Blog Archives

Weed Science Field Day

Hope to see you at this weed science field day at UNL’s South Central Ag Lab near Clay Center on July 2nd! No charge.  Please RSVP to (402) 762-4403.  More information at:  http://scal.unl.edu.

WeedScienceFieldDay

Understanding Research Statistics

Dr. Charlie Wortmann, UNL Extension Soil Fertility Specialist, explains the power of statistics for understanding yield and other differences and non-differences for on-farm research.

Sugar Applications to Crops

For the past ten years I’ve come across farmers who really believed in applications of sugar to reduce their pest populations.  Being no research to my knowledge to prove it, I tucked the observation in the back of my head for future reference.  With farmers looking to increase yields and looking to other farmers such as Kip Cullers for information, some of our on-farm research producers were curious about sugar applications in their operations with the hopes of increasing yield.

Nebraska On-Farm Research Corn Results

Using the application rates that Kip Cullers uses, one Clay County producer applied 3 lbs of sugar (purchased pallet of cane or beet sugar from the local grocery store) per 10 gallons of water at V7-V8 on corn in 2010-2011.  Cullers also tanked mixed the sugar solution with a post-herbicide application like glyphosate but this producer didn’t do that.  To simulate any affect of the water or driving through the field, he also drove through the untreated check spraying water only.  Two  years of research results showed no significant increase in yield.  However, there was a noticeable difference in standability at harvest.  This producer did not apply a foliar fungicide either year.  When it came to harvest, this producer needed the reel in 2010 for the untreated check.  Stalk rot ratings were taken using the pinch test two weeks prior to harvest.  To him, the $1.25/acre of sugar was worth it to improve standability even if yield was not significantly improved.  You can view the full research report here.

2010-2011-SugarOnCorn On-Farm Research Clay County Nebraska

Several York County producers have also tried this with one producer finding a non-statistical 2 bu/ac yield difference with the check yielding better while the other producers found a statisically significant 2 bu/ac increase to the sugar treatment.  Another producer in Hamilton County is testing this using the corn product he grows-using 1 qt of corn sugar (high fructose corn syrup) per 10 gal of water applied still at V7-v8.

In 2012, a small plot study was conducted at UNL’s South Central Ag Lab near Clay Center to determine any differences between sugar application, fungicide application, and untreated check in corn.  All treatments were applied at R2.  Because of the drought in 2012, there was minimal disease pressure, thus there were no significant differences between the three treatments regarding area under the disease progress curve.  The untreated check did show the most stalk rot (via the push lodging test).  The sugar application reduced the lodging rating by half and the fungicide application showed the lowest lodging rating.  For yield, there were no significant yield differences with the untreated check yielding the highest followed by the fungicide and sugar applications.  The entire study report can be found here.

In Soybeans we have had producers apply 3 lbs sugar in 10 gallons of water at R3 (beginning pod).  In all years, there have been no significant differences in yield.  Lodging ratings were not taken as that is more variety and water dependent.

Additional research…

has shown that application of sugar to crops increases the numbers of beneficial insects in those fields.  South Dakota research entomologists showed that lady beetles benefited from a combination of prey and non-prey foods.   In a follow-up study, these entomologists applied sugar sprays to soybeans and quantified the frequency of sugar feeding by analyzing the gut contents of common lady beetles in three states.  They found all the tested lady beetles regularly consumed sugar-like nectar in soybean fields, even when it wasn’t applied as a supplement.  They also found more lady beetles in the sugar treated plots compared to the untreated plots.

At this time we can’t explain the standability effect we’re seeing from our sugar applications to corn.  Our hypothesis is that early application of sugar to corn is increasing beneficial microbes that may be keeping the exposed brace roots and stalks healthier.  We hope to conduct more research in the future to answer this question.

In conclusion,

the application of sugar to corn and soybeans has not always shown increased yield.  However, in nearly all of the corn studies, sugar treated plots have shown increased stalk strength at harvest.  Research has also shown an increase in the number of beneficial insects in fields where sugar was applied.  Further research is needed to understand the interactions aiding stalk strength in corn.

If you are interested in conducting on-farm research studies in your field, please contact any of our UNL Extension Educators or Specialists!  You can also follow the conversations this year via our Facebook page and Twitter feed!

What do you think of sugar applications to crops?  Have you tried this in the past and if so, what were your results?

Corn Planting Rate Research & Recs

Even with recent rain and snow events, the subsoil is still dry.  You may be wondering,

“What should I do regarding corn planting rates in 2013?”

A few weeks ago, UNL Extension held our on-farm research meetings to share our 2012 Corn Planting Rate results for irrigated and dryland conditions.  I always enjoy hearing our farmers share why they were interested in a certain trial and what they found out as a result.

Our farmers followed protocols of 28K, 32K, 36K, 40K (40,000 seeds/acre) or 30K, 34K, 38K, 42K/acre for irrigated production and 18K, 22K, 26K, and 30K for dryland production. 2012 Irrigated On-farm Corn Population Study-UNL

The results since 2010 continue to show us that each individual hybrid varies in its response to increasing populations; however, there is a general trend with newer hybrids that increasing population results in increased yields.  Dr. Tom Hoegemeyer, UNL Agronomy Professor of Practice spoke about how our hybrids have genetically come so far in combating various stresses while maintaining yields.  We know that many seed companies have conducted research to determine the population calibration curve for each hybrid to determine best recommendations for you.  Thus, we’d recommend that you check with your seed dealer to determine which hybrid may fit best at which population for your operation.

Even with this data, you may question if that’s truly the best population for your field; that’s where on-farm research comes in!  We recommend testing the recommended population against a higher and lower population with at least 4000 seeds/acre difference in planted population-whether irrigated or dryland.  With today’s technologies, it’s not very difficult to test seeding rates for different hybrids for yourself!

So what rate should you plant this year?  In the majority of our irrigated studies, economically, many hybrids maximized yields and economic returns between 32,000-36,0o0 seeds/acre.  Again, this is very hybrid dependent so ask your seed dealer what he/she would recommend and test for yourself!

Regarding limited irrigation, UNL research has actually shown a negative effect of lost yield by backing off population too far in a dry year. 2012 Dryland On-farm Research Corn Population Study-UNL

Tom’s recommendation was for dryland in Eastern Nebraska, most hybrids even with the low soil moisture profile should be ok with planting 24,000-28,000 seeds/acre.  I realize we have essentially no moisture in our profile.  But taking probabilities of rainfall events, March-May is usually pretty good and we don’t want to short-change ourselves in yield by planting too low of populations.  For Central into Western, NE, I feel 20,000-22,000 seeds/acre will work for many hybrids.  Our genetics have come so far since we finished the last drought in 2007 and were planting 18,000 seeds/acre in dryland.  We will just keep praying for rain and hope for the best next year!  Ultimately, test this and your other on-farm questions for yourself to know what will work for your farm!

If you’re interested in conducting some seeding rate trials, please let anyone on our UNL On-Farm Research Team know!  All our studies are posted on the CropWatch on-farm research page.

What planting rates are you considering for 2013?

 

Research Fertilizer Options for Your Farm

November 1 is just around the corner-the beginning of when fall fertilizing occurs in this area of the State.  Hopefully many of you have taken soil samples as excess nitrate is to be expected after this drought year.  This is an excellent time to consider evaluating your nitrogen program by starting an on-farm research trial!

On-farm research is using your own equipment, in your own fields, over single or multiple growing seasons allowing you to determine the most economical, efficient, and sustainable practice for the production of irrigated and/or dryland crops on your own farm.

What are the soil fertility questions you have for your farm?

Right now, with fertilizing on producers’ minds, we’re hoping you will consider a soil fertility study.  We have several example nutrient protocols including the UNL N fertility rate compared to +/- 30 lbs, and considerations for nitrogen timing studies such as pre-plant, sidedress, or fertigation.  You can view all these plot designs by clicking on 2012 protocols.  If you are planning on applying anhydrous this fall, be sure that the anhydrous strips are the correct width, as the corn must be harvested and weight determined in a correct manner next fall.

When designing a nitrogen comparison you need to remember nitrogen is a mobile nutrient and corn roots will spread laterally. Therefore, the width of the treatments must take this into account and compensate for it. If you have a 16 row nitrogen applicator and an 8 row corn head, you will need 32 rows of each nitrogen rate. Each 32 row strip must be repeated 4 times. At harvest, in each 32 row block, you must record and weigh the center 16 rows with two separate weights i.e. 8+8 . This is done for statistical analysis purposes. Without statistics, you cannot determine if differences between treatments is the result of the nitrogen rate or because of soil variability.

What’s in It for You?

On-farm research in your own fields allows you to find answers to the questions you may have.  We all read articles or hear presentations about various practices and products.  The question is “Will it work on my farm?“.  That’s what on-farm research allows you to find out!

UNL Extension Educators and Specialists are here to help you design your on-farm research trials, help you with data collection, and will statistically analyze the data for you at the end of the season.  Correct plot setup is critical to reduce any error in favoring one treatment over another (because we know fields are variable and some portions of the field will yield better than others).  The statistical analysis is another tool which helps us determine how much any yield differences between treatments are due to the treatments themselves or to chance.

So if you have an idea you’d like to try, please contact any of the UNL Extension Educators or Specialists working with on-farm research!  The Nebraska On-farm Research Effort is a partnership between the Nebraska Corn Board, Nebraska Corn Growers Association, and UNL Extension.

On-farm research may sound daunting, but today’s equipment makes it easier than ever.  It does take a little extra time, but our farmers conducting on-farm research feel the value of knowing the results of a study on their own piece of ground make the effort worthwhile.

What are some on-farm research studies you would like to conduct this year or that you would like our group to consider?

Harvest #Soybeans at 13%

In spite of green stems and even leaves on some plants, soybeans are surprisingly drier than what you may think.  I’ve been hearing reports of soybeans in the 7-10% moisture range already in spite of there also being some “lima beans” along with the low moisture beans at harvest.

Harvesting soybeans at 13% moisture is a combination of skill and maybe some luck.  Why is 13% so critical?  A standard bushel of soybeans weighs 60 lbs. and is 13% moisture.  Often beans are delivered to the buyer at lower moisture than 13%.  The difference between actual and desired moisture content will result in lost revenue to the grain producer.  Here’s how the loss works based on UNL Extension’s “10 Easy Ways to boost profits up to $20/acre”:

  • Since 13 percent of the weight is water, only 87 percent is dry matter. The dry matter in a standard bushel is 52.2 pounds and the remaining 7.8 pounds is water.
  • If this bushel of soybeans is kept in an open basket and some moisture is allowed to evaporate, the net weight of beans would decrease. If the dry matter weight remains unchanged at the standard 52.2 pounds, the wet basis weight for any moisture content can be calculated.
  • For example, a standard bushel at 13 percent moisture weighs 60 pounds. If the moisture content were reduced to 11 percent (89 percent dry matter), the wet basis weight per bushel of the soybeans would be 52.2 pounds of dry matter divided by .89=58.65 pounds. (1.35 pounds less than the standard 60 lb. weight of beans initially placed in the basket). For each 52.2 pounds of dry matter delivered at 11 percent moisture, you miss an opportunity to sell 1.35 pounds of water.
  • It is standard practice for buyers to assume 60 pounds of soybeans constitutes a bushel when soybeans are at or below 13 percent moisture. When the beans are below 13 percent, the difference in water content is made up for by an equal number of pounds (wet basis) of soybeans.
  • Assuming a 60 bushel per acre yield and selling price of $8.50 per bushel, the potential extra profit the producer could realize if the beans are harvested at 13 percent moisture instead of 11 percent is $11.48 per acre.

Rapid dry-down and difficulty harvesting green stems and pods are the most common reasons for harvesting at lower than standard moisture. The following practices can help producers maintain quality and expected moisture content.

  • Adjust harvest practices. When harvesting tough or green stems, make combine adjustments and operate at slower speeds.
  • Begin harvesting at 14 percent moisture. Try harvesting when some of the leaves are still dry on the plant; the beans may be drier than you think. Soybeans are fully mature and have stopped accumulating dry matter when 95 percent of the pods are at their mature tan color.
  • Plan planting dates and variety selection to spread out plant maturity and harvest.
  • Avoid harvest losses from shattering. Four to five beans on the ground per square foot can add up to one bushel per acre loss. Harvest at a slow pace and make adjustments to the combine to match conditions several times a day as conditions change.

Latest 2012 #Corn Yield Predictions

2012 Corn Yield Potential Forecast Based on Aug. 27 Hybrid-Maize Simulation:  Irrigated corn yield potential is predicted to be 2-8% below long-term average, while dryland yield potential in much of the Corn Belt will be moderately to severely reduced, falling 22-67% below normal. Predictions are assuming no stress during pollination and fully irrigated fields with no equipment, disease, or insect problems.
Map of sites used for yield forecasts

Figure 1. Locations used by the Hybrid-Maize model for in-season yield forecasting with actual weather and dominant management practices and soil series at each site (indicated by stars).  Green areas indicate where corn is planted.  Weather data used is from the High Plains Regional Climate Center and the Water and Atmospheric Resources Monitoring Program through the Illinois Climate Network (Illinois State Water Survey, Prairie Research Institute, and the University of Illinois at Urbana-Champaign). Link to a larger version of Figure 1. 

Simulations were run for dryland corn in Iowa, Illinois, and South Dakota, and for both irrigated and dryland corn in Nebraska. Simulations were based on the typical planting date, hybrid relative maturity, plant population, and soil properties at each location. Underpinning data used in these simulations are provided in Table 1. To evaluate the impact on potential production at 12 sites across the Corn Belt (Figure 1), we used the Hybrid-Maize model  to estimate end-of-season yield potential based on actual weather up to August 27, and historical long-term weather data to complete the season using data from each of the past 30 years. This approach gives a “real-time,” in-season estimate of expected yield potential (the median value shown in Table 1) depending on weather conditions from August 27 until the corn crop reaches maturity.

August 27 projections give a narrower range than our projections based on August 13 simulations, and, at some locations the crop reached blacklayer during the past week (Mead, Concord, O’Neill, and Nashua, Iowa). Projected yield potential since August 13 has not changed by more than 7% across all locations, except for the two locations in west central Illinois (Monmouth) and south central Illinois (Bondville) where predicted dryland yield has increased by 30% due to good rains and cooler weather. It should be noted, however, that if unusually hot, dry weather occurred during pollination at these Illinois locations, such a large yield improvement would not be expected due to reduced seed set. Still, projections of final yield potential are below the long-term average at all sites, under both irrigated and dryland conditions (Table 1).

The bottom line is that 2012 irrigated yields will be moderately lower than the long-term averages (2-8% below normal), while dryland corn yield potential in much of the Corn Belt will be moderately to severely reduced (22-67% below normal). It is important to keep in mind that yields can be even lower at places where both prolonged drought and high temperature stress at pollination have occurred. Also, greater field-scale variability is being observed this year in irrigated fields due to the inability of some irrigation systems to keep up with crop water use demand, problems with pivot irrigation nozzles and uneven watering, and additional stresses from insects and diseases. Such problems can contribute to reduced yields at irrigated sites of more than the 2-8% simulated by the model.There is a modest yield loss (5-8%) for locations in South Dakota (Brookings) and west central and north central Illinois (Monmouth and DeKalb) while a moderate yield loss of 22-28% is predicted for dryland corn in central and northeast Iowa (Gilbert and Nashua). Severe yield loss of 32-67% is projected for dryland corn in south central, eastern, and northeastern Nebraska (Clay Center, Mead, and Concord), northwest Iowa (Sutherland), and south central Illinois (Bondville) (Table 1). In contrast to large loss of yield potential in these dryland systems, the projected losses in yield potential at all irrigated sites are modest at about 2-3% in south central Nebraska (Clay Center, Holdrege), and 7-8% in east and northeast Nebraska (O’Neill, Concord, and Mead) (Table 1). Projected irrigated yield potential since August 13 has increased by about 3% due to cooler weather during the past two weeks.

Patricio Grassini, Research Associate Professor, Agronomy and Horticulture Department
Jenny Rees, UNL Extension Educator
Haishun Yang, Associate Professor, Agronomy and Horticulture Department
Kenneth G Cassman, Professor, Agronomy and Horticulture Department

Earlier Hybrid-Maize Predictions

Table 1.  2012 In-season yield potential forecasts as of August 17  using UNL Hybrid-Maize Model

Location, State Water Regime Soil Type&
Initial Water
Plant
Pop.
(ac-1)
Relative
Maturity
(days)
Planting Date Long-term
Yp
(bu/ac)
2012 Forecasted Yp (bu/ac)
 Median  

Holdrege, NE Irrigated Silt loam 32.4k 113  April 27  248
243  
Clay Center, NE Irrigated

Rainfed

Silt clay loam

100% ASW

32.4k

24.0k

113 April 23

April 23

 250
146
242
98
 
Mead, NE Irrigated

Rainfed

Silt clay loam

100% ASW

32.4k

28.0k

113  April 30  240
160
224
53
 
Concord, NE Irrigated

Rainfed

Silt loam

100% ASW

32.4k

29.0k

104 May 3 235
154
218
90
 
O’Neill, NE Irrigated Sandy loam

100% ASW

32.4k 106  May 3 225
207   

Brookings, SD Rainfed Silt clay loam

100% ASW

30.0k 98  May 4 120
110   

Sutherland, IA Rainfed Silt clay loam

100% ASW

31.4k 99  May 1 168
104    
Gilbert, IA Rainfed Loam

100% ASW

32.4k  110  April 26 200
145
 
Nashua, IA Rainfed Loam

100% ASW

32.4k 99  May 1 198
155  

Monmouth, IL Rainfed Silt loam

100% ASW

32.4k 112  April 27 212
189   
DeKalb, IL Rainfed Silt clay loam

100% ASW

32.4k 111  May 1 201
190
Bondville, IL Rainfed Silt clay loam

100% ASW

32.4k 114  April 20 197
134   

  Simulations based on dominant soil series, average planting date, and plant population (PP) & relative maturity (RM) of most widespread hybrid at each location (Grassini et al., 2009). 

 Average (20+ years) simulated yield potential (Yp). 

2012 Last Irrigation Scheduling

While farmers may be tired of irrigating right now, I think all who have irrigation are thankful for it in such a dry year.  Honestly, thankfully with our irrigation we have some of the best looking crops in the Corn Belt right now.  Even so, with corn that hasn’t been replanted nearing dent or stages of starch fill, you may be wondering how to schedule for your last irrigation.

For those of you in our Nebraska Ag Water Management Network using watermark sensors, the goal is to use them to determine when the soil profile reaches 60% depletion (for silty-clay soils in our area aim for an average of 160 kpa of all your sensors).  You may be thinking, “An average of 90kpa was hard enough!” but as Daryl Andersen from the Little Blue Natural Resources District points out, you’re only taking an additional 0.30 inches out of each foot.  So if you’re averaging 90kpa on your three sensors, you have depleted 2.34 inches in the top three feet so you still have 0.96 inches left (see the Soil Moisture Depletion Chart).  If you add the fourth foot (using a similar number from the third foot), it would bring the water available to the plant up to 1.28”. 

At beginning dent corn you need 24 days or 5 inches of water to finish the crop to maturity.  If you subtract 1.28 from 5 you will need 3.72” to finish out the crop.  Corn at ½ milk line needs 13 days or 2.25” to finish the crop to maturity-so subtracting it from 1.28 would be only 0.97”.  

Soybeans at the beginning of seed enlargement (R5) need 6.5”.  Soybeans in R6 or full seed which needs 3.5 inches yet for maturity.  Subtracting off the 1.28” in the four foot profile would lead to 2.22”.  The UNL NebGuide Predicting the Last Irrigation of the Season provides good information on how determine your last irrigation in addition to showing charts on how much water the crop still needs at various growth stages.  

Several people I’ve talked to who have been irrigating using watermark sensors aren’t replenishing the second foot, so you may have a few rounds yet to go  on corn and beans.  For a quick way to know where you’re at, think about irrigating this way as explained by Daryl Andersen at the Little Blue Natural Resources District:

One way to look at this is by the numbers of days left.  At 1/4 starch, there are about 19 days before maturity so you can let your sensors average 130kpa on the first week and 150kpa on the next week.  If these targets are met during the week, you would put on about 1 inch of water.  By going to these numbers, it might give you a higher probability for rain in the next couple of weeks.  I’m hoping for many answered prayers that we will see rain in August!

Southern vs. Common Rust in #Corn

In early July, southern rust caused by the fungal pathogen Puccinia polysora was discovered in Hall, Adams, Clay, Fillmore,  Thayer, and Burt counties in Nebraska.  Most farmers in south-central Nebraska remember the corn season in 2006 walking out of fields orange and the slow harvest due to downed stalks.  Since then, southern rust has been a disease of concern and fungicides are used to prevent and also treat it when it’s found in fields.  

I promised when we were first discovering southern rust this year that I’d post pics, so while delayed, here they are!  It is often confused with common rust which we see earlier every year.  Common rust typically has pustules (raised fungal spores) that are brick red in color, larger, and on the upper and lower leaf surfaces.  The pustules tend to be more spread out.  

Southern rust typically has very small pustules that are clustered on predominately the upper leaf surface and are tan to orange in color.  This year, southern rust pustules tend to be more tan in color than orange but are still distinctively different with their smaller and clustered appearance.  Both fungal rust pathogens arrive in Nebraska each year via wind from the south.  Southern rust prefers warm, moist conditions which, in spite of our dry spell, is typical within our pivot and gravity-irrigated fields in the area.  At this time we are recommending if you find southern rust in your field to consider treating with a fungicide.  Please be sure to read and follow all label directions including paying attention to pre-harvest intervals.  A list of corn fungicides and efficacy can be found here by scrolling down to the corn section.

Additional information and pictures of these diseases can be found here.

Crop Science Investigation Camp

This is the first year we are doing a Crop Science Investigation (CSI) Big Red Camp for youth! We’d encourage any youth who enjoy plants, science, and agriculture who are 15-18 years old and who are interested in having fun learning about these topics to check this out! Big Red Camps are open to youth in any State. Please help spread the word!

Views from VanDeWalle

Are you interested in science, agriculture, plants, crops, insects, or diseases? If so, join our team of detectives to solve crop-related problems in the Crop Science Investigation (CSI) Big Red Camp! Become a detective while participating in hands-on sessions to learn about and increase your knowledge of crops, science, and agricultural careers. Youth detectives will interact with agronomic professionals across Nebraska to solve experiments in: nutrient management; managing disease, insect and weed problems; water management; crop production, and much more! Do you have what it takes to become a CSI detective?

There are a variety of careers related to plant sciences such as: Agricultural Communicator; Agronomist; Crop Consultant; Crop Insurance Adjuster; Educator; Co-op Manager; Farmer or Rancher; Farm Credit Banker; Field or Lab Researcher; Plant Breeder; Soil or Water Conservationist; Seed, Fertilizer, or Chemical Sales; or Technical Representative.

Scholarships are available in the amount of $300 to participants…

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