Field Crop News

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

August 5, 2005    Vol. 05:10

IN THIS ISSUE:

Mark Your Calendar

Production

Agents Corner

MARK YOUR CALENDAR

The Eleventh Annual Northeast Buckwheat Field Day comes to the Twin Tiers on August 23. The field day will be near Corning, NY at the Big Flats Plant Materials Center. The Big Flats Plant Materials Center is at 3266-A State Route 352 in Corning. To get there, take Interstate 86/ Route 17 to exit 48 (East Corning/Route 352). Then follow State Route 352 east for 1.5 miles to the center. The entrance is on the left. The program will run from 1:00 to 3:30. Pre-registration is not required, and there is no charge.

More information about the field day is available at http://www.nysaes.cornell.edu/hort/faculty/bjorkman/buck/NL/NL.html or by contacting Thomas Björkman, Associate Professor of Vegetable Crop Physiology, Department of Horticultural Sciences, Cornell University, 630 W. North St., Geneva, NY 14456 Phone: 315-787-2218

PRODUCTION

CARBON SEQUESTRATION AND FARMING

Despite the fact that the U.S. has not ratified the Kyoto Protocol, many other countries have. In a global economy, it becomes very difficult to maintain an isolated position that can have negative economic repercussions. The attitude of the current U.S. government administration seems to be to let the states experiment with different approaches as they see fit. Some states are already taking action, and I participated in a conference organized by the Rendell administration brainstorming about Pennsylvania's role in the area of global warming. At the same time, many multinational companies now recognize global warming as a reality and, instead of trying to negate their responsibility, they try to turn it into a business opportunity. The bottom line is that action regarding greenhouse gas emissions is happening in many countries is already coming to the U.S. as well.

What does this all mean for Pennsylvania agriculture? There are three greenhouse gases that are of particular importance for us: carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O). These gasses act as the glass of a greenhouse: they let short-wave radiation from the sun in, but do not let long-wave radiation from the earth out. Thus they insulate the earth. With increasing concentrations of these gasses in the earth's atmosphere, it is likely that the average temperature of the atmosphere increases. This can have negative consequences, such as rising sea level, warmer summers and winters, more volatile weather, droughts etc. The rising concentration of greenhouse gases is largely due to human activities such as combustion of fossil fuel and land use changes such as deforestation. Hence the Kyoto protocol calls for limiting these emissions, or compensating for them.

Compensating for emissions is the principle behind carbon sequestration: the idea is that, through photosynthesis, CO2 is absorbed from the atmosphere, incorporated in plant materials, and part of that is then stored, for example in the form of humus in soil. Humus has been shown to have a long residence time, i.e. it stays in the soil for a long time. This in contrast to plant residues, most of which are decomposed in one year. Thus all practices that increase organic matter content in soil lead to carbon sequestration, which helps slow the increase of CO2 concentrations in the atmosphere. At the same time, however, these practices should not lead to increases in N2O or CH4, because that could negate the benefits of carbon sequestration for global warming.

A recently published review of 67 long-term trials revealed that a conversion from conventional tillage (moldboard plow) to no-till sequestered 640 lbs C/acre/year for a period of approximately 15-20 years. After that a new soil organic matter equilibrium was reached and no additional carbon sequestered. In wheat-fallow rotations in the west of the U.S. no carbon sequestration was observed by a change in tilllage. The difference in carbon sequestration between reduced tillage systems such as chisel plowing and disking and no-till is frequently not significant, and sometimes there is not even a difference in carbon content between no-till and moldboard plowing. The latter was has been observed in trials in eastern Canada, for example. In those trials a low surface soil organic matter content in conventionally tilled compared with no-till soils was offset by a high soil organic matter content at the bottom of the plow layer. These results were attributed to the depth of plowing (8-12"), cool soil temperatures, and poor drainage conditions in eastern Canada.

More carbon is usually sequestered with no-till than conventional tillage.

More diverse crop rotations (with the exception of a change from continuous corn to corn-soybean rotations) also help sequester carbon, but at a slower rate than a change in tillage. An average rate of 225 lbs C/acre/yr was observed. However, the increase in organic matter content with more complex rotations was observed to last much longer (40-60 yrs) than that due to a change in tillage.

Nitrogen fertilization has also been found to increase carbon sequestration primarily because of the higher plant productivity which leads to greater return of plant residues to the soil. There are indications that there is no increase in organic matter content if crop residue is not returned to the soil.

Manure applications have also been observed to increase carbon sequestration. However, the increases seem minimal if liquid manure is used.

Results of research suggest that there is usually no increase in N2O emissions from soil by a change in tillage. Exceptions are mostly on poorly drained soils, where a change from tillage to no-tillage leads to even more frequent anaerobic soil conditions and higher denitrification (and therefore N2O emissions). Another exception is where fall-plowing is used: this can lead to substantially higher N2O emissions than with no-tillage or spring plowing because of the fast decomposition of plant residue and accompanying release of nitrogen.

A change in crop rotations can affect the N2O emissions from soil: this is primarily because of the close relationship between nitrogen applications and N2O emissions. Thus a crop such as corn that receives large N-fertilizer applications can be expected to have higher N2O emissions than a crop such as soybeans or alfalfa, or, for that matter, small grains. Rotating corn with alfalfa is a practice that also reduces N2O emissions compared with continuous corn.

Most agricultural soils (if not too poorly drained) act as moderate sinks of methane (CH4). This methane absorption is dwarfed, however, by that released by farm animals. It is estimated that more than 700 acres are need to compensate for the methane released by one dairy cow.

Thus we see there are opportunities to sequester carbon in soils by using certain best management practices. Without a viable carbon market in the U.S. these 'carbon credits' are not worth much yet, but different days may be not too far ahead.

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

WHEAT CROP REVIEW

Wheat fared better than expected, just like barley, and grain quality seemed to be very good. Many reports of 80 bu/A and higher with excellent grain quality were reported. Quality likely declined in fields where harvesting was delayed due to the wet weather and some reported saprophytic black fungi moved on to the crop prior to harvest. Our variety test data are still being finalized, but initial indications were that our yields and quality were very good. One of the challenges we are finding is the variation in variety performance in wheat across environments. In relatively dry years like this, when disease resistance plays a relatively minor role in yield, variety rankings will likely be somewhat different than in wetter years. This makes variety testing, development and selection in our region a challenge. It pays to look at multiyear testing data if possible. We are finalizing our data processing. Preliminary soft wheat data will be posted next week on the small grains website at http://smallgrains.psu.edu/.

Greg Roth, gwr@psu.edu
Grain Crop Management, Crop and Soil Sciences

BARLEY UPDATE

Our barley this year yielded more than I expected, and averaged over 100 bushels per acre in our variety tests. Our test at Landisville was a bit lower, but did surprisingly well too. Growers who had similar grain and good straw yields and prices were pleased with the crop. The take home message from this year was that if barley stays standing and disease pressure is low, yields can be very good. The variety test data will be posted next week on the small grains website at http://smallgrains.psu.edu/. This seemed to be a good year for Pennco and its potential upcoming replacement lines PA9550-157 and PA9550-151, which had similar yields and slightly higher test weight. They both have excellent winterhardiness, good spring vigor and good tolerance to drought stress.

Our only hulless barley, Doyce seemed to have a good year, averaging on a bushel basis about 70% of the best hulled lines, or about 80% yields on a dry matter basis (hulless barley has a 56-60 lb test weight). This would suggest that producers would need approximately 30% higher prices for hulless barley bushels than for hulled barley to compensate for the lower yields. At current barley prices of $1.64/bushel, an equivalent price for hulless would be $2.34/bushel. Given that hulless barley could be a substitute for corn that is currently priced around $2.60/bushel, it seems there is some opportunity for this crop. We are evaluating newer lines that may have higher production potential than Doyce, so that might improve the prospects for this crop even more. I am working on identifying seed sources for those who might be interested in trying this crop this fall.

Greg Roth, gwr@psu.edu
Grain Crop Management, Crop and Soil Sciences

SOYBEAN APPROACHING CRITICAL YIELD STAGES

August stress can limit soybean pod and seed development.

Soybeans around the state responded well to the mid-July precipitation and are now reaching the critical full pod (R4) and beginning seed (R5) stages. The R4 stage is characterized by pods at least ¾ inch long on one of the four uppermost nodes with a completely developed leaf. At (R5) seeds at least 1/8th inch long will be visible in pods at one of the four uppermost nodes. These stages are critical in yield development in soybeans, since pods and seeds in pods can abort under stress and flowering and potential pod development becomes complete by about R5.5 or mid-late August.

Stress in the form of drought, heat, disease, or insect damage can take its toll on pod and seed development during this period. So conditions during the next few weeks will be critical in the development of yield potential in our soybean crop. This is also why monitoring for diseases and soybean aphids during this stage is most critical while the effects of these pests decline as we advance in maturity through late R5.

Greg Roth, gwr@psu.edu
Grain Crop Management, Crop and Soil Sciences

LATE SEASON CORN ASSESSMENT AND MANAGEMENT

Much of our corn is experiencing a typical Pennsylvania summer with periodic episodes of drought stress. Our mid July precipitation gave the crop a critical boost through late vegetative and early reproductive stages but I am sensing that we may be starting another widespread dry period for the next several weeks. Since corn can use up to 0.25 inches of water per day during this period, it is difficult for our precipitation to keep up with demand from the plant. Effects of drought during this period will be kernel abortion on the ear tips and reduced kernel fill. We should start making some early yield assessments soon to assist with harvest planning. A lot of corn I've seen seems a bit on the short side, which may lead to lower silage yields than we saw last year. On the positive side, shorter corn due to drought stress often results in high fiber digestibility in our silage.

During the humid weather in late July, I began to notice several of the common corn diseases like gray leaf spot and northern corn leaf spot moving up in the canopy in some fields. I'm also going to be on the lookout for the irregular cigar shaped lesions of northern corn leaf blight, which has been an increased problem during the past few years.

Northern corn leaf blight symptoms.

Assessment of the disease reaction of hybrids is a critical management decision that is often overlooked with all of the attention on biotech traits. Dry weather now may keep some of the foliar diseases at bay. Last winter, though, I received a surprising number of comments from producers having significant problems with foliar diseases. Now is also a good time to make observations on N deficiency symptoms and root lodging which can provide some feedback on fertility and insect management tactics.

Another key management tactic now should be preparing for silage harvest. With the large amount of early planted acres, silage harvest could be compressed this year, which could tax our resources to get the crop harvested in a timely fashion. It's unclear whether harvest will be early or not. In some areas, I think the early season cold weather and drought stress may have delayed silking and crop development to offset the early planting effects. Several of our corn studies silked around the third week of July which seems about average for early planted corn. Normally, silage harvest starts about 45 days after silking which would put us into early September. The bottom line will be to monitor silage maturity beginning in mid-August and make harvesting plans based on those assessments.

Greg Roth, gwr@psu.edu
Grain Crop Management, Crop and Soil Sciences

Agents Corner

Capital

Despite having numerous days with temperatures in the nineties, corn and soybeans have excellent growth. What a difference from what we were seeing a month ago before we were blessed with several good rains that occurred weekly in July. Most corn is in the milk stage (R3). The more advanced soybeans are at growth stage R5 (beginning seed) but more are in late R3 (beginning pod) to mid R4 (full pod). In a field that I monitor weekly for rust, the soybean aphid population is on the rise but not yet at threshold. Young aphids (nymphs) that are whiter in color are becoming more noticeable. Some reports have been made of fields above threshold. Double crop soybeans following wheat are at the unifoliate to first trifoliate stage.

John Rowehl, jrowehl@psu.edu
Cumberland County

Northwest

Greetings from the great Northwest. What a difference a month (and some rain) can make! Like many parts of the state, much of our area had been without significant rainfall for four to six weeks, which can roughly be translated into a moisture deficit of four to six inches of rainfall. Much of our corn was rolling pretty bad during the day but still managing to come out of it overnight. Many folks were of the opinion that another week or so of hot and dry would have really hurt the corn. Soybeans lagged behind corn in development and seemed to take forever to begin closing canopy. Third cutting wasn't growing very well, especially the grasses. Small grains were one of the better survivors and filled and matured nicely for the most part. Some early planted oats looked really nice, but I'm concerned about blasting with the heat we had. However, our drought finally broke with the onset of the early and numerous named storms from the south this year. Some of the badly needed rains and humidity did present some scab in wheat at harvest, but the crop came off pretty well overall. Most areas made up their four to six inch rainfall deficits in a series of significant showers over the area the second half of July...just in time for corn pollination.

Once the moisture came and coupled up with our better than average heat units, corn really took off. I have photographic evidence of over two feet of growth in a single week. Much of our corn now has better than average height and is in really good condition. Pollination is well under way now or over on some early corn. Separation between early and late maturity corn was quite apparent this year with plenty of heat units and shorter season corn tasseling soon after the rains and longer season hybrids continuing to add height as tasseling progress lagged. Our less than 100 days corn is in milk while our 100 plus days corn is in blister. Corn is looking excellent now, and there's a lot of season left. Grain and silage prospects both look very good at this point. We'll need to be watchful for a possible earlier harvest on silage. Soybeans finally came around and started to look like something. Most of the soybeans have closed canopy now and some of the most developed have pods with small beans. Producers are watching their soybeans more carefully and discovering (or rediscovering) some mite damage (which has lessened with the showers), some isolated thrip damage, and some pretty good examples of Cercospora Blight and Brown Spot along with a little other miscellaneous foliar infection. It's probably still a little too early to assess the soybean potential, but the outlook has dramatically improved in the last week or so. There are some nice looking soybeans that are approaching R4 stage. Third cutting grass was coming off all around the area the last week of July. I really think most producers were about to give up on third cutting grass prospects, but the rains came and the grass suddenly came to life. Preliminary yields suggest modest production but another ton or so (dry matter) of good forage will help. Third cutting of legume and mixed hay will be sure to follow, probably getting well underway this week.

It's been a unique season with a dry spring and a hot and dry early summer. Now we've got some badly needed moisture and prospects are suddenly looking pretty good. We'll just have to see what kind of month August turns out to be for filling grain. At this point, I'd say we may be on course for an early and perhaps above average harvest. Of course, production between now and then and harvest itself will depend a lot on the weather. We're getting more hopeful all the time.

Good growing to all!

Joel M. Hunter, CCA,, jmh7@psu.edu
Crawford County
Northwest Dairy Team

Southeast

Hot and dry in the southeast! Making hay, harvesting oats and hauling manure on wheat stubble or hay stands have been the activities the past week or so. The east side of Berks County has received more frequent rainfall and crop development is better. However, with the current heat wave, there is a need for moisture again.

Full season soybeans are in R3 and beyond. There have been reports of a few producers treating for soybean rust, although it seems economically unwarranted. Grasshoppers, aphids and Japanese beetles are a bigger risk right now.

Hay producers are invited to a Southeast Pennsylvania Crops Conference: Forage Equipment Twilight Meeting on September 8, 6-8 p.m. at the Paul Reidenhour Farm, Hamburg. The program emphasizes equipment to speed drying. Please register with Penn State Extension-Montgomery County 610-489-4315 by September 1.

Mena Hautau, CCA, mmh10@psu.edu
Berks County

Southwest

Conditions in SW PA have become very dry, with the exception of a few pockets that have been getting some rains. July precipitation was as low as 1.5 inches. The early planted corn is faring the best, getting some key rains during pollination. Silage harvest in these fields should begin by the end of the month. Later planted corn fields, especially those planted into harvested 1st cutting alfalfa, are in desperate need of rain.

Soybeans are looking good, best fields are over 3 feet and maturity stage R4-R5. Foliar diseases turning up are Septoria Brown Spot and some Downy Mildew. A few producers are planning to spray fungicides and hopefully get a yield boost. Spider Mite damage is visible on field margins and populations are on the rise with the current weather. Soybean Aphid populations are also on the rise, continued scouting will be necessary with these two pests.

The sunny weather is allowing farmers to make plenty of silage and dry hay. Third cutting turned out to yield more than second. Pasture growth has all but stopped with producers supplementing with round bales. With each cutting this year being less than average yield and having to supplement pastures, forage supplies could be on the tight side this winter.

Kevin Fry, ksf107@psu.edu
Armstrong County