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UNL Grazing Corn Residue Research

Many stalks in Nebraska are left ungrazed for various reasons.  One reason I’ve heard is the potential impact of increased compaction and reduced yield of the next crop.  Nebraska Extension has long-term research addressing this concern…in fact, 16 years of research conducted at the Ag Research and Development Center near Mead.  There’s various components to this study and you can view the full report at: http://go.unl.edu/8mp6.

In this study, cattle were allowed to graze corn residue in the spring (February to mid-April) or the fall (November through January) and these treatments were compared to an area not grazed.  Corn and soybeans were planted the spring after grazing the residue for 16 years to determine the effect of grazing on the subsequent crop yield.

In the fall grazing treatments, the corn and soybeans were planted no-till.  For corn or soybeans planted into the spring grazing treatments, three tillage treatments were also implemented for nine years:  no-till, ridge-till, and spring conventional till, after which all treatments were converted to no-till.  This result of the tillage by spring grazing treatments for either corn or soybean yield over nine years showed no interaction and suggested the same effect on yield regardless of tillage treatment used after spring grazing.

Table1-Beef

Effect of Corn Residue Removal on Subsequent Crop Yields“, 2015 Nebraska Beef Cattle Report. Mary E. Drewnoski, L. Aaron Stalker, Jim C. MacDonald, Galen E. Erickson, Kathy J. Hanford, Terry J. Klopfenstein

Spring grazing across all tillage treatments did increase soybean yields statistically (58.5 bu/ac for spring grazed vs. 57.0 bu/ac for ungrazed) and had no effect on corn yields.  The results were similar looking at 16 years of grazing vs. not grazing under no-till for both corn and soybeans in the spring; there was no yield effect found for corn and the soybeans showed a slight yield increase with grazing.

Table2-Beef

Effect of Corn Residue Removal on Subsequent Crop Yields“, 2015 Nebraska Beef Cattle Report. Mary E. Drewnoski, L. Aaron Stalker, Jim C. MacDonald, Galen E. Erickson, Kathy J. Hanford, Terry J. Klopfenstein

Looking at a 10 year period of no-till management for both spring and fall grazed corn residue and subsequent corn and soybean crops, fall grazing statistically improved soybean yields over both spring grazing and no grazing (65.5 bu/ac vs. 63.5 bu/ac and 62.1 bu/ac respectively).  No grazing effects were observed on corn yields in either season.  All statistics were at the 95% confidence level meaning the researchers were 95% confident any yield differences were due to the treatments themselves vs. random chance.

Regarding compaction, in the fall, the field was typically frozen and the researchers felt any mud and compaction associated with grazing cattle was minimized; highest subsequent soybean yields were achieved with fall grazing.  The spring treatment was designed to look more at potential compaction and muddy conditions after spring thaw till right before planting-thus the implementation of different tillage treatments as well.  They used a stocking rate consistent with UNL grazing recommendations resulting in removal of half the husks and leaves produced (8 lbs of leaf and husk per bushel of corn grain produced).  Results of this study indicate that even with muddy conditions in the spring, grazing increased subsequent soybean yields compared to not grazing regardless of tillage system used and that corn yields were not different between grazing vs. not grazing and regardless of tillage system used in the spring.  This study was conducted in Eastern Nebraska in a rainfed environment with yields ranging from 186-253 bu/ac with a 16 year median yield of 203 bu/ac.

Additional Grazing Study

A five year fall grazing study (December through January) was conducted in an irrigated continuous no-till corn field at Brule, NE to determine the effect of corn residue removal via baling corn residue or fall grazing on subsequent corn yields.  That environment receives limited rainfall and residue is deemed important for reducing evaporation of soil moisture in addition for catching/keeping snow on fields.  Farmers were questioning the effects of any residue removal on subsequent corn yields and the study was implemented.

Treatments were 1) fall grazing at 1 animal unit month/acre (AUM), 2) fall grazing 2 AUM/ac, 3) baled, or 4) ungrazed.  The researchers found that residue removal did not affect corn grain yields from 2009-2013 in the continuous corn rotation.  There were no statistical yield differences with 5 year average yields of:  152 bu/ac, 155 bu/ac, 147 bu/ac and 148 bu/ac respectively for the above-mentioned treatments.

Table3-Beef

Effect of Corn Residue Removal on Subsequent Crop Yields“, 2015 Nebraska Beef Cattle Report. Mary E. Drewnoski, L. Aaron Stalker, Jim C. MacDonald, Galen E. Erickson, Kathy J. Hanford, Terry J. Klopfenstein

Corn Disease July 2015

Radio advertisements, email blasts, and other media are warning of corn diseases and the need for fungicides.  Two months of humid, wet weather has allowed for disease development.  It’s important to know what diseases truly are in your field before spraying a fungicide, particularly with today’s economics.  Here’s what we’re seeing in fields right now in the Clay, Nuckolls, Thayer, Adams county area.  Based on the diseases we’re seeing, we would recommend you scout your fields to know whether you have mostly bacterial or fungal diseases present.  Consider disease pressure, where on the plant the disease is occurring, growth stage, and economics.  We have had southern rust show up in 10 of the last 11 years I’ve been serving in this area.  If you spray a fungicide at tassel, you may not have enough residual to ward off southern rust when it appears later, potentially resulting in the need for a second application.  In our area thus far, I’m not seeing enough disease pressure in many fields to warrant a fungicide at tassel; consider delaying an application till later for economic and resistance-management reasons.  Ultimately this decision needs to be done on a field by field basis.  Please also see this UNL CropWatch article regarding fungicide application and corn growth stage.  Although I don’t have a photo of it, I’ve also seen common rust in the mid and lower portions of corn canopies thus far.

Anthracnose has been observed in fields for a good month now.  It is mostly seen on lower leaves of plants, particularly in fields where we've had high amounts of rainfall, standing water, and/or hail.  I haven't seen it moving up the plant very far yet.  There are fungicides labeled for this, but we rarely recommend fungicide treatment for anthracnose.

Anthracnose has been observed in fields for a good month now. It is mostly seen on lower leaves of plants, particularly in fields where we’ve had high amounts of rainfall, standing water, and/or hail. Lesions are tan in the center and have a wavy yellow colored margin.  I haven’t seen it moving up the plant very far yet. There are fungicides labeled for this, but we don’t often recommend fungicide treatment for anthracnose.

We saw this disease in the Saronville/Sutton area last year.  This year, we are seeing it throughout Nuckolls, Thayer, Clay, and Adams counties...and most likely others too.  Some hybrids (and have seen this across companies) are highly affected by this bacterial disease.  We have informally called it

We saw this disease in the Saronville/Sutton area last year. This year, we are seeing it throughout Nuckolls, Thayer, Clay, and Adams counties…and most likely others too. Some hybrids (and have seen this across companies) are highly affected by this bacterial disease. Neither last year, nor this year, has the pathogen causing this disease been confirmed. Plants will have vein-limited lesions in streaks on the leaves. It is often confused with gray leaf spot early on.  Take a hand-lens and looking closely, you will see wavy margins on the lesions which doesn’t usually occur with gray leaf spot.  Over time, these lesions become elongated and can coalesce with other lesions. Also looking closely with a handlens or microscope, one finds the leaf tissue eventually becomes transparent. While other diseases can look similar to it, under the microscope, no fungal spores are found other than secondary ones. Putting an infected leaf in water reveals cytoplasmic streaming in which the bacteria is escaping the leaf tissue. (The pathogen causing Goss’ wilt also does this, but this disease is not the same as Goss’ wilt). Fungicides will not cure bacterial diseases and the products advertised for targeting bacterial diseases haven’t been researched for this disease.  This is the primary disease we are seeing in our area right now-and it looks nasty in some fields!  Unfortunately there’s nothing we can do about it.  If you are considering testing one of the products for bacterial diseases, please let me know as I’d appreciate testing it with you via on-farm research.

Goss' wilt (bacterial disease) has been observed in fields as well.  I typically notice it along field edges, pivot tracks, pivot/well roads or hail-damaged fields as plant wounds in general allow an entry for bacterial pathogens.  However, research has shown that the bacterial pathogen causing Goss' wilt can enter through the leaf stomates as well.  Leaf miner damage can be observed at the top of this photo, and often, but not always, I notice this occurring together in fields.  There is nothing we can do for Goss's wilt if you have this disease in your fields right now.  There are products targeting bacterial diseases on the market.  If you're interested in trying these, please consider an on-farm research experiment to prove the efficacy to yourself and help us obtain data.

Goss’ wilt (bacterial disease) has been observed in fields as well. I typically notice it along field edges, pivot tracks, pivot/well roads or hail-damaged fields as plant wounds in general allow an entry for bacterial pathogens. However, research has shown that the bacterial pathogen causing Goss’ wilt can enter through the leaf stomates as well. Leaf miner damage can be observed at the top of this photo, and often, but not always, I notice this occurring together in fields. There is nothing we can do for Goss’s wilt if you have this disease in your fields right now. There are products targeting bacterial diseases on the market. If you’re interested in trying these, please consider an on-farm research experiment to prove the efficacy to yourself and help us obtain data.

Physoderma brown spot typically doesn't occur in our area until tasseling (which is where we are at now in some fields).  However, I was seeing this as early as two weeks ago on some hybrids.  The pathogen causing this disease is a fungal-like pathogen that moves with water.  You will notice a purple/brown color on midribs of leaves, leaf sheaths, stalks, and tiny yellow/brown/purple spots on leaves.  This disease isn't considered yield-limiting or of significance to us in Nebraska.  Some confuse this disease with southern rust, but there are no pustules produced with Physoderma brown spot.

Physoderma brown spot typically doesn’t occur in our area until tasseling (which is where we are at now in some fields). However, I was seeing this as early as two weeks ago on some hybrids. The pathogen causing this disease is a fungal-like pathogen that moves with water. You will notice a purple/brown color on midribs of leaves, leaf sheaths, stalks, and tiny yellow/brown/purple spots on leaves. This disease isn’t considered yield-limiting or of significance to us in Nebraska. Some confuse this disease with southern rust, but there are no pustules produced with Physoderma brown spot.

The larger, rectangular lesion is typical of gray leaf spot found in some lower leaf canopies right now.  It is easy to confuse with anthracnose as both diseases appear a little different on various hybrids.  Gray leaf spot will be vein-limited while anthracnose is more blotchy in appearance.

The larger, rectangular lesion is typical of gray leaf spot found in some lower leaf canopies right now. It is easy to confuse with anthracnose as both diseases appear a little different on various hybrids.  Gray leaf spot will be vein-limited while anthracnose is more blotchy in appearance.  Comparing gray leaf spot with the unknown bacterial disease, the lesion edge will be straight for gray leaf spot and wavy for the bacterial disease.

Northern corn leaf blight is a disease we're hearing a lot about but I have yet to see it in our area.  Most have been mistakingly calling the unknown bacterial disease shown above northern corn leaf blight, but there's truly a difference as you see these photos.  Compared to gray leaf spot, northern corn leaf blight will be more cigar-shaped instead of forming a rectangle.  As this photo taken from the Mead, NE area shows, lesions are often forming in close proximity to each other on the leaves in Nebraska right now.  This disease is one to watch as it has been expanding on certain hybrids in some fields, particularly in eastern, Nebraska.  However, I still haven't seen it in our area and haven't received any confirmations of it being found in our area.

Northern corn leaf blight is a disease we’re hearing a lot about but I have yet to see it in our area. Most have been mistakingly calling the unknown bacterial disease shown above and even Goss’ wilt, northern corn leaf blight, but there’s truly a difference as you see these photos. Compared to gray leaf spot, northern corn leaf blight will be more cigar-shaped instead of forming a rectangle. As this photo taken from the Mead, NE area shows, lesions are often forming in close proximity to each other on the leaves in Nebraska right now. This disease is one to watch as it has been expanding on certain hybrids in some fields, particularly in eastern, Nebraska. However, I still haven’t seen it in our area and haven’t received any confirmations of it being found in our area at this time. (Photo courtesy of Aaron Nelson, Nelson Precision Agronomics).

It’s Fair Time!

orangeout at fair

This week is the Clay County Fair! We hope you will come out to view the 4-H and Open Class exhibits, 4-H/FFA youth showing their animals, family fun night, 4-H Council Bar-B-Q, cattle sorting, mutton busting, Amanda Winter concert, mud drags, and much more! I absolutely love our fair for the focus on youth and families! I also enjoy watching the fairgrounds come alive with excitement from youth and families as they bring their projects and show them. It’s such a blessing to work with wonderful people who desire what’s best for the youth! A full schedule of events can be found at http://clay.unl.edu. See you at the fair!  (photo is of those wearing “orange out” t-shirts the last day of the fair in 2014-Photo courtesy of Tory Duncan, Clay County News).

Determining Your Needs

In the Clay County Fair Open Class flyer printed in the Clay County News, you will find the middle page pulls out and is a survey. Nebraska Extension in Clay County and our Clay County Extension Board have launched a survey to determine programming/information needs you deem critical to you and your families. We know that we provide crop, 4-H, and some horticulture programming and information, but there is much more that Nebraska Extension as a whole provides that we haven’t necessarily offered as much as we could in Clay County.

The survey is meant for those of you in Clay County, if you’d be willing to take less than 5 minutes to fill it out, we’d greatly appreciate it! You can also fill it out online at: https://www.surveymonkey.com/r/clayext. The survey will remain open till the conclusion of the Clay County Fair on July 12 this year. Please pass this information along to Clay County constituents as we’re trying to reach as many people as possible. It really is important that we receive as much feedback as possible. It’s important as the goal is to better serve you-and we can’t do that without your input! Please do take a few minutes and complete this for us as we’ve only had a handful complete it thus far. Thank you and please encourage others to complete it as well!

Sugar Application in Crops

Corn is approaching or at V7-V8 growth stage.  A few weeks ago, we published research results in our UNL CropWatch website.  That information can be found in the links below the video.  If you are interested in trying this in your field this year, please see the Nebraska On-Farm Research protocals also shown below.

Weed Science Field Day

July 1 is the upcoming Weed Science Field Day at UNL’s South Central Agricultural Laboratory near Clay Center.  The brochure with more information is shown below as photos; please click on the photos to enlarge if they are difficult to read.  You may RSVP to Dr. Amit Jhala at (402) 472-1534.  Hope to see you there!

SCAL Weed Field Day1SCAL Weed Field Day2

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