Proceedings
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1. US Midwest Dairy Manure Nutrient Observations 2012-2022Dairy manure is a source of organic nutrients with variable manure characteristics. This analysis drew 2012-2022 data from ManureDB, the manure and organic amendment database developed by the University of Minnesota. Thousands of solid dairy and liquid dairy manure samples across 2012-2022 were evaluated for book value comparisons, temporal trends, and regional differences for total N, NH4-N, P2O5, and K2O analytes. The only significant trend detect... N. Bohl Bormann, M. Wilson, E.L. Cortus, K.A. Silverstein, K.A. Janni, L. Gunderson |
2. Ammonium Thiosulfate as a Urease Inhibitor- A suggested MechanismA great deal of interest, ard sca~ controversy, has been generaw by my observations (Goos, 1985a; Goos, 1985b; Fairlie and Goos, 1986) that ammonium thiosulfate (ATS, 12-0-0-265) can inhibit soil urease activity when mixed with fertilizers such as urea-ammonium nitrate (UAN) . Preliminary field research (Gascho and Burton, 1987; Fox and Piekielek, 1987; Lamond et al. 1986) has shown some increase in crop yields or N uptah by adding ATS to surface-applied UAN. However, the use of ATS as a urease ... |
3. Beyond the Acre Furrow Slice: a New Era in Nutrient ManagementThe Midwest faces a pivotal shift in how we develop nutrient guidance for farmers. The long-running “build-up and maintenance” approach, built on decades-old soil-test methods, no longer aligns with today’s diverse and dynamic farming systems. Instead of anchoring decisions to soil depths tied to historical moldboard plow use, we should emphasize soil supply and plant uptake over time. Recommendations must be grounded in actual nutrient removal at harvest, on a site-by-... H.M. Brown |
4. Biological Nitrogen Suppliers for SoybeansSoybeans are known to require more N than most crops, largely due to the high N levels found in their seeds. The most important source of N for soybean plants is the biological N fixation process. However, high yields (above 70 bu acre-1) could limit the capability of this process to supply the plant's N demand. This study aims to investigate the use of non-rhizobial biological N suppliers, their ability to provide N to the soybean plants and potentially fill the N demand gap. The study w... V. Winnikes De Barros, S. Casteel |
5. Can Early Nitrogen and Sulfur Applications Sustain Soybean Yields After Cereal Rye?Cover crops such as cereal rye (Secale cereale L.) are widely promoted for their environmental benefits, including nutrient sequestration, reduced nitrate leaching, and soil conservation. However, their influence on subsequent soybean (Glycine max L.) yield and nutrient dynamics remains inconsistent, especially under varying nitrogen (N) and sulfur (S) fertilization regimes. Field trials were conducted during 2024 and 2025 across three sites in Central Illinois—Monmouth, Perry, and Urba... S. Canafoglia, G. Preza Fontes |
6. Can we Afford Not to Ridge Till?A typical farmer response to ridge till is that it is just another method of tillage. My contention is that it is much, much more than that. In my career in this I have had three cbjectives. One is to attapt to create as much balance between famkq ad the enviroment as possible. ?he second is to rrake farming profitable. The third is to make farming easier and fun. I believe with the proper approaches in regards to fertility, chemicals and water management along with the ridge till technique the... |
7. Closing the Yield Gap of Soybeans After Cereal Rye: How Limited S Application Can Affect Soybean PerformanceCereal rye is a common cover crop in the Midwest due to its overwintering biomass and soil fertility properties. Despite common adoption, research is still needed to improve soybean yield after cereal rye. Fertility management practices are needed to mitigate cereal rye immobilization of sulfur. These practices are integral for further cereal rye adoption at the farmgate. This study examines which combination of urea and/or gypsum is needed to enhance soybean yield in both cereal rye and no c... A. Antic, S. Casteel, S. Armstrong |
8. Compaction - K Fertility Interactions in Corn ProductionSoil compaction is recognized as a significant factor affecting yield in crop production today. The pressure to produce crops profitably has often led gruwers to farm greater acreages, with larger equipment under soil conditions which favor compaction. Effects of compaction are not limited to the surface lay- of a soil but often may be apparent cut much of the root zone. With the interest in soil compaction and its effects on crop growth, a research project was initiated to accomplish the fol lo... |
9. Corn Stem Nitrate N Content-Grain Yield Relationships and Their use as a Basis for Sidedress N Rate RecommendationsThe objectives of this study were to confirm the relationship between nitrate nitrogen (NO3-N) content of basal corn steras and grain yield in Iowa, to establish crltical levels of stem NO3-N content for dtaining various levels of mximum yield, and to perform preliminary calibration of yield responses to sidedressed nitrogen (N) at various levels of st-Rm NO3-N content. Six sites across Iowa with a wide range of physical and environmental conditions were selected. N fertilizer was applied prepla... |
10. Critical Soil Test Phosphorus for Corn: Updates and Method Comparison in KansasPhosphorus (P) fertilizer recommendations in Kansas are currently based on legacy correlation–calibration studies and guidelines that do not account for crop-specific requirements. This lack of precision creates uncertainty in fertilizer management, raising the risk of both under-application, which limits yield, and over-application, which increases costs and environmental risk. The objective of this research was to update the critical soil test phosphorus value (CSTV) for corn (Zea... G. Roa , D. Ruiz Diaz |
11. Cropping System Diversification Has Strong Short-term but Limited Long-term Impacts on Soil Phosphorus DynamicsCrop diversification provides several agroecosystem benefits, yet the effects of extended crop rotations and livestock integration on soil phosphorus (P) dynamics are not well understood. We examined the effect of three cropping systems: a corn (Zea mays L.)-soybean (Glycine max (L.) Merr.) rotation with synthetic fertilizer (2 year), a corn-soybean-small grain rotation with red clover (Trifolium pratense L.) and composted cattle manure as a fertilizer source (3 yea... J. Kovar, C. Crespo, J. Berkey, P. O'brien, W. Huang, M. Liebman, M. Mcdaniel |
12. Determining the Economic Optimum Nitrogen Rate for Different Cover Crop Systems Using On-Farm Precision ExperimentationSuccessful integration of cover crops into corn-soybean production systems requires adjusting interconnected management factors. Nitrogen (N) is a critical input in corn production, and because cover crops influence nitrogen dynamics, it is essential to evaluate both as an integrated system. To address this, field trials were established in two locations near Moultrie County, Illinois, in the fall of 2023 and 2024 as part of a four-year project (2024–2027) aimed at improving the underst... M. Dalla Betta, J. Jones |
13. Do Hybrids Differ in Response to Differential Levels of Nitrogen Fertilizer?In the absence of other limiting factors, maize yield increases with nitrogen fertilizer application to very high levels. In fact, researchers attempting to maximize maize production have reported a yield -rise at levels of N greater than 300 lbs/acre. Because there are many limiting factors in addition to nitrogen, nitrogen fertilizer must be mged to minimize costs and maximize response. In addition to mging the crup's proctuctivity, recent concerns about high levels of nitrates and other farm... |
14. Does Inoculant or Sulfur Improve Nitrogen Fixation in Soybean After Long-term Corn?This study evaluated the effects on nutritional dynamics and productivity in soybean, focusing on nitrogen and sulfur management in fields with more than twelve years of continuous corn in the state of Indiana (USA). Continuous corn systems are known to alter soil microbial activity, leading to a reduction in the nitrogen-fixing bacteria population, which affects the biological nitrogen fixation process in legumes, such as soybeans, which rely on those bacteria to meet their nitrogen requirem... A. Brun, S. Casteel, D. Quinn, R. Wilhelm |
15. Effect of Ammonia Knife Spacing on Corn YieldExperiments were conducted at DeKalb on a Drummer sicl, Dixon Springs on a Alford silt loam and Elwood on a Blaunt sicl to evaluate the effect of ammonia knife spacing at varying N rates and on different tillage systems on the yield of corn Nitrogen was awlied at 180 1bs N/acre at bath DeKalb and El& and at 210 lbs N/acre at Dixon Springs in the knife spacing by tillage study. In the rate by knife spacing by time of application study at DeKalb, the preplant nitrogen was placed under where the ro... |
16. Effect of Ammonium to Nitrate Rations of Fertilizers Applied at Various Times Throughout the Growing Season on Yield and Nitrogen Concentrationof CornA number of recent investigations have produced evidenm that the ionic form of N taken up by roots affects the growth of plants. While soil- plants generally take up rest of their N as nitrate, there is evidence that increasing the relative proportion of ammonium in the culture (or soil) solution can enhance growth and yield. Owing to difficulties in prevent* the rapid miaxbial conversion of ammonium to nitrate in soil, this response has nat been well demnstrated in a field situation. The object... |
17. Effect of Barley and Winter Pea Cover Crops on Nutrient Availability in No-Till CornCover crops are reported to have long-term soil health improvements, the first of which is reducing erosion. However, popular cereal cover crops, such as rye (Secale cereale), have the potential to cause a yield penalty in the following corn (Zea mays) crop. Legumes, such as Austrian winter pea (Pisum sativum), are thought to reduce this yield penalty in no-till systems. Additionally, sulfur deficiencies have been observed in some studies following cover crops. The ... E. Marsh, C. Lee |
18. Effect of Cover Crop Diversity on Nitrous Oxide Emissions from Corn–Soybean Rotations in Central IllinoisNitrous oxide (N₂O) is a potent greenhouse gas primarily emitted from agricultural soils, where nitrogen (N) inputs and soil conditions interact to drive microbial processes. Cover crops are widely promoted as a climate-smart strategy to improve soil health and nutrient cycling, yet their effectiveness in mitigating N₂O emissions may vary depending on species composition and functional diversity. This study evaluated the influence of cover crop diversity on N₂O emissions in a corn&ndash... N. Guzman |
19. Effect of Intensive Management Practices on Wheat Yields and ProfitabilityConsiderable interest in improving wheat yields and profitability has been shown throughout the U.S. over the past ten years. Much of this interest has resulted from the dramatic yield increases achieved by English producers during that time - an annual increase of 5.0 bushellacre per year (Figure 1). During that same time period, wheat producers in the U.S. have shown a much lower rate of increase in wheat yields - 1.02 bushellacre per year (Figure 2). Missouri growers have been no exception to... |
20. Effect of Manure Sources on Soil Phosphorus DynamicsPhosphorus (P) is essential for crop production, but it also causes water quality issues such as algal blooms. Crops typically utilize only 10-20% of applied P; the remainder accumulates in soil or is eroded/leached into water bodies, resulting in reduced fertilizer use efficiency and increased risk of eutrophication. This study evaluated the effects of different organic fertilization strategies on soil P pools across two sites in Ohio. Treatments included two manure-amended sites, one receiv... J. Singh, J. Ippolito, G. Labarge, M. Rakkar |
21. Effect of Three Tillage Systems on Soil Bulk Density and Porespace DistributionMany grain producers in Kentucky use a 3 crop in 2 year rotation of corn fol lowed by small grain-soybeans, and commonly no-ti1 1 the soybeans and corn in order to intensively use sloping land for continuous grain production. Because of the intensity of machinery traffic in this system, grtwxs. are concerned that continuw no-till management may cause compaction, and that such fields may need occasional primary tillage. In order to obtain information regarding this situation, we conducted a test ... |
22. Effects of Anhydrous Ammonia Application Timing on Corn Yield and ProfitabilityNitrogen (N) application timing is a critical decision for Illinois corn (Zea mays L.) producers balancing operational efficiency, economic return, and environmental stewardship. This study compared agronomic and economic outcomes of fall versus spring anhydrous ammonia applications across 19 central Illinois sites from 2013 to 2020, using a randomized complete block design with N rates from 0–361 kg N ha-1. Yield response to N was analyzed to determine agronomic optimum N ra... J. Jones, B. Link, E. Nafziger |
23. Effects of Nitrogen and Irrigation Management on Sugar Beet Yield and Nitrous Oxide EmissionsSugar beet (Beta vulgaris L.) is an important sugar-producing crop, accounting for about 55% of total sugar production in the United States. Optimizing nitrogen (N) and irrigation management is essential for achieving profitable and sustainable beet production. Excessive N application can lower sugar quality and increase nitrous oxide (N₂O) emissions, a potent greenhouse gas and ozone-depleting compound. This study evaluated the effects of irrigation and N fertilizer (urea) rates on su... S. De Silva, B. Maharjan |
24. Efficient Nitrogen Strategies for Hybrid Winter RyeEfficient nitrogen (N) management is essential to maximize hybrid winter rye (Secale cereale L.) yield. Given limited information on how N rates, application timing, and fertilizer sources affect production in the U.S. Midwest, yield responses were evaluated under various N management strategies. This experiment included a pre-plant application of 30 lb N ac⁻¹ in the fall, followed by spring applications to evaluate eight N rates (0–210 lb N ac⁻¹) and investigate the effec... M.L. Costa, J. Clark, V. Nunes, P. Sexton |
25. Emerging Trends from Wisconsin’s Nitrogen Optimization Pilot ProgramAccurately determining nitrogen (N) fertilizer requirements for crops is challenging due to the wide variability in landscapes and field management across the state. Adjusting nitrogen rates comes with a high level of risk considering over-application can reduce profits and negatively affect water quality, while under-application can prevent yield targets from being reached. Conducting field-scale, on-farm research is a practical approach to better estimating optimum N rates on a fi... M. Schauer, M. Ruark |
26. Evaluating Classification Methods for Phosphorus Responsiveness for Fertilizer RecommendationsField crop yield responses to fertilizer applications are often uncertain, and the likelihood of a response at a given site is typically determined using correlation-based soil test methods whose accuracy is not well established. The objective of this study was to evaluate three alternative approaches to classify field sites as responsive or non-responsive to phosphorus (P) fertilization in wheat. The methods tested were: (i) a linear-plateau correlation model, (ii) a linear-plateau correlati... D. Ruiz Diaz, S. Cominelli, J. Lacasa |
27. Evaluating Commercial Nitrification Inhibitors Under Variable Soil ConditionsNitrification inhibitors (NIs) are commonly used agrochemicals designed to slow the conversion ammonium to nitrate, which has the potential to reduce environmental losses of nitrogen and improve nitrogen fertilizer recovery efficiency. However, their efficacy can be highly variable and is dependent upon soil and environmental characteristics which can vary by geographic location and agricultural production system. This experiment involved a laboratory incubation designed to evaluate the perfo... R. Roth, A. Ludolph |
28. Evaluating Near-infrared Spectroscopy for Predicting Soil Chemical Properties in KansasSoil testing is fundamental for accurate fertilizer recommendations and effective nutrient management. However, traditional wet chemistry methods are time-consuming, labor-intensive, and costly. Near-infrared spectroscopy (NIRS) offers a faster and more sustainable alternative by estimating soil chemical properties from light absorption and reflection between 350 and 2500 nm. This study aimed to develop Kansas-specific NIR calibration models to evaluate the applicability of this technique for... S. Cominelli, D. Ruiz Diaz |
29. Evaluating Soil Health Indicators in Response to Tillage, Crop Rotation, and Cover CroppingSoil health is shaped by management practices that influence soil physical, chemical, and biological properties. Conservation practices such as reduced-disturbance tillage, cover cropping, and diverse crop rotations are increasingly promoted for improving soil structure, nutrient cycling, and microbial activity. However, the extent to which these practices interact and whether newly adopted no-till systems show similar benefits to long-term reduced tillage remains unclear. This study evaluate... S. Mesman, J. Clark, V. Nunes, P. Sexton |
30. Evaluating Soybean Yield and Soil Fertility Response to POLY-4 As a Sulfur and Potassium SourceBoth sulfur (S) and potassium (K) play an essential role in soybean growth and metabolism, immunity against insect-pest and improving yield quality and quantity. Reduction in atmospheric deposition of S in soil in recent years has increased the risk of S deficiency in crops. POLY-4 is a novel S and K source containing 19% S, 14% K2O, 17% CaO, and 6% MgO with properties like slow nutrient release and high nutrient use efficiency. It can be used to address the issue of S deficiency in plants. A... R. Kaur, K. Nelson, G. Singh , G. Kaur |
31. Evaluating Spatial Attribution for Continuous Improvement of Fertilizer RecommendationsThe theory behind precision agriculture is driven on the improvement of every acre. While spatially driven recommendations have been practiced for greater than 30 years, the benefits of precision agriculture have largely not been realized. Today’s precision fertilizer recommendations have generally utilized traditional attributes (for instance: soil test phosphorus, soil test potassium, and in some application recommendations, other analyzed attributes from soil test evaluat... W. Berg |
32. Fate of 15N-Labeled Urea Applied In-season for Corn in Eastern North DakotaNitrogen (N) fertilizers represent a major investment for North Dakota cropping systems as evidenced by the 890,000 tons of N used by producers in 2024 alone. If these inputs are to be beneficial to the producer and not harmful to the environment, they must be managed efficiently. To evaluate the efficacy of split-N applications, 15N-labeled fertilizer was applied to three different soil types in eastern North Dakota, including an irrigated sand, a smectite rich clay, and clay loam... M. Culpitt, K. Griesheim |
33. Fertilizer Derived Nitrogen Dispersion in Minnesota Corn with Rye and Kura Clover Cover CropsWhile ideally all fertilizer nitrogen (N) is utilized by crops, much can be lost to the environment as nitrate (NO3), nitrous oxide (N2O), or ammonia (NH3). To enhance agronomic systems and mitigate environmental N dispersion, best management practices can be utilized. Here, urea was applied to continuous corn at 250 kg N/ha or a 0 kg N/ha control, and with select cover crops (no cover, winter rye, kura clover) to assess practices that may result in optimal fe... J. Kastenbauer, F. Fernández, V. Sharma, R. Venterea, J. Spackman |
34. Field Correlation and Calibration of Soil-Test Phosphorus and Potassium for Corn and Soybean in IllinoisEffective phosphorus (P) and potassium (K) soil-test interpretation and fertilizer guidelines require each soil test to be field correlated with crop yield response to fertilization and calibrated to provide expected response probabilities. University of Illinois P and K guidelines require updates to reflect routinely used soil-test methods and current cropping systems. Field studies were established at seventeen sites across Illinois to correlate soil-test P and K with corn and soybean respo... F. Bardeggia, J. Jones |
35. From the Ground Up: a Farmer-Led On-Farm Research Evaluating the Potential of a New Fertilizer Source for Nitrogen in Pastures for MissouriThis research is a part of a transdisciplinary network of farmers leading on-farm research and innovation groups across Missouri, where farmers are leading the design and implementation of nitrogen (N) fertilizer treatments. The Objective of this on-farm research trial in southwest Missouri is to determine whether green lightning fertilizer technology can fulfill the N requirement of pasture in a more economical and sustainable way than the conventional sources of N. The cost of N f... K. Deep, R. Carson, G. Singh, J. Vredenburgh |
36. FRST Lime Project: Results of Pilot Study of Lime Source, Lime Rate and Incubation Time on Neutralization of Soil AcidityManagement of soil acidity plays a critical role in the agriculture across North Central Region. The Fertilizer Recommendation Support Tool (FRST) group has launched a national project to develop new lime recommendations and has collected 144 soils of which 38 soils from the North Central Region. A pilot lime study was initiated to assess the effect of lime source, lime rate and incubation time on neutralization of soil acidity. Three acid soils were selected from the Agricultural Proficiency... B. Miller |
37. How Do Cover Crops, Nitrogen Rate and Cropping System Affect Nitrate Loss in Tile Drainage Water?A field research study was conducted on clay loam soil in Waseca Minnesota. The objectives were to quantify the effects and interactions of cover crops, nitrogen (N) fertilizer rates and cropping system on corn production and nitrate-N concentration and loss in tile drainage water. Cover crop treatments [cereal rye and a blend of annuals (oat, forage pea and radish)] were drilled soon after corn silage harvest each fall. Nitrogen treatments were split-applied at planting and V3 growth stage. ... J. Vetsch, A. Cates |
38. Impact of Ammonia Reduction Management Practices in Land Applied Manure on Nitrogen Losses and Nitrogen Use EfficiencyDairy manure is a valuable nitrogen (N) source in crop production, but N losses through volatilization and leaching diminish its nutrient value and pose environmental risks. Proper manure management practices can enhance nitrogen use efficiency (NUE) and mitigate these environmental concerns. This ongoing two-year field study evaluates different manure application methods and assesses their tradeoffs regarding N leaching and NUE. The study involves six experimental treatments, each applying 9... J. Bukomba, R.A. Larson, M. Ruark, X. Zhu-barker, N. Rayne |
39. Impact of Phosphorus Source and Timing on Corn Yield and Root GrowthPhosphorus (P) management is critical in maize production due to limited mobility, solubility, and stratification in soils. This study evaluates P application techniques with regard to maize grain yield, total P uptake, and root distribution. Our hypothesis was that applying P as a side dress in a low P soil at a low dose equal to plant uptake can compensate for not maintaining soil test P at the critical level, providing sufficient P during peak demand and sustaining high yields. A gre... A. Beltrame, C. Penn, D. Quinn, M. Williams, C. Zhang |
40. Impacts of Management Practices and Soil Properties on Free-Living Nitrogen Fixation in Southeastern South DakotaModern agriculture relies heavily on synthetic nitrogen fertilizer, raising environmental concerns due to overuse. Biological dinitrogen (N2) fixation offers a sustainable alternative, with free-living diazotrophs playing a crucial role alongside well-known symbiotic nitrogen-fixing bacteria. Recently, interest in free-living nitrogen fixation (FLNF) has grown due to its potential contribution to sustainable agricultural practices. However, there is limited scientific data on FLNF ... L. Galvan Nuevo, A. Blume, V. Nunes |
41. Improved N Use Efficiency for Wheat in Southwest IndianaAbout one-third of the wheat acreage in Indiana is grown in southwest Indiana. During most years this area of Indiana receives exoessive precipitation during the late winter and spring gruwth period for wheat. This presents problems with losses of available soil nitrogen (N) through leaching and/or denitrification and law uptake of N by the crop even on fields which have been well-fertilized. These experiments were condtucted in 1986 and 1987 to evaluate fall, mid-winter and late-winter topdress... |
42. Improving Corn Grain Yield and Reducing Nitrate-N Leaching with Urease and Nitrification InhibitorsSustainable corn (Zea mays L.) production requires proper nitrogen (N) management to optimize yield and minimize negative impacts of N losses on water quality. Nitrification inhibitors could be a viable strategy to synchronize N availability and corn N demand and decrease N loss through nitrate-N leaching. A field study was laid out in a randomized complete block design with five replicates at the Belleville Research Center (2023-24) and the Agronomy Research Center (2024-25), IL, wi... S. Koduru, O. Guzel, J. Mcgrath, M. Javid, O. Ola, E. Brevik, A. Sadeghpour |
43. Industrial Hemp Response to Nitrogen Applications in MissouriIndustrial hemp (Cannabis sativa L.) is gaining attention as a multipurpose crop for fiber, grain, and biomass, but research-based region-specific guidelines on nitrogen (N) management are limited. To address this gap, field experiments were conducted at two locations (Albany, Novelty) in northern Missouri in 2024 & 2025 to evaluate the effects of N applications on industrial hemp growth, biomass, and grain yield. The experiments were laid out as a randomized complete block ... A. Nain, G. Kaur , K. Nelson, G. Singh, M. Davis |
44. Influence of Nitrogen Fertilization Frequency and Rate on Nitrous Oxide Emissions in Winter WheatManaging nitrogen (N) fertilizer effectively is important for reducing nitrous oxide (N2O) emissions in farming systems. This study examined the effect of N application frequency and rate on winter wheat (Triticum aestivum L.) grain yield, total N₂O emissions, and yield-scaled N₂O emissions. The experiment was conducted at the Agronomy Research Center (ARC), Southern Illinois University, Carbondale. A randomized complete block design (RCBD) was used ... O. Ola, O. Guzel, K. Gage, K. Williard, J. Schoonover, S. Mueller, E. Brevik, A. Sadeghpour |
45. Influence of Nitrogen Management and Precipitation on Sorghum Nitrogen Use Efficiency in KansasGrain sorghum (Sorghum bicolor L. Moench) is a key crop in Kansas which can benefit from optimized nitrogen (N) management that enhances yield while minimizing N losses. Understanding the relationships among physiological efficiency (PE), recovery efficiency (RE), and agronomic efficiency (AE), as well as their interactions with climatic factors such as precipitation, is essential for improving nitrogen use efficiency (NUE). Experiments were conducted across five r... M. Platero, D. Ruiz Diaz |
46. Influence of Soil Amendments and Topographic Position on Winter Wheat Heavy Metal UptakeField crop heavy metal accumulation poses a major challenge for reducing food contamination and is governed by complex interactions between soil physical and chemical properties, climatic conditions, and intrinsic plant traits. Addressing these challenges requires an understanding of heavy metal accumulation during crop development and effective pre-harvest field mitigation strategies. Two winter wheat (Triticum aestivum L.) field studies were conducted in Michigan focusing on 1) fer... K. Steinke, M. Suplito, Z. Hayden |
47. Influence of Soil Nitrate Nitrogen and Fertilizer Nitrogen on Wheat Grain Yield and ProteinWheat producers have recently shown a great deal of interest in grain protein levels. 'Ikis interest has developed prkily because of the relatively lqe protein premium available the last several years (Table 1). Nitrogen is a primary component of protein and needs to be added for most soils to produce high yielding, high protein wheat. The objectives of this study were to detennhe the effects of soil nitrate nitrogen and fertilizer nitrogen on wheat grain yields and protein levels. ... |
48. Integrating NDVI and Plant Tissue Analysis As Decision Support Tools for Nutrient Management in Winter WheatEfficient nitrogen (N) management is critical for improving winter wheat grain yield and protein content while minimizing costs and environmental risks. Remote sensing indices, such as the Normalized Difference Vegetation Index (NDVI) and physiological indicators, like flag leaf N content, have been proposed as predictors of crop performance that could support in-season N management decisions. This study evaluated the relationships between NDVI measured at multiple growth stages, flag leaf N ... J. Leiva, D. Ruiz Diaz |
49. Interaction of Potassium Fertilization and Row Width for SoybeansIn the past several years the row width of soybeans has decreased substantially. As row width decreases the amount of soil between rows for soybean roots to explore and from which to extract nutrients has decreased. Also many acres in the Midwest have little or no fertilizer added in the soybean year but rely on residual nutrients left from the previous crop. In this study the effect of row width and method of potassium fertilization for soybeans was investigated. ... |
50. Interpreting Soil Health Test Results to Guide Management for Missouri Row CropsSoil health determines long‑term productivity, nutrient cycling, water retention, and resilience in row‑crop systems. Missouri-specific, data-driven framework for interpreting six complementary soil health indicators—total organic carbon (TOC), permanganate-oxidizable carbon (POXC), 3-day soil respiration, wet aggregate stability (WAS), autoclaved citrate-extractable (ACE) protein, and potentially mineralizable nitrogen (PMN)—was developed by the University of Missouri Soil He... G. Singh , K. Nelson, M. Parvej, D. Brandt, R. Myers |
51. Investigating Potassium Fertility in Indiana: K Rates and Nutrient InteractionsAdequate potassium (K) nutrition is critical for optimal plant growth and yield production in both corn and soybeans. Ongoing trials across the state of Indiana have been investigating K rate response in corn and soybeans in different environments. Treatments range from 0-180 lbs K2O/ac as potash. Results from these studies will be discussed. Additionally, new in 2025, NxS and NxK trials were conducted to investigate the effect of K nutrient interactions on corn yield. Treatments i... D. Quinn, A. Helms, M. Bourns |
52. Investigating the Need for Sulfur for Kentucky Wheat ProductionSulfur (S) deficiencies in Kentucky wheat production are increasing due to a reduction in atmospheric S deposition, greater removal in grain and forage, and less S contamination in phosphorus fertilizers. The University of Kentucky currently does not provide S recommendations based on S soil test results. This is largely due to the Mehlich 3 soil test extractant not being correlated or calibrated for S response in Kentucky crops and the lack of S responsive fields. Surveys and studies were co... E. Ritchey, J. Grove |
53. Iowa's 1987 Groundwater Protection ActThe law is the result of public concern about contamination of Iowa's groundwater resources. Data from all over the state have shown that agricultural chemicals are finding their way into -ter. The law calls for spending $64.5 million over 5 years on programs to prevent groundwater contamination from agricultural chemicals, sinkholes, agricultural drainage wells, municipal and irdustrial wastes, landfills, household chemicals, and buried chemical and petroleum storage tanks. Three fourths of the... |
54. Linking Soil Properties and Weather Variability to Nitrogen Fertilizer NeedsSoil Nitrogen (N) availability is known to be affected by weather and soil characteristics. Current fertilizer recommendations are generally based on yield goals, soil type, and past productivity; however, these methods frequently fail to account for the constantly changing interactions between soil biological, chemical, physical and weather variables that influence N availability. This limitation increases uncertainty in estimating the economic optimum nitrogen rate (EONR), potentially reduc... S. Dangal, J. Clark, P. Kovacs, V. Nunes, C. Graham |
55. Nitrogen Effects on Forage Utilization and Economic Returns in Grazing and Haying SystemsForage productivity and profitability are essential in both grazing and haying systems. This study evaluated haying and rotational grazing systems and nitrogen rates compared to overseeding birdsfoot trefoil (Lotus corniculaatus; BFT) on an Armstrong Loam (Aquertic Hapludalfs). Forage biomass was consistently higher under grazing, with its advantage widening as N increased. Both systems displayed diminishing marginal returns, but grazing achieved greater fertilizer efficiency, produc... E. Oppong Adjei, R. Carson, J. Lory, K. Nelson |
56. Nitrogen Fertilizer Application Consultation Tool (N-FACT)The N-FACT is a decision support web tool that leverages data from the Iowa Nitrogen Initiative on-farm nitrogen rate trials with cropping systems modeling. The web tool was released in February 2025 (https://n-fact.ag/start). The web tool summarizes results on optimum nitrogen fertilizer rate for corn from hundreds of on-farm trials across Iowa. Additionally, the web tool allows users to select a county, crop rotation, planting date, fall... S. Archontoulis |
57. Nitrogen Management for no-till Grain SorghumField experiments evaluating the effects of nitrogen management for no-till dryland grain sorghum were coacted in 1985 and 1986. Nitrogen rates (0, 50, 100 lbs N/A and placement methods for urea ammonium nitrate solution (UAN) have been evaluated in eastern Kansas. Placement methods have included surface broadcast, surface banded, pressure injected, and knifed. Results to date shm that nitrogen consistently increases yields and tissue and grain N contents, and that method of UAN placement produc... |
58. No-till Corn Response to N Fertilizer Sources and Placement Methods- A Summary of Southern Illinois ResultsExperiments were conducted in southern Illinois from 1984-1986 to evaluate the placement efficiency of several N fertilizers used in no-till corn production. Such information has become of meaningful importance as producers strive to obtain the greatest possible returns from their N fertilizer investment and to obtain yields and a level of profitability equal to that of more conventionally produced corn. Also, in the near future, no-tillage will become an important tool for many farmers in south... |
59. Optimizing Nitrogen Application in Corn with and Without a Nitrification InhibitorDetermining an accurate nitrogen (N) recommendation for corn production presents significant challenges due to its complexity with N transformation and losses. A careful diagnosis and decision making is required for optimizing the N management in corn. Therefore, a three-year (2023-2025) field study was conducted to evaluate the effects of varying nitrogen (N) application rates and timings with the use of a nitrification inhibitor (NI) on corn grain yield and productivity. The study was arran... R. Paul, G. Singh , K. Nelson, G. Kaur , M. Parvej |
60. Optimizing Nitrogen Inputs in Malting Barley ProductionIn 2024, North Dakota produced 14.6% of the United States 144 million bushels of barley. Nitrogen (N) availability is a key factor influencing production and as sustainability becomes a priority, reducing greenhouse gas (GHG) emissions through enhanced efficiency fertilizer is essential. This study evaluated the effect of N application source on spring barley (Hordeum vulgare L.) grain yield and quality, as well as estimating N use efficiency (NUE). Field trials took place in 2025 at... B. Goettl, M. Martinez De Souza |
61. Optimum N Rates for Corn Production as Influenced by Crop RotataionFertilizer N efficiency in corn production has become a'hot' research topic in the 1980's. Increased concerns of nitrate-N entering the groundwater and the potential for improving the profitability of corn producers are the impetus for fine-tuning fertilizer N recarmnendations. Crop production factors such as improved diagnostic techniques, full utilization of symbiotic N fixation, and crop rotation have been gaining widespread research support throughout the United States. The adoption of crop ... |
62. Phosphorus Fertilizer Management: Implications on Crop Yields and Soil P BudgetsRecent volatility in fertilizer prices, declining commodity values, and increasing water quality concerns have intensified scrutiny around phosphorus (P) management decisions in Ohio. In response, we initiated a field trial to evaluate crop yield response and soil phosphorus budgets under various P application strategies within a corn–soybean rotation during the 2024 and 2025 growing seasons. The study investigated two P application timings (fall and spring), two fertilizer sources (tri... M. Rakkar, B. Robinson |
63. Picking the Right Nitrogen Recommendation Tool to Improve NUE and Water Quality in NebraskaThe comparison of static versus dynamic nitrogen (N) recommendation tools has gained significant attention for enhancing N management in the U.S. Midwest maize production. However, both approaches have limitations in performance under variable field conditions. This two-year study (2021–2022) evaluated the agronomic, environmental, and economic outcomes of a static Nebraska Yield Goal (NE YG) tool against four dynamic N tools: Maize-N, canopy reflectance sensing, Granular, and Adapt-N. ... J. Iqbal, A. Singh |
64. Predicting Fertilizer Nitrogen Requirements for Corn in OntarioThe nitrogen fertilizer requirement of a crop under field conditions is influenced by numeraus factors including soil, climate and managanent variables. Most of these factors are very difficult, if not impossible to predict in advance. The major factors influencing nitrogen fertilizer nquhment are (Gch and Haynes, 1986); 1. the requirement of the crop for N as determined by its yield (or yield patential) , 2. the availability of fertilizer N or the fertilizer use - efficiency, and 3. the amount ... |
65. Predicting Nitrogen Response by Winter Wheat Using Soil Health and Soil Microbiome IndicatorsEfficient nitrogen (N) management is critical for improving profitability and sustainability in winter wheat production systems of western South Dakota, where soils and growing conditions vary widely. Current fertilizer recommendations rely heavily on soil nitrate-N, often overlooking contributions from organic N sources and soil biological activity. This project aims to refine N fertilizer recommendations by integrating soil health indices (SHIs) and soil microbiome analysis as predictors of... C. Graham, R. Jain |
66. Preplant vs. Weekly Applications of N-P-K FertilizersMany studies have compared time of fertilizer application to corn, but few have looked at weekly applications of complete N-P-K fertilizers. Often only one nutrient is looked at individually making sure that the other nutrients of concern are adequately supplied. In some instances the ratio between the nutrient in question and other nutrients may be greatly out of proportion, thus resulting in an imbalance ard less than maximum response. Is it possible to add N-P-K nutrients in a certain ratio o... |
67. Role of Winter Rye Cultivar and Seeding Rate in Managing Residue and Nitrogen Availability in Corn Cropping SystemsWinter cereal rye (Secale cereale L.) (WCR) is the most widely used cover crop in Illinois and is recognized as one of the most effective in-field practices to reduce nitrate-N and phosphorus (P) losses to the Mississippi River Basin (MRB). However, adoption of WCR prior to corn (Zea mays L.) remains limited due to challenges such as stand establishment and nitrogen immobilization. Management strategies, such as selecting appropriate cultivars and optimizing seeding rates, m... S. Babaei, C. Kula, Y. Samadi, E. Brevik, A. Sadeghpour |
68. Sensor-based Nitrogen Management Affects Corn Production and Environmental N FootprintsTo improve air and water quality, nitrogen (N) management in corn production systems should shift from the current N decision support system [maximum return to N (MRTN)], which suggests a single rate N addition, to sensor-based (GreenSeeker) active N management (variable N rate approach). Single rate N recommendations often result in under- and over-N addition and either increase environmental N losses or cause corn yield penalty. Our objectives were to evaluate corn optimum nitrogen N requir... A. Sadeghpour, O. Guzel, M. Guzel, J. Mcgrath, O. Adeyemi, E. Brevik, S. Koduru |
69. Soil Health Responses to Interseeded Cover Crops and Nitrogen Strategies in the Northern Corn BeltCover cropping and nitrogen (N) management are often promoted for improving soil health, yet their combined influence under interseeded systems in temperate regions remains less understood. To address this gap, a field study was conducted in South Dakota at two no-till corn–soybean rotation sites (Brookings and Beresford) established on clay loam soils. Cover crop treatments included a no cover, a single grass species, and a multi-species mixture of grass and broadleaf species interseed... J. Clark, S. Kodali |
70. Soybean Response to Tillage, Row Spacing and Nutrient Management Practices in Southern IllinoisConservation tillage improves long-term soil health and water quality but may reduce early soybean (Glycine max L.) growth due to cooler, wetter soils and limited nutrient availability. This study evaluated integrated management strategies, including tillage, row spacing, and starter nitrogen (N) and sulfur (S) fertilization, to optimize soybean performance under Illinois conditions. Field trials were established in 2024 in southern Illinois. Two split-plot experiments were conducted... E. Brevik, A. Sadeghpour, F. Rolle, D. Schaefer, G. Preza Fontes, M. Javid |
71. Soybean Yield Response to Nitrogen and Sulfur Starter Fertilizers Under Conservation TillageContext: No-tillage and cover crops adoption remain limited across the U.S. North Central region due to concerns about potential yield penalties in cash crops. High residue levels can slow soil warming and mineralization and promote nutrient immobilization, often leading to limited early-season nitrogen (N) and sulfur (S) availability for soybean. Objective: Evaluate soybean grain yield response under different tillage systems and assess the potential of N and S starter fe... F. Rolle, G. Preza Fontes, D. Schaefer, J. Vossenkemper |
72. Technology, Innovation, and the Future of Soil FertilityThis panel will focused on how technology is being used in the practice of soil fertility and nutrient management. Panelists will also discuss how they’ve incorporated new and old soil fertility concepts into their approach to guiding fertilizer use. Lastly, we will discuss where soil fertility is going as a scientific discipline. ... H.M. Brown, W. Berg, R. Mullen |
73. Terrace Construction Effects on Soil Fertility, Texture and Apparent Electrical ConductivityThe Midwestern United States is extensively dominated by sloping terrains, where terraces are recognized as a tool to minimize soil erosion. The process of terrace construction involves heavy machinery and extensive soil profile manipulation, which may alter soil fertility and texture. This study evaluated the changes in soil fertility, texture, and apparent electrical conductivity (ECa) following the construction of eight broad-based terraces in northern Missouri. Geo-referenced soil samples... C. Bansal, G. Singh , G. Kaur , K. Nelson |
74. The Effects of Phosphorus and Potassium Application on a 14-year-old Miscanthus × giganteus StandMiscanthus × giganteus (miscanthus) is a perennial C4 grass grown for renewable bioenergy and bioproducts. While miscanthus is often considered to have low nutrient requirements, the need for fertilization remains poorly understood, particularly in mature stands. This study aims to provide insight by evaluating for potential phosphorus (P) and potassium (K) limitations in a 14-year-old miscanthus stand in central Iowa that had received no prior fertilization. The experiment fol... J. Studt, A. Larson, A. Vanloocke, M. Mcdaniel, E. Heaton, N. Boersma |
75. The Future of Soil Fertility - My Two CentsThis presentation will provide information of what a large cooperative is currently providing customers in the realm of nutrient management. Additionally, some insight will be provided on how other aspects of nutrient management (global markets, production technologies, etc) are being evaluated. Finally, some general ideas will be shared regarding the future needs of the retail sector along with some research ideas. ... R. Mullen |
76. The Growth of MEY in Spring Wheat CountryAny ag orientated news source looked at in recent weeks in North Dakota or western Minnesota has had some kind of a MEY related story. The MEY usually has been identified as 19naximum economic yield," but recently some use of I1most efficient yield" has been seen. Yes, spring wheat country has a new buzz acronym - MEY. How did such a buzz term for tbis amount of press/news coverage develop in the spring wheat region? The kickoff for MEY club deve1-t ocaured on November 25, 1986. Before that was ... |
77. The Impact of Shifting from N-based to P-based Manure Management on Corn Silage Yield, Quality, P Balance, and Soil Test PDairy farmers often apply liquid manure to corn (Zea mays L.) for silage to meet N needs (N-based) which results in over-application of P and increased soil test P (STP) levels. A solution to this manure management is switching from N-based to phosphorus (P)-based (P removal based) manure management and supplementing N need with inorganic fertilizer. Intensifying corn for silage rotation with cereal rye (CR; Secale cereale L.) as a forage source could further decrease STP, e... G. Burkett, E. Brevik, S. Babaei, O. Adeyemi, A. Sadeghpour |
78. The Manitoba Greenhouse Gas Assessment ToolMethane (CH4) and nitrous oxide (N2O) are potent greenhouse gases (GHGs) emitted by agriculture. Manitoba Agriculture has developed an educational GHG assessment tool that allows farmers to evaluate annual emissions of these GHGs from their practices and explore the impact of changing practices. The first phase of the GHG assessment tool consists of annual estimates of N2O and CH4 emissions from soil and crop management practices, livest... P. Loro, M. Riekman, C. Sawka |
79. Two-sided Banding of Nitrogen and Sulfur Fertilizers Improves Maize Yield and Nutrient Use Efficiency in Midwestern Cropping SystemsEfficient fertilizer management is essential for maximizing crop yield while minimizing environmental impacts. Optimizing fertilizer placement is a key strategy for improving nutrient recovery and synchronizing nutrient availability with crop demand. Traditionally, fertilizer banding in Midwestern maize (Zea mays L.) systems is done on one side of the plant. This study evaluates the impact of two-sided banding of nitrogen (N) and sulfur (S) fertilizers on maize yield and nutrient use... A. Yakubu, A. Ludolph, A. Diop, A. Yakubu, R. Roth |
80. Understanding Wheat Head Counts Effect on YieldWheat (Triticum aestivum) is grown in many parts of the world, with soft red winter wheat (SRWW) being the most popular type grown in Kentucky. Wheat is the fourth most economically important crop in Kentucky and is used in a variety of food products as well as in feed for livestock. Crop scouts reported wheat head counts above the current University of Kentucky threshold for head counts needed to maximize yield. Wheat in other states north reported higher head counts than those obse... A. Mutter, C. Lee |
81. Updating Oat Nitrogen Fertilizer Rate GuidelinesThe current yield-goal based system for calculating oat N rate recommendations in SD has not been evaluated for accuracy recently. There are two main N rate recommendation systems used in the U.S.–Yield goal and maximum return to N (MRTN). Therefore, the objective of this project was to 1) evaluate the accuracy of the current yield goal-based equation and 2) evaluate the accuracy of using the MRTN approach for predicting N rate requirements. Twenty-eight oat N rate response trials were ... J. Clark, D. Karki, A. Bly, P. Sexton |
82. Water Quality Issues and Activities in MinnesotaWithin the last few years there has been considerable public concern over the occunrence of nitrates (NO;) in bath ground and surface waters. ?his is especially significant since 50% of drinking water for the U.S. tames fm g-muthter supplies and this increases to 85% in the rural areas (CAST, 1985). The issue has at tirrres becaw emotioml and fingers have been pointed regarding the cause of nitrates in our water supply. Consequently, steps are being taken to establish the relationship between N... |
83. Water Quality Issues in NebraskaThe primary water quality issue in Nebraska at this the is related to groundwater as opposed to surface water. Groundwater provides irrigation for over 7 million acres of land in Nebraska and is the drinking water source for almost a1 1 of Nebraska's domestic and municipal water users. In rural areas groundwater provides about 85% of the drinking water (Cast, 1985). Numerous reports of groundwater contamination led to its emeqence as a major environmental issue for the 1980,s. Govenrment agenci... |
84. Winter Wheat Residue Management Affects Corn Grain Yield and Nitrogen RequirementWinter cereal cover crops are effective in reducing the nitrate-N (NO3-N) leaching from corn (Zea mays L.) and soybean (Glycine max L.) fields. An experiment was conducted as a randomized complete block design with split plot arrangement and four replicates to study wheat (Triticum aestivum L.) cover crop management practices on corn grain yield and nitrogen (N) requirement (economic optimum N rate; EONR). The main plots were four cover crop (CC) treatmen... F. Adeyemi, O. Adeyemi, E. Brevik, A. Sadeghpour |