CMEG Crop Management Extension Group

Field Crop News

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

April 21, 2009    Vol. 09:07

IN THIS ISSUE:

Weather Outlook — Paul Knight, Pennsylvania State Climatologist

Most of the state received between a quarter and three—quarters of an inch of rain during Monday with the lower Susquehanna Valley measuring more than an inch and the northwest plateau having barely a quarter inch. Clouds and showers will dominate the western half of the state on Wednesday as chilly winds return. Snow will fall above 2,000 feet in the Laurel Highlands and northwest mountains during the morning hours. The eastern half will notice gathering clouds and some sprinkles in the afternoon on the hilly terrain. Temperatures should be below seasonal levels on Wednesday and Thursday, though abundant afternoon sunshine on Thursday will boost readings closer to average maximums. From Friday into Tuesday, there will be a mini heat—wave as daytime readings reach the mid to upper 70’s in the mountains and 80’s in the remainder of the state. Skies will be mainly sunny and at first the air mass will be relatively dry. However, humid air will arrive on Sunday and it may become uncomfortably warm on Monday and Tuesday east of the Appalachians as readings reach the upper 80’s. This marked warm spell will tip the scales so that April will end up averaging above normal for Pennsylvania (as of today, most of the state is near to slightly below normal). A cold front will bring scattered thundershowers on Tuesday and the month will end seasonably cool and probably damp.

The overall outlook for May is drier than normal with several cool spells such that an unusual late frost is possible in the southern or central sections from May 14–22. Odds favor warmer than average temperatures in June and above average rainfall during either July and/or August. There are now indications that the summer will average warmer than normal (Jun–July–August).

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

Taking First Cutting of Alfalfa Early — Marvin Hall, PSU Forage Specialist

Very soon alfalfa will start showing some buds in the southern part of the Pennsylvania. Producers will be asking if they should harvest for top quality or wait for it to get a little more height (more yield) before taking that first cut.

In 2005, a joint project was started in Idaho, Wisconsin and Pennsylvania to answer that question. We seeded three different alfalfa varieties and harvested them over a 3–yr period. There were no differences among varieties or years so data were combined. Delaying harvest in the spring increased yield by only 290 lb/a/day but decreased RFV (relative forage quality) by 5 units each day and NDFD (neutral detergent fiber digestibility) by 0.2 percentage units each day.

Change in yield and NDFD for each day harvest is delayed in Pennsylvania.
Season DM Yield (lb/a/day) RFQ (units/day> NDFD (%/day) lb/a/day forage increase
per % decrease in NDFD
Spring 290 -5 -0.1 1-5-
Early-summer 60 -5 -0.7 80
Mid-summer 100 -4 -0.2 530
Late-summer 40 -4 -0.4 80

Taking spring harvest a little early will provide optimum quality and possibly crash weevil populations in the field. The decrease in yield for the first cut could be regained in the 2nd harvest if there is sufficient moisture to keep the alfalfa rapidly growing before the temperatures get too high.

Watch for Alfalfa Weevil — Marvin Hall, PSU Forage Specialist

A few areas of the state are reporting limited alfalfa weevil damage already. The relatively mild winter didn’t reduce the overwintering population so they could potentially be a big problem this spring. In addition, don’t overlook scouting for weevils after the first cutting. In the hot spots they could still be a problem after first cutting if we get cool weather.

Starter Fertilizer for Corn on High P Soils — Douglas Beegle

A common question these days, is do we need starter on soils with above optimum soil test P levels? We did a study on this with over 40 on—farm experiments over 3 years on high P testing soils. Overall we saw a significant yield increase only on about 20% of the fields and the average response to starter on these soils was about 2–3 bu/A. We did see a significant early growth increase on almost 40% of the fields, but there was little connection between this response and final yield. The bottom line is that the probability of getting an economical response to starter fertilizer on high P testing soils is pretty low. At a 20% response rate you are only getting a benefit on average 1 out of 5 times that you apply starter and that one time must pay for the starter the other 4 times when you do not get a benefit. With 2–3 bu/A response the one time you get a benefit, this is not usually economical.

So what are the recommendations? On low or optimum testing soils, use a starter. See Agronomy Facts 51 “Starter Fertilizer” for complete details on starter fertilizer management. On high testing soils you can probably eliminate starter fertilizer or there are a couple of other options. We also tested ammonium sulfate alone as a starter and found that this material provides as good or better response as regular complete starters on these high testing soils but it does not add additional P. Also, most of the cost of the ammonium sulfate starter can be offset by reducing broadcast or side dress nitrogen proportionally. So here is an option if you want to cover yourself so you don’t miss the occasional starter benefit, but it will not added excess P, and it is economical if you can reduce other N applications accordingly. A low rate of ammonium sulfate (~100 lb/A) is all that is needed to get the starter benefit. However, farmers without manure or forage legumes in their rotation will often find an additional benefit to including a significant amount of N (~ 50 lb/A) at planting time. At this higher rate of N make sure the fertilizer is placed 2” away from the seed to avoid injury.

One other option that is becoming more popular for farmers who don’t want to completely eliminate starter, even on high testing soils, is to use an in—row or “popup” fertilizer. With a popup you can go to very low rates, 3–5 gal/A is usually plenty. In fact, you need to be careful that you don’t put too much in the row or you can cause injury. You should not apply more than 10 lb/A of N + K2O directly with the seed.

Example:

5 gal/A 7-21-7 @ 11.2 lb/gallon = 56 lb of fertilizer applied/A
7% N: 0.07 × 56 = 3.9 lb N/A
7% K2O: 0.07 × 56 = 3.9 lb K2O/A
Total N + K2O = 7.8 lb/A >>>Safe<<<

Also, urea and DAP should be avoided as much as possible for direct application with the seed (See Agronomy Facts 51 “Starter Fertilizer” for details). Generally pop—up starter gives similar or sometimes even better response than with much higher rates of traditional starter fertilizer. Popup does require a different set up on the planter and usually involves going to a liquid fertilizer but it can be a very effective and economical program.

Starter fertilizer is an important practice in corn production, especially for early planting in cold, wet soils and at lower soil fertility levels. However, you may want to reevaluate your starter program on high testing soils and consider some of the alternative discussed here.

Chlorophyll Meter N Test — At Planting Considerations — Douglas Beegle and Jonathan Rotz

The chlorophyll meter is a tool that can be used in some situations just before side dressing to significantly improve N side dress recommendations. The recommended procedures for using the chlorophyll meter must be strictly followed if the results and recommendations are to be valid. There are several critical considerations that must be addressed at planting time if you plan to use the chlorophyll meter test at pre-side dress time. The most important of these is that the chlorophyll meter cannot be used if more than 15 lb fertilizer N/A was applied at planting, particularly as a starter. The reason for this is that 20–30 lb of N applied at planting can result in corn looking good to the chlorophyll meter at pre-side dress time thus indicating that no additional N is needed, when in reality there was just enough N to get to this stage of growth but not enough N to meet the total needs of the crop.

For best results a high N reference area should be established shortly after corn planting in fields to be tested. This high N reference area can be small (4 rows × 30 ft for example). The N rate applied to this area is not critical as long as it is more than enough. For example, for 4 rows × 30 ft high N reference area, you would need to apply 4 lb of urea or 8.5 lb of ammonium sulfate to the high N reference plot area. For a different size area or different N fertilizer use the following formula to determine how much fertilizer to apply to the high N reference area:

Area (ft2) × 0.005 ÷ Fertilizer N Analysis (as a decimal)

Example: (10 ft × 30 ft) × 0.006 ÷ 0.46 (urea analysis as decimal) = 3.9 lb urea

If you do not establish a high N reference area, you can still use the chlorophyll meter test on fields with a significant amount of manure or following a forage legume, but again with less than 15 lb of fertilizer N applied. Without a high N reference plot, two readings about a week apart may be necessary at pre—side dress time. Only one reading will be necessary if you have a high N reference plot. Both methods will give acceptable results but using the high N reference area method is usually a little more reliable.

All of the details for using this test are available in a new revised factsheet on using the chlorophyll meter, Agronomy Facts #53 (Revised) The Early-season Chlorophyll Meter Test for Corn, which is available on the Crop Management Extension Group (CMEG) Web site. This factsheet updates the procedure for testing fields with a high N reference area and includes the new two-step procedure for fields with recent manure or a forage legume without a high N reference area. There is also a video demonstrating how to use the chlorophyll meter at that same website.

The PA—PIPE System: an online tool for tracking timing of potential pests — John Tooker, PSU Entomology Specialist

Activity of many pest species can be reliably predicted based on temperature and weather data. Therefore, it would be helpful for growers to have a tool they could use to determine whether certain pests can be expected in their area any time soon. Fortunately, the College of Agriculture at Penn State has been investing in a system that can do just that—help predict when certain pest species should be active. The system is known as the PA-PIPE, which stands for Pennsylvania Pest Information Platform for Extension and Education and it can be accessed through a College of Agricultural Sciences Web site (http://agsci.psu.edu/news/spotlight/pa-pipe) or directly (http://pa-pipe.zedxinc.com/cgi-bin/index.cgi?) A Google search on ‘PA-PIPE’ will also easily find the site.

This system offers a series of maps of PA which display useful weather-related information, such as degree-day accumulations, two-inch soil temperature, and corn and soybean phenology. This weather-related information contributes to a series of maps showing the expected development of some insect and weed pest species. All these maps are updated continuously based on current conditions and years of data. For example, below is a map for 21 April 2009 showing expected activity levels of alfalfa weevil. This map was produced by knowing the rate of development of alfalfa weevil at various temperatures and the PA—PIPE models differences in developmental rates expected for all parts of the Commonwealth. The map legend reveals that first instar weevils are active over the majority of the southern portion of PA:

example map

This information is useful because it indicates that growers should be on the lookout for weevil larvae in their fields and if damage becomes evident, the fields should be sampled to determine if treatments make economic sense.

Below is a list of some of the information currently available on the PA-PIPE. We are working to increase the amount of information the system provides and this list will grow in time. It is worth mentioning that many damaging insect species are not on this list because they are migratory. These species need to be trapped in significant numbers before their development in the state can be predicted. We are starting to address this issue and this year we are trapping for black cutworm, so that it may be added to the system (a previous newsletter article addresses the black cutworm monitoring program.

Maps available on PA-PIPE that might be of interest to field/forage crop growers:
(Maps relevant to fruit and vegetable growers are also available.)

Weather

Crop Phenology

Insects

Weeds

Are rootworm transgenics necessary in second-year corn? — John Tooker, PSU Entomology Specialist

We had an interesting question that was posed to one of our county educators and we thought some folks might benefit from the topic. The educator in the western part of PA was asked if there are any recommendations for corn rootworm-management needs for secondyear corn when transgenic rootworm corn was used in the first year. The grower questioned whether there was a reduced risk for corn rootworm damage in that second year of corn because the first-year transgenics would have significantly reduced rootworm populations; therefore, perhaps transgenics would not be necessary in the second year and the farmer could rely on a soil insecticide.

The answer to this question depends largely on regional populations of corn rootworms. The amount of egg-laying in that first-year corn field is governed by regional rootworm populations not the presence of Bt corn. If the regional population of rootworms is large, there is a good chance that adults will fly in and eggs will be laid in the first-year corn field. Rootworms then, possibly in high numbers, could be present the second-year field. Bt corn does not appear to kill adult rootworms so even if adults fly into the Bt field and feed on silk and pollen, they will remain viable and able to lay eggs. It may be an unsatisfying, but as is often the case, the answer depends on the numbers and it might make sense to use rootworm transgenics in second year corn.

Planting into wet soil? — Sjoerd Duiker, Soil Management

Now that the minimum soil temperatures (at 2" depth, measured early morning) approach or exceed 50 degrees, corn can be planted. However, with the recent precipitation the question comes up regarding if soil moisture content is too high to get started. What are some of the factors regarding too wet soil to look out for?

An easy guide of too wet soil is when you can easily make a ball of soil when you grab a handful of soil from the top 2 inches of the soil, then the soil is too wet for planting. What are the results of too wet soil at planting? — Sidewall compaction. Sidewall compaction is caused by the double-disk openers and restricts the radicle and seminal root growth of corn. The result is that the early root system only develops in the seed slot and does not penetrate into the surrounding soil matrix. The resulting root growth is often described as “Mohawk roots.”

An effect of limited early season root development can be early season deficiency of potassium and phosphorus because the seedling roots cannot access these nutrients. In no-till, the seed slot may stay open when planting in wet soil. The reaction is often to increase pressure on the closing wheels. The highly compressed soil above the seedling may inhibit germination and lead to curled-up seedlings below the soil surface. When it gets dry after planting, the seed slot can also crack right back open, exposing the seed and germinating seedling to the vagaries of nature.

Coulters can help somewhat to alleviate planting issues in moist soil. Using fluted coulters will be your best bet. Bubble coulters are the worst because they compress the soil even before the double disk opener comes through. Row cleaners do nothing to dry the soil at planting, so they are not to be looked at for help (they may help to avoid hair-pinning and early warming of the soil, though). Depth control wheels have been developed that have a ‘dimple’ next to the double—disk opener, avoiding putting additional pressure on the soil right next to the seed slot. Spiked (also called &8216;spading’) or ‘posi’ closing wheels have been developed that may reduce problems with planting in soil with sub-optimal moisture content. Pictures of the planter attachments can be accessed on-line or in our publication “Steps toward a Successful Transition to No-Till.”

Weed Management Tidbits: Forage weeds, orchardgrass burndown, and cover crop issues — Dwight Lingenfelter, PSU Weed Science

Spring Seeded Forage Weed Control Considerations.

For those of you who have planted or will soon plant forages (alfalfa and/or grass) here are a few options to consider for weed management.

Orchardgrass Spring Burndown Hints.

As always, fall applications of glyphosate are much better than spring applications for orchardgrass sod burndown. For those who want to control orchardgrass (or quackgrass) in the spring here are a few considerations:

Cover Crop-friendly Herbicides.

If you plan to plant a cover crop after the crop has been harvested this fall, it is best to consider now which herbicides may cause problems in getting the cover crop established. At this point, not much research has been conducted on specific rotational restrictions for various cover crops. Even many herbicide labels do not provide specific details about what cover crops can be planted after an herbicide treatment earlier in the season. Cereal rye is one of the few common cover crops that will be listed on a product label. Refer to the Agronomy Guide Table 2.2-17 and 2.4-15 or the herbicide label to determine which products have ≤4 month rotation restriction for covers such as cereal/winter rye, field pea, clover, oat, and sorghum/sudan. There is no listing for hairy vetch but by looking at the alfalfa restrictions you can get a pretty good idea of which herbicides may cause potential injury. Covers such as canola/rape, mustards, and buckwheat can be difficult to determine if herbicide residuals will cause a problem. As far as atrazine, if less than 1 lb/A has been applied, rye and hairy vetch should be able to establish in the fall. Until more research, is done on herbicide residuals and cover crop establishment, these are the best guidelines we can provide at this point.

Ryelage Harvest — Paul H. Craig Dauphin County Extension

Last week in the lowest parts of Lancaster County winter annual rye was above my knees in many fields. Producers in that part of the state were getting ready to mow this crop as soon as the fields dry out and some wilting conditions arrive. This should be late this week or early next week.

To ensure high quality ryelage harvest, producers must have harvest equipment ready to go. Quality of ryelage rapidly decreases with maturity and one day in harvest delay can make the difference between high quality and average to poor quality forage. If producers rely on custom harvesters, these individuals need to be contacted now to plan approximate harvest schedules.

Timing of ryelage harvest is critical to ensuring high quality forages. Waiting until head emergence is too late as the rapid maturing of the plants results in high fiber, lower quality forages. Monitoring stands for the emergence of the flag leaf is important. Shortly after flag leaf emergence the flower head will emerge. Timing of harvest prior to head emergence is the goal. Producers can carefully dissect tillers or feel for the flower head to determine stage of growth.

High amounts of forage dry matter from rye stands present a challenge for rapid dry down. The faster the forage is wilted to optimum fermentation dry matter levels the higher the levels of plant sugars remaining in the plant which results in better fermentation and higher quality forage. By mowing and not conditioning the rye and then putting the forage in as wide a swath as possible producers can take advantage of sunlight to increase rates of dry down. Conditioning is important for drying forages to hay moisture levels but does not benefit haylage storage practices.

Many successful ryelage producers also ted their rye to speed dry down. Most will ted as soon after mowing as the surface of the swath is dry. This is usually followed by a second tedding when the tops of the forage is dry and finally a rake is used when dry matters are close to harvest targets (35 – 38%) to prepare the field for chopping.

Another successful practice is to include the use of inoculants to speed the fermentation process in the ryelage storage structure. Be sure to talk to your supplier to select the proper inoculants for a ryelage crop. Be certain to check inoculant rates and the manufacturer date to ensure high quality products. When filling the inoculant tank do not use chlorinated water. Chlorine in public water systems can negatively affect inoculants survivability. Another factor that has been shown to affect inoculant survival is temperature of the water on the choppers. When tanks are located near engines and/or exposed to sunlight, high water temperatures can reduce viability of the bacteria. Rapid harvest, heavy packing and covering of the pile are additional keys to ensuring high quality forages in bunker silos.

Legume cover crop challenges this spring — Ron Hoover, PSU On—Farm Research Coordinator

The interest in the use of cover crops in Pennsylvania and the northeast continues to grow. While many farmers have experience with fall planted cereals, for use as a cover crop or for grain, fewer have experience with fall—planted legumes. Properly inoculated, and provided the opportunity to grow, they are capable producing a lot of biomass and fixing considerable amounts of nitrogen. In fact, many do not produce much biomass or fix much nitrogen between planting and winter freeze—up. Only after the snow has melted and temperatures are warm enough for spring growth are many legumes able to grow the biomass and fix the nitrogen that caused us to consider growing them in combination with or as a substitute for a cereal or grass cover crop.

Reports from several areas indicate that some stands of legume cover crops this spring are less than ideal. After some digging into the details of these plantings we are finding that the planting dates of these poor—looking stands occurred earlier than recommended. But, one might ask, if we can plant earlier, such as after oat or wheat harvest, we can have more biomass produced going into the winter, can’t we? While more biomass provides more cover and results in the crop having taken up and held onto more nutrients, too much of a good thing can be bad. It appears that too much legume growth when headed into winter results in plants that are less winter hardy and more susceptible to winterkill. But, if the lowest winter temperatures aren’t that low or they occur when there is appreciable snow cover, the crop can be protected and may not be damaged. But can you count on a mild winter every year?

Specifically, problems were seen when planting hairy vetch or Austrian winter pea much earlier than the end of August in southeast or south central PA. In those areas, hairy vetch tends to do best when planted between early and mid September. When moving north toward the central part of PA, the ideal planting date moves back 1 to 2 weeks. Remove another 1 to 2 weeks when looking at legume plantings in the northern tier of PA. Austrian winter pea can also be planted too early, as we witnessed in a Columbia County trial. Plots drilled on August 22 stands did not overwinter well. Plots planted a month later on September 23 look great! What has me even more encouraged about opportunities to use Austrian winter pea after early fall grain harvest is the potential for this species to overwinter even when planted a month (perhaps more?) later than the optimum planting time for hairy vetch. We will continue to look into the later planting potential for this species.

Another source of problem can be the source of legume cover crop seed. Specifically, where was the seed grown? For hairy vetch especially, we are finding that survivability and overall plant density and spring vigor is much better when the seed is from an area where winters are at least as tough as yours. Why? It appears that winterkill—selection is at work. “Tender” genotypes don’t survive and produce seed, resulting in a more “winter hardy” population of seeds. When purchasing these seeds, don’t hesitate to ask where the seed was grown. Source of seed and planting at the appropriate times can go a long way to determining if you will have a success or failure the following spring.

On Farm Internet Access

CENSUS OF AGRICULTURE:
Last month we discussed women farm operators in Pennsylvania. Now let’s look at Internet access on the farm.

The number of Pennsylvania farms reporting Internet access increased from 43% in 2002 to 51% in 2007. For the first time, in 2007, the census also looked at high—speed Internet access. Of those producers accessing the Internet, 57% reported having a high—speed connection.

Nationally, 57% of all farmers have Internet access, up from 50% in 2002. Of those producers accessing the Internet, 58% reported having a high—speed connection.

Looking at Pennsylvania farms with Internet access by value of sales shows that those with less than $50,000 in sales had a rate of 52%, $50,000–$499,999 had 42%, and $500,000 and over had 66%.

Mark Your Calendar

Contributors: County Educators: Mena Hautau (Berks), Del Voight (Lebanon), Jonathan Rotz (Cumberland County), John Rowehl (York County), John Bray (Lebanon County), Jeff Graybill (Lancaster County), Susan Alexander (Jefferson County), Joel Hunter (Crawford county)and Mark Madden (Sullivan). Department of Crop and Soil Sciences: Greg Roth, Sjoerd Duiker, Marvin Hall, Dwight Lingenfelter, Doug Beegle, Ron Hoover. Department of Entomology: John Tooker: Meteorology: Paul Knight.

Editor: Paul H. Craig (Dauphin County)

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