Table Of ContentProceedings of Previous Easter Schools in Agricultural Science, published by Butterworths, London
*SOIL ZOOLOGY Edited by D. K. McL. Kevan (1955)
THE GROWTH OF LEAVES Edited by F. L. Milthorpe (1956)
"CONTROL OF PLANT ENVIRONMENT Edited by J. P. Hudson (1957)
"NUTRITION OF THE LEGUMES Edited by E. G. Hallsworth (1958)
THE MEASUREMENT OF GRASSLAND PRODUCTIVITY Edited by J. D. Ivins (1959)
"DIGESTIVE PHYSIOLOGY AND NUTRITION OF THE RUMINANT Edited by D. Lewis (1960)
"NUTRITION OF PIGS AND POULTRY Edited by J. T. Morgan and D. Lewis (1961)
"ANTIBIOTICS IN AGRICULTURE Edited by M. Woodbine (1962)
"THE GROWTH OF THE POTATO Edited by J. D. Ivins and F. L. Milthorpe (1963)
"EXPERIMENTAL PEDOLOGY Edited by E. G. Hallsworth and D. V. Crawford (1964)
"THE GROWTH OF CEREALS AND GRASSES Edited by F. L. Milthorpe and J. D. Ivins (1965)
"REPRODUCTION IN THE FEMALE ANIMAL Edited by G. E. Lamming and E. C. Amoroso (1967)
"GROWTH AND DEVELOPMENT OF MAMMALS Edited by G. A. Lodge and G. E. Lamming (1968)
"ROOT GROWTH Edited by W. J. Whittington (1968)
"PROTEINS AS HUMAN FOOD Edited by R. A. Lawrie (1970)
"LACTATION Edited by I. R. Falconer (1971)
"PIG PRODUCTION Edited by D. J. A. Cole (1972)
"SEED ECOLOGY Edited by W. Heydecker (1973)
HEAT LOSS FROM ANIMALS AND MAN: ASSESSMENT AND CONTROL Edited by J. L. Monteith and
L. E. Mount (1974)
"MEAT Edited by D. J. A. Cole and R. A. Lawrie (1975)
"PRINCIPLES OF CATTLE PRODUCTION Edited by Henry Swan and W. H. Broster (1976)
"LIGHT AND PLANT DEVELOPMENT Edited by H. Smith (1976)
"PLANT PROTEINS Edited by G. Norton (1977)
"ANTIBIOTICS AND ANTIBIOSIS IN AGRICULTURE Edited by M. Woodbine (1977)
"CONTROL OF OVULATION Edited by D. B. Crighton, N. B. Haynes, G. R. Foxcroft and G. E. Lamming
(1978)
"POLYSACCHARIDES IN FOOD Edited by J. M. V. Blanshard and J. R. Mitchell (1979)
"SEED PRODUCTION Edited by P. D. Hebblethwaite (1980)
PROTEIN DEPOSITION IN ANIMALS Edited by P. J. Buttery and D. B. Lindsay (1980)
PHYSIOLOGICAL PROCESSES LIMITING PLANT PRODUCTIVITY Edited by C. Johnson (1981)
ENVIRONMENTAL ASPECTS OF HOUSING FOR ANIMAL PRODUCTION Edited by J. A. Clark (1981)
"EFFECTS OF GASEOUS AIR POLLUTION IN AGRICULTURE AND HORTICULTURE
Edited by M. H. Unsworth and D. P. Ormrod (1982)
CHEMICAL MANIPULATION OF CROP GROWTH AND DEVELOPMENT Edited by J. S. McLaren (1982)
CONTROL OF PIG REPRODUCTION Edited by D. J. A. Cole and G. R. Foxcroft (1982)
SHEEP PRODUCTION Edited by W. Haresign (1983)
"UPGRADING WASTE FOR FEEDS AND FOOD Edited by D. A. Ledward, A. J. Taylor and R. A. Lawrie
(1983)
FATS IN ANIMAL NUTRITION Edited by J. Wiseman (1984)
IMMUNOLOGICAL ASPECTS OF REPRODUCTION IN MAMMALS Edited by D. B. Crighton (1984)
ETHYLENE AND PLANT DEVELOPMENT Edited by J. A. Roberts and G. A. Tucker (1985)
THE PEA CROP Edited by P. D. Hebblethwaite, M. C. Heath and T. C. K. Dawkins (1985)
"PLANT TISSUE CULTURE AND ITS AGRICULTURAL APPLICATIONS Edited by Lindsey A. Withers and
P. G. Alderson (1986)
CONTROL AND MANIPULATION OF ANIMAL GROWTH Edited by P. J. Buttery, N. B. Haynes and
D.B.Lindsay (1986)
COMPUTER APPLICATIONS IN AGRICULTURAL ENVIRONMENTS Edited by J. A. Clark, K. Gregson
and R. A. Saffell (1986)
MANIPULATION OF FLOWERING Edited by J. G. Atherton (1987)
FOOD STRUCTURE - ITS CREATION AND EVALUATION Edited by J. R. Mitchell and J. M. V. Blanshard
(1988)
NUTRITION AND LACTATION IN THE DAIRY COW Edited by P. C. Garnsworthy (1988)
MANIPULATION OF FRUITING Edited by C. J. Wright (1989)
FEEDSTUFF EVALUATION Edited by J. Wiseman and D. J. A. Cole (1990)
GENETIC ENGINEERING OF CROP PLANTS Edited by G. W. Lycett and D. Grierson (1990)
* These titles are now out of print but are available in microfiche editions
Applications of Remote Sensing in
Agriculture
M. D. STEVEN
Lecturer in Geography, University of Nottingham
J. A. CLARK
Senior Lecturer in Environmental Science, University of Nottingham School of
Agriculture
BUTTERWORTHS
London Boston Singapore Sydney Toronto Wellington
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First published 1990
© Contributors 1990
British Library Cataloguing in Publication Data
Clark, J. A. (Jeremy Austin), 1938-
Applications of remote sensing in agriculture.
1. Great Britain. Agriculture
I. Title II. Steven, M.D.
338.16
ISBN 0-408-04767-4
Library of Congress Cataloging-in-Publication Data
Applications of remote sensing in agriculture/[edited by] J. A.
Clark, M.D. Steven
p. cm.
Includes bibliographical references
ISBN 0-408-04767-4:
1. Agriculture-Remote sensing. I. Clark, J.A. (Jeremy Austin),
1939- . II. Steven, M.D.
S494.5.R4A66 1990
630'.28-dc20 90-1778
Composition by Genesis Typesetting, Laser Quay, Rochester, Kent
Printed in Great Britain at the University Press, Cambridge
PREFACE
This book represents the proceedings of the 48th Easter School in Agricultural Science
held at the University of Nottingham from 3rd -7th April 1989. The meeting attracted
146 delegates from over 22 countries and contributions to this volume come from 9
countries. The editors have divided the contributions on thematic lines according to the
agricultural problems addressed, but within each theme a variety of technical approaches
are described by different authors. The volume as a whole presents a review of the
achievements of remote sensing in agriculture, establishes the state of the art and gives
pointers to future developments.
At an international gathering of this nature there is naturally a diversity of ap
proach, but there appears a surprising unity of purpose reflected in the recurrent theme
of estimating the production and predicting the yields of crops. Indeed, this concern has
an ancient history, for in the book of Genesis, chapter 41, we find the story of Joseph
(he of the coat of many colours) interpreting the dreams of the Pharaoh to predict seven
years of plenty followed by seven years of famine. The story serves as a reminder that the
real needs of agricultural and economic planning are for long-term forecasts: Few would
rely on remote sensing techniques to predict yields as far as 14 years ahead, despite the
considerable scientific progress reported in this volume!
The characteristic spectral signature of vegetation in the visible and near-infrared
bands was recognised early in the history of remote sensing and applications of remote
sensing in agriculture were envisaged in the original specifications of Landsat. It is per
haps surprising, then, that satellite remote sensing techniques have found few "real-
world" applications in agriculture, despite some early successes such as the LACIE pro
gramme. A large part of the difficulty in application has been due to logistics. Satellite
systems that have the resolution to recognize individual fields are constrained to repeat
cycles that are too long to characterize the growing season of a typical annual crop,
especially when loss of data under cloud cover is considered.
A number of approaches to resolve this problem are reported in this volume. The
French SPOT satellite can direct its sensors towards specified targets that are off the
immediate sub-satellite track. This system can thus monitor a specified area on sev
eral occasions within its 26-day repeat cycle, but with the constraint that selection of
v
VI Preface
a particular target for frequent monitoring is made at the expense of neighbouring po
tential targets. A second approach uses low-resolution satellite data to monitor regional
phenological change or associated meteorological factors. A third approach is to use mi
crowaves, either passively, using natural emissions, or actively, with radar. Microwaves
are unaffected by cloud cover but their interactions with vegetation and soil are complex
and the match between the information content of microwaves and the requirements of
agricultural users is as yet unclear. A fourth approach is to liberate the remote sensing
techniques from the constraints of a satellite platform. Aerial photography is still the
best option for investigation of many agricultural problems at scales smaller than the
field. And, in the future, 'ultra-low altitude' platforms such as tractors may allow the
use of the full range of monitoring techniques to solve the down-to-earth problems of
farmers, rather than those of governments or commodity brokers.
M.D. Steven
J.A. Clark
ACKNOWLEDGEMENTS
We would like to extend our thanks to the many people who helped to make the con
ference a success: To Tim Malthus and Mark Danson who provided invaluable help in
the organization and administration of the meeting; To Brenda Champion and Patricia
Steven who ran the registration desk and sorted out many of the "real-world" problems
of participants; and to John Corrie who managed the visual aids. We also thank the
team at Butterworths, particularly Patricia Horwood and Sharon Cooper, for their help
in producing this volume, and John Burgess, who tackled the typesetting 'in-house', over
coming his own limited experience, and the complexities of the text program provided
on the University Computer.
The Editors and the University of Nottingham School of Agriculture are grateful to
the following organizations for their generous financial assistance towards the expenses
of the School:
U.K. Overseas Development Administration,
Campbell Scientific Ltd.,
The Royal Society,
Eurimage,
Logica Space and Defence Systems Ltd.,
The Remote Sensing Society.
vii
1
SENSORS, PLATFORMS AND APPLICATIONS;
ACQUIRING AND MANAGING REMOTELY SENSED
DATA
J.A. ALLAN
School of Oriental and African Studies,
University of London, Russell Square, London WC1H OXG, U.K.
Introduction
Current and future sensors will be discussed in terms of the evolution of the suite of
technologies which contribute to remote sensing and of the requirements of agricultural
applications. The initial treatment will be historical, in order to provide a perspective
on the significant and enduring place of some platforms and sensors, such as the aircraft
and the camera. The main emphasis will be given to the experience gained in the past
two decades with multi-spectral scanners and the 'push-broom' devices deployed from
space in the civil domain since the early 1980s. The limited operational use of microwave
sensing in agricultural applications will be commented upon.
Future platforms and sensors will be discussed in terms of the alternative strate
gies of synergism and free flying platforms. The commitment of the USA and ESA to
Space Station and the Columbus Project indicate an emphasis on the monitoring of the
Earth's surface at a small scale for global science, an explicit goal of NASA. Agricultural
applications will be served by the 1990's NASA and ESA programmes, but it is argued
that it is likely to be other free-flying systems which provide the operational data for
agricultural monitoring and management in future.
Some general features of agricultural applications
Agricultural applications have many features in common with other land applications,
for example the relevance of the large area covering capacity and the great usefulness of
multi-date and multi-spectral data. But agricultural applications differ from the other
major land application areas in a number of ways. Agricultural applications are charac
terized by a number of phenological, land management and economic features, which to
gether ensure that remote sensing has and will continue to play an increasingly significant
role in monitoring agricultural tracts, especially at the national level. The community
interested in the remote sensing of agricultural areas is large and diverse, and includes
scientists, members of national and international government institutions (eg the EEC,
3
4 Sensors, Platforms and Applications
ESA, ASEAN etc), national agencies (eg, USAID, ODA), international agencies (FAO,
World Bank, IFAD) as well as consulting organisations and many large and small public
companies concerned with resource and environmental management.
Agricultural applications also differ from many major application groupings in that
there is often an especially large body of complementary, and often alternative, data
with which remotely sensed data have to be integrated or for which they substitute.
Often the complementarity between the various data sources is obvious, but on occasions
the remotely sensed data appear to compete with land surface data otherwise derived.
Without any attempt to prepare a comprehensive list of agricultural applications, it
has been easy to list ten major scientific applications and over thirty renewable and
non-renewable resource survey and management applications, ranging from land surface
climate monitoring to studies of wild-life. While the main role of agricultural applications
is, and will continue to be, at the national level, there will be an increasing role for them
at the international level (Table 1.1).
Although the list of current and potential applications is long and the outcomes sig
nificant, not all the potential users of data recorded by remote sensing systems assimilate
such information into operational systems with equal facility. The scientific community
in the fields of land evaluation and agro-ecological studies is usually only deterred from
using such data by their cost. The management community is often also inhibited by
cost, but in many cases it is the unfamiliarity of the data which prevents their deploy
ment. Professionals using existing systems are often unwilling to see the advantages of
new systems, fearing that existing jobs might be replaced by the comprehensive coverage
of satellite observation.
Trends in technological development
Earth observation from airborne platforms has a one hundred and thirty year history,
although the majority of the innovation and development has taken place in the last
twenty years. The developments of the next two decades are likely to be characterized by
rates of growth similar to those of the recent past, despite the problems of funding space
platforms and observing systems. While changes have been rapid there are a number of
enduring features of Earth observing technologies.
Amongst platforms the aircraft is the most important example, although by now
the volume of observation from satellites has massively overtaken air-photo archival ma
terials in terms of coverage if not of scale. The number of platforms in orbit is large and
increasing. The Soviet Union has launched more than four times as many missions as
the United States, but many of these were of short duration for surveillance purposes.
Other nations have the capacity to construct and launch platforms, including France,
Japan, and China. Launch services are being provided by the two major participants in
the development of space as well as by France and China. A useful survey of the civil
and military programmes is available (Warwick, 1985), see Table 1.2.
Of sensors, the camera has a classic place but, though present on many space projects
as a large format camera, it has been mainly replaced for routine observation by other
sensors: the multi-spectral scanners; charge-coupled linear and array devices (CCDs);
thermal sensors; microwave sounders and scanners; spectrometers and lidars. Global
positioning systems are also becoming commonplace, greatly enhancing the geometric
potential of all observing systems. The most important development in sensors will be
Allan, J.A. 5
TABLE 1.1. Agricultural applications of remote sensing.
Scientific applications of relevance in agriculture
Crop science Hydrology
including all types of Surface run-off
vegetation indices Groundwater
Stress detection Land surface climatology
Agro-climatology Soil science
Agro-ecology Terrestrial ecosystems
'Global change' Vegetation science,
including forest science
Management applications of remote sensing in agriculture
Agriculture Land evaluation
Agro-ecology Land use
Crop damage Land degradation
Crop condition Soil erosion
Crop inventory - local, regional, Soil salinity
national and global Land drainage
Crop classification Land classification
Livestock inventory Land reclamation
Yield estimation Agricultural
Yield prediction Urban
Degraded land studies Pollution
Environmental impact studies of soil
- of agricultural development of vegetation
- of urban development Rangeland management
GIS - contributions to regional Rangeland condition
agricultural information systems Rangeland classification
Irrigated lands Range production
Inventory Soil survey
Monitoring extent
Crop condition
Water utilisation
Regulation of water use
6 Sensors, Platforms and Applications
TABLE 1.2. The technological history of land applications. The data provided by such technolo
gies had relatively little impact on agriculture until the 1930s when air photographs began to
be used for soil survey, for example in the advisory services of the USDA. Both before and since
the input of remotely sensed data into topographic mapping was of some importance in farm
planning and in rural engineering activities connected with soil conservation, land drainage and
irrigation.
Platforms Sensors Data User
storage technology
and software
1860 Balloon Camera Photograph Cartographic
Eye/brain techniques
and the eye/brain
1960 Aircraft Camera, Photograph Cartographic
techniques
Satellites LFC and MS Digital and the eye/brain
MSS scanners tape/disc Automated digital
for most of cartography (ADC)
e.m. spectrum Computer
Radiometers
1985 Aircraft Camera, Photograph Cartographic
techniques
Satellites LFC and MS Digital and the eye/brain
Super MSS and tape/disc ADC, GIS
CCD devices Optical Microcomputer
Microwave networked
sensors and Super-computer
altimeters
Spectrometers
Lidars
GPS
NB. The eye/brain is still useful
2000 Aircraft Camera - LFC Photograph Cartographic
Satellites ATSR, SAR, Digital Techniques and
Space HIRIS, HMMR, tape/disc the eye/brain
stations MODIS type ADC, GIS
instruments A computer
GPS beyond
superlatives
