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

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

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

I have had a few questions from corn producers in neighbor-hoods where localized heavy rains have fallen this spring. Some of these fields seem to have a crust forming. These producers have been questioning me on the use of a rotary hoe. It is very important to check early-planted fields periodically, especially those conventionally tilled with fine soil tex-ture and low organic matter. Timing is important to manage soil crust at the proper moisture conditions. See the ICM News article titled “Pay Attention to Soil Crusting After Heavy Rain Events” by Mahdi Al-Kaisi and Mark Hanna from ISU for a discussion on the timing of a rotary hoe to break up a crust. Don’t wait until it is a thick, dry “road” out there! You can expect stand loss of 1 to 2% if hoeing properly, but that pales in comparison to stand loss protected if a significant crust is forming.

Posted under Iowa

There have been reports of some very early soybean planting. Maybe, for the NW corner of Iowa, we need a little patience? Palle Pedersen, former ISU Soybean Specialist, wrote a very good article about planting dates for soybeans . The recommended starting date for the south-ern 2/3 of Iowa is April 25, including West Central Iowa. For the Northern 1/3 it is May 1. Early planting can give a yield boost due to more branches, maybe more pods, and a longer growing season, if it gets established well. But, the cost of replanting can wipe out advantages. The best responses came in highly productive fields planted under good establishment conditions. Re-member, increased seedling disease pressure and bean leaf beetle damage are risks of planting early.Why do I encourage some patience for beans for the NW counties? Recall that the growing point of a soybean plant is above ground as soon as it emerges, unlike a corn plant whose growing point does not hit the surface until it has about 5 leaves. That makes soybeans much more susceptible to being killed by frost, where corn might only be set back a little.

For examples of frost risk potential I went to the ISU Agronomy De-partment’s “Climodat” site, which has reports that provide some answers to the most common climatological questions they get routinely asked. I looked at the data for the last reported 32 degree temperature from 1951 to 2009 for several NW Iowa towns, and the reported median (middle) date of all the re-ports. The median 32 degree date for Rock Rapids is May 7; Sibley is May 8; for Sheldon, Cherokee and LeMars it’s May 5. Primghar has a median 32 degree date of 4/30, and Sioux City reported April 27. Onawa reported May 1 as the date when half of the years had the last 32 degree temp occurring before that date, and half the years after. My concern, with some early plant-ing and warmer than normal soil temperatures last week, some beans might emerge with quite a bit of frost risk possible for them. Just because we have been warm does not mean that we couldn’t have one cold night in the early part of May. If the beans are still in the ground – great. If not, loss could oc-cur.

Extension Crop Update

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

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

In summary, it is still very early for planting beans. I think good planting dates and conditions will oc-cur, even if we are patient until the first of May for the northern third of this state! A week from now, with good conditions and a good forecast, I would not hesitate. But this week in the NW corner of Iowa I encourage a little patience.

Joel Dejong

Posted under Iowa

Corn Insecticides and Herbicide Interactions?

Posted under Iowa

 ISU Extension is doing a study on the quality of the corn left in the field over the winter. I am looking for 6 to 10 NW Iowa fields where I can collect 24 ears from each and send into Ames for quality and disease analysis. I would need the field‟s location, which hybrid is in the field, and of course, permission to harvest 24 ears from the field. I will collect the samples and ship them. Your e-mail address would be great, too – so I can forward the results from your field. Please e-mail or call if you are willing to let me do that on your farm!

Watch Grain in Storage –

Joel DeJong,

Extension Field Agronomist

Plymouth County Extension

24 1

st St. NWLeMars, IA 51031

Phone: (712) 546-7835

e-mail: jldejong@iastate.edu

Posted under Iowa

Happy New Year??? Welcome to a new year of the Crop Update Newslet-ter. It must be time to get out an issue - I have had a few e-mails asking if I had dropped people from the list. So – here we go! My forecast? Spring will come. Fall soil moisture profiles were almost full in NW Iowa and if we can plant in a timely basis, that is usually a very good sign for yields the next year. But, I know some people have a lot of challenges before that occurs. You never know, maybe we will get above average temperatures for a month soon – like we did in November!

Watch Grain in Storage –

 

Due to the low accumulation of growing de-gree days last year corn test weight is low, and its “shelf life” has been signifi-cantly shortened for many of the bushels in storage. In addition, we harvested more gallons of water than we ever did before – which adds to the challenge. As we begin to warm up the risk increases. I am not an expert on this problem, but I do know that this is not a very safe “savings account” for us this year. Check grain regularly (climb bins safely!). Here are a couple of newsletter arti-cles you might want to review. The first is from Charles Hurburgh at ISU: http://www.extension.iastate.edu/CropNews/2010/0216hurburgh.htm. The second is from the U. of Nebraska “Crop Watch” newsletter: http:// cropwatch.unl.edu/web/cropwatch/archive?articleID=3450012. I keep hearing stories of problems in grain bins – don’t let the story come from you! Glyphosate and Manganese Interactions –

 

Recently I have had sev-eral questions about the use of glyphosate and manganese deficiencies. Some of the ag media have written articles about that recently, and most people quoted are from the eastern United Sates. Research results are very mixed, and it seems that when there is a response to additions of manganese, it occurs in areas of the U.S. where manganese deficiencies are known to occur. We have not seen this in Iowa. Although there has been research indicating Roundup Ready soy-bean may respond differently to manganese than conventional varieties, the ma-jority of research does not support this observation. The best recommendation remains to manage Roundup Ready soybean similar to conventional varieties in terms of fertility management. See this article from Bob Hartzler at ISU for more details: http://www.weeds.iastate.edu/mgmt/2010/glymn.pdf. Joel DeJong,

 

Extension Field Agronomist
Plymouth County Extension
24 1st St. NW
LeMars, IA 51031
Phone: (712) 546-7835e-mail: jldejong@iastate.edu Serving Cherokee, Lyon, O’Brien,
Osceola, Plymouth, Sioux and Woodbury Counties in NW Iowa.

Posted under Iowa

This post was written by admin on March 5, 2010

I often feel that the impact of agri-culture on the economy of the state of Iowa is undervalued. According to an economic analysis from the Economics Department at ISU, done with fund-ing from the Coalition to Support Iowa Farmers, agriculture contributes 26.8% of the total industrial output in Iowa! Jobs including and related to agriculture total 331,880 in this state.To see this series of publications, by county, go to this web site and take a look: http://www.extension.iastate.edu/Publications/PM2023.pdf. Click on your county and review this information. Better yet, print several copies off and share with friends, neighbors, and others in your community so they are reminded of how important agriculture is, too!

Joel DeJong,

Extension Field Agronomist
Plymouth County Extension
24 1st St. NW
LeMars, IA 51031
Phone: (712) 546-7835
e-mail: jldejong@iastate.edu

Posted under Iowa

Each fall, about November 1, I pull soil samples in one foot increments to a depth of 5 feet deep at several spe-cific locations in NW Iowa to analyze how much water is in the root zone for next year. Our good, deep NW Iowa soils can hold about 11 inches of water for the next crop in that 5 foot depth – if we are at field capacity (all the free water has drained out of this soil profile.) These soils are about as good as they get for holding water for the next crop! We use the same locations over and over again because they have been calibrated to help us know how much water the soil at each site can hold. Long term history has site averages for the fall in the 6 to 7″ range, but the last few years have been wetter, so we are now averaging a couple of inches better than that for the last 15 years. The lowest site this fall, west of Sibley, held almost 8 inches of water. Most were around 9 to 10 inches. That was before the last significant rainfall! It looks like our soils will be filled to capacity by the time we start planting next spring – usually a good thing! Of the 20-some inches of rain needed for a crop, we have a good reserve in the bank for this next season, it seems. A good start to 2010.

Joel DeJong, ISU Extension Field Agronomist
24  1st St. NW, LeMars, IA  51031
Phone 712-546-7835, FAX 712-546-7837
Internet: jldejong@iastate.edu

Posted under Iowa