In today’s agricultural media, there is a lot of emphasis on soil health, soil biology, and soil carbon. These topics are all interrelated. Whether your goal is the improve the structure of your soil, increase the natural nutrient cycling from one crop residue to the next, or build your bank of soil carbon, the soil microbes need a steady feed source of carbon-based material to carry out these functions. However, not all materials are equal.
One of the best measurements to determine whether or not a material is easily decomposable is the carbon to nitrogen ratio (C:N). Microbes are most easily able to decompose material with a C:N around 25:1. At this level, the microbes can utilize the carbon converting most of it to carbon dioxide leaving behind soil organic matter that has a C:N of about 10:1. The microbes will continue to decompose the remaining soil organic matter, but at a slower and slower rate due to the complexity of the molecular structures that are formed.
The most common form of carbon inputs is the crop residue that remains after harvest. Soybean residue has a C:N of about 25:1, meaning it can be easily decomposed. Corn and wheat residue can have a C:N ranging from 50:1 to 100:1. While these residues are a great source of building carbon, the microbes will compete with your next growing crop for available nitrogen potentially inducing a nitrogen deficiency. Other common carbon inputs are manures. Most manures have C:N around 5:1 to 20:1 which means that there is more than adequate nitrogen for the microbes to utilize while releasing the excess for a growing crop to use. Manures with a high volume of bedding materials such as straw or wood shaving should be tested to ensure that they will not cause a nitrogen deficiency.
Most cover crops have desirable C:N for easy decomposition. However, grasses will have high carbon content than legumes, brassicas, etc. and may require adjusting a nitrogen program for the following commercial crop.
By Jamie Bultemeier - Corporate Sales Director
As the winter professional meeting and trade show season is in full swing, I am constantly thinking about the value of the time and expense versus the return from these events.
Over my 20 plus years in the industry the impact and focus of industry trade shows has changed, and conversations are different. The existing customers are still wanting to discuss current topics, however the time window of the current topics has narrowed. Today customers are not waiting the next trade show to discuss a topic. Usually they are calling, emailing, or texting within a few minutes to a few days of when the thought arose. The business growth conversations are more in depth and private today that does not lend itself to a public conversation at a trade show. The prospective customer looking for a product or service has been replaced with individuals searching for ideas and options, or information in addition to what they have discovered in an internet search. Again, that window has become narrower as the client or potential client is likely to call, email, or text long before the next trade show. The conversations at the events are becoming more personal, and philosophical, which leads to a much deeper understanding of our customers and industry partners.
Information is flowing at a much faster rate. So why incur the expense and commit the time to these activities as a business? The Covid pandemic has taught all of us that personal contact and communication is difficult at best to assign a value to. Yes, virtual events and internet searches are a great way to transfer and receive basic information quickly, but it loses the focus, concentration, and collaboration that meeting in person brings. The key aspect non-verbal communication is lost by not meeting in person. Many of the conversations had at these meetings may never take place if not facilitated by the event being attended.
The dynamics of these events has changed. We may not leave the event with as many direct sales leads as we did in the past, but we leave with an expanded and better developed network of contacts that is constantly growing and will lead to the sales growth if nurtured. Agriculture is still very much a relationship-based industry. If we recognize the changes in these events over time and modify our approach to them, the sales will come, they will just take a slightly different route to materialize.
Calcium carbonate equivalent is a measurement to determine how effective a material is at neutralizing acidity. Calcium carbonate is used as the standard to compare all liming materials to since it is the primary component of limestone. In the laboratory, the CCE of a material is measured by reacting equal amounts of each the material in question and pure laboratory-grade calcium carbonate with a set amount of hydrochloric acid. The amount of remaining acidity in each of the two solutions is then determined through a process called a titration. The CCE is then calculated by dividing the amount of acidity neutralized by the material in question by the amount neutralized by the pure calcium carbonate. This result can then be reported as a percentage.
So, what does this mean in the real world for agronomic applications? Knowing the CCE of a lime can help determine the appropriate rate to apply to our soils to raise and/or maintain the pH in a desirable range for the particular crops being grown. Most recommendations for pH correction assume that the CCE of lime is 90%. In reality quarry derived lime can often range from 75% to 110%. This means that it may take 20 to 30% more or less material to achieve the desired result. The CCE of the lime from a single quarry does not change much over time. However, the lime from different quarries can vary quite a lot. While CCE is an important property to consider when choosing a lime source, there are other factors that go into determining the overall quality of the lime and whether it is a good fit for your operation. These factors will be discussed in future articles.
ALGL has need utilizing the Mehlich 3 (M3) universal soil extractant since 1991, however most of the data sent to customer over the past 30 years has been regressed and reported as Bray P-1, ammonium acetate, hydrochloric acid, and how water boron equivalents. This has been due to most interpretive fertilizer application recommendation sets have historically been in these traditional extractions. These traditional lab methods are commonly referred to as “North Central Region” (NCR) methods. With the revision of university-based fertilizer recommendations in Indiana, Ohio, and Michigan we are seeing an increase in customers opting to receive soil test data in the raw M3 values.
Below are some suggestions to help make the transition to M3 easier.
ALGL will only change data export form upon request by the customer. If you have any questions in regard to changing to M3 data, or if we can be of assistance in the transition, please reach out to your ALGL regional agronomist.
A common question get at the lab is, “Why is the buffer pH on my soil test report blank?” When the soil pH is 6.8 or higher, the buffer pH will be blank on your ALGL soil test report, and for good reason. The reason stems from what the buffer pH value is used for.
On a ALGL soil test there are two pH columns, one titled “Soil pH” and one tilted “Buffer pH”. The soil pH is measured by combining equal parts soil and water to create a slurry. Then the pH of the slurry is measured with a pH meter. This value is used to make management decisions and indicates how the soil chemistry will be affected. For example, this is the value used when referring to soil pH restrictions on pesticides and is the pH value that is managed in soil fertility. If the soil pH is below the desired level, usually 0.2 - 0.3, the buffer pH is used to determine the amount of lime to apply to correct low soil pH soils. In high organic matter soils and soils with a CEC of 7.0 or less, other methods to determine lime application rates are used.
The highest desirable soil pH is 6.8. If a soil has a pH is 6.8 or higher there no need for a lime application to increase soil pH and therefore there is no need to determine a lime rate. Thus, no need for a buffer pH value to determine a lime rate. In GIS software data sets a value of 7.2 is often used to ensure the software calculates a “zero” lime rate without causing an error due to missing data.
The 2022 growing season could be summed up as variable. Throughout the growing season areas experienced too much rain, too little rain, and both. Leading to wide variety of water stress induced nutrient deficiencies in the crop. Despite the moisture stress the yields we good, and harvest was expedient.
Many producers pulled back on fertilizer application rates in the fall of 2021. That same trend continued into the fall of 2022 as the fertilizer prices, while variable, were showing no significant signs of relief. The question continues to be, “how long can growers go with reduced fertilizer applications?” While all fertilizer decisions are dependent on the parameters of a given situation, those growers that have focused on maintaining soil fertility levels over the past few years have had, and still have a distinct advantage.
Since nitrogen is an annual replenishment to the cropping systems, the focus of this question has been on phosphorus and potassium. It takes considerably more fertilizer to increase or decrease phosphorus soil test levels, then potassium soil test levels. Also, in most situations, crops remove less phosphorus than potassium. It may take several years of significant reductions or omission of phosphorus to start showing up in soil tests, but at some point, it will. Potassium soil test levels can decline quickly, 1 or 2 years of omitting potassium fertilizer can result in decreases in soil test levels. Potassium also impacts a plants ability to handle water stress, too much or too little.
The current market indicators are showing an increase in supply and a decrease in demand for phosphorus and potassium going into the 2023 growing season, this indicates a downward pressure on P and K prices. If this carries out, we will see 2-3 years of declined fertilizer application rates. This will be good timing for phosphorus but could be stretching potassium a bit.
The positive in all of the product challenges is that shortages were minimal. With alternates products available in most case this was a good opportunity for producers to grow in their management. This has led producer to try new products and new practices in their operations. Over the past year the agronomy staff has had a significant increase in conversations with client about closer management of nutrients, especially nitrogen. The positive to the higher prices is an overall tighter management of nutrient applications. In 1888, German philosopher Friedrich Nietzsche first stated, “Out of life's school of war—what doesn't kill me, makes me stronger.” This phrase has wide applications as the 2022 growing season pushed many producers, but it also made them better managers.
2022 also pushed us as a laboratory. We were ordering supplies upwards of 6 months in advance to keep the lab operational. The entire year was plagued with supply price increases, supply shortages, shipping delays and labor shortages. The spring soil sampling season volumes were higher than normal with many samples not completed due to the wet fall of 2021, which prevented some soil samples from being collected. This along with strong fertilizer prices led to increased soil sample volumes in the spring of 2022. Strong grain prices supported stronger than normal plant tissue testing volumes during the summer. The fall soil sampling brought a compressed sampling season. Southern Indiana through Tennessee was 3-4 weeks behind in crop development while Michigan and Wisconsin were 2-3 weeks earlier than normal. Usually, samples start coming in from the southern parts of our sales territory in mid-September and there is a 5-7 week delay until northern Michigan hits full harvest. This year the entire service territory started in early October, compressing that start window to about 2-3 weeks. Without any major weather systems hitting the region, sample volumes were continuously strong from early October till early December.
While 2022 proved challenging for all aspects of crop fertility in production agriculture, the dedication of those we work with made it successful. Thank you to our suppliers for doing what they could to always keep us operational. Thank you to the lab staff for their creativity, planning and amazing work ethic to do whatever it took to keep the samples moving for our customers. Finally thank you to our customer for putting your confidence in us, for the long/constant hours to keep the samples flowing into the lab, and for the partnership to work through any challenges that arose. While 2022 was difficult, it was also rewarding to see what we all accomplished working together.
Through the last quarter of 2022, prices of nitrogen, phosphorus and potassium fertilizers continue to diverge. As the price of these fertilizers increased at different rates, and for different reasons starting back in early 2020, the prices continue to respond independently. As phosphorus prices began climbing slowly in 2020, potassium followed later in the winter of 2020/2021.
In agricultural production, the adage “hindsight is 20/20” is all too true in respect to fertilizer purchase decisions the last two years. For example, as prices climbed in 2021, those producers that purchased the elevated prices in the summer of for application in the fall of 2021 made a wise decision as the prices continued to climb through harvest and the following growing season. Delayed fertilizer purchases, and application, has led to increased input costs during the 2021 and 2022 growing seasons. Looking back hesitation has not been a profitable approach to fertilizer purchases, which is often the case in any strong fertilizer price rally. Conversely, those that hesitate may benefit as prices decline.
So, what does the future hold? Foreseeing the future is an educated guess at best. Fertilizer prices are beginning to soften due to reduced demand backed with ample production. The exact opposite market forces that started the climb in prices in the fall of 2020.
How far and how soon fertilizer prices decrease is not yet known, but the signs in the market are showing both phosphorus and potash to be trading sideways to down. The downward pressure is focused on potash, yet phosphorus is responding more. The outside market pressures driving the nitrogen market much more volatile currently. It appears for the near future that nitrogen will remain choppy at best. Of the three main nutrients, nitrogen is impacted the most by the outside markets with continued steady to growing demand in the coming months.
Sometimes we as agronomic professionals become a bit anesthetized to the amazing and complex natural systems that we work with every day. The myriad of intricate chemical, physical, and biological interactions that make our soils function to support plant growth, clean our water, recycle nutrients, and overall sustain life on this precious planet are awe inspiring. And the plant, that "simple" form of life that has existed in different forms over millions of years, and that we as professionals have harnessed to feed the world, is a delicate and complex machine, capable of utilizing light from the sun and elements in our atmosphere and the soil to feed almost every other form of life on the planet.
While most of the time these lowly systems work without much pomp or fanfare, every fall they put on a show for all of us to enjoy.
The tourism industry is gearing up for 6-8 weeks of high traffic, full restaurants and hotels and increased incomes as travelers head to their favorite locations to view the fall colors. As days become shorter, temperatures become cooler the chemistry of the changing tree leaves begin to reveal the spectacular fall scenery. The National Park Service fall foliage map published September 21, 2020 show areas across northern MN, WI and MI at or near peak fall color and the prime viewing will move southward over the coming weeks.
Arborists have discovered some of the key environmental conditions needed to bring out the best colors are adequate summer rainfall with good growing conditions followed by a dry fall with cool nights, warm daytime temperatures and good sunlight.
Chlorophyll (green), carotenoids (orange), flavonoids (yellow), Anthocyanins (red/purple) and tannins (brown) are present in the leaves during the summer growing season but chlorophyll dominates the light spectrum absorbing reds, yellows and blues while reflecting the green color that we see. Chlorophyll production slows during the early fall and anthocyanin production increases which allows the vibrant colors to come into view. In late fall tannin content increases giving many of the leaves a dark brown color and the bright reds and yellows slowly disappear.
These chemical processes involve many of the same components that we see in crop production, ornamentals and foods. Anthocyanin is produced and stored in corn leaves early in the season when nights are cool and plant growth is slow and it reveals the same purple colors in corn leaves that are apparent in the trees during the fall. Carotenoids give carrots their orange color and the yellow flavonoids give egg yolks their bright color. Many combinations and variations of these same chemical components make up the bright flowers and unusual leaf colors that we see in ornamental plants. Tannins that give leaves their brown colors are responsible for the signature flavor of a green persimmon and they give tea leaves a variety of flavors.
The staff at A&L Great Lakes Laboratories would like to wish you a safe a prosperous harvest season and we hope you take some time to enjoy the beautiful fall colors.
The dry soil sampling conditions this fall has led to a variety of questions focusing on when clients should stop pulling soil samples. The soils need to be very dry for an extended period of time before the impacts to soil sample data become noticeable. The first indication is when you are unable to collect a soil sample to the proper depth, especially with a probe sampler. Often an auger sampler will do a better job in dry soils. Incorrect sampling can have a bigger impact on soil test results than the dry soil itself.
A good way to make a determination on when to stop soil sampling based on drought conditions is to use the USDA drought monitor. Drought maps can be found at https://droughtmonitor.unl.edu/. The actual impact of drought on soil sample data will vary based on cropping system, region of the county, soils, etc. The following is a simplistic reference to help determine when drought conditions may bias soil test results. D0 drought should have little to no impact on soil test results providing a proper soil sample can be collected. However, D0 drought can begin to make sampling some fields with a probe challenging. Late D1 and into D2 drought is when you may consider stop sampling. This is about the point in the drought continuum when sampling and drought bias on soil test results can become noticeable. D3 is a time sampling should cease. If you have any questions reach out to your ALGL Regional Agronomist.
Collecting plant tissue samples throughout the entire growing season to monitor nutrient levels has become a common practice over the last few years. As most of the crops in our region are now well into later grain-fill stages, plant tissue test results need to be evaluated with a cautious eye.
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 test nutrient levels 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.