News

Rapid Growth Stage in Corn

Early corn planting dates often occur when soils are cool, night time temperatures are low and heat unit accumulation comes at a very slow pace. The first 3 to 6 weeks of a corn plant’s life can be a slow struggle with seemingly little progress but around V-4 permanent roots are becoming established and with increasing temperatures the rapid vegetative growth stage of the crop is quickly approaching.

Corn growth and physiology research performed by Purdue shows some impressive statistics about the crop’s growth potential from V-4 stage through tassel or 21 days after planting to 71 days after planting.

1. Root length increased from 54 miles per acre to 32,000 miles per acre
2. Above ground dry matter weight of the stover increased from 29 pounds per acre to over 9,000 pounds per acre.
3. 73% of the seasonal nitrogen uptake enters the plant along with 74% of the phosphorous and 85% of the potassium.

 

While most of the dry matter weight added during this 50 day period is comprised of carbon, hydrogen and oxygen supplied by the air and water plant growth cannot continue without adequate supplies of essential plant nutrients.  It is important to maintain proper agronomic nutrient levels and monitor these levels with the use of a good soil testing program so the soil will be able to supply the needs of the crop through this rapid nutrient uptake phase.

A good scouting program prior to tassel may reveal visual symptoms of nutrient deficiencies if soils were unable to meet the high nutrient demands during this short window of time and data provided through plant tissue testing will help reveal critical nutrients that may be in short supply.

Data from University of Illinois

Information provided by the University of Illinois suggests that the crop must successfully build a “photosynthetic factory” comprised of approximately 5 tons of dry matter per acre to be well positioned for maximum production that will follow in the reproductive stages of growth.

Know Your Irrigation Water

Irrigation water analysis focuses on the impacts that irrigation water may have on the soil. The repeated application of irrigation water can change the chemical and physical properties of the soil over time. Therefore, the interpretation of data from irrigation water analysis is driven by the prediction of the effects of the irrigation water source on the soil.

The chemical properties of irrigation water drawn from a well is greatly influenced by the bedrock type surrounding the aquifer, as well as the composition of the aquifer itself. For example, an irrigation well drawing water from a limestone bedrock high in calcium will most likely have a high pH, high calcium content, will be high in carbonates, and contain elevated dissolved solids. However, not all limestone is the same. Also, there can be different layers within the bedrock leading to differences in irrigation water quality with the depth of the well.

Good long-term management of irrigated land needs to take irrigation water quality into consideration. The repeated use of irrigation water with a high concentration of a specific element or compound can lead to accumulations and potentially excess levels of that element or compound in the soil. Depending on the specific material, this could lead to reduced plant health and/or yield over time.  For example, the repeated application of irrigation water with high calcium carbonates without acid injection treatment can lead to plugging of irrigation equipment and the continual increase in soil pH over time.  The increasing soil pH, if left unmanaged, could become high enough to limit the availability of plant nutrients, as well as lead to other negative management challenges. This is of greater concern if the same bedrock influenced the formation of the soil. In this example, the soil would also be inherently higher in carbonates and have a higher pH before additional calcium carbonates are added to the soil through the irrigation water.  

For sound management of irrigated land, irrigation water analysis is a crucial tool to identify possible issues associated with the irrigation water source, and to define proper techniques to mitigate those issues. However, proper management also requires routine soil testing to monitor the impact irrigation water has on the soil over time to ensure the overall irrigation water management is working.

Sampling for SCN

Interest has been steadily growing in soil sampling for Soybean Cyst Nematode (SCN), and with good reason. SCN continues to be the leading yield loss pathogen in U.S. soybean production. The impacts of SCN continue to grow as the pest continues to spread throughout the soybean production acres of the U.S. The map below shows how SCN has spread from a small isolated area along the Mississippi River in 1957 to the last survey in 2014. It is particularly concerning how quickly the area affected has expanded since 2001.

https://www.soybeanresearchinfo.com/diseases/scnpics/SCN_dist57_14_lg.gif

The spread of SCN through the Great Lakes region, increased focus on high yield soybeans, the potential link of Sudden Death Syndrome to plants experiencing SCN feeding, and new products on the market showing some level of SCN control has increased the interest in sampling for SCN.

Sampling for SCN can take two forms: a diagnostic approach to identify a crop issue, or a proactive management approach looking at whole field SCN levels to determine future planned management activities. Each of the approaches have different sampling procedures and interpretations, but utilize the same laboratory procedures. A N-CYST test from A&L Great Lakes Laboratories provides a count of both SCN eggs and adult SCN cysts which are used to identify treatment and management thresholds.

A diagnostic approach is used when a yellow and stunted area of a soybean field is suspected to have elevated SCN populations leading to the visual symptoms. In this case, soil sampling for SCN will be targeted to verify the presence and amount of SCN in the affected area. While visual inspection of the roots can note the presence of SCN, it does not quantify the population. SCN may be present, but at populations below the threshold at which injury should occur. To properly sample for SCN, 8 or more soil sample cores should be taken 6 to 8 inches deep in the affected area. If the field has a history of elevated SCN levels it may be advisable to take a sample from a portion of the field not showing visual symptoms to collect comparative data. Place the soil cores in a clean plastic bucket. Once all of the cores are collected, thoroughly mix the sample and place two cups of soil into a sealed and labeled soil sample bag or plastic bag. The samples should be sealed to avoid moisture loss and protected from extreme temperatures; do not freeze or refrigerate, or leave in the dash of the truck on a summer day. A cooler can be very helpful for sample storage during collection. If the samples are handled in such a way that lead to cyst death, the adult counts will be negatively impacted. Ship or deliver to the lab a quickly as possible.

As a tool for proactive management of SCN, whole field samples can be collected to identify average SCN populations across a field or region of a field. This method is helpful in identifying fields that need additional management to address SCN, but populations can be underestimated when sampling a large area, because small areas of very high SCN populations can be diluted with unaffected areas. Whole field sampling for SCN mirrors traditional whole field composite soil fertility samples. Take samples late in the growing season after flower through harvest. Collect a minimum of 10 to 20 soil cores to a depth of 6 to 8 inches, while walking in a zig-zag pattern across the field, and place the soil cores in a clean plastic bucket. Once all of the cores are collected, thoroughly mix the sample and place two cups of soil into a sealed and labeled plastic bag. Again protect the samples from drying out and from extreme temperatures while shipping the samples to the laboratory as quickly as possible.

For any additional questions regarding SCN sampling, feel free to contact your A&L Great Lakes Laboratories agronomist or call the laboratory directly at 260-483-4759.

Making Sense of Soil Nitrate and Ammonium Values

We have been fielding a wide variety of questions around soil nitrate and ammonium soil test levels. Many soil nitrogen levels from fall manure applications are indicating the need for supplemental nitrogen. Wet weather, and brief periods of warm weather, have led to nitrogen loss. When manure was applied later in the spring, the results are looking much more positive, often above the 25 ppm nitrate level that is universally considered adequate to produce a corn crop. There are some soil tests near or just below the 25 ppm nitrate threshold and may need to be reevaluated later in the season for a possible late season nitrogen application. This re-evaluation later in the season should allow time to evaluate nitrogen loss due to weather the remainder of the season and provides the opportunity to determine a realistic yield expectation. More information on interpretation of Presidedress Soil Nitrate Testing (PSNT) for Corn can be found on our website.

The traditional PSNT interpretations can be challenging to relate to. Providing that the samples were collected to a depth of 12” there is a simple “rule of thumb” to help make sense of a soil nitrate and ammonium value. Add the ppm of the nitrate and ammonium together and multiply by four. This is a relative nitrogen application rate available in the soil at the time of sampling. For example, sample 1 below would be 20 ppm nitrate + 10 ppm ammonium = 30 ppm x 4 = 120 pounds nitrogen. More on this concept can be found at https://www.agry.purdue.edu/ext/corn/news/timeless/AssessAvailableN.html.

While the traditional PSNT interpretations assume a continuous release of nitrogen to the soil from the mineralization of manure organic materials during the growing season, this calculation helps relate to a nitrogen level in the soil today. The difference between the estimated pounds of nitrogen, and a total nitrogen program for the season, is about the same as the PSNT interpretations would recommend.

Spring 2020: Heating Up

Some areas of the corn belt experienced good field conditions in late March and early April that allowed for fertilizer applications, burn down spraying, and other field preparation. In many areas, conditions were very tempting for planting but the temperatures and the calendar were a concern.  In the southern part of the region, some corn acres were planted during the first week of April with additional acres planted about two weeks later. Just as spring looked to be well on track, along came the cold nights in early May with widespread freeze damage for many growers.

If we take a closer look at the development of a corn crop, assuming a planting date of April 20 and moving to the present date of May 25, average growing degree unit accumulation for central Indiana would be about 11.8 units/day. Over that time period, we would be approaching a total of 413 units. In 2020, according to the University of Illinois heat unit calculator, Hendricks County Indiana near Indianapolis has only received 4.2 heat units/day during that period and we are now at a deficit of 265 heat units compared to the 30 year trend line.

The following diagram tracks heat unit accumulation in 2020 on the black line compared to the 30 year average plotted in purple.  The data would indicate corn planted April 20 at this location emerged in about 17 days on May 6 and at the present time crop development is tracking about 15 days later than normal.  The delayed emergence might have caused some minor stand loss and the reduced leaf area, and  transpiration rate. In addition, reduced root mass due to the delayed development may limit nutrient uptake rates until temperatures return to a warmer seasonal pattern.  Mineralization of soil organic matter will occur at a slower rate and subsequently availability of mineralized nitrogen, sulfur, and boron may be observed.

Post emerge herbicide applications may be pushed a few days later than normal and weed development will also be delayed by the cooler temperatures, and extra care will be needed to properly time these activities for best weed control.  Rapid growth phase of the crop and maximum nutrient uptake may be slightly later than normal, depending on temperatures moving forward.

The next diagram shows how the crop might progress with a return to normal 30 year trend GDU accumulation.  Warmer, sunny days ahead may allow the crop to return to a more average rate of development.

University of IL Growing Degree Calculator

Collecting Plant Tissue Samples

We put a great deal of effort and resources into ensuring quality with our analyses here at A&L Great Lakes Labs. We want the data that you receive from us to be of the highest quality so that it is of the most benefit to you and your operation. However, quality analysis is only one piece of the puzzle. Good quality data begins with a good quality sample, and how the sample is collected and handled after collection goes a long way to ensuring its usefulness.

Plant tissue testing can be a very valuable tool to use in your fertility program. However, there are a number of guidelines that should be followed to ensure that this information is useful to you.

1. Sample the correct part of the plant. The interpretations of plant tissue analysis have been developed based on a particular part of the plant, and that part can vary based on the crop and growth stage of the crop. For more information, please refer to our Plant Analysis Sampling Guide, available from our website.

 

2. Collect enough sample for analysis. The amount of sample to collect can also be found in the Plant Analysis Sampling Guide. The amount of material listed is generally a guideline to help ensure that the sample is representative, but is not a minimum requirement.

 

3. If the samples are extremely dirty, shake off any excess dirt or gently wipe the samples off. Washing of samples is generally discouraged, as this can affect the potassium (K) content of the material. If you do choose to wash the samples, do so soon after sampling and before shipping to the lab to reduce these losses as much as possible.

 

4. Place the samples into PAPER bags, never plastic! Paper bags allow the samples to breathe and preserve the integrity of the sample.

 

5. Include a completed Corn and Soybean Plant Submittal Form or Plant Tissue Submittal Form (for all other crops) with your samples. Complete the form as thoroughly as possible to ensure that your report is accurate. Be sure to indicate the plant type and growth stage on the submittal form.

 

6. Pack the samples loosely into a box, and ship them to the lab as soon as possible. It is generally best to ship the samples so that they arrive at the lab within 2 days (samples shipped via UPS Ground generally arrive within two days when shipped from anywhere in the Great Lakes region). It is best to ship samples Monday-Wednesday, to reduce the possibility of samples being in transit over the weekend.

If you have any questions about plant tissue analysis, please contact your A&L Great Lakes regional agronomist or call the lab at 260-483-4759 and we will be happy to assist you!

World Fertilizer Supplies in 2020

News is beginning to spread about possible crop production input chain disruption for the 2020 growing season. Looking to fertilizer inputs, those imported materials take weeks to months to reach US producers. Much of that material is ordered for delivery before spring through the early spring planting season. A large portion of the material for the 2020 spring season is already in the domestic manufacturing channel, in the transportation/import/export channels or has been delivered. While fertilizer supplies may become tighter as spring progresses, supply should be able to meet normal spring fertilizer demand.

With this logistical support for spring supply, it could also possibly impact the fall fertilizer supply. Due to needed lead time, the fertilizer production for the fall of 2020 starts months before delivery at the mine, so that the product can work its way through the mining, manufacturing and transportation channels to reach U.S. farmers in the fall of 2020.

China is the global leader in nitrogen production at 40 million tons in 2019, with Russia in second with 15 million tons, and the U.S. in third at 14 million tons. The U.S. has increased its nitrogen production by over 40% since 2015 thus reducing our imports of nitrogen to only 12.5% of 2019 consumption.

China is also the world’s largest phosphate producer. China’s 2019 production was 110 million tons, followed by Morocco at 38 million tons, and the U.S. falls in third with 23 million tons. The U.S. farmer is somewhat protected since the U.S. imports less than 10% of the annual phosphate consumption primarily from Peru (79%) and Morocco (20%). Covid-19 disruptions in manufacturing and transportation within the U.S. and globally may decrease world supply in the coming months, but not due to import interruptions.

Canada is the world's largest potash producer at 13 million tons in 2019. Belarus and Russia are close in proximity and production of both at 7 million tons. China comes in at 4^th with 5 million tons and the U.S. comes in a distant 10^th place in potash production at 0.5 million tons. The U.S. imports over 90% of the domestic potash consumption. While 81% of out imported potash comes from Canada, which logistically is easier than importing phosphate from South America or Africa, we are importing a significant portion of our potash.

For nitrogen and phosphate, the U.S. is self-sufficient and retains most of the material for domestic consumption. The U.S. farmer relies heavily on Canada for potash production, but this relatively close import mitigates some of that risk. As we have seen with disruptions in the food supply chain in the U.S. and globally, there is a potential for disruptions in fertilizer supply for the fall 2020. 

As more agronomists and producers move to soil sampling more frequently and often a season ahead of fertilizer application, these practices may become even more advantageous as it allows producers and suppliers to estimate fertilizer needs and procure those products months before they need to apply. Fertilizer pricing and sourcing are just two of the many advantages to sampling in advance of applications. Contact you ALGL agronomist to discuss additional benefits.

(data source – U.S. Geological Survey, Mineral Commodities Summaries, January 2020)

Utilizing Nitrate and Ammonium Sampling to Manage In-Season Nitrogen Applications

Nitrate losses through leaching and denitrification, and the soil’s ability to supply nitrogen through mineralization of organic matter, are probably the two largest variables in selecting the best nitrogen application rates for corn production.  Temperature and moisture are the controlling factors that drive these processes and, while the weather is beyond our control, nitrate and ammonium soil testing are valuable tools that can guide us to better management decisions.  When compared to traditional soil sampling for nutrient content please consider some critical process changes that need to be made when analyzing for nitrate and ammonium.  Soil cores must be taken at a depth of 0”-12” and it is best to collect 15-20 cores per sample because of the higher variability of nitrogen content across the landscape.  The samples must be shipped to the lab as quickly as possible (1-2 days) for best results.

Results are normally reported as NO3-N (nitrate-nitrogen) and NH4-N (ammonium-nitrogen) measured as a concentration in parts per million.  While these samples have been analyzed for the nitrate and ammonium compounds, the results have been converted by calculation to reflect the actual nitrogen content of each nitrogen form, and they can be added together to estimate the combined nitrogen.  Please remember that the results are based on a 12” sample and must be multiplied by 4 to estimate nitrogen in pounds per acre.  Additional samples can be collected from deeper in the soil profile (12”-24” and 24”-36”) to track mobile nitrate which can leach downward with soil moisture.

Jim Camberato and Robert Neilsen with Purdue Extension have calculated the theoretical nitrogen levels that can be expected based on fertilizer nitrogen applied.  These values are a good starting point when estimating losses that may have occurred prior to the nitrate and ammonium soil sampling date and can be used to fine-tune side-dress target rates.

 

                

1. Camberato, R Neilsen 2017

https://www.agry.purdue.edu/ext/corn/news/timeless/AssessAvailableN.html

Monday morning quarterbacks can usually do an admirable job determining the ideal nitrogen rate for last year’s corn crop but estimating nitrogen losses, soil nitrogen mineralization, and dialing in the perfect nitrogen rates for the current crop has many challenges.  Soil nitrate and ammonium testing can be a useful tool to aid in these decisions.

The Story a Wear Mark Tells…

Social distancing is a foreign concept to many in sales. Like most salespeople, I am used to shaking hands, and hopefully being warmly greeted when walking into an office or place of business. I find this lack of direct personal interaction odd and unfamiliar.

 

 

While I cannot visit a customer in person, I find myself thinking from time to time about the mechanics of an in-person sales visit. While it may be more intuitive to some, all successful salespeople observe the environment around a direct personal interaction with a client or fellow industry member. We notice pictures of family, objects that may indicate personal interests or logos that show brand allegiance.  Sometimes, even the smaller details have a story to tell. I took a break from the doldrums of the computer today and noticed wear marks on my computer mouse where the entire outer surface of the left mouse button is worn away. Even a worn mouse button has meaning; a story to share.   

 

 

Here at ALGL, our sales staff is also the agronomy staff. While this group of individuals has a very diverse range of experience and knowledge to support the customer in the use of our data, this staff is also a key part of our data quality. We aim not to turn soil analysis results the next day; the day after the soil is analyzed at ALGL the data is in the hands of our quality control department for a final review, and then in the hands of the agronomy staff for a second review. The agronomy staff is looking at the final reported data from an application perspective.

Those wear marks came from this member of the agronomy staff clicking through 100’s of reports a day. Like the rest of the agronomy staff, I am trying my best to ensure the data meets the expectations of our customers that I have the honor of getting to know personally when I fulfill the dual role of agronomist and salesperson.

Written by agronomist Jamie Bultemeier

Sulfur Products, Timing, and Rate

Over the last few years many growers and crop advisors have concluded that they must supply sulfur for their crops to thrive. However, there remains confusion about which product to use, when to apply, and how much to use. The good news is that there are numerous products available that are affordable, but it is critical to pick the right product, or products, to best fit a grower’s application options.

Sulfur fertilizers deliver sulfur in three different forms, sulfate (SO₄^-), thiosulfate (S₂O₃^2-), or elemental sulfur (S₈). However, plants can only take up and utilize sulfur in the sulfate form. Applying sulfate containing fertilizers, such as ammonium sulfate, means that the sulfur is plant available as soon as the product dissolves. Fertilizers containing thiosulfate require an additional step to become plant available. The conversion of thiosulfate to sulfate is an oxidation reaction that is both chemical and biological. The portion that is converted chemically will become available relatively quickly with little influence from soil temperature. The rate of availability from the portion that is converted biologically is highly dependent on soil temperature, moisture, and pH. However, in normal growing conditions, most of the sulfur applied as thiosulfate will be available within a couple weeks. Sulfur supplied in an elemental form must go through a biological conversion to become sulfate. The rate that this process occurs is entirely weather dependent. However, it is generally estimated that about half of the elemental sulfur will become available during the growing season.

The timing of fertilizer applications in the Eastern Corn Belt is generally confined to post-harvest, pre-planting, or early in-season. Since much of the phosphorus, potassium, and liming materials are applied post-harvest, this provides an opportunity to blend a dry sulfur product with these, but which one? In most cases, sulfate forms should be avoided in the fall. While it may be convenient to blend ammonium sulfate or potassium sulfate with another dry fertilizer, these are the most prone to being lost before the next growing season. Most sulfate containing fertilizers are highly water soluble and sulfate is highly leachable from the soil profile. The exception to this is gypsum, which is calcium sulfate. While it is a sulfate form, it is not as soluble as most other forms. For the greatest efficiency of fall applied sulfur, elemental sulfur should be used. The cold, wet soil conditions over the winter months are not conducive for the biological conversion to sulfate to occur. For pre-plant and early in-season applications, sulfate and thiosulfate forms are a good option to ensure availability to the growing crop. In a dry fertilizer pre-planting application, blending ammonium sulfate with urea is a good option. At planting, a small amount can be applied as ammonium thiosulfate in a 2x2 starter, but this should be a minimal amount to avoid damaging the seed since ammonium thiosulfate has a high salt index. Ammonium thiosulfate can be applied at higher rates in a sidedress application in-season because higher salt concentration is farther from the actively growing roots. While elemental sulfur can be applied in the spring, it should be done in conjunction with a sulfate form to ensure early season availability.

Choosing the right rate of sulfur is also important to maximize the benefit of the application. A common practice is to apply a crop removal rate which is approximately 15 lb/acre in a 200 bushel corn crop or 70 bushel soybean crop. However, the total crop uptake is about double the crop removal rate. Soils do release a small amount of sulfur from organic matter decomposition, and a small amount is deposited from the atmosphere in rainfall, but in many cases, this is not enough to supply total crop uptake, even if a crop removal rate has been applied. On soils with low organic matter, well drained, or very low testing sulfur levels, application rates should be closer to a total crop uptake amount. On soils with higher organic matter, poorly drained, or medium to high soil tests, a crop removal rate should be sufficient.

Sulfur is a critical plant nutrient that should not be overlooked. Fertilizer inputs should be managed to ensure that it is provided to the crop when it is most needed and in a form that will be available to the growing crop.