Reducing Soybean Seeding Rates: Can I reduce soybean seeding rates and still maintain yield? It’s a common question from soybean growers, especially those seeking to reduce input costs. Every year during winter meetings I share what our growers have found. We now have 11 years of On-Farm Research proven data.
The findings? Reducing soybean seeding rates from 180,000 or 150,000 seeds/acre to 120,000 seeds/acre doesn’t statistically reduce yields in 30- or 15-inch rows in silty clay loam and silt loam soils in south-central and eastern Nebraska. Results of 18 studies showed for seeding rates of 180K, 150K, and 120K seeds per acre, average yields were 69.0, 68.7, and 68.4 bu/ac, respectively (Figure 1). The early studies within this dataset all had seed germination of at least 90% listed on the seed bag. In all but two situations (seeded at 180,000 and achieving 88% germination), the growers were able to achieve 90% or greater of their planted stand.
As I share this data, I’ve often heard “but I seed higher rates because of X, Y, or Z…”; however, this dataset includes a lot of those reasons without negative yield consequences! I’ve worked closely with these studies in walking the fields; taking notes and pics; counting plants, pods, and seeds; so I’m really confident of the research and the fact that soybeans truly compensate for reduced populations! Outside of this research, I’ve also observed this in many soybean hail, crusting, and PPO inhibitor seedling damage situations. This dataset includes:
- The latest soybean varieties as the research was conducted from 2006-2017.
- Erect and bushy type varieties in growth architecture.
- Higher and lower yielding situations.
- Fourteen irrigated fields and four non-irrigated.
- Hail events occurring from cotyledon stage to R2 in some of these fields.
- Crusting in some non-irrigated fields.
- Seed treated in some fields and others without (determined by grower’s planting date).
- In some years, pod and seed count data were also collected; the data showed similar numbers of seeds/acre and ultimately yield per acre.
- Observations of increased plant branching at lower seeding rates and difficulty in telling the seeding rate treatments apart as the season progressed.
Our research data for 11 years shows no statistical yield differences in seeding rates from 120,000-180,000 seeds/acre in 15- or 30-inch rows in silty clay loam or clay loam soils. Thus, reducing seeding rates is a way to consider reducing input costs for 2018 without impacting your yield. If you dropped your seeding rate from 150,000 seeds/acre to 120,000 seeds/acre, you could save $10.08/acre, assuming a yield loss of 1 bu/ac, a seed cost of $60 per 140,000 seeds, and a savings of $25.71/ac on seed.
- Thus, if you plant between 140,000-160,000 seeds/acre, consider dropping your seeding rate to 120,000 and aiming for a final plant stand of 100,000 plants/ac based on our research findings.
- If you plant at 180,000 or more seeds/acre, consider dropping your seeding rate to 140,000 seeds/acre as a step-wise increment.
Still hesitant? Consider trying this yourself for your location! Consider using either this Two Population Treatment Design or Four Population Treatment Design. You also can download the Nebraska On-farm Research app, available in Apple and Android, to help you set up your plot design to obtain scientific results. If you have questions or need help setting up your research project, please contact me or anyone involved with our Nebraska On-Farm Research Network. To view all the graphs and additional data regarding 15″ row spacing with reduced seeding rates, please check out this week’s UNL CropWatch at http://cropwatch.unl.edu.
Beginning Soil Moisture: On Good Friday, I installed soil moisture sensors down to 4′ in non-irrigated no-till fields at Bladen and Lawrence. Last week I added three more sites at Clay Center, Superior and Byron. Thus far, the 3′ and 4′ are dry in all those locations other than Clay Center (only dry at 4′). At Superior, I could only get the soil probe in the ground 6″ into actively growing rye and 1′ in cover that winter-killed. I was just curious what kind of moisture existed currently in the southern tier of counties. I realize planting plans are in place and that we often receive rains in April/May. Hopefully it provides information that can be helpful in how to use that soil moisture. If we don’t get necessary rains, you may consider switching to a different crop, growing feed if you have cattle, or not terminating actively growing rye as originally planned but perhaps using it for feed. Will share graphs next week and I appreciate the growers allowing me to install these in their fields!
My top question the past two weeks has been about dicamba training. I just received the information regarding this training from our pesticide program coordinators.
First, to clarify some mis-understandings: Dicamba training is required for those applying the following dicamba products: XtendiMax®, FeXapan™, and Engenia®. These products are all Restricted Use Pesticides (RUP) this year; thus, you have to be a certified applicator to purchase and use these products. Dicamba training is not required if you’re applying dicamba corn products (unless it is the above-mentioned products).
Second, pesticide training of any kind is not the same as dicamba training. Dicamba training is completely separate. Having your pesticide applicator license does not qualify you to apply RUP dicamba in 2018.
Third, some have asked if everyone in the operation needs this training or not…specifically the person who is purchasing the RUP dicamba with his/her applicator license but is not the one intending on applying the chemical. NDA says that, “Dicamba-specific training is only required for application of the product, not for purchase of the product.”
- You need to be a certified pesticide applicator to purchase the RUP dicamba products.
- You need to be a certified pesticide applicator and complete dicamba training to apply the RUP dicamba product. So hopefully that helps clarify who in your operations need this training.
Your options for RUP dicamba training include the following:
- Nebraska Extension online training course hosted by eXtension. See the link at : https://campus.extension.org/login/index.php (1.25-1.5 hours).
- Crop Production Clinics or Nebraska Crop Management Conference. Details at https://agronomy.unl.edu/cpc and https://agronomy.unl.edu/ncmc
- County-hosted training sessions at the option of local educators presenting the video which is the same as the online training (1.25-1.5 hours).
- RUP dicamba product (XtendiMax®, FeXapan™, and Engenia®) manufacturer sponsored training. Each manufacturer will advertise individually.
I took the online training so I could better answer your questions. The link to the UNL online dicamba training can be found at the http://pested.unl.edu site or you can go directly to the training at: https://campus.extension.org/login/index.php. Once at this site, you will need to create an account. You will then be sent a confirmation email and upon opening that, you will be logged in. From the course list choose “pest management”.
Then scroll and click on “Online Training for Dicamba Herbicide”.
You will then need to register for the training. It will ask you to add your Nebraska pesticide applicator number in a specific field as well. Your name and applicator number are required before you begin the training. You can then click on the first video followed by the first quiz. It keeps track if you completed the entire video or not before you can advance.
I felt the information was good overall and I appreciated the fact that they mentioned how corn dicamba applications also influenced the problems we saw in 2017. They also share quite a bit of research regarding volatility, conditions/timing of temperature inversions, dosage amounts and effects on yield. The quizzes are short and were fairly common sense. You can click to check each answer once you have selected your choice and will have to submit all your answers before moving on. When you have completed all the videos and quizzes, you can have a certificate emailed to you. You will also be officially entered into Nebraska Department of Ag’s database. NDA said they will only honor those names in their database as those who’ve completed dicamba training.
NDA is asking ag retailers selling these RUP dicamba products to check the NDA database to ensure the person applying the product has received dicamba training. NDA’s dicamba information including record keeping forms, etc. can be found at: http://www.nda.nebraska.gov/pesticide/dicamba.html.
The other thing you need to know: some have asked if a group of people can watch the online training at the same time at your farmstead. The answer is actually no from the standpoint you all would have to watch the training on separate computers/devices. The only way your name is recorded in the NDA database is through your registration name and pesticide applicator number on the training site. It only allows one person to enter his/her information to view the training and complete the quizzes. If you attend an NDA approved face-to-face training such as at Crop Production Clinics, you can train as a group but will still need to supply your individual names and pesticide applicator numbers at the training.
Hopefully this helps clarify some of the questions you have and during this cold weather, you have the opportunity to get this training completed if you need it for 2018.
Reminder: York Ag Expo at the Holthus Convention Center in York January 10-11. Schedule of Events and Exhibitors: http://yorkchamber.org/yorkagexpo/
Educational Sessions: https://jenreesources.com/2017/12/26/york-ag-expo-educational-sessions/
May 23: Corn is looking good for the most part with few major concerns yet. Some have commented on the yellow-looking corn. This is most likely due to cool, wet soils rather than any nutrient issues. There may be field-specific issues such as saturated soils, compaction, and some herbicides that can cause this yellowing too. Also had a call on cutworms in seed corn but not widespread calls on this yet. Extension Educators have set up light traps for tracking cutworm moths and you can find that information here: http://go.unl.edu/rhhe. Cutworms will cause the most damage the first 7 days after corn emergence so scouting is important. The York County Corn Grower Plot was planted on April 24th with the corn currently at 2 leaf stage. Special thanks to Ron, Ray, and Brad Makovicka for hosting and the work put into this plot each year!
May 1: It never ceases to amaze me how quickly planting occurs each year! Corn planted the week of April 10th has emerged and for those fields that received hail from last week’s storms, I’m hoping we don’t see disease issues later on. Also of note, some have asked me about the CropWatch soil temperatures as they are higher than what some of you have been measuring in your fields before planting. The CropWatch soil temps at http://cropwatch.unl.edu/cropwatchsoiltemperature are averages of 24 hours under bare soil which may be different than the residue conditions in your fields and is an average of the entire day vs. one point in time. This may help explain some of the differences.
Many stands of alfalfa are lush green with over a foot of growth at this point. I looked at some alfalfa in Clay County that got dinged by cold temperatures in areas of the field and stopped growing. At this time I’m also finding quite a few aphids and a few alfalfa weevils. A disease common this time of year called spring black stem can be observed in nearly all alfalfa fields right now in the lower canopies. This disease consists of small black lesions on the leaves which eventually cause the leaves to turn yellow and drop. Normally this disappears with later cuttings as humidity and rainfall are typically high during the first cutting and can be managed with cutting the alfalfa. One option to consider according to Dr. Bruce Anderson, our Extension Forage Specialist, is to consider cutting alfalfa before bloom. He shares that weather can cause long delays and alfalfa doesn’t bloom very aggressively during spring. Bruce felt there were advantages to cutting alfalfa when it is 15-20” tall before bloom during first cutting including: weather compared to later spring, spread out alfalfa harvest if you consider cutting one field earlier, reduction in insect and disease problems by early harvest, and high feed value. It also potentially allows the second cutting to be ready before the summer heat which can lower forage quality. Disadvantages include lower yield from cutting early which could be made up in later harvest, regrowth may be slower if cut early, and the need to allow for longer recovery after first or second cutting to maintain long-term stands. So, harvesting before bloom may be something you wish to test in one of your fields this year and consider how this works for you, especially if you did have some frost damage or are having insect/disease issues in your alfalfa right now.
The field assessment workshops in Nebraska are hands-on and will show growers how to document eight sustainability and efficiency indicators via use of a laptop computer. The indicators are:
- land use,
- soil carbon,
- irrigation water use,
- water quality,
- energy use,
- greenhouse gas emissions, and
- water quality.
Computer laptops are provided or participants can bring your own. No prior computer knowledge is necessary and experienced users will be available to provide assistance.
Please contact the Extension Educator listed for each site to preregister by Dec. 3.
Monday, December 7, 9 a.m. – 1 p.m.
UNL Extension Office in Lancaster County, 444 Cherrycreek Road
Contact: Tyler Williams, (402) 441-7180 or firstname.lastname@example.org
Monday, December 7, 5:30 – 9 p.m.
UNL Extension Office in Gage County, 1115 West Scott St.
Contact: Paul Hay, (402) 223-1384 or email@example.com
Tuesday, December 8, 9 a.m. – 1 p.m. Nemaha County Hospital Meeting Room, 2022 13th St.
Contact: Gary Lesoing, (402) 274-4755 or firstname.lastname@example.org
Tuesday, Dec. 8, 5:30 – 9 p.m. UNL Extension Office in Fillmore County, 1340 G St.
Contact: Brandy VanDeWalle, (402) 759-3712 or email@example.com
Wednesday, Dec. 9, 9 a.m. – 1 p.m.
UNL Extension Office in Clay County, 111 West Fairfield Contact: Jennifer Rees, (402) 762-3644 or firstname.lastname@example.org
Wednesday, Dec. 9, 5:30 – 9 p.m.
UNL Extension Office in Merrick County, 1510 18th St.
Contact: Troy Ingram, (308) 946-3843 or email@example.com
Thursday, Dec. 10, 9 a.m. – 1 p.m. UNL Extension Office in Dodge County, 1206 West 23rd St.
Contact: Nathan Mueller, (402) 727-2775 or firstname.lastname@example.org
Friday, Dec. 11, 9 a.m. – 1 p.m.
UNL Extension Office in Saunders County, 1071 County Road G
Contact: Keith Glewen, (402) 624-8030 or email@example.com
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.
It’s nice seeing cattle being turned out into corn stalks! One point that I haven’t mentioned recently is that we all need to be checking the herbicide label for any grazing restrictions of crop residues.
So check the labels from in-season applied herbicides to row crops and fall-applied herbicides to crop residue for any potential grazing restrictions…and any restrictions on grazing cover crops planted into crop residues following application of those chemicals to a row crop. If the label doesn’t specify any restrictions, then it should be ok. If you want to be on the safe side, a rule of thumb many chemical reps use is to use the pre-harvest interval for the amount of time to wait before grazing stalks.
Some labels will say that residue should not be grazed or baled and fed to livestock. Sometimes studies were actually conducted to know there is a safety concern. In other cases, the chemical company may not choose to conduct all the studies the Environmental Protection Agency (EPA) required for labeling due to high costs. If that’s the case, the EPA requires the strongest restrictive language be placed on the label.
Regardless, if it says there’s a grazing restriction on the label, the label needs to be followed as it is a legal document and the law. Your cattle may/may not be affected by grazing stalks or cover crops where a chemical with a grazing restriction is on the label, but there may be other concerns such as problems with the chemical affecting the calf or being retained in the cow’s milk.
For quick references, the 2015 UNL Guide for Weed Management shows Forage, Feed, Grazing Restrictions for Row Crop Herbicides on pages 174-177. A new weed guide will be released January 2016. These pages just provide a reference; it’s truly best to read and follow the label.