Avoiding Soil Compaction

While I hesitate to say we're in for a late planting year I think it's safe to say that it won't be starting early. Soils are wet and with the temperatures we're seeing, they're cold and drying conditions are not good. At least the early part of the ideal April 20 to May 10 ideal corn planting window is in jeopardy. While the silt loam soils which make up most of Boone County aren't particularly susceptible to compaction, getting in the fields when it's too wet, can still cause significant problems.

The best way to check if fields are dry enough to work is to take a handful of soil and ball it up in your hand. If it sticks together, it’s too wet. If it falls apart, things are probably OK. Make sure to also take some soil from below the surface, down to a foot deep and try this.

Soil compaction can result in a variety of problems. Uneven emergence and early growth rate variability can result in corn and soybeans displaying what I call a “roller-coaster” condition with uneven plant height in a field, particularly in end rows. Compacted soils have reduced water-holding capacity. Poor root system development may lead to nutrient uptake problems or, if the weather turns dry, drought stress. Particularly with corn, the stability of the plant may become a problem. Even if vertical compaction isn’t an issue, planting when it’s too wet can lead to “smearing” of soil in the furrow and sidewall compaction.

The corn roots on the left show compaction while those on the right are normal
If growing conditions are good, moderate compaction often won’t cause many problems. This was the case last year where, as corn planting continued to be delayed, some farmers chose to plant where a field was 80-90% ready and take their chances in wet areas. I saw quite a few fields where sections exhibited sidewall compaction but the weather stayed wet enough that the root system was able to break through the compacted areas. The only real impact I saw was that these areas were a little more susceptible to stalk rots late in the season but not enough to be a major problem. It’s difficult to get a handle on the precise impact of compaction in a given year.

The failure of the root slot to close is often an indicator of sidewall compaction

Farmers can use several strategies to reduce compaction. Some of these, such as no-till, increasing soil organic matter, using cover crops, and improving drainage are longer term in nature. I’ll focus on what farmers can do, other than waiting for soils to dry, to reduce spring compaction.

 

Corn seedling showing evidence of
sidewall compaction

One way to reduce compaction in field work is to decrease the weight over each individual axle as much as possible. Lowering tire pressure will increase the tire “footprint” and spread vehicle weight out over a larger surface area. Using radial instead of bias-ply tires has the same effect. Dual-axle rather than single-axle equipment can also help.

The use of tracked vehicles also helps spread weight out. The key is to have many rollers as weight is greatest under the rollers supporting the tracks.

It's obvious that reducing the number of tillage passes reduces compaction by having equipment run over a field less. However repeated tillage to the same depth can create a tilled surface layer and a layer of underlying dense till which can result in subsurface compaction. Quite often we see armers using a vertical tillage tool or other "light" tillage to loosen up the upper layer of soil so it dries out and warms more quickly. It accomplishes this but it can also result in a compaction layer a few inches beneath the surface.

The most important item to keep in mind is that while there is an ideal planting date for corn, this is only one piece of the yield puzzle, and far from the most important one. Weather conditions such as temperatures and rainfall are more important. Last year’s corn crop was one of the latest planted in history but Boone County Farmers had very good yields. Doing field work when soil conditions aren’t right or “mudding in” the crop can result in problems which may prevent you from being able to take advantage of favorable conditions during the growing season.

2013 Purdue Corn and Soybean Field Trials

I was in a meeting today where someone asked me if Purdue's Hybrid Corn and Soybean Trial results had been published. In the process of switching offices I never posted this information. This may be a bit late as many of you have likely already completed your seed orders however the following link is to the trial results:

2013 Purdue Corn and Soybean Performance Trial Results

Hogs and Corn Price Recovery

Chris Hurt has published an article in the University of Illinois' Farm Doc Daily discussing the prospects for future hog expansion in response to the reduced corn prices which I found very interesting. There are some negatives which may impact the industry's ability to increase the breeding herd, particularly whether porcine epidemic diarrhea virus (PEDv) becomes widespread. In virgin herds this disease has been devastating to young pigs and could result in a delay in national swine herd growth. However the article is positive for long-term corn price recovery.

The same market factors which will influence swine numbers should result in an increase in the cattle herd though it will take longer for this to have an impact on corn prices. A link to Chris's article is below.

Hogs Provide Near $7 per Bushel Corn Value

Cover Crops and Corn Stover Removal

There isn't a lot of corn stover taken off Clinton County fields but there is some. Today I was on a conference call that included Purdue Ag Economist Wally Tyner. Wally has been doing some work looking at corn stover markets and economics and I thought I'd share a bit of this with you.

Dr. Tyner has been evaluating the economics of baling and selling corn stover. I could make a long post out of this but instead I'll hit the highlights and provide a link which you can look over for additional information. The first key point is that in his research he found that around $60 a ton is where it seems to make sense for most producers to sell stover from off the field. Now there are some variables with this and one of the most significant is the distance to market as this substantially impacts profitability. In his research Dr. Tyner is using a removal rate of 33% of all stover produced, about 1.5 tons/acre.

Stover bale. Photo: Greg Roth, Penn State University.

Where things get interesting is when cover crops are factored into the equation. By using cover crops, an additional 1.8 tons/acre of stover can be removed without negative impacts on areas such as soil productivity and erosion. As the cost to plant cover crops is around $40/acre for most mixes, including cover crops with stover removal appears to pay off significantly.

These figures are general and each farmer should run his or her own numbers but it is interesting. If you would like additional information, Purdue Extension Publication RE-7-W, Synergies Between Cover Crops and Corn Stover Removal has much more information including details on assessments of agronomic benefits of various systems as well as the economics. I've included a link to it below.

Synergies Between Cover Crops and Corn Stover Removal

Ear Rots in Corn

The most recent issue of the Purdue Pest and Crop Newsletter has a good article by Kiersten Wise of the Purdue Botany and Plant Pathology Department on identification of ear rots in corn. I haven't heard that there's much of this out there but I think we're all a bit gun-shy after the Aflatoxin issues we had last year. Conditions haven't been perfect for developing any of the ear rots but the growing season has placed some stress on plants and provided conditions where some of these may develop. The keys for managing these are to harvest affected corn as early as possible, dry it quickly and keep it separate from clean corn.

I'd post a picture or two but I'm writing this from my IPad and don't know how. The Newsletter has plenty anyway. I've linked to it below.

September 13 Purdue Pest and Crop Newsletter

Purdue Corn and Soybean Trials

A quick post to mention that the Purdue Corn and Soybean Trial results are available at the following link.

2012 Purdue Corn and Soybean Trials

Grain Quality Issues in Corn

As I'm sure you're aware, 2012 is shaping up as another year where we may encounter grain quality issues with corn. This is always a risk with severe drought stress, particularly if that stress took place during pollination. While Clinton County isn't in as bad shape as many other places, with the recent wetter weather just as harvest is starting up, I'm sure we'll run into it. Every grain buyer in the area, so far as I know, is testing for Aflatoxin, an indication that they've found it in some loads.

Purdue has a web page on this topic with a great deal of information: Managing Moldy Corn

Here are a few of the key concepts as you go into harvest. Keep in mind most of these these (there are a couple of exceptions) won't help with Aflatoxin already present; they help get rid of the Aspergillus fungus which produces Aflatoxin.

One key is minimizing damaged kernels. This corn crop is drying down fast as it's maturing at such an early date. If you think you're at risk for Aflatoxin, make sure you get in the field early enough to keep from having too many damaged kernels and keep fines down to a minimum.

Dry corn a bit more than usual if you plan to store it. If you usually store at 15.5%, think about storing at 14 or 14.5. Also, cool your grain as quickly as possible (an obvious problem in mid-September) without creating moisture issues from condensation. Aspergillus growth is greatly reduced at temperatures below 55 degrees.

Broken kernels and fines generally contain promote fungal activity. If possible, screen your grain before putting it in the bin (or, if you think there's an issue, before taking grain to the elevator). If you can't do this, "core" your bin once it's in storage.

Aflatoxin can cause Human health issues so be careful about breathing in dust. Consider wearing a mask or respirator and change your clothes after handling grain.

USDA's Risk Management Agency has put together a list of Eastern Corn Belt labs which will test for Aflatoxin. You can find that in this publication. Purdue's Animal Disease Diagnostic Lab will also test for it. I don't know why, but they aren't on the list of certified labs in the USDA publication so check with your insurance agent if you're testing for insurance purposes.

If you think you have Aflatoxin, contact your crop insurance agent before you harvest.

Additional Dry Weather in Corn Information

Bob Nielsen put together an article yesterday on his Chat 'n Chew Cafe website with a bit more information on the impact of hot and dry weather on early corn. This adds a bit to my earlier post on dry weather and corn which looked at dryness in and of itself without considering heat impacts.

In essence, Bob is concerned about the impact of the dry weather and in particular some of the heat we've had on the root development of young corn. Not sure there's a lot that can be done unless you have irrigation.

One article I haven't seen is on the accumulative stress of quickly transitioning from periods with nights in the 40's to ones with days in the 90's. If I come across something on this I'll post it.

Impact of Dry Weather on Early Corn

Since the rain last night missed us for the most part, I think it's worth taking a look at how early season dryness impacts corn development. Some years ago (unfortunately this now translates to a few decades ago) when I worked in Nebraska folks didn't worry much about the early season dryness and there was plenty of 7-ft corn which made pretty good yields (this being relative as 150 bu was pretty good). In any case, they generally didn't turn the irrigation on until June, whatever the weather.

Chad Lee and John Grove from the University of Kentucky posted an interesting article a couple of weeks ago on this. In essence, until V6, so long as the plants don't actually burn up, there's little impact from early season dryness. From that point on it starts to become a problem.

Aspects not covered in this article include things like outgrowing potential cutworm damage. Fortunately, while it seems like it would be an ideal year for cutworm damage, I haven't heard of any problems in Clinton County.

Interesting Article on Corn Seeding Rates

Purdue Extension Agronomist and Corn Specialist Bob Nielsen has posted an interesting article on corn seeding rates on his Chat 'n Chew Cafe. I encourage you to take a look at it, particularly if you're thinking about substantially changing your rates in the coming year.

Purdue Corn and Soybean Trials Results Available

The results from the 2011 Purdue Corn and Soybean Performance Trials are available at the link below. We no longer receive a hard copy to distribute so people are asked to access the information online. It is a fairly large file.

2011 Purdue Corn and Soybean Performance Trials

Corn Harvest Issue I: Aflatoxin

We're a little while yet from harvest but getting there, particularly with much of Clinton County corn suffering from a lack of rain. The good news is that many of the fields look better than they appear from roadside "windshield Surveys." Once you get into many (not all, unfortunately) fields, grain fill is better than along field borders.

One of the risks impacting drought-stressed corn is aflatoxin. We've had recent experience with that here so this is mainly a reminder. One tip is if you think this may be a problem, harvest at-risk fields early and make sure corn gets dried down quickly. Aflatoxin multiplies quite rapidly at higher moistures and temperatures but will not when corn is dried down to 13-14% and cooled. Avoid air-drying.

Another implication is insurance. Aflatoxin is a covered loss under many insurance policies, but not after corn is placed in storage. If you suspect you may have aflatoxin, you should contact your insurance agent as soon as possible.

Gary Schnitkey from the University of Illinois has additional information on crop insurance and aflatoxin.

For more information on grain storage issues, see Purdue's page on Managing Moldy Corn, developed in 2009.

Viptera Corn Issue

If you haven't already heard, there's a potentially significant issue with Syngenta's Agrisure Viptera corn. Primarily, China has indicated that they will not accept Viptera corn with the MIR162 insecticidal trait. This creates obvious problems with the possibility of buyers rejecting corn.

There are some sdditional details in this article by Rich Keller which Bob Nielsen posted on his Chat 'n Chew Cafe.

The National Corn Growers Association has put up a Viptera page discussing this issue. Syngenta has also put up a Viptera export information page.

At this point, producers should mainly stay current on this issue and aware of developments. If you've planted this corn you may want to contact your buyer and make sure you won't run into any problems. Hopefully additional information will be forthcoming soon.

Weather Impacts on Corn

Everybody who grows corn knows that the recent hot, dry weather during pollination isn't ideal. The question then becomes how to assess what the impact has been.

The most accurate way is to simply go out and do yield checks by counting ears and kernels. Rather than spell this out here, I'll refer people to Bob Nielsen's article from last October, Estimating Corn Grain Yield Prior to Harvest. In talking to people who've done this already, the general response I'm getting is, "It's not as bad as I was afraid it might be." I know that's not terribly specific but it appears that the corn has been weathering this surprisingly well.

From "drive-by windshielding" there has been remarkably little visible signs of stress in corn, in particular leaf rolling. This has recently started to change a bit in areas of the county which have not received much rain. If you're wondering how leaf rolling equates to yield loss, I'll refer you to an article from July 15 by Roger Elmore and Elwynn Taylor from Iowa State, Corn and “a Big Long Heat Wave on the Way”. In particular, these passages in the final section are interesting:

"By rule-of-thumb, the yield is diminished by 1 percent for every 12 hours of leaf rolling - except during the week of silking when the yield is cut 1 percent per 4 hours of leaf rolling."

and

"The second impact is less obvious initially. When soil moisture is sufficient, as it is for the most part this July, the crop does not have a measurable yield response to one day of temperatures between 93F to 98 F. However, the fourth consecutive day with a maximum temperature of 93 F or above results in a 1 percent yield loss in addition to that computed from the leaf rolling. The fifth day there is an additional 2 percent loss; the sixth day an additional 4 percent loss. Data are not sufficient to make generalizations for a heat wave of more than six days, however firing of leaves then becomes likely and very large yield losses are incurred."

Unfortunately, just in the past few days there has been some lower-leaf firing in corn. As a caution, this goes back to my "drive-by windshielding" sampling method which tends to include quite a bit of end-rows which are generally more compacted and will show more of this.

Late-Season N Applications in Corn

Eric Miller, R.L. (Bob) Nielsen, and Jim Camberato of Purdue Extension have recently offered an article about late season Nitrogen applications when weather or other factors keep you out of the field beyond when is optimum. In brief, the article compares corn with N applied at V7 (7 visible leaf collars) or V15 (a week or two from silking) and a control with only starter N applied. While corn with the V7 sidedress outperformed that with the V15 application, it wasn't by much and both applications far outperformed corn receiving no sidedress.

It's a good article and you should read it through but in essence, even if you're late and have to get creative with equipment, Nitrogen application still pays off.

Twisted Whorls in Corn

Bob Nielsen has provided an updated article on the appearance of twisted whorls in corn. While this can be a sign of plant injury, the growing conditions we've seen the past few weeks can also be a cause.

Note: I'll be gone the rest of this week and all next week and tied up with a GIS program I'm helping teach the following week (this gets us to June 24). I'm not certain how often I'll be able to update this blog during that period, though I'll try.

Delayed Planting Webinar

Last Friday, May 28 Purdue held a Webinar on Delayed Planting Issues. That program has been archived. You can view it at this link.

If you don't have a fast internet internet connection, give us a call and we can set you up with a computer to watch it from here.

Late Planting Issues Post 2

With the rain last night some issues you may have thought about, such as switching from corn to soybeans, are starting to become a reality. Over the last week numerous articles have been written, coming from various sources which I'll link to below.

Assessing Available Nitrogen from Fall- and Spring-Applied Nitrogen Applications - Article posted May 26, 2011. By Purdue Agronomists Jim Camberato, R.L. (Bob) Nielsen, and Brad Joern. We haven't had as many of the gulley-washers Southern Indiana has had but we've still had a fair amount of rain. This article provides information on how to determine if the Nitrogen you've already applied is still available.

Do as I Say, Not as I do - Article posted May 24, 2011. Chad Lee, Grain Crops Extension Agronomist from the University of Kentucky relates his own struggles with the late planting season.

What do We do About the Yellow Fields? - Article posted May 23, 2011. Over the past few years those pretty yellow flowers have come to cover fields in the spring. Bill Johnson and Glenn Nice discuss how to control Cressleaf Groundsel, more commonly known as butterweed. The above link is to a PDF document. For the same information, but not as pretty, this article is also available in the current issue of the Purdue Pest and Crop Newsletter.

Switching to Soybeans? Some Points to Consider - Article posted May 23, 2011. Anne Dorrance and Robert Mullen of The Ohio State University offer some issues to consider if you're thinking of switching crops.

Can Soil-Residual Corn Herbicides Be Applied After Corn Emergence? - Article posted May 20, 2011. In a spring like this one, sometimes things get a little out of order. This is particularly true when so many producers are using commercial pesticide applications. Aaron Hager from the University of Illinois provides some excellent information on which residual herbicides may still be applied postermergence. As always, since this article is written for Illinois, always check to make sure the product(s) are registered for use in Indiana.

Late corn planting won't necessarily mean lower yields Article posted May 20, 2011. Peter Thomison from The Ohio State University discusses how planting date is only one part of the yield equation and summarizes his research into planting date and corn yields.

Prevented and Late Planting Provisions in Crop Insurance - Article Posted May 19, 2011. Gary Schnitkey from the University of Illinois Department of Agricultural and Consumer Economics provides some prevented planting crop insurance information. Keep in mind that the specific information provided here is for Illinois. Always check with your own crop insurance representative about your policy provisions.

Planting Delays and Switching to Soybeans: A New FAST Spreadsheet - Article originally posted April 27, 2011. This is a new Fast Tool from the University of Illinois. As I've previously mentioned, these are downloadable spreadsheets which you input your own information into and use to make decisions. As a caution, the default values you can enter are only for Illinois locations so I'd echo Bob Nielsen's recommendation to completely input your own values and not rely on those already in the spreadsheet.

Lots of Late Planting Information

If you get the chance I'd encourage you to take a look at Purdue Extension Corn Specialist Bob Nielsen's Chat 'n Chew Cafe. Yesterday (May 23) included a bunch of articles from several states related to this planting season.

Late Planting Issues Post 1

Since this blog is just starting I want to include links to a variety of articles and resources related to late planting. Following this initial post, I'll add a new post whenever I receive new information. These posts will be summarized on my current issues page.

Update: "Safe" Hybrid Maturities for Delayed Corn Planting in Indiana - Article posted May 17, 2011. This is an updated article by Purdue Extension Corn Specialist Bob Nielsen discussing corn hybrid maturities appropriate for later planted corn.

Black Cutworm Development May Coincide With Emerging Corn - Article from the May 13, 2011 issue of the Purdue Pest & Crop Newsletter. Purdue Extension Entomologists Christian Krupke and John Obermeyer talk about issues related to Black Cutworm in corn.

Late Planting's Impact on Corn and Soybean Insects - Article posted May 13, 2011. Mike Gray from the University of Illinois talks about how the late planting this spring may impact the development of, and risks from, insect pests in corn.

Replanting Corn: How to Control Plants from the Initial Planting - Article posted May 6, 2011. If you do find yourself needing to replant a field, this article from Aaron Hage of the University of Illinois discusses how to control corn plants from the initial planting. NOTE: This article is for Illinois. Make sure any products mentioned are labeled for use in Indiana.

Profitability Analysis of Late Planted Corn Compared to Soybeans - Article posted May 2, 2011. In this article Greg Halich from the University of Kentucky Department of Agricultural Economics discusses some ways you can check to evaluate whether it makes financial sense to switch from corn to soybeans - obviously, issues such as residual herbicides, conservation crop program, etc., will also play into it.

Farmers should adjust soybean seeding rates in cool, wet spring" - Article posted April 28, 2011. Purdue Extension Soybean Specialist Shaun Casteel discusses issues related to the wet spring and Soybean seeding rates in this Ag Answers article.

Wet Conditions Create Weed Management Challenges in Corn" - Article posted April 27, 2011. This article from University of Kentucky Weed Specialists Jim Martin and JD Green talks about weed management issues resulting from late planting and wet fields.

Estimating Nitrogen Losses from Wet Soils, 2011 - Article posted April 26, 2011. Lloyd Murdock, University of Kentucky Extension Soils Specialist, discusses Nitrogen loss issues.

Early Corn Growth May be Slow, but Don't Throw in the Towel Just Yet - Article posted April 26, 2011. This article from Greg Kruger and Mark Reed Hinze of the University of Nebraska Extension Service discusses the status of corn that's been planted but hasn't emerged yet. You'll need to be careful of applying some specifics to Indiana but it has some good information on why you should be cautious when deciding that a field just isn't going to come up.

Cold Wet Weather and Postemergence, Spike Stage Herbicide Applications in Corn - Article posted April 25, 2011. This article by Bill Johnson and Glenn Nice of Purdue University's Department of Botany and Plant Pathology and Mark Loux from The Ohio State University discusses some issues with early post herbicide applications in corn.

Corn Planting Date is Important, But.... - Article posted, April 21, 2010. This article by Purdue Extension Corn Specialist Bob Nielsen discusses how, while planting date often has an impact on final yield, late planting must be taken in context while considering many other factors.