Proceedings
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1. Adapt-N: A Computational Tool for Precise N Management in CornCurrent approaches to estimation of optimum N fertilizer rates are based on mass balances, average expected economic return based on field experiments, soil N tests, an d crop leaf or canopy sensing. However, denitrification and leaching losses of nitrogen may occur from dynamic and complex interactions among weather, soil hydrology, crop water and N uptake, and management practices , and result in high variability in annual crop N needs in maize ( Zea mays L.) production. W eather impacts the ... |
2. Assessing Nitrogen Management and Claypan Soil Variability Effects on Switchgrass using Reflectance SensingThe topsoil depth or depth to the claypan (DTC) can be highly variable across the landscape for some Midwest soils. This makes managing crops on these soils difficult because their productivity can be highly variable. In some ar eas of the landscape there can be no topsoil and leave the claypan exposed (e.g., side-slope) while in other areas it can be buried (e.g., toe-slope) (Kitchen et al., 1999). Due to the high variability of theses soils, switchgrass (Panicum virgatum L.) is a potential pro... |
3. Biochar: Waste, or Product?Nutrient losses following summer and fall manure applications result in economic and water quality problems. We tested the potential of biochar (BC) and ammonium thiosulphate (ATS) as manure additives to retain nutrients by reduci ng nitrate pool size and runoff of N and P. To determine appropriate rates to use in field expe riments, the compounds were initially added at different rates to liquid swine manure (LSM) then the slurry mixed with soil and incubated. The selected rates, based on N tra... |
4. Building a Corn Nitrogen Rate Database for Minnesota's Irrigated Sandy SoilsA study was conducted to determine the optimum N rate to apply for corn grown on irrigated sandy soils in Minnesota. Sandy soils in Minnesota vary in the texture of the surface fron silt loam to sand. Since 2006, 11 sites had 8 to 9 N fertikizer rates applied. The optimum N rate for the sandy sites with a silt loam surface texture ranged from 168 kg N/ha to 200 kg N/ha while the sandy surfaced soils optimum N rate ranged from 250 kg Nha to 280 kg N/ha. The silt loam surface soil sites optimum N ... |
5. Can Unmanned Aerial System-Mounted Passive Sensors Be Used To Recommend Sidedress Nitrogen Rates In Corn? A Comparison Between Active and Passive SensorsThe objectives of this research were to (i) assess the correlation between active and passive crop canopy sensors’ vegetation indices at different corn growth stages, (ii) assess sidedress variable rate nitrogen (N) recommendation accuracy of active and passive sensors compared to the agronomic optimum N rate (AONR) and (iii) assess sidedress VR N rate recommendation correlation between active and passive sensors. Two experiments were conducted, one near Central City, Nebraska on a Novi... L. Bastos, R. Ferguson |
6. Chemistry of Soil Phosphorus - Agronomic and Environmental ImplicationsTo be available for uptake by crop plants or to stimulate algal growth in a eutrophic environment, P must in a dissolved form. Therefore, in the absence of soil erosion, chemical processes that can transfer phosphate ions from the soil solution to the solid phase can limit P bioavailability and mobility. These processes include exchange, adsorption, and precipitation reactions. This presentation focuses on how local fluctuations in soil water content, solution pH, redox potential, and dissolv... M. Thompson |
7. Comparative N and Dry Matter Dynamics in Corn Ears, Stems, and Leaves During the Critical Period After Early and Late-split Sidedress NThere is currently great interest in the possible agronomic and environmental benefits of split N applications that include a late vegetative sidedress timing. The objective of this study was to determine the impact of N rate and timing of N application on the accumulation of N and dry matter in the ears, stems, and leaves of corn during the critical period (encompassing the period two weeks before to two weeks after silking) in order to understand the differing sensitivity to N stress in the... S. Mueller, T. Vyn |
8. Corn Nitrogen Calibration in South DakotaSouth Dakota (SD) corn nitrogen (N) rate recommendations were last established in 1991 and based on the coefficient of 1.2 lbs N/bu of the yield goal. The South Dakota corn N rate calculator subtracts the pre-plant soil test NO3-N (0-2ft) and legume credits and adds 30 lbs N/a for recently established no-till. Much improved corn genetics, shifting farming practices, and climate changes warrant re-calibration of corn N rate recommendations. During 2013-2105, N rate studies were conducted at 20... A. Bly, S. Berg |
9. Corn Plant Uniformity Following Shallow NH3 Placement in Precision-Guided, Pre-Plant Nitrogen ApplicationsCorn (Zea mays L.) production relies extensively on different types of N fertilizers, and anhydrous ammonia (NH 3) continues to be a dominant N s ource in much of the Corn Belt. Timing and placement of NH 3 fertilizer can affect plant-to-plant uniformity and yield of corn, and especially so when high N rates are applied and there is little time between spring pre-plant NH 3 application and planting. The effects of shallow pre-plant NH3 placement on corn plant-to- plant uniformity were investig ... |
10. Corn Residue Harvesting Effects on Yield Response to N FertilizationProducers have many choices of diverse tillage practices for their corn (Zea mays L.) production systems. However, no-till has become an important soil management practice to help reduce water and wind erosion, as well as nutrient runoff, while conserving soil moisture for crop use. No-till systems also help farmers by saving labor and time, as well as reducing farm costs due to less equipment and fuel consumption. Nevertheless, no-till production is typically more successful and has higher crop... |
11. Do Soil Tests Predict Yield Response to Phosphorus in Modern Corn and Soybean Production?Modern corn (Zea mays L.) and soybean [Glycine max (L.) Merr.] production systems produce higher yields, and consequently, may remove more nutrients than fertilizer rates based upon existing soil test recommendations for these yields. With greater emphasis on soil test levels for nutrient stewardship strategies, soil tests need to also predict critical levels in which fertilized nutrient responses are likely. Current soil test recommendations for Illinois have negl... T. Beyrer, F. Below |
12. Effect of Late-Applied N on Corn Dry Matter, N Content, and YieldNitrogen management of corn (Zea mays L.) may be improved by delaying N application until just prior to the rapid growth phase (approximately V6-V8). This timing is commonly referred to as 'sidedress'.� Some farmers do not sidedress because they are concerned inclement weather may delay N application beyond V8, requiring high clearance equipment to apply N and possibly reducing grain yield. However, few studies have investigated the effects of late-applied N in rain-fed production environment... |
13. 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 appl... D. Karki, A. Bly, S. Berg |
14. 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 ... |
15. Evaluation of Algorithm Thresholds for Crop Canopy Sensor-Based In-Season Nitrogen Application in CornNitrogen fertilizer is frequently the most lim iting nutrient in corn production. Typically most nitrogen is applied before plan ting. Since nitrogen can leave th e soil system fairly easily, the result can be an inefficient use of nitrogen fe rtilizer. Previous research has shown increased efficiency with no reduction in yield by applying nitrogen later in the season when the crop is actively growing, with rates regul ated spatially through the use of active crop canopy sensors. This study eva... |
16. Evaluation of Four Iron Sources for the Control of Iron Deficiency Chlorosis in SoybeanIron deficiency chlorosis (IDC) is a destructive disorder of soybeans grown on calcareous soils in the North Central region. Certain chelates are effective at preventing IDC, but the quality of commercial-grade materials varies. The objective of this greenhouse study was to compare the ability of four commercial iron fertilizers to prevent IDC in soybeans. The four sources were a high-quality FeEDDHA product (FeEDDHA-1), an FeEDDHA product of lower quality (FeEDDHA-2), FeEDDHSA, and FeHBED. T... H. Ohm, R. Goos |
17. Evaluation of Novel Soybean Inputs to Enhance YieldThe U.S. Average soybean yield was 43.5 bushes/acre in 2010 (www.nass.usda.gov), with reports of much higher yields in some areas. With large yield differences among years and locations, as well as some high-profile marketing and publicity campaigns promoting 'high yield' management, producers are interested in any inputs or management practices that might improve yields. High soybean prices at present and interest in finding ways to increase yield have led to emergence of a number of new produc... |
18. Evaluation of Polyhalite as a Source of Potassium and Sulfur for a Corn-Soybean Rotation in MinnesotaPolyhalite contains K, S, Mg, and Ca which could be used as a source of nutrients for crops in Minnesota. The objective of this research was to determine if polyhalite can utilized within for a two-year corn (Zea mays L.)-soybean [Glycine max (L.) Merr.] rotation. Field studies were established at two locations in Minnesota with the soil test K of <120 ppm (0-6 inch sample extracted with 1M NH4OAC) and where a response to S was expected. Treatments were polyhali... A. Sutradhar, D. Kaiser, C. Rosen |
19. 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 th... E. Ritchey, J. Grove |
20. Identification of Reasons for High Temporal Soil-Test Potassium VariationExtensive research has focused on potassium (K) fertlization and soil K testing during several decades in the Corn Belt. IN Iowa, more t han 200 conventional or on-farm strip trials were conducted since the iddle 1990s until the early 2000s. Results of this research were used to update Iowa State University (ISU) K recommendations in 1999 and in 2002. In spite of increasd knowledge about soil-test K calibration, K fertilizer placement meethods, and needed K fertilizer rates, this research demons... |
21. Impact of Nitrogen Application Timing on Corn ProductionWater quality issues have renewed interest in timing of nitrogen (N) application as a means to improve use efficiency in corn and reduce losses. Improved economic return is also desired as N fertilization is one of the most costly inputs to corn production. Time of fertilizer application is a component of the site-specific 4R nutrient management stewardship programs. In Iowa, the Nutrient Reduction Strategy has a 7% (37% std. dev.) nitrate-N reduction with a 0% (3% std. dev.) corn yield chang... J. Sawyer, D. Barker, J. Lundvall |
22. In-Season Soil Nitrogen as a Predictor of Corn Grain YieldCorn (Zea mays L.) grain yield is closely linked to plant available soil nitrogen (N). Our objectives were to (i) examine the influence of N rate, source, and time of application on N use efficiency with relation to grain yield and total plant N uptake, and (ii) evaluate in-season soil N testing as a tool to determine N rate needs and predict grain yield. During the 2014-2015 growing seasons, 12 fields across Minnesota varying in soil and climate conditions received 1) pre-plant urea (0 to 20... J. Spackman, F. Fernandez |
23. Independence of Crop Yield and Nitrogen Rate Across SitesHistorically soil fertility specialists in the North Central States of the USA have constructed nitrogen (N) rate recommendations based on ‘yield goals’ or ‘expected yield’. Within the past ten years, there has been a general realization by soil fertility researchers that within a site or field there is a relationship between N rate and yield; however, because of soil and weather differences between sites there is no relationship in N rate studies with a large number o... D. Franzen, L. Sharma, H. Bu, E. Schultz, J. Breker, A. Denton |
24. Influence of Source and Particle Size on Agricultural Limestone Efficiency at Increasing Soil pHExcessive soil acidity is known to have potential negative impacts on crop production. The chemical and physical characteristics of a liming material determine its capacity to neutralize soil acidity. The calcium carbonate (CaCO3) equivalent (CCE) and estimates of particle size impact on the efficiency at increase soil pH are considered when assessing a material’s liming value. The reaction of limestone particles within the soil depends largely on the soil pH and the material surface ar... J. Jones, A. Mallarino |
25. iPhone Apps: Corn Nitrogen Fertilizer Rate Calculator and Nitrogen Fertilizer Price Comparison CalculatorAs communications technology advances, there is a need for Extension to deliver information and decision- making tools that leverage these new technologies to engage existing and new clientele groups in new wa ys. Smart technologies allow ac cess to pertinent information on-the- go and out in the field, right when it's needed. ... |
26. Irigated Soybean Response to Nitroen Applied During Early Pod FormationHigh yield soybean ( Glycine max L.) has a high rate of N uptake during grain fill with maybe 2/3 of the N derived from the atmosphere. The rema ining needs to come from the soil. Previous research has found that the probability of response to N applied at early pod development (R3) for yield trials, including 44 with mean yield >60 bu/A, we re conducted in Nebraska to determine effect on soybean yield of applying N and S to the soil at R3. With 27 lb/A N applied and >60 bu/A yield, mean yield ... |
27. Managing Riparian Buffers to Improve Soil Structural PropertiesFifty-five percent of Kentucky's stream impairments have been attributed to agriculture. Riparian buffer management may improve buffer effectiveness and reduce agricultural contaminants impairing water quality. Three mowing regimes and one native grass establishment regime were imposed in the riparian buffer zone surrounding a tributary of Cane Run Creek in Fayette County KY. Treatment plots measured 10m x 15m, with 10 replications of each treatment. One year after treatment, root biomass, soil ... |
28. Managing Urea Fertilizer for Optimal N Use and Productivity of CornCorn (Zea mays L.) yield is usually limited by nitrogen (N) availability more than any other nutrient in agricultural soils. Urea is the primary source of inorganic nitrogen fertilizer used worldwide, either as a crystalline solid containing 46% N, or a urea-ammonium nitrate solution (UAN, 28-32%). A major caveat, however, to urea as an N fertilizer is its susceptibility to loss through volatilization when applied to the soil surface. Many products are marketed as nitrogen stabi... B. Bernhard, F. Below |
29. Manitoba Corn Meets 4-R Nitrogen Management (Year 2): Effects on Crop Performance and the EnvironmentReplicated corn trials to evaluate previous research on fertilizer technologies were conducted in 2015 under farm conditions at three sites Manitoba as well as in Quebec. Sites were located northwest of Elm Creek, MB on a loamy fine sand, near Carman, MB on a loamy very fine sand and at Culross, MB (southeast of Elm Creek) on a Red River clay. Treatments in the Manitoba trials included: a zero N Check; three rates of urea/ESN (50% each by weight) broadcast/incorporated prior to plan... C. Cavers, S. Sager, G. Parent |
30. Micronutrients as Starter and Foliar Application for Corn and SoybeanCorn and soybean production under high yield environments can benefit from the combined use of starter and foliar fertilization, including macro and micronutrients. The objective of this study was to evaluate corn and soybean response to starter fertilizers in combination with foliar application of macro and micronutrients to maximize yield s. Experiments were conducted in 2010 and 2011 at two locations for corn and soybean under irrigation. Starter and foliar fertilizer treatments were applied ... |
31. Mine the Data Not the Soil: Big Data Considerations for Soil FertilityFarm data has become a current topic in agriculture as well as other industries and is known as ‘big data’. Debate regarding the ownership of the data and who should receive value from the use of that data are hotly debated. This paper dispels many of the myths of big data in agriculture and offers insights into best management practices with respect to using data isolated to a given farm as well as within a larger community. A substantial portion of this paper was adapted from Gr... T. Griffin |
32. Mitigating Phosphorus Movement from Agricultural FieldsAgriculture is often cited as the primary factor for the high P loads polluting Lake Erie and Ohio�۪s watersheds, but the contributions of agriculture as a system, a combination of tillage, best management practice (BMP) and fertilizer source rather than an industry is unknown. This study supplied either commercial fertilizer or poultry litter to tilled or no-till production systems with their corresponding BMPs of incorporation and cover crops, respectively, to determine the P lost via surf... |
33. 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 Iracemápo... H. Gonzalez, D. Ruiz diaz, C. Filho, P. Trivelin |
34. Nitrate-N Loss Reduction: Scale of In-Field and Edge-of-Field Practice Implementation to Reach Water Quality GoalsStates in the Mississippi River Basin have developed state level nutrient reduction strategies in response to the 2008 Hypoxia Action Plan. The Iowa Nutrient Reduction Strategy was released in 2013 and the Nonpoint Source Nutrient Reduction Strategy Science Assessment reviews potential practice performance in reducing downstream nutrient loss and the scale of implementation that would be necessary to reach the Hypoxia Action Plan goal of a 45% reduction in riverine Nitrogen and Phosphorus. To... M. Helmers |
35. Nitrogen Fertilizer Additives, Which Ones Work?Nitrogen fertilizer additives were evaluated in nine different studies. In the first study, Nutrisphere had no effect on urea hydrolysis when applied with a urea solution. In a second study, Nutrisphere had no effect on nitrification when applied with a urea solution. In a third study with urea granules, Nutrisphere had little effect on ammonia volatilization. In a fourth study with urea granules, Nutrisphere had no effect on nitrification. In a fifth study, Nutrisphere was found to be less effe... |
36. Nitrogen Fertilizer Management for Wheat Under Dual Purpose Grazing and Grain ProductionDual purpose winter wheat is a common system used in many regions of the Southern Great Plains. The objective of this study was to i.) evaluate the interaction of wheat grazing management and soil and fertilizer nitrogen requirements with emphasis on dual purpose wheat. This study was established at three locations during the 2015-2016 growing season. Experimental design was a randomized split block design with 16 treatments including simulated grazing and grain only treatments and varying ra... T. Gardner, D. Ruiz diaz, C. Edwards |
37. Nitrogen Fertilizer on Soybeans: Are We Making Progress?The recent drop in the price of soybeans has dampened enthusiasm for applying inputs of uncertain value to crops, but application of fertilizer N during the season is often reported by soybean yield contest winners as a way to increase yields, and some producers have adopted this as a practice. As soybean yields have increased, the amount of N required by the crop has increased. Soybean seed with 36 percent protein is about 5.75% N, and a bushel of soybean grain contains about 3 lb.... E. Nafziger, J. Vonk |
38. Nitrogen Management: Unraveling the Effect of Timing and FormImprovement of nitrogen use efficiency by co rn production would decrease the potential for nitrogen loss into the environment. A study ha s been conducted in Ames, Iowa on 16 different forms and rates of nitrogen in both a continuous corn and corn-soybean production systems. There were differences among treatments; howeve r, the most consistent treatment was the SuperU applied as a 150 lb A -1 preplant or as 50 lb A-1 preplant and 100 lb A-1 sidedress and UAN with Agrotain adde d to both the 5... |
39. Nutrient Deficiency Diagnostic Training with Field and Hydroponically Grown CropsThe Manitoba Crop Diagnostic School was initiated in 1995 and annually provides training for 350 - 400 field agronomists over a two week period in mid July. Symptons of nutrient deficiencies, other than Nitrogen (N), have proven difficult to demonstrate on the fertile high organic matter loam texturd soiles of the Carman Researh Station. The following techniques have been developed to demonstrate many of the macro and micronutient deficiencies which may occur in prairie crops.... |
40. Nutrient Management Practices for Water QualityField to Market®: The Alliance for Sustainable Agriculture Field to Market® is a diverse alliance working to create opportunities across the agricultural supply chain for continuous improvements in productivity, environmental quality, and human well-being. The group provides collaborative leadership that is engaged in industry-wide dialogue, grounded in science, and open to the full range of technology choices. ... A. Herges |
41. 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) continu... |
42. Phosphorus and Potassium Removal and Leaching from Residue in Corn and SoybeanResearch is continually being conducted to adjust and update recomm endations for phosphorus (P) and potassium (K), and to be tter understand relationships betw een nutrient application, grain yield, nutrient removal with harvest, and soil-test values. Studies in Iowa and other states of the north central region have been used to develop guidelines about P and K removal rates in corn and soybean for use together with soil testing information to manage P and K. There is very large temporal varia... |
43. Phosphorus and Potassium Response In No-Till Corn and Soybean ProductionCurrent UWEX fertilizer recommendations and plant analysis interpretation guidelines were developed prior to the release of GMO corn. There is some concern amongst University soil fertility specialists and industry agronomists that corn and soybean response to P and K fertilizer applications may be different with modern corn hybrids and soybean varieties. In addition, in the UW recommendation system, an estimate of the amount of nutrients removed in the harvested portion of the crop is used t... C. Laboski, T. Andraski |
44. 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, a... C. Edwards, D. Ruiz diaz |
45. Post-Harvest Soil Nitrate Following Corn Production in Eight Midwestern StatesApplying nitrogen (N) at economically optimal rates (EONR) and at times of rapid crop uptake are practices that are thought to minimize the amount of residual soil nitrate (RSN) in the profile that may be susceptible to loss. The objective of this study was to evaluate the effects of rate (0 to 280 lb N/a in 40 lb increments) and timing (pre-plant (PP) or PP plus V9 sidedress (PP+SD)) of N application on corn grain yield and RSN in the top 3 feet of soil relative to the calculated EONR. Thirt... C. Bandura, C. Laboski, J. Camberato, P. Carter, R. Ferguson, F. Fernandez, D. Franzen, N. Kitchen, E. Nafziger, J. Sawyer, J. Shanahan |
46. 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 be... D. Dunn, G. Stevens |
47. Potassium Recalibration for Corn in North Dakota and Sampling TimePotassium (K) fertilizer recommendations for corn (Zea mays, L.) are commonly guided by yield response calibrations to soil K levels; however, sample drying and time of soil sampling have been shown to affect the amount of extractable K. Potassium rate trials were established at 13 locations in southeastern North Dakota during 2015 with objectives to evaluate soil K testing methods and their relationship with corn yield response to K fertilization and to assess temporal soil K variat... J. Breker, D. Franzen |
48. Prediction of Corn and Soybean Grain Yield Response to P in Minnesota Using the Haney H3A and Mehlich-III TestsMinnesota soils are highly variable in P availability due to the wide range of chemical properties. Currently, two soil tests are used to measure soil P in Minnesota, the Bray-P1 for pH<7.4 and the Olsen P for pH>7.4. The purpose of this study was to correlate crop response in corn and soybean rotations to the Bray-P1, Olsen, Mehlich-III, and Haney H3A extractions and to determine critical concentrations for each extraction method. Soil P tests were also correlated with one another to d... D. Kaiser, L. Leverich, J. Vetsch, J. Strock |
49. Project Sense: Sensors for the Efficient Use of Nitrogen and Stewardship of the Environment. An On-Farm Research Effort to Increase Adoption of Sensor Based N ManagementLow nitrogen use efficiency (NUE) has been attributed to several factors including asynchrony between nitrogen (N) fertilizer application, crop demand, and spatial variability (Shanahan et al., 2008). Sidedress applied N synchronizes crop uptake demand for N, but does not address the spatial and temporal variability that exists in a field year to year. Active crop canopy sensors provide an ability to monitor and respond to spatial and temporal N variability for a given field. A three-year pro... B. Krienke, R. Ferguson, J. Luck, L. Thompson, J. Parrish, N. Mueller, T. Mieno, J. Crowther, T. Shaver, T. Ingram, D. Krull, K. Glewen |
50. Relationship between Nitrogen Rate and Weed Removal Timing on Corn YieldWeeds actively compete for nitrogen in corn grain production systems. Field studies were conducted in 2009 and 2010 at the Michigan State University Crop and Soil s Research Farm in East Lansing , MI to evaluate the effect of N application rate and weed removal timing on grain yield . Treatments included four preplant incorporated rates of urea (0, 67, 134, and 202 kg N ha - 1 ) and four weed removal timings (5, 10, 15, and 20 cm) based on average weed canopy height. An additional season- long w... |
51. Residual Effects of Nitrogen Fertilization on Soil Nitrogen Pools and Corn GrowthNitrogen (N) fertilization of corn (Zea mays L.) may increase, decrease, or not affect the N supplying capacity of the soil. Six field-scale corn N rate trials were established in corn-soybean rotations in diverse soil types across Indiana. Six N rates ranging from about 25 to 270 lb N ac-1 were replicated 4 to 6 times at each site and re-applied to the same plots for each of four corn crops. In the fifth corn season, 2015, half of the replications at each location were sup... M. Moser, R. Nielsen, J. Camberato |
52. Respiration as a Measure of Soil Health: Challenges and OpportunitiesIn recent years, respiration has become a commonly-used soil health metric. It has been used as a standalone predictor of soil N supplying capacity and in conjunction with other metrics to assess overall soil health. However, the sources of variation underlying respiration itself have not been thoroughly assessed. We show that across growing regions in California, respiration was unable to accurately predict soil N supply. The R2 values were much higher in fields that had received a rece... J. Wade, S. Culman, T. Hurriso, W. Horwath, R. Miller |
53. Response of Continuous Corn to Varying Rates and Placements of Starter FertilizerPrevious research has shown that starter fertilizer, a small amount of fertilizer placed with or near the seed at planting, often accelerates early season growth and increases biomass production, but does not always increase grain yield in corn (Zea mays L.). Our objective was to evaluate the effects of starter fertilizer on crop growth and development, as well as grain yield and moisture in continuous corn cropping systems. Treatments consisted of no fertilizer applied at planting (Cont... C. Hornaday, J. Camberato, R. Nielsen |
54. Slow-Release Fertilizer Effect on Groundwater Nitrogen Concentration in Sandy Soils under Potato ProductionCurrent nitrogen (N) fertilizer management practices for potato farming have led to elevated levels of N in the local groundwater. Slow-release fertilizer, specifically Environmentally Smart Nitrogen® (ESN®) polymer coated urea (PCU ) may reduce the amount of N leaching to groundwater; however no field scale studies have been performed in Wisconsin to validate these assertions. Field experiments were conducted at the Hancock Agricultural Research Station using Russet Burbank potato, planted i... |
55. Soil Health: Approaches in Fertility ManagementInconsistent grain yield and in some cases variable yield response to fertilizer inputs suggest improving fertility management strategies with greater emphasis towards resilient cropping systems may also improve nutrient efficiency. The soil microbiome may affect nutrient mineralization, nutrient movement to roots, disease incidence, and other specialized relationships (e.g., nodule formation in soybean (Glycine max L.)). Although within-field grain yield variability has correla... K. Steinke |
56. 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 ... F. Hansel, D. Ruiz diaz, L. Rosso |
57. Starter Fertilizer Slows the Movement of Corn Roots Across the RowApplications of starter fertilizer may alter the root morphology of young developing plants by causing lateral roots to proliferate when the root system enters the highly concentrated fertilizer band. This may affect the timing of root movement across the row when starter fertilizer is used. The timing of root movement across the row was determined by placing 20 12-inch-long perforated cylinders vertically in the soil at the V2 leaf stage. The cylinders were placed approximately every 15&rdqu... J. Lee, J. Camberato, R. Nielsen |
58. Survey of the Tissue Nutrient Status of Winter Wheat in KentuckyA field survey conducted in western Kentucky (KY) was initiated to determine if University of Kentucky soil fertility recommen dations for winter wheat production was adequate. Twenty- nine fields in 15 western KY counties were iden tified by county extension agents for sampling. Soil and tissue samples were collected for anal ysis in a 150 foot by 150 foot sampling area. Approximately 100 flag leaf samp les were collected, air-dried, ground, and analyzed for N, P, K, Mg, Ca, S, B, Zn, Mn, Fe, ... |
59. Switchgrass Response to Nitrogen: Trade-offs between Quantity and QualityIn 2009 and 2010, a study was conducted at four loca tions in southwest Wisconsin to determine optimal nitrogen (N) fertilizer rates and harvest timings for switchgrass quantity and quality. The study was conducted as a randomized complete bloc k, split plot design with five main plot treatments (0, 56, 112, 168, and 224 kg ha -1 of N) and three split plot treatments (mid-fall, late- fall, and early spring harvest). Dry matter (D M) yields increased between 2009 and 2010 and were most often max... |
60. The Anaerobic Potentially Mineralizable Nitrogen Test as a Tool for Nitrogen Management in the MidwestThe anaerobic potentially mineralizable nitrogen (PMNan) test is a tool that can improve estimations of mineralizable nitrogen (N) and enhance nitrogen use efficiency. This tool may also help improve predictions of N uptake, grain yield, and the economic optimum nitrogen rate (EONR) of corn (Zea mays L.). A 32 site-year study across eight US Midwestern states was conducted to 1) compare the effect of incubation length (7-, 14-, 28-d), soil sampling timing, N fertilizer rate, and thei... J. Clark, K. Sloan veum, F. Fernandez, J. Camberato, P. Carter, R. Ferguson, D. Franzen, N. Kitchen, C. Laboski, E. Nafziger, J. Sawyer, J. Shanahan |
61. Tillage and Nitrogen Responses to Residue Removal in Continuous CornWith the growing interest in harvesting corn stal k residue for use as biofuel comes the need to examine how residue removal might affect yield a nd N needs of the subsequent corn crop. We are conducted an experiment over the past five years ( 2006 to 2010) at four Illinois locations (three in Mollisols and one in Alfisol) in which all, part, or none of the corn residue is removed, followed by tilled and no-till split within each residue treatment, a nd with N rates split within each residue-til... |
62. 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 e... S. Berg, P. Sexton, R. Gelderman, A. Bly, C. Derdall |
63. Topsoil Thickness Effects on Phosphorus and Potassium Dynamics on Claypan SoilsDue to variable depth to claypan (DTC) across landscapes, nutrient supply from subsoils, and crop removal, precise P and K fertilizer management on claypan soil fields can be difficult. Therefore, a study was performed to determine if DTC derived from soil apparent electrical conductivity (ECa) could be used to improve P and K management for corn (Zea mays L.) and soybean (Glycine max [L.]). Research was conducted on a claypan soil at the University of Missouri&rsq... L. Conway, M. Yost, N. Kitchen, N. Kitchen, K. Sudduth |
64. Validating Potassium Fertilizer Guidelines in Alfalfa-corn RotationsIn 2008 to 2010, on-farm research was conducted on 10 fields with medium soil test K (STK) to validate Minnesota K fertilizer guidelines by determining the effect of K fertilizer applications on alfalfa yield and quality in its last production year, and estimating the carryover of excess fertilizer K to first-year corn. We were surprised to find that no K fertilizer was needed to maximize alfalfa yield or overall forage feed value and quality. Luxury consumption of K occurred because as K applic... |
65. Variability of Soil Test Potassium in Space and TimePotassium soil test may be highly variable within fields. In the western part of the North Central Region, where the history of K fert ilization is marked by low rates of K fertilizer and fields where K has never been applie d, natural variability of K is governed by clay content and landscape position. In areas where K fertilization has been high, man-made variability is more common. Man-made variability may be experienced as differences in historic rates within fields merged over years of own... |
66. Variation in Internal N Efficiency of Corn and Impact on Yield-Goal Based N RecommendationsInternal N efficiency (IE) is defined as bushels per acre (GY) produced per pound of N per acre (PMN) in the plant at physiological maturity (R6). Internal N efficiency defines the required amount of plant N content at R6 in a yield-goal based N rate recommendations (currently used in 30 U.S. states) and several commercial N recommendation models. Commonly IE is assumed to be constant at an approximate value of 0.8 bu lb-N-1 in yield-goal based recommendations. Our research objective was... M. Shafer, J. Camberato, P. Carter, R. Ferguson, F. Fernandez, D. Franzen, N. Kitchen, C. Laboski, E. Nafziger, R. Nielsen, J. Sawyer, J. Shanahan |
67. What Can Long Term Experiments Provide for Improving Phosphorus and Potassium Management?Agricultural research utilizes both short-term and long-term experiments. Short-term experiments provide useful information on how a system is affected at the time of management changes, and evaluate short-term responses by the soil or crop. Agricultural systems are complex systems with multiple components that operate on different time scales of response, however. Therefore, the initial response of either the whole system or individual components may not necessarily indicate the direction or... A. Mallarino |
68. Winter Annual Weeds Affect Nitrogen Availability for No-Till CornWinter annual weeds effects on nitrogen availability have not been adequately studied. The objective of this study was to determine winter annual weed s effects on nitrogen availability for rainfed no -till corn (Zea mays L.) following soybeans ( Glycine max L. Merr.). Field research was conducted in 2010-2011 at 14 sites with heavy winter annual weed pressure in eastern Kansas. A two -factor factorial arrangement in a randomized complete block design with three replications included t hree her... |
69. Winter Wheat Growth and Grain Yield Response to Individual Agronomic InputsProducers’ interested in optimizing wheat (Triticum aestivum L.) growth and yields have adopted intensive (i.e. high-input) wheat management systems in Michigan. Additional research is required to evaluate growth, grain yield, and profitability of multiple and individual agronomic inputs. An omission field trial was initiated in Lansing, MI during 2015 to evaluate the response of soft red winter wheat to six agronomic inputs in enhanced (high-input) and traditional (low-input) ... D. Quinn, K. Steinke |