Have you ever collected a “good” vs. “bad” tissue test only to find that the “bad” sample comes back with equal or possibly higher nutrient levels? When the ALGL agronomy staff reviews tissue test reports this quite common.
For a normal or average corn plant at VT, or tassel emergence, the elements on the tissue test only account for 5 to 10% of the plant’s total dry weight biomass. For an average R3 soybean plant the tissue test only reflects 6 to 10% of the total plant dry matter. So, what is the other 90-95%? Carbon, hydrogen, and oxygen mostly in the form of carbohydrates and structural components. A plant is accumulating the combination of carbon, hydrogen, and oxygen from the atmosphere and soil at a 10x faster rate than those nutrients reported on a tissue test.
Plants manufacture carbohydrates during photosynthesis to be used as energy and the building blocks of the structural components of the plants. A plant that is struggling due to compaction, lack of water, or a host of other factors so that the plant may not be able to assimilate carbon, hydrogen, oxygen at a 10X rate to the other nutrients. As a result, the plant takes up soil nutrients at a relatively greater rate than the assimilation of carbon, hydrogen, and oxygen thus causing the percentages and ppm of the soil derived nutrients to increase in the resulting tissue test data.
When the tissue test data from a “good” and “bad” plant are the same, it is showing that the plant issues are most likely not fertility related. The fact that a plant is smaller does not mean that the nutrient concentrations in the tissue tests will be lower.
A simple example. Fort Wayne, Indiana is home to Debrand Fine Chocolate. If you go into their store to buy chocolate, you can custom build a box of chocolates. If you get the 10-piece box and fill it with 2 fruit filled chocolates and 8 caramels, the fruit filled chocolates would comprise 20% of the chocolates in the box. You could also get a 5-piece box with 1 fruit filled chocolate and 4 caramels, resulting in a box containing 20% fruit filled chocolates. While both boxes are comprised of 20% chocolates containing fruit, most likely the larger box of cholates will have a bigger contribution to yield as measured by the size of your waist.
14 August 2020
A&L Great Lakes Statement on Covid-19
As the Covid-19 situation continues to evolve, we wanted to take a moment to update our customers on what we at A&L Great Lakes Labs are doing to ensure that we continue to provide the service that you have come to expect from us.
We will update these guidelines as the situation continues to evolve. We will continue to do our best to maintain the high level of service and quality that you have come to expect from ALGL. Thank you for the opportunity to earn your business.
Collecting plant tissue samples throughout the entire growing season to monitor nutrient levels has become an increasingly popular practice over the last few years. As most of the crops in our region are now well into reproductive stages, plant tissue test results need to be scrutinized carefully.
As plants transition from vegetative growth stages to reproductive stages, the nutrient content of the plant leaves will change, most noticeably nitrogen and potassium. These nutrients are mobile in plants, so as the plant starts transitioning to grain-fill, they may be translocated from the leaf to the grain resulting in low tissue test ratings that may not necessarily indicate a yield-reducing nutrient deficiency.
Another common trend in plant tissue tests is an increase in micronutrient concentrations as the plants approach physiological maturity. This is a result of carbohydrates and other carbon-based molecules being translocated from the leaf tissues to the grain effectively reducing the biomass of the leaf. The micronutrients (iron, manganese, zinc, and copper) are immobile in the plant tissue, so they remain in the leaf that has a lower mass and are now present at a higher concentration. The micronutrients may be rated as high or very high, however, this may not be an indicator of excessive fertility or potential toxicity.
While plant tissue testing can be a very effective tool for fine-tuning a fertility program, be careful not to make drastic decisions based on late-season plant tissue test results alone.
While we have not experienced a drought in 2020, there are areas of our trade area that have been abnormally dry. This article from 2012 does a great job explaining how dry weather conditions can impact soil test results.
There has been a substantial amount of information and speculation published recently regarding how the drought of 2012 may affect soil test results of samples collected during the dry period. This article is an attempt to summarize these facts.
Soil pH: Water pH readings may be 0.1 to 0.6 pH units lower than expected. This is due to a slight increase in soluble salts in the soil solution that haven’t leached into the soil profile. This condition, though, does not alter the buffer pH result so the amount of lime recommended for most samples will not be affected. An exception to this would be sandy soils where the water pH determines the lime recommendation. However, sandy soils are leached more easily so the amount of soluble salts in solution may be much lower than a heavier soil.
Potassium: Soil test levels for potassium may be lower than normal. When soils remain extremely dry for extended periods of time, the moisture that normally keeps the clay latticework open for potassium exchange retracts, capturing the available potassium from solution. This will show up as a reduction in the soil test level. Also, potassium is easily leached from crop residue following harvest. With little rainfall, this potassium reserve could remain in the tissue. One caveat of this, though, is with inadequate moisture to produce normal yields, less potassium may be removed from the soil reserve.
Phosphorus: Soil test levels for phosphorus may be slightly lower than normal. The affect of the dry soil on phosphorus levels isn’t as dramatic as potassium, but less moisture in the soil may lower the soil test readings. The same situation of reduced crop yields, though, may result in less phosphorus being removed from the soil.
Soil sampling technique: It is extremely difficult to sample dry soils. Many times the top one or two inches of the core are compressed enough that some of this material may spill out of the probe. In minimum tillage situations, this could have a dramatic affect on the soil test readings. As of the publication date of this newsletter, hurricane Isaac has deposited a substantial amount of rainfall on much of the Midwest. Soils in the lower half of Illinois, Indiana, and Ohio may have enough time to equilibrate moisture levels prior to fall sampling so that some of the drought effects will be negligible. Reduced yields, though, will still be a remnant of decreased nutrients being removed from the soil. This year is one where soil sampling should occur in order to assess the affects of this unusual growing season. Soil sampling technique: It is extremely difficult to sample dry soils. Many times the top one or two inches of the core are compressed enough that some of this material may spill out of the probe. In minimum tillage situations, this could have a dramatic affect on the soil test readings. As of the publication date of this newsletter, hurricane Isaac has deposited a substantial amount of rainfall on much of the Midwest. Soils in the lower half of Illinois, Indiana, and Ohio may have enough time to equilibrate moisture levels prior to fall sampling so that some of the drought effects will be negligible. Reduced yields, though, will still be a remnant of decreased nutrients being removed from the soil. This year is one where soil sampling should occur in order to assess the affects of this unusual growing season.
While soybean cyst nematodes have been getting most of the fanfare the past few years, corn nematodes are making their debut. While all can be damaging, some are a bit nastier than others. Their is a wide range of acceptable thresholds to treatment among the various species. The chart below gives a range of damage thresholds from several universities. While the numbers vary between sources, the pattern of the more damaging nematodes is constant. Needle and sting nematodes have the greatest potential for damage if detected.
We can analyze soil for all of these species in our N3 soil test package that provides a count for each species of nematodes with damage interpretations. For more information on sampling or sample submission contact your ALGL agronomy representative.
Tissue testing is in full swing this summer and at a rapid pace. More growers and agronomists are evaluating tissue tests to learn more about the effectiveness of their fertility programs. There are some common areas of concern arising this year. As the ALGL agronomy staff review and approve tissue test data before delivery to the customer, a trend for low sulfur, potassium, or boron is developing. The calls from growers and agronomists about these nutrients confirm that they are seeing this trend as well.
Tissue tests are very good at validating whether the crop can access the nutrients in the soil. When a tissue test comes back low for a nutrient the first question becomes, is the nutrient in the soil and the plant cannot access it, or is the nutrient deficient in the soil? Therefore, a soil sample, taken in conjunction with a plant tissue sample, is very useful.
One likely reason explaining low tissue test results for these three nutrients is a deficiency in the soil. Our annual average soil test values for these nutrients have been decreasing over the past 20 years. Less nutrient in the soil increases the probability that plants may not be able to access adequate quantities. Potassium soil test levels have been decreasing at an average rate of 0.5 ppm/year over the last 23 years. Sulfur soil test levels (measuring plant available sulfate) has declined at an average rate of 0.5 ppm/year and boron has declined on an average of 0.02 ppm/year over this same 23-year time span. This may not seem like much, but the soil test values of sulfur and boron are approximately half of what they were 20 years ago. These declines are being attributed to crop removal and/or leaching, out pacing nutrient application.
The second challenge leading to limited plant access to nutrients is weather related. Dry soil conditions can reduce the movement and uptake of all three of these nutrients in the soil, and we have seen those conditions in portions of our trade area recently. Reduced root exploration of the soil due to soil compaction is also a contributing factor in many fields. Soil compaction from traffic and tillage of wet soil the past few years have led to compaction layers restricting root growth. Heavy rains can leach both sulfur and boron, and sometimes potassium in specific situations, below the resulting shallow root zone.
Soil testing is valuable tool in ensuring you have the need foundational soil fertility for a productive crop, but tissue testing identifies if the crop can access and utilize this fertility.
At ALGL, we strive to be a company built on integrity and being easy to work with. The same goes for our shipping program. Rather than focusing on gimmicks and promotional shipping prices we provide cost effective, streamlined, fair, and easy shipping options. Your time is better spent servicing your customers than on the logistics of shipping samples.
We offer United Parcel Service (UPS) Return Shipping (RS) labels for your shipping convenience. This allows you to take advantage of our significant shipping volume discounts. By following the steps below, you can help ensure that you are getting the best prices and service from our shipping program.
1. Your Account – You must have an up-to-date, active ALGL account to use our UPS shipping program. Be sure to contact us if any updates need to be made such as contact names, street address, e-mail address, phone number etc.
2. Order Supplies– We offer 4 convenient boxes for sample shipment. Order the boxes and associated labels online or by calling the lab. You purchase the boxes and we ship them with the labels to you.
3. Pack Your Samples – Place the samples in the box so that they will not spill in shipment, tape the box shut, and affix the UPS RS label on the box. The box can be part of your usual UPS pickup, dropped off at a UPS pickup location, or you can call UPS to schedule a pickup. There may be a cost associated with a UPS on site pickup, please inquire with your local UPS representative.
4. Invoice – You are not charged for the UPS RS labels until they are scanned by UPS upon pickup. The cost of the shipment is calculated using our discount, and that amount is transferred to your invoice. The cost of the sample analysis and shipping come to you on one invoice.
UPS RS labels can be printed at any time, and there are no charges associated with the labels until they are used. This means they can be printed in advance and ready to use when you are already to ship. One challenge in printing UPS RS labels too early is that the tracking capabilities for a given label decline 12 – 16 months after creation.The date of creation can be tracked directly on the label. If you are nearing the expiration date printed on the UPS RS labels, you can request new labels by calling/emailing the lab, calling/emailing your ALGL agronomy sales representative, or ordering via our on-line store at www.algreatlakes.com.
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.
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.
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.
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.
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.