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Showing posts from May, 2017

Sulfur, Potassium and Boron: Scouting for Common Nutrient Deficiencies in Alfalfa

Early season scouting is imperative to good nutrient management in alfalfa. In Minnesota, the main nutrient concerns lie in sulfur, potassium and boron. Read on for tips on how to scout for and manage these common alfalfa deficiencies.

Sulfur 
In Minnesota, sulfur deficiencies in alfalfa are found in two main areas: 1) sandy soils where sulfur tends to leach rapidly; or 2) soils with low organic matter content that have a limited capacity to mineralize sulfur. Scout for yellowing in the upper leaves and thin stands. The most susceptible areas of the field will be sandy soils with low organic matter and eroded knolls within in the field. 


Preemergence Corn Herbicides Applied in Dry Conditions Followed by Wet and Cool Growing Conditions

Preemergence Corn Herbicides Applied in Dry Conditions Followed by Wet and Cool Growing Conditions

 Are you are concerned with the amount of activity you are seeing with preemergence corn herbicide applications?  This video discusses some of what we are seeing with preemergence herbicide applications in our corn herbicide trials at Rochester, MN.  We will be following this trial during the 2017 growing season, providing periodic video updates.  If you like content in this format please subscribe to our YouTube channel: https://www.youtube.com/user/UMNCrops

Video at:
https://youtu.be/dKX5JY2rvgQ

Herbicide Performance and Crop Injury with Cool Weather

Jochum Wiersma
Herbicide performance and selectivity are a function of how well the small grains and weeds that receive an herbicide are able to metabolize the active ingredient. The ideal temperature for applying most postemergence herbicides is between 65 and 85 F. However, the temperatures following herbicide application will largely determine crop safety as the plant’s metabolism slows during cool or cold conditions. This extends the amount of time required to degrade the herbicide in the small grain plants. Rapid degradation under warm conditions allows crop plants to escape herbicide injury.

Have you lost your N in the past week?

Widespread wet weather and yellow corn has caused concern among Minnesota farmers regarding the status of their nitrogen fertilizer.  Extension Educator Brad Carlson discusses the processes of nitrogen loss from wet weather in context to this past week's weather in the new video, Spring 2017 nitrogen concerns

Additional resources can be found on the University of Minnesota Nutrient management website at  http://www.extension.umn.edu/agriculture/nutrient-management/ and the Extension Crops website, z.umn.edu/crops.

You may also like UMN Extension Nutrient Management on Facebook and follow us on Twitter.

Support for this project was provided in part by the Agricultural Fertilizer Research & Education Council (AFREC).

Are soil residual herbicides necessary in late-planted soybean: What are your options if soybeans have emerged?

Jeff Gunsolus, Lisa Behnken, and Fritz Breitenbach

Figure 1. Emerging soybeans at Rosemount ROC on May 24, 2017. Photo: Dave Nicolai Application of a residual herbicide prior to planting or emergence of the crop is an effective and highly recommended weed management strategy and also a key tool in managing herbicide resistance. Soil-applied residual herbicides are especially important to address tall waterhemp. Tall waterhemp has an emergence period of long duration into the summer and some biotypes are resistant to two to three different herbicide sites of action (SOA). Therefore, it is economically wise to include a soil residual herbicide at the time of planting. However, recent rains have delayed some farmers from getting onto newly planted fields in a timely manner. What are some of our options if soybeans emerged before a preemergence herbicide application was made?

Delayed Soybean Planting? Big Deal -- or No?

Seth Naeve and David Nicolai

Figure 1. Cumulative rainfall over 7-day period ending May 22, 2017 in the upper Midwest. Source: National Weather Service As farmers wait for the weather to clear, planting may be further delayed due to increased soil moisture from the recent rains. According to the May 21, 2017 Minnesota Crop report, topsoil moistures were estimated to be 72% adequate, and 27% surplus while subsoil moisture supplies were rated at 79% adequate, and 20% surplus.

4 key nutrient deficiencies to scout for early in the season

Daniel Kaiser, Extension Soil Fertility Specialist 
Fabian Fernandez, Extension Nutrient Management Specialist

As corn starts to emerge amid cool and wet soil conditions, the potential for nutrient deficiencies is high. Proper diagnosis is the important first step to management. Next is deciding how to manage those deficiencies once they’re started. Here’s a look at four key nutrient deficiencies for the early season and what to do when you spot them.

Nitrogen 

What to look for
Nitrogen deficiencies cause a yellowing in corn leaves, often displayed in a V pattern starting from the tip of the leaf. Because nitrogen is mobile in the plant, the yellowing will show in the older bottom leaves first. Early in the season, nitrogen is required in very small quantities, so a deficiency may not be noticeable unless the soil concentration of nitrogen is very low. Also, since small plants do not have a fully developed root system the nitrogen may be in the soil but in a position that is not availabl…

On-farm research: Trial demonstrates importance of a good design

John Thomas, University of Nebraska-Lincoln; Sara Berg, South Dakota State University; Josh Coltrain, Kansas State University; Lizabeth Stahl, University of Minnesota

Figure 1. Pinto bean planting method comparison. Left: 90,000 plt/A in 30" rows vs. 120,000 plt/A in 7.5" rows (right). The crop season is upon us and producers across the state have been planting and getting their crops established. Farmers are interested in knowing what works best, yields the most, and especially, what is most profitable during these tight economic times. Some may want to compare products or practices on their own farm or look at information from other farms or industry studies.

Tips for conducting on-farm research are outlined in the U of MN Extension fact sheet “How to do research on your farm”. The following is a real-life example that highlights the importance of two key factors (randomization and replication) in conducting useful on-farm research.

Tools for on-farm research

Bruce Potter, IPM specialist

Figure 1. A hypothetical small plot with two treatments (A & B) and four replications of each treatment. Plots appear to be placed in regular rather than randomized order. Paulo Pagliari, University of Minnesota Extension soil scientist, and I recently modified an EXCEL spreadsheet designed to help crop producers and other ag professionals analyze on-farm experiments. This spreadsheet allows you to enter yields for two or three treatments (varieties, pesticides, fertilizers, etc.) with three to eight replications and calculates treatment averages and statistical differences. In addition to yield, the spreadsheet can calculate differences between crop stands, insect, disease and weed control tactics and other variables.

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

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:  Can I Reduce the Risk of Lodging?







Barcodes in Wheat, Barley, and Oats?

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. 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.







Photo 1 - Se…

Using Soil Tests to Effectively Manage P and K

Daniel Kaiser, Extension Soil Fertility Specialist 

With high crop yields in recent years, many producers wonder how much applied fertilizer is enough to hold soil tests at a desired value. Fertilizer ROI depends on the soil’s ability to supply a portion of a crop’s nutrient needs. Phosphorus (P) and potassium (K) follow a diminishing return for each additional pound of fertilizer applied, and since P and K are not mobile in the vast majority of soils, each nutrient can be found in relatively large quantities but only a small fraction of that total amount is available to plants. Here’s a look at some of the most common questions about soil tests and P and K management.


As a farmer, how do I use a soil test effectively to manage nutrients?

Disposing of Leftover Treated Seed

By Lizabeth Stahl, Extension Educator in Crops

A significant amount of seed planted this year will have been treated with a fungicide, insecticide and/or nematicide. For one reason or another, farmers may find themselves with leftover treated seed at the end of the planting season. If you leftover treated seed you want to dispose of, key points to keep in mind:

New stink bug reference for soybean and corn

Fall N availability: Do these scenarios apply to you?

Greg Klinger and Anne Struffert, Extension Educators 

This week we’ve been exploring how the nitrogen cycle and rainfall timing affect fall N availability. Keeping this in mind, consider these real-world scenarios on the likelihood of nitrogen loss from fall-applied fertilizer.



How rainfall timing affects fall N availability

Greg Klinger and Anne Struffert, Extension Educators
Many farmers who fall-applied nitrogen have the same question this time of year: how much of the nitrogen (N) I applied can I count on being there now? The answer depends on the nitrogen cycle and the weather conditions at application time.

This past fall was warm and wet throughout much of Minnesota, with soils staying above freezing into December and above-average precipitation into November. At the University of Minnesota’s Research and Outreach Centers in Waseca and Morris, soil temperatures were not consistently below 50°F until the 9th of November, which is several weeks after the typical.


Why is this important? Because if nitrogen fertilizer is applied when soil temperatures are below 50°F, the conversion of ammonium to nitrate happens slowly- the microorganisms responsible for nitrification are not very active when soils are cold.

Spring rainfall is more likely to leach nitrogen than late fall rains, so if little fertilize…

How the nitrogen cycle affects fall N availability

Greg Klinger and Anne Struffert, Extension Educators 

Many farmers are wondering the same thing this time of year: How much of my fall-applied nitrogen is still available in the soil? To answer that question, we need to consider the nitrogen cycle. Here's a quick refresher.


Three dominant forms of nitrogen exist in the soil: ammonium (NH4+), nitrate (NO3-), and nitrogen (N). Plants mostly take up ammonium and nitrate nitrogen for their growth, while nitrogen contained within soil organic matter is a slow-release source of ammonium in the soil.

Corn and Soybean Planting when it is Cold and Wet

By Jeff Coulter, Seth Naeve, and Dave Nicolai
Unseasonably cold temperatures, wet conditions, and potentially snow are impacting corn and soybean planting in much of the Upper Midwest. The regional climate service partnership between the National Oceanic and Atmospheric Administration and U.S. Department of Agriculture released the following weather briefing for the Upper Midwest on April 27, 2017:
Overall weather predictions:Freezing temperatures in some freeze-sensitive areas during the next 2 weeks.Cool air and soil temperatures, along with rain and/or snow are possible through the next 2 weeks.Temperature outlook for May 3-9:Odds favor below-normal air temperatures.Odds slightly favor much-below-normal air temperatures.Greatest chances in the western Great Lakes to Upper Midwest.Precipitation outlook for May 3-9:Odds favor above-normal precipitation.Greatest chances in the Great Lakes to Mississippi River Valley. Corn planting – Factors for success Soil conditions Avoid tillage an…