Agronomic Report

Vol.1, No.10  10/3/17

All Corn Stalks Please Stand – and Why They May Not

Stalk lodging, by definition, is the breakage of the stalk below the ear. Severely lodged corn leads to increased harvest losses, increased harvest time, increased drying cost, and may result in volunteer corn the following year.  Annual yield losses due to stalk lodging in the U.S. range between 5 and 25%. In addition to outright yield losses, grain quality may also decline as a result of stalk lodging. 

As farmers start harvesting earlier planted corn fields they often encountered stalk lodging especially in fields that received little or no rain. For a corn plant to remain healthy and free of stalk rot, the plant must produce enough carbohydrates by photosynthesis to keep root cells and pith cells in the stalk alive and enough to meet demands for grain fill.

When corn is subjected to stress during grainfill, photosynthetic activity is reduced. As a result, the carbohydrate levels available for the developing ear are insufficient. The corn plant responds to this situation by removing carbohydrates from the leaves, stalk, and roots to the developing ear. While this "cannibalization" process ensures a supply of carbohydrates for the developing ear, the removal of carbohydrates results in premature death of pith cells in the stalk and root tissues, which predisposes plants to root and stalk infection by fungi. As plants near maturity, this removal of nutrients from the stalk to the developing grain results in a rapid deterioration of the lower portion of corn plants in drought stressed fields with lower leaves appearing to be nitrogen stressed, brown, and/or dead.

Other plant stresses which increase the likelihood of stalk rot problems include: foliar diseases, insects, or hail; limited root growth and development; improper nutrition – particularly late in the growing season; and high plant populations.

Most hybrids do not begin to show stalk rot symptoms until shortly before physiological maturity. It is difficult to distinguish between stalk rots caused by different fungi because two or more fungi may be involved. Similarly, certain insects such as European corn borer often act in concert with fungal pathogens to cause stalk rot.

The presence of stalk rots in corn may not always result in stalk lodging, especially if the affected crop is harvested promptly. It's not uncommon to walk corn fields where nearly every plant is upright yet nearly every plant is also showing stalk rot symptoms. Many hybrids have excellent rind strength, which contributes to plant standability even when the internal plant tissue has rotted or started to rot. However, strong rinds will not prevent lodging if harvest is delayed and the crop is subjected to strong winds and heavy rains.

A symptom common to all stalk rots is the deterioration of the inner stalk tissues can easily be compressed when squeezing the stalk between thumb and finger. It is possible by using this squeeze test to assess potential lodging if harvesting is not done promptly. The push test is another way to predict lodging. Push the stalks at the ear level, 6-8" from the vertical. If the stalk breaks between the ear and the lowest node, stalk rot is usually present.

To minimize losses for stalk lodging rot damage, avoid harvest delays. Identify fields that are at greatest risk and harvest these fields first. Fields which experienced late season drought stress or extensive disease pressure would be prime candidates for early harvest.

Vol.1, No.9  09/21/17

Harvest Loss, what is it and why is it important to manage it?

As harvest starts I thought I'd take a moment to discuss yield lost at harvest.

Harvest loss is exactly that; produced bushels left in the field harvested or not.  The impacts of harvest loss are both agronomic (volunteer crop competition the following year) and economic (reduced profits from the current and future years).  Volunteer corn can reduce soybean yields 1 - 20% or more and harbor insects through the "crop rotation" cycle potentially selecting for resistance to the traits in the volunteer crop.  Not mentioning the cost to control volunteer crop in the current growing crop or the potential for the price the grower receives at market being docked due to quality issues.

Some harvest lost can't be avoided, it happens before the combine ever got to the field via a lodged crop, dropped ears or the effects of weather stresses from earlier in the growing season.  While these losses can't be avoided they can be managed with a timely planned harvest.  Harvest losses of less than 1-2 bushels per acre can be achieved in reasonably well standing crops.  Timely harvesting of soybeans will typically start once the grain moisture reaches 15%.  In soybean, shatter losses have been shown to increase significantly when seed moisture falls below 11% and when mature beans undergo multiple wetting and drying cycles.  While grain corn harvest will start once typically once grain moisture drops below 23-25%.  Allowing corn to dry in the field to 16% moisture could lead to harvest losses as much as 2 - 8% greater than those from a timely harvest.  Harvesting grain in a timely manner with good grain moisture levels will help reduce the second form of harvest loss, mechanical loss.  

Most mechanical losses occur at the gathering head, about 66% of machine losses for corn and 90% of losses for soybeans, so particular attention should be paid there to avoid loss.  Additional harvest loss can happen within the combine itself through improper settings.  Watch this video on the Deere "GoHarvest" platform at https://youtu.be/Z5nt6a3-oek then check out the Deere "GoHarvest" app to better set your combine at https://itunes.apple.com/us/app/goharvest/id684295661?mt=8or https://play.google.com/store/apps/details?id=com.deere.goharvest The best guide for correct combine settings and adjustments is your operator’s manual

Measuring Soybean Harvest Loss

To determine soybean harvest losses, count the number of beans on the ground in a 10 square foot area.  Divide the number of beans in the 10 square foot area by 10 to determine the number of beans lost per square foot.  Four beans per square foot equals 1 bushel/acre loss.  Dividing the number of beans per square foot by 4 will give the loss in bushels per acre.  Make loss determinations at several locations and calculate an average.

Measuring Corn Harvest Loss

     Determine total ear loss by counting the number of full-size ears, or the equivalent, in a 1/100 acre area. Each full-size ear represents about 1 bushel/acre loss.  To measure kernel loss, count the loose kernels on the ground and those still attached to threshed cobs in a 10 square foot area for each row behind the combine.  The area should have width equal to the planted row width. Two kernels per square foot equals a 1 bushel/acre loss.  Make loss determinations at several locations and calculate an average.

Lastly, and most importantly, have a safe and bountiful harvest!

Vol.1, No.8  09/8/17

What's with some soybeans dying?

There could be many reasons outside the few following diseases - Sudden Death, Soybean Cyst Nematode, Brown Stem Rot or White Mold just to name a few.  

Let's take a little bit to discuss White Mold (also called Sclerotinia stem rot)

The disease, caused by the fungus Sclerotinia sclerotiorum, is not common every year, but farmers will want to assess the risk of white mold development as soybeans approach flowering growth stage R1 — (plants have at least one open flower at any node).  Yes, this infection took place in the days following the summer solstice as the soybean started flowering. 

White mold development is favored by cool, cloudy, wet, humid weather at flowering. The disease is more problematic in soybeans in high-yield environments where high plant populations, narrow row spacing, and an early-closing canopy are commonly used. No single management strategy is 100 percent effective at eliminating white mold, and in-season options for at-risk fields are limited.

If using fungicides for white mold management, keep in mind that efficacy may be based on the ability of the fungicide to penetrate into the canopy, and the timing of the fungicide application. Fungicides will be most effective at reducing the impact of white mold when applied at or close to growth stage R1.  Once symptoms of white mold are evident, fungicides will have no effect on reducing the disease. Fungicide applications for white mold management may be most useful on fields where varieties rated as susceptible to white mold are planted in a field with a history of the disease.  If a soybean field is diagnosed with high levels of white mold, this field should be harvested last. This will help reduce the movement of the survival structures of the white mold fungus by harvesting equipment, to fields that are not infested. Also, be sure to clean all harvesting and tillage equipment thoroughly at the end of the season to avoid inadvertent infestation of fields. Rotations of 2-3 years between soybean crops can help reduce the level of the fungus causing white mold in fields.

There is more to this conversation than what I've had room to discuss above, I welcome emails or calls to discuss this topic more.

Vol. 1, No. 7 May 31, 2017

Fungicide, Get a Head Start on Head Blight

The rainy wet weather of late is not only playing havoc on planting crops this year, the high moisture is fueling fungal spores that can damage existing crops. There are two main diseases that we need to make our clients aware of right now: Fusarium head blight or head scab and Anthracnose.

The wheat crop is looking good right now, but the yield has not been made yet.  Pollination is just starting across the GreenMark area and this is the prime time to spray a preventative fungicide treatment on the wheat crop.  Fusarium head blight or head scab can cause the head to produce no grain at the worst and at the least will produce mycotoxins in the head. If the mycotoxin level gets too high in the grain, the elevators will discount the grain our clients are trying to sell.  The use of either Prosaro by Bayer or Caramba by BASF will greatly reduce the risk of Fusarium head blight.  These fungicides have to be applied 2 to 7 day after flowering to have the maximum effectiveness against Fusarium head blight.  This application of fungicide will also help with leaf diseases that may be on the plant.              

This year’s corn crop has had a rough life so far, between the cold temperatures and the excessive moisture.   Anthracnose is a disease people associate with later in the year, but this disease can be devastating to a young corn plant.  Anthracnose leaf blight is characterized by oval- shaped spots with a dark brown or purplish border that are often surrounded by a yellowed zone.  The application of Headline AMP from BASF or Stratego YLD from Bayer will help wipe the disease off the plant.  These two fungicides can be applied with a planned herbicides pass, reducing the number of trips across the field.

In conclusion, make your clients aware the environment is right for these diseases.  They need to scout their fields and determine when and what type of fungicide to apply to help maximize their yield.  To prevent Fusarium head blight in wheat, the fungicide has to be applied while the flower is open and being pollinated.  Anthracnose can damage young corn plants and need to be treated as soon as the disease is detected.

Take away bullets:

  • Inform clients the environment is right for disease

  • Scout fields

  • Determine what disease is effecting the crop

  • Make a decision on what and when to spray

Vol. 1, No. 6 May 24, 2017

Don’t Compound Your Problems with Compaction

With the recent rains and soggy soils that we have been having this last week, compaction should be on everyone’s mind.  The ever increasing size of tractors and equipment, compaction can become a problem that will limit a client’s yield potential. How big of a problem will be determined by what kind of soil compaction is causing the problem.

There are two types of compaction farmers must be aware of, topsoil compaction and subsoil compaction.  Topsoil soil compaction is due to ground contact pressure only, whereas subsoil compaction is directly related to axle load.

Ground contact pressure is the pressure that is exerted by a tire or track on the soil surface, expressed in pounds per square inch (psi). Reducing contact pressures will cause less topsoil compaction. In completely flexible tires, surface contact pressure is similar to tire pressure. With most farm tires, surface contact pressure is about 1 to 2 psi higher than tire pressure due to stiffness in the tire. The best way to determine contact pressure is to calculate the load in pounds per wheel and divide it by the area of the tire that touches the soil (in square inches). This will give you the average contact pressure under that tire in psi.  Research shows yields can be reduced by as much as 10% due to soil compaction in the top soil. This compaction can be easily remedied with tillage and the natural freeze and thaw cycle.

Axle load is the total load supported by one axle, usually expressed in tons or pounds. Farm equipment with high axle loads will cause deep compaction.  Deep subsoil compaction can only partially be alleviated with subsoilers, and at considerable cost. Freezing/thawing and drying/wetting cycles have been shown not to improve soil compaction at this depth.  Research shows yields can be reduced by up to 15% with this type of compaction and will last up to 12 years.  This type of compaction should be avoided at all cost.

Soils that are near or at their water holding capacity will act like a hydraulic ram and will drastically increase the chances of both surface and subsoil compaction.

In conclusion, compaction no matter how slight can cause a yield reduction and should be avoided.  Keeping loads in the field as light as possible and driving on travel lanes will help in the majority of cases.  Driving on saturated soils can lead to long term damage and yield reduction.  Clients should be encouraged to stay off and not to “mud” in crops.  Once roots have been restricted, the client has restricted water and nutrient uptake into the plant.

Take Away Bullets:

  • Make sure clients have the proper tire pressure

  • Help clients calculate axle load

  • Try to encourage axle loads under 7 tons

  • Most important, stay off of saturated soils!

Vol. 1, No. 5 May 17, 2017

Is Corn Emergence Corkscrewed this Year?

The most important pass a farmer can make in his field is the planting pass.  With the ExactEmerge planters we can achieve 99% singulation, which also provides much-needed uniform spacing at emergence. 

Successful emergence only starts with the planting pass, there are many factors that have to occur.  Seedling emergence happens as a result of elongation of the mesocotyl that pushes the tip or spike toward the soil surface.  If everything goes correctly, the appearance of the spike at the surface of the soil will coincide with emergence of the first true leaf.  If the mesocotyl’s elongation gets stopped or impeded, it may start growing into a corkscrew configuration.  This could lead to a complete failure to emerge or the leaves could start emerging underground.

Cold soils or wide fluctuations in soil temperatures throughout the day during the emergence process can contribute in developing a corkscrewed mesocotyl.  In the last week we have had air temperatures moving as low as 30 degree Fahrenheit during the early morning and as high as 70 degrees Fahrenheit in the late afternoon.

A hard or crusted surface soil layer can restrict the mesocotyl from emerging properly.  This can be caused by several different factors.  An excessive amount of rain can cause soil crusting at the surface.  Wet soil conditions at planting can cause severe sidewall compaction plus press wheel compaction over the furrow.

Herbicides, acetochlor especially, can affect the mesocotyl root development if the seedling’s growth conditions are slowed due to weather or soil conditions.  However when herbicide injury is suspected to be the culprit, cool soils and dense soil crusting are often also contributing factors, so is difficult to pin the blame completely on the herbicide injury.

In conclusion, the planter pass is the most important field pass the farmer can make.  It can also be blamed for a few seedling issues that are out of the planter’s control.  If you are questioned about a “crappy” corn stand, it’s not always an equipment issue.  There can be other factors at play and maybe digging a few seedlings up will uncover the real problem.

Take Away Bullets:

  • Planters are not always to blame for poor emergence

  • Check air temperature 2 weeks after planting

  • Look for hard or crusted surface soil

  • Ask if and what herbicides have been applied

  • Most important, dig up the seed!

Vol. 1, No. 4 May 10, 2017

To Replant, or Not to Replant: That is the Question

Should I replant my soybean crop and risk a late planting date or live with my emerged soybean population and risk a reduced yield?  This question is brought to my attention every spring.  Reduction in emerged soybean population can be a result of inaccurate planter adjustment, planting too fast, soil crusting, soil moisture extremes, pesticide drift, insects, or disease pathogens.

The first and most important step is to accurately determine the emerged soybean population.  The person scouting the field should wait several days after emergence to make sure all the viable soybean seeds have emerged.  Pick multiple sample areas at random across the entire field. There should be enough sample areas to give a good representation of the whole field.  There are two common methods for estimating plant populations: counting plants in a row and using the hula hoop method. No matter which method you use, be sure to count only live plants.  If specific field locations are a concern, separately determine the stand in those areas.

Once you know the living soybean population, you can make an educated decision to replant.  Most tables show less than a 10% reduction in yield down to a population of 60,000 plants/ac.  University data indicates that there is no yield advantage to filling in a stand of 66,000 or greater plants per acre. That’s because the second planting yield potential is lower due to the later planting date and competition from the original planting.  The second planting can further damage the original thin stand by up taking nutrients and water.  A soybean plant that will not yield grain becomes a weed that the farmer can’t kill. 

If a client decides to keep the lower population, there are a few more management options that needs to be considered.  Weeds, the client needs to be aware of the chance of higher weed pressure due to a greater percentage of the ground not being covered by soybeans.  An additional spray pass of herbicide will be needed, since the soybean canopy will take longer to close.  Foliar fertilizer, adding a foliar fertilizer to the additional herbicide pass will help jump start the vegetative growth of the soybeans and decrease the time to canopy.

In conclusion, when faced with a less-than-desirable soybean stand farmers have a very big decision to make.  We can reduce the stress our clients feel by providing reliable information so the client can make an educated decision in a timely manner.

Take Away Bullets:

  • Accurately determine the emerged population.

  • Decide if the field needs to be replanted.

  • Make the proper management decisions to insure maximum yield.

  • AgDNA can be a very good source to make an educated decision.

Vol. 1, No. 3 May 03, 2017

Nitrogen, It’s What’s for Dinner

There has been a long debate on timing of nitrogen application.  Purdue has shared a 3 year study from the Penny Purdue Farm around Wanatah, IN.  The results are surprising to some not familiar with preplant nitrogen application. Dr. James Camberato applied the corn crops total nitrogen needs before planting and compared the yield to a split application of 40 units preplant and the remainder at side dress (V4).  The results were statistically no different to a slight advantage for the total preplant application.  Dr. Camberato suggest two reasons for his results.  First, nitrogen is taken up into the plant thru mass flow and usually in the spring there is plenty of soil water to bring the nitrogen into the plant, whereas, late side dress can coincide with dry weather.   Secondly, when nitrogen is applied during preplant the crop will have nitrogen available as soon as the seed hits the ground.

John Deere and Greenmark will always recommend to comply with the 4R principles of right fertilizer source, right rate, right time, and right place.  Dr. Camberato’s study is just one of many that is worth looking into and replicating.

How many units of nitrogen should I apply?  This question is asked every season.  The answer is not as straight forward as it sounds.  As an agronomist, I look at a soil test to see what kind of soil or more specifically how much cation exchange capacity (CEC) and organic matter does the soil have on that particular farm ground. In general, the higher the CEC the more potential for higher yields.  Likewise, a high organic matter soil such as muck or black sand, will not need as much commercial nitrogen added to the soil as a low organic matter soil.

In conclusion, while split applying nitrogen will have the least amount of loss, there seems to be no yield difference between preplant nitrogen application and sidedress application in recent studies.  Late nitrogen application with the use of Y-drops have shown some promise of yield increase, especially in years of heavy rain pressure due to the movement of nitrate (NO31-) out of the root zone. The use of a nitrate inhibitor in any nitrogen application will greatly decrease the chances of nitrogen loss due to leaching or denitrification.  The lower the organic matter that a soil has, the more commercial nitrogen will need to be added to achieve your full potential yield.

Vol. 1, No. 2 April 26, 2017

Micronutrients Not Fancy but Essential
 

As the title suggests micronutrient applications are not the most widely talked about in the agriculture industry.  They are not applied or sold by the ton, you may not even know your crop is deficient.  The term we in the industry like to bat around is “Hidden Hunger”.  Which means you may be raising a 190bu/ac corn crop, but if you position certain micronutrients in the root zone you may increase your yield to 210bu/ac.  The two micronutrients that have the greatest effect on corn production are zinc and sulfur.

Sulfur deficiency is becoming more prevalent.  We have been seeing a documented reduction in sulfur dioxide in the atmosphere for the last 30 years.  This is mainly due to power plants and automobiles removing sulfur from their exhaust. Corn grains contain .5 pounds of sulfur for every 10bu of grains. With the trend line corn yield ever increasing, we are taking more sulfur out of the root zone than what is being replaced naturally. Your corn crop will pick up sulfur as Sulfate which has a double negative charge (SO42−) making sulfate very mobile in the soil, a kin to nitrate (NO31-).  Since sulfate can be leached out of the root zone very quickly, the application must be timely and be correctly placed.  This is why putting sulfur in with your 2x2 or popup starter can not only help with sulfur deficiency, it will also reduce the pH in the root zone allowing more micronutrient to become more available.

Zinc, the granddaddy of all micronutrients, is deficient in a corn cropping system more than any other micronutrient.  Zinc is an important component in the production of multiple enzymes that are responsible for metabolic reactions in the corn plant, such as photosynthesis and DNA transcription.  Most zinc in the soil is unavailable to the corn crop.  Plants can only take zinc up that is dissolved in the soil solution, absorbed to the surface clay particles, or absorbed by and chelated with organic molecules in the soil organic matter.  Cool wet conditions may result in less zinc in an available form.  More and more farmers are planting into cool wet soils, placing a concentrated band of high quality zinc in with your starter will solve early zinc deficiency in your corn crop.      

John Deere can provide a very efficient way of delivering these nutrients through our planters.  Most studies show placing P, K, and micros in the seed furrow and nitrogen in a 2x2 application will be the biggest return on the investment.

Vol.1, No.1 April 19, 2017
 

As winter losses its icy grip, spring is fast approaching and the burndown season will be here if not already started on some of our sandier fields.  The warm wet weather earlier in the spring have the winter annual weeds such as chick weed and purple dead nettle, taking over fields in a glorious fashion this year.  This season of burndown will be the first time dicamba will be available to be sprayed late in the spring season in front of dicamba-resistant soybeans.  As everyone has probably heard by now, there are federal labels for the use of 3 dicamba products, on dicamba-resistant (Xtend) soybeans. These products are Xtendimax (Monsanto), FeXapan (DuPont), and Engenia (BASF).  These products are not a magic wand but a tool that have a whole list of regulations tied to its on-farm application.  The main issue with a dicamba application is off target spray.  This can derive from drift, volatilization, and tank contamination.  Many clients still operate older sprayers.  These sprayer may not contain an efficient process to apply the mandated 110ft buffer strips around the field or they may contain “blind spots” that can harbor dicamba and contaminate spray solutions.  We should look at these inefficiencies as opportunities that can showcase the newest technology in sprayers.  As the old saying goes, “Take your lemons and make lemonade”.