Tuesday, August 15, 2017

Target weeds after small grain harvest

By Jared Goplen, Tom Peters, and Dave Nicolai

waterhemp-in-wheat-stubble
Waterhemp in a wheat stubble field in Ottertail Co., 
Minnesota. Photo: Dave Nicolai
One of the many benefits of including small grains in crop rotations is improved broadleaf weed control and breaking up weed lifecycles. Although freshly harvested small grain fields have a clean look, they often have weeds hiding in the stubble. The most prominent weeds in stubble fields are often late-emerging weeds like waterhemp and other pigweed species that emerged after early season herbicide applications were made. Control escaped weeds now to prevent seed production and weed seed bank replenishment.

Friday, August 11, 2017

Wheat Stem Sawfly Causing Problems in Polk County Wheat Fields

Prepared by Phillip Glogoza, Jochum Wiersma and Ian McRae

As wheat harvest moves northward, we are detecting infestations of Wheat Stem Sawfly in fields in Polk County. Recent storms and strong winds have helped bring these problems to front and center.
  
Farmers have noticed lodged stems, particularly on field margins, where in some cases plants are 100% lodged for 50+ feet from the edge inward. In those cases, the cut stems could be grabbed and picked up in a bundle (Figure 3) and the stubble below was all cut (Figure 4). As we  inspected the interior of these fields, the percent lodging, declined, but there was still evidence of Wheat Stem Sawfly damage.

Infestations have been found in the areas around Crookston and westward toward East Grand Forks. We urge farmers to pay attention to lodged areas of fields to determine if sawfly are a contributing cause of the problem. While driving the combine, lodged stems should be visible from the cab (Figures 1 and 2). 

Infested stems are plugged on the end by the larva for protection from the environment while overwintering (Figure 5). 

Cut stems, if sliced open, reveal the feeding damage and frass left behind by the sawfly larva (Figure 6).



These locations need to be noted so rotation and tillage can be performed to try and break the infestation cycle.


Figure 3. Wheat stem sawfly cut stems were so extensive, the cut stems could be picked up as a bundle on the edge of this wheat field west of Crookston, MN



    


The Following summaries are for the review of Wheat stem sawfly injury, biology, identification, and management:
 





UPDATE: NW MN Soybean Aphid Scouting Summary for July 31 to August 8, 2017

Soybean aphid populations continue to increase in west and south central Minnesota, though we are approaching a time when growth stage, day length and natural controls in those fields are likely to lead to declining populations soon. More fields have been treated, BUT not every field is at threshold and scouting to determine treatment needs is highly recommended. 

Also, be sure to follow up treatment by scouting to determine control success. Some of the fields we have scouted in NW MN show lots of dead aphids. HOWEVER, it is not uncommon to see plants where aphids survived, numbering into the 100's on some of those plants. These are fields most likely treated with a Pyrethroid - Organophosphate premix.

Where we have treated research plots with chlorpyrifos, kill has been very good. The only aphids in those sites have been winged, migrating aphids in the tops of plants. Their numbers and their babies have remained low in number and time should be on our side in those locations.

Reports for southern MN can be found at Southwest Minnesota IPM Stuff Newsletter

Comments from his August 10 report:

"Aphid treatment continues and has expanded to some new areas. Fields in the southern part of the state that have higher aphid populations are related to planting date and moisture. The earlier planted, wetter parts of the state as well as some of the extremely dry areas have lower aphid populations. Remember, there are always exceptions."

Bruce Potter 
UMN Extension IPM Specialist

Tuesday, August 8, 2017

Here are three recent updates, all relating to weed management issues:

Assessing and documenting yield loss due to dicamba injury in soybean
by Jeff Gunsolus, Extension weed scientist

dicamba-injury-soybean
Photo 1. Leaf cupping symptoms of dicamba injury in soybean. Photo: Bruce Potter
As we enter August, the big unknown in fields presenting dicamba injury symptoms will be dicamba’s impact on soybean yield. Unfortunately, due to the sensitivity of non-Xtend soybeans to dicamba, injury symptoms are not reliable indicators of yield loss. The level of yield loss depends on exposure at vegetative or reproductive stage of growth, persistence of injury symptoms, and growing conditions post-exposure.

Monday, July 31, 2017

Pyrethroid resistant soybean aphids: What are your control options?

Bruce Potter (Extension IPM Specialist, U of MN), Robert Koch (Extension Entomologist, U of MN), Phil Glogoza (Extension Educator – Crops, U of MN), Ian MacRae (Extension Entomologist, U of MN), and Janet Knodel (Extension Entomologist, NDSU) 

We are receiving an increasing number of reports of pyrethroid insecticide failures for soybean aphid management from northwest and central Minnesota, and northeastern North Dakota this year. However, many areas of Minnesota and North Dakota still have low, non-yield threatening aphid numbers and scouting should continue to determine when to apply insecticides. 

In this article, we review the insecticide groups used for soybean aphid control (Table 1) and discuss the potential role of and challenges associated with insecticide mixtures. 
We are all familiar with the multistate, researched-based economic threshold of 250 aphids/plant for determining when to apply insecticides for soybean aphid. Waiting until this economic threshold to apply insecticides is KEY for ensuring continued efficacy of current insecticides for soybean aphid. Using the soybean aphid economic threshold for deciding when to apply insecticides will:

  • Prevent unnecessary selection pressure for insecticide resistance; 
  • Save time by reducing the odds of a field needing a second treatment;
  • Mitigate secondary pest problems like spider mites; and perhaps most importantly
  • Reduce production expenses.

Poor insecticide resistance management of a mobile insect like soybean aphid affects not just your farm, but other farmers as well. 

Read more »

UPDATE: NW MN Soybean Aphid Scouting Summary for July 21 to 28, 2017

Soybean aphid populations continue to increase in NW Minnesota. Populations are increasing in the west central and central areas, too. More fields are being treated, HOWEVER, not every field is at threshold. 

Reports for southern MN can be found at Southwest Minnesota IPM Stuff Newsletter

Comments from his July 31 report:
"Treatment of economic threshold populations are now being made in more southerly areas and the general trend is trend is economic threshold populations developing from north to south.

"Parts of Central Minnesota are receiving insecticide applications and sentinel plots at Morris had a fairly uniform 40 aphids/plant early last week. Some fields in parts of the Minnesota River Valley are at economic threshold now.

"As of last week, there were many areas of MN, including most of the SWROC, that still had low aphid populations. Winged aphids can change that quickly.

"The next two weeks will be the critical scouting window for most areas. Remember that most aphids will often be found lower in the canopy now.

"This year, much of SW Minnesota appears to have been colonized by non-local aphids."
Bruce Potter 
UMN Extension IPM Specialist

Sunday, July 23, 2017

NW MN Soybean Aphid Scouting Summary for July 17 to 22, 2017

Soybean aphid populations continue to increase in NW Minnesota. Below is a summary of scouting reports from July 17 to 22. The map reflects increasing numbers and treatment decisions in the NW region. 

Fields scouted in the west central and south central also show increasing numbers from last week. 

Bruce Potter, UMN Extension IPM Specialist, reports fields in those southern areas where populations are approaching treatable numbers that will likely be sprayed this week in southern MN. He adds that some fields have already been sprayed, not many but some. Additional reports for SW MN can be found at Southwest Minnesota IPM Stuff Newsletter prepared by Bruce. Subscribe or follow the link to read his updates.
FRIDAY, JULY 21, 2017

SOYBEAN APHID INFESTATIONS AND REPORTS OF FAILURES OF PYRETHROID INSECTICIDES TO CONTROL SOYBEAN APHID 

Robert Koch (Extension Entomologist), Ian MacRae (Extension Entomologist), Bruce Potter (Extension IPM Specialist), and Phil Glogoza (Extension Educator – Crops)


By now you should be scouting your soybean fields for soybean aphid on a regular basis. Soybean aphid can be found in most fields throughout the state and populations have reached economic threshold (250 aphids per plant) in some fields in northwest Minnesota and have require insecticide application to protect soybean yield. In northwest Minnesota (especially around Norman County), applications of pyrethroid insecticides are failing to adequately control aphid populations in some, but not all, fields.

This is the third year in a row that we have received reports of failures of pyrethroids to control soybean aphid in Minnesota. In 2015 and 2016, field-level failures of pyrethroid insecticides were reported (Figure 1) and pyrethroid resistant populations of soybean aphid were confirmed in Minnesota, particularly in parts of southwest Minnesota. In addition, a resistant aphid population was also found near Crookston in northwest Minnesota in 2016, just north of the area experiencing problems this year.


Figure 1: Locations of reported field-level performance problems of pyrethroids for soybean aphid management. Red indicates areas with more widespread reports of performance problems.

Friday, July 21, 2017

MDA Meetings in NW MN for the Proposed Nitrogen Fertilizer Regulation

MDA extends comment period on proposed nitrogen fertilizer regulation

Public input sought at meetings scheduled in Northwestern Minnesota

St. Paul, MN - The Minnesota Department of Agriculture (MDA) has extended the public comment period for its draft proposal for the use of nitrogen fertilizer in Minnesota. The purpose of the proposed Nitrogen Fertilizer Rule is to minimize the potential for nitrate-nitrogen contamination from fertilizer in the state's groundwater and drinking water. Public comments will now be accepted through Friday, August 25, 2017.

The Dicamba Dilemma:  Facts and speculations

Used with permission by Aaron Hager, University of Illinois

dicamba-injury-soybean
Dicamba injury to soybeans in a southwestern
Minnesota field. Photo: Stephan Melson

Dicamba injury to non-target crops has dominated Extension discussions this week. Non-tolerant soybeans are extremely sensitive to this chemical and damage has been reported in a number of fields throughout the state. The following article by Dr. Aaron Hager at the University of Illinois echoes observations we have been making in Minnesota and summarizes injury symptoms on soybean, possible routes of exposure, and potential yield effects. His article is reprinted in its entirety

Thursday, July 20, 2017

Soybean Aphid Speed Scouting: An option for people who don't like to count aphids

With the focus on soybean aphid scouting, I still like to promote the scouting procedure called “Speed Scouting”. The method speeds up making decisions on whether to treat or not based on the aphid’s population distribution in the field when the treatment threshold of 250 aphids per plant and 80% of the plants with these levels is reached. 
JUST THE FACTS:

A review of the biology and economics behind soybean aphid insecticide recommendations

As farmers and their advisers begin to make soybean aphid decisions for their fields, the timing is right for a fact-based review of what is known about soybean aphid, their effect on yield, and cost-effective management of this pest. 

Soybean Aphid in Red River Valley fields are increasing - Fields at threshold levels being reported

Soybean aphid populations have been increasing and fields with threshold level infestations are being treated. Populations in Northwest Minnesota are greatest in the counties of Norman and Polk, MN and in Grand Forks and Walsh counties of ND. 

Tuesday, July 11, 2017

Meet the newest member of the Extension crops team

On June 30 Angie Peltier joined the University of Minnesota as an Extension educator focusing on crops. She is housed at the Northwestern Regional Extension Office in Crookston and her research and education efforts are to focus on corn and soybean. 

While Angie was born, raised and educated in Wisconsin, she most recently spent close to 6 years as a crops educator working for the University of Illinois Extension at the Northwestern Illinois Ag R&D Center in Monmouth. There her research focus was corn and soybean disease management. 

Angie looks forward to both meeting corn and soybean farmers and other agricultural professionals in Northwestern Minnesota and learning more about their most pressing research and educational needs.

Angie can be reached by mail, phone or email:

Extension Regional Office, Crookston
510 County Road 71, Suite 119
Crookston, MN 56716

Phone: (218) 281-8027

Thursday, June 22, 2017

Small Grain Crop Survey Updates

The newest small grain scouting maps are posted on line.

Wheat: https://www.ag.ndsu.edu/ndipm/wheat 

Grasshopper: https://www.ag.ndsu.edu/ndipm/grasshoppers


Commentary: Small Grains Disease Update 06/19/2017 
                       Dr. Madeleine Smith, Plant Pathologist 

In many areas applications are now being made for late season leaf disease, and Fusarium head blight. 

What's Out There? 

OPTIONS LIMITED FOR RESCUE TREATMENTS FOR IDC IN SOYBEANS

written by:   R. Jay Goos NDSU Soil Science Professor

published June 22, 2017
                 NDSU Crop and Pest Report #8


Reports of iron deficiency chlorosis (IDC) of soybeans are coming in. The unifoliate leaves of soybeans are usually green, being fed by iron reserves in the seed, but as the trifoliolate leaves appear, chlorosis often develops when soybeans are grown on alkaline, poorly-drained soils. Iron is very immobile in the plant, so the deficiency appears first on the youngest leaves. Under severe conditions, the growing point is injured, recovery is limited, and yields are devastated.

Thursday, June 15, 2017

Disease in small grains: When to spray, what to spray, when not to spray!

by Madeleine Smith, Small grains Extension pathologist winter-wheat

Warmer, wetter weather seems to be here at last. As always, the question arises regarding disease risk and fungicide for use against leaf disease and what should I spray? In Minnesota it helps to think of fungicide decision making in broadly three time categories.

Read more »

Wheat Disease Forecasting Web Site

The Wheat Disease Forecasting Web site is available for consulting to assess disease risk for:


This valuable tool is updated with current weather conditions. The models provide a forecast for risk of developing these diseases based on the environment.

The Head Blight / Scab model can also be customized by the user to select for wheat genetics. If a variety is known to be very susceptible, susceptible or moderately resistant, the user can select that condition and get a forecast for risk based on those varietal traits. Numerous, specific varieties can also be selected for their risk forecast 

In addition, there is regular commentary on crop and disease development from:

  • Dr. Madeleine Smith, UMN Small Grains Pathologist 
  • Dr. Jochum Wiersma, UMN Small Grains Specialist 

Both are located at the UMN Northwest Research and Outreach Center, Crookston.

There are numerous other resources provided through the disease forecasting site. Be sure to make this a must visit reference as you begin making fungicide treatment decision in the future weeks.

Friday, June 9, 2017

Lessons Learned from Preemergence Corn Herbicide Research this Spring

Note: The following two videos have been produced by UMN Extension Educators for Crops who are based in Rochester, MN. The message regarding preemerge herbicides is valuable. The two videos presented here provide a review of herbicide performance in corn, the first from May 27, 2017; the second is a follow-up posted June 8, 2017. I hope you find them informative when considering your own preemerge and post emerge herbicide program planning.
Phillip Glogoza, UMN Extension Educator for Crops
Extension Regional Office - Moorhead


by Ryan Miller and Lisa Behnken

Last week, we shared a video on Spring herbicide activity concerns due to cool and wet conditions following preemergent corn herbicide applications (Spring herbicide activity concerns -- May 27, 2017). In the video, we noted that weeds were coming through and wondered if the preemergent herbicides that had been applied would do their job. 

We are back in the research plots in Rochester and checking-in to see how things have been progressing over the past week. In this week's video, we're sharing some interesting observations. 

We have seen differences in the time it takes for different preemergent herbicides to activate, and differences in "reach-back" with different herbicide products. We have also seen the benefit of preemergent herbicides in taking some of the pressure off of postemergence applications by providing at least some of our weed control, and by extending the window to accomplish postemergence applications. 

To view this week's video, Spring herbicide activity progress, visit https://youtu.be/MBdMDr7LIEc. We will be following this trial during the 2017 growing season and providing periodic video updates.


Spring herbicide activity concerns, May 27, 2017

Spring herbicide activity progress, June 8, 2017


If you like content in this format please subscribe to our YouTube channel: 


For other information from University of Minnesota Extension crops, visit z.umn.edu/crops.



Thursday, June 8, 2017

Video: Protecting sugar beets

A Brief Review of Key Soybean Seedling Diseases

by Dean Malvick

Conditions are favorable for soybean seedling disease in many areas. Wet soil, slow emergence, and delayed planting have been favorable for seedling diseases in many areas of southern and central Minnesota. Now as the soil dries and warms up, infected plants may wilt and collapse rapidly due to damaged root systems. 


Problems with seedling disease have been reported from several areas, and more will likely be noted as plants continue to emerge. Given that seedling diseases have developed in some of the well-drained soil at Rosemount, MN, these problems are not restricted to poorly-drained fields this year. This is a good time to scout fields for seedling disease problems.

Wednesday, June 7, 2017

Wheat Crop and Pest Survey Maps


The first maps summarizing current small grain crop stages, disease and insect incidence have been posted. The southern areas of Minnesota represent winter wheat, which is much further developed than the NW HRSW, oats, and the occasional rye. West central and northwest will consist mainly of HRSW and Barley (similar for North Dakota).

IPM CROP SURVEY STARTS for Wheat, Barley and other crops

We have a group of field scouts for the Integrated Pest Management (IPM) Crop Survey for 2017. Field scouts will survey wheat, barley (other small grains, too) and soybean for major disease and insect pests. The purpose of the survey program is to monitor for these economic pests and to provide pest alerts and related IPM strategies for producers and crop consultants. Field pest data that has been geo-referenced with GPS coordinates is compiled weekly and regional maps are created to show incidence and severity of pests in areas of Minnesota and North Dakota.

Maps are now being posted weekly at:


University of Minnesota Extension participates in the IPM Crop Survey in coordination with North Dakota State University Extension Service. In Minnesota, scouts are located in Crookston, Morris and Blue Earth, MN. Phillip Glogoza, Madeleine Smith and Jared Goplen coordinate the MN survey. 

Funding to support these efforts in Minnesota have been awarded by the Minnesota Soybean Research and Promotion Council and the Minnesota Wheat Research and Promotion Council.

Thursday, May 18, 2017

"Yellow Brick Field"

posted by Jochum Wiersma, UMN Small Grains Specialist

The Wizard of Oz's Yellow Brick Road may have been fictional element.  Some springs, solid yellow small grain fields are not.  

Although few reports of early seasoning yellowing have come in to date, Memorial Day Weekend is just around the corner and historically that's often the time one of the causes of early season yellowing is observed.  

Follow this link to an article I posted in 2016 that discusses the most common causes of early season yellowing. 


Barcodes in Wheat, Barley, and Oats?

prepared by Jochum Wiersma, UMN Small Grains Specialist

The beautiful, dry sunny weather with high winds this past week and weekend has allowed many of you to make great strides with planting. Unfortunately this also exposed young small grain seedlings to same conditions. 

Seedlings with the yellow, constricted 
appearance symptomatic for heat 
canker  (photo courtesy of  Byron Fisher)
The daytime heat at the soil surface can and has caused heat canker. The tender young tissue at the soil surface basically has been 'cooked' and this appears as a yellow band that is slightly constricted (Photo 1). As the leaf continues to grow, this yellow band (1/8 - 1/4") moves upward and away from the soil surface. 

If the hot and dry weather last for several days, its is possible to see repeated bands, much like a barcode. The damage is nicely depicted on page 81 of the second edition of the Small Grains Field Guide. Because of the high winds, the tips of leaves may fall over or even break off at the yellow band and give a field a very ragged appearance.

Damage from heat canker is temporary and should not affect further growth and development.

Tall trees catch much wind..or how to avoid the risk of lodging in small grains.

posted by Jochum Wiersma, UMN Small Grains Specialist

The meaning of Dutch proverb "Tall trees catch much wind" doesn't have anything to do with lodging and more to do with the propensity of people to be jealous of those that stand out, but in this context is a nice way to describe the physics off lodging. Simply put, it takes less wind power for a tall crop to lodge, simply because the amount of force needed to bend the stem is less.

Last spring I wrote a summary about the use of growth regulators to reduce the risk of lodging. 

 It can be found here:

Monday, May 15, 2017

Preemergence Herbicides are a Proactive Approach for Weed Management

prepared by Tom PetersExtension Sugarbeet Agronomist, NDSU & U of MN 
and Rich ZollingerExtension Weed Specialist, NDSU

Agriculturalists frequently advocate for use of preemergent herbicides. You heard state Extension Specialists recommend this in presentations during winter meetings and you have read it in trade magazines while you relax at home. Now it is time to put what you have heard and read into action. However, you are not so sure anymore, for some reason. The following evidence is intended to encourage you to apply herbicides preemergence.

Looking for Soybean Growers to participate in a research study on Soybean Aphid Population Levels and Buckthorn Density

We are looking for soybean growers who have 10 or more acres of woodlands or forests that they own and/or are publicly owned and adjacent to their soybean field. 

Soybean aphid has quickly become one of the most damaging pests of soybean in the Great Lakes Region, negatively impacting soybean yields and quality.  There are numerous options for managing soybean aphid ranging from aphid resistant soybean varieties, insecticides, and predatory insects. These treatments focus solely on the field. 

Soybean aphid on buckthorn in the fallHowever, soybean aphid requires buckthorn to overwinter. Buckthorn is a widely distributed, invasive shrub common in forests, woodlands, and hedgerows. There has been little research exploring the relationship between buckthorn density and soybean aphid populations.

The MN Soybean Research and Promotion Council has recently funded a project to explore this topic. The long-term goal of this proposal is to explore treatments methods for controlling buckthorn, decreasing soybean aphid populations, thus increasing quality and yields for soybean growers. 

This in an interdisciplinary project that brings together faculty, Extension educators, and soybean growers to try to answer to the question, “can buckthorn management have economic and ecological benefits for soybean growers?” 

Field crews will sample in both the woodland and the soybean fields. Field crews will set-up forest inventory plots in the woodlands to gain information on the overstory, regenerating seedlings and saplings, and buckthorn density once during the summer growing season. This information will be shared with the landowner. Field crews will use transects to sample soybean aphid populations 2 to 3 times during the growing season to quantify how soybean aphid levels change. This information will be used to test the relationships between buckthorn density, buckthorn proximity, and soybean aphid populations through the growing season.

If you are interested and/or would like additional information regarding participating in the study feel free to call:



      Dr. Marcella Windmuller-Campione 
      612-624-3699 (office) or 
      847-772-5458 (cell) 
      email:    mwind@umn.edu 

We are planning to begin early season sampling in June.

Monday, May 8, 2017

Stink Bug Information now available on-line through the Journal of Integrated Pest Management

Identification, Biology, Impacts, and Management of Stink Bugs (Hemiptera: Heteroptera: Pentatomidae) of Soybean and Corn in the Midwestern United States

Robert L. Koch Daniela T. Pezzini Andrew P. Michel Thomas E. Hunt

J Integr Pest Manag (2017) 8 (1): 11. DOI: https://doi.org/10.1093/jipm/pmx004

Published: 04 May 2017

Monday, May 1, 2017

Farm Business Transitions: Where do I begin?


by Betty Berning

Farm Business Transitions: Where do I begin?

June 6, 2017 
Halstad Legion Recreation Center 
(580 2nd Avenue West, Halstad, MN 56548). 
registration at 9:00 a.m., includes lunch  
concludes at 3:30 p.m.


"Farm Business Transition: Where Do I Begin", presented by the Women in Ag Network, is an interactive program designed to help families understand how to start the transition planning conversation.

Participants will learn about different communications styles; transferring labor, income, management, and assets; retirement considerations for the senior generation; assessing an operation’s financial viability; and goal-setting. Through fun, hands on exercises, families will learn how to apply these concepts to their farm and begin their own transition and succession plan.

The program will be held June 6, 2017 at the Halstad Legion Recreation Center (580 2nd Avenue West, Halstad, MN 56548). The event begins with registration at 9:00 a.m., includes lunch and concludes at 3:30 p.m. The cost for the program is $20; payment can be made day of event via cash or check.

To register, visit http://z.umn.edu/junewagn.

For more information, contact Betty (bberning@umn.edu), Lacy (lwulfeku@umn.edu), or Lindsay (lindsay.mutegi@mn.usda.gov).

Thursday, April 27, 2017

And then it snowed...any free N with that?

by Jochum Wiersma, Small Grains Specialist, University of Minnesota

With the 5 inches of snow or so that fell overnight in Crookston, I was asked earlier this morning how much free N we received with that. Ron Gelderman, former Professor & SDSU Extension Soils Specialist, wrote an article a few years ago for iGrow on how much N is deposited when it snows in early spring. This is a re-posting of his original article.

When it snowed in Brooking, SD in the early spring of 2013 they received 9 inches of snow . This contained the equivalent of about 2 inches of water. The nitrate-N content of the snow was 0.4 ppm while the ammonium-N content was 0.3 ppm. This was equivalent to only 0.3 pounds-per-acre of available nitrogen. Not exactly a windfall of nitrogen, but also very typical nitrogen precipitation concentrations for this area.

The National Atmospheric Deposition Program (NADP) has measured nitrogen and other nutrients in precipitation for a number of stations around the country for over 30 years. The annual level of nitrogen deposits from precipitation will range from about 5 pounds-per-acre on the Western edge of the Corn Belt to 12 pounds-per-acre in the Eastern Corn Belt.

Why the difference? Contrary to common perceptions, most of the nitrogen in precipitation does not come from lightning. There are two main forms of N in precipitation – nitrous oxides (nitrate-N) and ammonium N. About 5-10% of the nitrous oxide forms originate naturally (i.e. lightning) and the remainder comes from human activity, such as emissions from motor vehicles, electric power plants, and industrial sources. Ammonium –N in precipitation can originate naturally from soil microbe activity (about 20%) while the remainder comes from manure or fertilizer (mostly urea forms) emissions of ammonia. The ammonium forms can make up from 25 to 75% of the total N in precipitation. Since most N in precipitation is from human activity, there tends to be higher levels occurring nearest large cities with industrial centers and near agricultural areas.

While the added N in precipitation is not a large contributor to the N needs of our major crops, it can cause large changes in some environments. Some plants can be favored over others by the larger N additions. Acid rain, which is a result of more N and S in rainfall, can cause changes in some freshwater ecosystems as well as harm some forest plant species. For more information on nitrogen deposition check out the National Atmospheric Deposition Program website.

The bottom line? Most snowfalls contribute little to our overall crop N needs, but can significantly influence some sensitive ecosystems.

It's Not All About Herbicides: Three key tactics for managing weeds

Lizabeth Stahl, Jared Goplen, and Lisa Behnken, Extension Educators - Crops

Effective cultivation can 
add durability to weed 
management programs. 
Source: Lisa Behnken
Weed management tools can be divided into three main categories: mechanical, cultural, and chemical. Historically in conventional systems, chemical control options, or herbicides, have been relied on heavily.

Herbicide-resistant weed populations, however, are limiting herbicide options and effectiveness in many fields. Implementing non-chemical options, such as cultural and mechanical control tactics, can help make weed management systems more effective and durable. Understanding and considering weed biology is a key step in developing a successful program. To develop a more robust weed management program, consider the following three key strategies:

Read more at Minnesota Crop News . . . 

Friday, April 21, 2017

Alfalfa winter injury in Minnesota

winter-injured-alfalfa
Photo 1. Severely winter-injured alfalfa in Carver County, 2013. Photo courtesy of Dave Nicolai
Jared Goplen, Lisa Behnken, and Dan Martens


As the weather warms and the 2017 growing season gets rolling, it is time to evaluate alfalfa stands for winterkill and winter injury. There have been numerous reports of alfalfa fields across Minnesota with varying levels of winter injury and winterkill. Many reports are of low areas in the field suffering the greatest damage, with affected field areas ranging from 10 – 40%. Lack of snow cover along with cold temperatures, freezing and thawing in February, and ice sheeting are some possible causes for winter injury and winterkill this year.

winter-injured-alfalfa
Photo 2. Plants from left to right: 1) dead plant with soft root 2) asymmetrical growth, likely will not survive 3) new spring buds growing after winter injury. Plant will likely survive but be slightly delayed 4) Healthy plant with firm root and vigorous growth. Photo courtesy of Dan Martens.

Photo 3. Severely injured alfalfa roots. Photo courtesy of Dan Martens
To get an accurate assessment of winter injury, walk fields now to evaluate how the alfalfa plants are growing. Are all plants actively growing or do some look stunted compared to neighboring plants? Are only potions of the crowns growing? Check areas of the field that are greening up as well as the brown and slow growing areas. It is important to dig up some alfalfa plants to evaluate crown and root health. Healthy plants will be symmetrical, have a number of shoots, and will be off-white and turgid, similar to a potato. More details on evaluating an alfalfa stand, as well as a video tutorial can be found here: 
If the alfalfa field has a substantial area affected, there are a number of considerations to be made. Before making the decision to keep, terminate, or supplement the stand, it is important to evaluate forage and animal inventory as well as the various cropping and replant options. Whether a field should be rotated out of alfalfa or affected areas seeded to a supplemental forage crop will vary by operation. Resources to assist in crop management decisions can be found here:
If alfalfa stands are thin or patchy and termination of the stand is not an option for your operation, there are a number of forage options to seed into winterkilled areas. Information on seeding into standing alfalfa can be found here:
Deciding how to manage a winterkilled or injured alfalfa field can be difficult and will add unexpected costs. However, walking fields, evaluating forage needs, considering options and making a plan now is critical to make a good decision for your farm. The resources provided will help you make the decision to keep or terminate the stand, seed supplemental forage, purchase additional forage, and/or plant new stands of alfalfa. The right answer for you will depend on your specific field and operation. 

Resources related to alfalfa winter kill and winter injury, as well as other forage information can be found at the University of Minnesota Extension Forage website:

http://www.extension.umn.edu/agriculture/forages/