Tag: Nitrogen

Biological Products: To Use or Not To Use (and how to systematically answer this question)

Nicole Fiorellino, Extension Agronomist | nfiorell@umd.edu
University of Maryland, College Park

Have you thought about how you might incorporate newly-available biological products into your operation? Maybe you are interested, but skeptical about the return on investment? I will briefly define “biologicals” then provide my thoughts on how to navigate the old adage, “to use or not to use.” I operationally define biological products as commercially-available amendments that are adding a living organism to your growing system, either to the soil or directly to the plant. Generally, these products are meant to replace a fertilizer application by unlocking nutrients stored in the soil or amplifying natural processes that harness nutrients, namely nitrogen (N), from the atmosphere. While a variety of products from different brands can be broadly categorized as biologicals, it is important to take the time to understand the specific “mode of action” of individual biological products and compare that to your field conditions as a first step towards deciding if you will use a product.

Most biological N products aim to increase the mineralization of organic N stored in your soil to inorganic forms that are plant available. The mineralization step of the N cycle is mediated by microorganisms that spend energy to digest organic N and transform it to inorganic, plant-available N. When there is ample inorganic N present in the soil, like after a fertilizer application, for example, the microorganisms are “signaled” that ample N is present and they conserve energy by slowing down, or even stopping, mineralizing organic N. So biological products aim to “block” the signal to microorganisms that instructs them to cut off mineralization and they signal microorganisms to increase the organic N that is mineralized; hence adding more N to the soil with additional fertilizer application.

The increased availability of the soil storage of organic N or the provision of N to plants without fertilizer is accomplished through the introduction of novel N-fixing bacteria that allow a cereal crop, like corn, to fix N like a legume; by providing a stimulant to native soil bacteria to kick-start mineralization; or by infecting the corn plant with an N-fixing bacteria that fixes N from the atmosphere with no additional available N present in the soil – each of these examples represents the mode of action of a different biological product. While it seems like these products have the potential to supply nearly unlimited amounts of N to your crops, they should be viewed as fertilizer replacements, not necessarily as bonus N on top of your current fertility plan. Moreover, despite some marketing claims that yield benefits would be observed across all acres of a farm, a farmer might be more likely to observe a yield response where fertility is low, maybe on marginal acres where fertilizer applications or field operations are delayed due to logistics and timing. Finally, beyond the cost per acre of the product itself, you may want to consider the ease of use of the product and the cost in time associated with product use, including restrictions on tank mixing, application timing, and extra trips across the field.

Once your head is spinning from those considerations and you think you may want to try a new product, your next step may be to see out local research data on a product’s efficacy or maybe even check with your neighbor to learn about their experience with the product. The specific nature of the individual biological products and their interaction with soil nutrient concentration means that University data or even data from your neighbor may not represent the results you might expect on your farm. Unlike the universally-expected yield response with increased fertilizer application across the spectrum of soil and environmental conditions, the potential yield response to the use of biological products varies greatly with location, soil type, and weather conditions – meaning in the same location across multiple years, there may be a different response to the use of these products.

We recommend performing trials on your farm to aid your decision to use biological products. A first step to determine a yield response will be to understand how efficiently you are using N fertilizer on your field. This can be accomplished with a simple field-length strip plot protocol using multiple N fertilizer rates and up to two biological products of your choice. The Agronomy Program at University of Maryland has launched an On-Farm Trials program, with funding support from the Maryland Grain Producers Utilization Board. We encourage farmers to sign up to participate in the trials, one protocol is a biological product comparison. As we enter our second field season in 2024, more information for how to sign up for the trials and brief results summary from 2023 can be found at https://bit.ly/UMDOnFarmTrials or you can email Dr. Nicole Fiorellino at nfiorell@umd.edu or Mr. Gene Hahn at ghahn@umd.edu for more information. We offer a payment to offset potential yield loss and to compensate you for your time spent working with our team to execute the trials. If you have not planted corn yet, there is still time to sign up! Check back to the November research summary issue of Agronomy News for 2024 Field Trials results.

Farmers May Fertilize Small Grains With Commercial Fertilizer Beginning February 15

Reposted from the Maryland Department of Agriculture

The Maryland Department of Agriculture today announced that farmers who planted small grains for harvest last fall may “top dress” these crops with commercial fertilizer in accordance with their nutrient management plans, beginning February 15, provided that crop and field conditions remain favorable.

University of Maryland researchers have determined that crop growth stages vary across the state. The Lower Eastern Shore of Maryland and Southern Maryland appear to have met the appropriate time to top-dress. However, the Maryland Department of Agriculture has given approval to all Maryland farmers to begin applying fertilizer to small grains, as long as crops have reached the “green-up” stage before applying fertilizer. The University recommends split applications of spring nitrogen with the first application occurring at “green-up” and the second application when the crops begin to joint. Check individual field conditions and avoid running heavy equipment across saturated soils.

The determination follows Maryland’s nutrient management regulations. As a reminder, manure may not be applied to fields until March 1.

For additional information on Maryland’s nutrient application requirements, contact the MDA’s Nutrient Management Program at 410-841-5959.

For a directory of University of Maryland Nutrient Management Planners, visit: https://extension.umd.edu/resource/ume-nutrient-management-advisors/.

First-Ever Mid-Atlantic 4R Symposium

Mid-Atlantic 4R Alliance press release

As regional affiliates of the Mid-Atlantic 4R Nutrient Stewardship Association, the Delaware Maryland 4R Alliance and Pennsylvania 4R Alliance will be co-hosting the first-ever 4R Symposium. Join our teams for free on August 31st at Cecil College in North East, MD for 4R farming presentations.

Invited Presenters and Topics:

  • Dr. Tom Bruulsema with Plant Nutrition Canada – Nitrogen Use Efficiency in Responsible Plant Nutrition
  • Eric Rosenbaum with Rosetree Consulting – Splitting your Nitrogen Fertilizer – what the yield results tell us
  • Peyton Harper with The Fertilizer Institute – 4R Program Offerings and Resources
  • Dr. Nicole Fiorellino with the University of Maryland – On-Farm Trials
  • Dr. Leanna Nigon with The Fertilizer Institute – Realizing Economic and Environmental Outcomes with the 4Rs

Save your seat and reserve a free lunch by RSVPing online here. Nutrient Management and Certified Crop Adviser credits will be available for Delaware, Maryland, and Pennsylvania.

The Mid-Atlantic 4R Nutrient Stewardship Association works to provide education to farmers on the economic and environmental benefits of implementing 4R nutrient stewardship practices while communicating to non-agricultural audiences by documenting on farm 4R successes and environmental outcomes.

If you are interested in sponsoring our event, please contact our team at thompsonagconsulting@gmail.com for a sponsorship packet to see all that we have to offer.

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The Delaware Maryland 4R Alliance is a collaboration between agribusinesses, farmers, government agencies, conservation groups, and scientists working to ensure that every nutrient application on Delaware and Maryland farms is consistent with the 4Rs. Learn more about DEMD 4R’s work here.

The Pennsylvania 4R Alliance collectively works with farmers to deliver science-based systems that improve crop productivity through increased nutrient use efficiency and reduce losses of nutrients to the environment. Learn more about PA 4R’s work here.

Seeking On-Farm Research Partners

The Maryland Grain Producers encourages you to sign-up for one of the three new on-farm research trials for the 2023 growing season! Maryland grain check-off dollars are funding technical assistance through the University of Maryland and compensation to you, for this year’s on-farm research. Conducting this applied research on farms will lead to meaningful agronomic production data across the state at the field scale.

The three different trials are listed below. Full protocols can be found online at https://go.umd.edu/3n39mzm.

  • Nitrogen Rate – the study is evaluating corn yield response to a range of nitrogen application rates.
  • Biological Product Evaluation – the study is going to determine the impact of biological fertilizer enhancement products on corn yield.
  • Potassium Rate – the study will evaluate corn yield response to potassium fertilizer to determine the agronomic critical level and adjust land-grant fertilizer recommendations.

The University of Maryland has been funded by check-off dollars to benefit the future of Maryland grain production, by doing on-farm research. Dr. Nicole Fiorellino and Gene Hahn, the On-Farms Trials Coordinator, will be working directly with you to provide hands-on assistance throughout the entirety of the trial. Compensation is available to participating growers who complete the protocols on their farms.

Findings will be aggregated with no identifying information or location and shared for other farmers to see and learn more. Contact Dr. Fiorellino directly at 443-446-4275 or at nfiorello@umd.edu to enroll today!

To learn more about what check-off dollars are funding, visit our website at marylandgrain.org/checkoff-grant/.

Earn a gift card by telling us about your thoughts on nitrogen management in the Chesapeake Bay watershed

What are your thoughts on nitrogen management in the Chesapeake Bay watershed? What can we do to reduce nitrogen pollution in the Bay while meeting the demands for nutritious food and economic development? Your thoughts are very important for us to identify barriers and opportunities for improving the Bay’s health! Thanks to our farmers, we have made progress in reducing nitrogen pollution reaching the Bay in the past few decades, but there is still more work to do.

If you live/work in the Chesapeake Bay Watershed and are over 18 years old, we would like to invite you to take a quick online survey (password: cafe2021) to share your thoughts. Our research team at the University of Maryland Center for Environmental Science developed this project to help understand and increase the region’s capacity to efficiently and profitably manage nitrogen across the food system, from crop and animal production, to distribution, to consumer waste treatment! Reducing nutrient loss depends on all parts of the food system, and participation of all different stakeholders like you!

This survey will take about 20 minutes. We will email the first 100 participants a $20 e-gift card. This survey is part of an NSF-funded project and it is approved by the University of Maryland Institutional Review Board ([1864028-3]. Sustainable nitrogen management across spatial and system scales). Please find more details about the project in the document attached. Any questions, please let us know. You can contact us via this email cafesurveys@umces.edu. Thank you in advance for your contribution to the research project and the Bay’s health!

Best regards,
The CAFE Team
cafesurveys@umces.edu
University of Maryland Center for Environmental Science

Final Year of Split Nitrogen Cost-Share

Queenstown, Maryland (January 26, 2023) – Cost-share is available to farmers interested in adding an additional split to their nitrogen application on their 2023 corn crop. The Mid-Atlantic 4R Nutrient Stewardship Association and their agribusiness partners will work directly with producers in the Chesapeake Bay Watershed for the third and final year of this grant opportunity. Farmers who apply an additional split of nitrogen, and leave a control strip with the same total poundage will be eligible for a $15 an acre incentive payment.

Farmers are eligible to enroll 40 acres or 400 acres, as long as a control strip is available in each field. The 4R Alliance requires past crop and yield data as well as 2023 corn yield checks to analyze and compare results. Data collected over the three-year grant will be compiled for a published case study.

In 2021, five Maryland farms participated and had an average yield increase of 19.2 bushels per acre where they use an additional split to their nitrogen applications versus all of it upfront. Of the 11 participating farmers in Pennsylvania, farmers saw an average yield increase of 17.6 bushels per acre and a 12 percent increase in nitrogen use efficiency. Check out more results here.

To enroll today and to learn more please contact our team! Eric Rosenbaum for Pennsylvania at 484-788-7263 or by emailing ericrosenbaum@rosetreeconsulting.com. For Delaware and Maryland contact Jenell Eck McHenry at 443-262-6969 or by emailing jenell.mdag@gmail.com. Sign-up is encouraged to be submitted by April 1st.

Funding is provided by the National Fish and Wildlife Foundation Chesapeake Bay Stewardship Fund. The Mid-Atlantic 4R Nutrient Stewardship Alliance was awarded a three-year grant for education, training, and cost-share to increase the implementation of 4R Nutrient Stewardship practices. Learn more about our work online at 4rmidatlantic.com.

Management Tips to Harvest High Quality Winter Forage

Jeff Semler, Principal Agriculture Agent
University of Maryland Extension, Washington County

Article adapted with permission from information provided by Tom Kilcer, certified crop adviser in Kinderhook, N.Y.

In most of our region, the warm temperatures have kick started the winter forage. This crop can give you the earliest and the highest quality forage for your livestock. Now is the time to add nitrogen and sulfur, which can save you on protein supplements by allowing you to harvest high-protein forage.

Yield potential was set last fall, depending on planting date and available nitrogen. These two factors generate the number of fall tillers that help set the yield potential for the following spring.

While planting date is the most important factor, there is still potential for economical yields so long as the stand came through winter.

1. Provide sulfur for more protein. Sulfur has long been an overlooked plant nutrient. Prior to the clean air act, our sulfur came in our rain. Sulfur is critical for protein formation and should be included with any nitrogen application to winter forage. For example, adding extra nitrogen — 115 pounds — without sulfur only provided 12% crude protein. Adding a lesser amount of nitrogen with sulfur provided 17% crude protein. For a field that did not get manure last fall (a major on-farm sulfur source) an effective ratio is roughly 1 pound of sulfur for every 10 pounds of nitrogen. This is good for all cool-season grasses in addition to winter forage grains, such as triticale.Sulfur is also critical for corn and especially sorghum, which can produce much higher protein in the forage.

2. Increase N application. Research has shown that even if you immediately incorporated manure the previous fall before planting, an application of spring nitrogen is still needed.

In one study, spring fertilizer application didn’t increase the spring yield of triticale on manured ground but it did raise the crude protein from 9% to over 19%, which can potentially save money on purchased protein.

Many farms apply between 75 and 100 pounds of nitrogen an acre in spring. Even if you applied manure prior to planting in the fall, it is suggested increase this to 125 pounds an acre to boost forage protein and save on purchased protein. Remember, a 3-ton dry matter yield at flag leaf stage will remove 192 pounds of nitrogen at 20% crude protein. What is not used by the winter forage will still be used by the following crop.

One caution, don’t try this higher rate on rye. Rye has limited tillering and produces a tall but thinner stand. It is very prone to lodging when more than 50 pounds of nitrogen an acre are applied.

Triticale is only two-thirds the height of rye and is resistant to lodging. Several university trials have found that triticale yields 35% higher than rye because of the higher tiller density.

3. Add an antivolatilization agent. It is highly recommended to add an antivolatilization agent in the spring. This will inhibit the urease enzyme from splitting the urea into ammonia that could be lost. Trials have found that urea loss in fields treated with an antivolatilization agent were 63% less than in fields that were untreated. The antivolatilization compound increases the chance of full return on your fertilizer investment.

4. Know when to harvest. For those new to growing winter forage, it is ideal to harvest at the flag leaf stage (stage 9) for optimum quality. Stage 8 does not have higher quality than stage 9, and you can get a substantial yield drag from harvesting too soon.

If temperatures are warmer than normal, push to harvest the forage at the flag leaf stage. Conversely, if it is at stage 8 and there is a week of rain forecasted, get it cut so you have quality forage.

 

Can Aboveground Pest Pressure Disrupt Nitrogen Fixation in Alfalfa?

Morgan N. Thompson & William O. Lamp
University of Maryland, Department of Entomology

Nitrogen is a critical nutrient for forage crop growth and quality. Typically, farmers need to apply additional nitrogen fertilizers to meet the nitrogen demand of crops. Nitrogen-fixing crops, however, do not require nitrogen fertilizer inputs, providing their own nitrogen supply through symbiotic interactions with soil microbes (rhizobia). Rhizobia induce the formation of root nodules in nitrogen-fixing crops, predominantly legumes, and extract inert nitrogen gas from the atmosphere to produce ammonium. In exchange for ammonium, legumes provide the rhizobia carbohydrates to fuel the microbe’s metabolism. Alfalfa is a leguminous forage crop that relies on symbiotic interactions with rhizobia to obtain nitrogen. As a perennial crop, alfalfa stands can last from 3-7 years and typically require no nitrogen fertilizer inputs, making alfalfa a sustainable and high-quality option for forage growers.

Pest pressure can decrease the economic viability of an alfalfa harvest. One particularly devastating pest of alfalfa in Maryland is the potato leafhopper (Empoasca fabae). Potato leafhoppers migrate northward from the southern United States every spring, making the timing of management in the northeast very difficult. Additionally, potato leafhoppers can utilize many alternative host plants, some of which are also of agroeconomic value, such as soybeans and several other fruit and vegetable crops, and leafhoppers can reproduce multiple times during the growing season. To protect alfalfa from potato leafhopper damage (termed ‘hopperburn’), insecticides are often the only option for growers. As a perennial crop, serious pest pressure in one growing season could impact nitrogen fixation in subsequent growing seasons, further accelerating economic losses for growers.

Figure 1. Amount of fixed nitrogen in alfalfa stems and leaves. * represents significant differences between treatments. No Nitrate = No Nitrogen Fertilizer, Moderate Nitrate = Nitrogen Fertilizer Applied; E. fabae- = No Leafhopper Pressure, E. fabae+ = Leafhopper Pressure.

Therefore, in recent field and greenhouse experiments, we sought to determine the effect of potato leafhopper pest pressure on nitrogen fixation in alfalfa. We predicted pest pressure would negatively impact plant growth and carbohydrate production, resulting in reduced nitrogen fixation by rhizobia and uptake of fixed nitrogen by alfalfa. We also predicted losses in nitrogen content of alfalfa due to pest pressure could be offset by nitrogen fertilizer applications. To test our predictions in a field setting, we planted four combinations of small plots: 1) Fixing Cultivar + Nitrogen Fertilizer, 2) Non-Fixing Cultivar + Nitrogen Fertilizer, 3) Fixing Cultivar No Nitrogen Fertilizer, and 4) Non-Fixing Cultivar No Nitrogen Fertilizer. Fixing and non-fixing alfalfa cultivars were utilized to compare plants reliant on both nitrogen fixation and soil nitrogen with plants completely reliant on soil nitrogen. We split each plot in half, applying cages with leafhoppers to one side and cages without leafhoppers to the other. We analyzed the amount of fixed nitrogen in aboveground plant tissue. Results from the field experiment contradicted our predictions, showing nitrogen fertilizer did not increase aboveground nitrogen content of alfalfa under pest pressure. Nitrogen fertilizer (Moderate Nitrate) also decreased aboveground fixed nitrogen content in plants with and without pest pressure (Fig. 1). Unfertilized plants (No Nitrate), in contrast, showed significantly increased amounts of fixed nitrogen content when under pest pressure (Fig. 1). These results contradicted our predictions and suggest alfalfa interactions with rhizobia play a role in helping plants withstand pest damage.

We also examined leafhopper-alfalfa interactions in a greenhouse setting. Here, we analyzed the response of two different cultivars of alfalfa: leafhopper-susceptible (Pioneer 55V50) and leafhopper-resistant (Pioneer 55H94). Nitrogen fertilizer treatments were applied to both cultivars, as well as cages with or without leafhoppers. Results indicate that additional nitrogen fertilizer did not increase the percent nitrogen of plants under pest pressure, regardless of the cultivar (Table 1).

Overall, we conclude leafhopper pest pressure decreases total nitrogen content of alfalfa across all four cultivars tested in both field and greenhouse settings. Amending soils with additional nitrogen fertilizer did not offset losses to leafhopper pressure and we do not recommend this as a management strategy to growers. In our field experiment, however, we found evidence that leafhopper pressure enhances aboveground fixed nitrogen content of alfalfa grown in soils without additional nitrogen. Rhizobia may play an unexamined role in the response of alfalfa to leafhopper pressure. Broader implications of our results highlight how pest damage may increase nitrogen fixation, which may benefit farmers interested in utilizing nitrogen-fixing cover crops.

Acknowledgements: Many thanks to the Western Maryland Research and Education Center staff and greenhouse staff at the University of Maryland aiding in the execution of these experiments, as well as members of the Lamp Lab. This study was funded by Northeastern Sustainable Agriculture Research and Education (Award Number GNE18-187-32231) and the Hatch Project MD-ENTM-1802.

Table 1. Systemic (shoots, crowns, roots) percent nitrogen content of susceptible and resistant alfalfa cultivars in the greenhouse. No Nitrogen Added = No Nitrogen Fertilizer, Nitrogen Added = Nitrogen Fertilizer Applied; Healthy = No Leafhopper Pressure, Injured = Leafhopper Pressure.

When it Comes to Nitrogen Leaching, Not All Cover Crop Practices Are the Same

Ian Goralczyk, Nathan Sedghi, and Ray Weil
University of Maryland, Department of Environmental Science & Technology

Cover crops are subsidized by taxpayers for use on more than 600,000 acres of agricultural fields in Maryland as part of an initiative to protect water quality and the Chesapeake Bay. As cover crops grow and take up nutrients, the water leaching from fields is cleaned up, especially with regard to nitrogen. However, the way that cover crops are typically managed may not be optimal for improving water quality. The Weil lab’s previous work has shown that the effectiveness of cover crops in reducing N leaching during the winter is dramatically affected by how early the cover crops are established, with cover crops planted in mid-October having little impact on N leaching compared to those planted a month earlier. The challenge is to find ways of getting cover crops established in early September, a time frame usually not possible with the typical practice of drilling cover crop seed after harvesting the corn or soybean cash crop. For this reason we studied a mixed species cover crop (radish, rye, and crimson clover) that was interseeded into standing soybeans canopies as compared to the standard practice of post-harvest drilling, and a no-cover crop control. We conducted the replicated experiment on two coastal plain fields with soils of contrasting textures formed in silty/clayey sediments, and in sandy sediments.

igure 1. Undergraduate researcher in the Weil Lab, Ian Goralczyk, installing a suction lysimeter for collecting soil porewater samples.
Figure 1. Undergraduate researcher in the Weil Lab, Ian Goralczyk, installing a suction lysimeter for collecting soil porewater samples.

This experiment was established at the Beltsville Facility of the Central Maryland Research and Education Center, with funding from Shore Rivers, LLC and the Maryland Soybean Board. The early planted cover was planted by broadcasting seed into a standing soybean canopy at leaf yellowing using a hiboy air-seeder on September 11, 2017. In each field, suction lysimeters were installed (Figure 1) to one-meter depth and samples were collected using a 85 kPa vacuum approximately every two weeks between December 17, 2017 and May 7, 2018. Soil pore water samples were filtered to remove particulate matter and frozen until they were analyzed for NO3-N and NH3-N on a LaChat® Flow Injection Analyzer.

One field had a silt loam surface texture and a clay loam subsoil (Russet-Christiana Complex). The other field had a loamy sand surface texture and sandy loam subsoil (Evesboro-Downer Complex). By utilizing fields of contrasting soil textural classes we can determine the effectiveness of these cover cropping methods with a range of soil conditions in order to broaden the scope of this study.

Cover crop use made a major difference in nitrate concentrations measured in the porewater collected at 1 m depth (Figure 2). Nitrate concentrations were reduced most where cover crops were established the earliest. As expected, the nitrate concentrations in the leaching water, as well as the impact of early cover crop establishment, were greatest on the sandy soil site.

While there were some individual samples that exceeded the EPA safe drinking water standard for nitrate-N (10.0 ppm), the average of all individual treatments was below this standard, and nitrate concentrations were consistently lower for the early interseeded cover crop treatment. A major reason why lower nitrate concentrations at one meter depth were observed for cover cropped plots is that the nitrate was taken up by cover crops roots and largely translocated to the aboveground plant tissue. This process captures the N before it leaves the potential rooting zone and recycles it to the surface soil where it may be released for use by future crops. This release could lead to decreased need for fertilizer nitrogen application to the following corn crop. Our data suggest that if similar cover crop interseeding practices (using aerial or ground-based methods) were applied on a large scale on commercial farms, the reduction in nitrogen loading to the Chesapeake Bay could be substantial. We can also conclude that early-planted cover crops are effective for reducing nitrate leaching on soils with a range of textural classes.

While these results are promising, it is important to note that they represent only one year out of a three year project, and that more data will be collected on different fields and with different cover cropping methods. We hope to provide farmers with guidance on optimizing cover crop species mixtures, planting dates and methods in order to enhance the impact of cover crops on nitrogen pollution while also improving soil health and farm profitability.

Figure 2. Nitrate-N concentrations in porewater from 1 m depth in fields of contrasting soil texture. Average of all sample dates during the 2017-18 winter-spring leaching season (N=33). Error bars are one standard error.
Figure 2. Nitrate-N concentrations in porewater from 1 m depth in fields of contrasting soil texture. Average of all sample dates during the 2017-18 winter-spring leaching season (N=33). Error bars are one standard error.