Category Archives: Research
Evergreen Problems Webinar will be on April 22 from 7-8:30 p.m. Please call Platte County Extension at 402-563-4901 to RSVP. They will send you the Zoom link and password. There is no fee.
Considering Carbon: opportunities and challenges webinar will be held April 21 at 11 a.m. CST. Info & registration here: https://nationalaglawcenter.org/webinars/climate21/. There is no fee.
Reminder: Household Hazardous Waste Collection April 24th for Seward (8 a.m.-Noon) and Butler (1:30-4:30 p.m.) counties.
Soybean germination and planting: When I first began Extension, research on early soybean planting was just beginning. At the time, I hadn’t thought about planting soybean at the same time as corn, or even before corn. Soybean genetics and seed treatment improvements have allowed for this. Our recommendation for increased yield is to aim for planting the last few weeks of April if conditions are right, use a seed treatment, and plant 1.75-2″ deep. It seems like each year during planting season, we experience 1) soil temps in the mid-40’s with solid soil conditions and on a warming trend and 2) the potential for cold snaps with cold rains/snow after planting. What should one do and what’s the time-frame for risk of chilling injury?
For soybean, and corn for that matter, I’m not as concerned about #1 if the soil is fit and proper seeding depth (2”) is maintained. For #2, if the soil conditions are right and there’s at least 24 hours before a cold snap, consider planting beans instead of corn. That’s because soybean imbibes (takes up) water more quickly than corn. Once that imbibitional period is completed, the risk of chilling injury also ends. The seed can then remain (in osmotic phase) at cooler soil temperatures for a period of time in a sort of ‘dormant state’, until warmer temperatures return for continued seedling development.
In March 2021, Dr. Jim Specht and I began indoor and outdoor demonstrations. To be clear, we’re not recommending planting soybean in March in Nebraska. And, the point of these studies wasn’t to encourage increasing risk of pushing planting prior to cold snaps. I’m grateful for conditions like this year that make the decision to not plant easy when we know it’s staying cold with precipitation in the forecast. Our demonstrations just provided time looking at windows of 40-50F soil temps and increasing/decreasing trends. Soybeans are just beginning emergence from the March 10 planting in York. Soil temps in soybean and corn residue and living rye cover crop have been monitored since then and can be seen in an article at cropwatch.unl.edu. The soil under rye cover was 1-5 degrees cooler than under corn residue which was 1-2 degrees cooler than under soy residue.
We used coolers at 60F and 36F at the York Co. Fairgrounds to conduct an indoor experiment, explained in more detail at cropwatch.unl.edu. Enough trays were planted with soybean and corn seed so they could be switched between the coolers every 2 and then 12 hours for a total of two days. We didn’t have space for replications. All trays were removed to my house after 72 hours. They were kept at 50F for 9 days (which in many cases, early planted soybean do set in the soil for a period of time before emergence). Then they were kept at 60F soil temp with emergence counted each day until termination April 8. In the soybean, similar percent emergence was found in the 60F control; and where soybeans were at 60F for 8, 10, 12 and 48 hours before switching to 36F. This showed that we no longer saw reduced emergence upon 8 hours prior to a cold snap (in this non-replicated experiment). This potential 8 hour critical period has been within the time-frame of published research studies and non-published field observations.
The 36F to 60F switch showed that a warming trend in the first 2-6 hours led to greater emergence. We don’t recommend planting into soils at 36F, but it served as a nice low extreme. We would anticipate the emergence would improve if the soil temp was 40F or mid-40’s with a warming trend.
What does this mean? If soil conditions are right for planting and seed is planted around 2” deep with a seed treatment, I’m not as concerned about planting soybean or corn at 45F soil into a warming trend. For planting prior to cold snaps, if one chooses to do this, we say aim for at least 24 hours for soybeans and 48 hours for corn. We know not every soybean field is completely planted at 24 hours prior to a cold snap, so to me, this gives some insight why we’ve seen fields, including two on-farm research ones in Seward county last year, still have 86% emergence prior to snow falling eight hours later. Also key is when the beans will emerge compared to frost potential. If the beans are in the ground or have cotyledons exposed, we haven’t observed a need to replant due to frost damage thus far. It’s when the hypocotyl hook is at the soil line that can result in replant potential. Thanks to York Co. Ag Society for use of their coolers, Jerry Stahr for use of his field, Jed Erickson for providing the corn and soybean seed, and Dr. Jim Specht for his help in spite of being retired!
March is a month where I spend some time planning on-farm research and other experiments. One topic that surfaced during our on-farm research meetings in February was potentially testing the fungicide product Xyway™. This product is unique in that it is applied in furrow and can be applied with starter fertilizer at planting. It moves systemically in the plant through the water carrying vessels (xylem). For growers who are near towns or locations where aerial applications are restricted, a product like this is intriguing and could have a unique fit.
There’s limited university research with the product, but the findings have been intriguing thus far. The LFR® and 3D versions (in furrow at planting) were tested in Kentucky compared to untreated check and foliar fungicide products (Lucento® and Headline AMP®) applied at R1 in corn. In 2019, Xyway™ LFR® and sometimes the 3D version also showed the same efficacy for northern corn leaf blight (NCLB) and even gray leaf spot (GLS) compared to products applied at R1. All the products had less disease severity compared to the untreated check. Xyway™ did not reduce southern rust disease severity. In 2020, low disease pressure in general was observed in the Kentucky locations. The Xyway™ still provided the same disease reduction to GLS as foliar products applied at R1, which were all significantly less than the check.
In 2020, Dr. Tamra Jackson-Ziems also had a study at UNL South Central Ag Lab near Clay Center. The study compared different application timings (at planting, R1 and R3) of different products compared to an untreated check. Xyway™ LFR® was applied with starter at 15.2 oz/ac at planting. This was compared to Xyway™ at planting + 5 oz/ac Lucento® applied at R1. A number of foliar fungicide products were applied at R1 and R3. The Xyway™ LFR® applied at planting showed no disease difference compared to the untreated check for southern rust. All the other products and timings reduced the amount of southern rust compared to the untreated check. Traditionally, we’ve seen fungicides provide improved standability. In 2020, there were no differences in lodging for any of the products or timings compared to the untreated check. Regarding yield, the Xyway™ LFR® at planting yielded better than the check, whereas there was no yield difference with the Xyway™ + Lucento® at R1. Looking at the data, there were no yield differences between applying foliar fungicide at R1 vs. R3 for any of the products except Miravis® Neo. And, sometimes a product didn’t show a difference between other products or even the untreated check. I show a picture of the data on my website jenreesources.com. With last year being a heavy southern rust year, being able to wait till R3 to apply a fungicide provided some additional time for the residual to work when southern really came on. I know some had to apply a second fungicide application when they automatically applied at R1; that’s just tough from an economic and resistance management perspective.
Because I’ve got nearly a handful of growers interested in testing Xyway™, I put together protocols at jenreesources.com if you’d also like to check them out. If you’re interested in testing any study via on-farm research, please contact me or your local Extension educator.
Solar Energy Webinars: These webinars are free and for anyone who is interested in solar. What is the payback for Solar PV systems? A common question with not such as easy answer. Farmers and businesses are receiving marketing materials to invest in solar, yet the economic feasibility of solar is not always clear. This webinar series will cover how solar electric systems work, how to determine the value of energy and how the complexity of subsidies and policy make general statements about feasibility more complex. This workshop will cover these issues in detail and provide participants with the information they need to speak confidently with farmers about solar electric systems. All webinars are held from 9:00-10:30 a.m. on March 30, Apr. 1, Apr. 6, Apr. 8. Registration at: https://unl.zoom.us/meeting/register/tJEod-qhrz0sHdYkpW9nRnfdsv0wlk78bW99. Those with specific questions can reach out to John Hay, Nebraska Extension Educator at 402-472-0408 or email@example.com.
Cold Weather and Livestock: This week I found gratitude time and again for a warm home. Thinking of those who haven’t been as fortunate. Have also thought about our livestock producers taking care of animals. In the unfortunate event of livestock losses, please document/take photos in the event of any disaster declarations for livestock indemnity payments (LIP).
Crop/Livestock Systems On-Farm Research Study: At last week’s cover crop and soil health conference, Ken Herz shared on his family’s on-farm research study. I’m so proud of and grateful to the entire Herz family for their partnership in this study and for the focus on the economics of an entire system! This study was designed with a system’s perspective incorporating crops, cattle, cover crops in a way that fit many operations in a non-irrigated setting. Their goals were to increase soil organic matter and ultimately determine yield and economics of the entire system. The crop rotation is Wheat (with cover crop planted into stubble after harvest), Corn, Soybean. Cattle graze the cover crop in the winter and also graze the corn residue. No-till wheat prior to corn for increased moisture saving and yield is common in this part of the State as is planting a cover crop into wheat stubble for grazing. The questions I hear include:
1-What moisture and potential yield am I giving up to the successive corn crop if I plant a cover crop into my wheat stubble?
2-If there’s a yield loss in the successive corn crop, do the economics of grazing the cover crop offset that loss?
We had three treatments and two locations (Location 1 had a cool-season cover crop and Location 2 had a warm-season one). The treatments are: ungrazed wheat stubble, ungrazed cover crop, and grazed cover crop. We’ve collected soil property, moisture, nutrient, and health data; yield and moisture of each crop; cover crop biomass; grazing days; and economics.
Location 1 in Nuckolls county began in 2016 with a cool season cover crop planted after wheat was harvested and manure applied. Three-year analysis showed no difference in soil physical properties (bulk density and compaction) amongst treatments. There was greater total microbial and fungal biomass in the grazed cover crop treatment (indicators of improved soil health). Interestingly, the ungrazed wheat stubble is the most economical treatment at this location. Reasons: cost of hauling water for grazing, numerically higher yields in the ungrazed wheat stubble, variable biomass in cool season cover, and a large yield hit to the 2018 soybeans in the grazed cover crop treatment during a dry year. In 2018, to the line there was a stress difference in the soybeans and that treatment read drier via soil moisture sensors. They’ve been conservative with grazing so at the time we couldn’t explain it. In taking soil health tests in year 3, we realized how greatly the microbial biomass had increased where cattle grazed. Our hypothesis is microbes broke down the remaining residue exposing soil to more evaporative losses resulting in less soil moisture and less yield for soybeans in the grazed treatment during a dry year. It’s now on our radar when grazing occurs to get cattle off even sooner to account for feeding the microbes too.
Location 2 in Webster county began in 2018 with a warm season cover crop. Over 4 tons of biomass allowing for 91 grazing days, not hauling water, and no successive crop yield differences all led to the grazed cover crop being the most economical treatment at this location.
Take home points: it’s important to add all the components when looking at economics. Grazed cover crop treatment at Location 1 would look better if we didn’t include the large cost of hauling water and if there was more cool season biomass allowing for more grazing days. The differing results at the two locations showed the influence of cover crop biomass and importance of including value of grazing; fencing/water/labor costs for livestock; cover crop costs; and successive crop yields in system economics. It’s easy to make assumptions that a certain practice is profitable! Location 1 will hopefully continue another 6 years switching the cool season cover crop to a warm season one to compare economics on the same field. We’re curious if the warm season cover will increase biomass and grazing days enough to outweigh the water hauling costs and show a benefit to the grazed cover crop treatment, or if the ungrazed wheat stubble will remain the most economical for this field location.
Regarding cover crop economics, it could be helpful to determine a consistent way for assessing a dollar value for potential benefits such as aiding in weed and erosion control, nutrient uptake, etc. This may aid conversations with landlords and lenders for those desirous to try them. Without livestock value, currently on paper, there’s really only costs.
(End of news column. Photos below are additional information.)
Nitrification Inhibitors: For the next several weeks I will share data from on-farm research studies. Nitrification Inhibitors are best thought of as an insurance policy against loss of applied ammonium-based fertilizer due to excess rain in the first month or so after fertilization. For spring applications, some active ingredients have been proven by research to slow the conversion of ammonium to nitrate for at least two weeks, with a range of 1-6 weeks, depending on soil temperature. They are one tool (not a silver bullet), when used at right place and time, for aiding in nitrogen management. To summarize the research below, nitrification inhibitors are less likely to have a significant impact on increasing yield and reducing nitrate leaching in silt loam and silty clay loam soils as compared to sandy soils.
An ongoing study at UNL’s South Central Ag Lab (SCAL) near Clay Center is conducted on silt loam soils, common in the UBBNRD. The majority of the study at SCAL compared Spring pre-plant anhydrous vs. side-dress application with and without the use of nitrification inhibitor N-Serve® (nitrapyrin). A yield increase due to nitrapyrin applied pre-plant was observed in 6 of 28 years with a mean yield change of 2 bu/ac/year. Only 1 of 28 years was a yield increase observed when nitrapyrin was applied in season during side-dress application with a mean yield change of 0 bu/ac/year. In this study, they found delayed side-dress N with nitrapyrin could reduce plant N uptake and release N too late, thus it is not recommended to add an inhibitor to nitrogen applied in-season.
In 2019, two York Co. farmers compared spring anhydrous ammonia applications with and without the nitrification inhibitor (N-Serve®). At York location 1, 180 lbs N as anhydrous was applied on April 10, 2019 in ridge-till, silt-loam soil. At York location 2, 160 lbs N as anhydrous was applied on April 8, 2019 in no-till, silt-loam soil. These locations were around 4 miles apart and the previous crop in both was soybean. Soil samples were taken 2” off the anhydrous band down to three feet for both ammonium and nitrate concentrations at V7 growth stage. The results showed the nitrification inhibitor was still slowing the conversion of ammonium to nitrate in 1st foot at York 1 location (longer than would be anticipated for a spring-applied inhibitor treatment), but not at York 2. At both study locations, no yield difference occurred between the check and inhibitor treatments respectively (250 vs. 251 bu/ac at York 1 and 264 vs. 264 bu/ac at York 2).
In 2020, four farmers (3 in York Co. and one in Fillmore Co.) conducted on-farm research inhibitor studies. These studies were in partnership with the UBBNRD. Soil samples for ammonium and nitrate concentration were taken around 6 and 9 weeks post-application based on the protocol provided. Note: with these being inhibitor focused studies, future protocols will have soil tests taken closer to application. With farmers interested in what nitrogen distribution in the profile looks like in the late season, we will also sample then.
At York location 1, 150 lbs N as anhydrous was applied in the fall and spring with and without Centuro®. Soil tests in early May showed less total nitrogen in the third foot for the Spring anhydrous with Centuro® compared to Fall anhydrous with no inhibitor. There were no yield differences between treatments in 2020 (Fall and Spring check yielded 269 bu/ac, Fall with Centuro® 267 bu/ac, Spring with Centuro® 270 bu/ac). This study will continue. The other three locations had yields impacted by the July 9, 2020 wind event. At the Fillmore Co. location, 115 lbs spring applied 32% UAN with and without Instinct® II was compared. There was less nitrate and total nitrogen in the Instinct® II treatment at 2nd and 3rd foot vs. the check and there were no yield differences (both yielded 213 bu/ac). At the York 2 location, four products were compared (44 gal. spring applied 32% UAN as a check compared to the check plus either ammonium thiosulfate (ATS), Biovante™, or Instinct® II. The UAN+ Instinct® II had less nitrate and total nitrogen in the 3rd foot than the UAN+ Biovante™. The UAN+ATS treatment yielded significantly more than the check (215 bu/ac vs. 209 bu/ac) with no differences amongst the other treatments (212 bu/ac each). At the York 3 location, 45 gal spring applied 32% UAN was compared to a producer-developed concoction containing humic acid, sugar, and ATS. There was more nitrate, ammonium, and total nitrate in the inhibitor concoction than the check at the 3rd foot with no yield differences (220 bu/ac check vs. 221 bu/ac inhibitor concoction). These and other Nebraska on-farm research studies will be presented Feb. 25-26 both virtually and in-person. You can learn more and register here: https://go.unl.edu/h83j.
On-Farm Research: Last week a team of us did a series of meetings throughout the State regarding on-farm research updates. It’s always great to have the farmers presenting their research and adding in additional details that we didn’t have when the results booklet was published! Two more meetings continue in western Nebraska this week.
Perhaps my biggest reason for strongly promoting on-farm research is because there often is no better way to obtain answers to some of the questions you all have. These types of studies are often difficult to obtain funding (or can take months to obtain funding, resulting in a lost window of opportunity) and by conducting this research on your farms, we obtain the answers for your specific situations. Sometimes challenges such as storm damage also become opportunities to answer a question via on-farm research. Growers tend to appreciate research conducted on other growers’ farms when we share this research at various meetings, field days, and in articles. A variety of topics are researched every year including nutrient management, various products, row spacing, and new technologies including multi-hybrid planters, use of drone sensors, etc.
In this week’s UNL CropWatch at http://cropwatch.unl.edu, three on-farm research cooperators are featured. One of these is Ken Herz along with sons Zach and Aaron in the Lawrence, NE area as first-time cooperators. Ken approached me with several questions the winter of 2015. As growers with a non-irrigated, no-till wheat/corn/soybean rotation and a cattle operation, his family was curious about the impacts of grazing cover crops for cattle gains and improving soil organic matter. They were also curious about the trade-offs of the cover crop vs. any soil moisture loss or impact on the successive corn yield. They also wanted this study to be something that would be applicable to what farmers in this area did and something they could all learn from together. Thus, it was decided to not plant cover crops into the corn or soybean residue as that isn’t common and this would need to be a long-term study. Dr. Mary Drewnoski and I met with the Herz family to develop a plan for this study. Also thankful for Dr. Suat Irmak for his help in providing additional soil moisture equipment and advice I needed, to the Little Blue NRD in partnering with reduced cost of soil moisture equipment and also for the partnership of Green Cover Seed.
In 2016-2017, this study evaluated four treatments on the effects of successive corn yield: 1-ungrazed wheat stubble 2-grazed wheat stubble 3-ungrazed cover crop 4-grazed cover crop. Wheat was harvested July of 2016 and a five-species cover crop mix of spring triticale, winter peas, oats, collards, and purple top turnips was planted August 14, 2016 (they wanted a mix that would winter-kill). The cover crop received moisture within a week of planting that allowed for germination. Some additional fall moisture allowed for good growth and cover crop biomass was measured (3401 lb/ac) prior to grazing 28 (1100 lb) first-calf heifers for 22 days resulting in the cover crop carrying 2.4 animal unit months (AUM)/ac. The goal was not to graze too heavy to allow for ground cover and any long-term soil improvements, thus 2177 lb/ac of biomass was present post-grazing. Soil moisture was monitored from after cover crop planting through corn harvest. The soil was so dry after wheat harvest prior to planting the cover crop that it took using a drill to install the second and third foot moisture sensors. Beginning soil health parameters were also taken to be compared long-term in this study.
Corn was planted May 15, 2017. Prior to planting the corn, the soil moisture where the grazed and ungrazed cover crop plots were located were at 35% depletion (top three feet) compared to at field capacity (full soil moisture profile) in the grazed and ungrazed wheat stubble plots. Eight inches of rain in May evened out the soil profile allowing all plots to be at a full profile (top four feet) at the beginning of the corn growing season. As the season progressed, the grazing treatments started separating out from the ungrazed treatments from July through end of the season. I don’t know how to explain that yet.
Corn was harvested the Thursday of the major wind event with a calibrated grain wagon. Yields were not statistically different and were 218 bu/ac, 211 bu/ac, and 213 bu/ac for the ungrazed wheat stubble, grazed cover crop, and ungrazed cover crop respectively. The grazed wheat stubble treatment yielded 212 bu/ac but only had two reps at the end of the growing season so was not included in the statistical analysis. Economically, grazing the cover crop was as competitive as the ungrazed wheat stubble treatment when it came to ensuing corn yields and the spring rains made all the difference in beginning soil moisture. Because of the crop rotation, there wasn’t an opportunity to add a cover crop in this field Fall 2017. The Herz’ feel they lost an opportunity as environmental conditions vary so much every year, and this year, cover crops didn’t have as much growth in area fields. Thus, they’ve chosen to dedicate three fields to this study topic in the future, allowing for one of the fields each year to have wheat/cover crop/grazing to account for environmental variation. Continuing this for the next 5-7 years will better answer their questions while benefiting all of us with what is learned. Perhaps other growers are interested in some variation of this study for your farms?
Most studies are not this in depth and this is just one example of how growers are answering questions they have for themselves via on-farm research. It can take extra time at planting, harvest or other times of the season depending on the study. I believe most growers I’ve worked with would say the effort has been worth it to scientifically answer their questions for themselves. Truly am grateful for all of you I’ve had the opportunity to work with via on-farm research! So, if you’re thinking about a question you’d like to answer on your farm this year, consider reaching out to me or your local Extension educator and we’d be happy to talk with you now about how to set up your study. It is important to talk this through, especially if this is your first time conducting research. If you’d like to learn more about on-farm research, view some protocols, or view results from previous studies, please check out our website at http://cropwatch.unl.edu/farmresearch.
Bake and Take Month: March is Bake & Take month, a time when wheat organizations encourage others to bake a wheat good and share it with family, friends, neighbors, co-workers and shut-ins. In honor of the month, the Nebraska Wheat Board (NWB) is again sponsoring recipe cards and stickers for any 4-H groups or other organizations that wish to participate. This year’s recipes are mini dessert tacos and crockpot cherry chocolate lava cake. Those interested in participating or who have questions can contact the NWB office at (402) 471-2358 or firstname.lastname@example.org. There is no cost for the supplies, and no limit on the number that can be requested. Those wishing to preview the recipes before requesting materials can find them listed at http://wheat.nebraska.gov starting March 1.
York County Fair Volunteers: Gary Zoubek asked me to mention he’s looking for a few volunteers that could help with 4-H and Open Class primarily on entry and judging day in Ag Hall on July 31 and August 1st. If you’re interested, please contact Gary at 402-326-8185 or email email@example.com.
March 10th marks the third annual Nebraska Ag Water Management Network Conference with 2016 being the 11th year since the Network was formed! If you’re interested in learning how you can better schedule your irrigation in addition to learning about the latest in irrigation research from Nebraska Extension, consider attending this free event!
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.
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.
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.
Grazing corn residue provides many benefits to both livestock and grain farmers, yet many corn stalks in our area are not grazed for various reasons. With as much hail as we’ve had this fall, grazing is also an option to remove ears and kernels that were lost, preventing volunteer corn next season. Normally there is less than a bushel of ear drop per acre, but we most likely have more than that in some of our fields this year. Two kernels per square foot or one ¾ pound ear in 1/100 of an acre is the equivalent of 1 bu/ac yield loss. In 30” rows, 1/100 of an acre is 174’ long if you count in one row or 87’ if you count in two rows.
What may also be of interest to you is a recent finding between corn grain loss pre-and during harvest and sudden death syndrome (SDS) of soybean. Many asked me this this year, “Why did I see SDS this year when we’ve never had it in this field before?” It’s a great question and I often responded by saying we need to sample the areas affected with SDS for soybean cyst nematode (SCN) as the two diseases are synergistic. Sampling for SCN still remains free through your Nebraska Soybean Board Checkoff dollars and you can stop by the Extension Office for free sampling bags. Crop consultants should contact the UNL Plant and Pest Diagnostic lab directly at (402) 472-2559 if you are requesting 10 or more sampling bags.
Anything that moves soil can transport the fungal soil-borne pathogens causing these diseases. But recent research from Iowa State University also suggests that the fungal pathogen causing SDS (Fusarium virguliforme) survives on grain lost during the harvest process in fields and that SDS management in soybean actually needs to begin at corn harvest.
Studies were conducted for two years in greenhouse and in field plots with nine treatments to determine the survivability of Fusarium virguliforme (Fv) on corn and soybean residue. The treatments were: 1-Corn kernels + Fv; 2-Corn roots + Fv; 3-Corn stem/leaves/husk + Fv; 4-No residue + Fv; 5-Soybean seeds + Fv; 6-Soybean stem/leaves/pods + Fv; 7-Soybean roots +Fv; 8-Corn stalk on soil surface + Fv; 9-Corn kernels and stalk on soil surface + Fv. The researchers consistently found in both the greenhouse and field experiments that Treatment 1 of corn kernels at average harvest loss resulted in the most SDS. Treatment 2 consistently resulted in the second most SDS.
This helps to explain why some farmers are finding SDS in fields that have been continuous corn for a period of years, are finding SDS in corn and soybean rotation when little or no SDS was previously observed, and why SDS has increased in seed corn fields that may have higher harvest losses. They did not experiment with tillage systems and their recommendation is to reduce harvest losses to reduce the risk of SDS.
Grazing residues can reduce your risk from these harvest losses and for those losses which were incurred with the hail/wind storms we’ve experienced since Labor Day. When grazing corn residue, cattle are selective. They will eat the grain first followed by the husk and leaf followed by the cob and stalk.
It’s also important to be aware of grazing restrictions from herbicides applied to row crops; you can read more about that in this post.
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.
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!