Field Crop News

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

April 15, 2005    Vol. 05:02

IN THIS ISSUE:

Mark Your Calendar

Weather Outlook

Production

Pest Management

MARK YOUR CALENDAR

Conservation Tillage Demonstration Field Day

Hosted by Solanco Young Farmers and Penn State Extension Agronomy Team. Tuesday, April 19, 10 a.m. - 2 p.m. Just south of the Lancaster County/Cecil County border.

Come and see the conservation tillage equipment working in the fields. See several different methods of incorporating manure while keeping the residue on top for optimum yields. Local dealers are demonstrating no-till, minimum tillage, deep rippers, mulching, and planting equipment. Thanks to the generous support from the dealers, sandwiches, desserts, and hot and cold drinks will be provided.

Directions: Take 222 south of Peach Bottom into Maryland about 1 mile. Turn right onto Oakwood Road. Go 0.8 mile, farm on left. Watch for signs!

Questions: Call Axel Linde: 717-529-6963 or axellinde@aol.com.

Certified Crop Advisor Workshop Planned for May 13

Many professions require individuals to demonstrate a level of competency before starting work in that field. For example, a degree in medicine requires individuals to pass certification exams. The public is thus assured health services purchased from certified individuals who meet a standard of excellence. In 1993, the American Society of Agronomy (ASA) implemented a certification program for crop advisors, who make crop management recommendations to producers. Likewise, when individuals certified by ASA make recommendations impacting the nationÕs food supply, as well as the nationÕs soil and water quality, the public is assured recommendations are in the best interest of agriculture and society. A producer who hires an ASA Certified Crop Advisor (CCA) can be confident the recommendations made by the CCA will be in accordance with the producer's crop management goals and within the framework of resource restrictions.

While producers benefit from hiring CCAs, advisors benefit from the added prestige associated with certification. The CCA must pass comprehensive state and national exams covering nutrient management, soil and water management, integrated pest management and crop management; the CCA must demonstrate at least two years of crop advising experience; they must keep pace with advances in agricultural production through continuing education; and must adhere to a code of ethics that places grower profitability and natural resource protection above all else. Thus, the certification program provides CCAs with the credentials and professionalism important for maintaining respect on the farm, within industry, and within the agricultural agencies supporting crop production and protecting natural resources.

On May 13, Penn State faculty and staff from the departments of Crop & Soil Sciences, Entomology, and Plant Pathology will hold a one-day workshop at University Park to prepare individuals planning to take the CCA exams in Harrisburg on August 5. The workshop will be held in Room 107, Agricultural Sciences and Industries Building. It will start at 9:00 a.m. and end at 5 p.m. There is no charge for attending the workshop. To register, call or e-mail Lisa Crytser (814-865-2543, lac8@psu.edu). Everyone serving or planning to serve the crop production industry should take this opportunity to become certified.

The registration period for the August 5 exams is May 2 to June 17. The fees to take the state and national exams are $100 and $125, respectively. For more information about the CCA program visit the ASA website (www.agronomy.org) or contact Amy Bradford (abradford@pennag.com). Because the average passing percentage over all testing opportunities is only 60%, the one-day workshop may provide the advantage you need for certification success.

Jan Pruss, jap5@psu.edu
Crop Management, Crop and Soil Sciences

WEATHER OUTLOOK

What began as a very wet month has suddenly turned much drier. A blocking pattern in the jet stream is shunting all the moist disturbances to the south of Pennsylvania and this will not change until the middle of the coming week (April 20). The combination of cool nights, sunny days and very low humidity will keep the brush fire risk very high for the next few days.

It will turn warmer early next week with readings likely to reach well into the 70's and lower 80's between April 20-22. Any gusty winds will make the fire risk extreme in the western and northern parts of the state. A spell of warm, humid conditions is expected before a cold front pushes across the region next Friday. Showers and perhaps the first widespread outbreak of thunderstorms should accompany the change to cooler conditions.

Temperatures will drop below seasonal levels during the period April 23-25 before another quick warm-up at the end of the month. Precipitation should average below normal for the second half of April. The outlook for the summer period (Jun-Aug) favors a cooler than average summer with at least one month with well above normal rainfall, probably in June.

Paul Knight, pgk2@psu.edu
Pennsylvania State Climatologist

PRODUCTION

How Late Can Forages Be Planted?

The answer depends on the expected moisture and temperature during the first 60 to 80 days after seeding. Unlike annual crops, with perennial forages we are not as concerned about the crop maturing in the fall. The major limitation with late forage seedings in the spring is moisture and temperature during establishment. If the seedlings emerge and then the weather turns dry and/or hot, the seedling development will be delayed at best or the seedling killed at worst. Delayed seedling development allows for greater weed invasion and competition than if the forage crop was not delayed.

Traditionally, forage grasses should be seeded by early May because the hot weather in June and July delays their growth. Waiting and making an August seeding, rather than a late spring seeding, is a safer route to achieve a vigorous, weed free forage grass stand. Late-spring seeding an alfalfa crop, however, is more site specific. If the field is in an area that holds moisture well and you anticipate frequent rains into July, then seeding into mid May can be considered as an option. Keep in mind though that every day that seeding is delayed, your risks increase. If the field where the alfalfa is to be seeded is normally a droughty field, then it is recommended to wait until August to seed.

Marvin Hall, mhh2@psu.edu
Forage Management, Crop and Soil Sciences

Tillage Options This Spring

We are all thankful for some great drying weather lately. This allows us getting field work done at appropriate soil moisture conditions. As a rule of thumb, no field work should take place when the soil is at or wetter than the "plastic limit". This is a soil scientist's term to indicate that the soil is so sticky that it stays together when kneading a ball. When soil is at the plastic limit or wetter, it is very compactable and bad things start to happen: plow pans form below tillage tools, side-wall compaction occurs in seed slots, and the soil is compacted by tires, steel wheels and hoofs. The effects of these different types of compaction then show up in restricted root growth in the crop thatÕs planted, so it is important to respect this "law of nature".

Modern chisel plows are often set up to combine primary and secondary tillage in a one-pass operation.

Irrespective of the type of tillage that you do, it is recommended to maintain 30% residue cover at the soil after planting. This limit has been agreed upon globally as the cut-off point between conventional and conservation tillage. Having more than 30% residue cover reduces soil erosion to somewhat acceptable proportions. It is very hard to obtain 30% residue cover with any type of tillage after crops such as corn silage, soybeans, and small grains where both grain and straw were harvested. In these cases no-till is a shear must to qualify for conservation tillage. After corn grain harvest, there is a lot more residue, especially this year after the bumper crops that were harvested. In that case the type of tillage determines whether 30% crop residue cover will be achieved or not. Moldboard plowing usually reduces residue cover to less than 5%. It may be possible to attain 30% residue cover with chisel or disk plowing, but then the secondary tillage operation becomes crucial. Both mulch tillage options followed by disc harrowing mostly result in less than 30% residue cover. It is therefore recommended to use a field cultivator instead of a disk for secondary tillage operations. It may also be possible to use a rotary harrow for this task. Some of the newer chisel plows combine primary and secondary tillage in a one-pass operation because the secondary tillage tool is mounted behind the chisel shanks.

As with anything in farming, one has to question why one does tillage: it costs money, and has a lot of negative side-effects. So if itÕs possible, it is much better to use no-tillage.

Sjoerd Duiker, swd10@psu.edu
Soil Management, Crop and Soil Sciences

No-till Forage Establishment

Intensive tillage for forage establishment can easily lead to severe soil loss, as in this orchardgrass field in Northwestern Pennsylvania.

We recommend no-tillage for most soils in Pennsylvania, but at least on all well- and moderately-well drained soils. No-tillage saves soil, results in increased infiltration, reduced evaporation, increased soil life and reduced costs and time needed for crop establishment. Many farmers have at least been exposed to no-till soybeans and corn, but no-till forages such as grass and alfalfa are still rare. Tillage surveys indicate that only 10% of forages are established no-till in Pennsylvania.

However, no-till forage establishment has many benefits over establishment in tilled soil. With tillage, the seedbed needs to be almost pulverized or seed-to soil contact and seed depth control will be insufficient. The number of tillage passes is therefore considerable for forage establishment.

For successful no-till forage establishment it is important to have a moderate amount of residue at the surface and not place the seed deeper than 1/4 of an inch.

The intensive tillage leaves recently established forage fields very vulnerable to erosion as well as crusting. With no-till, it is much easier to obtain good seed-to soil contact and maintain depth control. The drill needs to be set right so seeds are not placed deeper than _ inch. To maintain good seed depth control, it is not recommended to have a large amount of crop residue at the soil surface, and the residue needs to be distributed uniformly. It may be best to bale corn residue and use it for bedding prior to no-till forage establishment.

Sjoerd Duiker, swd10@psu.edu
Soil Management, Crop and Soil Sciences

Soil Erosion: Still Number 1

Soil erosion is still our number one water polluter. This satellite image (courtesy NASA MODIS rapid response) was taken 10 days ago, on April 5th.

Satellite image showing brown water in the Chesapelake Bay.

It clearly shows the large quantity of brown water flowing out of the Susquehanna River into the Chesapeake Bay. This sediment seriously threatens Bay ecology. According to the Chesapeake Bay Tributary Strategy, released in December 2004 by the Department of Environmental Protection, Pennsylvania agriculture contributes 72% of sediment load to the Bay. This spring many decisions are made that influence soil erosion. Tillage is the main cause of soil erosion from agricultural fields. Conservation plans help to keep erosion in check, but the best way to control erosion in crop production is to keep soil continuously covered with crop residue or living vegetation. In 2004, only 36% of planted acres in Pennsylvania used conservation tillage methods (>30% residue cover after planting). There is a lot of potential for increase because all crops on all soils in Pennsylvania can be planted with some form of conservation tillage without any yield reduction.

Sjoerd Duiker, swd10@psu.edu
Soil Management, Crop and Soil Sciences

RYE COVER CROP MANAGEMENT

In a 3-year study in Centre County, rye killed in early-boot stage resulted in a 10 bu/A corn yield increase, whereas rye killed in late-boot stage did not reduce corn yields.

Cereal rye is our most common cover crop. It has a lot of potential for use after crops that leave little crop residue, such as corn silage, soybeans, and small grains. Benefits of rye include erosion reduction, protection of nitrate from leaching, provision of mulch during the following growing season, weed reductions and additions of soil organic matter and root biomass to the soil. However, there are also reports of drawbacks of rye, such as allelopathic effects on the following crop (mostly corn), hairpinning problems, and soil moisture depletion. In a 3-yr study on limestone valley soil in central Pennsylvania we learned the following key lessons: (1) on average, we recorded a corn yield increase of 10 bu/A due to rye killed in early boot stage (when it is approximately 12 inches tall) compared to late kill or no rye?; (2) rye killed in late boot stage (fully headed out, but before it sets viable seed) did not result in a corn yield reduction compared to having no rye, despite the fact that the corn was planted approximately 10 days later; (3) we found no benefit of doing zone-tillage in rye with the three-coulter system (instead it gave us a heap of trouble); (4) weed control was excellent with both pre- and post-emergence herbicides primarily because we had low weed severity to start with. We observed a reduced bulk density due to rye killed in late-boot stage in the year we measured it (the first year). Some experimental details that may have contributed to our success with rye management were that we had a low residue crop preceding it (oats, straw harvested), that we had no nitrogen deficit because we fertilized rye with 70 lbs/A of N in March, and we killed the rye with 0.75 lb acid equivalent/A glyphosate (22oz Roundup Weathermax) 7-10 days prior to planting corn. We established rye at 2 bu/A of seed at the end of October (first year) and beginning of October (2nd and 3rd year). We observed much higher rye biomass production in the second and third year than the first year. We therefore believe you get the best of two worlds if you kill rye established early when it is 12 to 16 inches tall. This will guarantee high biomass production and probably a reduction in soil density and boost in corn yield. Killing rye later would increase its biomass production, but you run into more potential for trouble with hairpinning and untimely planting. We had no bad experiences with allelopathic effects of rye on corn, something that still needs further investigation to predict it. However, later killed rye (after head emergence) and planting crops prior to or immediately following herbicide application (without a 7 to 10 day delay) will increase the likelihood for negative effects on corn and other crops.

Sjoerd Duiker, swd10@psu.edu
Soil Management, Crop and Soil Sciences
Bill Curran, wcurran@psu.edu,
Weed Science, Crop and Soil Sciences

PEST MANAGEMENT

HERBICIDE UPDATE: CALLISTO RECEIVES FEDERAL LABEL FOR USE ON SWEET CORN

Callisto 4SC (mesotrione) herbicide has been used in field corn since 2001, and just recently, Syngenta announced that it has been labeled for use on sweet corn. It can be applied either pre or postemergence and has good activity on a number of broadleaf weeds that are a problem in sweet corn. If used pre, Callisto will likely be tank-mixed with a pre-grass herbicide and atrazine to broaden the weed control spectrum. The typical preemergence use rate is 6 fl oz/acre, however research at Penn State has shown very good activity on lambsquarters and velvetleaf with rates as low as 3 fl oz/acre. Callisto will commonly be used postemergence in sweet corn at a rate of 3 fl oz/acre plus nonionic surfactant (NIS) or crop oil concentrate (COC). NIS is recommended instead of COC to minimize crop injury. Do not add N-fertilizer (UAN or AMS) to the spray solution or severe crop injury may occur. Certain sweet corn varieties are more sensitive to Callisto than others. Lumax and Lexar are expected to be labeled for use in sweet corn, however no information has been released.

Dwight Lingenfelter, dxl18@psu.edu
Weed Science, Crop and Soil Sciences

Burcucumber Management in Corn and Soybean

A Burcucumber seedling.

Burcucumber (Sicyos angulatus) is a serious weed problem in agronomic crops in many areas of the Northeast.

Last season was an excellent growing season for burcucumber which likes frequent rainfall and moist soil. Originally found along stream banks and other damp, shady areas, burcucumber has invaded river bottom and upland fields and has continued to increase it's foothold in the Northeast.

Burcucumber can be difficult to manage because the seed can germinate from mid May through early August and the late emerging seedlings are difficult to control in emerged crops. We have had several experiments that examined burcucumber control and management in corn and soybean. This research revealed that no-till in combination with postemergence herbicides generally can lead to improved burcucumber control. No-till tends to encourage a more uniform burcucumber seedling emergence and can reduce successful emergence and weed density. Tillage buries some seeds at lower depths and seems to prolong the germination pattern. With the lack of effective residual control, these later emerging seedlings can be difficult to manage. Although no-till systems may reduce burcucumber infestations over a period of time, effective post control must be used in combination.

In corn, we tested a number of herbicide treatments and combinations. In short, season-long control of burcucumber is difficult on heavier soils and in years with frequent rainfall. At best, 3 to 6 weeks of residual control can be obtained with the more effective herbicide treatments. Although several soil applied herbicides have activity on burcucumber (atrazine, Balance, Lumax/Lexar, Princep, etc.), they generally require some follow-up action postemergence. One of the more effective programs POST in corn includes tank mixing atrazine at the highest allowable rate (no more than 2.5 lb active ingredient per acre per year in combined soil applied and POST applications) with other effective herbicides. This generally means adding 1.5 to 2.0 lb of atrazine to the POST program, or making split application timings to improve control. In general, timing of the post application should coincide with optimum weed coverage and before crop safety is reduced (V3 to V5 corn depending on the product). Remember that atrazine must be applied before corn reaches 12 inches in height. In our research, prosulfuron, the active ingredient in Spirit (and formerly Exceed), was one of the more effective POST herbicides. In addition, primisulfuron (active ingredient in Beacon and a component of Northstar) provided reasonable control. Several herbicides are also effective at killing emerged plants (Buctril, glyphosate, Liberty, Marksman, etc.), but residual control can be an issue. See Table 2.2-8, ÒEffectiveness of corn herbicides on grasses, grasslike species, and broadleaf weedsÓ in the 2005-2006 Agronomy Guide (http://agguide.agronomy.psu.edu/) for specific performance ratings.

In soybean, there are no effective soil applied treatments for season-long control of burcucumber. POST glyphosate alone can control burcucumber as long as the weed is relatively small (less than 12 inches) and the soybean crop is competitive. Planting in narrow rows will help ensure earlier canopy closure and more effective suppression. Tank mixing 0.33 oz Classic with glyphosate will improve control of emerged plants. Higher rates of Classic (0.66 to 0.75 oz product per acre) will provide some residual control, but are not labeled in combination with glyphosate. Other soybean herbicides (Blazer, Cobra, Harmony GT, Flexstar, etc.) have activity on burcucumber, but will not provide residual control.

In summary, burcucumber is still a difficult weed to manage in corn or soybeans. Control with herbicides can be marginal in these crops, so with severe infestations, crop rotation and reduced tillage systems should be seriously considered as the foundation for longer-term management.

Bill Curran, wcurran@psu.edu
Weed Science, Crop and Soil Sciences

Landscape Maps for Field Crop Insects

Landscape maps web site.

The field crop insect landscape maps are now available on-line at the Department of Entomology webpage: http://www.ento.psu.edu/extension/fieldcrops/predictionmaps.htm or directly at http://psu.zedxinc.com. The landscape maps of insect development show the most advanced life stage of the pest predicted at a site. For instance, the light brownish area represents where at least 5% of the population has entered the egg stage (following figure). The darker brown (chocolate colored) area indicates that at least 5% of the population has hatched into the 1st instar and the first evidence of leaf feeding should show up. In this example, if 5% of the population has entered the 1st instar then 95% of the population is still in the egg stage. Later in the season, the population will be distributed across multiple stages of development, but the color on the map at the location indicates the most advanced stage of the pest at the site. These maps are designed to provide an early warning of when a life stage is approaching that should stimulate scouting and possibly control activities in the area. Maps are available for alfalfa weevil, corn rootworm, European corn borer and common stalk borer. We hope to have a model up and running for soybean aphid by mid-June. In addition to the listed insects, maps are available for seasonal degree days, departure from average degree day accumulations, and eight weed species. Remember these are only predictions of pest life stages and the timing may not be perfect. As mentioned earlier the maps are only to alert you to when key stages of the pest may be present and not for precise timings of management activities. The maps are updated daily with new temperature data and up to seven day forecasts of development can be generated.

Dennis Calvin, dcalvin@psu.edu
Entomology