C.O.R.N. Newsletter 2006-13

Dates Covered: 
May 15, 2006 - May 23, 2006
Editor: 
Tammy Dobbels

Flea Beetles on Corn

Authors: Ron Hammond, Pierce Paul, Bruce Eisley

As our predictions early in March had suggested, we are seeing higher populations of corn flea beetle in parts of Ohio. One report we received was from a field that was conventional tilled that had 100% of the plants showing flea beetle damage and over 5 beetles per plant. Growers are advised to scout their fields to make sure flea beetles are not causing injury to their corn. Check 20 plants in 5 places for flea beetle on newly emerging corn plants. Treatment is warranted if 3% of more of the plants are wilting/dying or show signs of severe feeding. If treatment is required, labeled insecticides can be found at http://entomology.osu.edu/ag/545/cifb.pdf . Additional information on the flea beetle can be obtained from OSU Extension Fact Sheet CV-1000-94.

Also of concern is the beetle’s ability to transmit Stewart’s bacterial blight. The bacterium causing this disease is carried and spread by the adult beetle. In the spring, as corn emerges from the ground, flea beetles feed on the young plants and spread the bacterium which in turn causes seedling wilt and leaf blight. If growing hybrids susceptible to this disease, growers should check their corn for the beetle’s presence. There is a direction relationship between beetle population and the level of disease; however, high beetle population does not always mean high levels of Stewart’s wilt. The easiest way to determine if the beetles are actually carrying the bacterium and transmitting the disease is to look for wilted plants. At the current crop growth stage (early vegetative stages), diseased plants wilt rapidly and show symptoms that closely resemble plants with drought and nutritional deficiency. Early symptoms are best seen during the warmer hours of the day. You can see pictures of flea beetle injury (feeding scars) and Stewart’s bacterial leaf blight (most common after tasseling), and get additional information on Stewart's disease of corn, on the Ohio Field Crop Disease web site at http://www.oardc.ohio-state.edu/ohiofieldcropdisease/corn/stewarts.htm

Cutworm Feeding Observed

Authors: Ron Hammond, Bruce Eisley

We observed slight cutting by cutworm in 1-2 leaf stage corn last week in central Ohio. We did not find any worms at this time so do not know which species might be causing the damage. The cutting we observed was slightly at and slightly ground level. This was before the rainfall and so with wet soils we might see cutting higher on the plants this week. The cutting was only slight and not near treatment threshold at this time. However, it does indicate that it is time to begin checking for cutworm in any corn that has emerged.

We mentioned these web sites last week but will list them again. Insecticides labeled for cutworm rescue treatment can be found at: http://entomology.osu.edu/ag/545/cicw.pdf. For additional information about BCW and other early season pests of corn, see OSU FactSheet FC-ENT-12 at http://ohioline.osu.edu/ent-fact/0012.html

Ponding Effects on Corn

Authors: Peter Thomison

The recent rains have been beneficial for many corn fields across Ohio. Dry soil conditions were raising concerns about the efficacy of preemergence herbicide applications, and delayed emergence and uneven stands. However, in some areas, heavy rains resulted in localized ponding. If this ponding is limited, the injury resulting from the saturated soil conditions should be minimal given the relatively cool conditions we are currently experiencing. The following are some tips to consider when evaluating possible damage from water saturated soil conditions.

The extent to which ponding injures corn is determined by several factors including: (1) plant stage of development when ponding occurs, (2) duration of ponding and (3) air/soil temperatures. Prior to the 6-leaf collar stage (as measured by visible leaf collars) or when the growing point is at or below the soil surface, corn can usually survive only 2 to 4 days of flooded conditions. The oxygen supply in the soil is depleted after about 48 hours in a flooded soil. Without oxygen, the plant cannot perform critical life sustaining functions; e.g. nutrient and water uptake is impaired, root growth is inhibited, etc. If temperatures are warm during ponding (greater than 77 degrees F) plants may not survive 24-hours. Cooler temperatures prolong survival. Once the growing point is above the water level the likelihood for survival improves greatly.

Even if ponding doesn't kill plants outright, it may have a long term negative impact on crop performance. Excess moisture during the early vegetative stages retards corn root development. As a result, plants may be subject to greater injury during a dry summer because root systems are not sufficiently developed to access available subsoil water. Ponding can also result in losses of nitrogen through denitrification and leaching.

If ponding in corn lasts less than 48 hours, crop injury should be limited. To confirm plant survival, check the color of the growing point. It should be white to cream colored, while a darkening and/or softening usually precedes plant death. Also look for new leaf growth 3 to 5 days after water drains from the field. Sometimes the growing point is killed by bacterial infections during and after ponding, but plant growth continues in the form of non-productive tillers (suckers).

Disease problems that become greater risks due to ponding and cool temperatures include pythium, corn smut, and crazy top. Fungicide seed treatments will help reduce stand loss, but the duration of protection is limited to about 10-14 days. The fungus that causes crazy top depends on saturated soil conditions to infect corn seedlings. There is limited hybrid resistance to these diseases and predicting damage from corn smut and crazy top is difficult until later in the growing season.

Postemergence Application Timing in Corn

Authors: Mark Loux

The current spell of rainy weather should provide growers and agronomists with a good opportunity to scout corn fields for developing weed problems. As we discussed in last week’s C.O.R.N., preemergence (PRE) herbicides were not completely effective in many field where rain was scarce within 10 days or so after herbicide application, and it is important to determine where this occurred. Fields not treated with PRE herbicides should also be scouted so that postemergence (POST) herbicides are applied in a timely manner. Some important guidelines for POST control of weeds in corn:

- In the absence of PRE herbicides (i.e in total POST herbicide programs), POST herbicides should be applied before summer annual weeds exceed about 3 to 4 inches in height. This corresponds to approximately 20 to 25 days after crop planting. Allowing weeds to become larger than this size results in the risk of crop yield loss due to early-season weed interference. Applying POST herbicides to 6-inch weeds results in an average yield loss of 6%, compared to earlier applications, and the loss increases with weed size.
- Where an effective rate of a broad-spectrum PRE herbicide program was used, and it was initially active due to timely rain, POST application timing is less critical than in total POST programs. This is because the PRE herbicides reduce the weed population and slow the growth of emerging weeds. The end result – POST herbicides can often be applied a little later in the season, which works well for control of late-emerging weeds.
- Where PRE herbicides have not been completely effective due to an initial scarcity of rain, it may be more difficult to determine the timing of POST applications. Where the PRE has largely failed and there is a fairly dense weed population, it is essential to apply before weeds exceed 3 to 4 inches in height to avoid yield loss. Where the PRE herbicides have been somewhat active, it may be a possible to apply POST herbicides later and still not suffer crop yield loss.
- The above guidelines all pertain to management of weeds to avoid yield loss, but timing should also be based on the limitations of the herbicides with regard to weed size. The size of annual grasses is often a determining factor for POST application timing, because large grasses are more difficult to control than large broadleaf weeds with conventional POST corn herbicides. Labels for most POST grass herbicides (Option, Steadfast, etc) specify application when grass weeds are 4 inches tall or less (see accompanying article). For these herbicides, the previous discussion about POST application timing, based on the competitive nature of weeds, becomes unnecessary because they have to be applied when grasses are small to obtain adequate control. So, for those growers evaluating options where PRE herbicides have not been completely effective, the real question may be whether to apply when grasses are less than 2 inches tall in order to reduce costs, or apply when grasses are about 4 inches tall to try to improve control of late-emerging weeds.
- Making the choice to plant Liberty Link or Roundup Ready corn can pay off in a year when PRE herbicide activity is so-so. Liberty and glyphosate both have broad-spectrum activity, although there is less flexibility in timing of Liberty application with regard to weed size. Liberty controls giant foxtail up to 6 inches tall, while glyphosate can control grasses well over 6 inches tall. Keep in mind, however, that in total POST programs or where a lack of rain has resulted in a complete failure of PRE herbicides to reduce early-season weed populations, Liberty and glyphosate should be applied when weeds are less than about 4 inches tall to avoid corn yield loss.
- University research has shown that the critical period of weed control in corn occurs between approximately 20 and 45 days after planting. Controlling weeds during this period is essential to avoid crop yield loss. So, total POST herbicide programs applied at about 20 to 25 days after planting will minimize competition from weeds that emerge with the corn, but these programs should also contain a residual herbicide component to control weeds for another several weeks. Weeds that emerge later than about 45 days after planting should not reduce corn yield due to the ability of a well-developed corn canopy to suppress late-emerging weeds.

Postemergence Grass Herbicides in Corn

Authors: Mark Loux

Some guidelines on postemergence grass herbicides for field corn follow. Grass sizes listed are either the range in size or maximum size at the time of application of labeled rates, and pertain primarily to foxtails, panicum, and barnyardgrass. See herbicide labels and the current Weed Control Guide for Ohio and Indiana for additional information.

Accent: apply when annual grasses are 2 to 4 inches tall; apply broadcast or as directed spray up to 20-inch or 6-collar corn (whichever occurs first); directed spray up to 36-inch or 10-collar corn.
Celebrity Plus: apply when annual grasses are 2 to 4 inches tall; apply broadcast or as directed spray up to 24-inch or 6-collar corn (whichever occurs first).
Equip: foxtails, fall panicum – up to 3 inches tall; barnyardgrass – up to 4 inches tall; apply broadcast to corn in the V1 to V4 stage; directed spray up to 36-inch or V8-stage corn.
Glyphosate (Roundup Ready Corn 2): Labels generally recommend applying before weeds become competitive, so application when weeds are less than 4 inches tall is preferable (see accompanying article on POST principles in corn). Glyphosate can control grasses larger than 4 inches tall – see labels for rate and size information. Apply broadcast up to 8-collar stage or 30-inch corn (whichever occurs first); directed spray up to 48-inch corn.
Liberty (Liberty Link corn): yellow foxtail, fall panicum, barnyardgrass, crabgrass – up to 3 inches tall; giant, green, and robust foxtails – up to 6 inches tall; apply broadcast to corn up to 24 inches tall or the V7 stage (whichever occurs first); directed spray from 24 to 36-inch corn.
Lightning (Clearfield corn): annual grasses up to 3 inches tall; apply broadcast to corn up to 20 inches tall or the V6 stage (whichever occurs first); directed spray until 45 days before harvest.
Option: foxtails, fall panicum – up to 3 inches tall; barnyardgrass – up to 4 inches tall; apply broadcast to corn in the V1 to V6 stage; directed spray when corn is 16 to 36-inches tall.
Resolve: apply when annual grasses are 1 to 2 inches tall; apply broadcast up to 12-inch or 6-collar corn (whichever occurs first).
Steadfast: annual grasses up to 4 inches tall; apply broadcast or as directed spray up to 20-inch or 6-collar corn (whichever occurs first).
Steadfast ATZ: most annual grasses up to 4 inches tall; apply broadcast up to 12-inch or 6-collar corn (whichever occurs first).

Should I Apply Fungicide as a Preventative Against Wheat Diseases?

Authors: Pierce Paul, Dennis Mills

CONCERN: Now, growers are asking whether they should fly on fungicide on their wheat as a preventative against diseases. They are concerned that the cool, wet weather will cause disease to show up in about 10 days or so.

RECOMMENDATION: Remember, rainfall (the weather) is only one of three basic conditions that have to be satisfied for plant diseases to develop. The other two are the presence of the disease-causing fungi and the susceptibility of the variety. I agree that the recent rainfall may be a cause for concern; however, the decision to apply fungicide should still be based on disease threshold levels and variety susceptibility. Fields should be scouted to determine which disease is present and at what level. Rainfall will only spread the disease-causing fungi and cause the disease to spread to the upper leaves if it is already present in the field. In addition, for most of the major disease for which fungicides are recommended, warmer conditions are required for disease development. Powdery mildew develops best at temperatures between 60 and 75oF, whereas Stagonospora leaf blotch develops well under conditions of frequent rainfall and temperatures between 68 and 80o. Flag leaves are already out and if lesions are not found on the leaves below the flag leaf at this time, the chances of disease spreading to the flag leaf are greatly reduced. Remember, the goal of fungicide application is to protect the flag leaf and the head. With the current rainfall pattern, if it warms up, fields would need to be scouted more frequently to determine which disease is present and whether the threshold level for that disease is reached. More information on scouting and disease thresholds can be found in a recent C.O.R.N Newsletter (2006-11; Scouting & Managing Leaf Diseases of Wheat With Fungicides by Pierce Paul, Dennis Mills, Jim Beuerlein) at
http://corn.osu.edu/story.php?setissueID=132&storyID=767

Wheat Scab Update

Authors: Pierce Paul, Dennis Mills

The recent rainfall means that conditions are becoming more favorable for the wheat scab fungus to produce spores in wheat fields. Once moisture is available, spores may be produced under a very wide range of temperature conditions (between 55 and 78 F). However, infection of the wheat heads by the fungus requires warmer temperatures and occurs during flowering. So, at the current time, the risk of scab is still very low, mainly because the wheat is not yet flowering and temperatures have been low. Most of our wheat is currently between boot and early head emergence. If the rains persist and the wheat begins to flower within the next week or so, the risk of scab will increase. Now is the time to start keeping your eyes on the scab prediction center at http://wheatscab.psu.edufor frequent updates. As the weather changes and the wheat crop begins flowering, the scab prediction center will be updated regularly with comments specific for Ohio.

We do not recommend Fungicide application for wheat scab control. Fungicides have just not been effective enough against this disease and the toxin (vomitoxin or DON) produced by the fungus.

Wheat, Virus Infection, or Nutrient Deficiency, What is Affecting the Wheat Crop?

Authors: Pierce Paul, Jim Beuerlein, Dennis Mills

Yellowish wheat in patches or strips in fields alongside nice green (normal-looking) wheat; stunted plants with poorly developed root systems; burnt leaf tips; dark, discolored nodes and internodes; and dead flag leaves and growing points on some tillers. These are the symptoms seen in wheat samples and pictures or described from affected fields in northern and northwestern Ohio over the past two weeks. The extent of the symptoms varies from field to field, mainly restricted to small patches in some fields and more widespread in others. In some cases, the affected plants were restricted to sand ridges.

WHAT IS THE PROBLEM?: Samples submitted to the laboratory had clean roots without signs of any damage caused by root pathogens. Although Fusarium species were recovered from some samples, we do not believe that root pathogens are the main cause of these problems. There are likely other predisposing soil and weather factors. Some of symptoms described above may be caused by virus diseases, nutrient deficiency, or extreme temperature or moisture conditions. For instance, yellowish strips of wheat fields interspaced with normal-looking wheat are likely the result of uneven nitrogen application or poor nitrogen up-take in some sections of the field. The lack of rainfall during the spring likely affected nitrogen up-take. Stunted wheat with poorly developed root systems may also be the result of nitrogen deficiency. However, some viruses are known to cause similar type of symptoms, and samples collected from some fields suggest that virus infections may have occurred in some locations. In particular, some of the symptoms resemble those caused by barley yellow dwarf virus (stunted plants, yellow or purple discoloration of leaf tips), and wheat yellow mosaic virus (yellowish-green mottling and streaks and discolored leaf tips). For both viruses, fall infection is more damaging than spring infection and symptoms are usually seen in patches rather that across entire fields. Since it is very difficult to separate virus infection from nutrient deficiency and frost damage, definitive diagnosis requires laboratory tests.

FROSTED WHEAT: On April 26, 2006 the air temperature dropped to 24 degrees for several hours in some northern Ohio counties damaging wheat that was between growth stage six and eight. The damage consists of killed leaf tissue and primary tillers. The fields most affected were those at the most advanced stage of growth. In many cases the primary tiller will not produce a head, however the secondary tillers appear unaffected in some fields and should develop normally and produce grain. The percent of primary tillers damaged in a particular field or part of a field is very difficult to estimate at this time but should become more discernable around May 20-25 depending on the weather and amount of growth in the meantime.

MAKING A DECISION: Decision making considerations should include the price of wheat at harvest time, bushels already contracted, amount of nitrogen applied, potential alternative crops, and the extent of damage to the crop. Supporting information includes the following: 1) If all the primary tillers are lost, the yield potential is between 70 and 85 percent of normal depending on the stage of growth and the condition of the crop. 2) Most of the nitrogen applied to the wheat can be recovered by a corn crop although the planting date of a corn crop will be rather late except for silage corn. 3) The nitrogen applied to the wheat can be used by soybeans and may increase their yield a small amount. 4) By the end of May, the dry matter yield on the wheat taken as hay, silage, or greenchop should be about two tons per acre. 5) Once headed, wheat is very difficult to kill.

I Terminated My Wheat Stand (After Topdressing), How Much Nitrogen can I Count on for My New Corn Crop?

Authors: Edwin Lentz, Robert Mullen

Perhaps a few producers have to face this situation this year. You planted wheat in the fall and at first green-up this spring you applied some topdress nitrogen. The wheat crop was proceeding along nicely, and the late frost/freeze we experienced in late April may have done in your crop (this was primarily isolated to the North Central and Northeastern parts of our great state). If you are planning on going to corn this year, you may be wondering how much of the nitrogen I supplied for wheat will be available to my corn?

The answer is we do not know exactly, but we can get a somewhat reasonable estimate. The amount available depends upon a few key factors – 1) form of nitrogen applied, 2) depending upon form – time difference between nitrogen application and rainfall, 3) rainfall patterns since application, and 4) application rate.

Form of Nitrogen Applied
Different forms of nitrogen applied to the soil surface have different levels of risk for nitrogen loss, so we have to make some assessment of the risk of your specific operation. Dry urea is a popular form of nitrogen that can be applied to the surface of the soil, but under the right conditions we can lose a substantial amount of nitrogen through volatilization (the amount that can be lost is dependent upon how long the material sat on the soil surface and on rainfall patterns – next section). Liquid urea-ammonium nitrate (UAN) can be subject to volatilization as well, but at least half of the total amount of nitrogen applied is in an ammonium or nitrate form which is not subject to volatilization. Ammonium sulfate (solid or liquid) is not very susceptible to volatilization losses, so application of this material represents little risk of nitrogen by volatilization even if we do not receive a quick rain. One saving grace of surface applied urea-based fertilizers early in the spring is that they do not break down as quickly as an application made in late spring (due to soil temperature and microbial activity). So they can rest comfortably on the soil surface longer without running the risk of volatilization losses of nitrogen.

Nitrogen Application and Rainfall
The length of time between surface application of a urea-based fertilizer and a substantial rainfall event is important when attempting to estimate the amount of nitrogen lost. Early-spring applied urea fertilizers can remain on the soil surface for a longer period without experiencing nitrogen loss, but surface incorporation of urea by a little rainfall reduce the risk of nitrogen loss to nil. If you did apply urea (or UAN) and at least 0.25 – 0.30 inches of rain fell a few days after application, you should have lost very little nitrogen and you can count on more being available for your corn crop. We still have to consider rainfall patterns between the time of application and the time your corn will need nitrogen. If conditions were moist but not enough to reach the 0.25 inch mark, you could have lost some nitrogen, and you may need to supply a bit more to ensure your corn crop performs adequately.

Rainfall between Timing of Nitrogen Application and Corn Demand
Rainfall patterns and soil temperatures following the application of topdress nitrogen for wheat will influence how much nitrogen could be potentially lost as nitrate leachate or nitrous oxide gas. Early spring weather was not conducive to nitrate leaching or denitrification, but the last week has been extremely wet. Fortunately, soil temperatures have not gotten that high, so microbial activity has been somewhat limited and denitrification losses should have been minimal. If your conditions have been relatively wet you may consider applying a little more nitrogen to ensure an adequate amount will be available.

Nitrogen Rate for Topdress
This is an important consideration especially when making your decision on the newly planned corn crop. If you followed Ohio State University nitrogen recommendations and applied between 70 and 90 pounds of nitrogen per acre this spring that will be our starting point to estimate how much nitrogen will still be available (fall applied nitrogen will not be considered). The final thing to consider is how much of the nitrogen applied to the wheat was taken up and how much remains in the soil system? This really depends upon the growth stage of the wheat when it was killed and the amount of biomass accumulated at that point. Since we do not have a really good measurement, we will base our estimate on common nitrogen accumulation for a specific growth stage. Assuming the crop was terminated near Feekes growth stage 8-9, the wheat crop had accumulated about 50% of its total nitrogen demand (assuming a 70 bushel yield potential wheat crop that would equate to 75 pounds of nitrogen per acre). Thus if you had applied 90 pounds of nitrogen per acre (assuming an unfertilized wheat crop would accumulate approximately 50% of the well-fertilized) the crop would have taken up approximately 40% of the nitrogen applied. Theoretically, you should have about 60 pounds of nitrogen still available in the soil.

Nitrogen Recommendation for Corn
If you applied 100 pounds of nitrogen per acre and you received rain shortly after the topdress application and you were not excessively wet between the time of the application and now (which thanks to the last week may have occurred if all ammonium-nitrogen was converted to nitrate-nitrogen), you should credit about 50 pounds per acre of available nitrogen. We would recommend at least 80 and 100 pounds of nitrogen per acre. You can also use the online nitrogen rate calculator (https://agcrops.osu.edu/fertility/), enter your economic parameters, and subtract 50 pounds from the recommendation. If your application rate was lighter than 100 pounds and you had relatively wet conditions you may want to supply a little more nitrogen. This is not perfect, but if you follow logically through the topics here you should get a pretty good idea of your nitrogen rates you need for your corn. You can also utilize the pre-sidedress soil nitrate test (PSNT) to determine if additional nitrogen application is necessary. PSNT values greater than 25 ppm are unlikely to benefit from additional fertilizer nitrogen. If the PSNT value is less than 25 ppm supply follow the recommendation above.

Broadcast versus Banded Applications of Fertilizer – Which is the Best?

Authors: Robert Mullen, Peter Thomison, Edwin Lentz

This question often arises – am I better off to band all my nutrients or should I make a broadcast application? Like most extension questions, the answer is ‘it depends’. The factors to consider when deciding how to supply crop nutrients are: 1) what nutrients am I considering, 2) what is my current soil test level, and 3) am I planning on growing row crops or solid seeded crops. Band or broadcast applications of fertilizer have their place; you just need to know when to use which methodology.

Consider the Nutrient
Immobile nutrients and mobile nutrients behave differently in soils (obviously) and this impacts application methodology. Immobile nutrients to do not move across great distances within a soil system, so banding immobile nutrients can improve positional availability. Banding supplies a nutrient in a high concentration zone and decreases soil-nutrient interaction. For nutrients that are subject to fixation (phosphorus being our best example), banding can improve efficiency and result in increased yield. For other soils banding immobile nutrients may not result in higher yields when compared to broadcast applications. Mobile nutrients move with soil water, so application in a band is only short term, eventually the nutrient will diffuse away from the concentration zone. Is there sound agronomic evidence showing that banding is better, more efficient than broadcast? Yes and no, it depends upon the situation and the nutrient.

Nitrogen
Tillage system and the form of nitrogen used influences whether or not nitrogen should be band applied or broadcast. Minimum tillage systems that maintain a large amount of surface residue should not receive broadcast applications of dry or liquid urea-based products due to the risk of volatilization. Clean-till corn production systems are less susceptible to volatilization losses of nitrogen but they can and have been documented to occur. For liquid urea fertilizers, band injection and surface banding are more efficient than surface broadcast applications. Non-urea nitrogen fertilizers can be applied by either method with similar results.

Phosphorus
As mentioned above, band injection of fertilizer phosphorus can decrease fixation improving availability. Improved efficiency and yields have been documented with banded applications of phosphorus especially in soils that have high fixation capacities. Soils that have high fixation capacities are highly weathered soils that have a large amount of free aluminum, iron, or calcium (soils with low or high pHs). Yield benefits from banded phosphorus are also more common in soils with low soil test levels and soils that are cool and wet. Warm soils that receive adequate moisture are less likely to benefit from band fertilizer applications.

Potassium
Like phosphorus, potassium is an immobile nutrient and band applications can benefit nutrient use efficiency and yield. The benefit is most noticeable for cool, wet soil conditions. There is also some research that shows that sub-surface band injection can be beneficial to production under minimum tillage production systems, but not with chisel plow tillage (http://www.ent.iastate.edu/Ipm/Icm/2000/9-18-2000/deepband.html).

Current Soil Test Levels
This is a major consideration when determining which application method will provide the greatest benefit. Soils rich in plant available nutrients are productive with either methodology, but broadcast applications of nutrients can help maintain adequate soil test levels. Crop production on deficient soils can be improved with nutrient banding, but it is difficult to track soil test levels when all nutrients are banded. This is because it is difficult to locate the banding seam when it is time to conduct soil analysis.

Cropping Considerations
Row crop production or solid seeded production is another consideration. Row crops can be grown with banded fertilization that matches row width, but production of solid-seeded crops (or crops with very narrow row spacing – wheat, alfalfa, barley, soybeans, etc.) may be such that nutrients supplied in the band for previous row crop production are not accessible by all plants. This is exclusive to immobile nutrients (phosphorus and potassium).

Other Topics Related to Fertilizer Placement
Does deep banding promote deeper root exploration? This is an interesting question that often comes up. Deeper placement does not promote deeper root growth, but deeper band placement may be more beneficial when surface moisture is running low and the deeper roots are exploring for water and nutrients. In no-till production systems, nutrients are stratified near the soil surface and as long as surface moisture is adequate crops can find adequate nutrients in the upper layer of soil.

Can row crops find broadcast nutrients even though they are planted in wider rows? Absolutely. For example, corn roots can have a diameter as wide as 24 inches and that is more than enough to explore much of the soil. All agronomic evidence to date shows that broadcast applications of immobile fertilizers can be just as effective as band applications under most situations. The plant usually has an extensive root system capable of adequately exploring the soil. Wet, cool soil conditions (or conditions that limit root development) are more likely to benefit from banded fertilizers.

Archive Issue Contributors: 

State Specialists: Anne Dorrance, Pierce Paul and Dennis Mills (Plant Pathology), Mark Loux and Jeff Stachler (Weed Science), Peter Thomison, (Corn Production), Ron Hammond and Bruce Eisley (Entomology), Robert Mullen (Soil Fertility). Extension Educators: Howard Siegrist (Licking), Harold Watters (Champaign), Glen Arnold (Putnam), Roger Bender (Shelby), Steve Foster (Darke), Steve Bartels (Butler), Gary Wilson (Hancock), Ed Lense (Seneca), Alan Sundermeier (Wood), Mark Koenig (Sandusky), Jim Lopshire (Paulding), Steve Prochaska (Crawford), Greg LaBarge (Fulton) and Keith Diedrick (Wayne)

About the C.O.R.N. Newsletter

C.O.R.N. Newsletter is a summary of crop observations, related information, and appropriate recommendations for Ohio crop producers and industry. C.O.R.N. Newsletter is produced by the Ohio State University Extension Agronomy Team, state specialists at The Ohio State University and the Ohio Agricultural Research and Development Center (OARDC). C.O.R.N. Newsletter questions are directed to Extension and OARDC state specialists and associates at Ohio State.