Blog Archives
High Heat & #Corn Pollination
With the high heat, lack of rainfall, and pollination occurring in many fields or just around the corner, questions have been 
rolling in regarding how high heat affects corn pollination. Dr. Tom Hoegemeyer, UNL Agronomy Professor of Practice wrote the following article and I’m sharing it for the excellent info. Hybrid Maize simulations will be shared in this week’s CropWatch and in next week’s news article.
“Corn was originally a tropical grass from the high elevation areas of central Mexico about 7,400 feet above sea level, 2,000 feet higher than Denver. Today, corn still prefers conditions typical of that area — warm daytime temperatures and cool nights. Areas that consistently produce high corn yields share some significant characteristics. These areas — central Chile, the west slope of Colorado, etc. — are usually very bright, clear, high light intensity areas with cool nights.
This year, in the prairie states and in the Cornbelt, conditions have been dramatically less than optimal. Corn maximizes its growth rate at 86°F. Days with temperatures hotter than that cause stress. In the high yield areas, cool night temperatures — at or below 50°F — reduce respiration rates and preserve plant sugars, which can be used for growth or reproduction, or stored for yield. These are optimum conditions for corn, and interestingly, are fairly typical for areas around central Mexico where corn is native.
In years when we get high day and nighttime temperatures coinciding with the peak pollination period, we can expect problems. Continual heat exposure before and during pollination worsens the response. Daytime temperatures have consistently stayed in the upper 90s to low 100s.The high humidity, which helps reduce crop water demand, also increases the thermal mass of the air—and provides extra stored heat and insulation at night.
Corn pollen is produced within anther sacs in the anther. The plant releases new, fresh anthers each morning, starting from near the top of the tassel, on the first day of shed, and proceeding downward over several days. The process of releasing the pollen from the anthers is called “dehiscence.” Dehiscence is triggered by the drop in humidity, as the temperature rises. However, when it is extremely humid and the humidity falls very little, dehiscence may not occur at all, or it may be delayed until late in the day. If one has breezes, while the humidity is still very high, the anthers may fall to the ground before pollen is released. If the temperature rises too high before pollen dehiscence occurs, the pollen may have reduced viability when it is shed. A person experienced at hand pollination in corn will often see this happen. There will be anthers in a “tassel bag,” but little pollen. The usual solution to this is to wait a couple hours until the temperature rise reduces the humidity. However, last year we had some conditions where pollen was never released from the anthers. This can impact silk fertilization, particularly in open-pollinated situations.
Corn is a “C4 Photosynthesis” plant, making it extremely efficient at capturing light and fixing CO2 into sugars. One drawback of this system is that with high daytime temperatures, the efficiency of photosynthesis decreases, so the plant makes less sugar to use or store. High nighttime temperatures increase the respiration rate of the plant, causing it to use up or waste sugars for growth and development. This results in the plant making less sugar but using up more than it would during cooler temperatures. Heat, especially combined with lack of water, has devastating effects on silking. If plants are slow to silk, the bulk of the pollen may already be shed and gone. Modern hybrids have vastly improved “ASI” or anthesis-silk interval (the time between mid-pollen shed and mid silk). Regardless, in some dryland fields we see seed set problems because of “nick” problems between pollen and silking.
Even in some stressed areas within irrigated fields (extreme sandy spots, hard pans or compaction areas where water isn’t absorbed and held, and some “wet spots”) we can see stress-induced slow silking and resulting seed set issues. Historically, this has been the most important problem leading to yield reduction, particularly in stressful years. Once silks begin to desiccate, they lose their capacity for pollen tube growth and fertilization.
Even with adequate moisture and timely silking, heat alone can desiccate silks so that they become non-receptive to pollen. This is a bigger problem when humidity is low and on hybrids that silk quite early relative to pollen shed. Even with dew points in the 70s, when temperatures reach the high 90s to the100s, the heat can still desiccate silks and reduce silk fertility.
Heat also affects pollen production and viability. First, heat over 95°F depresses pollen production. Continuous heat, over several days before and during pollen-shed, results in only a fraction of normal pollen being formed, probably because of the reduced sugar available. In addition, heat reduces the period of pollen viability to a couple hours (or even less). While there is normally a surplus of pollen, heat can reduce the fertility and amount available for fertilization of silks. Research has shown that prolonged exposure to temperatures reduced the volume of pollen shed and dramatically reduced its viability. For each kernel of grain to be produced, one silk needs to be fertilized by one pollen grain.”
#Crop Update
While every growing season is unique and there’s an element of risk involved, this year seems to take the cake. 
Drought conditions have affected much of Nebraska. In our area in south-central Nebraska particularly in our southern tier of counties, we’re seeing brown pastures and alfalfa that stopped growing. Wheat was harvested nearly a month early and yields range from 0-50 bu/acre depending on if it was hit by the hail storm Memorial Day weekend which totaled it out.
I’m unsure how many planting dates we currently have in Clay County! The spring planting season went so well with corn and many beans being planted in April. Soybeans planted in April that haven’t received hail are forming a nice canopy. Corn that hasn’t received hail should be tasseling by beginning of July. One Clay Co. field planted in March was only 3 leaves from tasseling when I took this picture this week and looks great (it’s probably 2 leaves by now!). 
Adding another picture from a farmer friend Bob Huttes near Sprague, NE showing his field currently tasseled out and love the smiley face barn 🙂
But then there’s the hail damaged fields. The hail pattern has been fairly similar all year for this area of the State with some producers receiving four consecutive hail events on their fields. Every week of May was spent helping our producers determine replant decisions, particularly for soybeans…leaving irrigated stands of 85K and dryland stands of 60-65K when beans were smaller before stem bruising was so severe later. We would leave a stand one week and end up needed to replant after the hail hit again the following week. Some farmers got through the first two hail storms but the Memorial Day weekend storm did them in. I never saw hail like where ground zero of this storm occurred. After replanting after that weekend, they received yet another hail storm last week with the wonderful, much needed deluge of rain we received in the county. My heart hurts for these farmers yet for the most part they have good attitudes and are making the most of it. That’s the way farming is…lots of risk, thus an abundance of faith and prayer is necessary too. One farmer I talked to has had hail on his house seven times this year (including prior to planting).
Pivots have also been running like crazy prior to the rain last Thursday night where we received 3.30-4.40 inches in the county. Installing watermark sensors for irrigation scheduling, we were able to show the farmers that there was truly moisture deeper in the soil profile and attempted to convince them to hold off. It’s a hard thing to hold off on 
water when the neighbors are irrigating, but several farmers who didn’t irrigate told me they were able to let the rain soak in and their plants 
weren’t leaning after that rain because the ground wasn’t saturated prior to the rain event.
Crop Water Use Comparison Study
Water use efficiency (or crop water productivity) is important in crop production. The seed Industry has invested scientific 
efforts and financial resources into developing hybrids and varieties that can better tolerate environmental stresses such as water stress.
Rainfed corn has increased in acres, replacing sorghum year after year. This trend may be partly due to the basis price, herbicide options, and newer corn hybrids bred with root systems to better withstand water stress. In 2009 the question was posed, “Is sorghum still the most crop-water-use-efficient crop, given newer corn hybrids in rainfed fields are providing decent yields and more herbicide options?” To answer the question the Nebraska Grain Sorghum Board funded a project in south-central Nebraska.
On-farm research was conducted for three years in rainfed production fields near Lawrence with the most adapted and high-yielding corn, sorghum, and soybean hybrids and varieties for that area. The research was conducted in no-till fields where the previous crop had been sorghum. A randomized complete block design with three replications was used.
Corn and soybean were planted between May 5 and May 7; sorghum planting ranged from May 19 to May 28. Corn was planted at 20,000 seeds/acre, soybean at 135,000, and sorghum at 65,000. Rainfall in this area varied greatly from 2009 to 2011: 2009 was dry with only 10 inches of rain during the growing season; 2010 had 16 inches, and 2011 had 20.5 inches from May 1 to October 15.
To monitor soil moisture, Watermark sensors were placed at 1-, 2-, 3-, and 4-foot depths in each plot and the readings were 
recorded hourly throughout the growing season via Watermark dataloggers. Data were compiled and analyzed to determine crop water use efficiency (CWUE) values. The CWUE values were determined from the Watermark soil moisture data, actual crop water use (evapotranspiration), and grain yield for each crop.
Results: Table 1 shows actual crop evapotranspiration (ET) in inches, grain yield, and crop water use efficiency for each crop in each year. Corn was the most water use efficient of the three in 2009. Sorghum results in 2009 might have been different if rainfall had occurred to activate the sorghum herbicide as grass pressure was heavy in the sorghum plots that dry year. In 2010-2011, sorghum yielded the most, had good weed control, and had the best crop water use efficiency value.
| Table 1. Crop water use efficiencies in on-farm field trials conducted near Lawrence, Nebraska, 2009-2011. | |||||||||
| 2011 ET (in) |
2011 Yield (bu/ac) |
2011 CWUE (bu/in) |
2010 ET (in) |
2010 Yield (bu/ac) |
2010 CWUE (bu/in) |
2009 ET (in) |
2009 Yield (bu/ac) |
2009 CWUE (bu/in) |
|
| Corn | 22.0 | 127.2 | 5.8 | 23.3 | 101.2 | 4.3 | 14.5 | 97.5 | 6.7 |
| Soybean | 21.3 | 61.3 | 2.9 | 22.0 | 44.0 | 2.0 | 14 | 33.4 | 2.4 |
| Sorghum | 17.3 | 138.9 | 8.0 | 21.3 | 118.0 | 5.5 | 13.7 | 77.4 | 5.6 |
Overall in this study, sorghum had a crop water use efficiency of at least 5.5 bu/inch; corn, at least 4.3 bu/inch, and soybean, at
least 2.0 bu/inch. These results show sorghum’s continued value as a crop that efficiently uses water. Sorghum produced more grain per unit of water used than corn or soybean, an important benefit in water-limited environments. On a three-year average, sorghum resulted in 1.2 bu/inch and 3.5 bu/inch more grain production per inch of water used than corn and soybean, respectively. This study did not compare sorghum or soybean with new “drought-tolerant” corn hybrids. Graphs, charts, and production information can be found here.
Acknowledgements: Special thanks to John Dolnicek of Lawrence, Nebraska for allowing this research to be conducted on his farm and for all his help and efforts to make it a successful study and to the Nebraska Grain Sorghum Board for funding this study.
Soil Crusting in #Soybeans Causing Concerns
On May 6, quite a storm was unleashed in south central Nebraska. Soybeans that had been planted two to three days before the
storm seem to have emerged fine, while those planted May 5-6 tend to have uneven emergence and crusting. This is occurring regardless of tillage type, residue cover, etc. Many farmers have been running pivots to help the soybeans break through the ½- to 2-inch crust, often applying an inch of water before they see stand improvements.
The primary question for growers has been “Should I replant?”
UNL on-farm research has shown less than 1.4-2.0 bu/ac yield difference between planting 90,000 and 180,000 seeds/acre. (See report.) In our research, 90% of the planted stand was achieved at both seeding rates in irrigated 30-inch rows in no-till and ridge-till fields.
Consider what was found in 2006 in one dryland field in Nuckolls County where populations of 100,000, 130,000, and 160,000 seeds/acre were planted. This field was at the cotyledon stage when it was hailed. Some plant stands dropped to 67,000. Yield was 4 bu/ac less than in the 160,000 seed/acre planting that had a final stand of nearly 98,000. The average yield in the field was 40 bu/ac. While this is only one field and one year of research, it is an example of how soybean plants can compensate for reduced populations by branching and how August rains in dryland can still allow reasonable yields to be produced.
UNL research conducted by Dr. Jim Specht, UNL Soybean Physiologist, also has shown that for every day planting is delayed after May 1, there is the potential to lose 1/4 to 5/8 bushel per day. As we near the end of May and early June and consider that late planting yield penalty and the dry soil conditions (particularly in dryland fields), along with the seeding rate results from this UNL on-farm research, we are recommending that growers leave stands in many fields. Based on our on-farm research, leaving dryland stands of at least 65,000 plants/acre and irrigated stands of 90,000 plants/acre is likely a better choice than replanting.
We realize that there are some larger gaps in various rows in the field, and while we don’t like to see that, the gaps are disappearing as plants continue to grow and branch out. Keep in mind that a gap in one plant row will be compensated by plants in the adjacent flanking rows. They will form extra branches to take advantage of the sunlight, thus single-row gaps may not be as yield-reducing as you might think — especially in 15-inch row spacings.
We’re also seeing how resilient soybeans are. Some soybeans have been in the ground for two weeks and in many cases, are fairly healthy below the crust. Soybean seedlings emerge by pulling (not pushing) their cotyledons upward. The seedlings rely on the cotyledons as a reserve source of carbohydrate, protein, and lipid to support early seedling development until leaflets open for photosynthesis. When a seedling tries to pull its cotyledons through a crack in the crust, the crack may be too small and the cotyledons may be stripped off.
The plumule, which is the seedling stem tip and its undeveloped leaves above the cotyledonary node, may remain, but 
without the cotyledons to serve as a carbon and nitrogen source, development of new seedlings with small leaflets will be slow. These plants may not become competitive with surrounding plants in terms of pod and seed production. Therefore, when counting seedlings to determine plant stand after a soil crusting event, count only the seedlings that have at least one cotyledon. You can count seedlings missing cotyledons if they have large unifoliolate leaves that will soon unroll such as the picture on this page.
Recommendation: When deciding whether to replant your field, consider UNL research findings that showed a minimal yield difference between stands of 90,000 and 180,000 seeds/acre. We recommend leaving irrigated soybean plant stands of 90,000 or more and dryland plant stands of 65,000 or more. Uniformity of plant stands is also important, but “patch” planting may be used to deal with local areas of low plant stands.
For more information on reduced soybean planting rates, see the April 20, 2012 CropWatch story, Drop Soybean Seeding Rate and Save $10-$18 per Acre.
Future of Rural America
Sunsets over rolling hills of green pastures and straight corn rows. Barely seeing above soybeans I was walking to remove 
weeds. Attending a small school that provided an excellent education with opportunities to participate in a variety of activities to become more well-rounded. These are a few of numerous memories of growing up on the farm and in a rural community that I hold dear. While I enjoy hearing my grandparent’s stories of what life was like for them farming 60 years ago and even enjoy watching the Nebraska State Cornhusking Contests held each year, I also realize times have changed and don’t have a false sense of nostalgia about what rural means today. While technological advances allow our farmers to produce more food for more people with less inputs and less water than ever before, what hasn’t changed about rural communities is the hard work ethic, dedication, risk, determination, and reliance on Faith and family to get through each year.
Last week I had the opportunity to participate in the Rural Futures Conference held in Lincoln. For me, it was the best conference I’ve attended; the energy and enthusiasm from 450 people gathering from a variety of backgrounds all to discuss the future of rural America was refreshing to say the least. My favorite part of the conference was the first evening. The key note speaker Joel Sartore, a Nebraska native who is also a National Geographic photographer, challenged us to maintain a positive attitude and to look for the opportunities that were available in our small towns. For example, one town in Kansas was all about a certain sparrow where they would take people out on field trips to “listen”-they didn’t even get to “see” the sparrow-and people paid money for that! There was also a town in Oklahoma where all they had was rattlesnakes…so they made the most of that too and created a huge attraction around snake handling, pics with snakes, snake skinning, etc.
My favorite part of the conference occurred after that during the youth panel. A panel discussion with Caleb Pollard, 
Executive Director of Valley Co. Economic Development in Ord, NE; Amanda Crook, Graduate Student; Anne Trumble, Executive Director of Emerging Terrain in Omaha; Jim McClurg, University of Nebraska Board of Regents; and University of Nebraska Med Center’s Bob Bartee answered questions moderated by Dr. Ronnie Green, IANR Vice Chancellor. The young people struck a chord with me-most likely cause we were of similar age. Some key take-away quotes:
- Vibrant organizations identify strong leadership.
- Failure can be a good thing as it can lead to the next innovation.
- To go some place and change the trajectory of history is exciting!
- We need to change the way we place young people into jobs….we don’t offer young people jobs; we offer them opportunities.
These young people were so excited about living in Nebraska! Some of them had spent time elsewhere before choosing to move back to Nebraska and eventually choosing to find a small town to raise their families or have the rural way of life. Another theme that emerged throughout the conference was the need to get young people involved in the local community such as youth representatives on city council, etc. even as early as when they’re in high school. Some people think small town communities in Nebraska are dead…but that’s not necessarily the case. It mostly depends on leadership-a strong leader will rally the town around an idea to grow it or create opportunities. That’s what’s happening in Ord, NE with Caleb Pollard. Another example comes from Fairfield Iowa. Sometimes it just takes the right person to ignite a spark and help the rest of the town see the possibilities. Nebraska has so much to offer!
Frans Johansson, author of The Medici Effect, was also a phenomenal speaker! He spoke about creating breakthrough innovations by thinking outside the box and working at intersections of different disciplines/cultures, etc. Key points I obtained from him include:
- New ideas are combinations of existing ideas.
- People who change the world try FAR more ideas.
- Diverse teams can unleash an explosion of new ideas.
- Find inspiration from fields/cultures other than our own.
- Look for the smallest executable step-essentially don’t eat the elephant in one bite.
- Stepping into intersections isn’t risky-it’s risky to do the same thing over and over again.
Maybe these aren’t earth-shattering new concepts, but good reminders for a task as large as creating a Rural Futures Institute…and frankly for anything in life.
There was much discussion about the role of a University/State/Community Colleges in trying to save rural communities…how is this done…how build partnerships and trust…how to provide incentives to faculty working in creative/innovative ways in a structured academic setting when it comes to promotion and tenure…and even if the University changed its incentives, how does that bode if a faculty member moved on to another University? How are incentives provided to teams and excellent team work? We are standing at the crossroads…maybe an intersection right now in academia which can shape the future of creatively rewarding innovative work while still maintaining needed structure in the promotion/tenure process. I remain positive that we’ll find a way to work through this!
There were discussions in small groups regarding the meaning of rural. What does it entail? Often we think of agriculture-and I would argue that’s a strong part of rural-but it’s also much more…health care, infrastructure, industry, schools, broadband, etc. Some were saying we need to use the term non-metro instead of rural in order to get away from the ag connotation. Yet others felt the discussion was too focused away from agriculture on other components of rural and missing ag as a key component. Needless to say, the entire conference provided interesting discussion, dialogue, and a chance to meet people from a variety of backgrounds. It truly provided an opportunity to look for intersections with which to create innovative ideas for the future.
There was also the reality that hit during focused group conversations that there are also problems that need to be addressed in rural communities that weren’t touched on at this point: poverty; crime; infrastructure; food deserts; building trust and interfacing with university, college, and other partners, etc. Overall it was a thought-provoking conference and has the feel that several small steps can be achieved in the coming year. I would encourage you to check out the Web page and follow the Facebook page. You can also check out the Twitter Conversation at #RFC2012. This conference was also not just focused on Nebraska as the focus was the Great Plains and people from numerous states attended. I’m looking forward to seeing the small executable steps that will occur in the future and am also looking forward to doing my part to maintain strong rural communities as I’d like to see the next generation enjoy the rural life and learn the values I did growing up!
The Season for #ag & #horticulture Questions!
This past week was a blur of calls, questions, and visits to homes and fields but it was a great week and flew by staying very busy! I’ll touch on a few of the common questions I’ve received this week.
Trees: Some trees such as willows, hackberries, tops of maple trees, ash, and black walnut are just taking time leafing out. Some trees leafed out once already and dropped leaves. Things that may have caused this were the sudden flux of temperatures from very warm to cool and the strong winds we received. Some trees have also unfortunately had herbicide drift damage that caused leaves to drop. On those trees, watch for new buds as nearly every situation I’ve looked at thus far have new buds forming after about a week-10 days. With all these situations, give the trees a few weeks to leaf out again and if they’re still not doing it, feel free to give me a call. Trees are interesting plants as sometimes environmental impacts that happened 3-5 years ago will show up that much later-and sometimes environmental impacts show up right away!
Disease/Insect issues: This year has been a strange year all around but with our warm winter, I was concerned about an increase in diseases and insects. Thus far, we’re experiencing increases in both-so hang on-it may be a long growing season! Our high humidity, warm temps, and heavy dews have created perfect conditions for fungal diseases on our trees, ornamental plants, lawns (I’m currently fighting a bad case of powdery mildew-as a plant pathologist it is kind of pretty but I don’t like what it’s doing to my lawn!), and in our wheat and alfalfa crops and some pasture grasses. Fungicides may help in some of these situations, increasing airflow can also help as can more resistant varieties or hoping the weather will change. In the case of most ornamentals, we don’t usually recommend doing anything. The same goes for insects as insecticides can help in some situations. I’ve received several calls this past week of people afraid they had herbicide drift damage. While there were a few cases of that, many of the cases were actually fungal leaf spots on leaves. There are various fungicides and insecticide products available from home/garden centers, etc. Be sure to read and follow all label directions and only apply the product on places the label specifies it can be applied.
Crops Update: Later this week we may have a better idea on the extent of storm damage and if some fields will need to be 
replanted after the storms from last week. Dr. Bob Nielsen from Purdue University reported that most agronomists believe young corn can survive up to about four days of ponding if temperatures are relatively cool (mid-60’s F or cooler); fewer days if temperatures are warm (mid-70’s F or warmer). Soil oxygen is depleted within about 48 hours of saturation and we know soil oxygen is important for the root system and all the plant’s life functions. So we’ll have to wait and see what happens.
Have also had a few calls regarding rye cover crops. When rye is killed out and decomposing, it releases toxins that can affect the germination of other cereal crops such as corn if it’s going to be planted into that rye cover crop. Thus we recommend at UNL that the producer kill the rye and then wait at least two weeks to prevent any major damage to the crop. I realize at this point with the rains to get in and kill that crop on top of waiting an additional two weeks, we’re getting close to the end of the month and will most likely be looking at reduced yields…and depending on maturity, you may need to consider different seed if you end up having to plant in June. If you have specific questions about this, please let me know and we can talk through some situations.
Stripe rust and powdery mildew have been obliterating mid-lower canopies of many wheat fields. I’ve received several calls
on why wheat canopies are yellow-that’s the main reason but other factors such as the dry spell prior to these rains and/or deficiencies in nitrogen/sulfur or some viruses may also have been factors. Wheat in Nuckolls County last week was beginning to flower. Fungicides such as Prosaro, Folicur, or Proline are labeled for up to 50% flowering and cannot be applied after that. Remember the wheat head begins pollination in the middle-so if you’re seeing little yellow anthers at the top or bottom of that head, you’re towards the end of flowering. All those products have a 30 day pre-harvest interval-which has been the other main question-are we going to be harvesting in a month? I do believe we’ll be harvesting a month earlier than normal just because pretty much everything in wheat development is about a month ahead of schedule. I still feel the 30 day window for the fungicide application is worth it with the large amount of disease pressure we’ve seen. Wheat in Clay Co. and north still may have time for a fungicide application; those products mentioned above will help prevent Fusarium Head Blight (scab) as well as kill the fungi causing disease already present on your leaves. A list of all fungicide products, pre-harvest restrictions, and rates can be found here. Also check out my previous blog post with video on scouting for wheat diseases.
The other major disease appearing in wheat is barley yellow dwarf virus. This is a virus vectored by bird cherry oat aphids which we were seeing earlier this year. Unfortunately, this disease causes the flag leaves to turn bright yellow-purple causing yield loss (at least 80% of the yield comes from the flag leaf) as there’s nothing you can do once the virus manifests itself in those leaves. If you have a large incidence of barley yellow dwarf in your fields, you may wish to reconsider spraying a fungicide as the fungicide won’t kill the virus; however, it will help kill the fungi on the remainder of your leaves and potentially help protect some yield from the two leaves below the flag leaf.
Drop #Soybean Seeding Rate & Save $
Increasing input costs are forcing producers to evaluate every decision they make. With soybean seed costs on the rise, producers in the Greater Quad County On-Farm Research group wondered if they could reduce their soybean populations while maintaining yield and saving money. On-farm research conducted in field scale, randomized, and replicated farmer plots and at the South Central Agricultural Laboratory near Clay Center from 2006-2008 proved producers could.
Since 2006, planting rates of 90,000, 120,000, 150,000, and 180,000 seeds per acre have been planted in 12 irrigated soybean fields on 30-inch rows. Prior to this research, most of these producers usually planted 160,000-180,000 seeds/acre. The 90,000 low rate was determined based on UNL research recommending not to replant a hailed soybean stand if at least 90,000 plants/acre remained in the field.
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In 2008, cooperating producers used these same rates to plant soybeans at five sites with 20 replications. Planting dates ranged from April 29 to June 3. In the end, there was little difference in percentage stand and yield among the four planting rates (see Table 1). The 120,000, 150,000, and 180,000 yields were statistically the same (only a 0.3-bushel difference between the 120,000 and 150,000 rates) and were significantly better than the 90,000 seed-per-acre plots; however, note that the 90,000 plot yielded only 1.7 bu/ac less than 150,000 plot. All data was statistically analyzed to determine the yield differences due to the various treatments.
The findings are similar to the 2006 and 2007 studies. In 2006, yield results ranged from 65.5 bu/ac at 90,000 to 67.4 bu/ac at 180,000. In 2007 yield results were 59.4, 59.6, 59.4, and 60.2 bu/ac for 90,000, 120,000, 150,000, and 150,000 respectively with no statistical difference.
Most likely, these results are indicative of soybean’s ability to compensate for reduced populations. Figure 1 shows increased plant branching at lower populations compared to less branching at higher populations. This was observed in all fields regardless of variety. Also observed in 2008, were two additional nodes/plant at the 90,000 population compared to the 180,000 population. Nodes are important as flowers, pods, and ultimately yield are produced from them.
A dryland field in Nuckolls County also showed interesting results. This field was hailed at the cotyledon stage, so planted populations of 100K, 130K, and 160K became average actual stands of 74,417; 89,417; and 97,917 plants per acre. August rains in 2006 helped deliver yields of 38.6, 40.6 and 42.7 bu/ac, respectively.
Figure 1a. Lower planted populations of 120,000 compensated for reduced plants by increased branching, flowering, and pod set, regardless of typical variety architecture.
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Figure 1b. Fields with planted populations of 150,000 were observed having a more erect architecture with reduced branching compared to fields planted at rates of 120,000. |
Rates for Drilled Soybean:
In 2006, one drilled field in irrigated conditions in Fillmore County yielded 68.4 bu/ac, 66.6 bu/ac, and 67.2 bu/ac for planting rates of 150,000, 175,000, and 190,000 seeds per acre respectively. Another study in 2006 conducted by the Soybean Feed Grains and Profitability Project in a rain-fed field in Lancaster County showed a slight but significant yield advantage to drilling soybean at a rate of 152,500 seeds per acre compared to 115,000 seeds per acre. Yield for the higher seeding rate was 56.8 bu/ac compared to 56.0 bu/ac with the lower seeding rate. When using grain drills and reducing soybean populations, variable seed spacing and seed depth within a drilled row can be an issue for soybean emergence. This is why a population increase for drilled beans is often recommended.
Recommendation: Plant Soybeans at 120,000 Seeds/Acre
Based on three years of consistent research results, UNL specialists recommend reducing planting populations from an average of 160,000 seeds/acre to 120,000 seeds/acre in 30-inch rows. This reduction of 40,000 seeds per acre results in a savings of $10.66 to $18.57 per acre based on seed costs of $40-65 a bag. For three years producers were able to achieve a 90% stand and have not seen a statistical yield variance from 150,000 or even 180,000 seeds/acre. With soybean seed costs increasing, reducing soybean planting populations is another way producers can survive high input costs of crop production.
Plant #Soybeans Early for Increased Yields
While I got this posted in our CropWatch Web site, I didn’t get it on my blog till now! Hopefully this inspires many of you to get soybeans planted yet this week! 
Planters are rolling throughout the state and given the size of today’s equipment corn planting is rapidly progressing. Based on UNL research, we would encourage you to consider planting your soybeans as soon as possible—preferably before the end of April for the southern two-thirds of Nebraska and or the first week of May for the northern third of Nebraska. While evening temperatures have been low, consider the percent risk of frost for emerged plants not planted seeds. The above recommendation considers a 10% risk of frost 7-10 days after planting, the time when soybeans would most likely emerge.
Why plant early? Five years of UNL small plot and on-farm research has proven that early planted soybeans yield more than late planted beans—regardless of whether the spring has been cold and wet or warm and dry. Soybeans are a photoperiod-sensitive crop so the goal is to allow the plant to use the sun’s energy to accumulate as many nodes as possible as day length decreases after June 21. Nodes are important because that’s where pods, seeds, and ultimately yield are produced. The goal is to have the soybean canopy “green to the eye by the fourth of July!”. Thus the plants are absorbing all the sunlight possible not allowing any to be wasted by hitting the soil.
Table 1 shows how three years of on-farm research have resulted in an average of 3 bu/ac yield increase (with a range of 1-10 bu/ac depending on the year and the planting date range of early versus later planting). With today’s soybean prices, a 3 bu/ac yield increase adds up (see Table 2). We do recommend a fungicide/insecticide seed treatment to reduce the risk of damping off diseases and bean leaf beetles which tend to feed on early-planted soybeans.
Several previous CropWatch articles explain soybean planting date in more detail. Please see these for more information:
- For Increased Yields Plant Soybeans in Next Two Weeks
- Three Reasons Why Soybean Planting Date Matters
- Farm Research Shows Benefits of Planting Soybeans Early
- Risks and Caveats of Early Planting Soybeans
Table 1: Nebraska On-farm Research Early and Late Planted Soybean Yield Results (2008-2010)
|
Year |
Producer |
Date |
Reps |
Rainfed/ Irrigated |
Variety |
Row Spacing |
Yield (bu/acre) |
|
2008 |
SCAL Early |
Apr. 29 |
3 |
Irrigated |
Producers 286 |
30” |
67.2 |
|
2008 |
SCAL Late |
May 15 |
3 |
Irrigated |
Producers 286 |
30” |
65.8 |
|
2008 |
Seward Co. Early |
Apr. 30 |
3 |
Irrigated |
NC+ 2895 |
30” |
68.4 |
|
2008 |
Seward Co. Late |
May 19 |
3 |
Irrigated |
NC+ 2895 |
30” |
66.2 |
|
2008 |
York Co. Early |
Apr. 23 |
8 |
Irrigated |
Producers 286 |
30” |
66.9 |
|
2008 |
York co. Late |
May 14 |
8 |
Irrigated |
Producers 286 |
30” |
63.5 |
|
2008 |
Fillmore Co. Early |
Apr. 30 |
7 |
Irrigated |
Pioneer 93M11 |
30” |
81.0 |
|
2008 |
Fillmore Co. Late |
May 19 |
7 |
Irrigated |
Pioneer 93M11 |
30” |
77.5 |
|
2009 |
SCAL Early |
Apr. 27 |
4 |
Rainfed |
Pioneer 93M11 |
30” |
37.6+ |
|
2009 |
SCAL Late |
May 18 |
4 |
Rainfed |
Pioneer 93M11 |
30” |
37.2 |
|
2009 |
Saunders Co. Early |
May 3 |
6 |
Rainfed |
NC+ A63RR |
15” |
66.6 |
|
2009 |
Saunders Co. Late |
May 21 |
6 |
Rainfed |
NC+ A63RR |
15” |
65.1 |
|
2009 |
SCAL Early |
Apr. 27 |
4 |
Irrigated |
Pioneer 93M11 |
30” |
70.2 |
|
2009 |
SCAL Late |
May 18 |
4 |
Irrigated |
Pioneer 93M11 |
30” |
68.1 |
|
2009 |
Fillmore Co. Early |
Apr. 24 |
4 |
Irrigated |
Pioneer 93M11 |
30” |
69.5 |
|
2009 |
Fillmore Co. Late |
May 15 |
4 |
Irrigated |
Pioneer 93M11 |
30” |
68.4 |
|
2009 |
Seward Co. Early |
Apr. 24 |
4 |
Irrigated |
NC+ 2A63 |
30” |
73.2 |
|
2009 |
Seward Co. Late |
May 20 |
4 |
Irrigated |
NC+ 2A63 |
30” |
71.3 |
|
2009 |
York Co. Early |
Apr. 30 |
3 |
Irrigated |
NK 28B4 |
30” |
59.1 |
|
2009 |
York Co. Late |
May 15 |
3 |
Irrigated |
NK 28B4 |
30” |
58.6 |
|
2010 |
Saunders Co. Early |
Apr. 18 |
6 |
Rainfed |
Channel 2751 |
15” |
75.7 |
|
2010 |
Saunders Co. Late |
May 18 |
6 |
Rainfed |
Channel 2751 |
15” |
71.2 |
|
2010 |
Seward Co. Early |
Apr. 19 |
6 |
Irrigated |
Channel 3051RR |
30” |
72.0 |
|
2010 |
Seward Co. Late |
May 24 |
6 |
Irrigated |
Channel 3051RR |
30” |
62.3 |
|
|
Average Early |
|
|
|
|
|
70.0* |
|
|
Average Late |
|
|
|
|
|
67.1 |
*Statistically significant at 95% level.
+SCAL Rainfed was not included in the combined statistical analysis but Saunders Co. Rainfed was compared with irrigated yields from other locations.
Table 3: Economic Advantage to a 3 bu/ac Yield Increase Due to Early Soybean Planting Date
| Price of Soybeans | $ 7.00 | $ 8.00 | $ 9.00 | $ 10.00 | $ 11.00 | $ 12.00 | $ 13.00 | $ 14.00 |
| Economic Advantage | $ 21.00 | $ 24.00 | $ 27.00 | $ 30.00 | $ 33.00 | $ 36.00 | $ 39.00 | $ 42.00 |
Protecting #Nebraska #Ag & #Farm Transition
A few weeks ago I shared some thoughts with you regarding what I learned from an animal welfare conference. We have an opportunity to hear more in at a much closer location-Sutton Community Center in Sutton-on March 12th at 6:00 p.m. Dewey Lienemann, UNL Extension Educator will be presenting on “Protecting Nebraska Agriculture” following a meal sponsored by the Sutton Chamber of Commerce Ag Committee as well as area Cattlemen Associations, Breeders & Feeders, and Ag Producer groups. Anyone interested is invited to attend-and I would encourage anyone who possibly can to attend. This topic not only affects livestock producers, it affects crop producers, and consumers as well. It’s very important to understand how various interest groups are attacking animal agriculture and why and how we in rural America can share our stories. Please pre-register by contacting Tory Duncan at (402) 773-5576 or ccntory@gmail.com or Todd Mau at (402) 773-5224 or todd@toddstrailers.com.
Another opportunity for learning more about family farm transition is with the last Farmers/Ranchers College program this year. It will be March 15 in Friend at the San Carlos Community Room (next to the Pour House) with meal beginning at 6:00 p.m. (Registration at 5:30 p.m.) The program entitled “Discussing the Undiscussabull” will be presented by Elaine Froese from Manitoba, Canada. Froese’s expertise in helping families get unstuck is sought after across the country. She has worked with families in business for over 20 years and is now coaching the next generation. Elaine believes that change is an opportunity, not a threat…she has practical tools to help people discuss the “undiscussabull” to make their dreams come true. In order to save your spot and reserve a meal, registration is needed by calling the Fillmore County Extension office at (402) 759-3712. The Farmers & Ranchers College is sponsored by area agribusiness, commodity groups in collaboration with the University of Nebraska-Lincoln Extension.
JenResources 