Several have asked about the potential of nitrogen loss on these saturated soils. This is a difficult question to answer because there are so many variables. First has been the huge difference in rainfall amounts within the area. And then there is the drainage or lack of drainage of certain soils. Saturated soils are where N loss primarily occurs. Losses occur either through denitrification or loss through the tile lines (or in sands, leaching). Denitrification only occurs under anaerobic (without air) conditions. The soil has to be saturated, with no air pore space available before denitrification occurs.

 

The only form of nitrogen that can be lost is nitrate. This is important to remember. The anhydrous or urea or UAN you applied has to be converted to nitrate before losses can occur. These conversions are based mostly on soil temperature. UAN is the quickest to convert (and in fact, 25% is already in nitrate form when it’s applied), anhydrous is the slowest. But within 3-4 weeks of a spring application (April 10-20) conversion of anhydrous had begun. Our estimates of conversion, based upon April 10-20 anhydrous application, are probably around 33% of nitrogen is now nitrate. This is without N Serve.

 

With the warm soil temperatures we’ve had over the past 2 weeks, a rule of thumb is for each day the soil is saturated, you’re likely losing 4% of the nitrate nitrogen. So the question is, how much of the nitrogen you applied is in the nitrate form. And when did soil saturation take place and for how long.

 

If you applied anhydrous April 15, then approximately 33% is now in nitrate form, and is capable of being lost. If you’ve had soils that have been ponded for 3 of the past 7 days, then you can probably assume that you’ve lost 12% of the nitrate nitrogen (4% per day x 3 days). If you originally applied 180# of nitrogen and 33% has converted to nitrate, they you’ve lost about 7# of nitrogen (180# applied x 33% conversion x 12%). So at this point in time, there’s really nothing much to worry about.

 

You can carry out this example to estimate the percent of nitrogen you’ve lost for those portions of fields that have had standing water for longer periods of time. But remember, we didn’t get much conversion up until 3-4 weeks ago, the soils were too cool.

 And also remember, the yield potential of some of these replanted areas isn’t all that high. Especially those areas that still have water standing and are struggling. Perhaps the remainder of the growing season will be better and can make up for a poor early start.

Posted under Illinois

I realize that the timing of what I’m announcing is off a little, but I’d like to schedule several days this summer when we could perform sprayer calibrations on field sprayers for producers. I realize this would be after the spray season has been completed, but there really isn’t time to do this prior to the spray season. And if we can do this prior to storage, you’ll have your sprayer properly calibrated for next years’ spray season.

What I’m proposing is to have 4 or 5 sites, on farms scattered across Adams and Brown counties, where we would set a date to allow neighboring producers to bring their sprayers in to conduct flow rate tests on nozzles as well as inspect for spray patterns. I’m not sure how often sprayers are inspected, but my guess is not too often. This would be an opportunity to have your sprayer properly tested to improve accuracy and efficiency. I’m thinking of scheduling these during July and August.

Scott Bretthauer, Pesticide Safety Specialist on campus, has indicated his willingness to help with this project.

So I’d like to ask for anyone volunteering to host such an event. I would think a morning or afternoon would be sufficient. If you have an interest, please let me know.

Thanks, Mike

 

 

 

Mike Roegge   

University of Illinois Extension

Adams/Brown Unit
330 S. 36th Street   

Quincy, IL 62301  

roeggem@illinois.edu

www.extension.uiuc.edu/adams

Phone: 217-223-8380

FAX: 217-223-9368

Posted under Illinois

 

 It looks like the frost damaged corn has recovered, and quite a bit of NW Iowa has received some rainfall recently. But, I also know of areas that have missed rain and the cornfields planted a little wet are starting to show problems getting those nodal roots established. Rain would certainly help them! This is a good time to dig your young corn plants to evaluate if nodal roots are establishing about 1″ deep, see if they pointing down or horizontally, and notice if the pattern of the root mass is round or flat (sidewall compaction). If you have problems consider why they hap-pened and try to correct that next year. Again – rain can certainly resolve many of these issues.I also know of some soybean fields that have a few beans laying in dry soil – again, a good rain would help. Hopefully those who missed it this week will get some soon!

So, what does the weather for summer look like? I think we have to live it to really know, but ISU Climatologist Elwynn Taylor recently noted that it looks like we might soon enter into a La Nina period. Check out his recent comments here.

Posted under Iowa

I believe we’ve had as many days of 85 degree or higher temperatures this past May, as we did the entire year last year. It’s really made plants respond, with the early corn seeming to grow inches a day.

                The wet weather that we’ve seen the past month or more has also had effects on increasing opportunities for plant diseases on many plants. Among these would be strawberry leaf diseases, fire blight on apples and pears, scab and rust on apples, powdery mildew on bluegrass, plus others.

                About the only action home owners have to deal with these diseases is a preventative application of fungicides, beginning early in the season. The past three springs have been extremely wet, which is very beneficial to many diseases as most pathogens require moisture to spread. Some pathogens prefer cool weather, while others prefer hotter. It just depends upon the specific disease.

                We’ve had several calls of late from individuals who have noticed the terminal ends of their pear or apple tree turning brown. This includes the leaves, branch and any fruit. This is fire blight. Many pears and certain apple varieties are susceptible, and we’ve had excellent conditions the past two years for this disease to spread. The telltale sign is the rather fast browning of the terminal ends of branches. Unfortunately, there is little a homeowner can do, other than prune out those dead areas. However use caution to minimize the potential spread of the disease. Cut back 12 inches from where you see the last discolor on the branch. And then dip the pruners in a 10% chlorox bleach solution to kill any pathogens to prevent spread.

                Strawberry leaf diseases and accompanying fruit rots are abundant as well, again due to the abnormally wet weather. A good fungicide spray program would have prevented many of these concerns. Another good prevention is a straw mulch to prevent the berries from contacting the soil, which carry over some diseases. Some of these pathogens infect the developing fruit very early, while others can infect as the fruit mature.

We have suggested disease and insect spray programs for homeowners for many home fruit plantings. Contact us for more information at 217-223-8380.

Posted under Illinois

Several things to talk about today. One is replanting of corn and perhaps soybean crops. By now, we’ve all determined which fields may warrant replanting. However, I think the later it gets, the more we ought to seriously consider perhaps keeping some of these low population corn fields. The reason is based upon recent research work conducted by Emerson Nafziger, showing percent expected yield based upon plant date and plant population.

                For instance, corn planted prior to the April 23 rains, a remaining population of 20K will likely yield higher than any corn replanted May 30 or later, regardless of population. The same is true for those fields planted prior to Mothers Day (May 6-9). A May 10^th planting of 20K is equal in yield to May 30^th planting at 30K. Of course these are estimates, and are for guidance only. And most fields have areas that show excellent populations and areas that have little to no populations. So replanting of areas rather than entire fields is most likely to occur.

The cost of replanting must also be taken into consideration (any seed charge or partial seed charge, fuel, time, etc) as well as potentially wetter corn at harvest from replanted. And there is no guarantee that the replanted will all emerge.

                A fun part of this exercise might be determining what portions of the field to replant. You all know that 1/1000 of an acre in 30” rows is 17’5”. For 20” corn the number of feet is 26’2”. A more accurate method is to use a measuring wheel, and determine the number of feet needed to count 150 plants. For 30” row, divide that number into 2613.6. For 20” rows use 3920.4 

                And remember, European Corn Borers will be attracted to this later planted corn as well.

Poison hemlock is still present and causing problems for some beef producers. The plant is found all over our area, and cattle will usually not consume it. However, if they do, and especially during the 40-70^th days of gestation, there is great risk to the fetus. I’ve heard from two producers who within the past several weeks, had calves born deformed, and based upon the description of the calves, poison hemlock was probably involved.

Because of the wet summers the past two years, we didn’t expect much problem with poison hemlock, as the cattle would prefer to consume other plants. Unfortunately, small quantities of the plant can cause skeletal defects in the fetal calf. The toxin is also present in any hemlock baled up with hay.

No doubt, the plant is almost impossible to remove from many pastures. But in areas where the plant isn’t well established, eradication now will prevent future problems. In pastures where the plant is well established, managing the grazing periods can certainly help. Scout each pasture to know if poison hemlock is present. Don’t pasture pregnant cows in those pastures when they are most susceptible to the plant. Work on eliminating the plant from all pastures.

Posted under Illinois

Corn and soybean seed costs have escalated to the point where, for many farms, seed is the highest direct cost per acre, or it’s a close second. Just a few years ago, you were paying the same cost per acre for corn seed that you’re paying now for soybean seed.  And while there’s no doubt that newer genetics offers more in terms of production, there’s also no doubt we must manage seed costs more closely today.

                Which leads into the discussion on soybean seeding rate. There is overwhelming evidence to suggest that many producers are planting too many seeds per acre. And at today’s high seed cost, that is increasing your cost of production. Seeding rates of 180-200K were common when drills were used for soybean. We realize that seed depth and efficiency are erratic with drills, hence the need to overcompensate by seeding at high rates. The last few years, with increased seed cost and the use of the row unit to plant beans, the need to fine tune seeding rates is certainly relevant.

                Nearly every Midwestern University has completed soybean seeding studies. And most have spreadsheets to compare the economics of seeding costs using seed cost and selling price as the two variables. Dr. Vince Davis U of I, has authored several articles recently comparing returns, using various seed prices and selling prices. For instance, using a selling price of $10 per bushel, and a seed price of $35 per 140K bag of seed, the optimal seeding rate is 120-150K. Increasing the seed price to $50 per 140K bag decreases the optimal seeding rate to 110-120K.

                Of course, the bottom line is that having a UNIFORM 100K plants per acre (minimum) at harvest is the economic optimum. Many factors can influence seeding efficiency (percent of planted seed that emerge and form a plant). Your task is to determine how many more seeds above the 100K you need to plant in order to successfully have that 100K at harvest.

                Many, including myself, believe that seed treatments are the mechanism to allow you to successfully reduce seeding rates. I don’t believe you can find much data that supports the use of seed treatments to increase yield year in and year out. Rather, seed treatments provide protection to seeds from adverse conditions (plant pathogens, insects, etc.). Selecting the right seed treatment(s) based upon conditions expected on your individual field will allow you to successfully reduce seeding populations while at the same time optimizing performance.

Posted under Illinois

 

In addition to frost, cool soil temperatures, surface compaction, and just plain lousy weather for seedling establishment recently have created some concerns about plant stands. As I dig in fields I can find some seedlings that are emerging later, leafing out underground, are “corkscrewed,” or have damped off before even reaching the surface. A large drop in soil temperature and imbibing cold water as the seedling germinates can have negative effects on some seedlings. See pictures and discussion of these potential problems in this article from the ISU Agronomy Extension Corn Page titled “Early Season Cold Stress.”Again, it will take a couple of warm days for recovery before we can do a decent job analyzing what our plant stand will actually be. Only then can we make a decent decision on replanting or not.

Take a look at the “Replant Checklist” from the Extension Corn site to help make decisions. It has a 5-step process – determine the plant popula-tion, consider stand uniformity if you have uneven emergence, calculate expected yield from the existing stand and adjust for reductions from gaps in the stand, estimate the expected replant yield, and estimate replant costs.

This newsletter, and previous issues from recent years, can be found on-line at:

http://www.extension.iastate.edu/plymouth/info/cropupdate.htm

Only then can you make a reasonably good replant decision. Note, however, that Roger Elmore, our Extension Corn Specialist, has updated his expected replant chart from the one used in the “Replant Checklist” article. There are lots of versions of this chart out there, but this is the one I use, based on Roger’s research and com-puter modeling:

Posted under Iowa

The steady and persistent rains have caused headaches for a number of corn producers. Both for replant and for first plant (and perhaps replanting the replanted acres). The following table developed by Emerson Nafziger, shows expected yields based upon plant date and population. This is an updated yield table based upon more recent research work. You’ll note the table described as from Northern IL, but one of those sites was Monmouth, so I think the numbers are valid.

I don’t know that we’ll all agree with Emerson that 40,000 population will provide a higher yield versus 35,000 but that’s not what we’re using the table for at this point in time. I think what we need to use this table for is to determine how low of populations we may want to retain as the date gets close to June 1^st.

For that corn planted prior to the April 23 rains, a remaining population of 20K will likely yield higher than any corn replanted May 30 or later, regardless of population.

The same is true for those fields planted prior to Mothers Day (May 6-9). May 10^th planting of 20K is equal in yield to May 30^th planting at 30K. Of course these are estimates, and are for guidance only.

The cost of replanting must also be taken into consideration (any seed charge or partial seed charge, fuel, time and assuring the replant will all emerge) as well as potentially wetter corn at harvest from replanted.

 

 

A fun part of this exercise might be determining what portions of the field to replant. You all know that 1/1000 of an acre in 30” rows is 17’5”. For 20” corn the number of feet is 26’2”. A more accurate method is to use a measuring wheel, and determine the number of feet needed to count 150 plants. For 30” row, divide that number into 2613.6. For 20” rows use 3920.4 

And remember, European Corn Borers will be attracted to this later planted corn as well.

 

Mike

 

 

 

Mike Roegge   

University of Illinois Extension

Adams/Brown Unit
330 S. 36th Street   

Quincy, IL 62301  

roeggem@illinois.edu

www.extension.uiuc.edu/adams

Phone: 217-223-8380

FAX: 217-223-9368

Posted under Illinois

 

Early Corn Issues: I have visited a few fields the past couple of days that received significant frost damage about 10 days ago. Almost all of the plants I have observed are elongating and recovering quite well. Most ques-tions have been about “wrapping” of the ends of the plants. The frost-killed tissue is still holding the tips of the leaves together in many cases, and they are not spreading out like normal plants, they are buggy-whipped. But, even yesterday you could see the ends of those shoots are starting to release, and the plants are becoming more normal in appearance. If the shoots have been elongating I believe they will soon unwrap and be just fine. I have noticed a few plants that are not showing signs of continued growth, which is not good news, but fortunately they have been very limited in number in the fields I have observed. There are areas in NW Iowa where heavy rain and hail have also cre-ated

 

marginal stands. Right now we can accept a greatly reduced stand in comparison with the losses from planting corn at this time. If you have to make this decision, review the newly updated “Replant Checklist” prepared by our Extension corn staff at ISU. In emerged corn plants the

 

nodal root is beginning to develop about 1″ below the soil surface. This is our most important root system for the ma-jority of the growing season because the “seed root” doesn’t get any bigger after this point in time. Nodal roots get started at about V-2 (2 leaves with collars), and is almost the sole provider of nutrients for the plant by the V-6 stage. My phone often starts ringing about the V-4 stage with complaints about uneven corn - if we have struggled to get these nodal roots off to a good start. It’s not a bad time to dig emerged plants that have a couple of leaves to review how the nodal roots are getting started, and if sidewall compaction is limiting their establishment. What about

 

spraying frost-damaged cornfields? If leaves were frozen off, don’t forget to count them when staging your corn development. If you are using herbicides than can cause injury after certain stages you need to be careful. Review this article by ISU Extension Weeds Specialist Bob Hartzler on this topic.

Posted under Iowa

Now is the time of the year to begin control of aquatic weeds in ponds and lakes. Controlling weeds now will lead to reduced weed problems later in the summer. Plus, there is a less likely chance of harming the fish if treating now versus in midsummer.

            Some aquatic weed species can increase to tremendous populations if left unchecked, which can lead to unsightly and poorly utilized water uses. But conversely, since they are plants, they are necessary in that they provide oxygen for fish survival.

            There are a few weeds that are common to most area ponds. This list would include: algae, duckweed, watermeal and the pondweed species. Identification of these weeds is necessary before control is considered. Algae is a floating (or barely submerged) weed, with mat like growth, some refer to it as moss. Duckweed is a floating weed, very small, with one to 5 leaflets, and a short root attached. The entire plant is only ¼ inch or so in size. The last floating weed would be watermeal. It is even smaller, at only 1/8 inch or less in size. It resembles floating green seeds, almost like grains of sand. The last weed that I’ll mention is the vine type weeds. There are several that are common, and most are known simply as pondweeds.

            Control of aquatic weeds is warranted if they overtake a pond. Again, since they are green plant material, they do contribute oxygen to water, which is necessary. However, often times, the weeds increase in population to the point where they inhibit pond use. In this case, control should be considered.

Several methods of control are available. One natural control is (sterile) grass carp and these should be considered in every pond. They consume a variety of aquatic weeds; however, will not feed upon mat forming algae, nor duck weed or watermeal. Remember though that as they get older, then consume less, and you may need to restock every 5 years or so. Also as a natural control, don’t expect immediate results (may take a year or so).

Mechanical control can be useful when aquatic weed populations are slight. Pulling, dredging or cutting can work for small areas, but is very time consuming.

Chemical control is an option for many. Control should be initiated before the problem becomes severe (usually midsummer or later). Dying aquatic weeds during the hot summer time period can lead to reduced oxygen availability in the pond, which can lead to fish kill. It’s not uncommon for this to occur. Therefore, now is the time to consider control of aquatic weeds. Also, you never want to treat the entire water body, as it can lead to low oxygen levels, so only treat 1/3 or so at one time. Then wait a couple of weeks and treat another area.

Copper sulfate is a very cheap and effective control for algae. Mixing the crystals in a jug of hot water overnight, and then using that to fill a 2-3 gallon hand sprayer to apply to the pond allows for much better control than simply placing the crystals in a gunny sack and towing behind a boat.

Other products, such as Diquat/Reward, SonarAS, Avast, Rodeo and others provide control of the remaining aquatic weed species. Contact our office or visit the Adams/Brown unit web site for a list of approved aquatic herbicides and their uses.         http://web.extension.uiuc.edu/adamsbrown/agnr.html

Posted under Illinois