Growing Knowledge

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

Season 15, Episode 2: Digging Into Nutrient Deficiencies in Alfalfa and Soybeans

Joel and Jon
Hosts, WinField United
Hosts Joel Wipperfurth and Jon Zuk expand on the nutrient deficiency conversation on this episode of The Deal With Yield. Jon gives a look into 2018 soybean yields and the common nutrient deficiencies seen in fields across Minnesota. Joel talks alfalfa and the decision-making that goes along with managing his favorite crop.
 
Digging Into Nutrient Deficiencies in Alfalfa and Soybeans

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

What We Learned From Analyzing 42,000 Tissue Samples in 2018

WinField United
Agronomy Team
Farmers submitted over 42,000 tissue samples for analysis by WinField United teams this year, and the data shows that crops could benefit from fertilization adjustments made in-season.
 
Nutrient trends and insights
Here are some nationwide trends revealed by tissue analysis conducted by WinField United in 2018.
 
  • Key essential nutrients for corn were limited. Corn plants could have benefitted from in-season nutrient applications based on analysis of over 26,000 tissue samples submitted from across the country. The most common deficiency was zinc; nearly 78 percent of sampled plants were short on the nutrient that aids in chlorophyll synthesis and other metabolic functions. Potassium, nitrogen, manganese and boron were also commonly deficient or responsive.
  • Soybeans had a sharp increase in copper deficiency. Nearly 75 percent of soybeans sampled lacked sufficient copper levels to meet plant health needs. This is up 10 percentage points compared to 2017 and 34 percentage points compared to 2016. Copper is a key nutrient for protein synthesis, cell wall formation and many enzyme systems. A majority of soybeans were also low in potassium based on analysis of over 8,400 soybean tissue samples.
  • Wheat lacked micronutrients. Chloride deficiency was widespread across wheat crops last year, with nearly 85 percent of sampled plants lacking adequate concentrations of the nutrient. Limited availability of chloride can disrupt plant metabolism, including water regulation in cells and plant enzyme activation. Copper, boron, zinc and magnesium were also limited in most wheat crop samples.
  • Cotton was deficient in potassium. Nearly 90 percent of cotton samples fell into the deficient or responsive category for potassium levels in 2018. Potassium is an essential nutrient that is important for fiber development in cotton. Phosphorus and copper were also commonly deficient based on over 1,300 cotton samples submitted for analysis.
  • Alfalfa was short on calcium. Similar to last year, over 90 percent of the more than 400 alfalfa samples analyzed had low levels of calcium in 2018. Calcium aids in nitrogen uptake and nutrient absorption, and it contributes to enzyme activity in plants. The majority of alfalfa samples were also short on magnesium and phosphorus.
 
Timing, source and rates matter
The WinField United sampling database includes more than 475,000 data points that help identify nutrient trends based on geography, soil type and environmental conditions. Based on analysis in 2018, it’s clear that a crop’s nutrient needs vary depending on growth stage, reinforcing the need for tissue sampling throughout the season. It’s not enough to know what nutrients may be limiting plant development. To optimize plant performance, consider the timing, source and rates of fertilizer applications.
 
Tissue sampling, combined with soil sampling, can help you assess crop nutrient availability to fine-tune fertilization applications. Now is a good time to speak with your local WinField United retailer to review sampling data and prepare fertilization plans for next year.

Consider a Back to Basics Approach for Crop Fertility

Jason Haegele
Agronomist, WinField United
Chances are you have some routines and standard processes in place for managing your crop. You’re probably fertilizing, taking care of weeds and choosing the right hybrids for your acres. But, are you keeping plant physiology in mind when you make those decisions? It's not just about applying fertilizer, it’s also thinking about the timing, the rate and source of nutrients to ensure they’re available to the crop exactly when it needs it.
 
Plant nutrition 101
There are 17 nutrients that are required by all plants for survival. Each one promotes a different function in the plant and is derived from a different source, whether that is the air, water, soil minerals or a synthetic fertilizer. If you had the capability to completely remove any one of these nutrients from a crop, it would be unable to perform some function. For example, a plant grown completely without nitrogen would not produce chlorophyll and amino acids essential for proper growth. While it’s critical for plants to have an adequate supply of the essential nutrients for development, not all nutrients are needed in the same quantities and at the same time.
 
Time is of the essence
Agronomists use the term “elemental prominence” to describe the idea that there are certain nutrients that are more important than others at key points during the growth and development of a plant. We know that zinc, for example, is one nutrient that plants are most responsive to early in the growing season when the seed is germinating, emerging from the soil and establishing a young plant. Zinc is important for root growth and enzyme processes in the plant, so it makes sense to apply that nutrient early in the season rather than waiting until later to get the maximum benefit.
 
Putting these ideas into action
Understanding the inner workings of your crops can help you develop a more effective fertility program. Soil sampling prior to planting gives a baseline for determining nutrient levels so you can decide how and when you’ll supplement based on crop needs. Plant tissue sampling can give an indication of how efficiently the crop is using soil nutrients and can allow time for amendments in-season.
 
Much of the focus in the fall will be on phosphorus and potassium, and in certain geographies nitrogen. But there's also a great opportunity to focus on some of the other nutrients, such as sulfur and micronutrients, to provide a strong foundation for adequate plant uptake next year. Talk with your local agronomist to make the most of your crop fertility plans.

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.

Push Crops Through Stressful Conditions With Biostimulants

Jason Haegele
Agronomist, WinField United
During the lifespan of a crop, it’s faced with numerous stressors that can chip away at yield. So what can you do to protect plants from stress? It starts with keeping crops healthy from day one with good management practices.
 
Stay ahead of the season
Start by anticipating potential problems based on current crop conditions and the weather forecast. Scout crops frequently and use technology like the R7® Field Monitoring Tool to track growth stage and crop development. Take tissue samples ahead of key nutrient uptake periods to allow yourself time to make in-season fertilizer adjustments if necessary.
 
Biostimulants can help
In addition to traditional fertilizers, biostimulant additives can give crops an extra boost, especially during stressful conditions. Biostimulants are biologically derived products that can trigger reactions in a plant ranging from stress alleviation to yield enhancement.
 
Voyagrobiostimulant fertilizer by WinField United works well on highly managed corn acres where there is moisture stress prior to application or where moisture stress is anticipated. A foliar application from V4 to V8 in corn is recommended when fertility is adequate and available moisture is low. Answer Plot® research indicates that in areas that had less than 2 inches of rain immediately following a Voyagro application, there was a positive return on investment 93 percent of the time. The average yield response of a Voyagro application under these conditions was 3.8 bushels per acre.*  
 
Toggle® is another biostimulant fertilizer used in corn, soybeans, cotton and other crops. It’s derived from seaweed and enhances root growth, promotes synthesis of antioxidants and improves photosynthesis by increasing chlorophyll production in plants. Toggle works best on acres where stress is known to occur, such as areas where drought and high temperatures are likely or in saline or sodic soils. A foliar application around V5 and again at flowering can offer stress protection in corn.
 
Biostimulants promote plant growth and work best when applied with traditional fertilizer products. Work with your agronomist to develop a fertilization program that works harder to protect your crops during times of stress.
 
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, as well as tips for soil testing. 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.
 
*2015 Answer Plot data, 27 locations across IA, KS, MN, MT, ND, NE, SD, TX

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