Abstract Writing



An abstract is a mini version of a paper. It should be the shortest possible.


This is the shortest abstract ever written














How should an abstract be written?


Work with a partner and try to write true or false next to the following sentences,


An abstract


1)       should state the principle objectives and scope of the investigation

2)       should not describe the methods employed

3)       should summarize the results

4)       should not state the principal conclusion

5)       should be written in the Present Continuous tense because it refers mostly to work being done at present.

6)       Should not exceed 450 words.

7)       Should cite references to the literature used.














Analyze the following abstracts and try to find the lines correspondiing to the Introduction, Methods and materials, Results, and Discussion. (IMRAD)


The annual American Society of Agronomy/Crop Science Society of

America/Soil Science Society of America meetings were held Nov. 3-8 in

Indianapolis, Indiana. Over 20 department faculty, staff and students

participated in oral presentations and poster sessions. The following is a list of titles with links to the full abstract and author home page (where available).



Div. A-5 - Environmental Quality


Non-Equilibrium Field-Scale Pesticide Transport: Soil Cores vs. Solution

Samplers. T.J. GISH*, K.J.S. KUNG, C.S. HELLING, D. GIMENEZ, and A.

SHIRMOHAMMADI. USDA-ARS, Univ. of Wisconsin-Madison, Univ. of Maryland.


Soil cores and solution samples are routinely removed from fields

and used to characterize solute transport to ground water

underlying agricultural fields. Atrazine, deethyatrazine (DEET)

and bromide concentrations were monitored through the top 1.8 m

of soil in no-till and tilled fields. Eighteen soil cores were

removed throughout the year. These data were compared to results

from 144 suction lysimeters sampled after every >10 mm rain

event. At early times (<3 wks after application), atrazine and

DEET concentrations observed in the soil cores and from solution

samplers were not in equilibrium. The greater volume-normalized

herbicide concentrations observed in the solution samplers is

likely a result of preferential transport.


Div. A-6 - International Agronomy


An Assessment of Soil Quality in a Hillside Agroecosystem of Honduras. P.

ERICKSEN* and K. MCSWEENEY, Univ. of Wisconsin-Madison.


Our study was conducted in a catchment (950 ha2) occupied by two

communities in the Dep. of Francisco Morazon in central Honduras.

The soils are derived from volcanic materials and elevation

within the catchment ranges from 1100 to 1850 m. Subsistence

agriculture and cattle grazing are the primary activities,

although a considerable portion of landscape contains primary and

secondary forest of pine and some hardwood. Our objective was to

identify and interpret soil landscape processes operating at

different scales and under different land uses. We hypothesized

that at the catchment scale patterns of land use can be explained

by the productive potential and constraints of the land. The

mosaic of patches of intensive agricultural-, pasture-,

abandoned-land, and primary forest supports the notion that

farmers have by trial-and-error matched their land use to the

intrinsic variation in the landscape. At the fine or plot scale,

a variety of physical, chemical, and biological attributes were

measured at 20 sites representing different land uses, to

determine if processes active at the sites were contributing to a

sustainable or deteriorating state of soil quality. Finally, a

semi-quantitative index of soil redistribution within and among

patches/plots was used for interpreting the impact of particular

land uses on adjoining land and water quality within the



Div. A-8 - Integrated Agricultural Systems


Soil Quality: Building a Flexible Framework Based on Farmer Input. K.

MCSWEENEY*, R.F. HARRIS, P. ERICKSEN, and D. ROMIG, Univ. Of Wisconsin-Madison.


We will present a synthesis from several studies conducted with

farmers concerning their assessment of soil quality/health. The

studies were conducted in Wisconsin, Honduras, and Costa Rica. A

major impetus was to establish links between farmers and

scientists' perception and knowledge about soil quality as a

basis for developing participatory approaches for soil

management. Common findings among the studies include: (1)

farmers tend to use variety of non-soil attributes (e.g., plant

health, water quality) as well as descriptive and analytical

attributes for soil quality assessment; (2) spatial and temporal

perspectives of soil quality differ among scientists and farmers;

the "universe" and purpose that farmers employ for soil quality

assessment may be quite different from that of scientists. These

and other findings will be presented as considerations for

development of frameworks for soil quality assessment that use

farmer input.


Div. C-6 - Crop Quality and Utilization


Weather and Alfalfa Quality in Wisconsin. W.L. BLAND*, V.R. KANNEGANTI, and D.J. UNDERSANDER, Univ. of Wisconsin-Madison.


Nutritional quality of forage fed to dairy cows has enormous

financial implications for Wisconsin producers. The ability to

predict quality in the growing crop is needed for scheduling

harvest and to simulate and analyze forage systems. Prediction

methods that depend on observations of plant development show

promise for harvest management, but are not suited to,

simulation. Results of environment-driven attempts at modeling

changes in forage quality remain disappointing. A dataset is

available in Wisconsin of more than 1000 samplings of alfalfa

made by county Extension staff in a program to advise farmers on

optimal time of harvest. Data span a 5-yr period, 38 counties,

and are typically three to five samples from a site prior to

harvest. The ratio ADF/NDF is 0.83+0.02 for the majority of

samples, although for a few counties this ratio is 0.74+0.02

consistently. Change of NDF in time is linear, with slopes

varying from 0.2 to 1.1% d-1; this slope is unrelated to

latitude. A mechanistic simulation model appears to be required

for a robust prediction system.







Div. S-1 - Soil Physics


Impact of Funnel-Type Preferential Flow on Sampling. K.J.S. KUNG*, S.H. JU, and C. HELLING, Univ. of Wisconsin-Madison and USDA-ARS.


Soil-solution sampling methods developed over 50 yr ago are still

routinely used to monitor fate and breakthrough curve (BTC) of

contaminants in unsaturated soils. Conventionally, assumptions

have been that: (1) concentration-based BTC (ABTC) and mass-flux

based BTC (MBTC) are identical; and (2) BTC from samples (SBTC)

would become accurate when enough samples are collected.

Numerical simulations were conducted in twelve 2-D hypothetical

profiles with funnel flow paths to test the validity of these

assumptions. Simulated results indicate that: (1) MBTC ultimately

is the most representative leaching pattern to indicate the

loading of a contaminant at a certain soil depth; and (2) ABTC

always significantly underestimates MBTC. By increasing the total

number of randomly located samples, SBTC will never accurately

indicate MBTC. The SBTC could be modified to better estimate MBTC

when preferential weight is assigned according to the local water

flux. However, the SBTC from soil coring methods would always

underestimate MBTC.


Frequency-Domain Reflectometry for Water Content Measurement Using a

Network Analyzer at Radio Frequencies. G.C. STARR* and B. LOWERY, Univ. Of Wisconsin-Madison.


Instrumentation and methodology for an electrodynamic technique

called frequency-domain reflectometry (FDR) to measure soil water

content using a network analyzer have been evaluated. The

approach is similar to time domain reflectometry (TDR), and the

same probes are used for each technique. The FDR approach

measures dielectric constant to derive water content.

Measurements are made of reflected power vs. frequency, and data

are transformed by the network analyzer to reflected power vs.

effective probe length using an inverse Fourier transform. FDR

provided a reliable measure of [Image]v in Sparta sand (sandy,

mixed, mesic Entic Hapludolls). [Image]v was measured from 0.250

to 0.020 m3/m3, with an accuracy of 0.0015 m3/m3. A linear

calibration of [Image]v vs. Ka1/2; was found with an r2 of 0.999.


The advantages of FDR for sandy soils are improved signal:noise

ratio and better resolution, resulting in greater accuracy and

sensitivity. FDR contains a built-in computer that produces

simpler waveform analysis and greater versatility in data

handling over TDR. The cost of FDR is comparable to that of TDR.

The signal:noise ratio is about 250:1.


Measuring Instantaneous Solute Flux and Loading with Time Domain

Reflectometry. G.L. HART * and B. LOWERY, Univ. of Wisconsin-Madison.


Time domain reflectometry (TDR) has become a popular method of

measuring water content and conservative tracer concentration in

soils. We investigated the use of TDR for monitoring variable

flux contaminant loading in a rapidly draining sandy soil on a

real-time basis. This is feasible because of the ability to

acquire rapid, multiplexed measurements of both variables

necessary for calculating loading - water flux and resident

contaminant concentration. Waveguides for TDR monitoring

generally measure small spatial boundaries, allowing the

implementation of simplifying assumptions for estimating flux.

Results of laboratory experiments conducted under steady-state

and transient-flow conditions were compared. Combining data from

steady-state and transient-flow experiments, average mass balance

recovery ratios of 113% for water and 104% for a bromide tracer

were obtained. LEACHM simulations were in good agreement with TDR

monitored transient-flow data. Under steady-state conditions,

LEACHM was unable to accurately predict pore water velocity.

Adjusting the effective porosity lead to quantification of an

immobile water content of 0.03 m3 m-3. Use of TDR is envisioned

as an excellent means of advancing understanding of transport



Div. S-2 - Soil Chemistry


Binding of Mercury (II) in Soil Organic Matter. U. SKYLLBERG*1, P. R.

BLOOM1, E. A. NATER1, K. XIA2 and W. BLEAM2, 1Univ. of Minnesota and 2Univ.

of Wisconsin-Madison.


Natural organic matter (NOM) is a dominant factor behind the

retention and mobility of anthropogenic Hg (II) deposited in

forested ecosystems. Based on the very high affinity of Hg (II)

for R-SH groups, we hypothesize that reduced S sites bind Hg (II)

in NOM. To test this, competitive studies between Hg (II) and

metals with different affinity for R-SH were combined with XANES

(X-ray absorption near edge spectroscopy) and XAFS (X-ray

absorption fine structure) studies for a range of NOM samples

taken along two upland-wetland transects in northern Minnesota.

In Ca and Al nitrate dissolved Hg (II) was due solely to the

solubilization of NOM, whereas Cu (II) was found to compete with

Hg (II) for binding sites. XANES showed that a wide ratio of

reduced to oxidized S occurs in NOM. XAFS of Hg (II) substituted

NOM showed that reduced S participates in the Hg (II) bonding in

samples with a high ratio of reduced to oxidized S. The strong

binding of Hg (II) to reduced S in NOM imply that at present

concentrations of Hg (II) in northern forest ecosystems (100 -

500 ng Hg (II) g-1 [NOM]), the mobility of Hg (II) and its

transport from soils to surface waters is highly dependent on the

solubility of NOM and less dependent on variations in the

speciation of mercury (II).


Complexation Constants of Cadmium, Copper, and Zinc with Soil Organic

Matter. K. XIA*, P.A. HELMKE, and W.F. BLEAM, Univ. of Wisconsin-Madison.


Trace metals bound to soil humic substances are commonly assumed

to be exchangeable. The exchange behavior of Cu. Cd, and Zn bound

to soil humic substances was determined in isolation from the

effects of soil reactions. The soil humic substances were

extracted with Chelex-20 ion exchange resin from a Plano silt

loam (Typic Argiudolls) treated with and without sewage sludge.

The extracted humic substances were titrated with Cu2+, Cd2+,

Zn2+, and Ca2+ and the equilibrium activities of the trace metals

determined by our procedures of Donnan membrane analysis and

graphite furnace atomic absorption spectrophotometry. The

exchangeability of metals on the extracted soil humic substances

increased with metal loading rates.


Ion Transport Measurements in Soils by Use of Custom-Built Ion-Selective

Microelectrodes and Computer-Driven Micromanipulator and Data-Logger. L.A.

SHERMAN* and P. BARAK, Univ. of Wisconsin-Madison.


Transport of major ions in soils due to processes such as mineral

dissolution result in microscopic ion concentration gradients in

soils. Ion gradients are usually measured using destructive

one-time sampling techniques and measurements limited to planar

geometries. Novel ion-selective microelectrodes were constructed

to allow measurement of the development of ion gradients in soils

over time and gradients of any spatial geometry. Use of a

computer-driven xyz micromanipulator and data-logger yields

precision placement of electrodes and automated data recording.

The transport of major ions due to the dissolution of agliming

and fertilizer materials in soils was measured with the

microelectrode/micromanipulator system. The soil amendments were

placed in contact with a silt loam soil in a custom-built

diffusion cell under a controlled temperature and moisture

regime. The development of microscopic ion gradients of various

geometries was measured with a spatial resolution of 2 mm and on

time scales ranging from hours to days.


Role of Metals and Complexing Agents on Mineralization of Soil Organic

Phosphorus by Root-Released Enzymes. X. HE and P. A. HELMKE*, Univ. of



Up to one-half of the total P in some soils is associated with

soil humic substances. The bioavailability of the P associated

with soil humic substances depends on processes that mineralize

the organically bound P. The interactions of Fe, Al, and trace

metals and metal complexing agents exuded by plant roots on the

effectiveness of acid phosphatases and phytase to mineralize P

bound to soil humic substances were determined. Some metals

strongly inhibit P mineralization reactions, but the effect is

ameliorated by low concentrations of citric acid. It appears that

phytic acid and other P humic substances form insoluble trace

metal complexes that are nonreactive with phosphatases but that

their reactivity is restored by removing the metals with metal

complexing agents.


Effects of Organic Residues and Calcium and Magnesium from Dolomite on Soil

Acidity and Activity of Trace Metals. J.A.G. SANTOS*, S. BUZETTI, and P.A.

HELMKE, Univ. of Wisconsin-Madison.


The effects of lime and solid (SOR) and liquid organic residues

(LOR) from petroleum wastes on soil acidity and exchangeable Ca

and Mg were studied under laboratory conditions. Three kilograms

of a disturbed Oxisol were treated with (3X) four rates of SOR

and two rates of dolomite or three rates of LOR and two rates of

dolomite to increase the base saturation to 50 and 100%, plus

controls. The addition of 18 g of SOR or 0.285 L of LOR reduced

reactive acidity and exchangeable Al as efficiently as adding

dolomite to 100% of the base saturation. The total saturation

water-extractable concentrations of Cu, Zn, and Cd were

determined by ICP-OES and the concentrations of their free ions

were determined by Donnan membrane equilibrium to study effects

of the treatments on the solubility of trace elements.


Indigenous Free Ion Activity of Zinc as a Function of pH in Water

Saturation Extracts of Soils from Brazil, North America, and Australia.




The free ion activity of Zn was determined in water saturation

extracts of soils from Brazil, North America, and Australia as a

function of pH by our methods of Donnan membrane equilibrium

analysis. The indigenous pH of the soils ranged from 5 to 8.5.

Typical values of the activity of Zn2+ in the extracts ranged

from 1 to 10 µM. Slopes of the relationship pZn2+ versus pH

(pZn2+ = a + b·pH) ranged from 0.25 to 0.7. These values are

similar to those found by many other researchers for total pZn as

a function of pH. A slope of 2.0 is predicted by the hypotheses

that the solubility of franklinite (ZnO·Fe2O3) controls the

solubility of Zn2+ in soils. The results obtained in this

research do not support the franklinite hypothesis.


Div. S-3 - Soil Biology and Biochemistry


Diagram-Assisted Redox Model for Mass Balancing Bioremediation by

Microorganisms. R F. HARRIS* and W. J. HICKEY, Univ. of Wisconsin-Madison.


The model is based on sequential derivation of mass balance

coefficients for microbial growth (biosynthesis and maintenance)

and co-metabolism as a function of assimilatory electron donor,

C, N, P, and S nutrients, dissimilatory electron donor and

electron acceptor couples, and experimental and theoretical

growth yields and metabolic pathways. Use of the model is

initiated by entry into a blank electron flow diagram of the

empirical molar composition and redox properties of the

substrates, biomass and metabolic byproducts of the hypothesized

microbial reaction. Derivation of stoichiometric coefficients for

the reaction is assisted by reference to the diagram as well as

by use of integrated mass balance equations. Provisions for

endogenous metabolism, death and cryptic growth are also

included. The model is illustrated by application to aerobic

trichloroethylene degradation stimulated by methane and ammonium.


Div. S-4 - Soil Fertility and Plant Nutrition


Effect of Calcium and Magnesium Concentrations on the Uptake of Copper,

Iron, Manganese and Zinc by Lettuce, Lupin, Soybean, and Wheat. S.

BUZETTI*, J.A.G. SANTOS, and P.A. HELMKE, Univ. of Wisconsin-Madison.


The effects of Ca and Mg on the uptake of Cu, Fe, Mn, and Zn by

lettuce (Latuca sativa L.), lupin (Lupinus albus L), soybean

(Glycine max L. Merrill), and wheat (Triticum aestivum L.) in

hydroponic culture was determined in half-strength Hoagland

solution for 28 days with three rates of Ca (0.5, 2.0, and 8.0

mM) and three rates of Mg (0.25, 1.0, and 4.0 mM). The experiment

was set up as a completely randomized design in a factorial

scheme. Calcium rates influenced soybean growth and the Cu, Fe,

Mn, and Zn content of the shoot and root of lettuce and soybean.

Variation of the Ca in the solution from 0.5 to 8.0 mM reduced

the accumulation of Cu, Fe, Mn, and Zn in soybean and in the

accumulation of Mn and Zn in lettuce. Increasing the rate of Mg

reduced Cu and Mn in soybean roots and Zn in the lupin and wheat



Influence of Nitrogen Timing and Irrigation Methods for Potatoes. S.A.

WILNER*, K.A. KELLING, and L.R. MASSIE, Univ. of Wisconsin-Madison.


Split applications of N fertilizers banded on the row or applied

through irrigation systems to potatoes may result in greater

uptake efficiencies and lower leaching potentials, especially

under precession irrigation methods. This study was designed to

determine the effects of four NH4NO3 fertilizer management

regimes under trickle or sprinkler irrigation systems on a

Plainfield loamy sand (mixed, mesic Typic Udipsamments) at

Hancock, Wis. Overall yields for 1995 were about 30% lower than

normal and may have been limited by an infestation of

Verticillium dahliae, yet some trends appeared evident. In

general, sprinkler irrigation produced significantly higher tuber

yields than did the trickle system when averaged across

fertilizer treatments. Surface banding the N on top of the row,

split between emergence, tuberization, and tuberization +15 days

resulted in higher tuber yields and quality than when the N was

applied by fertigation. Additional splitting of the N did not

show any extra benefit. Based on petiole NO3-N values, it appears

that banded N with the trickle system may have been positionally

unavailable early in the growing season but maintained plant N

levels longer.


Crop Residue Effects on Nitrogen Availability in No-till Corn. L.G BUNDY*

and T.W. ANDRASKI, Univ. of Wisconsin-Madison.


In northern climates, reduced N availability in no-till

continuous corn (Zea Mays L.) frequently occurs. A 3-yr field

study was conducted to identify potential mechanisms contributing

to reduced N availability in no-till corn and to evaluate

management approaches for avoiding N deficiencies. The effects of

residue level (0x, 1x, 2x), N rate (0 to 224 kg N ha-1), and N

source and placement variables on N availability and yield were

investigated. Net N mineralization during the early corn growing

season decreased as residue levels were increased from 0x to 2x.

Artificial (polypropylene) residue and 1x corn residue providing

similar soil cover showed similar net N mineralization. Soil

temperatures at a 10-cm depth with 0x residue were 4&deg;C higher

than with 2x residue, and 2&deg;C higher than both 1x and

artificial residue treatments. Corn yields decreased with

increasing residue level at 0 and 90 kg ha-1 N rates. Yield

response to N sources and placement methods suggests that NH3

losses from surface-applied urea-containing fertilizers were low.

Results indicate that reduced N availability in no-till corn is

primarily due to slower N mineralization caused by lower soil

temperatures in high residue systems rather than to

immobilization of N in residues.


Div. S-5 - Pedology


The NSSC Database for Permafrost-Affected Soils (Gelisols). J.G. BOCKHEIM,

J.M. KIMBLE*, C.L. PING, and J.P. MOORE, Univ. of Wisconsin-Madison, NRCS,

and Univ. of Alaska.


The National Soil Survey Center database contains 96 pedons with

a pergelic soil temperature regime, half of which are classified

as Pergelic, Histic Pergelic, or Pergelic Ruptic-Histic

Cryaquepts. Eighty of the pedons satisfy the requirements of the

new Gelisol order (gelic material and permafrost within 100 to

200 cm of the surface) and represent 12 of the 20 great groups.

Only seven of the Gelisol pedons have an active layer (depth of

seasonal thawing) deeper than 100 cm (the average depth = 49 cm).

More than two-thirds of the pedons feature cryoturbation (frost

churning), which is used to distinguish mineral soils at the

suborder level. Although more than half (58%) of the pedons have

an aquic soil moisture regime, the thickness of the organic layer

is used as the first cut to distinguish Gelisols at the

great-group level. The organic layer thickness is highly

correlated (p = 0.006) with active layer thickness.


Soil Studies in the Lower Kolyma River Area, Far Eastern Russia. J. M.


1USDANRCS-NSSC, 2Agri. and Agri-Food Canada, Ottawa, 3Univ. of

Wisconsin-Madison,4Univ. of Alaska, Fairbanks.


A joint mapping and soil characterization project was carried out

in the far North Eastern part of Russia in 1994 near Cherskiy.

The area is largely unglaciated with a strongly continental

climate. The MAAT is about -13&deg;C, with an annual

precipitation of 220 to 240 mm. Field samplings and mapping were

carried out in three different areas: Rodinka Mountain,

characterized by frost-shattered bedrock and residuum under

alpine vegetation; Duvanny Yar, which is an exposure of silt and

syngenetic ice complexes along the Kolyma River; and the Kurishka

Tundra, which was on the coastal tundra zone of the East Siberian

Sea. Characterization data along with the soil maps are

presented. There was a major lack of cryoturbation as compared to

similar areas in Canada. Relationships between Soil Taxonomy, the

Canadian and Russian taxonomic systems are discussed.


Development of a Three-Dimensional Soil-Landscape Model for the Loess

Mantled Region of Southwestern Wisconsin. P.K. FALK*, K. MCSWEENEY, and

S.J. VENTURA, Univ. of Wisconsin-Madison.


The loess-mantled ridge and valley topography of the Driftless

Area in southwestern Wisconsin constitutes a fragile environment

that is strongly controlled by the underlying bedrock. We will

present a three-dimensional soil-landscape model, which

incorporates geostatistical analysis of data at both fine and

coarse scales. Attributes used in the model fall into five

categories: attributes related to topography, soil physical

properties, soil chemical properties, microclimate, and

vegetation. Initial results indicate amounts of phosphorus and

potassium are lower on south-facing than north-facing slopes. In

addition, cultivation provides marked local variation in amounts

of these attributes at finer scales. The addition of past land

use history, soil biota and vegetation to the model provides

additional characterization of this human modified ecosystem, and

potentially, additional explanation of soil forming processes.


Micromorphological Alterations of Soils Under Long-Term Contrasting Prairie

Management Systems. K.L. MALTONI*, UNESP/Ilha Solteira, Brazil, K.

MCSWEENEY, Univ. of Wisconsin-Madison, and G. LEMASTERS, Dep. of Agric.

Resource Management.


Five contrasting prairie management treatments were established

at three sites at the University of Wisconsin Arboretum in 1940,

1950, and 1956. The treatments consist of 'restored', 'burned',

'harvested', 'mulched', and 'bare'. We investigated the impact of

biomass management on surface soil structure. The 'restored'

treatment has developed a strongly aggregated structure. The

structure of the 'burned' treatment closely resembles that of the

'restored' treatment, but shows some evidence of platyness. The

remaining treatments all exhibit platy structure and associated

vesicular porosity, which is most strongly expressed in the bare

treatment. The bare treatment has a strongly developed surface

seal. We attribute the platy structure to repeated cycles of

freeze/thaw and wet/dry. Evidence of incorporated biomass and

earthworm activity in the soils decreased as follows: harvested,

mulched, bare, which is matched by an increase in area of platy

structure. Reduced biological activity appears to be associated

with the persistence of platy structure in these treatments.


Div. S-6 - Soil and Water Management and Conservation


Carbon and Nitrogen Cycling on an Ecosystem Gradient from Cultivated Corn

to Natural Prairie. KR. BRYE*, J.M. NORMAN, L.G. BUNDY, and S.T. GOWER,

Univ. of Wisconsin-Madison.


A study was undertaken to evaluate, characterize, and model

various components of the C and N cycles of several common and

historic land use patterns of Wisconsin (e.g., chisel plow and

no-till corn, and natural prairie). The ecosystems under

investigation reside on a silt loam soil with similar edaphic

properties and morphological characteristics. In April 1995,

initial total soil C and organic matter content for the top 3-cm

layer were the same in all ecosystems. Nitrate leaching and

drainage were quantified in the field usimg suction plate

Iysimeters. The chisel plowed corn ecosystem had greater

cumulative drainage from July 1995 through May 1996 than the

other two ecosystems, where the prairie's drainage was 10 times

less than that measured under cultivation. Cumulative,

post-growing season NO3- leaching losses between October 1995 and

April 1996 were 12.4, 7.4, and <0.05 kg NO3-N ha-1 for the chisel

plow, no-till, and prairie systems, respectively. The differences

in NO3- leaching can be attributed to decreasing drainage and

substantially lower soil solution NO3- concentrations for the

prairie ecosystem. These results confirm the environmental

concern over groundwater contamination by nitrates associated

with production agriculture.


Div. S-8 - Nutrient Management and Soil and Plant Analysis


Selenium and Trace Metals in Forage Samples. L.S. ZHANG* and S.M. COMBS,

Univ. of Wisconsin-Madison/Extension.


The quality of forage samples was surveyed in terms of selenium

concentration, other major, minor and trace metal concentrations,

and concentrations of other components such as crude protein,

acid detergent fiber and neutral detergent fiber. The

concentrations of selenium and other major, minor, and trace

components were measured with hydride generation inductively

coupled plasma mass spectrometry after the samples were digested

with nitric acid and hydrogen peroxide. The selenium

concentration in these samples ranged between 0.82 and 0.03 mg

kg-1 with an average of 0.13+0.12 mg kg-1. The relationship

between selenium concentration and concentrations of other

components were sought.


Determination of Dissolved Organic Carbon by Inductively Coupled Plasma

Mass Spectrometry. S.M. COMBS, L.S. ZHANG*, and Y.J. LIU, Univ of



Inductively coupled plasma mass spectrometry was applied in the

determination of dissolved organic carbon (DOC) in aqueous

samples. Samples were passed through 0.45 µ m nitrocellulose

filter. Inorganic carbon was removed by purging samples with N2

gas after samples were acidified to ~pH 1 with nitric acid.

Volatile DOC was also removed. A carbon standard was made from

sucrose. As listed below, 12C and 13C can be used to measure DOC

in low and high concentration ranges respectively. The background

equivalent concentration (BEC) of 12C was 10 times higher than

its limit of detection (LOD). This high BEC might result from

atmospheric carbon and/or residual carbon in argon gas. Relative

to the determination of DOC by dichromate method, the ICP-MS

method is more rapid, easier, has an improved detection limit, a

broader dynamic range, and a more complete recovery of DOC.


12C 13C 12C 13C


Dynamic range mg 1-1 5-2000 20-16,000 BEC mg 1-1 17 20


Precision (%) < 3 < 3 LOD mg 1-1 1.5 5


Designing Soil Test Recommendations to Meet Multiple Goals—Production,

Economic, Environmental. K.A. KELLING* and S.M. COMBS, Univ. of



Soil tests are an index of nutrient availability for the field

sampled. Historically, soil test results have guided fertilizer

applications to help meet the production goals of the farmer. As

the research base supporting these soil tests increased, the

sophistication of Interpretation, including rate considerations

and economic evaluation, were increasingly incorporated into

recommendations. Additional factors such as soil yield potential,

crop to be grown, previous crop, tillage system, method of

fertilizer application, years for recommendation and expected

crop value have also been included at various times and places.

Although computers have allowed test interpretation to accept

this complexity, site-specific calibration and obtaining

sufficient input information have resulted in compromises for

most systems. Attempts are being made today to use soil tests for

other purposes, including environmental nutrient management and

regulation. Heretofore, research has guided test acceptability

and applicability for production and economic goals. As

demonstrated by recent research with soil P tests, routine field

testing may need to be modified for environmental



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