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Time to start topdressing wheat

There are few crop inputs that deliver as much return on investment as nitrogen fertilizer. It takes approximately two pounds of nitrogen, costing approximately $1.00, to produce one bushel of grain worth about $5.00. Of course, nitrogen is not the only yield determining factor in a wheat crop. Also, the law of diminishing marginal returns eventually kicks in, but nitrogen fertilizer is still one of the safest bets in the house.

Top dress nitrogen fertilizer is especially important because it is applied and utilized at a time when the plant is transitioning from vegetative to reproductive growth. Several things, including the number of potential grain sites, are determined just prior to jointing and it is imperative that the plant has the fuel it needs to complete these tasks. Jointing also marks the beginning of rapid nitrogen uptake by the plant which is used to build new leaves, stem, and the developing grain head. The nitrogen stored in these plant parts will be used to fill the grain later in the season, and the plant is dependent on this stored nitrogen to complete grain fill.

In the bullet points below, I will hit the major points regarding top dress nitrogen for wheat.  I have also posted three slide presentations with audio regarding topdressing wheat at my YouTube channel available by clicking here or by searching YouTube for OSU Small Grains. 

When to apply

  • In order to have full benefit, nitrogen must be in the rooting zone by the time wheat is jointing. Jointing occurs around the end of February in southern OK and around the second week of March in northern OK.
  • Moisture is required to move nitrogen into the rooting zone. Since precipitation is usually very limited in January and February in Oklahoma we need the nitrogen out on the field when the precipitation arrives. This, along with the fact that we have 5.5 million acres to cover, means that we need to get started in January to get everything taken care of in a timely fashion.
  • If you are using the Sensor Based Nitrogen Recommendation system your yield predictions and nitrogen recommendations generally become more accurate as the season progresses; however, growers wishing to hedge their nitrogen bet could apply a partial top dress in January or early February and supplement with a second top dress just prior to jointing if SBNR recommendations call for additional nitrogen.
  • Do not apply nitrogen to frozen ground. Nitrogen will move with water. If melting snow or frozen rain is moving to the ditch, so will nitrogen applied to the soil surface.
  • Consider splitting or delaying top dress nitrogen applications to sandy soils until closer to jointing, as leaching can occur.

How much to apply

  • On average it takes about 2 lbs/ac of N for every bushel of wheat yield. In addition, dual-purpose wheat requires 30 lbs/ac of N for every 100 lbs/ac of beef removed. You can subtract your soil test NO3-N from these total requirements.
  • It is okay to adjust topdress N plans based on your current yield potential. When you submitted your soil test, you might have stated a 50 bu/ac yield goal which would require 100 lbs/ac of nitrogen; however, it is important to take a hard look and determine if this yield goal is still realistic based on your current crop status. I am not suggesting to adjust based on what you think the weather might do, but it is okay to take inventory and adjust your topdress N up or down based on current field conditions.
  • Don’t have an N-rich strip? It would be a lot cooler if you did. An N-rich strip would take the guess work out of adjusting your topdress N up or down based on your current crop conditions. Your county extension educator can provide more information on N-rich strips and you can find more information on the web at www.npk.okstate.edu

What source to use

  • The plant does not care about nitrogen source. A pound of nitrogen is a pound of nitrogen. Focus on getting the correct amount applied at the correct time, and choose your product based on price and application uniformity.
  • Use a source that can be applied uniformly. In my experience, spinner trucks or buggies are generally the least uniform. Air trucks or streamers are the most uniform.
  • Streamer nozzles almost eliminate leaf burn from UAN; however, leaf burn is generally not an issue until temperatures warm and/or you are applying fairly large amounts of UAN. Stream nozzles are also not affected much by wind and deliver a uniform pattern in a variety of conditions. There are also some studies that indicate banding of UAN through the use of stream nozzles will reduce nitrogen immobilization on crop residue. All in all, I am a big fan of streamer nozzles. You cannot, however, tank mix herbicides when using streamer nozzles.
    Streamer nozzles provide uniform application of UAN in a wide variety of environmental conditions.

    Streamer nozzles provide uniform application of UAN in a wide variety of environmental conditions.

    Poor nitrogen application can result in a streaked field. Some of the areas in this field were over fertilized while some were under fertilized resulting in wasted nitrogen and less than optimal crop yield.

    Poor nitrogen application can result in a streaked field. Some of the areas in this field were over fertilized while some were under fertilized resulting in wasted nitrogen and less than optimal crop yield.

Winter grain mites in northcentral OK

Jeff Bedwell forwarded reports of winter grain mites in Major and Alfalfa counties over the past week. This does not appear to be a widespread problem, but growers should check wheat fields to see if winter grain mites are present. We had a lot of issues with winter grain mites and brown wheat mites in Oklahoma last year. Unfortunately, many of these fields were not diagnosed until the damage was severe and visible from a distance. In this case, a rescue treatment was still effective at controlling the pest, but some yield loss had already occurred thus reducing the return on pesticide investment.

Winter grain mites are small (about 1 mm long) with black bodies and orange-red legs. Winter grain mites complete two generations per year and the adults can live for up to 40 days. The generation we are dealing with now resulted from oversummering eggs laid last spring. The second generation peaks in March/April and results from eggs laid in January/February.

Image

Winter grain mites on wheat near Blair, Oklahoma.

 

Scouting
Winter grain mites are not a problem you will notice in a timely fashion while standing up. You will need to get close to the soil surface and move residue to find these pests. Winter grain mites are light sensitive and prefer calm air to windy conditions; therefore, scouting early in the morning, late in the evening, or on cloudy days generally works best. Be sure to look under residue in no-till fields and under clumps of soil in conventional-till fields.

Scouting for winter grain mites requires getting close to the soil surface and moving residue to disturb mites.

Scouting for winter grain mites requires getting close to the soil surface and moving residue to disturb mites.

Injury

Winter grain mites feed by piercing plant cells in the leaf, which results in “stippling”.  As injury continues, the leaves take on a characteristic grayish or silverish cast.  Winter grain mites are more likely to cause injury in wheat if it is already stressed due to lack of moisture or nutrients. Also be advised that freeze injury can easily be confused for winter grain mite injury.

Wheat damaged by winter grain mite often has a silver or grayish appearance from a distance

Wheat damaged by winter grain mite often has a silver or bronzed appearance from a distance

When to spray
There are no established thresholds for winter grain mite. Healthy, well-fertilized wheat plants can generally outgrow injury, so it takes large numbers to justify control. If there is injury present AND large numbers of mites (~10 per plant) present in grain only wheat this time of year, you might consider control. If the wheat is to be grazed, I would simply monitor the situation in most cases and only spray if injury became severe.

What to spray
Malathion is the only product labeled for wheat in Oklahoma that has winter grain mite on the label. There are many additional products, such as some of the pyrethroids and chlorpyrifos, that are effective at controlling winter grain mite, but they don’t have a specific label for them. These products can be applied under 2ee regulations; however since this pest is not specifically labeled, the user assumes all responsibility for the application of the product.  It is also important to read and follow label directions regarding grazing restrictions for these and all pesticides.  Consult OSU Current Report 7194 Management of insect and mite pests in small grains for a more complete listing of available pesticides.

Greenbugs reported in northwestern Oklahoma

By Tom Royer, OSU Extension Entomologist

Crop consultants have reported greenbugs in a few northwestern Oklahoma wheat fields. The hit or miss nature of greenbugs and other aphid pests in wheat fields can make scouting challenging. Fortunately, there is an online tool called the Cereal Aphid Decision Support Tool that simplifies scouting for greenbugs and also considers the effects of natural predators.

Greenbugs on wheat

Greenbugs on wheat

Start by going to the Cereal Aphids Decision Support Tool on your computer http://entoplp.okstate.edu/gbweb/index3.htm and selecting the Greenbug Calculator.

By answering a few simple questions, you can determine an economic threshold for controlling greenbugs.  This threshold is based on the estimated cost of treating the field and the estimated price of wheat.  Once a threshold is calculated, you can print a Glance ‘n Go scouting form, take it to a field and record your sampling results.  The form will help you to decide if the field needs to be treatment for greenbugs.  There are several things that make Glance ‘n Go a good way to make such a decision. You only have to “Glance” at a tiller to see if it has greenbugs (no counting greenbug numbers).  You can make a decision to treat “on the Go” because you stop sampling once a decision is reached (no set number of samples).  Finally, you can account for the activity of the greenbug’s most important natural enemy, Lysiphlebus testaceipes.

When scouting with the Glance ‘n Go system, keep a running count of tillers that have aphid mummies and a running count of tillers that are infested with one or more greenbugs.  After each set of 5 stops, the Glance ‘n Go form directs you to look at your total number of infested tillers and tillers with mummies.  If there is enough parasitoid (mummy) activity, you will be directed to stop sampling and DON’T TREAT, even if you have exceeded the treatment threshold for greenbugs!  Why? Because research showed that at that level of parasitism, almost all of the healthy-looking greenbugs have been “sentenced to death” and will be ghosts within 3-5 days.  If they have received their “sentence” you can save the cost of an unnecessary insecticide application.

Natural predators can keep greenbug infestations below economic thresholds

Natural predators can keep greenbug infestations below economic thresholds

Treatment thresholds will probably fall around 2-4 greenbugs per tiller, but make sure you are using the Fall (Sept.-December) form, not the spring form.  If a field needs to be treated, check with Current Report CR-7194, “Management of Insect and Mite Pests in Small Grains”.  If you treat for greenbugs and have a failure, please contact our Department and we will investigate further to determine if insecticide resistance might be an issue. Dr. Ed Bynum, Extension Entomologist from Amarillo, reported finding some greenbug populations in 2013 that were shown to be resistant to chlorpyrifos, the active ingredient in Lorsban 4E, and other generic products (Govern 4E, Hatchet, Nufos, Vulcan, Warhawk, Whirlwind).   The bottom line:  he tested some suspect greenbug populations using a diagnostic test that he developed for testing greenbugs in sorghum in the 1990’s, and found that they were resistant to chlorpyrifos at labeled rates.

Wheat protein report – 2014

This blog post contains information from OSU Current Report 2135 Protein Content of Winter Wheat Varieties in Oklahoma. A complete pdf version of the report with a brief explanation of sampling procedures can be found at www.wheat.okstate.edu.

The grass always seems to be greener on the other side when it comes to wheat protein. In a low protein year, everyone is scrambling to find higher protein wheat to blend. In a high protein year, such as this one, the same low protein wheat that was considered marginally acceptable the year before might command a slight premium. While wheat protein is important to end users, wheat protein is just one of many attributes which determine end-use quality and marketability of winter wheat. In fact, some millers and bakers would argue that functionality of wheat protein is more important than the quantity of protein. While varietal differences commonly exist, differences in wheat protein among environments are generally much larger than differences among varieties. Factors such as nitrogen fertility and drought stress, for example, can sharply impact final protein content of the grain, and most producers are better served focusing on good agronomic practices than slight genetic differences in wheat protein content.

To reflect environmental impacts on wheat grain protein content, 2014 wheat variety test data are reported by variety and location in Table 1. The 18.5% average wheat grain protein for the Thomas location is a good example of how fertility and environment can impact protein content. Soil tests at the time of sowing revealed 141 lb/acre of residual nitrogen available, which should be enough to produce a 70 bu/acre wheat crop. Due to extreme drought, however, average grain yield at Thomas was 13 bu/acre. Under these circumstances, wheat plants were able to pull large amounts of nitrogen from the soil and move this nitrogen to the developing grain. Grain size was reduced and grains were shriveled due to drought, thus resulting in abnormally high wheat protein. A similar situation was reported for Altus in 2013.

In Table 2 we reported the wheat grain protein content as a deviation from location mean for each variety, as this provides easier comparison of wheat grain protein among varieties across locations. Billings, for example, is a variety with solidly positive deviation from location means, indicating it has a tendency for above-average grain protein content. Iba, on the other hand, has negative deviations from location means, indicating a tendency for lower than average grain protein content. Adequate nitrogen fertility as recommended by a recent soil test or sensor-based nitrogen management program can help ensure that varieties such as Iba produce grain protein within the acceptable range for end-use customers. Iba is also a prime example of how protein data can sometimes be misused, as the functionality of the protein in Iba is above average, which can offset lower absolute grain protein content.

How to make $100,000 in a day

No, this blog post is not about a get rich quick scheme, but there is a way for the average wheat farmer in the southern Great Plains to add $50,000 to $100,000 to the bottom line in a single day. Most soil tests I have pulled this summer have shown 50 to 90 lb/ac of NO3-N in the top 18 inches of soil. Ninety pounds of N equates to about $45 of N fertilizer, and this knowledge could save a 2,500 acre wheat farmer in excess of $100,000 in fertilizer cost. Soil testing is laborious, but the potential economic returns for spending a day or two soil sampling are outstanding.

There is still time to soil sample. Soil samples only take a few days to process once they are in the OSU lab. It is not unusual for transit time to the lab to the slowest part of the process, so if you need a fast turnaround a trip to drop samples in the Ag Hall basement in Stillwater will help (plus you have probably been wanting cheese fries). If you have already applied pre-plant fertilizer or sown wheat, there is still time to assess soil N availability and uptake via the N-Rich Strip. In its simplest form, the N-rich strip is an area where N is not limiting. Either by visual assessment or with the assistance of an optical sensor, you can use the N-rich strip to determine your top dress N requirement, but you must create the N-rich strip this fall.

Soil testing is not always easy, but it is time well spent. My high school shop teacher would have labeled me a "Primitive Pete" for this photo.

Soil testing is not always easy, but it is time well spent. My high school shop teacher would have labeled me a “Primitive Pete” for this photo.

The bottom line is that a day of soil testing or putting out N-rich strips is well worth your time investment. On another note, how would you like to make money and improve your health at the same time? I have a multi-level marketing opportunity that I can get you in on the ground floor, but don’t tell anyone else. I can only make this deal for you and only today. There will be a small “buy in” fee that you will need to pay cash up front, though.

Partial funding for the research included in this blog post was provided by USDA Project No.2012-02355 through the National Institute for Food and Agriculture’s Agriculture and Food Research Initiative, Regional Approaches for Adaptation to and Mitigation of Climate Variability and Change

Planting wheat in hot soils

Kickoff of the college football season and the start of wheat planting are Labor Day traditions in the southern Great Plains. Many producers are waiting to see if rain forecasted for this weekend materializes, but it is likely that forage-based wheat farmers will start sowing wheat next week whether it rains or not. This means sowing wheat into hot soil conditions which can cause wheat germination and emergence issues. Given the potential problems, there are a few questions producers should ask themselves prior to planting into soil temperatures >90F.

coleoptile length

If the wheat coleoptile does not break the soil surface, the germinating wheat plant will not survive.

Will you have to plant deep to reach moisture? That first structure protruding from a germinating wheat seed is actually not a leaf. It is the coleoptile. The wheat coleoptile is a rigid structure whose sole purpose is to “punch through” the soil surface so that the first true leaf emerges above the soil surface. If this does not happen, the first true leaf will try to extend below the soil surface, turn yellow, and take on an accordion-like appearance (picture above). Modern semi-dwarf wheat varieties have shorter coleoptiles than older, tall wheat varieties and coleoptile length is shortened even further by hot soil conditions. So it is important to plant a variety with a longer coleoptile length (e.g. Garrison or Doans) if planting deeply into hot soils. A rating of coleoptile lengths for wheat varieties can be found in OSU Fact Sheet 2141 OSU Wheat Variety Comparison Chart available at www.wheat.okstate.edu or at the direct link to the publication here.

Is the variety high temperature germination sensitive? High temperature germination sensitivity is a fancy way of saying that some wheat varieties simply don’t germinate well in hot soil conditions (e.g. 2174, Overley). The extent of the sensitivity varies by year, so Overley might germinate fine in 95F soils one year and produce a 10% stand in the same soil conditions the next. When sowing early, it is best to plant varieties that do not have high temperature germination sensitivity (e.g. Duster, Gallagher, or Armour). Soil conditions generally cool due to lower ambient temperatures or cooling rains by about September 20; however our summer temperatures seem to be arriving late this year, so it is best to know the level of germination sensitivity in the variety you are planting. A rating of high temperature germination sensitivity for wheat varieties can be found in the variety comparison chart linked above. A more detailed explanation of the phenomenon can be found in OSU Fact Sheet PSS 2256 Factors affecting wheat germination and stand establishment in hot soils (available by clicking here).

Partial funding for the research included in this blog post was provided by USDA Project No.2012-02355 through the National Institute for Food and Agriculture’s Agriculture and Food Research Initiative, Regional Approaches for Adaptation to and Mitigation of Climate Variability and Change

2014 Wheat Crop Overview

This blog post is an excerpt from the 2014 OSU Small Grains Variety Performance Tests report, which is available at http://www.wheat.okstate.edu or by clicking here.

At the time of writing this post, 2014 Oklahoma wheat production is estimated to be approximately 51 million bushels, which is roughly half of 2013 production (Table 1). Oklahoma has not seen wheat production this low since the 43 million bushel crop of 1957, and with any luck, production will not be this low again for at least another 60 years.

 

Table 1. Oklahoma wheat production for 2013 and 2014 as estimated by OK NASS, July 2014
2013 2014
Harvested Acres 3.4 million 3.0 million
Yield (bu/ac) 31 17
Total bushels 105 million 51 million

 

The 2013-2014 wheat production season had a good start in central Oklahoma. Topsoil moisture was short in September, but October rains resulted in favorable conditions for wheat emergence and establishment. In addition, many areas had a fair amount of stored soil moisture from the summer of 2013. This stored soil moisture allowed sites such as Chickasha and Lahoma to produce 43 and 47 bu/ac average wheat yield on less than eight inches of rainfall during the growing season. Stored soil moisture also contributed to adequate forage production at grazed sites such as Marshall Dual-Purpose, but production of a forage crop did not leave behind enough moisture to fuel much of a grain crop.

 

The multi-year drought never released its stranglehold on western Oklahoma during the 2013-2014 wheat production season. Small rains here or there allowed most producers to obtain an acceptable stand of wheat, but moisture was never sufficient to spur tillering or leaf area development. Early winter snowfall made for a few bright spots for forage production in southwestern Oklahoma, but this moisture was quickly utilized by growing wheat plants and dry conditions soon returned. As a result, many fields in southwestern and western Oklahoma were abandoned and not taken to harvest.

This photo of a wheat field near Altus, Oklahoma in April 2014 shows the level of devastation from the extreme, multi-year drought. Most wheat fields in this region were abandoned due to drought.

This photo of a wheat field near Altus, Oklahoma in April 2014 shows the level of devastation from the extreme, multi-year drought. Most wheat fields in this region were abandoned due to drought.

 

Thin wheat stands left some fields vulnerable to blowing sand and wind erosion

Thin wheat stands left some fields vulnerable to blowing sand and wind erosion

The winter of 2013-2014 wasn’t just dry; it was cold too. Young, drought-stressed wheat plants had difficulty dealing with the cold, windy conditions, and winterkill was common in late-sown wheat. Winterkill was also common in grazed wheat that was stressed by heavy grazing pressure and inadequate soil moisture. Considerable winterkill was also present in no-till wheat without adequate seed to soil contact in northwestern Oklahoma. The inadequate seed to soil contact was generally the result of heavy residue from the previous year’s wheat crop.

Winterkill was common in northwestern Oklahoma, with the greatest injury occurring in no-till and/or grazed wheat fields.

Winterkill was common in northwestern Oklahoma, with the greatest injury occurring in no-till and/or grazed wheat fields.

Closer inspection of some no-till fields with winterkill revealed shallow seed placement due to heavy and/or unevenly spread residue from the 2103 wheat crop.

Closer inspection of some no-till fields with winterkill revealed shallow seed placement due to heavy and/or unevenly spread residue from the 2103 wheat crop.

 

While the wheat crop did not appear to be on its way to bumper production, most producers hoped for a turnaround similar to 2013 and topdressed in late winter. Unlike the spring of 2013, however, the rains never came and much of this topdress N applied did not make it into the soil until the crop was at boot stage or later.

 

The cold winter delayed the onset of first hollow stem by about five days as compared to 2013 and 25 days as compared to 2012. Despite a slow start to the spring, wheat in southern Oklahoma was near heading when a hard freeze occurred the morning of April 15, 2014. As expected, drought stressed wheat in advanced stages in southwestern Oklahoma suffered severe freeze damage; however, injury from the 2014 spring freeze did not always follow the “rule of thumb” guidelines used by agronomists. Many areas that received small amounts of rain just prior to the freeze seemed to escape widespread injury, regardless of growth stage. In southcentral Oklahoma, injury seemed to be most severe on later maturing varieties that were approximately Feekes GS 7 to booting, while earlier-maturing varieties that were just starting to head escaped freeze injury. Wheat that was barely past two nodes in northern Oklahoma suffered severe injury, while more advanced wheat in central Oklahoma endured similar temperatures with minimal injury.

 

There were relatively few insect or disease issues to deal with during the 2013-2014 wheat production season. Winter grain mite and/or brown wheat mite infestations proved to be too much for some drought stressed wheat fields in northcentral and northwestern Oklahoma. Some fields already devastated by the drought were left unsprayed, while others still showing some sign of yield potential were treated.

 

Injury, such as the bronzed areas in the picture above, was the result of brown wheat mite and/or winter grain mite infestations in late winter.

Injury, such as the bronzed areas in the picture above, was the result of brown wheat mite and/or winter grain mite infestations in late winter.

 

Other than a rare siting of a single leaf rust pustule, there was no foliar disease in Oklahoma in 2014. The lack of foliar disease is evidenced by the lack of response to foliar fungicides at either Chickasha or Lahoma. These two sites provided a rare opportunity in 2014 to observe yield impacts of foliar fungicides in the absence of disease, as most years we report at least light or negligible foliar disease at these sites. While foliar disease was not an issue in 2014, wheat streak mosaic virus was an issue for many producers. This disease has historically been most prevalent in northwestern Oklahoma and the Panhandle. Wheat streak mosaic virus was confirmed in several fields downstate this year, however, and it is likely that some fields affected by wheat streak mosaic virus were not identified as such because it is sometimes difficult to distinguish wheat streak mosaic virus symptoms from those of severe drought stress. The wheat variety testing program was not immune from this disease, and we lost our Kildare location to wheat streak mosaic virus.

 

Warmer temperatures in May hastened crop maturity and the Oklahoma wheat harvest began near Frederick on May 22, 2014. By the first week of June, harvest was in full swing, only to be delayed by rain shortly thereafter. Harvest resumed across most of the state by June 13 and was mostly completed by June 30. The exceptions being some waterlogged areas in northern Oklahoma. The Cherokee Mesonet site, for example, reported 5.1 inches of rainfall from October 1, 2013 to May 31, 2014, but the same site received 10 inches of rain from June 1 to June 30, 2014.

Harvest underway

The 2014 Oklahoma wheat harvest is underway and results from the Walters and Thomas wheat variety trials are now posted at http://www.wheat.okstate.edu. Depending on field operations, I usually get variety trial results posted on the web within a day or two of harvest.  The best way to learn when results are posted are to follow me on Twitter @OSU_smallgrains or subscribe to our Extension news list serve (send me an email at jeff.edwards@okstate.edu to be added to the listserv).

I have posted a few pics from our harvest operations below.

 

Wheat checkoff dollars make the Oklahoma Wheat Variety Testing program possible. We appreciate the support of our Oklahoma farmers!

Wheat checkoff dollars make the Oklahoma Wheat Variety Testing program possible. We appreciate the support of our Oklahoma farmers!

Harvest at Walters, OK. Photo courtesy Todd Johnson, OSU Ag. Comm. Services.

Harvest at Walters, OK. Photo courtesy Todd Johnson, OSU Ag. Comm. Services.

Changing tires on the side of I-35 is never fun. We blew two more on the way to Thomas the next day and damaged the trailer. Big shout out to Eley's service center in Watonga and Watonga  Machine and Steel for getting us back on the road. Don't get me started on the lack of American made trailer tires!

Changing tires on the side of I-35 is never fun. We blew two more on the way to Thomas the next day and damaged the trailer. Big shout out to Eley’s service center in Watonga and Watonga Machine and Steel for getting us back on the road.

Once we made it Thomas harvest went well. Yields were low, but that was to be expected given the freeze and drought.

Once we made it Thomas harvest went well. Yields were low, but that was to be expected given the freeze and drought.

Questions about Clearfield wheat

The introduction of two-gene Clearfield technology and the release of an Oklahoma-developed two-gene Clearfield wheat variety have resulted in increased interest in the Clearfield system in the southern Great Plains. This has also resulted in several questions, some of which I will attempt to answer in this blog post. If you have specific questions regarding rates, timings, etc., I encourage you to contact your local BASF representative.

Are Clearfield wheat varieties GMO’s? No. The Clearfield system is a non-genetically modified crop herbicide tolerance technology.

What is two-gene technology and what does it mean? As the name implies, two gene Clearfield varieties have two copies of the gene that confers resistance to imidazolinone herbicides. Two gene varieties have “Plus” or “+” in the name (e.g. Doublestop CL Plus). In wheat two-gene technology provides the option of adding 1% v/v methylated seed oil (MSO) to the spray solution. In my experience, addition of 1% v/v MSO greatly increases Beyond efficacy on feral rye. Methylated seed oil should NOT be added to the spray solution for one-gene Clearfield varieties, as crop injury will occur.

What is the new OSU two-gene Clearfield variety? Doublestop CL Plus was released by OSU in 2013 and is marketed through Oklahoma Genetics Inc. It is a late to first hollow stem and late maturity (about the same as Endurance) variety with a wide area of adaptation. A few of the strengths of Doublestop CL Plus include yield potential, acid soil tolerance, test weight, and milling and baking characteristics. More information on Doublestop CL Plus can be found by clicking here.

Doublestop CL Plus

Can I save seed from Clearfield varieties? No. The gene that confers the Clearfield trait is protected by a utility patent and new seed (registered or certified) must be purchased each year.

Can I grow a Clearfield variety two years in a row? The better question might be should you grow a Clearfield variety two years in a row? Multiple years of using the same herbicide or herbicide mode of action can result in herbicide resistance. Of particular concern is jointed goatgrass, which has the ability to hybridize with wheat. This ability to hybridize could result in a population of resistant jointed goatgrass in a fairly short time period. So, if jointed goatgrass is the primary weed problem, rotating crops and/or herbicide chemistries to avoid consecutive years of Clearfield technology is a good stewardship practice.

Other grasses, such as feral rye, do not have the potential to hybridize, but the potential for weed resistance is still there through selection pressure. In these situations, I would not be as concerned about two consecutive years of a Clearfield system, but would certainly switch herbicide chemistry for a year after that.

Ultimately, it is important to rotate crops and herbicide modes of action to ensure the longevity of the Clearfield system. Weed resistance is bad and it is worse if your farm is the epicenter of the problem. Clearfield stewardship guidelines are available from BASF by clicking here

 

 

2013-2014 Wheat fall forage variety trial results

This blog post is an abbreviated posting of our wheat forage results. For the complete report, consult OSU Current Report 2141 Fall forage production and date of first hollow stem in winter wheat varieties during the 2013-2014 crop year by clicking here.

Average daily temperature and rainfall for Stillwater, OK from 09/01/2013 to 03/31/2014

Average daily temperature and rainfall for Stillwater, OK from 09/01/2013 to 03/31/2014

Average daily temperature and rainfall for Chickasha, OK from 09/01/2013 to 03/31/2014

Average daily temperature and rainfall for Chickasha, OK from 09/01/2013 to 03/31/2014

As was the case across most of Oklahoma, our wheat plots were sown into dry topsoil in late September. Soils in southwest and northwest Oklahoma were extremely dry due to multiple years of drought, and wheat pasture was short in these areas of the state. Summer rainfall provided ample subsoil moisture in the central part of the state, but topsoil was largely dry through September. Rains fell across much of the state in October and provided the fuel needed to build wheat pasture. Unfortunately, these October rains would be the only significant rainfall events most of the Oklahoma wheat crop would receive .

 

Fall forage production by winter wheat at Stillwater and Chickasha averaged 3,240 and 2,580 pounds per acre, respectively (Tables below). There was a large group of varieties at Stillwater and Chickasha that produced statistically equivalent forage yield, and producers are encouraged to consider two and three year averages when available.

 

 

Table 2. Fall forage production by winter wheat varieties at Stillwater, OK during the 2013-2014 production year.
Source Variety  2013-2014  2-Year  3-Year
 —————lbs dry forage/acre—————-
Syngenta SY Llano 4,100
AGSECO TAM 113 4,090 3,160 3,220
OGI Billings 3,850 3,200 3,250
LCS LCS Mint 3,690
OGI Duster 3,670 3,180 3,300
OGI Gallagher 3,650 3,230 3,500
LCS T154 3,640 3,040
Syngenta Doans 3,610
WestBred WB4458 3,610 2,920
Syngenta Jackpot 3,600 3,060 3,150
WestBred WB-Cedar 3,560 3,240 3,250
OSU Deliver 3,470 2,770 3,010
WestBred Winterhawk 3,470 2,780 3,020
OGI Garrison 3,350 3,100 3,210
Watley TAM 112 3,230
OGI Doublestop CL Plus 3,200 3,020
OGI Pete 3,160 2,810 3,020
Syngenta CJ 3,130 2,810 2,980
LCS LCH08-80 3,120 2,950
WestBred Armour 3,110 3,000 3,100
LCS LCH11-1117 3,110
OGI Centerfield 3,090 2,820 3,120
OGI OK Bullet 3,090 2,630 2,820
Syngenta SY Southwind 3,090
OSU Endurance 3,080 3,080 3,310
KWA Everest 3,050 2,810 3,010
Syngenta Greer 3,040 2,840 2,960
LCS LCH11-1130 3,040
LCS T158 3,020 2,760 3,000
CWRF Brawl CL Plus 2,980 2,860
OGI Ruby Lee 2,980 2,610 2,900
LCS T153 2,960 2,840 3,090
OGI Iba 2,930 2,770 3,030
WestBred WB-Grainfield 2,910 2,920
WestBred WB-Redhawk 2,850 2,590
LCS LCH11-109 2,750 2,990
OGI OK Rising 2,720 2,720
CWRF Byrd 2,670 2,590
OSU Experimentals
OK09125 2,800 2,540
LSD (0.05) 750 500 400

 

Table 3. Fall forage production by winter wheat varieties at Chickasha, OK during the 2013-2014 production year.
Source Variety 2013-2014  2-Year
–lbs dry forage/acre–
OGI Duster 2,920 2,920
OGI Gallagher 2,920 3,010
LCS T158 2,900 2,580
CWRF Brawl CL Plus 2,830
KWA Everest 2,750 2,750
OGI Doublestop CL Plus 2,700
WestBred Winterhawk 2,680
LCS LCS Mint 2,660
OSU Endurance 2,630 2,620
WestBred WB-Cedar 2,590 2,630
CWRF Byrd 2,540
Syngenta Jackpot 2,540 2,460
WB-Grainfield WB-Grainfield 2,530
WestBred WB4458 2,520
OGI Iba 2,460 2,460
LCS LCH08-80 2,440
OGI Billings 2,420
OGI Ruby Lee 2,420 2,430
OSU Deliver 2,410 2,200
Syngenta Greer 2,380 2,480
Syngenta Doans 2,210
OGI Garrison 2,160 2,220
OSU Experimentals
OK09125 2,760
Average 2,580 2,560
LSD 430 290

First hollow stem data are reported in ‘day of year’ (day) format (table below). To provide reference, keep in mind that March 1 is day 60. Average occurrence of first hollow stem at Stillwater in 2014 was day 77. This was approximately five days later than 2013 and 25 days later than in 2012 and was the result of much cooler than normal temperatures. Unlike previous years, there was only about ten days difference among varieties in occurrence of first hollow stem.

Table 4. Occurrence of first hollow stem (day of year) for winter wheat varieties sown in 2013 and measured in 2014 at Stillwater, OK
Source Variety Stillwater
–day of year–
Syngenta SY Llano 72
WestBred WB-Cedar 72
OGI Billings 74
Syngenta CJ 74
KWA Everest 74
OGI Gallagher 74
Syngenta Jackpot 74
OGI OK Bullet 74
OGI OK Rising 74
Syngenta SY Southwind 74
LCS T153 74
Watley TAM 112 74
AGSECO TAM 113 74
WestBred Armour 77
CWRF Byrd 77
OSU Deliver 77
Syngenta Doans 77
OGI Duster 77
OSU Endurance 77
OGI Garrison 77
Syngenta Greer 77
LCS LCH11-109 77
LCS LCH11-1117 77
LCS LCH11-1130 77
LCS LCS Wizard 77
OGI Pete 77
LCS T154 77
WestBred WB-Redhawk 77
WestBred WB4458 77
WestBred Winterhawk 77
OGI Doublestop CL Plus 80
OGI Iba 80
LCS LCS Mint 80
OGI Ruby Lee 80
LCS T158 80
WestBred WB-Grainfield 80
CWRF Brawl CL Plus 83
OGI Centerfield 83
OSU Experimentals
OK11754WF 69
OK10728W 74
OK09520 77
OK08707W-19C13 80
OK09125 83
OK10805W 83
OK10126 86
Average 77