Growing Knowledge

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

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.

Preserving land and water

Randy Brown, Ph.D.
Senior Manager – Lead, Regional Agronomists
There are many things farmers are doing to keep their fields and adjacent waterways as healthy as possible and still provide for profit potential. WinField United continues to supply data and tools to help you and other farmers increase yield potential for every drop of water used. In turn, you play a vital role in promoting land and water conservation through various management practices.
 
Nutrient management
Some of the biggest gains not only in sustainability but also in yield potential come from applying nutrients closer to the time crops use them. For example, Answer Plot® trials have shown that strategic application timing can help reduce the financial and environmental costs of applying excess nitrogen.
 
My colleague Ryan Wolf, agronomy manager, also attributes successful nutrient management to strategic tissue sampling. “Well-timed tissue sampling allows farmers to respond with targeted nutrient applications only when needed and not to apply nutrients that are not needed,” he says.
 
Irrigation management
Using water probes in irrigated fields lets you see the amount of water in your soil profile, allowing you to make better irrigation decisions. In the past, we tended to over-irrigate because we didn’t know what the moisture in our soil profile looked like. Much like nutrient management, irrigation management and water probes aid agronomic decision-making so you provide only the amount of water that’s needed at optimal times.
 
Land management
You may use buffer strips, grass waterways, or minimum- or no-till methods to manage soil integrity and nutrient runoff, depending on the part of the country you’re in. Cover crops are another way to capture nutrients and build soil health.
 
Genetics and trait technologies
New seed technologies can also help promote sustainability. “Traits that add herbicide tolerance and insect protection save pounds of pesticides from being applied to crops during the season,” says Wolf.
 
For example, most corn hybrids contain a corn rootworm trait. The less corn rootworm pressure we have in the field, the more plentiful roots we have under the corn plant, which usually translates into higher yield potential. Those roots also capture many more nutrients, so they don’t get into the watershed. The more of a crop we can convert into grain, the more nutrients we remove from the soil profile so they can’t travel where we don’t want them to. 

Jumpstart Plant Nutrition Programs

Jonathan Zuk
Regional Agronomist
Take advantage of precious time before planting to nail down your nutrient management strategy for the year to ensure you’re nourishing plants from the start of the season through all critical growth stages. Following are some ways you can get plant nutrition programs off to a strong start in corn.
 
  1. Ensure proper hybrid placement across your operation. The first step to setting plants up for success is getting hybrids placed right. For example, identifying the right soil type for the root structure a particular hybrid needs is critical to ensuring nutrients can get into the plant. I recommend using hybrid-specific data, available through the Answer Plot® program, including response to soil type (RTST) and response to population (RTP), and placing those hybrids accordingly.
 
  1. Give plants a pre-emergence nutrient boost. Once the hybrid is in the field, help get the plant out of the ground with an in-furrow application of phosphorus with zinc combined with a plant growth regulator. Ascend® plant growth regulator promotes larger roots, which helps more nutrients get into the plant quickly and efficiently, as well as faster emergence and stronger stalks to ensure the plant never has a bad day.
 
  1. Use hybrid-specific data and tissue sampling to plan in-season inputs. To be certain you’re getting needed nutrients into the plant from emergence throughout the vegetative growth stages, combine data on your particular hybrids with tissue samples. Response to nitrogen (RTN) and response to fungicide (RTF) can be used to determine how well that specific hybrid may respond to a nitrogen or fungicide application. If you have a hybrid that’s highly responsive to nitrogen and you’re planning to make a side-dress application, for instance, take a tissue sample to determine if there are other deficiencies like potassium, sulfur or zinc that you can address at that point. These nutrient components really make that nitrogen application become more efficient and help uncover the hidden hunger of your yield potential.
 
Keep in mind all of the tools available to you to make informed nutrient management decisions throughout the season, and work with your local agronomist to put similar practices to work for other crops in your operation.

Follow Best Plant Sampling Practices for Accurate Analysis

WinField United
Agronomy Team
Understanding plant health and nutrient deficiencies begins establishing a baseline for fertility programs. The WinField® United NutriSolutions® 360 system is a season-long fertility management program, including soil and tissue sampling, lab analysis, and product recommendations. Review these guidelines and contact your local WinField® United agronomist for sampling recommendations.
  1. Perform timely sampling. Crops use nutrients differently at various growth stages, so not all crop samples should be taken at the same time. Sampling before crops need key nutrients allows time to adjust fertility plans in-season. Work with a trusted agronomy advisor to determine appropriate timing to acquire the most accurate data.
  2. Be selective in tissue choice. Choosing healthy plant material for sampling is imperative for accurate analysis. Plants under stress from drought, flooding, insect or disease pressure will likely show different nutrient readings than healthy areas of a field. For comparison purposes, stressed areas of a field may be sampled to measure differences in nutrient utilization. The NutriSolutions® 360 tissue testing handbook provides crop-specific tissue sampling timing and protocols.
  3. Collect enough plant tissue. Follow lab directions to ensure the proper amount of leaf tissue is collected for testing. The volume of tissue needed may depend on crop and growth stage. For example, a corn plant sample should be about the size of a softball when bunched up to account for drying that takes place before lab analysis.
  4. Select random plants. Take a big-picture look at the field you plan to sample to get the best results. The goal is to take enough samples randomly throughout the field to get an accurate snapshot of overall plant health. If the field is stressed, more samples should be taken to account for field variability. Avoid sampling plants that have necrotic tissue due to early senescence or disease. Imagery from the R7® Tool can also help identify areas of the field where tissue testing should be completed.
  5. Avoid contamination. Lab equipment is sensitive and will report false results if tissue is contaminated. Avoid submitting samples that may be contaminated by fertilizer residue or soil. If using tools to collect samples, clean them between plants to avoid transferring tissue from one sample to another.
  6. Plan ahead. Sampling at the beginning of the week will allow plenty of time for shipping to the lab. Pack and ship samples according to lab directions; extreme temperatures can negatively affect tissue quality. NutriSolutions 360® sampling requires specific tissue bags to prevent mold formation. Take inventory of your shipping supplies and invest in high-quality materials to ensure your samples arrive at the lab in good condition.

Research Shows Nationwide Plant Health Trends

WinField United
Agronomy Team
Understanding plant health is key to meeting crop yield potential. A study in the Agronomy Journal1 estimates that up to 60 percent of yield is dependent on soil fertility; but soil fertility alone doesn’t tell the whole story. The NutriSolutions 360® system from WinField® United is a season-long plant health management program, including soil and tissue sampling, nutrient analysis, and recommendations to help farmers optimize growing conditions for their crops. More than 410,000 plant samples have been analyzed nationwide over several growing seasons with 92,775 samples taken in 2016, revealing crop- and area-specific nutrient deficiencies that could negatively impact yield potential.
 
Nutrient Trends and Insights
Here are some nationwide trends revealed by NutriSolutions 360® tissue analysis in 2016.
 
  • Corn was deficient in zinc, potassium and nitrogen. Seventy-two percent of the more than 17,500 corn samples taken nationwide were low in zinc. Sixty-eight and 66 percent of corn samples were low in potassium and nitrogen, respectively. Other problem nutrients in corn included manganese, sulfur and boron — all were over 60 percent deficient in 2016 samples.
  • Soybeans lacked potassium. Sampling revealed that 78 percent of the more than 5,500 soybean samples taken in 2016 were low in potassium. Soybean samples also lacked manganese and copper (53 and 42 percent respectively).
  • Wheat exhibited micronutrient deficiencies. More than 90 percent of 2016 wheat samples showed low levels of chloride, which is important for photosynthesis and nutrient transport in wheat. Zinc and/or magnesium levels were low in more than 60 percent of samples. Copper and potassium deficiencies were also common in wheat in 2016.
  • Cotton showed issues with potassium deficiency. Most of the more than 2,500 cotton samples showed low levels of potassium in 2016. Cotton is more susceptible to root and leaf diseases when potassium is limited. Large amounts of the nutrient are needed as bolls begin to develop and fill, so potassium deficiency can also decrease yields. Boron and/or calcium levels were also low in around half the cotton samples received.
  • Alfalfa was short on calcium and magnesium. Calcium deficiency in alfalfa can inhibit root growth and plant development. More than 93 percent of the over 800 alfalfa samples had low levels of calcium in 2016. Low levels of magnesium were also reported.
  • Corn silage nutrient deficiencies included phosphorus, manganese, nitrogen and zinc. Corn silage can remove more nutrients from soil than corn grain, so additional fertilization may be needed on these acres. More than 50 percent of corn silage samples tested in 2016 were deficient in phosphorus, manganese, nitrogen and/or zinc.

Tissue Sampling Can Help Boost Yield Potential
Once deficiency is visible in the field, it’s often too late to correct. Tissue sampling allows insight into a crop’s nutrient status before deficiencies become visible. This allows for corrective action prior to yield loss. Following a solid soil sampling plan and executing a proactive approach to tissue sampling is key to crop success.
 
While nationwide trends in crop health were analyzed and reported, individual field testing is the best way to evaluate nutrient deficiencies. Plant health is dynamic, and nutrient availability is based on localized conditions and management practices.
 
1Stewart, W. M., D. W. Dibb, A. E. Johnston, and T. J. Smyth. 2005. The Contribution of Commercial Fertilizer Nutrients to Food Production. Agron. J. 97:1-6.

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