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Division A-3 - Agroclimatology and Agronomic Modeling
Modeling Temporal Runoff Patterns in a 3D Simulated Watershed: an Application of the ZOO Desktop Experiment Management Environment. M.C. Anderson*, J.M. Norman, Y.E. Ioannidis, M. Livny, and A. Ailamaki, Univ. Wisconsin-Madison.
A New Observing System for Agricultural Meteorology GOES and ASOS/AWOS. W.L. Bland, M.C. Anderson, J.M. Norman, and G.R. Diak, Univ. Wisconsin-Madison.
Prediction of Alfalfa Forage Yield Loss Due to Freezing Injury. V.R. Kanneganti*, R.P. Walgenbach, W.L. Bland, D.J. Undersander and C.A. Rotz, USDA-ARS-US Dairy Forage Research Center/Univ. Wisconsin-Madison.
Division A-4 - Extension Education
Nutrient Management: What's Happening in the Midwest. K.A. Kelling* and S.J. Sturgul, Univ. Wisconsin-Madison.
Division A-5 - Enviromental Quality
Effect of 15 Years of Biosolids Application on Crops and Soil Phosphorus. A.E. Peterson*, R.P. Wolkowski, P.E. Speth, T.H. Wright, and P.L. Schlecht. Univ. Wisconsin-Madison and Milwaukee Metropolitan Sewerage District.
Computer Software Division
Landscape View of Soil Biology. R.F. Harris*, P. Barak, E.J. Tyler, and K. McSweeney. Univ. Wisconsin-Madison.
Bridging the Gap Between GIS, Soil Quality, and Models of Agricultural Production, Protection and Profitability. R.F. Harris*, S.J. Ventura, B. Lowery, R.P. Wolkowski, and K. McSweeney. Univ. Wisconsin-Madison.
ZOO A Management System for Complex Agronomic Models. Y.E. Ionnadis, M. Livny, A. Ailamaki, M.C. Anderson, and J.M. Norman, Univ. Wisconsin-Madison.
Web Home Pages for Soil Microbiology and Biochemistry Instruction. A.G. Wollum*, D.M. Sylvia, and W.J. Hickey, NC State Univ., Univ. Flor. and Univ. Wisconsin-Madison.
Division S-2 - Soil Chemistry
Acid/Base Fluxes in the Root Zone of Agricultural Soils: Implications for Rhizosphere Chemistry. P. Barak, Univ. Wisconsin-Madison.
Spectroscopy and the Bonding of Metals and Other Non Structural Elements in Humic Substances. P.R. Bloom* and W.F. Bleam, Univ. of Minnesota and Univ. Wisconsin-Madison.
Nuclear Magnetic Resonance Studies of Humic Micellar Solutions Solubilization and Partitioning. Y.Y. Chien and W.F. Bleam, Univ. Wisconsin-Madison.
Mineralization of Organically Bound Soil Phosphorus by Plant Enzymes. X. He* and P.A. Helmke, Univ. Wisconsin-Madison.
Microscale Measurements of Cation and Alkalinity Diffusion in Soils with Custom-Made Ion-Selective Microelectrodes. L.A. Sherman and P. Barak, Providence College and Univ. Wisconsin-Madison.
Redox Behavior of Cr Contaminated Soils Cr, Fe, and Mn XANES Analysis. M.D. Szulczewski*, P.A. Helmke, and W.F. Bleam, Univ. Wisconsin-Madison.
XANES Studies of Sulfur in Natural Organic Matter. K. Xia*, W.F. Bleam, P.R. Bloom, U. Skyllberg and P.A. Helmke, Univ. Wisconsin-Madison, Univ. Minnesota-St. Paul and Swedish Univ. Agricultural Sciences.
Interactions of Indigenous Levels of Trace Elements with Major Cations in the Soil-Water System. K. Xia* and P.A. Helmke, Univ. Wisconsin-Madison.
Division S-3 - Soil Biology and Biochemistry
Mechanistic Interpretation of Xenobiotic Bioavailability in Humic Micellar Solutions. E.G. Kim*, W.J. Hickey, and W.F. Bleam, Univ. Wisconsin-Madison.
Web Home Pages for Soil Microbiology and Biochemistry Instruction. A.G. Wollum*, D.M. Sylvia, and W.J. Hickey, NC State Univ., Univ. Flor. and Univ. Wisconsin-Madison.
Division S-4 - Soil Fertility and Plant Nutrition
Nitrogen Availability to Corn Following Small Grains. T.W. Andraski* and L.G. Bundy, Univ. Wisconsin-Madison.
Predicting Optimum Nitrogen Rates for Corn in Soybean-Corn Rotations. K.A. Schoessow, L.G. Bundy, and K.C. Kilian, Univ. Wisconsin-Madison and Univ. Wisconsin-Platteville.
Long-Term Crop Rotation Effects on Soil Nitrogen Availability. C.C. van Schaik* and L.G. Bundy, Univ. Wisconsin-Madison.
Division S-6 - Soil and Water Management and Conservation
Measured and Modeled Water Budget Components for Corn and a Natural Prairie Over an Annual Cycle. K.R. Brye*, J.M. Norman, L.G. Bundy, and S.T. Gower, Univ. Wisconsin-Madison.
Division S-8 - Nutrient Management and Soil and Plant Analysis
Effects of Nitrogen Fertilizer Efficiency on Soil Chemical Properties. M. Avila-Segura, P. Barak, and D.A. Laird, Univ. Wisconsin-Madison and USDA, ARS, NSTL.
Stable Isotope Dilution for the Determination of Selenium in Plant Samples with Inductively Coupled Plasma Mass Spectrometry. S.M. Combs and L.S. Zhang, Univ. Wisconsin-Madison/Ext.
Influence of NH4-K Interactions on NO3 Leaching. J. Wu, D.A. Laird*, D.L. Karlen, P.D. Fleming, P. Barak, Iowa State Univ., USDA, ARS, NSTL, and Univ. Wisconsin-Madison.
Division S-9 - Soil Mineralogy
Magnetic Susceptibility and X-Ray Absorption Studies of Ion Dispersal on Oxide Surfaces. K. Xia, W.F. Bleam*, P.A. Helmke, and F.J. Weesner, Univ. Wisconsin-Madison and Los Alamos National Laboratory.
Polarized X-Ray Absorption and Magnetic Studies of Oriented Clay Films Metal Adsorption by Pillared Clay. S. Yoon* and W.F. Bleam, Univ. Wisconsin-Madison.
Division S-11 - Soils and Environmental Quality
Management of By-Products. L.R. Cooperband*, and T.J. Logan, Univ. Wisconsin-Madison and The Ohio State University.
Workshop - Hypoxia Around the World: Causes and Solutions
Today's Nitrogen Best Management Practices and Needed Changes. K.A. Kelling*, C.W. Rice, and S.J. Sturgul, Univ. Wisconsin-Madison, and Kansas State Univ.
Division A-3 - Agroclimatology and Agronomic Modeling
Modeling Temporal Runoff Patterns in a 3D Simulated Watershed: an Application of the ZOO Desktop Experiment Management Environment. M.C. Anderson*, J.M. Norman , Y.E. Ioannidis, M. Livny, and A. Ailamaki, Univ. Wisconsin-Madison.
With the recent advent of sub-meter digital elevation modeling (DEM) capabilities, it is becoming possible to model surfacewater flow in great detail. The Runoff_ALEX modeling system executes an energy balance/infiltration model (ALEX: Atmosphere Land Exchange) at every pixel in a DEM, using slope information from the DEM to route excess surface water between pixels. While this type of approach effectively utilizes high resolution surface data, the bookkeeping, memory management and data transfer logistics involved in processing large DEMs can be overwhelming. The ZOO Desktop Experiment Management Environment, developed at the UW, provides a user-friendly means of handling such large modeling experiments, and orchestrating communication between models and large input/output databases. We demonstrate how a 3D runoff model can be implemented under ZOO, and how ZOO can be used to efficiently explore the spatio-temporal information database generated by the model.
Martha Anderson, 608-265-3288, anderson@bob.soils.wisc.edu.
A New Observing System for Agricultural Meteorology GOES and ASOS/AWOS. W.L. Bland, M.C. Anderson, J.M. Norman, and G.R. Diak, Univ. Wisconsin-Madison.
Weather observations of interest to agricultural meteorology are increasingly available in real time from new automated weather station networks operated by the National Weather Service and Federal Aviation Administration, and from products derived from the NOAA GOES satellites. These observation systems enjoy support from federal, state, and local weather and aviation interests, although AWOS programs vary by state. Ever improving computer communications, storage and power meant that these data streams can be captured for archiving and, combined with computer modeling, analyzed for quality and reprocessed into specific information products. Applications to date include: evapotranspiration estimates, continuous correction of model forecasts, thermal time maps, wind data for agrichemical drift assessment, and canopy humidity estimates for disease modeling.
William L. Bland, 608-262-0221, wlbland@facstaff.wisc.edu.
Prediction of Alfalfa Forage Yield Loss Due to Freezing Injury. V.R. Kanneganti*, R.P. Walgenbach, W.L. Bland, D.J. Undersander and C.A. Rotz, USDA-ARS-US Dairy Forage Research Center/Univ. Wisconsin-Madison.
Freezing injury causes extensive yield loss in alfalfa exposed to severe winters in cold climates. Alfalfa models must simulate freezing injury effects in a cumulative way so that forage yield can be accurately predicted over multiple years of a crop. A simulation model, ALFACOLD, was developed by integrating functions of cold tolerance, fall dormancy and freezing injury into the ALSIM1 (Level 2) alfalfa model. The ALFACOLD model predicts forage yield on a daily basis while simulating freezing injury over multiple years of the same crop. The model was tested against measured yield from 39 cultivars seeded in two years and monitored for three years after seeding at two sites in Wisconsin. Averaged over sites and years, the model predicted annual yield within 18% of the measured yield. The model can be used to forecast potential yield loss due to freezing injury in the preceding winter as a function of cultivar and weather.
V.R. Kanneganti, 608-264-5372, raok@dfrc.wisc.edu.
Division A-4 - Extension Education
Nutrient Management: What's Happening in the Midwest. K.A. Kelling* and S.J. Sturgul, Univ. Wisconsin-Madison.
Nutrient management planning in the Midwest has attempted to raise farmer awareness of the viability of on-farm nutrient sources including legumes and manure. Although some variation exists among the Midwestern states, a survey of state nutrient management specialists showed that a planning process exists in most states, it typically uses the university soil fertility recommendation as its base, and the implementation of these programs is generally limited to identified critical areas. Educational activities have emphasized on-farm demonstrations, implementation of nutrient crediting through privat eindustry such as dealer agronomists and crop consultants, and development of increasingly refined crediting guidelines. While the process for developing plans has progressed well in most states, it is less clear what proportion of prepared plans have been implemented or what impact these plans have had on water quality.
K.A. Kelling, 608-263-2795, kkelling@facstaff.wisc.edu.
Division A-5 - Enviromental Quality
Effect of 15 Years of Biosolids Application on Crops and Soil Phosphorus. A.E. Peterson*, R.P. Wolkowski, P.E. Speth, T.H. Wright, and P.L. Schlecht. Univ. Wisconsin-Madison and Milwaukee Metropolitan Sewerage District.
Since biosolids contain considerable amounts of plant nutrients, recycling of these nutrients may benefit agricultural crops and be environmentally safe. Experiments to study these effects were established in 1979 on the Walworth County Farm, Elkhorn, WI on Plano silt loam (prairie) soil. Corn is grown as the indicator corp. Twenty-two groundwater wells were installed to depths of 8 to 10 m and are sampled bimonthly. Treatments are untreated, fertilizer, 6.6 (the normal rate) or 13.3 T ha-1. Corn yields and tissue analysis have indicated no toxic effect from any biosolid application. No heavy metal movement has been found below the tilled soil. Nitrate concentrations have increased in the heavy biosolids treatment. After 15 years of biosolids application, no detrimental effect on plant growth or Zn update is shown, regardless of the soil P of the plow layer which now measures 52, 220, 340 and 183 mg kg-1, respectively for the check, 6.6, 13.3 T ha-1, and the fertilizer treatment. There seems to be no reason to limit biosolids P application to that removed by the crop from the effect on the environment. Also the comparative risk assessments for methods of biosolids disposal show land application to have the least risk.
A.E. Peterson, 608-262-2631, aepeters@facstaff.wisc.edu.
Computer Software Division
Landscape View of Soil Biology. R.F. Harris*, P. Barak, E.J. Tyler, and K. McSweeney. Univ. Wisconsin-Madison.
A computer-driven, multimedia program provides pictorialized instruction on interconnections between landscapes, soil profiles, soil quality and health, and forms and functions of the above- and particularly the below-ground plant, animal and microbial inhabitants of terrestrial ecosystems. Sources of images include the S-3 soil biology and biochemistry and Marbut landscape and soil profile slide sets, virtual reality soil and plant nutrition animations, and photographic image-linked geographic information systems of UW Agricultural and Natural Resource Research Stations. The version of the program used for this presentation is oriented towards a college level introductory soil science audience.
R.F. Harris, 608-263-5691, rfharris@facstaff.wisc.edu.
Bridging the Gap Between GIS, Soil Quality, and Models of Agricultural Production, Protection and Profitability. R.F. Harris*, S.J. Ventura, B. Lowery, R.P. Wolkowski, and K. McSweeney. Univ. Wisconsin-Madison.
A GIS initiative for the UW Arlington Agricultural Research Station provides a framework for defining the roles of soil quality, other GIS data, and models in land management for integrated crop production, environmental protection and economic profitability. An interactive ArcView data base integrates photographic images with layers of information on fields and buildings, land use, crop yields, and soil, topographic, hydrologic and geologic characteristics. Investigations of site-specific agricultural management practices linked to GIS and simulation modeling of crop production and environmental quality are facilitated. An illustrative research project focuses on the effect of landscape position (specifically critical site minibasin and slope properties) on crop production and nonpoint pollution transport. The GIS helps researchers and farmers work together to develop site-specific management practices that protect the environment while keeping agriculture profitable and sustainable.
R.F. Harris, 608-263-5691, rfharris@facstaff.wisc.edu.
ZOO A Management System for Complex Agronomic Models. Y.E. Ionnadis, M. Livny, A. Ailamaki, M.C. Anderson, and J.M. Norman., Univ. Wisconsin-Madison.
The ZOO Desktop Experiment Management Environment has been under development for the past few years by a team of Computer Scientists in close collaboration with scientists from several disciplines. ZOO enables scientists to manage and observe their experiments and associated data from their desk. It provides a uniform visual interface that can be used throughout the life-cycle of experimental studies. Moreover, ZOO can be connected to a wide variety of software tools, models, and instruments, allowing scientists to control and monitor the experiment flow from a central point. At the core of ZOO is an object-oriented database system, which supports all the other modules of the environment, including visual design and query interfaces and data translation engines. This demonstration will feature a ZOO-based Experiment Management System customized to a watershed runoff model. We will show how the system can be used in all phases of the modeling process: in model development and execution, and in database assembly and exploration.
Martha Anderson, 608-265-3288, anderson@bob.soils.wisc.edu.
Web Home Pages for Soil Microbiology and Biochemistry Instruction. A.G. Wollum*, D.M. Sylvia, and W.J. Hickey, NC State Univ., Univ. Flor. and Univ. Wisconsin-Madison.
The purpose of the demonstration is to show examples of materials associated with our soil microbiology courses, which are located on course homepages accessible through the World Wide Web. Different ways to display course syllabi, schedules and outlines will be featured. Problem sets with form options for electronic submission of answers will be demonstrated. The use of password protected information will also be shown, especially related to figures and tables, associated with the lecture materials. A simple interactive problem will also be shown to illustrate some of the uses of the web for teaching.
A.G. Wollum, 919-515-1460, Arthur_Wollum@ncsu.edu.
Division S-2 - Soil Chemistry
Acid/Base Fluxes in the Root Zone of Agricultural Soils: Implications for Rhizosphere Chemistry. P. Barak, Univ. Wisconsin-Madison.
Acid-forming fertilizer inputs in modern production agriculture may potentially contribute 25 kmol H(^+) ha(^-1) yr(^-1), which may exceed acid rain inputs by fiftyfold. Some of the acidity generated may be consumed by plant assimilative processes and may be expressed as either alkalinity generation at the rhizoplane or storage in aboveground plant parts for either harvest or return as residue. Proton/alkalinity fluxes on the millimeter scale at the rhizoplane will affect availability of nutrients from insoluble sources.
Phillip Barak, 608-263-5450, pwbarak@facstaff.wisc.edu.
Spectroscopy and the Bonding of Metals and Other Non Structural Elements in Humic Substances. P.R. Bloom* and W.F. Bleam, Univ. Minnesota and Univ. Wisconsin.
Spectroscopic techniques allow the direct determination of bonding environments in humic substances. Electron spin resonance (ESR) which is limited to species with unpaired electrons, has been used for the study of some metal ions; e.g. Mn2+ and Cu2+. Nuclear magnetic resonance is limited to isotopes with odd mass numbers and until recently has not been sufficiently sensitive for the study of minor components. New high-field instruments, however, have much greater sensitivity allowing for the study of some minor components: e.g. Cd and P. X-ray absorption near-edge spectroscopy (XANES) and x-ray absorption fine structure spectroscopy (XAFS) are very powerful techniques, applicable to all but very light elements. They have been used for the determination of oxidation sates (e.g. S) and the determination of bond lengths and bond symmetry (e.g. Hg2+).
Paul R. Bloom, 612-646-1985, pbloom@soils.umn.edu.
Nuclear Magnetic Resonance Studies of Humic Micellar Solutions Solubilization and Partitioning. Y.Y. Chien and W.F. Bleam, Univ. Wisconsin-Madison.
The sorption of organic compounds by humic substances, though poorly understood, is believed to resemble a partitioning phenomena with the organic distributed between aqueous solution and the humic substances. We exploit the colloidal properties of humic substances, most notably their capacity to form micellar solutions, to study the partitioning of organic contaminants into humic micellar aggregates and the internal structure of humic aggregates. Our results show that atrazine enters the humic micellar interior, anchored by hydrogen-bonding interactions. Organic solvents swell humic micelles, in some cases resulting in hydrocarbon:humic ratios of nearly 2:1 without phase separation. Two-dimensional nuclear Overhauser effect spectroscopy (NOESY) reveals at least two structural domains: aromatic-rich region and a combined oxygen- containing/aliphatic region.
William F. Bleam, 608-262-9956, wfbleam@facatsff.wisc.edu.
Mineralization of Organically Bound Soil Phosphorus by Plant Enzymes. X. He* and P.A. Helmke, Univ. Wisconsin-Madison.
We hypothesize that the efficacy of soil enzymes to mineralize P bound to soil organic matter (SOM) is greatly increased if the metals normally bound to SOM are removed by plant-secreted metal complexing agents. Our research indicates that this effect is expressed to a large degree in sweet white lupin (Lupinus albus L. var. Ultra). Plant enzymes and the metal complexing agents are released from lupin roots in response to P deficiency. Lupin utilizes part of the soil organic P pool as an adaptive strategy to P deficiency. Effects of the plant enzymes have been studied by 31P NMR spectroscopy, ICP and HPLC analysis. Effects of metals on the ability of phosphatase and phytase to mineralize soil organic P compounds have been determined with Plano soil treated with metal complexing agents. Organic acids from root exudates remove some of the bridging Al and Fe atoms in the SOM and this peptizes soil organic colloids. Acid phosphatase and phytase from the root exudates have been found. This phenomenon is an important and unrecognized part of the P cycle for plants in natural and agricultural soils.
Philip A. Helmke, 608-263-4947, pahlemke@facstaff.wisc.edu.
Microscale Measurements of Cation and Alkalinity Diffusion in Soils with Custom-Made Ion-Selective Microelectrodes. L.A. Sherman and P. Barak, Providence College and Univ. Wisconsin-Madison.
The development over time of microscopic cation and pH gradients in soils in contact with dolomitic agliming materials were measured successfully. To eliminate suspension effects measured by electrodes in heterogeneous systems, a solid-state microelectrode was used as reference in conjunction with the ion-selective microelectrodes. Gradients of Ca(^2+) showed an interesting trend of decreased Ca(^2+) activity in the region of high pH near the interface of the aglime and the soil, apparently due to precipitation of calcite. Movement of Ca(^2+) against its gradient appears to have occurred in this region, requiring explanations of charge coupling derived from irreversible thermodynamics. Corresponding gradients of soluble Mg(^2+), as well as exchangeable Mg(^2+), measured in soil extracts from destructive sampling of the cell, did not indicate any precipitation, in agreement with the lack of observed magnesite or dolomite precipitation in the laboratory.
Leslie A. Sherman, 401-865-1000, lsherma1@students.wisc.edu.
Redox Behavior of Cr Contaminated Soils Cr, Fe, and Mn XANES Analysis. M.D. Szulczewski*, P.A. Helmke, and W.F. Bleam, Univ. Wisconsin-Madison.
Our previous results show that X-ray Absorption Near-EdgeSpectroscopy (XANES) can successfully measure Cr(VI):Cr(III) ratios. According to these XANES analyses, less than 50% of the total Cr was present as Cr(VI), even in the most contaminated soils, yet Cr(VI), the soluble, toxic species, persists for decades in contaminated soils. The persistence of chromate in contaminated soils must result from a combination of factors that prevent complete reduction of the chromate anion, retain Cr(VI) by adsorption to soil minerals, and/or involve the re-oxidation of Cr(III) to Cr(VI) in the soil chemical equilibrium. Iron (II) may reduce Cr(VI) while Mn(IV) may oxidize Cr(III). We can determine this residual reducing or oxidizing capacity in chromium contaminated soils by measuring the average oxidation state of iron and manganese by XANES analysis at the Fe and Mn K-edges.
William F. Bleam, 608-262-9956, wfbleam@facstaff.wisc.edu.
XANES Studies of Sulfur in Natural Organic Matter. K. Xia*, W.F. Bleam, P.R. Bloom, U. Skyllberg and P.A. Helmke, Univ. Wisconsin-Madison, Univ. Minnesota-St. Paul and Swedish Univ. Agricultural Sciences.
It has been demonstrated that sulfur K edge x-ray absorption near edgespectroscopy (XANES) can be used to speciate the major functional forms of sulfur in a variety of geochemical samples ranging from petroleum and coal to marine sediments. Only recently this technique was used to study organo-S speciation in humic substances. Organo-S speciation in humic acids and whole soils originated from different environmental settings were studied using both XANES and NMR. The relationship between organo-S speciation and the environmental settings of the samples will be discussed in this paper.
Kang Xia, 608-262-0397, kxia@students.wisc.edu.
Interactions of Indigenous Levels of Trace Elements with Major Cations in the Soil-Water System. K. Xia* and P.A. Helmke, Univ. Wisconsin-Madison.
The effects of major cations on the indigenous concentration activities of trace elements in the solution phase of the soil-water system were studied in isolation from the effects of soil reactions by probing the solution with small additions of metals and complexing reagents. Soil samples from various soil orders were studied to give a range in values of soil mineralogy, pH, organic matter, and soluble salts. Samples of soil solutions were obtained by water saturation extracts of these soils. The concentrations of total dissolved trace elements were determined by ICP-MS. The activities of the free-hydrated trace element cations were measured by Donnan membrane equilibrium analysis and ICP-MS. The exchangeability of trace element cations bound with water soluble soil organic matter will be discussed in this paper.
Kang Xia, 608-262-0397, kxia@students.wisc.edu.
Division S-3 - Soil Biology and Biochemistry
Mechanistic Interpretation of Xenobiotic Bioavailability in Humic Micellar Solutions. E.G. Kim*, W.J. Hickey, and W.F. Bleam, Univ. Wisconsin-Madison.
Our study examines whether sorption of a nonpolar organic substrate in concentrated humic acid solutions alters the bioavailability of the substrate. Concentrated humic acid solutions enhance the apparent solubility of nonpolar organic compounds, probably through a partitioning mechanism into humic molecular aggregates or micelles. Earlier researchers have studied the bioavailability of nonpolar organics solubilized by synthetic surfactant micelles, but these studies often find a toxic effect due to the surfactant. Our system consists of a 2 to 6% humic acid solution at pH 8 containing potassium phosphate buffer. The substrate is C-14 labeled biphenyl and the organism is Alcaligenes eutrophus (strain H850), a biphenyl degrading bacteria. The study measures the biodegradation rate, quantifying both evolved carbon dioxide and unreacted substrate remaining in the humic solution. Concentrated humic solutions, though capable of increasing the apparent solubility of biphenyl, did not prove toxic to A. eutrophus (strain H850).
W.F. Bleam, 608-262-9956, wfbleam@facstaff.wisc.edu.
Web Home Pages for Soil Microbiology and Biochemistry Instruction. A.G. Wollum*, D.M. Sylvia, and W.J. Hickey, NC State Univ., Univ. Flor. and Univ. Wisconsin-Madison.
The purpose of this presentation is to share our experiences of ways we have used the World Wide Web in soil microbiology instruction. We advocate that each course should have its own home page. The website provides prospective and enrolled students relevant course information such as course syllabus, schedule, reading assignments, outlines, problem sets and answers, review questions and links to microbiology sites around the world. Homework can be submitted electronically via email or the forms option on the web page. Powerpoint presentations in the classroom can be easily adapted as web page lecture outlines, as well as including graphic displays. If necessary this information can be password protected, accessible only to students registered in the class. Also interactive problem sets can be devised which provide the student opportunities to solve what if questions. While internet technology provides exciting opportunities in teaching, it should be used in conjunction with extensive instructor-student interactions to maximum learning opportunities.
A.G. Wollum, 919-515-1460, Arthur_Wollum@ncsu.edu.
Division S-4 - Soil Fertility and Plant Nutrition
Nitrogen Availability to Corn Following Small Grains. T.W. Andraski* and L.G. Bundy, Univ. Wisconsin-Madison.
Nitrogen rate recommendations for corn are generally reduced following legumes compared to following corn or small grains. A 4-yr field study was conducted on a Plano silt loam soil in southern Wisconsin to evaluate the capability of soil NO3 tests to predict N availability to corn following small grains. Previous crop small grains included winter wheat, winter rye, and oat harvested for grain and straw. Nitrogen fertilizer was applied to corn at rate of 0 to 204 kg ha-1 in 34-kg increments. Grain yields were obtained and economic optimum N rates were determined. Optimum N rates following small grains ranged from 0 to 100 kg ha-1 and were substantially lower than the N rate usually recommended for corn following corn (180 kg N ha-1). Soil NO3-N contents in the top 90 cm increased by 80 to 100 kg ha-1 between preplant and presidedress sampling times. End-of-season soil profile NO3-N contents were about 110 kg ha-1 lower where observed optimum N rates were applied compared to the standard N rate recommendation. In addition to corn yield benefits from small grains to crop rotations, small grains may also enhance soil N availability thus potentially reducing the fertilizer N needs to corn.
T.W. Andraski, 608-265-5370, andraski@facstaff.wisc.edu.
Predicting Optimum Nitrogen Rates for Corn in Soybean-Corn Rotations. K. A. Schoessow, L.G. Bundy*, and K.C. Kilian, Univ. Wisconsin-Madison and Univ. Wisconsin-Platteville.
Soybean-corn rotations are widely used for grain production in the Midwest. Variability in N fertilizer requirements for corn (Zea mays L.) following soybean (Glycine max L.) across sites and years emphasizes the need to understand management practice effects on apparent soybean N contributions and to determine the ability of soil nitrate tests and other N availability tests to predict economic optimum N rates (EONR) in soybean-corn sequences. Field experiments with three soybean residue treatments and five N rates (0 to 179 kg N/ha) applied to corn were conducted for 3 yr at four locations on medium-to fine-textured soils. Soil nitrate tests, a phosphate-borate buffer test, and the UV absorbance of NaHCO3 soil extracts at 200 and 260 nm (UV200 and UV260) were evaluated at three sampling times (preplant, emergence, and pre- sidedress) for their ability to predict EONR for corn following soybean. Soybean residue management usually did not affect corn EONR which ranged from 0 to 179 kg N/ha across sites and years. The preplant nitrate test with an additional 45 kg N/ha adjustment or the UV260 test were effective in identifying EONR for corn following soybean.
L.G. Bundy, 608-263-2889, lgbundy@facstaff.wisc.edu.
Long TermCrop Rotation Effects on Soil Nitrogen Availability, C.C.van Schaik* and L.G. Bundy. Univ. Wisconsin-Madison.
Crop rotations can have a profound effect on the availability of nitrogen to plants. We studied the effects of rotation, previous crop, and N fertilization history on N availability in spring-sampled soil from field plots immediately before corn production. Soils (0-20 cm) came from 21 phases of seven rotations incorporating corn (Zea mays L.), soybean (Glycine max L.), alfalfa (Meticago sativa L.), and/or oat (Avena sativa L.) in a 30-yr study on Rosetta silt loam soil near Lancaster, WI. The study included four N rates (0 to 224 kg N/ha) applied to corn. All soils were brought to 60% water-filled pore space, incubated at 25 oC for 16 wk and analyzed biweekly for inorganic N. A second method in which evolved CO2 was captured during an aerobic 24-hr incubation was applied to the same soils. Initial findings indicate more mineralized N when the rotation included at least one crop other than corn. Net N mineralization following soybean was less than that following alfalfa. Residual benefits on N mineralization from forage legumes in a rotation appear negligible after the third year of corn. Results of the more rapid CO2 evolution method were compared with the results of the aerobic 16- wk incubation as well as with yield data.
C.C. van Schaik, 608-263-3878, ccvansch@students.wisc.edu.
Division S-6 - Soil and Water Management and Conservation
Measured and Modeled Water Budget Components for Corn and a Natural Prairie Over an Annual Cycle. K.R. Brye*, J.M. Norman, L.G. Bundy, and S.T. Gower, Univ. Wisconsin-Madison.
The balance of moisture inputs and outputs for an ecosystem influences many processes within the soil environment. The components of the water budget for a chisel plow and no-till corn, and a natural prairie ecosystem were continuously monitored over the annual cycle of 1996. The ecosystems reside on a silt loam soil with similar soil physical properties, and climatic and physiographic characteristics. The drainage component was measured using physiographic characteristics. The drainage component was measured using suction plate, pan lysimeters. Evapotranspiration estimates were obtained by calculating a residual difference from each water budget. Annual measured drainage from the prairie, no-till corn, and chisel plow corn ecosystems accounted for 18, 35, and 47% of total precipitation inputs. The same trend exists for drainage losses over the course of the growing season (e.g., May-September). Drainage losses relative to moisture inputs were greatest between January and March, while a layer of frozen soil persisted, for both agroecosystems. Prairie drainage losses were largest between April and June following the disappearance of frost. An ecosystem's water budget, especially the downward flux of soil moisture, effects and controls numerous soil processes, probably most notable being the potential contamination threat of nitrates and other solutes leaching to our groundwater reserves.
K.R. Brye, 608-262-0415, krbrye@students.wisc.edu.
Division S-8 - Nutrient Management and Soil and Plant Analysis
Effects of Nitrogen Fertilizer Efficiency on Soil Chemical Properties. M. Avila-Segura, P. Barak, D.A. Laird, Univ. Wisconsin-Madison and USDA, ARS, NSTL.
Long-term fertility plots at Arlington, Wisconsin, show that acidification and nitrate losses associated with nitrogen fertilizer inefficiency significantly alter soil properties. Acidification has increased Mn availability to the point of toxicity in corn. Not only does CEC measured by sum of exchangeable base cations and exchangeable acidity decline with prolonged acidification, but CEC measured at fixed pH, with either Na and Ba as index cations, decreases. This may indicate permanent changes in soil exchange properties beyond simple pH-charge dependency. Analysis of soil clay also shows evidence of chemical alteration as a result of 30 yr of nitrogen fertilizer use. The effects of acidification seem to be more closely associated with quantity of N lost, particularly due to nitrate leaching, than N added.
M. Avila, 608-262-0397, mavila@students.wisc.edu.
Stable Isotope Dilution for the Determination of Selenium in Plant Samples with Inductively Coupled Plasma Mass Spectrometry. S.M. Combs and L.S. Zhang, Univ. Wisconsin-Madison/Ext.
A Se standard with enriched 77Se-isotope (77Se: 94.38%, 82Se: 0.27%) was spiked to dry plant samples (4 ng of standard to 0.5 g of sample) for the stable isotope dilution (SID) calibration method. A Se standard with natural isotope abundance was separately used for the conventional external calibration method. The samples were digested with 5 ml of HNO3+HClO4 at 150oC for 3 hours. The Se signal was measured with hydride generation ICP-MS (Zhang and Combs, J. Anal. Atom. Spectro., 11:1049, 1996). The measured 82Se/77Se ratio was used for the SID calibration and the measured 82Se signal for the external calibration. The measured Se concentrations by the two methods were in agreement with each other (160 plant samples Se = 0.016 - 0.156 or 0.034+0.017 mg kg-1. Se(SID)/Se(external) = 0.97+0.07). The measured Se concentrations in several NIST SRMs by the two calibration methods were in agreement with the certified values. Since the two methods were executed independently, they served as the backup and the tester for each other. The data quality was greatly assured.
L.S. Zhang, 608-262-4364, lzhang3facstaff.wisc.edu.
Influence of NH4-K Interactions on NO3 Leaching. J. Wu, D.A. Laird*, D.L. Karlen, P.D. Fleming, P. Barak, Iowa State Univ., USDA, ARS, NSTL, and Univ. Wisconsin-Madison.
We investigated the influence of timing and placement of NH4+ and K+fertilizer on the leaching of NO3- from soils. Treatments included control (Cont), N only (N-only), N before K (N/K), K before N (K/N), and N and K applied simultaneously (N+K). Fertilizer solutions were applied on two consecutive days by injecting 5 mL of 1.26 M NH4Cl, 0.45 M KCl, and/or H2O 2 cm below the surface in the center of each of 15 soil columns (7.7 cm diameter by 20 cm long). The columns were leached every two weeks with 200 mL of 0.001 M CaCl2, and the leachate was analyzed for NO3- and NH4+. During the latter part of the experiment (days 68 through 180) NO3- leaching for the N/K treatment was significantly different than that for the N-only treatment; and by day 180, 10% less NO3- had leached from columns receiving both NH4+ and K+fertilizer (regardless of timing) relative to the N-only columns. The results suggests that placement of K+ in the same soil volume as NH4+enhances NH4+ fixation and thereby reduced NO3- leaching.
D.A. Laird, 515-294-1581, laird@nstl.gov.
Division S-9 - Soil Mineralogy
Magnetic Susceptibility and X-Ray Absorption Studies of Ion Dispersal on Oxide Surfaces. K. Xia, W.F. Bleam*, P.A. Helmke, and F.J. Weesner, Univ. Wisconsin-Madison and Los Alamos National Laboratory.
X-ray absorption spectroscopy provide information on the structure of the adsorbed ions, while magnetic susceptibility measurement inform us about the long-range interactions and identify the onset of polynuclear clusters formation before it would be apparent in x-ray absorption spectra. Sorption of Cu(II) and Ni(II) on silica, boehmite, and titanium dioxide was studied by combining x-ray absorption spectroscopy and magnetic susceptibility measurement. The factors that control adsorbate distribution and polynuclear clusters formation of the oxide-water interface will be discussed in this paper.
Kang Xia, 608-262-0397, kxia@students.wisc.edu.
Polarized X-Ray Absorption and Magnetic Studies of Oriented Clay Films Metal Adsorption by Pillared Clay. S. Yoon* and W.F. Bleam, Univ. Wisconsin-Madison.
The purpose of our study is to determine whether Cu(II) adsorbed by zirconia-pillared smectites binds directly to the zirconia pillars, and if so, whether the adsorbed ions form clusters nucleated on the zirconia pillars. The interlayer gallery of pillared clays contains two types of sites: outer- sphere sites associated with cation substitution in the smectite layers and inner-sphere sites associated with the oxide pillars. Orientation-dependent polarized x-ray absorption fine structure (XAFS) of clay films oriented with the basal plane parallel to the x-ray polarization vector exhibits scattering from the second atomic shell that is consistent with an inner-sphere complex. Magnetic measurements of the adsorbed ion's effective magneton number suggest a paramagnetic population of adsorbed ions. Results from both XAFS and magnetic susceptibility measurements provide little evidence for clustering on zirconia pillars.
W.F. Bleam, 608-262-9956, wfbleam@facstaff.wisc.edu.
Division S-11 - Soils and Environmental Quality
Management of By-Products. L.R. Cooperband* and T.J. Logan, Univ. Wisconsin-Madison and The Ohio State Univ.
Land application of industrial, municipal and agricultural byproducts has become imperative as byproduct generation increases and landfill disposal or incineration options diminish. The objectives of this review are to identify positive and negative interactions between byproducts and the soil ecosystem and to highlight economically viable and environmentally sound uses of byproducts on land. The balance between positive and negative impacts of byproduct use depends largely on the form (raw or processed), quantity and timing of application. Agricultural use of stabilized organic byproducts like compost has been shown to improve soil physical, chemical and biological properties. Alternatively, unprocessed byproducts applied to cropland can cause either soil nutrient excesses or deficiencies. Strategies for sustainable byproduct use on land should take into account the logistics of byproducts generation, the integration of various waste streams and the creation of diverse markets for processed byproducts. Ideally, byproducts integration and processing will occur at the juncture between rural and urban zones. Such integrators will blend feedstocks to create a variety products suitable for agronomic, horticultural, land reclamation, and bioremediation uses. Current constraints to achieving efficient processing and application of byproducts include lack of end-use infrastructure to accommodate new resources, lack of economic incentives at both producer and consumer levels and lack of consumer awareness of the magnitude and current fate of byproducts.
L.R. Cooperband, 608-262-2633, lrcooperband@facstaff.wisc.edu .
Workshop - Hypoxia Around the World: Causes and Solutions
Today's Nitrogen Best Management Practices and Needed Changes. K.A. Kelling*, C.W. Rice, and S.J. Sturgul, Univ. Wisconsin-Madison and Kansas State Univ.
Best management practices for nitrogen are technically sound, economically viable and environmentally sensitive research-based recommendations that attempt to maintain farm profitability while minimizing contamination of ground- or surface-waters. Recommended practices may range from broad regional or state-wide recommendations, such as the establishment of realistic yield goals, to soil, crop or practice specific suggestions with limited applicability. The single most important N best management practice across all states is the accurate prediction of the optimum nitrogen rate to apply since any excess N decreases profitability and efficiency of N use and increases losses to unwanted parts of the environment. Most states establish a base nitrogen rate based on expected yield and a N use efficiency factor or on soil specific response data and then adjust the base rate for other nitrogen contributions such as manure, legume or irrigation water N credits or the results of N tests. The identification of the optimum N rate typically assumes that other specific crop, soil and environment nitrogen management decisions relating to source, timing, placement and use of additives will be made to minimize N losses. Increased research emphasis will continue to be placed on the development of predictive tools for correctly identifying the crop N needs correctly within a site- and management-specific context. However, while futuristic approaches such as on-the-go remote sensing and variable fertilizer applications are being developed, implementation of existing technologies such as appropriate N crediting from manure and legumes is essential. Improving farmer confidence in these credits through education, demonstration and private and public sector collaboration will enhance the process. Providing some form of insurance against the grower's personal risk associated with taking the credits may increase acceptance. More traditional suggestions include incentives for BMP adoption or regulations mandating best management.
K.A. Kelling, 608-263-2795, kkelling@facstaff.wisc.edu.
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