like to harvest surplus pasture but the weather is not cooperating. Mud is also a problem on fields that have been recently converted to pasture. A good lane system is critical in wet periods to get the cows to the grazing paddock.

Timothy J. Fritz, Montgomery Co.

William S. Curran
Associate Professor Weed Science
email: wsc2@psu.edu

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