Content uploaded by Jeffrey D Wolt
Author content
All content in this area was uploaded by Jeffrey D Wolt on May 25, 2016
Content may be subject to copyright.
A meta-evaluation of nitrapyrin agronomic and environmental
effectiveness with emphasis on corn production in the Midwestern USA
Jeffrey D. Wolt
Research and Development Laboratories, Dow AgroSciences LLC, Indianapolis, IN 46262, USA; present
address: 164 Seed Science Center, Iowa State University, Ames, IA 50011-3228, USA; (fax: +1-515-294-2014;
e-mail: jdwolt@iastate.edu)
Received 3 April 2003; accepted in revised form 19 December 2003
Key words: Inorganic nitrogen, Leaching, Nitrification inhibitor, Nitrous oxide
Abstract
The effectiveness of nitrification inhibitors for abatement of N loss from the agroecosystem is difficult to mea-
sure at typical agronomic scales, since performance varies at the research-field scale due to complex interactions
among crop management, soil properties, length of the trial, and environmental factors. The environmental im-
pact of the nitrification inhibitor nitrapyrin on N losses from agronomic ecosystems was considered with empha-
sis on the Midwestern USA. A meta-evaluation approach considered the integrated responses to nitrification
inhibition found across research trials conducted in diverse environments over many years as measured in side-
by-side comparisons of fertilizer N or manure applied with and without nitrapyrin. The resulting distributions of
response indices were evaluated with respect to the magnitude and variance of the agronomic and environmental
effects that may be achieved when nitrification inhibitors are used regionally over time. The indices considered
共1兲crop yield, 共2兲annual or season-long maintenance of inorganic N within the crop root zone, 共3兲NO
3
-N leached
past the crop root zone, and 共4兲greenhouse gas emission from soil. Results showed that on average, the crop
yield increased 共relative to N fertilization without nitrapyrin兲7% and soil N retention increased by 28%, while N
leaching decreased by 16% and greenhouse gas emissions decreased by 51%. In more than 75% of individual
comparisons, use of a nitrification inhibitor increased soil N retention and crop yield, and decreased N leaching
and volatilization. The potential of nitrification inhibitors for reducing N loss needs to be considered at the scale
of a sensitive region, such as a watershed, over a prolonged period of use as well as within the context of overall
goals for abatement of N losses from the agroecosystem to the environment.
Introduction
The use of nitrification inhibitors is an established
agronomic practice for conservation of fertilizer ni-
trogen in the root zone where it may be utilized by a
crop. A side effect of this practice is environmental
protection afforded by the reduction of N loss from
the agroecosystem. A substantial amount of literature
details the environmental and agronomic performance
of nitrification inhibitors when used in combination
with N fertilizer or manure 共see Meisinger et al. 1980;
Wolt 2000兲. Even though most published data focuses
on nitrification inhibition as a crop production tool
共see, for instance, Meisinger et al. 1980兲, this same
body of information provides considerable insight as
to N stabilization through application of nitrification
inhibitors, with the consequences of altered move-
ment of N from the root zone by either leaching or
volatilization.
Nutrient Cycling in Agroecosystems 69: 23–41, 2004.
© 2004 Kluwer Academic Publishers. Printed in the Netherlands.
23
Nitrification inhibitor performance and variability
in response
As with any technology aimed at nutrient manage-
ment, nitrification inhibitor performance in reducing
N losses through leaching or volatilization will be
variable at the field level due to complex interactions
among crop management, soil, and environmental
factors. The microbial ecology of bacterial nitrifiers
is considerably influenced by multiple factors that
confound interpretations of nitrification inhibitor per-
formance 共Keeney 1980兲. The persistence and activ-
ity of nitrification inhibitors in the soil will also be
affected by many of these same factors 共Touchton et
al. 1978b; Wolt 2000兲. Thus, the year-to-year
performance of a nitrification inhibitor in a given field
or research plot may vary, even though the perform-
ance attributes of the nitrification inhibitor may be
evident when considered across a larger region, such
as a watershed or ecoregion, over time.
Nitrification inhibitors have been shown under a
variety of field and laboratory conditions to reduce
nitrate-N leaching as compared to fertilizer-only
treatments 共Wolt 2000兲. Reduced leaching is achieved
when nitrification inhibition in the crop root zone al-
lows for N to be retained in the upper soil profile and
utilized by the crop. This effect is best documented in
long-term lysimeter studies where annual reduction in
N loss is observed. For instance, Owens 共1987兲
showed that with 6 years continuous use of the nitri-
fication inhibitor nitrapyrin for corn production in
Ohio, USA, cumulative N leaching was reduced an
average of 20% in comparison to fertilizer application
without a nitrification inhibitor. Similar effects have
been shown in other environments 共Yadav 1997;
Randall 2000兲, but in contrast there are instances
where a variable benefit of nitrification inhibition is
observed 共see, for example, Timmons 1984兲.
The greenhouse gas nitrous oxide is produced in
soils during both nitrification of ammonium-N and
denitrification of nitrate-N, with the greater level be-
ing produced by denitrification. Accelerated nitrous
oxide fluxes from annual cropping systems are likely
a consequence of high N availability 共Robertson et al.
2000兲. There appears to be a direct effect of nitrifica-
tion inhibitors on reducing nitrous oxide produced
during nitrification, while the effect on denitrification
appears to be indirect from lower soil nitrate levels.
Bronson and Mosier 共1993兲reported that nitrification
inhibitors applied with N fertilizer decreased nitrous
oxide emissions by 43 to 71% when periodic
measurements were taken from time of fertilization to
harvest in a field trial of irrigated corn. In addition to
the effect on nitrous oxide loss from soil, there is
some evidence to indicate that nitrification inhibitors
also reduce the efflux of methane from soil, perhaps
through an indirect effect on methanotroph ecology
共Arif et al. 1996兲. The environmental benefit of
reduced greenhouse gas emissions may be offset by
efflux of acid-forming NH
3
in situations where nitri-
fication inhibitor use occurs in conjunction with sur-
face-applied urea or ammonium fertilizers in warm,
moist soils 共Harrison and Webb 2001兲.
Nitrification inhibitor performance in soils is most
effective and consistent when conditions favor slower
biological degradation of the inhibitor and reduced
Nitroso-group bacterial activity. Thus, optimal per-
formance is more common with late fall or early
spring application when soil temperatures are low.
These periods are associated with increased ground-
water recharge and runoff in continental temperate
climates due to lower evapotranspiration and seasonal
precipitation patterns. As a consequence of the tem-
perature effect, historical nitrification inhibitor per-
formance has generally been best in the upper
Midwestern USA as compared to more southerly cli-
mates. Nitrification inhibitor performance is best es-
tablished for corn, since this crop has an especially
high N requirement and is frequently grown on soils
with high N-loss potential, namely, poorly drained
soils, tile-drained soils, and irrigated sandy soils. The
efficacy and environmental effects of nitrification in-
hibition are best documented for the intense corn
production region of the upper Midwest. The greatest
environmental benefits of nitrification inhibitors nor-
mally occur when used with rates of N fertilization
that are well matched to crop N demand 共Wolt 2000兲;
therefore, nitrification inhibitor use is compatible with
other nutrient management technologies that improve
N-use efficiency.
Meta-effects evaluation of nitrification inhibitor
performance
The published literature regarding nitrification inhibi-
tor performance in the field focuses nearly exclu-
sively on the effects achieved at the research scale;
that is, individually, the data reflect performance at
the field or research-plot scale and over typical time
spans of one to three years. In contrast, any environ-
mental effect of nitrification inhibition on N loss will
be of consequence at the scale of a vulnerable water-
24
shed or larger over a period of many years. Crop ⫻
environment ⫻management factors contribute to
variability at the field scale that lends uncertainty to
the annual realization of microeconomic benefits
from nitrification inhibitors when used for yield en-
hancement 共Nelson and Huber 1980兲, even though
there may be societal benefits of nitrification inhibi-
tor use over broader scales of space and time for re-
duction of N loss from agroecosystems to the
environment. The research reported herein considers
comprehensively the environmental effect of nitrifi-
cation inhibition using a meta-evaluation approach
that probabilistically treats the distribution in out-
comes found across studies conducted in diverse en-
vironments over many years. The meta-evalution
approach entails integrated description of heteroge-
neous data. In the present case, data from short-dura-
tion agronomic trails conducted under diverse condi-
tions were integrated to allow for a generalized
assessment of agronomic and environmental effec-
tiveness. Such an approach provides insight in to the
environmental benefit that may be achieved when ni-
trification inhibition is used regionally over time.
Data detailing the effectiveness of the product
nitrapyrin 关2-chloro-6-共trichloro-methyl兲pyridine兴are
considered here, since this product has been used for
nitrification inhibition in the intense corn production
regions of the Midwestern USA for over 25 years and
its efficacy in controlling N loss is well documented
in the published literature.
Methods
A detailed review of published literature was con-
ducted to identify research trials where indices of ef-
fectiveness of nitrification inhibition were measured
in side-by-side comparisons of N fertilizer or manure
with and without added nitrapyrin. The indices
selected for consideration were 共1兲grain yield
共indicative of N availability and retention in the crop
root zone兲,共2兲annual or season-long maintenance of
inorganic N 共typically, NH
4
-N plus NO
3
-N兲within
the crop root zone, 共3兲N leached past the crop root
zone, and 共4兲gaseous flux 共typically N
2
O volatiliza-
tion兲from soil.
For those trials where relevant data were identified,
the relative effect of nitrapyrin was calculated as the
difference in effect observed for the comparable
treatment without nitrapyrin, expressed as a percent-
age of the effect without nitrapyrin 关共effect with ni-
trapyrin – effect without nitrapyrin兲⫻100/effect
without nitrapyrin兴, for a given location and year.
When the study design involved multiple compari-
sons, such as the effect of nitrapyrin over a range of
N levels or N sources, the average effect across these
treatments was determined. The intention of this
analysis is to consider the effects of nitrification inhi-
bition that may be expected with typical grower prac-
tice; therefore, control treatments receiving no N or
treatments using N fertilization rates well in excess
of crop N demand were typically not considered.
Treatments using nitrapyrin well in excess of the
maximum recommended use rate 共1.12 kg ai ha
–1
;
Dow AgroSciences 1999兲were also excluded from
consideration.
For many of the studies reported, the original re-
sults were summarized in figures. In these instances,
the relevant information for comparisons of nitrapy-
rin effect were translated from graphical to tabular
form by scanning the figures and extracting the data
using UnGraph version 4.0 共BIOSOFT, Cambridge,
UK兲.
The data from the literature were used to develop a
statistical distribution of relative effect of nitrapyrin
on the indices of interest, from which the grand mean
and standard error in response across studies were
developed and probabilities of nitrification inhibitor
effectiveness were determined.
Results
Grain yield
The database developed describing the effect of
nitrapyrin on grain yield consists of 189 observations
comprising 437 mean comparisons across 158 loca-
tion–years of experiments 共Table 1兲. The preponder-
ance of data are for field corn yield, but yields of
wheat, grain sorghum, and sweet corn are also
included. These data reflect studies conducted princi-
pally in the Midwestern USA, but also include results
from transitional climate zones in the Southeastern
USA and from Europe. The distribution in mean re-
sponse for a given yield comparison ranges from
⫺20.1 to 60.9%, with 141 of 189 observations
showing a positive effect of nitrapyrin on yield 共Fig-
ure 1兲. The grand mean 共⫾standard error of the
mean兲effect represents a relative yield increase from
nitrapyrin of 7.0% 共⫾0.8%兲. Although the data de-
scribing the effect of nitrapyrin on yield do not de-
25
Table 1. Relative crop yield from nitrapyrin when applied with sources of fertilizer or manurial N.
Nitrogen fertilization practice
Relative
effect
共%兲
a
Identity Crop Time Method Rate
共kg ha
–1
兲
Form
b
Soil 共subgroup兲Reference
3.0 Ames IA 1982 Corn Spring Inject 112, 224 AA Nicollet 共Aquic Hapludolls兲and Webster 共Typic
Hapludolls兲
Blackmer and Sanchez
1988
0.0 Ames IA 1983
5.1 Ames IA 1984
1.9 Nashua IA 1982 Readlyn 共fAquic Hapludolls兲
⫺20.1 Nashua IA 1983
0.3 Nashua IA 1984
1.9 Ames #1 IA 1985 Corn Spring Incorp 56, 112, 168 AS Nicollett 共Aquic Hapludolls兲Cerrato and Blackmer
1990
1.7 Ames #1 IA 1986
⫺5.1 Ames #1 IA 1987
5.2 Ames #2 IA 1985 Canisteo 共Typic Haplaquolls兲
5.5 Ames #2 IA 1986
4.9 Ames #2 IA 1987
⫺7.9 Holestein IA 1986 Galva 共Typic Hapludolls兲
⫺0.5 Holestein IA 1987
⫺2.0 Ida Grove IA 1986 Marshall 共Typic Hapludols兲
⫺7.7 Ida Grove IA 1987
0.3 Iowa City IA 1985 Mahaska 共Aquic Agriudolls兲
5.0 Kalona IA 1985 Bremer 共Typic Agriaquolls兲
⫺1.4 Kalona IA 1986
8.2 Kalona IA 1987
0.7 Marengo IA 1985 Nevin 共Aquic Agriudolls兲
⫺3.9 Marengo IA 1986
⫺4.8 Marengo IA 1997
⫺1.2 Williamsburg IA 1985 Mahaska 共Aquic Agriudolls兲
11.3 Bath Co. KY 1976 Corn Spring Surface 85, 170 AN Lowell silt loam 共Typic Hapludafls兲Frye et al. 1981
19.6 Lee Co. KY 1978 85, 170 Monongahela silt loam 共Typic Paleudalfs兲
11.8 Lewis Co. KY 1977 85 Cavode silt loam 共Aeric Ochraquults兲
17.4 Princeton KY 1974 140 Tilsit silt loam – Johnsburg silt loam intergrade
共Typic Fragiudults兲
21.8 Princeton KY 1975 140
42.4 Princeton KY 1976 110
7.9 Princeton KY 1977 90, 135, 180
⫺4.6 Princeton KY 1978 90, 135, 180
22.8 Buffalo ND 1997 Wheat Fall Inject 84 AA Gardena loam 共Pachic Hapludolls兲Goos and Johnson 1999
5.3 Knox Co. IN 1974 Wheat Fall Surface 44, 88 Urea Patton silty clay loam 共Typic Haplaquolls兲Huber et al. 1980
4.7 Knox Co. IN 1975 Fall Surface Urea Alford silty loam 共Typic Haplualfs兲
0.0 Knox Co. IN 1977 Fall Inject AA
26
Table 1. 共Continued兲.
Nitrogen fertilization practice
Relative
effect
共%兲
a
Identity Crop Time Method Rate
共kg ha
–1
兲
Form
b
Soil 共subgroup兲Reference
8.2 LaGrange Co. IN
1973
Fall Inject, sur-
face
AA, Urea
17.6 LaGrange Co. IN
1973
Fall,
spring
Surface Urea Elston sandy loam 共Typic Agriudolls兲
16.1 LaGrange Co. IN
1977
Fall Inject, sur-
face
AA, Urea Ockley silty loam 共Typic Haplualfs兲
17.5 Sullivan Co. IN 1973 Fall Surface Urea, AS, CN Elston sandy loam 共Typic Agriudolls兲
1.5 Sullivan Co. IN 1973 Fall,
spring
Surface Urea, AS, CN
20.0 Sullivan Co. IN 1974 Fall Surface AS, CN Patton silty clay loam 共Typic Haplaquolls兲
21.5 Sullivan Co. IN 1975 Fall Surface AS, CN
8.4 Sullivan Co. #2 IN
1975
Fall Surface AS, CN Elston sandy loam 共Typic Agriudolls兲
44.4 Sullivan Co. IN 1976 Fall Surface AS Patton silty clay loam 共Typic Haplaquolls兲
11.2 Sullivan Co. IN 1976 Fall,
spring
Surface AS
7.2 Buttlerville IN 1992 Corn Spring Inject 67, 174, 280 AA Silty clay loam Huber et al. 1993
6.6 Buttlerville IN 1992 67, 174, 280 SM
2.8 Lafayette IN 1992 84, 168 AA Silt loam
6.0 Lafayette IN 1992 84, 168 SM
1.8 Pinney #3 IN 1992 112, 224 AA Tracy sandy loam 共Ultic Hapludalfs兲
4.1 Pinney #3 IN 1992 112, 224 SM
7.3 Vincennes IN 1992 67, 123 SM Fine sandy loam
3.0 Brookston OH Corn Fall Inject 90, 112 AA, UAN Brookston silty clay loam 共Typic Agriaquolls兲Johnson 1995
7.5 Brookston OH Spring 90, 112
10.7 Crosby OH Fall 112, 180 Crosby silt loam 共Aeric Epiaqualfs兲
7.2 Crosby OH Spring 112, 180
3.1 Hoytville OH Fall 180 Hoytville silty clay loam 共Mollic Epiaqualfs兲
3.8 Hoytville OH Spring 180
⫺2.2 Scioto OH 1994 Corn Spring Inject 134 AA, UAN Kokomo silty clay loam 共Typic Argiaquolls兲Johnson 1997
8.7 Scioto OH 1995
8.4 Scioto OH 1996
17.6 Germany 1977-81 Various Fall NR 65 ⫺338 Urea Sand-Rosterden Katzur et al. 1984
5.6 Germany 1977-81 Fall,
spring
65 ⫺338
12.9 Germany 1977-81 Spring 65 ⫺338
15.3 Germany 1982-87 Fall 108 ⫺280
21.6 Germany 1982-87 Fall,
spring
108 ⫺280
⫺0.2 Belleville IL 1977 Wheat Fall Incorporate 45, 90, 135 Urea Weir silt loam 共Typic Orchaqualfs兲Liu et al. 1984
27
Table 1. 共Continued兲.
Nitrogen fertilization practice
Relative
effect
共%兲
a
Identity Crop Time Method Rate
共kg ha
–1
兲
Form
b
Soil 共subgroup兲Reference
3.3 Belleville IL 1977 Incorporate 45, 90, 135 UAN
7.0 Belleville IL 1977 Inject 45, 90, 135 AA
12.5 Belleville IL 1979 Incorporate 45, 90, 135 Urea
3.4 Belleville IL 1979 Incorporate 45, 90, 135 UAN
23.0 Belleville IL 1979 Inject 45, 90, 135 AA
5.4 Carbondale IL 1977 Incorporate 45, 90, 135 Urea Stoy silt loam 共Aquic Hapludalfs兲
1.7 Carbondale IL 1977 Incorporate 45, 90, 135 UAN
0.5 Carbondale IL 1977 Inject 45, 90, 135 AA
18.1 Carbondale IL 1979 Incorporate 45, 90, 135 Urea
23.5 Carbondale IL 1979 Incorporate 45, 90, 135 UAN
23.0 Carbondale IL 1979 Inject 45, 90, 135 AA
4.0 Carbondale IL 1980 Incorporate 50, 100, 150 Urea
⫺1.6 Rossville KS 1978 Corn Spring Inject 84, 168, 252 AA Eudora fine sandy loam 共Fleuventic Hapluquolls兲Maddux et al. 1985
0.1 Rossville KS 1979 Fall,
spring
84, 168
⫺1.6 Rossville KS 1979
#III
Spring 84, 168
⫺3.4 Scandia KS 1979 Fall,
spring
84, 168 Crete silty loam 共Pachic Argiustolls兲
10.1 St John KS 1979 Fall,
spring
84, 168 Pratt loamy fine sand 共Psammentic Haplustalfs兲
9.1 Becker MN Corn Spring Incorporate 134 Urea, UAN Hubbard lomy coarse sand 共Udorthentic Hap-
loborolls兲
Malzer 1989
⫺4.5 IA 1987 Spring Inject 157 AA, Urea Webster clay loam 共Typic Hapudolls兲
⫺3.9 MN 1982 Fall,
Spring
Inject 134 AA
⫺0.5 MN #2 1982 Spring Inject, In-
corp
157 ⫺168 AA, UAN,
Urea
Coarse-textured soil
26.7 MN 1982,83 Spring Inject, In-
corp
157 ⫺168 AA, UAN,
Urea
0.0 MN 1983 Spring Inject 134 AA Webster clay loam 共Typic Hapudolls兲
1.3 MN 1985, 86, 87 Spring Inject, In-
corp
157 ⫺168 AA, UAN,
Urea
Coarse-textured soil
20.0 Northern IL 1983 Spring Inject, In-
corp
NR SM Derinda silt loam 共Oxyaquic Hapludalfs兲
10.5 Northern IL 1984 Spring Inject, In-
corp
NR SM
⫺0.1 Northern IL 1985 Spring Inject, In-
corp
NR SM
28
Table 1. 共Continued兲.
Nitrogen fertilization practice
Relative
effect
共%兲
a
Identity Crop Time Method Rate
共kg ha
–1
兲
Form
b
Soil 共subgroup兲Reference
7.5 Northern IL 1986 Spring Inject, In-
corp
NR SM
1.4 WI 1984, 85, 86 Spring Inject, In-
corp
157 ⫺168 AA, UAN,
Urea
Coarse-textured soil
⫺0.3 WI 1987 Spring Inject, In-
corp
134 AA, UAN,
Urea
23.5 Becker MN Spring Incorp 134 Urea Hubbard loamy coarse sand 共Udorthentic Hap-
loborolls兲
15.2 Becker MN Spring Incorp 134 UAN
3.7 West Lafayette IN
1978
Corn Spring Inject 154, 345 SM Chalmers silty clay loam 共Typic Haplaquolls兲McCormick et al. 1984
60.0 West Lafayette IN
1979
Fall 75, 144 SM
1.7 West Lafayette IN
1979
Fall 168 AA
⫺4.3 West Lafayette IN
1979
Spring 161 SM
⫺0.9 West Lafayette IN
1979
Spring 168 AA
27.9 West Lafayette IN
1980
Fall 104, 166 SM
1.4 West Lafayette IN
1980
Fall 168 AA
12.7 West Lafayette IN
1980
Spring 159, 286 SM
11.5 West Lafayette IN
1980
Spring 168 AA
15.6 GA 1978 Sweet
corn
Spring Surface 40 AS ⫹CN Cecil clay loam McElhannon and Mills
1981
19.9 GA 1979
3.2 Marna G MN Corn Fall,
spring
Inject 170, 340 SM Marna silty clay loam 共Typic Hapludolls兲Randall et al. 1999
7.9 Nicollet A MN 64, 127 DM Nicollet clay loam 共Aquic Halludolls兲
0.9 Nicollet C MN 59, 118 DM
7.3 Nicollet E MN 113, 226 SM
⫺2.6 Nicollet F MN 215, 431 SM
3.4 Port Bryan B MN 59, 118 DM Port Bryan silt loam 共Typic Hapludolls兲
0.5 Webster D MN 66, 133 DM Webster clay loam 共Typic Endoaquolls兲
23.9 El Reno OK 1991-94 Wheat Fall Surface 60 Urea Renfrow silt loam, pH 4.8, 1% OC Rao 1996
1.6 El Reno OK 1991-94 Incorporate
29
Table 1. 共Continued兲.
Nitrogen fertilization practice
Relative
effect
共%兲
a
Identity Crop Time Method Rate
共kg ha
–1
兲
Form
b
Soil 共subgroup兲Reference
6.8 Hamerly A MN 1992 Corn Spring Inject 93 DM Hamerly clay loam 共Aeric Calciaquolls兲Schmitt et al. 1995
19.4 Maxcreek C MN
1992
69 DM Maxcreek silty clay loam 共Typic Endoaquolls兲
⫺3.5 Maxfield D MN 1992 119 DM Maxfield silty clay loam 共Typic Endoaquolls兲
⫺2.7 Maxfield F MN 1993 129 SM
⫺5.8 Racine B MN 1992 106 SM Racine silt loam 共Mollic Haplualfs兲
6.5 Schley G MN 1993 80 SM Schley silt loam 共Udollic Ochraqualfs兲
4.1 Webster E MN 1993 63 SM Webster clay loam 共Typic Haplaquolls兲
2.0 Springfield OH 1978 Corn Fall Inject 90, 180 AA Crosby silt loam共Aeric Epiaqualfs兲Stehouwer and Johnson
1990
3.5 Springfield OH 1978 Spring
16.1 Springfield OH 1979 Fall
⫺2.4 Springfield OH 1979 Spring
22.2 Springfield OH 1980 Fall
0.6 Springfield OH 1980 Spring
5.4 Springfield OH 1981 Fall
14.1 Springfield OH 1981 Spring
⫺0.8 Springfield OH 1982 Fall
12.5 Springfield OH 1982 Spring
3.9 Springfield OH 1983 Spring
2.2 Springfield OH 1983 Spring
0.0 Springfield OH 1984 Fall
⫺0.7 Springfield OH 1984 Spring
8.2 Springfield OH 1985 Fall
⫺5.6 Springfield OH 1985 Spring
6.5 Crawfordsville IN
1982
Corn Spring Inject 238 AA ⫹SM Odell silt loam 共Aquic Agridolls兲Sutton et al. 1985, 1986
5.9 Crawfordsville IN
1982
Winter 211
5.1 Crawfordsville IN
1983
Late fall 193
11.7 Crawfordsville IN
1983
Spring 122
5.4 Crawfordsville IN
1984
Late fall 214
⫺0.6 Crawfordsville IN
1984
Spring 271
0.0 Brownstown IL 1976 Corn Fall Inject 67, 134 AA Cisne silt loam 共Mollic Albaqualfs兲Touchton et al. 1979a
⫺0.1 Brownstown IL 1976 Spring
14.6 Urbana IL #2 1976 Corn Fall Incorp 67, 134 Urea Flanagan silt loam 共Typic Hapludolls兲Touchton et al. 1979b
30
Table 1. 共Continued兲.
Nitrogen fertilization practice
Relative
effect
共%兲
a
Identity Crop Time Method Rate
共kg ha
–1
兲
Form
b
Soil 共subgroup兲Reference
⫺2.0 Urbana IL 1975 Spring Inject 67, 134, 268 AA Drummer clay loam 共Typic Haplaquolls兲
⫺12.1 Urbana IL 1976 Fall Inject 67, 134, 268 AA
3.6 Urbana IL 1976 Spring Inject 67, 134, 268 AA
⫺0.1 Bonanza Farm MN
1980
Corn Spring Incorp 90, 180 Urea Estherville sandy loam 共Typic Hapludolls兲Walters and Malzer
1990a
1.5 Bonanza Farm MN
1981
2.2 Bonanza Farm MN
1982
206.9 Sullivan Co. #1 IN
1973
Corn Late fall Inject 134 AA Kings silty clay 共Vertic Endoaquolls兲Warren et al. 1975
1.3 Sullivan Co. #2 IN
1973
200 Elston fine sandy loam 共Typic Agriudolls兲
30.7 Sullivan Co. #2 IN
1974
134, 224
8.7 Pinney #1 IN Corn Fall Inject 83, 166 AA Runnymede loam 共Typic Argiaguolls兲Warren et al. 1980
0.6 Pinney #1 IN Spring 83, 166
18.8 Pinney #2 IN Fall 83, 166 Tracy sandy loam 共Ultic Hapludalfs兲
1.7 Pinney #2 IN Spring 83, 166
9.8 West Lafayette IN Fall 66, 132 Chalmers silty clay loam 共Typic Haplaquolls兲
⫺1.0 West Lafayette IN Spring 66. 132
13.1 Hix IN 1982 Corn Spring Inject 175 DM Blount clay 共Aeric Ochraqualfs兲Welty et al. 1986
2.1 Hix IN 1983 143
21.5 Hix IN 1984 349
⫺16.8 Jackson IN 1982 349
60.9 Jackson IN 1983 349
25.4 Jackson IN 1984 349
⫺0.3 Altus OK 1976 Grain
sorghum
Late
spring
Inject, In-
corp
45, 90, 180 AA, Urea Holister clay loam 共Pachic Paleustolls兲Westerman et al. 1981
⫺0.8 Altus OK 1978 67, 134, 201 UAN
8.4 Altus OK 1979
⫺1.6 Haskell OK 1979 Taloka silt loam 共Mollic Albaqualfs兲
⫺7.4 Tipton OK 1977 Urea, UAN Tipton fine sandy loam 共Pachic Agriustolls兲
3.5 Lewisburg TN 1982 Corn Fall Surface 376 DM Huntington silt loam 共Fluvaquentic Eutrochrepts兲Wolt 1985
4.1 Lewisburg TN 1982 Spring Inject 376 DM
⫺3.9 Lewisburg TN 1982 Spring Incorp 140 AN
14.5 Lewisburg TN 1983 Fall Surface 341 DM
17.4 Lewisburg TN 1983 Spring Inject 341 DM
7.4 Lewisburg TN 1983 Spring Incorp 140 AN
9.1 Blackville SC 1981 Corn Spring Incorp 168 UAN Varina loamy sand 共Plinthic Paleudults兲Zublena 1984
31
scribe an effect on reduced environmental loss of
fertilizer N per se, they are an integrated measure of
N availability during the crop cycle and, therefore, are
directionally indicative of N lost from the agroeco-
system 共increased N availability to the crop represents
N which was not lost from the root zone兲.
Inorganic N in the root zone
In comparison to the database for yield response, that
for inorganic N in the root zone is somewhat more
limited 共50 observations comprising 43 location–
years of experimental results reflecting varied annual
or season-long sampling strategies; Table 2兲. Results
are also more variable, ranging from ⫺39.8 to
135.3%. The grand mean 共⫾standard error兲effect
for nitrapyrin to increase inorganic N retained in the
root zone is 28.2% 共⫾5.4%兲relative to N retention
in the absence of a nitrification inhibitor 共Figure 2兲.
Thirty-nine of 50 observations show a benefit from
nitrapyrin in terms of increased year-long or seasonal
inorganic N retention in the root zone and, conse-
quently, reduced N loss from agroecosystems. These
data largely represent soil N retention during the crop
cycle in which nitrapyrin is applied; therefore, they
do not indicate the long-term fate of seasonally
retained N within the agroecosystem.
N leached from the root zone
The database for N leached from the root zone con-
firms the trend for nitrapyrin application with fertil-
izer or manurial N to increase yield and root zone N
retention 共Table 3兲. Twenty-four observations com-
prising 26 location–years of experimental results de-
scribe N occurrence in percolates or in soil sampled
from below the root zone. As with measurements of
inorganic N within the root zone, these data largely
reflect the leaching of N that occurs within the crop
cycle when a nitrification inhibitor is used. The rela-
tive percent N leached when nitrapyrin was used
ranges from ⫺42.6 to 31.7. The grand mean 共⫾
standard error兲effect is ⫺15.8% 共⫾3.8%兲, indica-
tive of reduced N transport in soil percolates. Nine-
teen of 24 observations show a benefit from nitrapyrin
in terms of decreased year-long or seasonal inorganic
N loss out of the root zone 共Figure 3兲.
Table 1. 共Continued兲.
Nitrogen fertilization practice
Relative
effect
共%兲
a
Identity Crop Time Method Rate
共kg ha
–1
兲
Form
b
Soil 共subgroup兲Reference
6.7 Blackville SC 1982
4.5 Florence SC 1981 Bonneau sand 共Arenic Paleudults兲
⫺3.4 Florence SC 1982 Goldsboro loamy sand 共Aquic Paleudult兲
3.1 Sumter SC 1981 Dothan sandy loam 共Plinthic Paleudults兲
23.0 Sumter SC 1982
a
关共effect with nitrapyrin – effect without nitrapyrin兲⫻100/effect without nitrapyrin兴;
b
AA, anhydrous ammonia; AN, ammonium nitrate; AS, ammonium sulfate; CN, calcium nitrate;
DM, dairy manure, SM, swine manure; UAN, uryl ammonium nitrate.
32
Volatilization of greenhouse gases
A somewhat more limited set of data describes the
relative impact of nitrapyrin use on N loss to the at-
mosphere 共Table 4兲. Nitrapyrin may contribute to re-
duced emission of gases from agricultural soils
through a variety of direct and indirect mechanisms
and, therefore, the nature and the particular volatile
compound that is considered governs the magnitude
of the effect attributed to nitrapyrin. Denitrification
losses of N in the form of N
2
O are the most directly
attributable to inhibition of nitrification, whereas ef-
fects on CH
4
emission will be more indirect through
shifts in microbial processes in the agroecosystems
共13 of the comparisons summarized in Table 4
describe NO
2
efflux and 1 describes CH
4
efflux兲.In
any event, overall these data demonstrate an effect of
nitrapyrin to reduce atmospheric emission of green-
house gases with an overall mean 共⫾standard error兲
effect of ⫺51.2% 共⫾4.0%兲共
Figure 4兲.
Discussion
A large body of literature describes the performance
of nitrification inhibitors in terms of crop response
Figure 1. Frequency distributions describing the relative change in crop yield attributable to nitrification inhibition for comparisons of N
fertilization with and without nitrapyrin 共mean ————; standard error ···············兲.
Figure 2. Frequency distributions describing the relative change in root zone N retention attributable to nitrapyrin for comparisons of N
fertilization with and without nitrapyrin 共mean ————; standard error ···············兲.
33
and N fate within agronomic ecosystems. Consider-
able variability in response is reported from individ-
ual research findings and is anticipated based on the
numerous crop, environment, and management fac-
tors that in combination contribute variability to the
processes whereby N is cycled and utilized within
crop production systems. When described in terms of
relative responses among diverse experiments, indi-
ces of N loss indicate a consistent effect of nitrifica-
tion inhibitor use in conjunction with N fertilization.
The distributions of effects when compared across
various indices of N loss 共Figure 5兲show that for
ⱖ75% of the comparisons considered, nitrapyrin in-
creased annual or season-long N retention in the crop
root zone, increased crop yield, decreased N leaching
from the root zone, and decreased volatilization of
greenhouse gases.
On a regional basis over time, factors such as ni-
trogen fertilization practice 共rate, timing, source,
placement兲, soil factors 共texture, organic matter con-
tent, pH兲, and environmental conditions 共soil cover,
temperature, moisture兲combine to influence the
overall performance of a nitrification inhibitor. The
integrated effect of these factors on nitrapyrin
performance is represented by the meta-evaluation of
diverse studies that in combination describe the an-
ticipated effect of sustained use of nitrification inhibi-
tors in a region over time. The observed variance in
Figure 3. Frequency distributions describing the relative change in N leached from the root zone attributable to nitrapyrin for comparisons of
N fertilization with and without nitrapyrin 共mean ————; standard error ···············兲.
Figure 4. Frequency distributions describing the relative change in greenhouse gas emissions attributable to nitrapyrin for comparisons of N
fertilization with and without nitrapyrin 共mean ————; standard error ···············兲.
34
Table 2. Relative amount of inorganic N retained within the crop root zone as affected by nitrapyrin applied with sources of fertilizer or manurial N.
Nitrogen fertilization practice
Relative
effect 共%兲
a
Identity Crop Time Method Rate
共kg ha
–1
兲
Form
b
Soil 共subgroup兲Reference
15.8 Marengo IA 1986 Corn Spring Incorporate 56, 112,
178
AS Nevin 共Aquic Agriudolls兲Cerrato and Blackmer
1990
⫺0.9 Kalona IA 1986 Bremer 共Typic Agriaquolls兲
4.9 Ames #1 IA 1986 Nicollett 共Aquic Hapludolls兲
5.7 Ames #2 IA 1986 Canisteo 共Typic Haplaquolls兲
6.0 Ida Grove IA 1986 Marshall 共Typic Hapludols兲
⫺1.7 Holestein IA 1986 Galva 共Typic Hapludolls兲
21.5 Narrabri #1 NSW Uncropped Fall Incorporate 120 Urea Fine-textured grey clay 共Typic Pellusterts兲Chen et al. 1994
31.8 Narrabri #2 NSW
84.7 Buffalo ND 1997 Wheat Fall Inject 84 AA Gardena loam 共Pachic Hapludolls兲Goos and Johnson 1999
38.7 Fargo ND 1997 Fargo silty clay 共Typic Epiaquerts兲
⫺2.0 Benerembah NSW Rice Incorporate 80 Urea Grey clay 共Typic Pelloxererts兲Keerthisinghe et al.
1993
35.4 Columbia, MO 91 Wheat Fall Inject 56, 112 AA Mexico silt loam 共Udollic Ochraqualf兲Kidwaro and Kephart
1998
19.5 Columbia, MO 92
⫺8.7 Bellville IL 1977 Wheat Fall Incorporate 152 Urea Weir silt loam 共Typic Orchaqualfs兲Liu et al. 1984
⫺18.2 UAN
115.7 Bellville IL 1979 100, 151 Urea
78.9 UAN
17.3 Carbondale IL 1980 112 Urea Stoy silt loam 共Aquic Hapludalfs兲
46.3 Rossville KS 1979 #III Corn Spring Inject 84, 168,
260
AA Eudora fine sandy loam 共Fleuventic Haplu-
quolls兲
Maddux et al. 1985
111.5 West Lafayette IN 1979 Fallow Spring Inject 157 SM Chalmers silty clay loam 共Typic Haplaquolls兲McCormick et al. 1983
⫺3.5 Edinburgh UK Grassland Spring Surface 120 AS, Urea Winton clay loam McTaggart et al. 1997
38.5 Nicollet A MN Corn Fall, spring Inject 116, 234 DM Nicollet clay loam 共Aquic Hapludolls兲Randall et al. 1999
41.2 Port Bryan B MN 108, 215 Port Bryan silt loam 共Typic Hapludolls兲
11.1 Nicollet C MN Nicollet clay loam 共Aquic Halludolls兲
13.8 Webster D MN 121, 241 Webster clay loam 共Typic Endoaquolls兲
⫺3.5 Nicollet E MN 175, 350 SM Nicollet clay loam 共Aquic Hapludolls兲
15.5 Nicollet F MN 331, 662
7.2 Marna G MN 262, 524 Marna silty clay loam 共Typic Hapludolls兲
135.3 El Reno OK 1991 Wheat Fall Surface,
incorp.
60 Urea Renfrow silt loam 共Udertic Paleustolls兲Rao 1996
32.3 El Reno OK 1992
36.9 El Reno OK 1993
6.5 El Reno OK 1994
7.1 Northwest IL 1986 #1 Corn Spring Inject 302 BM Derinda silt loam Oxyaquic Haplualfs兲Sawyer et al. 1990
65.6 Northwest IL 1986 #2
20.1 Crawfordsville IN 1982 Corn Fall Inject 235 AA ⫹SM Odell silt loam 共Aquic Agridolls兲Sutton et al. 1986
35
Table 2. 共Continued兲.
Nitrogen fertilization practice
Relative
effect 共%兲
a
Identity Crop Time Method Rate
共kg ha
–1
兲
Form
b
Soil 共subgroup兲Reference
10.4 Crawfordsville IN 1983 228
22.3 Crawfordsville IN 1983 183
⫺0.2 Crawfordsville IN 1982 Spring 295
⫺16.7 Crawfordsville IN 1983 133
⫺39.8 Crawfordsville IN 1983 239
55.3 Urbana IL 1975 Corn Fall Inject 67, 134 AA Drummer silty clay loam 共Typic Haplaquolls兲Touchton et al. 1978a
93.0 Urbana IL 1976 Spring
14.0 Urbana IL 1975 Spring
⫺7.1 Brownstown IL 1976 Spring
73.4 Fall
11.2 Bonanza Farm MN
1980
Corn Spring Incorporate 90, 180 Urea Estherville sandy loam 共Typic Hapludolls兲Walters and Malzer
1990b
104.6 Bonanza Farm MN
1981
52.4 Altus OK 1976 Grain sor-
ghum
Spring Incorporate,
inject
45, 90, 180 AA Holister clay loam 共Pachic Paleustolls兲Westerman et al. 1981
7.1 Tipton OK 1977 67, 134,
202
Urea, UAN Tipton fine sandy loam 共Pachic Agriustolls兲
2.7 Altus OK 1978 UAN Holister clay loam 共Pachic Paleustolls兲
a
关共effect with nitrapyrin – effect without nitrapyrin兲⫻100/effect without nitrapyrin兴;
b
AA, anhydrous ammonia; AS, ammonium sulfate; BM, beef manure; DM, dairy manure, SM, swine
manure; UAN, uryl ammonium nitrate.
36
Table 3. Relative quantity of N leached from the crop root zone as affected by nitrapyrin applied with sources of fertilizer or manurial N.
Nitrogen fertilization practice
Relative effect
共%兲
a
Identity Crop Time Method Rate
共kg ha
–1
兲
Form
b
Soil 共subgroup兲Reference
⫺20.6 Germany 1977-81 Various Spring NR Various Urea Sand-Rosterden Katzur and Zietz 1984
⫺29.9 Fall
⫺17.6 Fall,
Spring
⫺22.6 Germany 1982-87 Various Spring NR Various Urea Sand-Rosterden Katzur et al. 1984
⫺15.8 Fall
⫺12.1 Fall,
Spring
15.5 Coshocton OH 1977-78 Corn Spring Incorpo-
rate
300 Urea Rayne silt loam 共Typic Hapludults兲Owens 1987
⫺8.4 Coshocton OH 1978-79
⫺16.5 Coshocton OH 1979-80
⫺42.1 Coshocton OH 1980-81
⫺35.3 Coshocton OH 1981-82
⫺24.5 Coshocton OH 1982-83
⫺25.4 Coshocton OH 1983-84 Wheat, rye
⫺40.4 Hurley UK Perennial
ryegrass
Winter Inject 221 DM Frilsam loam Thompson et al. 1987
⫺42.6 Huley UK Spring 234
⫺10.7 Lab column #1 None N/A Surface 200 AA Estherville sandy loam 共Typic Haplu-
dolls兲
Timmons 1984
31.7 Lab column #2 Urea
⫺23.7 Westport MN 1977 Corn Spring Incorpo-
rate
Urea
⫺2.5 Westport MN 1978
11.8 Wesport MN 1979
1.6 Bonanza Farm MN 1980 Corn Spring Incorpo-
rate
80 & 160 Urea Estherville sandy loam 共Typic Haplu-
dolls兲
Walters and Malzer
1990b
1.0 Bonanza Farm MN 1981
⫺24.5 Olmsted Co. MN Corn Various NR Various Vari-
ous
NR Yadav 1997
⫺25.4 Goodhue Co. MN
a
关共effect with nitrapyrin – effect without nitrapyrin兲⫻100/effect without nitrapyrin兴;
b
AA, anhydrous ammonia; DM, dairy manure.
37
Table 4. Relative amount of greenhouse gas forced from agricultural soils as affected by nitrapyrin applied with sources of fertilizer or manurial N.
Nitrogen fertilization practice
Relative
effect 共%兲
a
Identity Crop Time Method Rate
共kg ha
–1
兲
Form
b
Soil 共subgroup兲Reference
⫺51.9 Ames IA 1979 Fallow Fall Injection 180 AA Webster clay loam 共Typic Haplaquolls兲Bremner et al. 1981
⫺59.9 Ames IA 1980 Spring
⫺65.1 Ft Collins CO 1989 #1 Corn Early sum-
mer
Incorporated 195 Urea Nunn clay loam 共Aridic Argiustolls兲Bronson et al. 1992
⫺65.6 Ft Collins CO 1989 #2
⫺40.6 Ft Collins CO 1990
⫺27.4 Benerembah NSW Dry-seeded
flooded rice
Incorporated 0 & 71 Urea Grey clay 共Typic Pelloxererts兲Keerthisinghe et al. 1993
⫺69.8
⫺56.9 Hurley UK Perennial
ryegrass
Winter Inject 221 DM Frilsam loam Thompson et al. 1987
⫺20.9 Spring 234
⫺58.8 Darling Downs QLD
1982 #1
Fallow Spring Injection 80 AA Mywybilla clay 共Typic Pellusterts兲Magalhaes et al. 1984
⫺66.0 Darling Downs QLD
1982 #2
60 Anchorfield clay 共Typic Chromus-
tersts兲
⫺51.8 Darling Downs QLD
1982 #3
Norilee clay 共Typic Chromusterts兲
⫺38.1 Edinburgh UK Grassland Spring Surface 120 AS, Urea Winton clay loam McTaggart et al. 1997
⫺44.2 GA 1979 Sweet corn Spring Surface 40 AS ⫹CN Cecil clay loam 共Typic Kanhapludults兲McElhannon and Mills
1981
a
关共effect with nitrapyrin – effect without nitrapyrin兲⫻100/effect without nitrapyrin兴;
b
AA, anhydrous ammonia; AS, ammonium sulfate; CN, calcium nitrate; DM, dairy manure;
c
N
2
O.
d
CH
4
.
38
the response elements considered reflects the varied
source data representing a wide range of environ-
ments and management scenarios where a nitrifica-
tion inhibitor may be used. Conditions of use
including fertilizer timing, source, and placement as
well as environmental properties such as soil cover,
temperature, and moisture content affect the physico-
chemical and biological performance of the nitrifica-
tion inhibitor 共Wolt 1999兲as well as the overall
nitrogen cycle.
In approximately 25% of the instances considered,
use of a nitrification inhibitor did not positively affect
agronomic or environmental performance. These in-
stances may represent situations where environmen-
tal conditions were not conducive to N losses from
the agroecosystem 共Blackmer and Sanchez 1988兲,or
they may represent situations where nitrification in-
hibitor use in conjuction with fertilization practice re-
sults in N loss through ammonia volatilization
共Thompson et al. 1987兲. Examples of the latter would
be fertilization strategies involving N forms 共urea or
ammonium fertilizers兲, placements 共surface applica-
tion兲, and timings 共fall applications兲as well as pro-
longed periods where soils are warm and moist,
allowing for ammonia volatilization 共Brink et al.
2000; Harrison and Webb 2001兲. As a consequence,
the positive aspects of nitrification inhibition in
reducing N leaching and reduced greenhouse gas
evolution must be balanced against the potential
negative effects of environmental acidification
through soil ammonia efflux.
This analysis has considered the agronomic and
environmental effectiveness of nitrapyrin, a widely
studied product with a long history of use for nitro-
gen inhibition in the intense corn production regions
of the Midwestern USA. Nitrapyrin is representative
of a broad class of compounds that act as nitrification
inhibitors and that appear to affect the initial rate lim-
iting step of nitrification involving NH
4
⫹
oxidation:
2NH4
⫹⫹3O2→
Nitrosomonas
2NO2
⫺⫹4H⫹⫹2H2O.
Alternative forms of nitrification inhibitors 共for ex-
ample, dicyandiamide, ammonium thiosulfate, and
etridiazol兲can be expected to have similar relative
responses as has been considered here for nitrapyrin.
The performance of any of these, as compared to ni-
trapyrin, will vary dependent on considerations of
physico-chemical properties, efficacy, and persistence
in various environments and management regimes.
For instance, comparative differences in field per-
formance of different nitrification inhibitors have
been attributed to physical 共volatility兲and biological
共efficacy and persistence兲properties as affected by
factors such as surface cover, timing of application,
and method of placement 共Malzer 1989; McTaggart
et al. 1997; Goos and Johnston 1999兲.
Figure 5. Comparative distribution of nitrapyrin effect, expressed as relative percent of the change attributable to nitrapyrin, for four indices
of N mobility. Box plots represent the 10, 25, 50, 75, and 90
th
percentile effect with mean 共dotted line兲and outliers 共upper and lower 10
percentile of distribution兲.
39
Conclusions
A comprehensive assessment of nitrapyrin effect on
indices of N loss from agricultural ecosystems shows
that despite the anticipated variability in response
there is a positive impact on N use efficiency and
consequently N loss when viewed from the perspec-
tive of impact within a region over time. These find-
ings are of special consequence to the potential for
nitrification inhibitors to be effectively employed for
mitigating the adverse consequences of N loss from
soils receiving inputs of N fertilizer or manure. Field
research to date has focused primarily on the impact
of nitrification inhibition at the agronomic scale over
rather short timeframes, whereas the potential benefits
of nitrification inhibitor use in relation to N loss to
ground and surface water or to the atmosphere need
to be considered at the scale of a sensitive region,
such as a watershed, over a prolonged period of use.
The results reported here suggest that nitrification in-
hibition when considered within this context can
positively contribute to reduced NO
3
and greenhouse
gas losses from agricultural lands. These benefits
must be considered within the context of overall goals
for abatement of N losses through agricultural best
management practices.
References
Arif M.A.S., Houwen F. and Verstraete W. 1996. Agricultural fac-
tors affecting methane oxidation in arable soil. Biol. Fert. Soils
21: 95–102.
Blackmer A.M. and Sanchez C.A. 1988. Response of corn to ni-
trogen-15-labeled anhydrous ammonia with and without nitrapy-
rin in Iowa. Agron. J. 80: 95–102.
Bremner J.M., Breitenbeck G.A. and Blackmer A.M. 1981. Effect
of nitrapyrin on emission of nitrous oxide from soil fertilized
with anhydrous ammonia. Geophys. Res. Lett. 8: 353–356.
Brink J.C., Hordijk K.L., van Ierland E.C. and Kroeze C. 2000.
Cost-effective N
2
O, CH
4
and NH
3
abatement in European agri-
culture: Interrelations between global warming and acidification
policies. Expert Workshop on Assessing the Ancillary Benefits
and Costs of Greenhouse Gas Mitigation Strategies, 27–29
March 2000, Washington, DC, USA.
Bronson K.F., Mosier A.R. and Bishnoi S.R. 1992. Nitrous oxide
emissions in irrigated corn as affected by nitrification inhibitors.
Soil Sci. Soc. Am. J. 56: 161–165.
Bronson K.F. and Mosier A.R. 1993. Effect of N fertilizer and ni-
trification inhibitors on methane and nitrous oxide fluxes in irri-
gated corn. In: Oremland R.S. 共ed.兲, Biogeochem. Global
Change Sel. Pap. Int. Symp. Enviro. Biogeochem., 10
th
共1993兲,
Meeting date 1991. Chapman & Hall, New York, pp. 278–289.
Cerrato M.E. and Blackmer A.M. 1990. Effects of nitrapyrin on
corn yields and recovery of ammonium-N at 18 site-years in
Iowa. J. Prod. Agric. 3: 513–521.
Chen D.L., Freney J.R., Mosier A.R. and Chalk P.M. 1994. Reduc-
ing denitrification loss with nitrification inhibitors following
presowing application of urea to a cottonfield. Aust. J. Exp. Ag-
ric. 34: 75–83.
Dow AgroSciences 1999. Specimen Label: N-serve Nitrogen Sta-
bilizer, D02-011-013. Dow AgroSciences LLC, Indianapolis, IN.
Frye W.W., Blevins R.L., Murdock L.W., Wells K.L. and Ellis J.H.
1981. Effectiveness of nitrapyrin with surface-applied fertilizer
nitrogen in no-tillage corn. Agron. J. 73: 287–289.
Goos R.J. and Johnson B.E. 1999. Performance of two nitrification
inhibitors over a winter with exceptionally heavy snowfall.
Agron. J. 91: 1046–1049.
Harrison R. and Webb J. 2001. A review of the effect of N fertil-
izer type on gaseous emissions. Adv. Agron. 73: 65–108.
Huber D.M., Sutton A.L., Jones D.D., Joern B.C. and Mitchell J.K.
1993. Nutrient management of manure to enhance crop produc-
tion and protect the environment. In: Integrated resource man-
agement and landscape modification for environmental protec-
tion. Proceedings of the International Symposium. Chicago, IL,
13–14 December, 1993. American Society of Agricultural Engi-
neers, St Joseph, MI, pp. 39–45.
Huber D.M., Warren H.L., Nelson D.W., Tsai C.Y. and Shaner G.E.
1980. Response of winter wheat to inhibiting nitrification of
fall-applied nitrogen. Agron. J. 72: 632–637.
Johnson J.W. 1995. Nitrification inhibitors potential use in Ohio.
AGF-201-95. Ohio State University Extension, Columbus, OH.
Accessed electronically 3 December 2002, http://ohioline.os-
u.edu/ag-fact/0201.html
Johnson J.W. 1997. Influence of nitrapyrin on nitrate concentration
in soils. Proceedings 27th North Central Extension-Industry Soil
Fertility Conference 19–20 November 1997, St. Louis, MO, pp.
67–69.
Katzur J., Hoffmann E. and Tolle R. 1990. Zur Ertragswirksamkeit
der Nitrifizide und Strohdungung. Arch. Acker- Pflanzenbau
Bodenk. 34共5兲: 317–327.
Katzur J., Tölle R. and Hoffmann E. 1989. Langzeituntersuchun-
gen zur N-auswaschungsmindernden Wirkung der Nitrifizide bei
Harnstoffdüngung in grundwasserfreien Lysimetern ohne Unter-
druck. Arch. Acker- Pflanzenbau Bodenk. 33共3兲: 147–157.
Katzur J. and Zeitz J. 1984. Fünfjährige Ergebnisse uber den Ein-
fluß von N-Serve und Strohdüngung auf die Stickstoffaus-
waschung. Arch. Acker- Pflanzenbau Bodenk. 28共4兲: 239–245.
Kidwaro F.M. and Kephart K.D. 1998. Retention of nitrogen from
stabilized anhydrous ammonia in the soil profile during winter
wheat production in Missouri. Commun. Soil Sci. Plant Anal. 29:
481–499.
Keerthisinghe D.G., Freney J.R. and Mosier A.R. 1993. Effect of
wax-coated calcium carbide and nitrapyrin on nitrogen loss and
methane emission from dry-seeded flooded rice. Biol. Fert. Soils
16: 71–75.
Kenney D.R. 1980. Factors affecting the persistence and bioactiv-
ity of nitrification inhibitors. In: Meisinger J.J., Randall G.W.
and Vitosh M.I. 共eds兲, Nitrification Inhibitors ⫺Potential and
Limitations. ASA Special Publication 38, American Society of
Agronomy, Madison, WI, Chapter 3, pp. 33–46.
40
Liu S.L., Varsa E.C., Kapusta G. and Mburu D.N. 1984. Effect of
etridiazol and nitrapyrin treated N fertilizers on soil mineral N
status and wheat yields. Agron. J. 76: 265–270.
Maddox L.D., Kissel D.E., Ball J.D. and Raney R.J. 1985. Nitrifi-
cation inhibition by nitrapyrin and volatile sulfur compounds.
Soil Sci. Soc. Am. J. 49: 239–242.
Magalhaes A.M.T., Chalk P.M. and Strong W.M. 1984. Effect of
nitrapyrin on nitrous oxide emission from fallow soils fertilized
with anhydrous ammonia. Fert. Res. 5: 411–421.
Malzer G.L. 1989. Incorporation of nitrification inhibitors with
urea and urea-ammonium nitrate for irrigated corn. Fert. Res. 18:
141–151.
Malzer G.L., Kelling K.A., Schmitt M.A., Hoeft R.G. and Randall
G.W. 1989. Performance of dicyanamide in the North Central
states. Commun. Soil Sci. Plant Anal. 20: 2001–2022.
McCormick R.A., Nelson D.W., SuttonA.L. and Huber D.M. 1983.
Effect of nitrapyrin on nitrogen transformations in soil treated
with liquid swine manure. Agron. J. 75: 947–950.
McCormick R.A., Nelson D.W., SuttonA.L. and Huber D.M. 1984.
Increased N efficiency from nitrapyrin added to liquid swine
manure used as a fertilizer for corn. Agron. J. 76: 1010–1014.
McElhannon W.S. and Mills H.A. 1981. Inhibition of denitrifica-
tion by nitrapyrin with field-grown sweet corn. J. Am. Soc. Hort.
Sci. 106: 673–677.
McTaggart I.P., Clayton H., Parker J., Swan L. and Smith K.A.
1997. Nitrous oxide emissions from grassland and spring barley
following N fertilizer application with and without nitrification
inhibitors. Biol. Fert. Soils 25: 261–268.
Meisinger J.J., Randall G.W. and Vitosh M.I. 共eds兲1980. Nitrifi-
cation Inhibitors – Potential and Limitations. ASA Special Pub-
lication 38, American Society of Agronomy, Madison, WI.
Nelson D.W. and Huber D.M. 1980. Performance of nitrification
inhibitors in the Midwest 共east兲. In: Meisinger J.J., Randall G.W.
and Vitosh M.I. 共eds兲, Nitrification Inhibitors – Potential and
Limitations. ASA Special Publication 38, American Society of
Agronomy, Madison, WI, Chapter 6, pp. 75–88.
Owens L.B. 1987. Nitrate leaching losses from monolith lysimeters
as influenced by nitrapyrin. J. Environ. Qual. 16: 34–38.
Randall G.W. 2000. N management and its influence on N losses
to surface water through subsurface tile lines. In: Potash and
Phosphate Institute 共ed.兲, Proceedings 30
th
North Central Exten.
– Ind. Soil Fert. Conference. Vol. 16, Nov. 15–16, 2000, St.
Louis, MO, p. 29.
Randall G.W., Schmitt M.A. and Schmidt J.P. 1999. Corn produc-
tion as affected by time and rate of manure application and ni-
trapyrin. J. Prod. Agric. 12: 317–323.
Rao S.C. 1996. Evaluation of nitrification inhibitors and urea
placement in no-tillage winter wheat. Agron. J. 88: 904–908.
Robertson G.P., Paul E.A. and Harwood R.R. 2000. Greenhouse
gases in intensive agriculture: contributions of individual gases
to the radiative forcing of the atmosphere. Science 289: 1922–
1925.
Sawyer J.E., Schmitt M.A. and Hoeft R.G. 1990. Inorganic nitro-
gen distribution and soil chemical transformations associated
with injected liquid beef manure. Agron. J. 82: 963–969.
Schmill M.A., Evans S.D. and Randall G.W. 1995. Effect of liquid
manure application methods on soil nitrogen and corn grain
yields. J. Prod. Agric. 8: 186–189.
Stehouwer R.C. and Johnson J.W. 1990. Urea and anhydrous am-
monia management for conventional tillage corn production. J.
Prod. Agric. 3: 507–513.
Sutton A.L., Huber D.M., Jones D.D., Kelly D.T. and Bache D.H.
1986. Use of nitrification inhibitors and ammonia enrichment
with swine manure application. Appl. Engin. Agric. 2: 179–185.
Sutton A.L., Huber D.M., Jones D.D., Kelly D.T. and Bache D.H.
1985. Use of nitrification inhibitors and ammonia enrichment
with swine manure applications. In ASAE SP 13-85. American
Society of Agricultural Engineers, St. Joseph, MI, pp. 240–248.
Thompson R.B., Ryden J.C. and Lockyer D.R. 1987. Fate of N in
cattle slurry following surface application or injection to grass-
land. J. Soil Sci. 38: 689–700.
Timmons D.R. 1984. Nitrate leaching as influenced by water ap-
plication level and nitrification inhibitor. J. Environ. Qual. 13:
305–310.
Touchton J.T., Hoeft R.G. and Welch L.F. 1978a. Effect of nitrapy-
rin on nitrification of fall and spring-applied anhydrous ammo-
nia. Agron. J. 70: 805–810.
Touchton J.T., Hoeft R.G. and Welch L.F. 1978b. Nitrapyrin deg-
radation and movement in soil. Agron. J. 70: 811–816.
Touchton J.T., Hoeft R.G. and Welch L.F. 1979a. Effect of nitrapy-
rin on nitrification of broadcast-applied urea, plant nutrient con-
centrations, and corn yield. Agron. J. 71: 787–791.
Touchton J.T., Hoeft R.G., Welch L.F., Mulvaney D.L., Oldham
M.G. and Zajicek F. E. 1979b. N uptake and corn yield as af-
fected by applications of nitrapyrin with anhydrous ammonia.
Agron. J. 71: 238–242.
Walters D.T. and Malzer G.L. 1990a. Nitrogen management and
nitrification inhibitor effects on nitrogen-15 urea: I. Yield and
fertilizer use efficiency. Soil Sci. Soc. Am. J. 54: 115–122.
Walters D.T. and Malzer G.L. 1990b. Nitrogen management and
nitrification inhibitor effects on nitrogen-15 urea: II. Nitrogen
leaching and balance. Soil Sci. Soc. Am. J. 54: 122–130.
Warren H.L., Huber D.M., Nelson D.W. and Mann O.W. 1975.
Stalk rot incidence and yield of corn as affected by inhibiting
nitrification of fall-applied ammonium. Agron. J. 67: 655–660.
Warren H.L., Huber D.M., Tsai C.Y. and Nelson D.W. 1980. Effect
of nitrapyrin and N fertilizer on yield and mineral composition
of corn. Agron. J. 72: 729–732.
Welty D.L., SuttonA.L., Nye J.C., Jones D.D. and Kelly D.T. 1986.
Fertilizer value of swine and dairy manure from an above-
ground liquid manure storage system. Appl. Engin. Agric. 2:
206–214.
Westerman R.L., Edlund M.G. and Minter D.L. 1981. Nitrapyrin
and etradiazole effects on nitrification and grain sorghum pro-
duction. Agron. J. 73: 697–702.
Wolt J.D. 1985. Utilization of organic wastes on agricultural soils
of Tennessee. Univ. Tenn. Agric. Exp. Sta. Bull. 638.
Wolt J.D. 2000. Nitrapyrin behavior in soils and environmental
considerations. J. Environ. Qual. 29: 367–379.
Yadav S.N. 1997. Formulation and estimation of nitrate-nitrogen
leaching from corn cultivation. J. Environ. Qual. 26: 808–814.
Zublena J.P. 1984. Corn response to nitrapyrin and N-application
methods on sandy Coastal Plain soils. Fert. Issues 1共1兲: 7–14.
41
