Growing Knowledge

Read the latest insights from our experts as they cover agronomy issues that matter most to you and your operation.

Joel and Jon
Hosts, WinField United
On this episode of the Deal With Yield, hosts Joel Wipperfurth and Jon Zuk discuss the various challenges impacting this year’s harvest, including compaction, common disease pressures like SDS and nutrient deficiency trends in corn. The guys look to answer the question, “Is there a connection between disease and fertility?”

The Deal With Yield is a podcast series covering the issues that matter most in crop production.

5 Tips for Fall Nitrogen Management

Tyler Steinkamp
Regional Agronomist
Nitrogen is a tough nutrient to manage. It can be immobilized, volatilized or leached before plants even have a chance to uptake it. As you consider fall nitrogen applications, here are five tips to make the most of your dollars and time.
 
  1. Watch soil temperatures. Before you apply your fall nitrogen application, be sure the soil temperature is at 50 degrees and declining. Nitrification can take place when soils are above this threshold, making the potential loss over the winter relatively high.
 
  1. Split your applications. With fall-applied nitrogen, you’re many months away from crop uptake. About 75 percent of a corn plant’s nitrogen is taken up before tassel, and 80 percent of that is taken up between V8 and VT. Even with a nitrogen stabilizer, there is a decent potential for loss during those months between a fall application and crop uptake.
 
Spoon-feeding nitrogen throughout the season can favor plant availability. Start with ammonia in the fall, follow that with an at-planting application with your herbicide to get the crop up and running, and finish with a side-dress nitrogen application around V5.
 
  1. Check hybrid response. The amount of nitrogen you apply will vary each year depending on yield goals, weather conditions, crop rotation and the hybrid’s response to nitrogen (RTN). If your hybrids have a high nitrogen response, I’d recommend applying more nitrogen with spring applications. I tend to recommend variable-rate applications in the spring rather than the fall depending on the hybrid’s RTN, the rainfall amounts and the previous crop.
 
  1. Stabilize your nitrogen. Nitrogen stabilizers slow down the conversion of ammonium to nitrate, which is critical to keeping nitrogen in a form that prevents leaching. I recommend using nitrogen stabilizers with every fall application and potentially with early spring applications, depending on the amount of nitrogen applied. Even at planting, you’re 60 days from when the crop will use most of the available nitrogen, so there’s still potential for significant loss.
 
In Iowa, N-Serve® and Instinct® are two popular products used to help stabilize nitrogen. Based on 452 trials from 2010 to 2016, there was an average 8.9 bushel per acre yield increase when Instinct and N-Serve were applied to corn*. In addition, corn trials treated with NutriSphere-N® produced an average 10.0 more bushels per acre versus untreated checks, demonstrating the effectiveness of adding a nitrogen stabilizer to your application.* 
 
  1. Don’t forget sulfur. Without enough sulfur, plants aren’t able to use nitrogen efficiently. For every 10 units of nitrogen applied, a unit of sulfur should also be applied. That can come in the form of elemental sulfur in the fall or an AMS or ATS product in the spring. Elemental sulfur doesn’t release quickly, so I recommend no more than 50 percent of sulfur needs come from elemental sulfur or gypsum. The other 50 percent of sulfur can be applied in the spring with an AMS or ATS product.
 
Keep these tips in mind as you prepare for postharvest nitrogen applications. Contact your WinField United retailer for more information on best nitrogen management practices.
 
* Based on Verdesian Life Sciences and Dow AgroSciences data on file.
NutriSphere-N® is a trademark of Verdesian Life Sciences. N-Serve® and Instinct® are trademarks of Dow AgroSciences.

Can You Spot a Micronutrient Deficiency?

Mark Herz
Agronomist, WinField United
Generally, it’s pretty easy to see when stress has taken a toll on crops. But determining what’s causing unhealthy plants sometimes requires extra detective work. Micronutrient deficiencies, for example, are hard to diagnose based on visual symptoms alone. Here are some tips to help you diagnose micronutrient deficiencies as you scout fields.
 
It might not be insect damage in alfalfa
Boron deficiency is more common in alfalfa than in any other row crop. Since boron is an immobile nutrient in plants, signs of deficiency will show up in new growth first. You’ll often see yellow-reddish leaves near the top of the plant, while older leaves remain green. Boron deficiency is sometimes misdiagnosed as leafhopper damage due to similar plant symptoms. One differentiator is that boron deficiency causes bunched leaves and shorter internodes, whereas leafhopper damage does not.
 
Watch for manganese deficiency in soybeans
Of all the micronutrients, manganese seems to be the most limiting for soybeans. Symptoms of manganese deficiency include yellow tissue between veins on new plant leaves, followed by brown, dying tissue. If the deficiency isn’t corrected, there could be yield loss due to lack of green leaf area. Symptoms of manganese deficiency look similar to other nutrient deficiencies and agronomic problems, so good scouting is key.
 
Your corn might be missing zinc
The micronutrient most likely lacking in your corn crop is zinc. Deficiencies can show up early in the season due to cold, wet soil conditions, or later in the season if the deficiency is severe. Deficiency symptoms generally appear in the newest leaf tissue, since zinc isn’t mobile in plants. To identify if your corn might be suffering from a zinc deficiency, look for yellow or white streaking on the leaves, which may not be uniform across the width of the leaf.  
 
Scout and sample
The best way to definitively diagnose a micronutrient deficiency is by soil and tissue sampling. Micronutrient deficiencies are rarely consistent across a field, so it’s important to target plants that are displaying symptoms to ensure you’re getting an accurate snapshot of your crop’s health. Combine scouting with tissue and soil sampling to help diagnose problems and follow up with appropriate fertilizers in-season as needed, and talk to your local agronomist for help diagnosing micronutrient deficiencies.
 
We’re here to help you with your holistic plant nutrition plan. Next, we’ll explore how to mitigate in-season stress using plant growth regulators and how to pair plant nutrition and seed choices. We’ll continue to dig into all aspects of plant nutrition throughout the year right here on the Growing Knowledge blog, so be sure to check back for more plant health tips.

Do Your Micronutrient Levels Measure Up?

Kyle Gustafson
Agronomist, WinField United
By this time, most farmers have a good idea of how much nitrogen they plan to apply to their crops, but many haven’t given much thought to micronutrient fertilizers. The fact is, insufficient micronutrients can be just as detrimental to crop development as a macronutrient deficiency.
 
Know what plants need
By the time plants show symptoms of micronutrient deficiency, it’s often too late for corrective action. Having a pulse on the nutrient status of your crop throughout the season can allow for fertilization adjustments to mitigate deficiencies. Soil testing, done in conjunction with tissue testing, can provide a comprehensive set of data that can help you better understand nutrient availability and uptake to your crops.
 
The big three
You’d think that since micronutrients are only required in small amounts they’d rarely be limiting. The truth is, changes in field conditions and soil composition can impact micronutrient availability to plants. Zinc, boron and manganese are three common nutrients that farmers in the upper-Midwest may find deficient in their crops. Here are some things to keep in mind as you manage these micronutrients.
  • Cool, wet springs lead to zinc deficiencies. Zinc assists with chlorophyll production in plants, so it’s an important nutrient for harnessing energy for grain production. Deficiencies are common in cold, wet soils and in soils with high pH, free calcium, and low organic matter. Supplemental zinc can be applied a number of ways, including as a seed treatment, included with starter fertilizer at planting or as a foliar application later in the season. 
  • Monitor boron levels in alfalfa crops. Alfalfa uses a lot of boron; therefore, it’s important to survey nutrient levels in an alfalfa crop. Like nitrogen, boron is mobile in soil and is prone to leaching, especially in sandy soils with low organic matter. Boron is important for proper nodule development and overall root growth in alfalfa.
  • Herbicide applications can tie up manganese. Glyphosate can tie-up manganese in soybeans, making it unavailable to the plant. This is more common when crops are grown in organic soils with low pH that are deficient in manganese to begin with.
No “easy button” for fertilization
Unfortunately, there’s no one fertilizer recommendation that works for every situation. In order to evaluate your crop’s nutrient status, you’ll need to get in the field to soil and tissue sample.
Scout fields and continue to tissue-test throughout the season to understand and mitigate nutrient deficiencies.
 
We’re here to help you with your holistic plant nutrition plan. Next, we’ll explore how to mitigate in-season stress in corn and soybeans and how key micronutrients can help protect yield potential. We’ll continue to dig into all aspects of plant nutrition throughout the year right here on the Growing Knowledge blog, so be sure to check back for more plant health tips.

High Management Is a Winner for Wheat

Tiffany Braasch
Master Agronomy Advisor
Kent Pfaff of Washburn, North Dakota, took first place this past December in the National Wheat Yield Contest in the Spring Wheat—Dryland category, harvesting 104.29 bushels per acre with CROPLAN® 3530. To me, more important than achieving this yield is that it also optimized his profit. As Kent’s local agronomist, I wanted to share some of the secrets to his success, which include timely input applications, in-season imagery and tissue sampling data.
 
Fertility crucial from preplant to in-season
Kent starts the season with a soil test to gauge fertility. At planting he applies a micronutrient package that contains zinc with his starter fertilizer. Plant roots, whether they are corn or wheat require zinc in higher amounts in early plant growth. He also treats his seed with Warden® Cereals WR, a product that contains both fungicide and insecticide that protects seedlings from disease and insects early in the growing season. In addition to Warden® Cereals WR, he also uses Ascend® plant growth regulator to help enhance the growth and development of wheat early in the season.
 
Kent customizes a variable-rate nitrogen prescription for each field. This helps him hit his high-end yield goals on the highest-fertility part of his field while backing off on his tougher or less productive areas. He starts with the response to nitrogen (RTN) recommendations for his variety when planning the prescription. Kent variable-rate applies his nitrogen in the form of anhydrous ammonia and applies it side dressed at the same time as seed and starter fertilizer. Like many farmers in our area who use no-till or minimum-till systems, Kent uses this “one-pass” system for his small-grain crops.
 
Follow recommended populations 
Kent followed the CROPLAN® response to population (RTP) scores in determining planting rate, in this case 1.5 million seeds per acre. With other wheat varieties, he may have gone up to 1.8 million seeds per acre; but with CROPLAN® 3530, he optimized yield at a lower planting rate. Managing each variety according to Answer Plot® Program recommendations is key.
 
Maximize acre-by-acre management
In addition to using the R7® Tool to variable-rate apply his nitrogen, Kent is using the R7® Field Monitoring Tool and in-season imagery to track day-to-day performance on all fields in his operation. Early season between third and fifth leaf, he applies herbicides for weed control. At the same time, the use of an insecticide and fungicide helps control disease and insects on the wheat. Another application of fungicide at heading helps control late season disease such as scab. He felt there was yield left on the table by not investing in a flag leaf application. CROPLAN® 3530 has a high response to fungicide (RTF) scores, and we will evaluate this season to determine if another application at flag leaf might optimize his return. Kent says that to him, as a farmer the bottom line is that we achieved a high yield but, more important, improved profitability.
  
Winning with Wheat
Kent and the other National Wheat Yield Contest winners will be honored at the Commodity Classic farm trade show, to be held in San Antonio, Texas, in early March. Congratulations to Kent on this exciting and well-deserved honor. If you want to find out more about the National Wheat Yield Contest, click here. To find out more about how you can increase the yield potential of your spring wheat crop, talk with your local agronomist.

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