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1. Effect of Nitrogen Fertilizer Placement and Sources on No-till CornNo-tillage production of corn can lead to a number of savings for growers including costs of time, machinery, labor, and energy. However, savings of soil and water are perhaps the most important attributes of no-tillage production on the sloping, erosion-prone soils found in southern Illinois, Indiana, Missouri, and Kentucky. Producer acceptance of no-tillage has not been overwhelming. Prob- lems in achieving acceptable stands, difficulties in adequately con- trolling pests of all types, especially... |
2. 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 southern... |
3. Phosphorous Management for Wheat ProductionProfitable wheat production depends on many factors, including a sound phosphorus (P) management program. Except for sunlight and water, soil fertility generally represents the most limiting factor in crop yields. Even with perfect weather and climatic conditions, a farmer that does everything right except to meet the nutrient needs of the crop will never reach optimum yield potential. Water, N, and P are generally the dominant yield limiting factors for wheat in the United States. Potassium, S,... |
4. Phosphorus Management on Extremely Acid Soils in South Central KansasResearch was conducted to evaluate the effectiveness of phosphate fertilizer in reducing the toxicity of soluble aluminum (Al) on very acidic soil for production of winter wheat. Banded P fertilizer increased wheat grain yields significantly with the response being greater on unlimed compared to lime conditions. Based on the findings of this research coupled with Oklahoma State University research, banded P is an alternative to liming for wheat production on extremely acidic soils with considerable... |
5. Site-Specific Prediction of Soybean Nitrogen ContributionsSoybean has long been recognized for its nitrogen (N) contributions and yield enhancing effects in crop sequences. Soybean N credits in the Midwest range fiom 20 to 40 Ib of Nlacre (Kurtz et al., 1984). Several Midwestern states recommend a legume credit of 40 Ib of Nlacre following an average crop of soybean. Current Wisconsin recommendations suggest a reduction in nitrogen fertilizer rates for corn following soybean of 1 Ib N hushel of soybean yield up to a maximum credit of 40 Ib Nacre (Kelling... |
6. Assessing the Variability of Corn Response to NitrogenBecause results of experiments designed to test the response of corn to N rate tend to vary considerably with the environment. repetitions of such studies over time are essential. It is not clear, however, what number of repetitions are needed in order to deduce sound recommendations for application of N fertilizer to succeeding crops. We used the results from 16 years of a crop rotation x N rate study conducted at Monmouth, Illinois to assess the effect of duration of such an experiment on the stability... |
7. Soil and Site Factors Responsible for Yield Variations in Two Southern Illinois Farm FieldsYield variability within a field is largely influenced by the soil physical. chemical. and topographic features of that field. On-farm field research studies were conducted from 1997 through 1999 on two southern Illinois farm fields (one in Jefferson County and the other in Pope County) with varying soil physical, chemical, and topographic features to determine which factors most influenced crop yield variability. Each location was GPS-gridded utilizing a grid cell size of 0.45 acres. Detailed topographic... |
8. Sulfur Responses and the Wisoconsin Alfalfa Sulfur SurveyFor more than 30 years, agronomists, soil scientists, consultants and farmers have recognized the potential for significant responses to applied sulfur fertilizer in northern and western Wisconsin on lighter textured, low organic matter soils that had not recently received manure (Rand et al., 1969; Hoefi and Walsh, 1975; Schulte, 1976; Peters and Kelling, 1987). More recently, crop consultants and others have reported seeing sulhr responses on soils or in locations where they typically were not... |
9. Varying Nitrogen and Seeding Rates of Corn Across Productivity Regions in FieldsA field study was conducted fiom 1999 to 2001 to determine the effects of variable seeding rates and variable nitrogen rates on corn (Zeu muys L.) in southern Ihois. In whole field experiments, variable seeding rates ranging fiom 18,000 to 38,000 seeds ac-' in 4.000 seed increments were planted in randomized strips (in a randomized complete block design) across the field that had soils with varying productivity based upon historical yield maps. From the yield data it was determined that the optimum... |
10. Using Historical Yield Patterns in Fields as a Management Tool to Variably Apply NitrgenIn whole field studies in southem Illinois a uniform rate of N application was compared with variably applied rates of N based upon historical crop yields for each field. The fields used were partitioned in "low". "medium", and "high" zones of productivity depending upon the normalized yield of the preceding 5 to 10 years of crops grown. Two formulas were used to variably apply nitrogen. One formula (VRN-One) calculated a N rate that favored more fertilizer in "high" productivity regions and less... |
11. Fertilizer Placement in Fall Strip TillageFall strip-tillage potentially provides an opportunity to increase conservation-till corn yields while sirnplifylng corn planters by minimizing the need for multiple coulters and application of relatively high rates of starter-band fertilizer associated with no-till. However. little is known about the relative efficiency of P and K application using fall strip-till systems co~npared to when starter-band applied in no-till systems. The objectives of the research reported in this study were to evaluate... |
12. Validating the Wisconsin P Index with Measured Runoff P Losses From Agricultural FieldsPhosphorus (P) indices have been developed by most states in the USA for use as planning tools to assess the risk of P loss and identify appropriate management alternatives to control these losses where needed. Little information is available on the relationshp between P index values and actual P runoff losses in the field. We compared annual P losses in runoff measured at 2 1 field or sub-watershed locations with Wisconsin P index values calculated for the same areas. The research sites included... |
13. An Environmental Assessment of Sensor-Based Variable-Rate Nitrogen Management in CornIn order to address the problem of nitrate contamination of surface and ground waters, various methods have been used to try to account for spatial variability of N within agricultural fields. One approach to account for this variability and thereby reduce nitrate pollution is in-season site- specific N application according to economic optimal N rate (EONR). Recently, active crop canopy sensors have been tested for mid-season, on-the-go N fertilizer application in corn. This 2004 and 2005 study... |
14. The Use of Organic Soil Amendments for Winter Wheat Production in KentuckyMost animal manures are land-applied in the fall and spring after crops have been harvested or prior to planting. Surface application of manures in the fall have more potential for nitrogen (N) loss when applied to fallow land compared to land cropped to winter wheat. This study was conducted to determine the N availability of fall applied organic fertilizers and resulting wheat grain yields compared to urea-N fertilizer. The effects of three organic fertilizer sources and rate on wheat yield and... |
15. Overview of Manure Handling on Steroid Movement in Agricultural Fields from Beef Cattle SystemsManure generated from concentrated animal feeding operations may serve as a source of steroids in surface water and potentially in groundwater. The objectives of this research were to determine the amount of steroids and metabolites in runoff from beef cattle production pens, and from runoff and leaching from crop production fields. Cattle were fed a synthetic progestagen, MGA or melengestrol acetate and treated with zeranol, trenbolone acetate, and estradiol implants, while a second group was not... |
16. Nitrogen Management of Temporary Waterlogged Soil to Improve Corn Production and Reduce Environmental N LossDuring the 2011 growing season excessive soil moisture in the Unites States accounted for at least 30% of the total crop loss to environmental stresses resulting in more than $3 billion dollars in insurance indemnities paid to farmers. The objectives of this study were to: (i) assess grain yield and N silage uptake for both rescue and non-rescue treatments of different enhanced efficiency products, (ii) determine soil N content among treatments throughout the growing season, and (iii) evaluate PCU... |
17. Evaluation of Crop Canopy Sensors as a Tool for Soybean Research and ProductionDetermining the variables that consistently increase yields in soybean  [Glycine max (L.) Merr.] continues to challenge researchers, agronomists and growers alike. Crop canopy sensors have emerged as a technology used in other cropping systems to monitor and manage agricultural inputs. The sensors measure reflectance in selected wavebands that are used to calculate vegetation indices that relate to unique leaf or canopy characteristics. The objectives of this study were to determine if a commercially... |
18. Nitrogen Contribution from Different Manure SourcesNitrogen fertilizer equivalencies (NFE) from manure are influenced by manure type, application method, crop selection, and environmental conditions. Much of the research to determine NFE of manure was conducted in tilled systems but many producers use no-tillage (NT) to reduce soil erosion and labor requirements. The objective of this study was to determine NFE for different manure types used in corn (Zea mays L.) cropping systems. Manures consisted of composted swine manure (CSM), poultry litter... |
19. Switchgrass Rhizobacterial Community Structure as a Function of Cultivar and Nitrogen Fertility at Two Sites in MinnesotaBiofuel production using native perennial grasses such as switchgrass (Panicum virgatum) has potential to reduce U.S. dependence on foreign oil and curtail greenhouse gas emissions. Switchgrass can also provide significant ecosystem services, such as nutrient loss reduction and carbon sequestration. Best management practices (BMPs) for switchgrass fertility are being established on a regional basis, yet little work has been done to examine the intersection of soil fertility with soil biology in switchgrass-for-biofuel... |
20. Soil Mineralogy and Potassium AvailabilityIn this talk, I will try to answer four questions. The outline below gives the overall framework for the presentation. 1. What are the mineral sources of potassium? Primary minerals crystallize from the magma. Those that contain K are: Feldspars (microcline and orthoclase) Micas (biotite and muscovite) Primary minerals weather decompose by several mechanisms. Chemical bonds are destabilized by acid attack. Al ions are complexed by organic... M.L. Thompson |
21. Enhanced Efficiency Phosphorus Application for a Corn-Soybean RotationPhosphorus (P) is an essential plant nutrient that is taken up by plants as inorganic ions (H 2PO4- and HPO 4 -2) found in soil solution. With higher fer tilizer costs, farmers are evaluating application rates and considering enhanced effi ciency phosphorus applications or treatments. AVAIL®(Specialty Fertilizer Products, Leawood, KS), NutriLife Max® (Advanced Microbial Solutions, Pilot Point, TX), and P ₂O ₅ Max (Rosen's Inc., Fairmont, MN) are three products that are intended to enhance the... |
22. Nutrient Management Studies in Bio-Fuel Cropping SystemsResearch was conducted to determine the effect of nutrient management practices on bio-fuel crop production, and to evaluate long term effects of bio-fuel crop production on selected chemical, physical and microbiologi cal properties. Experimental plots for research on bio-fuel crops production were established in 2008 at two sites in Missouri. The experimental design was an 8x3 factorial laid out in a sp lit plot design. The main plots were eight bio-fuel cropping systems including: 1) continuous... |
23. Nitrous Oxide Emissions in Claypan Soils Due to Fertilizer Source and Tillage/Fertilizer PlacementNitrogen fertilization for agricu ltural production is a major contri butor to increased soil nitrous oxide emissions. These emissi ons may contribute to global warming and ozone depletion. Nitrogen fertilizer source and placeme nt can influence soil nitrous oxide (N 2O) emissions by affecting the concentration of ammonium and nitrat e available for nitrification and denitrification throughout the growing season. The objectives of this research were to quantify the effect of tillage / fertilizer... |
24. What are the Benefits of Canopy Sensing for Variable-Rate Nitrogen Corn Fertilization?Canopy reflectance sensing for assessing crop N health has been proposed as a technology on which to base top-dress variable-rate N applicat ion. The objective of this research in Missouri was to evaluate the economic a nd environmental benefit of activ e-light crop-canopy reflectance sensors for corn N rate decisions. A total of 16 field-scale experiments were conducted over four seasons (2004-2007) in three major soil areas. Mu ltiple blocks of randomized N rate response plots traversed the length... |
25. Chloride Fertilization on Wheat, Corn, and Grain SorghumResearch in the Pacific Northwest and the Northern Great Plains has documented positive cereal grain responses to chloride (CI) fertilization. Field research was conducted in Kansas evaluating CI fertilization on winter wheat, corn, and grain sorghum. Chloride fertilization consistently and significantly increased plant CI concentrations in all crops. Chloride fertilization increased grain yields or one or more winter wheat cultivars at 3 of 4 sites. The most dramatic yield increases were at the... |
26. Cover Crops Influence Soil Health and Nutrient Cycling in a Multi-Location Study in South DakotaSoil without living roots potentially loses mobile nutrients and retains excess water. Unprotected soil degradation and erosion enable the loss of carbon and nutrient rich top soil. Cover crops provide armor for the soil protecting from carbon and nutrient loss. Cover crop blends may influence soil health parameters and nutrient cycling. This multi-locational study depicts the influence of cover crop species blends with varying grass and broadleaf concentrations on established soil-health indicators... D. Sanyal, J. Wolthuizen, D. Karki, J. Clark, A. Bly |
27. No-till and Cover Crops Influence Soil Health and Nitrogen Rate and Timing Recommendations: Early ResultsThe idea of improving soil health has become increasingly more talked about by researchers, agronomists, and farmers in the past five years. Management practices such as no- or reduced-tillage and planting cover crops are recommended to improve soil health because of their potential to improve organic matter and soil structure leading to a greater capacity to hold water and nutrients needed for plant growth. Research in South Dakota has been occurring these past two years to determine the influence... J.D. Clark, A. Bly, D. Karki, D. Sanyal, J. Wolthuizen, P. Kovacs |
28. Four R Nitrogen management for cotton. MU-FDRC research update.Cotton is a much different crop than corn. In addition to the dicot vs. monocot difference, cotton is a perennial plant cultivated as an annual crop. A cotton crop must be “encouraged” to produce fruit and hence lint in this production system. Input management, including nitrogen fertilizers, are central to modern cotton production. Adequate nitrogen must be available to a cotton crop during the critical flowering period. In Missouri this is from mid-May to... D. Dunn |
29. Does Starter Fertilizer Benefit Late Planted Corn?Starter fertilizers are used by producers to help overcome wet and cool soils often encountered with early planted corn. Early planted corn in no-tilled fields and limited drainage typically have the greatest chance of response from starter fertilizers. Starter fertilizers can range from a mixture of UAN, ammonium polyphosphate (APP), and other fertilizers to low salt (LS) formulations containing N, P, K and various micronutrients. Some that promote LS starter fertilizer products claim that UAN... E. Ritchey, H. York |
30. Nitrogen Source and Timing Effects on CornThe 4R’s of nutrient management call for the right source, applied at right time, at the right rate at the right placement. Producers in South Dakota ask when the correct time to apply nitrogen fertilizers. Mean annual precipitation in the major South Dakota corn growing areas ranges from 16 to 26 inches. This is a relatively dry climate compared to other major corn growing regions and the effect of nitrogen timing might not be as important. Therefore, a research question that challenges... A. Bly, S. Berg, D. Karki |
31. Soil Phosphorus Fractions and Legacy after Long-term Fertilizer Placement in a Corn-Soybean RotationPhosphorus (P) fertilizer placement can affect plant P uptake during the growing season, however, the long-term interaction of placement and plant root P uptake can also affect soil P pools. The objective of this study was to evaluate the influence of long-term P fertilizer placement on soil P pools (labile, moderately labile and non-labile) and legacy soil P accumulation under a corn (Zea mays) -soybean (Glycine max (L.) Merr.) rotation. A field study was conducted for ten years from 2006-... M. Coelho, D. Ruiz diaz, G. Hettiarachchi, F. Hansel |
32. Assessment of Plant Nitrogen Uptake with Late Fertilizer Applications in CornPrevious research in Kansas and other regions has shown that split applications of N fertilizer with early side-dress can increase yield compared to applications at planting in some site years. Split applications are typically done using the traditional side dress at the V6-V8 growth stage. However, late N applications (late-vegetative or early reproductive stage) is generating interest as one alternative to improve nitrogen use efficiency and possibly increase yields,... D. Diaz, A. Stammer, F. Hansel |
33. Not All Litter is Created Equal: Differences in Nitrogen Mineralization Among Broiler Litter TypesOver three fourths of U.S. broiler chicken production is located in the Southeast and generates a substantial amount of broiler litter (BL). Broiler litter is a mixture of bedding material and manure that can be a valuable nutrient source for row crop production when properly used. New technologies provide farmers with the opportunity to use a combination of BL and inorganic fertilizers with minimal environmental impact. The first part of the project evaluated integrated N management systems that... L. Fitzgerald, E. Ritchey, J. Mcgrath, J. Shockley, H. Poffenbarger |
34. Performance of Grain Oats at Different Nitrogen Regimes when Grown with and without Plant Growth Regulator (PGR)Among small grains grown in the South Dakota (SD), oat is considered the most susceptible to lodging which can result to significant yield loss due to harvest difficulty. Although current South Dakota State University (updated 2005) recommends 1.3 pounds nitrate N per bushel of oats (minus soil test N and legume credit), producers have been using lesser than the SD recommended rate to avoid lodging. This study was initiated in 2016- i) to evaluate the response of oat grain yield at various nitrogen... D. Karki, A. Bly |
35. Grid Soil Sample Interpolation Using Geographicaly Weighted Regression and Random ForestSoil sampling is useful in agriculture for setting fertilizer application rates. High density soil samples can also be used for variable rate seeding and other precision agriculture applications. Half-acre grid soil samples were collected from 6 soybean fields, and phosphorous (P), potassium (K), and organic matter (OM) were measured. Each soil parameter was interpolated for each field, with terrain attributes as covariates, using two different methods: geographically weighted regression (GWR)... E. Matcham, S. Subburayalu, J. Fulton, E. Hawkins, P. Paul, L. Lindsey |
36. Sulfur Fertility for Kentucky Agriculture: An UpdateSulfur (S) is an essential secondary nutrient for plant growth and is involved with the synthesis of chlorophyll, hormones, and a structural component of proteins. The need for supplemental S fertilizer in Kentucky has been questioned for many years due to lower atmospheric S deposition, fewer fertilizer impurities, soil test laboratory recommendations, and greater crop yields, but field research has not supported this concern. Recent tissue surveys in wheat and alfalfa across Kentucky... E. Ritchey, J. Gray |
37. An Integrated Approach to Understanding Poultry Litter Use in Corn-Soybean Production SystemsThe majority of poultry litter (PL) in Kentucky is generated in the western third of the state, the same area that produces approximately 80% of corn, soybean, and wheat. This PL is applied to row crop fields as a nutrient source. Producers and commodity board representatives were concerned with reported nutrient availability coefficients, nutrient value, and long-term use of PL. Four field sites in a NT corn-soybean rotation were identified in the fall of 2012 with low to medium soil test values... E. Ritchey, E. Haramoto, C. Bradley |
38. Tillage, Crop Rotation, and Cover Crop Impact on Corn Nitrogen Requirements in Southeastern South DakotaNitrogen is the lifeline of corn production. There is uncertainty whether nitrogen (N) requirements are the same for corn raised under long term no-till versus conventional till production systems. The objective of this study was to evaluate N fertilizer requirements for long term no-till soils in southeastern South Dakota, while considering effects from cover crops and crop rotation. This was a two year study at the SDSU Southeast Research Farm near Beresford, SD on long term no-till plots established... S. Berg, P. Sexton, R. Gelderman, A. Bly, C. Derdall |
39. Potassium Effects on Yield, Grain Quality, Lodging, and Stalk Strength in RiceMissouri has a long history of rice production, going back to 1910 when the crop was first grown in the northeast region of the state. From this 40-acre start, rice acreage has increased steadily over the years to over 180,000 acres currently. The statewide average yield was 110 bu/A in 1997 and increased to over 156 bu/A in 2015. Traditionally, nitrogen (N) management has been given top priority by farmers. But with increased yields and rotations with soybeans, K fertility is increasingly being... D. Dunn, G. Stevens |
40. Phosphorus Distribution After Long-Term P Fertilizer Placement Under Strip-TillageLong-term phosphorus fertilizer placement under strip-tillage tillage can affect the vertical and horizontal distribution of soil test P (STP). The objective of this study was to evaluate the effect of P fertilizer placement on STP distribution under strip-till. A study was established in Scandia, Kansas in 2006 under a corn- soybean rotation. Treatments included a (1) control (No P); and P applied at 80 lb P2O5 ac-1 as (2) broadcast, (3) deep band, (4) broadcast with starter 2x2, and... C. Edwards, D. Ruiz diaz |
41. N-Fertilizer Recovery Efficiency by Corn Using Controlled Release UreaLimited research has been conducted on the use of 15N-labeled controlled release urea fertilizers under field conditions for corn production. The objectives of this study were to: 1) evaluate the fate of N derived from a blend of two enhanced efficiency N fertilizers in corn plants throughout the growing season; and 2) to determine the N recovery efficiency of the two N sources from a blended application. A field study was conducted during the 2015-2016 growing season at Iracemápolis,... H. Gonzalez, D. Ruiz diaz, C. Filho, P. Trivelin |
42. Soybean Yield Response to P Fertilizer Placement as Affected by Soil Parameters: A ReviewIn the last decades, several studies were conducted to evaluate more efficient P fertilizer management with emphasis on placement. Many of these studies report contrasting results, suggesting that a general recommendation may not be appropriate and specific factors of soils, crops, and weather should be considered. A literature search was completed using Google Scholar, and published papers that met our selection criteria included 62 experiments, with 95 site-years. Approximately 9.8% of the studies... F. Hansel, D. Ruiz diaz, L. Rosso |
43. Effects of Applied Soil Micronutrients on Corn and Soybean Yields in Eastern South Dakota EnvironmentsMicronutrients although taken up by plants in small quantities, their deficiencies can have significant detrimental effects on grain yield. As growers aim for maximum corn and soybean yields, availability of micronutrients in agricultural market both as individual source or combined with other secondary nutrients have also increased. However, effects of micronutrients on corn and soybean grain yields are not well documented for South Dakota (SD) soils, and growers seem to be concerned if application... D. Karki, A. Bly, S. Berg |
44. Fall Nitrogen for Winter Wheat Production?Fall nitrogen (N) applications are typically not recommended in Kentucky unless previous corn yields exceed 30 bu/A more than expected or when wheat is planted later than optimal in combination with a wet fall. In 2016, much of Kentucky experienced this combination of yield and environmental conditions. A study was initiated to test the need for fall applied N and how much fall N may be needed. Wheat was planted at recommended (normal) dates and then at dates that would be considered later than... E. Ritchey, J. Grove |
45. South Dakota Producers Use of Soil Testing to Make Soil Fertility DecisionsSoil fertility guidelines in South Dakota are primarily based on soil testing results. There are several possible soil sampling procedures regarding timing, frequency, and type of soil sampling that can be followed by producers. Survey information collected from South Dakota producers can inform us what soil sampling procedures they are commonly using. We distributed a survey to 3,000 South Dakota producers based on crop reporting district, crops grown, and farm size. We reminded producers three... |
46. Reevaluating Potassium Recommendations for Soybean Production in KentuckyFertility recommendations from land grant universities are typically lower than private soil test laboratories and lead producers to question the adequacy of current recommendations. Further, soil samples analyzed at UK Regulatory Services Soil Testing Laboratory indicate that average state-wide soil test potassium (K) levels are declining approximately 1 lb K/A/year. The reason for this decline is not known, but some suspect it might be due to increased crop yields while maintaining historical... E. Ritchey, J.H. Grove, J.M. Mcgrath |
47. Applying N to legume-containing summer annual forage mixturesSummer annual forages are costly to implement but can provide quality grazing when cool-season perennial forages are less productive. Increasing botanical diversity may increase system productivity, thereby improving economic efficiency. However, there is debate as to whether annual legumes supply associated grasses with fixed N, leading to uncertainty regarding N application rates to legume containing summer annual forage mixtures. This experiment supplied three summer annual forage treatments... K. Mercier, C. Teutsch, S. Smith, E. Ritchey, K. Burdine, E. Vanzant |
48. Seed Germination as Influenced by Fertilizer Type, Seed Coating, and Duration of StorageOverseeding forages into existing pastures and hayfields helps maintain dense stands and sustain productivity. Fertilizer applications to stimulate early spring growth provides an opportunity to blend forage seed with fertilizer. Additionally, seed treatments are often used to improve the ability to handle small seeds and to improve percent germination over raw or uncoated seed. Little is known about how seed coating, fertilizer type or duration of exposure to fertilizer will influence seed germination.... E. Ritchey, C. Teutsch |
49. Effect of Liquid Calcium as a Liming Agent in SoilMaintaining proper soil pH is the foundation of a soil fertility program and influences plant productivity, nutrient availability, and herbicide activity. This study was conducted to determine the effectiveness of liquid calcium compared to known liming agents to raise the pH of soil. Test plots that compare liquid calcium to proven liming agents were conducted in 17 counties across the state of Kentucky on cool season annual grass pastures. Two experimental protocols were developed... B. Setchell, E. Ritchey |
50. N, S and Micronutrient (B + Zn) Interactions in Soft Red Winter Wheat NutritionThis work is intended to answer certain questions that result from the implementation of a multi-element wheat nutrition program. Nitrogen rate is a fundamental driver of wheat yield and quality. However, the impact/value of S or the micronutrients, which are likely components of a more integrated wheat nutrient management program, is not clear.The main study design included 4 rates of N (40, 80, 120 and 160 lb N/acre), 2 rates of S (0 and 10 lb S/acre), and 2 rates of the micronutrient ‘package’... J. Grove, E. Ritchey, J. Shockley |
51. Ag Economy and Policy Outlook for 2024We will explore the factors currently shaping the ag economy and the various sectors that drive economic growth in the sector. We will investigate the connections among feed, fuel, and export markets and examine potential changes to federal agricultural policy (i.e., the Farm Bill). We will discuss the potential for agricultural profitability over the next few years and outline the challenges to reaching robust economic gains. ... C. Hart |
52. Impact of Cover Crop Composition on Nitrogen Application Rates and the Subsequent Yields of Corn and SoybeanInterseeding cover crops presents a promising strategy for enhancing the sustainability of agricultural systems. Nevertheless, the practice of interseeding cover crops introduces a dynamic element to nitrogen (N) cycling, potentially altering both the quantity and timing of N release through decomposition (mineralization). This variability in N availability may, in turn, influence the optimal nitrogen fertilizer requirements to maximize corn grain yield. However, long-term studies are essential... J.D. Clark , P. Kovacs, P. Sexton, S. Osborne, S. Kodali |
53. The Alfalfa Yield Plateau: is Soil Fertility the Cause?Alfalfa is a perennial forage legume known for its ability to produce high quality hay, earning it the title the “Queen of Forages.” It is produced across the United States as feed for the beef, dairy, and equine industries. During the 1950s, alfalfa yields rose exponentially due to advances in technologies such as improved varieties, synthetic fertilizers, and pesticides. However, yields plateaued at approximately 3.3 tons per acre in the 1980s for reasons not fully understood and... W. Fleming, E. Ritchey, C. Teutsch, J. Grove |
54. Effect of Phosphorus and Potassium Application on the Growth and Yield of a 14 Year Old Miscanthus X Giganteus StandMiscanthus x gigantues (miscanthus) is a perennial C4 grass grown for renewable bioenergy and bioproducts. Despite its known low nutrient requirements, the specific fertilization needs of miscanthus remain poorly constrained, especially for older stands. This study aims to guide nutrient management practices for miscanthus by determining the demand for phosphorus (P) and potassium (K) fertilization and identifying the soil testing values at which these nutrients optimize yields. To address this... A. Larson, E. Heaton, N. Boersma, J. Studt, S. Emran, M. Mcdaniel, A. Vanloocke |
55. Corn Response to Sulfur Fertilization in Central Iowa SoilsReductions in atmospheric sulfur (S) deposition and increased S removal through continuous cropping have led to S fertilizer responses in many crops. Responses to S fertilization by corn (Zea mays L.), however, have been inconsistent across the upper Midwest. Our objectives with this field study were to: (i) compare S sources for corn vegetative growth and grain yield; (ii) evaluate soil extractable S and S tissue concentrations at different growth stages as S diagnostic tools;... J. Kovar, C. Crespo, C. Hart, R. Roth, P. O'brien, S. Ruis |
56. Updating Nitrogen, Phosphate and Potash Rate Recommendations (AGR-1) for Kentucky Grain GrowersFor UK soil test lab users, soil test phosphorus (P) and potassium (K) have been slowly declining for several decades, suggesting recommended ‘maintenance’ rates (initiated in 1992) were insufficient. Adjusting for modern grain P and K concentrations and increasing yield-driven nutrient removal, we raised corn, soybean and wheat maintenance rates by 10 to 20 lb P2O5 and 10 to 30 lb K2O per acre, depending on the individual crop. Corn nitrogen (N) rate recommendations had not been... J. Grove, E. Ritchey |