Time to Top-dress your Winter Wheat

The winter wheat crop looks like it is off to a good start for 2011, and as I write this the markets are looking good too. We have been fortunate that the snow cover has helped with winter survival. While we have had a few nights of colder weather since our snow melted, these dips do not seem to have caused any serious injury other than the normal leaf burn.


While the wheat in southern Wisconsin has started to break dormancy, the snow a couple weeks ago across central Wisconsin has slowed down the wheat progress compared to normal. Once this snow is off and temperatures warm, wheat in that region will begin greening up also. To tell if your wheat has broken dormancy, carefully wash the roots of a few wheat plants and look for new roots from the crown area of the plant. These roots will be snow white and may be very small, ¼ to ½ inch if the plant has just broken dormancy. Another way to tell that your wheat has broken dormancy is to look at the top two leaves of the plant. If you see a line across the leaves at the point where it was covered by the leaf sheath, it has broken dormancy. The area below the line is the new growth and will usually be a brighter or shiny green color compared to the upper portion of the leaf.

Now is the time to get that spring nitrogen on the wheat as the soil conditions permit. Rates should be based on yield goals for your farm and soil type. I usually like to use dry nitrogen to reduce leaf burn on the new emerging leaves. If you are using liquid nitrogen you will want to try to apply it in a band to reduce the amount of leaf surface that can be potentially injured from the application.

As you are checking for green up in the wheat, it’s a good time to look for the growth of any winter annual weeds that might need to be controlled before they get established and compete with the wheat crop. If you have questions on this or other topics, please contact you local Trelay DSM.

Frost Seeding

Frost seeding has been used for many years, but it is getting new attention in recent years with increased rotational grazing. It is a great way to improve hay or pasture yields or introduce new forage crops into an older, thinning stand. There are many advantages to frost seeding as opposed to tearing up and old stand and re-seeding. The list of advantages include reduced labor and energy, lower equipment investment, a shorter establishment period, and it is a great way to maintain productivity of permanent pastures or hay stands without problems with tillage or soil erosion in spring seeding.

There are a few keys to frost seeding

1) Seed to soil contact is very important for seed germination. One way to help this is to fall graze or clipped to expose the soil. Sod bound pastures are the most challenging because they usually have a thick layer of thatch that covers the soil.

2) Competition from established plants must be controlled. This can be controlled in pastures by grazing frequently in the spring and early summer, but remove livestock when it is down to two inch plant height to allow the light to get to the new seeding. Make sure not to clip lower that a couple inches or the new seeding will not have time to establish an adequate root system.

3) Seed selection and seeding rates. Red clover and birdsfoot trefoil are usually fairly easy to establish with frost seeding. Alfalfa, alsike clover, ladino clover, and white clover can also work well under proper management. One caution is to not seed alfalfa into an established older stand of alfalfa. Alfalfa roots produce autotoxicty that will prevent establishment of the new seeding.

4) Timing is important. For frost seeding to be successful, there must be alternating freeze and thaw cycles, along with spring rains to help incorporate the new seeding. Seeding on top of snow works if the snow is not deep and there is not much slope for water movement during a rapid thaw.

Frost seeding is a low cost way to improve productivity of older pastures or hay stands. Be sure to manage soil seed contact to improve germination of the new seeding. Limit competition of established stands to improve results. Select proper species and seeding rates for your field and situation. For more information on this or other questions click on the following link or call your local Trelay DSM.

Frost Seeding Legumes and Grasses

Assessing your alfalfa stands for winter injury

Now is the time to be looking at your alfalfa fields to make stand evaluations. Even though we had good snow cover this winter, it is still important to look at your fields this spring before you finalize your cropping decisions. By evaluating stands now you will be able to make decisions about what fields to save, what fields are getting thinner and need to be replaced next year, and what may need to be rotated to another crop this year.

The best way to evaluate your stand is to look at the above ground part of the plant first. Check to see how many shoots you have in a square foot, over 55 stems per square foot is ideal, 40-55 means yields may be reduced, and under 40 means the stand is poor and will need to be replaced. Look to see that the shoots are coming from all sides of the crown and not only one side, this would indicate some crown damage and you would want to dig up the roots to get a better look. Check for crowns that may have heaved up over winter or do not show any new shoot growth also.

Be sure to dig some roots of healthy looking plants and check to see that these crowns are healthy also. Healthy crowns and roots will look white to cream colored and will be firm. If the crowns are discolored or soft they may be infected with some root rot diseases that will limit production.

Talk to your Trelay DSM if you have questions or would like help in evaluating your alfalfa stands this spring to make sure you get the most from every acre that you farm. For more information on what to look for to evaluate your stand click on the link below.

Evaluating and Managing Alfalfa Stands for Winter Injury

Sifting Through Latest Glyphosate Info

Recently there has been increased buzz about alleged negative interactions of glyphosate with micronutrients and plant diseases. To date there are many sources of information about this topic in both scientific papers and the popular press. Bob Hartzler from Iowa State University has done a very thorough literature review and discussion of this topic that he presented at the 2010 ISU Integrated Crop Management Conference (Ames, IA). His conclusion from that presentation and the paper he presented were that although these interactions cannot be completely ruled out, there is no data to suggest that there is widespread negative impact on micronutrients or plant diseases.


Purdue University has also published a paper that discusses glyphosate’s impact on field crop production and disease development. In this paper by Purdue University they state “the claims that glyphosate is having a widespread effect on plant health are largely unsubstantiated.” They go on to state “Most importantly, the impact of these interactions on yield has not been demonstrated.” Based on the opinion of Iowa State University and Purdue University, we believe that there is no yield risk with using glyphosate for weed control in Roundup ready Crops. As always glyphosate should be used as part of an integrated pest management system when needed, be sure to follow all label directions when using these products. For more info on these articles, click on the links below.

Iowa State University
 
Purdue University

Nematodes that feed on corn

Nematodes are microscopic worms that live in the soil and water. Many nematode species feed on decaying organic mater, bacteria, fungi, and even other nematodes. But some nematodes, including many that live in the soil, feed on plants and are called plant-parasitic nematodes.


The term corn nematodes would imply that these pests are one uniform group and that they only feed on corn, but this is not correct. There are more than a dozen different species of plant-parasitic nematodes that feed on corn. Most of these also have a wide range of hosts.

Nematodes that feed on corn are not new to the Midwest, these nematodes are believed to have been present since long before corn was a crop in this region. Before corn was a major crop, these pests fed and lived on native plants and prairie grasses

It is common to find these nematodes that feed on corn in almost every field in the Midwest, but populations must reach a certain number called the damage threshold before they are believed to reduce corn yields. This damage threshold varies between species also, for example it only takes 1 sting nematode per 100 cm3 while it would take over 1,000 spiral cause significant damage.

There have been many changes in crop production practices that have been blamed for the increase in nematode damage to corn. These include decrease in soil-applied insecticides, corn frequent cropping of corn, and a decrease in the amount of tillage performed on each acre. While there is no way of knowing that these factors are the cause, we have seen an increase in damage to corn from these pests.

The only way to determine if plant-parasitic nematodes are causing yield loss in your field is to take soil and root sample and have them tested by a qualified lab.

Nothing can be done to minimize the damage or “rescue” a corn crop if nematode damage is confirmed during the growing season. But there are some good management strategies to protect corn from nematode damage in future years. One of these strategies is to use a seed treatment such as Votivo on the seed before planting. Votivo is a very promising new seed treatment that is showing great performance in the Midwest. Please contact you local Trelay DSM for more info on nematodes that feed on corn and what control options are available for your farm.

True Armyworms

True armyworms are showing up in SW Wisconsin and NE Iowa. Armyworms are an occasional pest in the area, but seem to me more numerous than normal is year. Bob Rose and Chris McLimans are both reporting fields with high enough pressures that growers need to take action to prevent stand and yield losses.

This pest will rarely cause trouble in conventional-tilled fields, but growers should be checking reduced and no-till fields. Another likely area of infestation would be fields that had wheat stubble or rye planted as a cover crop that was taken off in the spring. Any kind of ground cover makes a great place for the moths to lay their eggs as they fly up from the south. When the eggs hatch, usually about 7 to 10 days, they begin to feed and will continue for 5 to 6 weeks. At the end of the feeding period they will pupate and reemerge as moths to lay eggs and start the cycle again, we usually see up to 3 generations per year. The second generation will usually appear in July, and is the most damaging.

This insect will usually feed on the leaf margins and will stop at the midrib. Young corn plants have a remarkable ability to recover from the feeding, an ISU study showed that corn in the V7 to V9 stage with 50% defoliation recovered after treatment and only showed a 2-6% yield loss.
Treatment should be considered in V7-V8 stage if larvae are less than 3/4 inch in length, the population is larger than eight larvae per plant, and there is 25% or more defoliation. If armyworms are less than 3/4 inch, they still have about a week to feed before they pupate. At 1 ½ inches, the larvae are about done feeding and treatment is not going to give any economic benefit. There are many common insecticides labeled for armyworm control, you will need to check with your local chemical supplier to see what pricing and availability is for your area.

Sidedressing NH3

Anhydrous Ammonia is a very good source of Nitrogen and also usually the cheapest form available. It is important to make sure you apply the NH3 properly to avoid injury issues.


NH3 is injected into the soil, and usually is the most concentrated within 4” or so of the knife track. In sandy soils or very dry field conditions the concentrated band will be larger because NH3 has a huge attraction to water, and it will move to find available soil water. If you run the knife too close to the rows, you could see root injury from the applicator knife, but there is an even greater risk of burning the roots of the plant from the NH3 itself. See the picture below of root “burn” from NH3.

Once the NH3 ties up with soil water, it moves with soil water to the plant roots and can be taken up and used without causing any injury problems.


Another way NH3 can cause injury is by burning the leaves above ground. In very wet soils the knife will seal the sidewalls so the NH3 cannot move into the soil profile. This will cause the NH3 to move back up the slot made by the knife and escape into the air. Not only will you loose the NH3 that you are applying, it will burn the leaves of the young corn plants. Usually the corn will recover, but the Nitrogen that escapes is lost and does not available for the plant later in the season when it needs it most. It’s always good to make sure soil conditions are good and that you are getting a good seal in the knife tracks when applying NH3.