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2001 Agronomy Abstracts
The Soil-Plant-Atmosphere Continuum: Future Research and Farm Applications. J. NORMAN, Univ. of Wisconsin-Madison.
Test of Lagrangian Approaches and K-Theory in a Soil-Plant-Atmosphere Model. T.B. WILSON, J.M. NORMAN, and W.L. BLAND, Univ. of Wisconsin-Madison.
Is Agroecology Built on Old Ecology. W.L. BLAND, Univ. of Wisconsin-Madison.
Phosphorus Feeding and Manure Nutrient Recycling on Wisconsin Dairy Farms. J.M. POWELL, USDA-Agricultural Research Service, Dairy Forage Research Center, Madison, WI, D.B. JACKSON-SMITH, Utah State Univ., L.D. SATTER USDA-Agricultural Research Service, Dairy Forage Research Center, Madison, WI.
An Arcview Extension for Updating Field Boundaries of Agricultural Research Stations. D.H. MUELLER*, S.G. MUKHTYAR, D.L. FRYE, D.W. WIERSMA, R.F. HARRIS, S.J. VENTURA, Univ. of Wisconsin-Madison.
Tannin-Containing Forage Crops: A Way to Improve Nitrogen-Use and Profitability of Dairy Farms. J.H. GRABBER*, G.A. BRODERICK, R.E. MUCK, J.M. POWELL, M.P. RUSSELLE, D.R. MERTENS, U.S. Dairy Forage Research Center, C.A. ROTZ Pasture Systems and Watershed Management Research.
Microenvironment Effects on Bentgrass Putting Greens. W.R. KUSSOW, Univ. of Wisconsin-Madison.
Biostimulant Influences on Sand Putting Green Microbial Communities. S.R. MUELLER*, W.R. KUSSOW Univ. of Wisconsin-Madison.
Comparison of Preferential Chemical Transport at High and Low Irrigation Rates. T.J GISH*, K-J.S. KUNG, J. POSNER, G. BUBENZER, Univ. of Wisconsin-Madison, E.J. KLADIVKO, Purdue Univ., C.S. HELLING, USDA-ARS, Beltsville, MD, T.S. STEENHUIS, Cornell Univ.
Characterizing Soil Properties on a Landscape Using Multiple Data Sources at Several Scales. C.L.S. MORGAN*, K. MCSWEENEY, J. NORMAN, B. LOWERY, C. MOLLING, Univ. of Wisconsin-Madison.
X-Ray Absorption Studies of Cu(II) Binding to Humic Nitrogen Ligands. L.M. DIENER*, J.A. HOWE, P.A. HELMKE, W.F. BLEAM, Univ. of Wisconsin-Madison.
Two-Dimensional NOESY NMR Study of Neutral Organic Compounds Sorbed by Humic Acids. E.G. KIM, W.F. BLEAM,* Univ. of Wisconsin-Madison.
XAFS Study of Pb(II) Complexation by Humic Acids, the Role of Phosphate Esters and Thiols. W.F. BLEAM*, L.M. DEINER, Univ. of Wisconsin-Madison.
Binding of Metals to Humic Substances Using Donnan Membrane Equilibrium Technique. J.A. HOWE*, P.A. HELMKE, L.M. DIENER, W.F. BLEAM, Univ. of Wisconsin-Madison.
X-Ray Absorption Study of the Reaction Between Clay Minerals and the Extremely Alkaline Solutions. S. YOON*, K.G. KARTHIKEYAN, W.F. BLEAM, Univ. of Wisconsin-Madison, C.A. WEISS, U.S.A.E., J. CHOROVER, Penn State Univ.
P Utilization by Microbial Communities from High and Low P Hawaiian Soils. T.C. BALSER*, Univ. of Wisconsin-Madison, B.J. CADE-MENUN, Stanford Univ., L.P. OLANDER, Stanford Univ.
Microbial Community Composition and Nutrient Cycling in Hawaiian Tropical Soils. T.C. BALSER,* Univ. of Wisconsin-Madison, P.A. MATSON, P.M. VITOUSEK, Stanford Univ.
Effects of Papermill Residuals on Active Carbon and Available Phosphorus in Sandy Soils. C.M. NEWMAN,* L.R. COOPERBAND, Univ. of Wisconsin-Madison.
Solar Energy, and Hydrologic and Biogeochemical Cycles in Terrestrial Ecosystems Through the Ages. R.F. HARRIS*, K.J.S. KUNG, N.J. BALSTER, W.F. BLEAM, Univ. of Wisconsin-Madison.
Diversity of Polynuclear Aromatic Hydrocarbon (PAH)-Degrading Bacteria Isolated from Differing Enrichment Methods. D. VACCA*, E. KIM, W.F. BLEAM, W.J. HICKEY, Univ. of Wisconsin-Madison.
Vertical Redistribution of Phosphorus: Mining New Phosphorus Data from Old Fertility Plots. J.M. MEYER*, J.W. LYNE, M. AVILA-SEGURA, P. BARAK, Univ. of Wisconsin-Madison.
Planting Date and Hybrid Effects on Optimum Nitrogen Rates for Corn. L.G. BUNDY*, T.W. ANDRASKI, J.G. LAUER, Univ. of Wisconsin-Madison.
Geostatic Relationships Between Plant Tissue Analysis, Soil Analysis, Soil Conductivity, and Yield. J.K. CURLESS*, L.K. BINNING, J.M NORMAN, Univ. of Wisconsin-Madison.
Phosphorus Forms and Plant Availability in Soils Ammended with Organic Phosphorus Sources. A.M. EBELING*, L.G. BUNDY, Univ. of Wisconsin-Madison, J.M. POWELL, USDA-ARS.
Date of Kill Influence on Legume N Credit to Winter Wheat. P.E. SPETH*, K.A. KELLING, Univ. of Wisconsin-Madison, K. KILIAN, Univ. of Wisconsin-Platteville, T. WOOD, Lancaster Ag. Res. Stn., M. MLYNAREK, Ashland Ag. Res. Stn.
Field Estimate of Dairy Manure Nitrogen Availability to Potatoes. M.A. DAWSON*, K.A. KELLING, W.R. STEVENSON, Univ. of Wisconsin-Madison.
Influence of Fumigation on Nitrogen Needs of Potatoes. K.A. KELLING*, P.E. SPETH, D.I. ROUSE, Univ. of Wisconsin-Madison.
Using 15-N to Estimate First-Year and Residual Dairy Manure N Availability in a Field Experiment. G.R. MUNOZ*, K.A. KELLING, Univ. of Wisconsin-Madison, J.M. POWELL, U.S. Dairy Forage Res. Ctr.
15N Labeling of Dairy Manure for Nutrient Cycling Studies. J.M. POWELL*, USDA-Agricultural Research Service, Dairy Forage Research Ctr., Z. WU, Penn State Univ.
Nitrogen Tests to Predict Optimum N Rates for Winter Wheat. J.S. STUDNICKA*, T.W. ANDRASKI, L.G. BUNDY, Univ. of Wisconsin-Madison.
The Origin and Implications of the Natural Body Concept in Pedology. D.J. BROWN*, V.T. HOLLIDAY, K. MCSWEENEY, J.M. NORMAN, Univ. of Wisconsin-Madison.
The Formation of Soil-Stoneline-Ironstone-Saprolite Profiles in Uganda. D.J. BROWN*, M.K. CLAYTON, P.A. HELMKE, V.T. HOLLIDAY, K. MCSWEENEY, J.M. NORMAN, Univ. of Wisconsin-Madison.
Identifying Watershed Scale Subsurface Flow Pathways. T.J. GISH*, C.S.T. DAUGHTRY, W.P. DULANEY, C.L. WALTHALL, USDA-ARS, Beltsville, MD, K-J.S. KUNG, Univ. of Wisconsin-Madison, P. BUSS, Kenttown, Australia.
Surfactant and Biostumulant Effects on Crop Production and Nitrate Leaching. F. ARRIAGA*, B. LOWERY, Univ. of Wisconsin-Madison, C. RAMSIER, Ag Spectrum.
Phosphorus Leaching Under a Restored Tallgrass Prairie and Corn Agroecosystems. K.R. BRYE*, Univ. of Arkansas-Fayetteville, T.W. ANDRASKI, W.M. JARRELL, L.G. BUNDY, J.M. NORMAN, Univ. of Wisconsin-Madison.
Development and Evaluation of a Coupled GIS-Pesticide Modeling System. J.P. DEGROOTE*, H.S. LIN, Univ. of Wisconsin-Stevens Point, B. LOWERY, K. MCSWEENEY, Univ. of Wisconsin-Madison.
Management Practice Effects on the Potential for P Loss from Midwestern Soils. R.G. HOEFT*, L.G. BUNDY, Univ. of Wisconsin-Madison, A. MALLARINO, Iowa State Univ., INES DAVEREDE, Univ. of Illinois.
Statistical Assessment of Soil Variability from Profile Cone Penetrometer Data. A.T. WOOD*, J. ZHU, B. LOWERY, Univ. of Wisconsin-Madison.
Nitrate Leaching to Groundwater: Surfactant Use. T. NEHLS*, B. LOWERY, Univ. of Wisconsin-Madison.
Development of a Manure Testing Manual by a Multi-Regional Committee. J. PETERS*, Univ. of Wisconsin-Madison, D. BEEGLE, Penn State Univ., S. COMBS, Univ. of Wisconsin-Madison, B. HOSKINS, Univ. of Maine, J. KOVAR, Natl. Soil Tilth Lab., M. WATSON, Ohio State Univ., A. WOLF, Penn State Univ., N. WOLF, Univ. of Arkansas.
Water-Soluble Phosphorus Forms in Manure-Amended Soils. L.W. GOOD*, L.R. COOPERBAND, Univ. of Wisconsin-Madison.
Division A-3 - Agroclimatology and Agronomic Modeling
The Soil-Plant-Atmosphere Continuum: Future Research and Farm Applications . J. NORMAN, Univ. of Wisconsin-Madison.
Many research advances have been made in environmental biophysics in recent decades. Although such progress is exciting, much of this new information remains untapped for practical applications in agriculture and forestry. Agriculture is ripe for new applications of environmental biophysics because of the need to maintain productivity in the face of growing environmental regulation. Such applications are likely to involve much closer interactions with hydrologists and engineers to turn principles into practice. Is the current generation of environmental biophysicists willing and able to take on the tremendous challenge of applying state-of-the-art knowledge to on-farm management What is the desirability and what are the obstacles to more emphasis on farm applications Clearly the need for innovative models and instrumentation would not be diminished by more emphasis on applications, and the new context for basic research provided by these applications could infuse new vitality into the field.
Test of Lagrangian Approaches and K-Theory in a Soil-Plant-Atmosphere Model . T.B. WILSON, J.M. NORMAN, and W.L. BLAND, Univ. of Wisconsin-Madison.
Accurate determination of turbulence airflow within and above plant canopies is required to estimate the transfer of mass and energy in plant environments. This study examined the increasing concern that the gradient-diffusion theory (K-theory) may be unsuitable for describing turbulent transfer within plant canopies. Two recently proposed alternative methods based on Lagrangian principles (L-theory) were implemented in a soil-plant-atmosphere model (Cupid) that has used the K-theory. Model simulations were evaluated against Bowen-ratio-energy-balance measurements and temperature profiles in potato canopies. There was no difference between K- and L-theory in terms of simulating evapotranspiraton (E), sensible heat (H) and CO2 fluxes over the canopy. The model slightly underestimated measured E by 3 to 8%; the comparison of H contained much scatter and the model slightly overestimated CO2 flux. When the model was tested by simulating temperature and vapor pressure profiles within the canopy, the difference between the K- and L-theory was much smaller than the difference between each theory and the measurements. From simulated temperature profiles, the near-field correction provided by using L-theory seemed to be significant in canopies where the foliage is concentrated in the upper part, but appeared unnecessary for foliage distributed throughout the canopy depth.
Division A-8 - Integrated Agricultural Systems
Is Agroecology Built on Old Ecology . W.L. BLAND, Univ. of Wisconsin-Madison.
The rhetoric of agroecology appeals strongly to the "balance of nature" myth. It is important to reflect on underlying mythology and metaphors because they exert powerful influences in many fields of science, including ecology. Balance of nature concepts were articulated by classical philosophers, and continued to strongly influence ecology until very recently. At a finer timescale of decades, ecology passes from "old" to "new" formulations, a process of self-reflection that agroecology does not exhibit. If the goal of agroecology is to bring ecological concepts to bear on agriculture, aggressive pursuit of emerging concepts appears essential. Ideas surrounding selforganization and causality may apply to cropping systems. The potential for multiple stable states and historical contingency in system behavior may have relevance for crop-pest dynamics. A core principle of conventional agriculture is reducing the probability of undesirable outcomes; agroecology should address risk concepts. Agroecology properly attacks the myths underlying conventional agriculture, but should be wary of failing to reflect on and renew its own key metaphors and myths.
Phosphorus Feeding and Manure Nutrient Recycling on Wisconsin Dairy Farms . J.M. POWELL, USDA-Agricultural Research Service, Dairy Forage Research Center, Madison, WI, D.B. JACKSON-SMITH, Utah State Univ., L.D. SATTER USDA-Agricultural Research Service, Dairy Forage Research Center, Madison, WI.
Nutrient management regulations for livestock operations focus on a farm's ability to recycle manure phosphorus (P) through crops. Little is known about relationships between feeding practices and manure P levels on dairy farms, or between herd size, cropland area and a farm's ability to recycle manure P. A survey of 98 representative dairy farms in Wisconsin showed that over half of the farms were self-sufficient in forage (alfalfa, corn silage) and grain production. Lactating dairy cows derived 90% of their feed dry matter (DM) and 78% of their P intake from these homegrown feeds. The P content of the dairy diet ranged from 2.3 to 8.5 with an average of 4.0 g P/kg. Approximately 85% of the surveyed dairy farms fed P in excess of the recently updated National Research Council (NRC) recommendations. There was a good relationship between dietary P and manure P. Stocking rates ranged from 0.3 to 2.6 cows/ha. Farms having stocking rates of less than 1.1 cows/ha were self-sufficient in feed production. Approximately 40% of the farms have a positive P balance (manure P exceeds harvested crop P). On these farms, lowering dietary P to NRCrecommended levels would reduce the number of farms having a positive P balance and the amount of land in positive P balance by two-thirds.
An Arcview Extension for Updating Field Boundaries of Agricultural Research Stations . D.H. MUELLER*, S.G. MUKHTYAR, D.L. FRYE, D.W. WIERSMA, R.F. HARRIS, S.J. VENTURA, Univ. of Wisconsin-Madison.
The Arlington Agricultural Research Station (ARS) is the prototype for application of the Wisconsin ARS GIS to management of a historically well established research station. The Arlington ARS GIS is composed of spatial data maintained within ArcView GIS software and field records maintained within MS Access. A customized ArcView extension provides a tool within ArcView for carrying out station management. It has great flexibility in creating and updating field boundaries and in displaying field records. Specifically, the extension allows the user to draw a new field boundary, add a new field boundary by importing GPS coordinates, copy a field boundary from another shapefile, edit an existing field boundary and add tabular data to a shapefile, join tables in MS Access and Arcview, and compose and print maps. Staff at ARS have applied the extension to laying out research plots, and to creating a spatially referenced primary field boundaries map and an annual land use map showing sub-sections of fields. Maps have also been created to help plan for field days and for filing a crop report for the Farm Service Agency.
Tannin-Containing Forage Crops: A Way to Improve Nitrogen-Use and Profitability of Dairy Farms . J.H. GRABBER*, G.A. BRODERICK, R.E. MUCK, J.M. POWELL, M.P. RUSSELLE, D.R. MERTENS, U.S. Dairy Forage Research Center, C.A. ROTZ Pasture Systems and Watershed Management Research.
Plant breeding and biotechnology efforts are underway in the U.S. and abroad to develop alfalfa and other forages with modest amounts of condensed tannins. Tannins bind to proteins, potentially altering N availability in forages during ensiling, ruminal digestion, and soil mineralization. We used a dairy-forage simulation model (DAFOSYM) to predict the impact of growing and feeding an alfalfa with 1 to 2% tannin on a dairy farm in southern Wisconsin with 100 cows, 85 heifers, and 100 ha of silt loam soil. Alfalfa silage and corn silage were produced and fed in ratios of 2:1 or 1:2. Crop yields were similar when normal or tannin-containing alfalfa were grown. Feeding tannin-containing alfalfa reduced farm N losses by 20 to 30%, increased milk production by 1.5 to 3%, and increased farm profitability by $9,500 to $15,600 per year. Benefits were greatest in alfalfa-dominant production systems. Feeding tannin-containing alfalfa shifted grain supplementation from soybeans to corn, reducing the need for off-site production of potentially erosive and nitrate leaky row-crops by about 60%. Our current studies are aimed at identifying optimal tannin concentrations and management practices for enhancing protein and N-use on dairy farms.
Division C5 - Turfgrass Science
Microenvironment Effects on Bentgrass Putting Greens . W.R. KUSSOW, Univ. of Wisconsin-Madison.
Shading and restricted air flow cause deterioration in putting green quality. The purpose of this study was to establish how adverse microenvironments lead to declines in putting green quality and to test the mitigating effects of select cultural practices and putting green root zone mix composition. A shade-air flow restriction gradient was imposed on 10 putting greens differing in root zone mix composition. Over 2 yr, putting green quality has declined an average of 70% when comparing a full-sun, no air flow obstruction microenvironment to one with 67% shade and 58% less air movement. Factors primarily responsible for this quality reduction have been disease severity and reduced traffic tolerance resulting from a 47% increase in bentgrass shoot growth rate in combination with a 19% increase in shoot moisture content. Application of trinexapac-ethyl (Primo) to slow shoot growth or use of low moisture retaining root zone material during construction have had no significant effects on the declines in putting green quality.
Biostimulant Influences on Sand Putting Green Microbial Communities . S.R. MUELLER*, W.R. KUSSOW Univ. of Wisconsin-Madison.
Although there is growing evidence that sand putting greens do in fact sustain active and diverse microbial populations, products designed to overcome perceived deficiencies in this regard abound in the marketplace. The purpose of this study was to observe the influences of five such products on creeping bentgrass quality and the soil microbial community. The products were applied per manufacturer specifications to a 3-yr-old 'SR 1119' creeping bentgrass populated sand-peat humus root zone mix putting green. The turf was visually rated bi-weekly for three quality characteristics and soil samples removed for analysis. Treatment effects on microbial activity, functional diversity, and population composition were characterized by way of assays for four enzymes, the Biolog technique and phospholipid fatty acid analysis. Small but occasionally significant treatment effects on turf quality were observed. These differences appear to have resulted from differences in turfgrass tissue N status. Treatment effects on soil microbial activity and diversity and the possible relationships to turf quality will be discussed.
Division S-1 - Soil Physics
Comparison of Preferential Chemical Transport at High and Low Irrigation Rates . T.J GISH*, K-J.S. KUNG, J. POSNER, G. BUBENZER, Univ. of Wisconsin-Madison, E.J. KLADIVKO, Purdue Univ., C.S. HELLING, USDA-ARS, Beltsville, MD, T.S. STEENHUIS, Cornell Univ.
Without flux information, the variability of matrix and preferential flow processes makes scientific interpretation of chemical transport uncertain and development of effective non-point source legislation nearly impossible. Chemical fluxes of bromide (Br; 280 kg/ha) and penta-fluorobenzoic acid (PFBA; 121 kg/ha) were evaluated at two irrigation rates (3.1 mm/h and 0.89 mm/h) under near steady state conditions at the Univ. of Wisconsin, Madison. Tracers were applied to a 3.5m x 24m region parallel to and offset 0.3m from a tile drain. At an irrigation rate of 3.1 mm/h nearly 20% of the applied Br was recovered in the tile line after 80 mm of irrigation, although an estimated pore volume is about 350mm of water. On the other hand, at an irrigation rate of 0.89 mm/h only 0.32% of the applied PFBA was lost through leaching after 80 mm of irrigation. The rapid appearance of Br and the large quantities leached with small water inputs suggest a flow process dominated by preferential flow, while the main PFBA breakthrough pattern fitted< the 1-D convective-dispersive transport well, suggesting that the PFBA transport was dominated by matrix flow. This study suggests that there may be a critical water flux whereby preferential flow is initiated and subsequently dominates chemical transport through soil.
Characterizing Soil Properties on a Landscape Using Multiple Data Sources at Several Scales . C.L.S. MORGAN*, K. MCSWEENEY, J. NORMAN, B. LOWERY, C. MOLLING, Univ. of Wisconsin-Madison.
Precision agriculture modeling systems that calculate horizontal and vertical water movement across the landscape require information on soil hydraulic properties at high spatial resolution in three-dimensions. Soil profile properties are mapped for a production agriculture landscape (40-80 ha) on a ten-meter grid using multiple data sources at different scales. These data sources include hand sampling for texture, horizon thickness, and water at field capacity (16-20 locations), an USGS soil map, soil electrical conductivity maps (10m resolution), elevation maps (10m resolution), and geostatistics. The quality of the soil maps using these different methods are evaluated and compared.
Division S-2 - Soil Chemistry
X-Ray Absorption Studies of Cu(II) Binding to Humic Nitrogen Ligands . L.M. DIENER*, J.A. HOWE, P.A. HELMKE, W.F. BLEAM, Univ. of Wisconsin-Madison.
X-ray absorption near edge structure (XANES) at the nitrogen K-edge of a soil humic acid (1R106H, International Humic Substance Society) reveals two dominant nitrogen forms, probably amine and aromatic heterocyclic nitrogen< (pyrimidines and purines). By comparing nitrogen XANES spectra of humic acid samples with and without Cu(II), we can determine whether a significant proportion of the humic amine ligands bind this metal ion. X-ray absorption fine structure (XAFS) spectra collected at the copper K-edge reveal no significant differences in the binding environment when comparing metal-ion loading at a Cu:N ratio of 1:1 with a much higher loading, far exceeding the humic nitrogen content, just below the total metal binding capacity of the humic acid where oxygen ligands dominate.
Two-Dimensional NOESY NMR Study of Neutral Organic Compounds Sorbed by Humic Acids. E.G. KIM, W.F. BLEAM,* Univ. of Wisconsin-Madison.
Two-dimensional homonuclear H-1 nuclear Overhauser effect spectroscopy (NOESY) studies reveal the pH dependent conformation of humic acids extracted from two Wisconsin soils, the Wacousta (fine-silty, mixed, mesic Typic Endoaquolls) and the Houghton (euic, mesic Typic Medisaprists), are fundamentally identical with that previously reported for humic acids extracted from another Wisconsin soil, the Sparta (uncoated, mesic Typic Quartzipsamments): humic aliphatic structures adopt a folded conformation below pH 9 while humic aromatic structures appear to remain extended. NOESY spectra show benzene and n-octane co-solubilized within humic micelles are confined within folded humic aliphatic structures and reside in unusually close proximity to one another. Apparently humic macromolecular micelles have sufficient volume to hold numerous benzene.
XAFS Study of Pb(II) Complexation by Humic Acids, the Role of Phosphate Esters and Thiols. W.F. BLEAM*, L.M. DEINER, Univ. of Wisconsin-Madison.
X-ray absorption near edge structure (XANES) at the sulfur K-edge of humic acids extracted from a Wisconsin soil, the Houghton muck (euic, mesic Typic Medisaprists) reveals the various oxidation states of humic sulfur. Quantitative fitting of the humic sulfur XANES spectra allowed us to determine the reduced sulfur content, probably dominated by thiol ligands. The humic thiol content slighlty exceeds the humic phosphate ester content; as a consequence samples prepared with a Pb:reduced-sulfur ratio of 1:1 would slightly exceed a Pb:phosphateester ratio of 1:1. X-ray absorption fine structure (XAFS) spectra collected at the lead L-edge permits us to determine whether humic thiol or phosphate-ester ligands contribute to the binding of Pb(II) by humic acids. The bond lengths and coordination number distinguish between oxygen and sulfur in the first coordination sphere while the presence of phosphorus in the second coordination sphere indicates the involvement of phosphate.
Binding of Metals to Humic Substances Using Donnan Membrane Equilibrium Technique. J.A. HOWE*, P.A. HELMKE, L.M. DIENER, W.F. BLEAM, Univ. of Wisconsin-Madison.
Binding of copper to dissolved soil fulvic acid was investigated using the Donnan membrane equilibrium technique. A soil II fulvic acid standard from the International Humic Substances Society was used. Ultrapure copper nitrate was added to the fulvic acid samples (100 mg L[superscript -1]) at a wide range of copper concentrations (0.1 to 17 mg L[superscript -1]) at pH 3.7. Free copper was separated using the Donnan membrane technique and then determined by graphite furnace atomic absorption spectroscopy. The Cu-fulvic acid samples were analyzed by nitrogen and oxygen XANES. The results indicate that complexation of copper by fulvic acid occurred at more than one binding site.
X-Ray Absorption Study of the Reaction Between Clay Minerals and the Extremely Alkaline Solutions. S. YOON*, K.G. KARTHIKEYAN, W.F. BLEAM, Univ. of Wisconsin-Madison, C.A. WEISS, U.S.A.E., J. CHOROVER, Penn State Univ.
To examine the reaction between REDOX/PUREX tank waste (a highly alkaline solution) and clay minerals from soil at the Hanford DOE site, we exposed a hectorite (SHCa-1, Clay Mineral Society) to a simulated REDOX/PUREX solution and observed the products using both Si-29 cross-polarization magic-angle spinning (CPMAS) solid-state nuclear magnetic resonance (NMR) and germanium K-edge x-ray absorption fine structure (XAFS). The Si-29 CPMAS NMR results indicate the hectorite dissolves congruently in the early stages of the reaction as it releases dissolved silica. We added trace amounts of germanate to the simulated REDOX/PUREX solution, allowing added germanate to become incorporated in any aluminosilicate precipitates that may form as a product of the reaction. The hectorite initially contains sufficient native germanate to identify the original reactant. Sufficient added germanate becomes incorporated to reveal the formation of a distinct, but as yet not fully characterized secondary aluminosilicate precipitate.
Division S-3 - Soil Biology and Biochemistry
P Utilization by Microbial Communities from High and Low P Hawaiian Soils. T.C. BALSER*, Univ. of Wisconsin-Madison, B.J. CADE-MENUN, Stanford Univ., L.P. OLANDER, Stanford Univ.
Microbial P utilization can depend on both the P forms available and on the microbial community. For this study, our objective was to trace the flow and fate of added P, and how different microbial communities partition P when it is limiting, or in excess. We used soils from a Hawaiian chronosequence to examine microbial utilization of P in high and low P mixed lab cultures. Soils from 2 sites, one high in P (fertile) and one low in P (P-limited), were used to inoculate high and low P media. Cultures were sampled 0, 1, 2, 4, and 7 days after inoculation. Samples were collected to measure 1) 3 P enzymes: acid phosphomonoesterase, alkaline phosphomonoesterase and diesterase; 2) 31P-NMR; and 3) microbial community composition, biomass; 4) total P, C and N. Results show differing microbial response to the high and low P in the medium. For example, the community from the P-limited soil, in the low P medium, was dominated by fungi. The community from the fertile soil was dominated by bacteria. Activities of all three enzymes increased over time, and varied by soil and P treatment. Acid phosphomonoesterase activity differed by soil, with higher activity from the P-limited soil. Diesterase activity differed by P treatment, with more activity in the low P medium, regardless of soil.
Microbial Community Composition and Nutrient Cycling in Hawaiian Tropical Soils. T.C. BALSER,* Univ. of Wisconsin-Madison, P.A. MATSON, P.M. VITOUSEK, Stanford Univ.
We measured soil properties (N availability, pH, and soil C, N, P), and microbial community composition and metabolic activity (phospholipid fatty acid analysis, substrate utilization profile), at several natural and fertilized forest sites along an age sequence in the Hawaiian Islands. We asked whether fertilization with nitrogen (N) and phosphorus (P) affects microbial community composition and metabolic activity in the same way that a natural gradient in N and P availability does. The sites show a distinct patterns in soil properties with age, and have distinguishable microbial communities. Soils at the natural sites range in age from 300 to 4.1 million years old. Intermediate aged sites have maximal soil N and P content, and also have the highest microbial biomass and metabolic activity. Microbial community fatty acid profiles from the youngest (300 year old), intermediate (20,000 year old), and oldest (4.1 million year old) sites differ significantly (principal components analysis). Long-term application of nitrogen and phosphorus fertilizer has affected microbial community composition, as well as community substrate utilization profiles. Changes in N availability (both natural and fertilizer) appear to be related to changes in microbial community parameters, whereas changes in P availability had less impact.
Effects of Papermill Residuals on Active Carbon and Available Phosphorus in Sandy Soils. C.M. NEWMAN,* L.R. COOPERBAND, Univ. of Wisconsin-Madison.
The use of paper mill sludge (PS) in vegetable production could increase the active soil carbon pools, specifically particulate organic carbon, (POM-C), >53 mm. This study looked at three years, 1998-2000, of annual PS, PS compost (PSC), PS and bark compost (PSB), and a one-time peat carbon control applications in a potato- snap bean-cucumber rotation. Composite soil samples were taken from each plot three times per growing season: pre-amendment, midseason during crop growth, and post harvest. Fractionation was performed by first sieving soil through a 6.3 mm sieve and then shaking samples for 16 hours with water and glass beads. Then soil was washed with water over a >53 mm sieve. What remained on the sieve, the POM-C and sand, was then oven dried at 50 oC, ground, and analyzed for total C by total combustion. POM-C can be an indicator of the biological activity in the soil, and may be linked with the occurrence of crop diseases, and the formation of stable soil aggregates.
Solar Energy, and Hydrologic and Biogeochemical Cycles in Terrestrial Ecosystems Through the Ages. R.F. HARRIS*, K.J.S. KUNG, N.J. BALSTER, W.F. BLEAM, Univ. of Wisconsin-Madison.
A soil life-oriented view of solar energy, hydrologic and biogeochemical cycles in terrestrial ecosystems through the ages is presented as a function of instruction applications of simplified and advanced versions of core diagrams, tables and supporting photo and cartoon images. Evolutionary times focus on the global anoxygenic and oxygenic biotic (from start to current) phases. Biogeochemical cycles for each time phase include an interlinked 1) trophic organism flow diagram composed of ecophysiological groups (photo/chemo, auto/hetero, litho/organo, obligate aerobe/facultative anaerobe/ obligate anaerobe), food chain groups (producer/consumer/decomposer), and biogeochemical groups (specific inorganic and organic electron donor oxidizers and electron acceptor reducers); 2) classification table of representative phenotypic and phylogenetic organisms; 3) equation table of representative dissimilitary and assimilatory reactions (including redox and energy characteristics) for each of the C, H, O, N, P, S, Fe, Mn and other micro elements; and 4) redox-based biogeochemical cycle diagram for each of the elements.
Diversity of Polynuclear Aromatic Hydrocarbon (PAH)-Degrading Bacteria Isolated from Differing Enrichment Methods. D. VACCA*, E. KIM, W.F. BLEAM, W.J. HICKEY, Univ. of Wisconsin-Madison.
We investigated the diversity of PAH-degrading bacteria isolated from PAH-contaminated soil by using the standard enrichment technique (PAH added as pure crystals) and from enrichments in which the PAH was sorbed to a nylon filter. The standard approach yielded 14 isolates confirmed as PAH degrading bacteria. Sequence analysis of 16S rRNA genes indicated Sphingomonas and Mycobacterium were the most frequently recovered organisms and represented by five and six isolates, respectively. Other isolates were identified as Pseudomonas, Xanthobacter, and ultramicrobacteria. Two pure cultures were obtained from the sorbed PAH enrichments, and were identified as Sphingomonas and ultramicrobacterium. Nine isolates had unique genomic fingerprints as determined by repetitive element PCR, suggesting each was a distinct genomospecies. All three isolates identified as ultramicrobacteria had a common genomic fingerprint; four sphingomonads also shared a common banding pattern. Our results indicate sphingomonads are a potentially important group of PAH degrading bacteria and significant subspecies diversity may exist within populations of PAH-degrading sphingomonads at a single PAH contaminated location.
Division S-4 - Soil Fertility and Plant Nutrition
Vertical Redistribution of Phosphorus: Mining New Phosphorus Data from Old Fertility Plots. J.M. MEYER*, J.W. LYNE, M. AVILA-SEGURA, P. BARAK, Univ. of Wisconsin-Madison.
Since the question of the fate of agricultural phosphorus in the environment is most properly the long term effect of a particular phosphorus-management practice, pertinent information must be extracted from long-term experiments that were established for other purposes. A set of fertility plots established in 1962 at the UW Agricultural Research Station at Arlington, WI, included addition of dairy manure at a rate of 15 ton/acre/yr for 32 years and addition of phosphorus fertilizer for 20 years. The plots and treatments were re-marked and a number of soil cores to a depth of 1-m representing treatments of interest. HF-extractable P levels in the 20-cm plow layer show clear differences between those cores amended with mineral P fertilizers and with P-containing dairy manure, presumably reflecting P loading rates. However, the pattern of P distribution with depth below the plow layer is striking, with manured soil behaving like a chromatographic column, with available-P enriched as much as 20-cm below the plow layer, whereas the mineral- P treatment affects a depth of only 5 cm or less below the plow layer. Further work is underway to "mine" information about the long-term fate of phosphorus in a Wisconsin soil from this long-term experiment.
Planting Date and Hybrid Effects on Optimum Nitrogen Rates for Corn. L.G. BUNDY*, T.W. ANDRASKI, J.G. LAUER, Univ. of Wisconsin-Madison.
Corn planting is sometimes delayed by weather conditions or changes in cropping plans. This 3-yr study was conducted to evaluate planting date (PD) and relative maturity (RM) effects on optimum N rates for grain and silage production and to evaluate soil nitrate test performance under these conditions. Main plot treatments were four PD (May 1 and June 1, 10, and 20) in a randomized complete block design with four replications. Main plots were split for two hybrid RM (100- and 90-day) and six N rates (0 to 224 kg N/ha). Soil samples for nitrate tests were collected from the 0 kg N/ha treatment for each hybrid and PD. Grain yields usually decreased with later PD and were increased by applied N in all years. Hybrid RM effects on yields were significant in two of the three years, but these responses were influenced by PD in all years. Optimum N rates for grain ranged from 78 to 157 kg N/ha and did not differ among PD. Optimum N rates for silage ranged from 0 to108 kg N/ha across years and differed among PD only in one year. Preplant and presidedress soil nitrate tests provided improved identification of optimum N rates and increased economic return by $5 to $35/ha. Corn N application rates do not require adjustment for PD or hybrid RM. Nitrogen applications based on soil nitrate tests reduced excess N additions by 17 to 101 kg N/ha.
Geostatic Relationships Between Plant Tissue Analysis, Soil Analysis, Soil Conductivity, and Yield. J.K. CURLESS*, L.K. BINNING, J.M NORMAN, Univ. of Wisconsin-Madison.
The ability to predict fertility concentrations and its spatial distribution provides valuable information for managing fertility and yield variations within agricultural fields. To gain an understanding of plant and soil nutrient variability and how they influence (Zea mays) and (Glycine max ) yields, a research study was conducted on a dry land production field in Northern Illinois. Research began in 1998 and continued through 2000 growing season near Shabbona, Illinois a 25 ha production field. A soil-sampling grid of 0.068 ha was established in 1998 on the production site. The grid assignment continued for the duration of the study for plant and soil samplings. Geostatical methods were used to analyze the dynamics of plant tissue, soil samples, soil conductivity, and yield for each season via spatial regression using S-Plus®. The analysis conducted proved to be a useful tool in detecting spatial variability of soil fertility concentrations and their influences on yield productivity.
Phosphorus Forms and Plant Availability in Soils Ammended with Organic Phosphorus Sources . A.M. EBELING*, L.G. BUNDY, Univ. of Wisconsin-Madison, J.M. POWELL, USDA-ARS.
Land-applied organic wastes can lead to accumulation of phosphorus(P) in soil and can contribute to nonpoint source pollution of surface waters. The objective of this study was to investigate soil test P changes due to various P sources in an incubation study and to determine plant available P from the same P sources in a greenhouse study. The P sources were whole(W), fiber(F), low(L), medium(M), and high(H) P manures, biosolids(B), and calcium phosphate(CP) applied at rates of 0, 101, 202, and 404 kg P/ha to a silt loam soil and incubated at 21C. Five soil samplings were taken at 16-wk intervals and analyzed for deionized water, Mehlich 3, Bray-Kurtz P1, ammonium oxalate extractable P, P saturation, bioavailable P, and anion exchange membrane extractable P. Similar P treatments were applied to sand or sand+soil cultures, and a wheat test crop was harvested and analyzed for total P. In general, L and F supplied the least available P, CP the most, and M, H, W, and B contributed intermediate amounts of P as analyzed by the soil P tests. Agronomic and environmental P tests were strongly correlated. In sand, P sources increased P uptake in the order L,W,F,CP,H,M,B, but increased in sand+soil in the order CP,F,B,W,L,M,H. Results of the greenhouse study indicate that organic P mineralization and reaction of soluble P with soil constituents mask initial differences in P sources.
Date of Kill Influence on Legume N Credit to Winter Wheat. P.E. SPETH*, K.A. KELLING, Univ. of Wisconsin-Madison, K. KILIAN, Univ. of Wisconsin-Platteville, T. WOOD, Lancaster Ag. Res. Stn., M. MLYNAREK, Ashland Ag. Res. Stn.
For legumes to be effective N sources for succeeding crops, they must supply sufficient N in a timely manner to meet crop demand. This field experiment examined the effect of killing alfalfa following second cut (early to mid-Aug) or following third cut (early to mid-Sep) on the available N supply to winter wheat planted no-till or following moldboard plowing. These split- split plot experiments at three locations over 2 yr used kill date (Aug or Sep) as the main plot, tillage system (no-till or moldboard) as the first split and N fertilizer rate (0 to 101 kg/ha) as the final split. Although the effects of N rate and tillage were apparent in most site years (increased lodging and decreased yields with plowing and higher N rates), time of alfalfa kill was significant only at the location with high soil organic matter (approx. 40 g/kg). At this location, killing the alfalfa earlier decreased yield and increased lodging (average of 0.45 Mg/ha and 24.7%, respectively) even when the wheat was planted no-till and no N fertilizer as applied. Moldboard plowing and adding N fertilizer generally exacerbated the problem. These results suggest that sacrificing the final alfalfa harvest is not necessary for ensuring adequate legume N to the wheat.
Field Estimate of Dairy Manure Nitrogen Availability to Potatoes. M.A. DAWSON*, K.A. KELLING, W.R. STEVENSON, Univ. of Wisconsin-Madison.
Within Wisconsin, there is a distinct movement toward dairy herd expansion and consolidation of small farms. With the increase in manure production, these large dairies are considering various land and manure management arrangements with non-livestock farmers, such as potato producers. The purpose of this study is to evaluate several potato production issues resulting from such partnerships including the availability of dairy manure nutrients to potatoes. Nitrogen and phosphorus availability were evaluated in field experiments conducted in northeast Wisconsin using a moderate and a high liquid dairy manure rate (93,500 and 187,000L/ha) compared with results obtained from nitrogen or phosphate fertilizer applied at five rates (0 to 269kg/ha). Tuber yield and nitrogen uptake responses from the low rate of manure showed availability of about 20% of the applied manurial N. Phosphorous availability was not measurable as P responses were minimal. The responses at the high rate of manure exceeded any obtained with the applied fertilizers. A companion study showed that the potatoes tended to yield better when all of the nutrients were supplied from manure than when an estimated equivalent amount was applied as fertilizer. Our preliminary data show yield, grade, and size advantages when manure was included in the system, and few other production problems were evident.
Influence of Fumigation on Nitrogen Needs of Potatoes . K.A. KELLING*, P.E. SPETH, D.I. ROUSE, Univ. of Wisconsin-Madison.
Soil fumigation with metam-sodium is frequently used to control Verticillium in potatoes. This 3-yr field study examined the interaction of fumigation on optimal N rate and N sources for Russet Burbank on the irrigated sands of central Wisconsin. The split-plot trials used fumigation (none, spring, or fall) and N rate (0, 67, 134 or 202 kg N/ha) or fumigation and N source (ammonium sulfate, ammonium nitrate, or urea) as the splits. Fumigation resulted in yield increases averaging 41 Mg/ha; however, the fumigation x N rate interaction term was not significant with the magnitude of the N response from 0 to the high N rate about the same with and without fumigation. Disease ratings for early dying also showed independent and additive effects from both fumigation and N rate with severity rating of 79 for zero N without fumigation to 31 for 202 kg N/ha with fumigation. Responses were similar for fall and spring fumigations. Nitrogen source had no impact on tuber yield or quality even where the fumigant was spring applied and all of the N as ammoniacal. This study does not support the hypothesis that the increased yield potential associated with fumigation increases the optimum N rate or that spring fumigation paired with an ammoniacal N source is a problem.
Using 15-N to Estimate First-Year and Residual Dairy Manure N Availability in a Field Experiment. G.R. MUNOZ*, K.A. KELLING, Univ. of Wisconsin-Madison, J.M. POWELL, U.S. Dairy Forage Res. Ctr.
Estimates of manure N availability can be determined by a variety of methods, including measuring apparent N recovery, comparison of response with fertilizer treatments (fertilizer equivalent), or by direct measure using the stable 15-N isotope. This field experiment compared results from these methods over a 3-yr period where manure was applied to new plots every year and to the same plots each year. First-year N availability as directly measured by 15-N averaged 16% and was generally lower than the estimates using other methods (28 and 35%, respectively). However, individual measurements by 15-N showed much less variation within years or between years. The lower values associated with the direct measurement is likely due to the unaccounted for turnover of labeled N with labile soil N. Residual availability as determined by 15-N was 4 to 9% of the original application in Year 2 and 2 to 5% for Year 3. Estimates using the other techniques were generally similar, but again more variable and sometimes not possible due to high uptake by the controls. These data show that while 15-N measurements of manure N availability are useful and less variable, they may underestimate the total amount of N available to the plant.
15N Labeling of Dairy Manure for Nutrient Cycling Studies. J.M. POWELL*, USDA-Agricultural Research Service, Dairy Forage Research Ctr., Z. WU, Penn State Univ.
Most dairy farmers do not credit the nutrients contained in manure. The lack of manure nitrogen (N) crediting may be due to many factors that make manure an undependable source of plant N, including the inherent shortcomings of the classical, indirect methods used to estimate manure N availability to crops. Dairy manure was enriched in the stable isotope 15N to make direct measurements of manure N uptake by crops. Two labeling methods were used: (1) the organic method involved 15N enrichment of alfalfa and corn silage and subsequent feeding of these forages to dairy cows during each of 4 years using an 8-day feed and manure collection period per year and (2) the inorganic method involved feeding 15N-enriched urea during each of 2 years using an 8-day feed and manure collection period per year. The organic method labeled urine N, fecal microbial N, and fecal undigested feed N. The inorganic method labeled only urine N and fecal microbial N. We compared the two labeling techniques in terms of their pattern of 15N excretion and the mineralization and plant uptake of labeled manure N in soil/manure incubations, a greenhouse trial and field plot trials. The costs and benefits associated with labeling manure N components for short-term (one cropping season) or long-term nutrient cycling studies are discussed.
Nitrogen Tests to Predict Optimum N Rates for Winter Wheat. J.S. STUDNICKA*, T.W. ANDRASKI, L.G. BUNDY, Univ. of Wisconsin-Madison.
Nitrogen (N) tests have potential for identifying optimum N rates in cropping systems. This study evaluated several N tests for site-specific prediction of optimum N rates for winter wheat (Triticum aestivum L.). Wheat response to applied N (0 to 202 kg/ha) was determined in a 4-yr study with four sites each year on medium-or fine-textured soils. Nitrogen tests included soil nitrate determinations, UV absorbance of sodium bicarbonate soil extracts, plant N concentration and uptake, and chlorophyll meter measurements. Economic optimum N rates (EONR) for each site-year were determined for typical wheat and N prices using regression analysis of wheat N response data. Wheat yields at optimum N rates ranged from 2.89 to 5.78 Mg/ha depending on year and location. Preplant soil nitrate content had the strongest relationship with winter wheat N response and with EONR. Over-application of N fertilizer increased lodging and reduced test weight, thus having the same negative effect on economic returns as use of below-optimum N rates. Results from this study were used to develop improved N recommendations for winter wheat in Wisconsin. Nitrogen recommendations based on the preplant nitrate test help avoid reduced profits, yield reductions, and environmental risk due to over-fertilization.
Division S-5 - Pedology
The Origin and Implications of the Natural Body Concept in Pedology . D.J. BROWN*, V.T. HOLLIDAY, K. MCSWEENEY, J.M. NORMAN, Univ. of Wisconsin-Madison.
Pedologists claim to study "soil as a natural body," yet few fully understand the meaning of this concept. In brief, the natural body concept applies a biological metaphor to the study of soil profiles, what is referred to more generally as "organicism." This idea from the 19th century carries both complexity of meaning and significant modern implications. The soil classification system, the "pedon" definition, soil judging contests, and terminology like "soil genesis" are all artifacts of the biological metaphor. Historically, organicism has been applied in many ways for differing reasons to varied fields. Prominent examples from the late 19th and early 20th century include Davisian geomorphology, Clementian plant ecology, Wheeler's zoology, and Spencer's sociology. The justification for studying soil as natural body came mainly from Humboldt's geography, but the concept proved very useful both intellectually as an organizing framework for soil surveys and research, and politically to separate pedology from geology. With a better understanding of the historical origin, rationale, and utility of the natural body concept underlying pedology even today, we can reflect critically on the intellectual and political utility of the concept as a guide to future development in pedology.
The Formation of Soil-Stoneline-Ironstone-Saprolite Profiles in Uganda. D.J. BROWN*, M.K. CLAYTON, P.A. HELMKE, V.T. HOLLIDAY, K. MCSWEENEY, J.M. NORMAN, Univ. of Wisconsin-Madison.
On upland areas in central Uganda, we commonly found a soil, stoneline, saprolite sequence progressing downward from the surface; with or without significant ironstone nodules in the stoneline, sometimes terminating in a layer of continuous ironstone. Field observations suggest that these profiles formed originally as stream beds on valley floors, which were later covered by sediments and "raised" through landscape inversion. We test this theory with a twopronged approach employing: (1) spatial statistics to analyze stone line patterns; and (2) geochemical analysis of Fe, K, Na and several trace elements. Through neutron activation analysis, we have discovered high K concentrations (largely non-exchangeable) and a remarkably consistent K/Na ratio for soils sampled in our study area, pointing to a significant (and surprising) K-feldspar presence. Using Sc and Th as stable elements, K as a Feldspar proxy, and Hf as a zircon proxy, we then analyze a suite of indicator ratios involving Fe, K, and the rare earths for insights into progeny and weathering processes for the different profile components. This information allows us to better understand, explain and predict the spatial patterns found on the landscape.
Identifying Watershed Scale Subsurface Flow Pathways . T.J. GISH*, C.S.T. DAUGHTRY, W.P. DULANEY, C.L. WALTHALL, USDA-ARS, Beltsville, MD, K-J.S. KUNG, Univ. of Wisconsin-Madison, P. BUSS, Kenttown, Australia.
Fundamental watershed-scale hydrologic processes governing chemical transport through soil to neighboring ecosystems are so poorly understood that strategies for mitigating chemical contamination cannot be accurately formulated. The major limitation to quantifying chemical transport at the field and watershed scale is an accurate characterization of the subsurface flow processes, including preferential flow. Ground-penetrating radar data was used to identify the subsurface convergent flow pathways on four small watersheds, USDA-ARS, BARC. The spatial distribution of corn grain yields, remote sensing, real-time soil moisture monitoring, and surface soil cores were used to evaluate and confirm the location of the GPR-identified flow pathways. Soil moisture observations near the GPRidentified flow pathways support the existence of funnel flow. Under water-limiting conditions high corn grain producing regions were poorly correlated with surface soil texture, organic matter, P and K spatial concentration distributions. However, superimposition of the subsurface convergent flow pathways with the high yielding corn regions on a CIR image suggest that funnel flow processes do influence yield. As a result, a sampling strategy based primarily on ground-penetrating radar may be useful in identifying subsurface convergent flow pathways.
Division S-6 - Soil and Water Management and Conservation
Surfactant and Biostumulant Effects on Crop Production and Nitrate Leaching. F. ARRIAGA*, B. LOWERY, Univ. of Wisconsin-Madison, C. RAMSIER, Ag Spectrum.
Nonpoint source pollution by agricultural chemicals is of concern in the Midwest, especially given that the hypoxic zone in the Gulf of Mexico has been attributed to N use in the Midwest. We propose to reduce nitrate leaching through the use of surfactant and biostimulant in potato production. Research was conducted on a private farm in Arena, Wis. in the Lower Wisconsin River Valley. A surfactant and biostimulant were evaluated under two levels of N fertilization. Nitrate leaching was monitored weekly using soil water samples collected below the root zone with porous-cup soil water samplers placed at 1 m. Potato yields in 2000 were less than expected and considerably less than yields normal to this area. This lower response can be attributed to high rainfall amounts and intensities received during the growing season. This caused greater than normal nitrate leaching. In addition, late in the growing season, there were problems with weed (grasses) and blight infestations. However, reduced leaching of N and increased yield was observed with some of the treatments. In the 2001 season, we anticipate less leaching with biostimulant and surfactant compared to the control.
Phosphorus Leaching Under a Restored Tallgrass Prairie and Corn Agroecosystems. K.R. BRYE*, Univ. of Arkansas-Fayetteville, T.W. ANDRASKI, W.M. JARRELL, L.G. BUNDY, J.M. NORMAN, Univ. of Wisconsin-Madison.
Most studies of phosphorus (P) movement in soil have based their conclusions on patterns of extractable soil P as a function of depth, which has led to the assumption that no substantial leaching loss occurs because of high P-fixation capacity in mineral soils. Few studies have involved high-quality leachate samples collected below the root zone. Equilibrium-tension lysimeters installed at a depth of 1.4 m were used to evaluate and compare P leaching from a restored tallgrass prairie and nitrogen (N)-fertilized (f) and N-unfertilized (nf), no-tillage (NT) and chisel-plowed (CP) corn agroecosystems on a silt loam soil in south central Wisconsin during a 5-yr period. Mean volume-weighted molybdate-reactive P and total dissolved P concentrations were similar within replicate samples, but always higher in NTf corn than in the prairie or CPf corn systems, though drainage from the CPf corn was always higher than from the NTf corn system. Leachate-P concentrations from the natural and managed agroecosystems exceeded 0.01 mg P/L and leaching losses were significantly higher from N-fertilized corn, regardless of tillage, than from the prairie or N-unfertilized corn systems, from which leachate-P concentrations and loads were similar. Preliminary results indicate a potential Nfertilization effect on P leaching.
Development and Evaluation of a Coupled GIS-Pesticide Modeling System . J.P. DEGROOTE*, H.S. LIN, Univ. of Wisconsin-Stevens Point, B. LOWERY, K. MCSWEENEY, Univ. of Wisconsin-Madison.
A coupled system comprised of customized ArcView GIS extensions and a Windows version of the pesticide modeling program Pesticide Root Zone Model (PRZM-3) has been developed. The ArcView extensions utilize the Soil Survey Geographic Database (SSURGO) soils data to develop inputs for running the PRZM3 model. Further tools have been developed in ArcView for post-processing results for display in tables, charts and graphs in ArcView. The system can be used to easily carry out pesticide vulnerability assessments at a watershed or county level. The predictive capability of the system was evaluated by comparing to measured field data on a silt loam soil in Wisconsin. The system produced a reasonable approximation of the actual cumulative drainage at 1 m over a seventeen month period. The system also produced a close approximation of the movement of a bromide tracer. Original simulated movement of metolachlor and atrazine was underpredicted when compared with measured data. Using the Monte Carlo capabilities of PRZM-3 it was demonstrated that the model routine to calculate the pesticide partition coefficient based on the organic carbon content from the SSURGO database controlled a large amount of possible variation in the output. Lowering the organic carbon content inputs produced a more reasonable match between simulated and measured data.
Management Practice Effects on the Potential for P Loss from Midwestern Soils. R.G. HOEFT*, L.G. BUNDY, Univ. of Wisconsin-Madison, A. MALLARINO, Iowa State Univ., INES DAVEREDE, Univ. of Illinois.
Nutrients are estimated to be the third leading cause of contamination of fresh surface waters in the U.S. Contamination from nutrients ranks 1st in Illinois, 3rd in Iowa, and 5th in Wisconsin. Nitrogen contamination of surface waters increases the potential for health risk and increased eutrophication. In most waters, eutrophication is limited by inadequate levels of P. In an attempt to assess or limit the potential for contamination of water bodies, both Iowa and Wisconsin are or have recently established P index systems. The Illinois legislature enacted legislation that limits manure application to P removal when soil test levels exceed 150 ppm P. Research is in progress in all three states to ascertain the impact of soil test, soil type, method and rate of manure and fertilizer application, manure type, tillage, and plant residue on P runoff. Preliminary results show 1) a strong relationship between soil test P and soluble P concentration in runoff; 2) relatively high concentrations of soluble P associated with surface application of manure irrespective of soil test; 3) inconsistent changes in DRP loads in surface runoff from surface application of manure; 4) decreased concentration of total P on no-till as compared to tilled fields; and 5) excess P concentrations in animal diets increase the risk of total and soluble P losses in runoff.
Statistical Assessment of Soil Variability from Profile Cone Penetrometer Data. A.T. WOOD*, J. ZHU, B. LOWERY, Univ. of Wisconsin-Madison.
Data describing spatial variability of soil hydraulic properties necessary for assessing water and solute fluxes at a field scale are often lacking. There is a need for good quality three-dimensional (3-D) soil physical property data. We are using innovative geostatistics methods for assessing soil profile differences on a field scale. The overall objective is to develop 3-D soil-hydraulic landscape models based on innovative measurement techniques, digital elevation models (DEM) and geostatistics to quantify profiles of soil physical and hydraulic properties. Data were collected with a penetrometer to a depth of 1.4 m. These data were then averaged every 3 cm for clustering techniques. Three cluster groups were used to generate a map to differentiate between measured points. To identify boundaries between clusters, penetrometer readings at the plow layer were extracted and kriged. The cluster based map allows for distinguishing among soil physical properties including in situ measured saturated soil hydraulic conductivity.
Nitrate Leaching to Groundwater: Surfactant Use. T. NEHLS*, B. LOWERY, Univ. of Wisconsin-Madison.
Nitrate-N levels exceed the drinking water standard in 20 to 25% of the wells in the Central Sands Area of Wisconsin. Potato production on sandy soils under irrigation causes a dry zone 30 cm below the top of the potato hill. Water and fertilizer uptake by potatoes in this zone is reduced. Previous research shows use of a nonionic surfactant, which decreases the surface tension, increases soil water content in this zone and decreases nitrate-N leaching. Soil water suction-cup samplers installed at 1 m and groundwater monitoring wells placed below the water table were used to assess nitrate-N leaching. In general, water samples collected in the 2000 growing season exceeded the drinking water standard. Overall nitrate-N concentrations were slightly greater for the control compared to samples from surfactanttreated portion of three fields. The average concentrations of soil water samples for the season were 40.8 and 40.7 mg/L nitrate-N for the control and surfactant, respectively, and 24 and 32 mg/L nitrate-N for the control and surfactant, respectively for groundwater. The depth to the water table at the three sites ranged from 1.5 to 13 m. There were no significant differences between treatments, which may be due to frequent rain events shortly after N fertilizer application.
Division S-8 - Nutrient Management and Soil and Plant Analysis
Development of a Manure Testing Manual by a Multi-Regional Committee. J. PETERS*, Univ. of Wisconsin-Madison, D. BEEGLE, Penn State Univ., S. COMBS, Univ. of Wisconsin-Madison, B. HOSKINS, Univ. of Maine, J. KOVAR, Natl. Soil Tilth Lab., M. WATSON, Ohio State Univ., A. WOLF, Penn State Univ., N. WOLF, Univ. of Arkansas.
The benefits of applying livestock manure to crops have been recognized for centuries. Nutrient composition of manure varies with a number of factors, including: animal type, bedding, feed ration, storage/handling, environmental conditions, field application method, and age of manure. Quantifying the nutrient value of applied manure remains a complex challenge, however, this information is needed to better manage manure as a nutrient asset. Work on the development of this multi-regional publication began in 1996 following a joint meeting of regional soil testing workgroups in Raleigh, North Carolina. Earlier in that year, a sample exchange was conducted with NCR-13, SERA-6 and NEC-67 laboratories. Results from that sample exchange were presented at the Raleigh meetings and sparked interest in joining efforts to develop a manure testing manual, which could be used in all regions. Work on the manual has been focused on four main areas, including: sampling, analytical procedures, lab QA/QC, and reporting. The analytical section includes suggested methods for sample handling, dry matter determination, total N, ammonium N, digestion/ dissolution and analytical methods for minerals, pH and electrical conductivity.
Division S-11 - Soils and Environmental Quality
Water-Soluble Phosphorus Forms in Manure-Amended Soils. L.W. GOOD*, L.R. COOPERBAND, Univ. of Wisconsin-Madison.
Our research evaluates the effect of soil test phosphorus (STP) on P losses to water from manure-amended soil. We applied fresh dairy manure (DM) or poultry litter (PL) at a total P rate of 54 kg/Ha to Plano silt loam with different Bray- 1 P values resulting from different frequencies of prior dairy manure applications (none, two, or five applications over six years). The mixed soils, plus calcium phosphate- and non-amended controls, were placed in containers allowing drainage. They were incubated for 24 weeks with weekly saturation and drainage. PL-amended soils initially had higher drainage water dissolved reactive P (DRP) than DM-amended soils, but over the course of the incubation this was reversed. The pattern for water-extractable P was similar. Comparing the two previously manured soils amended with PL, drainage water DRP and water-extractable DRP were not significantly different regardless of STP. Surprisingly, when mixed with DM, the soil that was manured only two times previously had higher DRP concentrations than the more frequently manured one. It also had a significantly lower capacity to sorb additional P. Our results indicate that there are clear differences among animal manures that should be considered to minimize runoff P losses from manures applied to cropland.
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