Table Of ContentOTHER TITLES IN THIS SERIES
1. Plant Modification for More Efficient Water Use
by J.F. Stone (Editor)
1975 x +320 pp.
2. Tree Ecology and Preservation
by A. Bernatzky
1978viii + 358pp.
3. Cycling of Mineral Nutrients in Agricultural Ecosystems
by M.J. Frissel (Editor)
1978viii + 356pp.
4. Interactions Between Non-Pathogenic Soil Microorganisms and Plants
by Y.R. Dommergues and S.V. Krupa (Editors)
1978xii + 476pp.
5. Ecology of Root Pathogens
by S.V. Krupa and Y.R. Dommergues (Editors)
1979 x + 282 pp.
6. Soil Disinfestation
byD. Mulder (Editor)
1979 xiv-I-368 pp.
7. Management of Semi-air Ecosystems
by B.H. Walker (Editor)
1979 x + 398 pp.
8. Management and Analysis of Biological Populations
byB.S. Goh
1980 x-I-288 pp.
9. Comparison of Forest Water and Energy Exchange Models
byS.Halldin (Editor)
1979xi + 258 pp.
10. Alternative Methods of Agriculture
byR. Boeringa (Editor)
1980 vi +200 pp.
11. Wetlands of Bottomland Hardwood Forest
by J.R. Clark and J. Benforado (Editors)
1981 xviii + 402 pp.
12. Plant Production and Management under Drought Conditions
by J.F. Stone and W.O. Willis (Editors)
1983vii + 390pp.
13. Evapotranspiration from Plant Communities
by M.L. Sharma (Editor)
1984 vii-I-344 pp.
14. Forest Amelioration
byO. Riedl and D. Zachar
1984viii + 624pp
15. Floodplain Forest Ecosystem
byM. Penka, M. Vyskot, E. Klimoand F. VasiCek
Part I. Before Water Management Measures
1985xii + 468pp.
Part II. After Water Management Measures
in preparation
16. The Origin and Domestication of Cultivated Plants
byC. Barigozzi (Editor)
1986vi + 218pp.
17. Soil Microbial Associations
byV. VanCura and F. Kunc (Editors)
1988 498 pp.
18. Tree Crop Physiology
by MR. Sethuraj and A.S. Raghavendra (Editors)
1987xii + 361 pp.
19. Towards a Second Green Revolution
by G.B. Marini-Bettolo (Editor)
1988xii + 530pp.
20. Shrub-Steppe. Balance and Change in a Semi-Arid Terrestrial Ecosystem
by W.H. Rickard, L.E. Rogers, BE. Vaughan and S.F. Liebetrau (Editors)
1988xii + 272pp.
DEVELOPMENTS IN AGRICULTURAL
AND MANAGED-FOREST ECOLOGY 21
nitrogen
management
and
ground water protection
Edited by
R.F. FOLLETT
USDA-ARS, Northern Plains Area, 301 South Howes, P.O. Box E, Fort Collins,
CO 80522, U.S.A.
ELSEVIER
Amsterdam — Oxford — New York — Tokyo 1989
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©Elsevier Science Publishers B.V., 1989
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Printed in The Netherlands
X
PREFACE
The N cycle in soil is an integral part of the overall cycle of N in
nature. Under natural conditions, gains in soil N occur through N fixation
and from the return of ammonia and nitrate in precipitation. Nitrogen losses
occur through crop removal, leaching, gaseous losses, and by transport during
soil erosion and surface water runoff. Adequate amounts of plant available N
in soil are vital to ensuring the production of sufficient food for the
world's population. To enhance its availability for crop growth, N is added
to the soil in which crops are grown. Sources of N for addition to soil
include fertilizer, crop residue, manure and various other waste materials,
and biological N fixation. Once N from any of these sources, including from
natural sources, enters the soil it is subject to the chemical transformations
that occur in the N cycle in the soil (i.e. immobilization, mineralization,
nitrification, and denitrification). If cultural practices, including
excessive additions of N to soils, result in the accumulation of nitrate N in
the soil, then a situation may be set up that results in the leaching of
nitrate by water percolating through the soil profile. Thus, in assuring
availability of N to plants for crop production, it is becoming increasingly
apparent that a higher level of management will be necessary to prevent or
minimize the contamination of ground water and surface water supplies.
The authors of chapters in this volume have undertaken the task of placing
in perspective the overall problem of the management of nitrogen in producing
food while also minimizing impacts to ground water quality. I consider it a
great privilege to have had the opportunity to work directly with each of the
authors of this volume. Certainly they have given their best effort to
organize and present the information herein and have my sincerest
appreciation. I also want to express appreciation to Professor R.A. Olson,
"Profw to so many who knew him, who was to have worked on this project with
me. Without his encouragement and input while the project was being planned,
it would have been much less successful. I deeply regret that he did not have
the opportunity to complete this project with me nor to see the final work.
Therefore, this book is dedicated to R.A. Olson, Professor Emeritus -
University of Nebraska.
RONALD F. FOLLETT, editor
USDA-ARS, Fort Collins, CO
XI
DEDICATION
ROBERT A. OLSON
This book is dedicated to Professor Robert A. Olson, internationally
recognized soil scientist, who was among the first to point out the
environmental consequences of the mismanagement of nitrogen fertilizers. He
was one of the first scientists to use radioisotopes to evaluate nutrient
uptake by crops and was a world authority on applications of radio tracer
methods in agricultural research. He served with the International Atomic
Energy Agency in 1962 and 197*1-75 and with the Food and Agriculture
Organization from 1967-69 because of his specialized knowledge of tracer
methodology.
Professor Olson was a faculty member of the university of Nebraska for 38
years. During this period, every undergraduate Agronomy major completed his
"Fertilizer Technology and Use" and many enrolled in his "Introductory Soils"
and "Soil Management" courses. He advised 15 doctoral, kl master's and 9
postdoctoral students during his career. Professor Olson published more than
100 journal articles, 21 book chapters and countless numbers of semi-technical
articles for producers. Most of his research was concerned with efficient use
of fertilizers, with major emphasis in recent years on nitrogen management.
His excellence in research and teaching was widely recognized and as a result,
he received numerous awards from the American Society of Agronomy (Fellow,
Agronomic Research Award, International Agronomy Award, and Agronomic
Achievement Award-Soils) and the Soil Science Society of America (Fellow, Soil
Science Award, and Bouyoucous Soil Science Distinguished Career Award) and the
University of Nebraska (Distinguished Teaching Award).
Professor Olson's research in the 1950fs was a major factor in encouraging
nitrogen fertilizer use by farmers in the western Cornbelt. Through careful
studies conducted throughout Nebraska, he showed that the residual nitrate in
the soil profile had a great effect on the nitrogen fertilizer needs of corn.
He also showed that the addition of nitrogen fertilizer in excess of that
required for the crop will result in loss of nitrate from the root zone by
leaching. The results of these studies were published in the early 1960fs.
Throughout the remainder of Professor Olson's career, he studied nitrogen use
efficiency as affected by placement and timing of nitrogen fertilizers,
irrigation water management, and cropping practices. These studies provide
XII
much of the basis for the wbest management practices" currently recommended to
minimize nitrate contamination of ground water.
It is highly fitting that this book be dedicated to Professor Robert A.
Olson, a soil scientist who was equally concerned with the efficiency of crop
production and environmental quality. "Prof" Olson was both a prophet in
foretelling the consequences of improper nitrogen use and a pioneer in the
development and dissemination of management practices which increase
utilization of nitrogen by crops and minimize environmental impacts.
DARRELL W. NELSON
Dean and Director
Agricultural Research Division
University of Nebraska
Lincoln, NE
XIII
Professor Robert A. Olson (1917-1987)
XIV
CONTRIBUTORS
D. W. Nelson J. F. Power
Dean and Director Agricultural Research Service/USDA
Agricultural Research Division University of Nebraska
University of Nebraska Keim Hall, East Campus
Lincoln, NB 68583 Lincoln, NE 68583
R. F. Follett F. E. Broadbent
Agricultural Research Service/USDA Deptartment of Land, Air,
P.O. Box E., Federal Building and Water Resource
301 South Howes Hoagland Hall
Fort Collins, CO 80522 University of California
Davis, CA 95616
D. J. Walker
Department of Agricultural G. A. Peterson
Economics and Rural Sociology Department of Agronomy
University of Idaho Colorado State University
Moscow, ID 83843 Fort Collins, CO 80523
D. Keeney W. W. Frye
Leopold Center for Department of Agronomy
Sustainable Agriculture University of Kentucky
Iowa State University Lexington, KY 40506
Ames, IA 50011
J. S. Schepers
G. R. Hallberg Agricultural Research Service/USDA
Geological Survey Bureau University of Nebraska
Iowa Department of Keim Hall, East Campus
Natural Resources Lincoln, NE 68583
123 N. Capitol Street
Iowa City, IA 52242
R H. Fox
Department of Agronomy
S. Jurgens-Gschwind Pennsylvania State University
BASF Aktiengesellschaft University Park, PA 16802
Agricultural Research Station
P.O. Box 220
6703 Limburgerhoff G. W. Thomas
Federal Republic of Germany Department of Agronomy
University of Kentucky
Lexington, KY 40506
W. A. Jury
Department of Soil and
Environmental Science M. S. Smith
University of California Department of Agronomy
Riverside, CA 92521 University of Kentucky
Lexinton, KY 40506
D. R. Nielson
Department of Land, Air, R. E. Phillips
and Water Resources Department of Agronomy
113 Veihmeyer Hall University of Kentucky
University of California Lexington, KY 40506
Davis, CA 95616
XV
M. P. Russelle
Agricultural Research Service/USDA
University of Minnesota
439 Borlaug Hall
1991 Upper Buford Circle
St. Paul, MN 55108
W. L. Hargrove
Department of Agronomy
University of Georgia
Experiment, GA 30212
D. F. Heerman
Agricultural Research Service/USDA
Agricultural Engineering Research Center
Colorado State University
Fort Collins, CO 80523
H. R. Duke
Agricultural Research Service/USDA
Agricultural Engineering Research Center
Colorado State University
Fort Collins, CO 80523
J. van Schilfgaarde
Agricultural Research Service/USDA
Drake Executive Plaza, Suite 350
2625 Redwing Road
Fort Collins, CO 80526
H. Bouwer
Agricultural Research Service/USDA
U.S. Water Conservation Laboratory
4331 East Broadway Road
Phoeniz, AZ 85040
R. R. Lowrance
Agricultural Research Service/USDA
Southeast Watershed Unit
P.O. Box 946
Tifton, GA 31793
H. B. Pionke
Agricultural Research Service/USDA
Northeast Watershed Research Center
Pennsylvania State University
110 Research Building A
University Park, PA 16802
1
Chapter 1
GROUND WATER QUALITY CONCERNS ABOUT NITROGEN
R. F. FOLLETT and D. J. WALKER
USDA, ARS, Soil-Plant-Nutrient Research Unit, P.O.Box E, Fort Collins, CO
80522 and Department of Agricultural Economics and Rural Sociology, University
of Idaho, Moscow, ID 83843.
ABSTRACT
Concern by the public and others exists about the health, economic, and
resource conservation aspects of nitrate leaching into ground water supplies.
An examination of these topics as they relate to nitrogen (N) management and
ground water protection is made. During the past 10 years, annual N
fertilizer consumption has increased about 25 percent in Developed Countries
and about 160 percent in Developing Countries of the World. The public is
concerned about toxicity and health effects of nitrate that may be entering
ground water supplies used for drinking water. Of special concern are
methemoglobinemia and cancer. Both are discussed as they relate to the
possible effects of nitrate ingestion and public health. The economic
importance of N for crop production is well known. However, practices to
minimize N losses are important to protection of ground water. Benefits of
decreasing nitrate pollution in ground water are diffuse, enjoyed by all users
of the aquifer, while costs of improving ground water quality are relatively
concentrated among farmers who must alter their farming practices to reduce
nitrate leaching. Therefore, some form of government intervention is needed
to allign the interests of the individual farmer with the broader social
interest. Several public policy options are discussed. Finally, the
relationship on N fertilizer use, and modern technology in general, to
resource conservation is addressed. Generally, increased crop yields allow
more erosive or poorer land to be removed from production, thus decreasing
soil erosion and production costs. The relationship of various management,
land use, and soil factors to ground water nitrate concentrations are also
discussed.
1 INTRODUCTION
Supplying crops with adequate nitrogen (N) is vital to ensuring food
supplies both nationally and internationally. Nitrogen can be added or
returned to soil for crop production through fertilizer, manure, crop residue,
rainfall, and biological fixation. Once N from any of these various sources
is added to the soil, it is subject to chemical transformations that occur in
the N cycle (Figure 1), including transformation to nitrate. Providing crops
with too little N results in decreased crop yields and poor economic returns,
while providing them too much may result in the accumulation of mineral forms
of N (ammonium and nitrate) within the crop root zone. Excessive amounts of
