Often the number of turf soil samples and related phone calls to the lab increase in late August into September. Many of them with similar concerns as the turf growth slows and, in many cases, turns brown. Most are looking for what fertilizer or product to spray or apply to correct the issue. This is a simple fix, repeated liberal applications of dihydrogen monoxide… water. Applying more fertilizer is not always the answer.
We can see the same in crop production fields when the weather turns dry leading to reduced nutrient availability manifesting as visual deficiency symptomology, and possibly lower nutrient levels in tissue tests. While often the goal of crop fertility is seen as maximizing yields, additionally the goal of soil fertility is to reduce the risk of negative impacts to plant growth in challenging growing environments.
In either situation, being prepared ahead of time with adequate N for a strong and healthy plants, proper phosphorus levels to promote root development and sufficient potassium to aid in water management within the plant. Good fertility management aims to reduce the risk from uncontrollable factors, like droughty weather patterns, that can negatively impact crop nutrition. Keep in mind that controllable factors, such as soil compaction and poor drainage, can also manifest themselves as a nutrient deficiency.
When a plant is struggling, the immediate application of fertilizer is often not the answer. Could it be an underlying related agronomic issue? Could it be bad luck presenting you with an uncontrollable factor? Can the risk of a negative yield impact from this uncontrollable factor be mitigated in the future? The first step is using soil testing to ensure the foundational soil fertility in place in advance of the challenges of the growing season, and then use tissue test to verify at that the plants can access the soil fertility you have provided.
Beginning August 1, 2021, the updated Tri-State Fertilizer Recommendations will be available from ALGL. This includes both recommendations requested on soil submittal forms and through SoilTrak.
Listed below are the details for the new recommendations. If you have any questions, feel free to contact your ALGL agronomy representative.
While fertilizer prices continue to increase, the rate of increase is slowing. It appears that the fertilizer prices are starting to stabilize. The price spike was largely due to supply shortages, supply chain disruptions, and higher producer demand following increasing commodity prices leading to more favorable farm income. While the prices are stabilizing at a higher level, many growers are looking to retain some of the increased revenues from improved grain prices. This is driving producers to evaluate fertilizer cost reduction strategies.
The second, and maybe bigger issue is the fact that the supply side of the equation has not changed and maybe growing tighter. While making plans to reduce fertilizer cost, producers also need to be making contingency plans if they cannot source enough fertilizer to meet their needs.
The strategies used in this situation will be very similar to those used when commodity prices are low but having a “Plan B” in the event that fertilizer is limited will be a new concept to look at. The first goal is to ensure that yield is not put at risk if possible, and the strategy will vary by nutrient.
All forms of nitrogen have about doubled in price in the last year. Concerns over anhydrous ammonium supplies have been minor, however dramatic increases in urea and UAN demand have greatly reduced the stock of these products in the field. The positive is that the high prices are delaying inventory purchasing to allow the supply chain inventory to refill. Flexibility in nitrogen source maybe key in the event one of the main materials supply declines.
Look for greater nitrogen use efficiency:
One of the greatest challenges in building phosphorus soil test levels is that it takes several pounds of phosphorus to raise a soil test 1 ppm, this is also an advantage in that it takes quite bit of crop removal to decline soil test levels. First separate your maintenance (crop removal) fertilizer rate from your build rates. The build rates can be reduced or eliminated if needed. Maybe prioritize the build on those fields with the lowest soil test values to make sure the build process continues.
If you’re not taking advantage of a precision ag based fertility program, know is the time to start. Putting the fertilizer where it is needed will pay in these challenging times. If you are in a program, take it the next level and add yield monitor crop removal. Replace only what the crop removes. In the events of very tight supply/cost and with good phosphorus levels, this technology could be used to apply less than crop removal on a percentage basis for a growing season or two with less negative impact than other nutrients.
Potassium soil test levels can change quickly, and it is not recommended to apply less then crop removal if the soil test levels are at or below targeted levels. Like phosphorus, build portions of fertilizer recommendations could be omitted. This again is a key advantage of a precision ag fertility programs with more frequent sampling cycle to keep current on soil test potassium levels.
Some research suggests that annual application of potassium fertilizers can increase yield. This reduces the volume needed to complete the fertility plan and reduces the price risk of buying fertilizer at the highest price for an extended crop rotation. If you traditionally apply your fertilizer in the fall, you many look into the logistics of spreading some or all of your potash in the spring in the event fall supplies are short.
If you have any questions on how various management decisions may impact soil and plant fertility, be sure to reach out to your ALGL agronomist sales representative.
2021 has been another unique growing season to date. Some areas receiving more rain than needed, while other less than needed. This had led to either a highly variable crop or an outstanding crop, either way you can benefit from incorporating yield map crop removal into your fertility recommendations.
Soil fertility recommendations have two key parts that are added together to arrive at a final nutrient application rate. Part one is crop removal. How much fertilizer do I need to apply to account for or replace the nutrients removed by harvesting a crop? The second part is how much fertilizer above crop removal do I need to apply to increase soil test levels from where they are to a target level over a given period of time. Most recommendation sets are built to move from the current soil test level to a target in 4 years, that time frame could also be extended to reduce application rates. Likewise, how much less than crop removal do I apply to reduce soil test levels to target levels over a given period of time.
Traditional soil fertility recommendations take the approach of predicting or forecasting crop yields for the coming year or two. That may be as accurate as forecasting the weather. When it comes to determining the amount of fertilizer needed to replace the nutrients removed by harvesting a crop, yield records are often more accurate than yield projections.
Rather than forecasting yield using a 10-year average or a yield goal for future yield, and applying fertilizer in advance, shift your mindset to replace the nutrients that past crops have removed. For example, you may have forecasted a 200 bu/ac corn crop for 2021 sometime before planting the 2021 crop, spread fertilizer, and now due a good growing season the yields may look more like 220-225 bu/ac. So effectively this leads to a 10-12% under application of fertilizer in 2021 by incorrect forecasting. The use of yield monitor data, storage structure estimates, and scale tickets of past yield values are significantly more accurate than forecasting future yields.
When forecasting yields these overages are often not accounted for in the subsequent years. In years when yield is higher than expected we can actually short for the following crops. While routine soil sampling can catch these variances, there maybe an economic or agronomic impact until the next sampling cycle, or longer.
The main questions. So, what’s in it for the producer? And what’s in for the fertilizer retailer? The producer’s key to future stability will be through better management. This process allows a producer to follow a low yielding year with an input reduction and hopefully be able to effectively maintain strong soil fertility after an exceptional yield year. The ag retailer that takes the effort to work through this transition building a stronger partnership with the producer in these tighter times will differentiate themselves in the marketplace. Better management is often the key to better profitability for both parties. Contact your ALGL agronomy representative with any questions you may have on this topic.
Tissue samples are submitted to the lab with the sample ID ‘s of “good” and “bad”, and often the tissue test data results are very similar. Sometimes the “bad” sample will have higher nutrient concentrations than the “good” sample.
Tissue test data is a concentration of a given nutrient within the plant biomass. The concentration is the relative amount of a given nutrient within a defined volume of plant biomass.
Impact of nutrient uptake and plant size on tissue test results.
If nutrient availability in the soil is not limiting, there is no reason to expect the tissue test data between a “good” and “bad” sample to be significantly different. if a plant is limited by physical or environmental factors leading to reduced plant growth, the biomass volume of the impacted plant will be less. Equally decreased nutrient uptake by the impacted plant will lead to a less total nutrient in the plant tissue tested. Often the decrease in plant biomass is correlated to the relative decrease in nutrient uptake. This leads to a very similar sample nutrient concentration. If the plant biomass is severely impacted while nutrient uptake continues the impacted plant could result in elevated nutrient levels. Observation notes and pictures taken at the time of sampling can be very valuable in interpreting plant tissue data.
Getting a tissue test report back form the lab showing that both the “good” sample and “bad” sample have adequate nutrient concentrations to support plant growth does not mean the tissue test did not tell you anything. It means the issue affecting the growth of the “bad” sample is most likely not nutrient related. Contact your ALG agronomy representative for support using plant tissue data in diagnosis situations.
Over the last few weeks, we have received many soil samples for nitrate analysis to help determine what rate of nitrogen to sidedress in corn. Several of the samples have generated questions for our agronomy staff regarding unusually high nitrate results. Upon further investigation we have found that many of these fields with high nitrate levels have one thing in common, they had manure applied since the previous crop was harvested. This is the exact scenario that the pre-sidedress soil nitrate test (PSNT) was developed to assess. Each university extension program in the Great Lakes region have developed interpretations for determining what rate of nitrogen to apply based on the soil nitrate level, and they all basically agree that if it is above 25 ppm, no additional nitrogen is needed. This year it has not been unusual to see 50 to 100 ppm.
Where is all this nitrogen coming from? Simply stated, we can thank the fall, winter, and spring weather. Last fall was dry, which allowed for timely manure applications. The winter was relatively dry and cold. This kept the microbial activity to minimum reducing the chance for nitrification and mineralization to occur that could lead to nitrogen losses. The early spring was cold through most of May, again minimizing nitrogen losses. Then early June got hot with some rain, and it kicked the microbes into high gear converting ammonium and organic nitrogen sources into nitrate.
So, what do we do with these high numbers? Most growers who use manure as part of their nitrogen program know that even an aggressive fall manure application will likely run short on nitrogen and generally require a supplemental source to get through the whole season. Even though the university interpretations say there is more than enough, you need to consider each situation on its own. Irrigated ground with a 300+ bushel potential is certainly going to require much more nitrogen than dry ground with 150 bushel potential. Is there an option for late season applications, such as fertigation or a high clearance spreader? If you are in a situation where your current soil test nitrate levels do not justify a sidedress application, your best bet is to monitor the crop. At tasseling, a corn crop should have taken up 60 to 70% of the nitrogen it needs for the season. Collecting a plant tissue sample at this time can potentially identify a nitrogen deficiency before any visual symptoms appear.
If you have any questions or want to discuss your own situation, contact your ALGL representative.
The ALGL agronomy staff is regularly quizzed about the value of tissue testing. Often the focus is to verify a visual nutrient deficiency, then determine what foliar fertilizer to spray. While this is a valid application of the management tool, there are greater benefits to be had by using the information to avoid the issue in the future.
Think of the tissue test as a report card for your overall crop and soil fertility management plan. With a tissue test collected just before and during key physiological growth periods of the crop can help find week points in the overall soil/crop fertility plan. If a deficiency is found a quick rescue maybe the applications of a soil or foliar fertilizer, but how do you avoid the same situation occurring in the future? The greatest value in tissue testing is not only identifying a fertility issue and correcting it now and adjusting in your soil/crop fertility management plan to avoid the recurrence of the situation, while using routine soil and tissue testing to verify the correction of the issue.
A simple example. You notice areas of your soybean field showing interveinal yellowing of younger leaves. The tissue test confirms that the plant is deficient in manganese. The quick response is a foliar application of manganese to correct the issue. A soil test collected at the same time as the tissue test shows low levels of manganese in the soil, so the cause of the plant deficiency was due to the soils inability to supply the nutrient. The foliar application addresses the symptoms, but not the cause. Without proactively addressing the soil fertility issue along and/or planned foliar applications, the issue most likely will reoccur in the future. The knowledge from the tissue and soil test can help drive changes in the crop/soil fertility plan to avoid the issue in future years in conjunction using tissue and soil tests in future crop season to confirm the change in the plan continues to correct the issue.
The goal of any good nitrogen (N) management program is to maximize yield and minimize inputs. For corn growers that utilize manure or other organic forms of N, using the Presidedress Soil Nitrate Test (PSNT) can be a good tool for fine tuning N needs of the crop prior to sidedressing with N.
The PSNT is a way to measure the amount of N, in the form of nitrate, which is supplied by organic materials in the soil. The procedure was developed to measure the amount of N that is naturally released, or mineralized, from the decomposition of organic materials in the soil. This test is applicable in fields where manure has been applied, following legume forage crops, or following cover crops.
Sampling for the PSNT is different than routine soil sampling. Samples are collected approximately 1 week prior to a planned sidedress application, generally when corn is 6 to 12 inches tall (V4 to V6). Samples are taken to a depth of 12 inches. Take 10 to 15 cores to represent one sample area. Sample area should be determined based upon factors that influence mineralization rates such as drainage class, slope, cropping history, and rate of manure applications. A single sample should represent no more that 15 to 20 acres. The samples should be shipped immediately to the lab for analysis. In situations when shipping is delayed, refrigerate or freeze samples until they can be shipped or delivered to the lab. Samples should be shipped early in the week to avoid weekend delays.
We understand the importance of PSNT in your nitrogen management programs, so we provide one day turnaround time for soil nitrate samples.
Most states have developed interpretive guidelines for the PSNT. While most states have very similar interpretations, we recommend looking into other states in the region to help guide you to make the best management decision for your operation.
As mentioned previously, the PSNT is intended to measure the N from organic matter decomposition, so if a high rate of N was applied pre-planting, the interpretation of the results may not be accurate. For additional information on PSNT from A&L Great Lakes Laboratories, please see our Fact Sheet.
Indiana: Purdue Extension
Ohio: Ohio State University Extension
Michigan: Michigan State University Extension
Illinois: University of Illinois Extension
Wisconsin: University of Wisconsin Extension
A&L Great Lakes Labs Fact Sheet: In-season Soil Nitrate Testing for Corn
It is no surprise to those farming or in ag retail that fertilizer prices have been going up. In the past year nitrogen prices have increased an average of 36%. Urea is up 31%, anhydrous ammonia up 39%, and 28% UAN is up 45%. When looking at the cost of an individual pound of nitrogen from these products the gap grows. In March of 2020, the cost was $0.30/pound of nitrogen for anhydrous ammonia and $0.42/pound of nitrogen for urea and 28% UAN. Fast forward to March 2021, we are at $0.42/pound of nitrogen with anhydrous ammonia, $0.55/pound of nitrogen with 28% urea, and $0.61/pound of nitrogen with 28% UAN.
So, are fertilizer manufactures trying to get their part of the grain rally? Maybe not. Fertilizer price increases started back last fall with MAP and DAP prices beginning to rise in September of 2020. Potash began its climb in December of 2020. Nitrogen hung back and started its big climb in February 2021, according to Progress Farmer DTN’s data. Looking back the rally in grain prices started gaining noticeable momentum in September/October of 2020. This seems to correlate rather closely with rally in grain prices on the surface. While this seems more than coincidental, fertilizer prices do not move that quickly, there is couple month lead time on fertilizer price changes.
Ag retailers began seeing tightness in supply and were forecasting price volatility of fertilizer in the middle of 2020. By late-summer 2020 retailers were talking to customers about prepaying fertilizer, especially nitrogen, to offset potential fertilizer price increases before the grain rally began.
The strong yields, government payments, and the grain commodity price rally led to strong farm incomes in the fall of 2020. This additional income then led to strong and swift increase fall fertilizer sales. Favorable fall weather for the first time in several years also allowed ample time for fertilizer to be spread and fall tillage to be completed. This complex led to a rapid realization of pent-up demand for fertilizer. It was a race to keep fertilizer in the warehouses to meet this demand. At the end of harvest many fertilizer warehouse inventories were low to exhausted. The fertilizer infrastructure was impacted by simple supply chain disruptions like other markets, and reduced product forecasts based on downward sales projections from the past few years, started to tighten supply and initiate the price increase in the summer of 2020. The good yield and commodity prices added the fuel to the fire. The unexpected demand for fertilizer created by farmer buying, combined with strong worldwide demand in a tight supply market, is driving the fertilizer prices higher.
So, what can be done at the farm gate to manage this? Yes, the grain markets are strong, and the extra income can cover this extra cost. But do you have grain to sell at these higher prices, or did you sell straight out of the field last fall or locked in prices too early in the rally? Would you like to hold on to some of the extra profit in 2021 to shore up your cash position? It is in times like these that solid crop fertility management can help achieve your financial goals for you faming business. Your ALGL regional agronomist is ready to help you achieve your business goals, and your customers business goals, by getting as much as you can out of every dollar spent on crop nutrition.
The nutrient characteristics of a manure is dependent the species of animal, the diet of the animals, and how the manure is handled. In recent years crop managers have been advancing the use of liquid swine manure from waste product to nutrient source. To efficiently utilize the nutritional benefit of liquid swine manure takes a bit of management.
The nutrient content of liquid swine manure is less concentrated than other manures which adds additional handling challenges handling large application volumes per acre. Effective manure management of liquid swine manure starts well before the day of application. The greatest variable in liquid swine manure is moisture content. The moisture content of liquid swine manure is mostly dependent on external water sources. Excess drinking water loss to barn manure pits, wash water from the barn, along with rainwater additions to open exterior pits increases water content of the manure resulting in a dilution of nutrient content. Reduction of external water making its way into storage pits and lagoons can help reduce dilution. In pits and lagoons, the solids settle to the bottom of the pit or lagoon creating a stratification of manure moisture content with depth. As much agitation as can be safely achieved at application time can help reduce variability in the nutrient content of the applied manure.
Most of the nitrogen in liquid swine manure is in an ammonium form rather in organic forms. The amount of organic N is directly related to the solids content in the manure, which is usually low. The solid fraction separated from whole manure or cleaned from the bottom of a lagoon/pit after settling, can have more organic nitrogen than ammonium. Any organic forms of nitrogen in manures need to be mineralized into inorganic ammonium before becoming plant available, this additional step in making organic nutrient forms plant available further slows the release to plant and help reduce potential losses. Especially in cold soils which are not conducive to microbial activity needed to break down the complex organic molecules. The ammonium form of nitrogen is held by the soil cation exchange capacity (CEC) and is directly available to plants for use and to soil microbes for conversion to nitrate. Ammonium is subject conversion to nitrate and possible loss in warm (over 50⁰F) and moist soils. For fall and early spring liquid swine manure applications, ammonium nitrogen stabilizers can be added to reduce/delay the conversion of ammonium to nitrate.
If liquid swine manure is applied in the fall before the soil temperature falls below 50⁰F, or if a period of warm temperatures occurs in the spring prior to planting allowing soils to warm up above 50⁰F for period of several days, non-stabilized ammonium nitrogen can rapidly convert to nitrate and become subject to loss. If these conditions occur when the manure was applied as a planned nitrogen source for corn, it is highly recommended to perform a presidedress soil nitrate test (PSNT) to evaluate soil nitrogen levels and the need for supplemental nitrogen. Given that most of the nitrogen in liquid swine manure is plant available at time of application makes liquid swine manure a good nutrient fit for side-dressing corn, and top-dressing winter wheat.
Most of the phosphorus in liquid swine manure is in an organic form so the concentration of phosphorus is directly related to the solid content of the manure. Liquid swine manure phosphorus content increases with increasing solids content. Potassium is water soluble in the liquid fraction and the concentration remains relatively constant regardless of manure solids content.
Ammonium nitrogen, soluble phosphates, and potassium contained in liquid swine manure are highly water soluble and contained within the liquid fraction of the manure. Off-site movement of liquid swine manure nutrients could occur rapidly if surface applied to the soil without incorporation, applied to areas of the field prone to concentrated surface flow, close to open drains/ditches, shortly before heavy rains, and to frozen or snow-covered fields. Incorporation of liquid swine manure greatly increases the retention of nutrients and reduces odor.
Nutrients targeted in feed rations can become elevated in the manure. High concentrations of zinc used in nursery feeding often leads to elevated zinc levels in manure. Repeated application of high zinc manures on the same field can lead to elevated zinc soil test levels. Some zinc is beneficial to crop growth, especially corn, however elevated zinc levels can lead to reduced plant growth.
Chastain, J.P., J. J. Cambarato, J. E. Albrecht, and J. Adams. (1997). “Swine Manure Production and Nutrient Content. Swine Training Manual.” (pp 3-1:3-15). South Carolina Cooperative Extension.
Lorimor, J., W. Powers, A. Sutton. (2004). “Manure Management System Series. MWPS-18, Section 1 - Manure Characteristics.” 2nd ed. Midwest Plan Service, Iowa State University.