Biological Nitrogen Fixation for Sustainable Agriculture: Extended versions of papers presented in the Symposium, Role of Biological Nitrogen Fixation in Sustainable Agriculture at the 13th Congress of Soil Science, Kyoto, Japan, 1990

211 Pages·1992·5.99 MB·English

by  B. B. Bohlool

BIOLOGICAL NITROGEN FIXATION FOR SUSTAINABLE AGRICULTURE
Developments in Plant and Soil Sciences
VOLUME49
The titles published in this series are listed at the end of this volume.
Biological Nitrogen Fixation
for Sustainable Agriculture
Extended versions of papers presented in the Symposium,
Role of Biological Nitrogen Fixation in Sustainable Agriculture
at the 13th Congress of Soil Science, Kyoto, Japan, 1990
Edited by
J.K.LADHA
International Rice Research Institute
Manila, Philippines
T. GEORGE and B. B. BOHLOOL
Nitrogen Fixation by Tropical
Agriculture Legumes
(NijTAL) Project
University of Hawaii,
Honolulu, Hawaii, USA
Reprinted from Plant and Soil, Volume 141 (1992)
Springer-Science+Business Media, B.V.
Library of Congress Catalog ing in Publication Data
ISBN 978-90-481-4164-7 ISBN 978-94-017-0910-1 (eBook)
DOI 10.1007/978-94-017-0910-1
AII Rights Reserved
© 1992 Springer Science+Business Media Dordrecht
Originally published by Kluwer Academic Publishers in 1992
Softcover reprint of the hardcover 1s t edition 1992
No part of the material protected by this copyright notice
may be reproduced or utilized in any form or by any means,
electronic or mechanical, including photocopying,
recording, or by any information storage and retrieval
system, without written permission from the copyright
owner.
Contents
Preface vii
Dedication xi
B. B. Bohlool, J. K. Ladha, D. P. Garrity and T. George, Biological nitrogen fixation for sustainable
agriculture: A perspective
M. B. Peoples and E. T. Craswell, Biological nitrogen fixation: Investments, expectations and actual
contributions to agriculture 13
P. A. Roger and J. K. Ladha, Biological Nz fixation in wetland rice fields: Estimation and contribution to
nitrogen balance 41
I. Watanabe and C. C. Liu, Improving nitrogen-fixing systems and integrating them into sustainable rice
farming 57
T. George, J. K. Ladha, R. J. Buresh and D. P. Garrity, Managing native and legume-fixed nitrogen in
lowland rice-based cropping systems 69
I. R. Kennedy and Y.-T. Tehan, Biological nitrogen fixation in non-leguminous field crops: Recent
advances 93
H. H. Keyser and F. Li, Potential for increasing biological nitrogen fixation in soybean 119
S. F. Ledgard and K. W. Steele, Biological nitrogen fixation in mixed legume/grass pastures 137
K. Fujita, K. G. Ofosu-Budu and S. Ogata, Biological nitrogen fixation in mixed legume-cereal cropping
systems 155
S. K. A. Danso, G. D. Bowen and N. Sanginga, Biological nitrogen fixation in trees in agro-ecosystems 177
J. Ishizuka, Trends in biological nitrogen fixation research and application 197
Plant and Soil 141, vii, 1992.
Preface
Sustainability is defined as "the successful management of resources for agriculture to satisfy changing
human needs while maintaining or enhancing the quality of the environment and conserving resources"
(Technical Advisory Committee of Consultative Group on International Agricultural Research).
Economists view sustainability as the ratio of input to output, taking into account stock depletion. In
agriculture, stocks include soil, water, nonrenewable energy resources and environmental quality.
Industrially produced N fertilizer depletes nonrenewable energy resources and poses human and
environmental hazards. In developing countries, importing N or building fertilizer plants requires scarce
foreign exchange. Atmospheric n is virtually unlimited, but it must be converted to a plant-usable form
through biological or nonbiological processes.
Biological N fixation (BNF) is a vital component of agricultural sustainability. It can be a rna jor N
source in symbiotic systems such as legumes, or a minor source supplementing inorganic N in
nonsymbiotic, nonlegumes such as cereals. Nonsymbiotic BNF is important in replenishing soil N
depleted by crop removal or lost through leaching, volatilization, and denitrification in nonfertilized or
moderately fertilized irrigated lowland rice where soil N is maintained naturally. Even heavily
N-fertilized systems marked by high cropping intensity may experience soil N depletion. In these soils
sustainability depends on symbiotic and nonsymbiotic BNF.
Tremendous progress in BNF biochemistry and genetics has been made in the last 30 years, yet we
are still hoping for breakthroughs in nif gene transfer from legumes to nonlegumes. Much more basic
work is required. In the meantime, we should ask whether basic research is being pursued at the
expense of applied research. Relevant basic research must continue, but of equal or greater importance
is applied farm-level research.
This book is a product of the symposium, Role of Biological Nitrogen Fixation in Sustainable
Agriculture, jointly organized by the International Society of Soil Science and the International Rice
Research Institute at the 13th International Congress of Soil Science, Kyoto, Japan. Papers on BNF in
major crops and cropping systems were augmented by discussions of integrated cropping systems
involving BNF, soil and N management, recycling of crop residues, and multipurpose legumes. Recent
work on promising BNF systems and their potential for exploitation were discussed. There was also a
presentation on donor perspectives on research priorities and funding. This present volume brings
together extended versions of all technical papers presented, and a perspective paper on BNF for Sustainable
Agriculture.
J.K. Ladha
Chairman of the Symposium
B. Ben Bohlool
1940-1991
Plant and Soi/141, xi, 1992.
B. Ben Bohlool
Dedication
The BNF community throughout the world was saddened by the death of Dr. B. Ben Bohlool,
University of Hawaii NifTAL Project Director, on 16 May 1991. This book is dedicated to his memory,
in honor of the many contributions he made to this field.
Ben was born in Tehran, Iran, in 1940. In 1971, he graduated with a Ph.D. in microbial ecology from
the University of Minnesota at Minneapolis under Dr. E.L. Schmidt. His doctoral work focused on the
use of immunofluorescence in the study of the ecology of Rhizobium japonicum in soils. Further
post-doctoral research with Dr. Schmidt resulted in their formulation of the lectin hypotheses. This
pioneering work suggested that lectins were a possible basis for specificity in the legume-rhizobia
symbiosis.
Ben dedicated his research career to understanding this nitrogen fixing symbiosis. In 1976, Ben joined
the faculty of the University of Hawaii. His research there encompassed several major areas including
the ecology of rhizobia in tropical soils, assessing the potential of fast-growing soybean rhizobia from
China, and studying the host regulation of the legume-rhizobia symbiosis. During his tenure at the
University of Hawaii, Ben was the recipient of the Alexander van Humboldt Fellowship, and spent six
months with the molecular genetics group at Max-Planck Institute in Cologne, Germany.
In 1985 Ben was appointed Director and Principal Investigator of the NifTAL (Nitrogen Fixation by
Tropical Agricultural Legumes) Project. As NifTA L's Director, Ben fostered his vision of the Project
as both a dynamic research institute as well as a responsive resource for promoting BNF in agricultural
development. He Jed the Project in developing international outreach and training activities, and was
nominated for the World Food Prize for these efforts. Ben also remained active in research, and
supported an international network of researchers in rhizobia! ecology to study environmental effects
on the occurrence, persistence, and performance of rhizobia in tropical soils.
Ben is remembered by his friends and colleagues as an excellent and creative scientist. He was blessed
with an insatiable curiosity, social gregariousness, and the ability to savor all aspects of life. Besides his
own scientific contributions, Ben's legacy includes the continuing work of his graduate students, and
that of his colleagues promoting BNF for sustainable agricultural development.
Plant and Soil141: 1-11, 1992
© 1992 Kluwer Academic Publishers. PLSO SA01
Biological nitrogen fixation for sustainable agriculture: A perspective
B. B. BOHLOOL\ J. K. LADHA2, D. P. GARRITY2 and T. GEORGE1
1NifTAL Project, University of Hawaii, 1000 Holomua Avenue, Paia, HI 96779, USA and
2International Rice Research Institute (IRRI), P.O. Box 933, Manila, Philippines
Key words: chemical fertilizer, crop production, developing countries, environment, inoculation,
legume, pollution
Table of contents
Abstract
Introduction
The issue of sustainability in agriculture
Economic considerations: The fossil-fuel outlook
Environmental considerations: Health and ecological impacts
Production sustainability: Management of internal resources
Constraints to utilization of nitrogen fixing systems
Environmental constraints
Biological constraints
Methodological constraints
Production-level constraints
Socio-cultural constraints
Conclusion
References
Abstract
The economic and environmental costs of the heavy use of chemical N fertilizers in agriculture are a
global concern. Sustainability considerations mandate that alternatives to N fertilizers must be urgently
sought. Biological nitrogen fixation (BNF), a microbiological process which converts atmospheric
nitrogen into a plant-usable form, offers this alternative. Nitrogen-fixing systems offer an economically
attractive and ecologically sound means of reducing external inputs and improving internal resources.
Symbiotic systems such as that of legumes and Rhizobium can be a major source of N in most cropping
systems and that of Azolla and Anabaena can be of particular value to flooded rice crop. Nitrogen
fixation by associative and free-living microorganisms can also be important. However, scientific and
socio-cultural constraints limit the utilization of BNF systems in agriculture. While several environmen
tal factors that affect BNF have been studied, uncertainties still remain on how organisms respond to a
given situation. In the case of legumes, ecological models that predict the likelihood and the magnitude
of response to rhizobia! inoculation are now becoming available. Molecular biology has made it possible
to introduce choice attributes into nitrogen-fixing organisms but limited knowledge on how they interact
with the environment makes it difficult to tailor organisms to order. The difficulty in detecting
introduced organisms in the field is still a major obstacle to assessing the success or failure of
2 Bohlool et al.
inoculation. Production-level problems and socio-cultural factors also limit the integration of BNF
systems into actual farming situations. Maximum benefit can be realized only through analysis and
resolution of major constraints to BNF performance in the field and adoption and use of the technology
by farmers.
Introduction into account stock depletion. Stocks in agricul
ture include soil, water, nonrenewable energy
Chemical fertilizers have had a substantial im resources, and environmental quality.
pact on food production in the recent past, and Modern agriculture is based on maximum out
are today an indispensable part of modern ag put in the short term, with inadequate concern
ricultural practices. The Green Revolution of the for input efficiency or stock maintenance
past half-century was fueled by technologies (Odum, 1989). Nitrogen fertilizer ranks first
heavily dependent on synthetic fertilizers. Rus among the external inputs to maximize output in
sell et al. (1989) estimate that in 1985, the use of agriculture. Input efficiency of N fertilizer is one
38.8 million Mt of N fertilizer on cereals globally of the lowest among the plant nutrients and, in
resulted in increased world cereal production of turn, contributes substantially to environmental
938 million Mt, more than half of the total cereal pollution. The continued and unabated use of N
production in that year. They defined a relation fertilizers would further accelerate depletion of
ship between world N fertilizer use on cereals stocks of non-renewable energy resources used
(X) and mean world cereal yield (Y), between in fertilizer production. The removal of large
1956 and 1985, which could be expressed by the quantities of crop produce from the land addi
equation Y = 1202 + 13.3X, with R2 = 0.983 em tionally depletes soil of its native N reserves. On
phasizing the major driving force of N fertilizers the other hand, BNF, a microbiological process
in food production today. in the biosphere, converts atmospheric dinitro
There are, on the other hand, vast areas of the gen into a plant-usable form through the micro
developing world where N fertilizers are neither bial enzyme nitrogenase. Nitrogen input through
available nor affordable. Furthermore, in most BNF can help maintain soil N reserves as well as
of these countries, removal of N fertilizer sub substitute for N fertilizer to attain large crop
sidies, due to balance of payment problems, yields (Peoples and Craswell, 1992).
have resulted in higher prices and lower supplies. Another issue which needs urgent attention is
Even in wealthier nations, economic and en the decline in crop yields under continuous use
vironmental considerations dictate that biological of N fertilizers. The trend of the 1970s of in
alternatives which can augment, and in some creasing crop yields from fertilizer N addition
cases replace, N fertilizers must be sought. The has recently been slowed down both in the de
process of biological nitrogen fixation (BNF) veloped (Plucknett and Smith, 1986) and in the
offers this alternative. In this paper, we outline developing countries (Barker and Chapman,
sustainability issues that dictate increased use of 1988; Byrlee, 1987). Odum (1989) indicated that
BNF and the constraints to optimal use of BNF a 4-fold increase in crop yield during the 1970s
in agriculture. and 80s occurred at an 11-fold increase in fertil
izer N use in Georgia, USA. An analysis of
several years' data on rice yields from ex
The issue of sustainability in agriculture perimental stations in Philippines, Indonesia and
Thailand by Pingali et al. (1990) shows trends of
Sustainability is defined as 'the successful man stagnation or decline.
agement of resources to satisfy changing human
needs while maintaining or enhancing the quality Economic considerations: The fossil-fuel
of the environment and conserving resources' outlook
(TAC, CGIAR, 1978). Economists measure sus
tainability as the ratio of output to input, taking The oil crisis of the 1970s and the current Middle