Toward Agroforestry Design

162 Pages·2008·14.18 MB·English

Shibu Jose Andrew M. Gordon
Advances in Agroforestry
Editors
Volume 4
Series Editor:
P.K.R. Nair
School of Forest Resources and Conservation, Toward Agroforestry Design
University of Florida, Gainesville, Florida, U.S.A.
Aims and Scope
An Ecological Approach
Agroforestry, the purposeful growing of trees and crops in interacting combinations, began to attain
prominence in the late 1970s, when the international scientific community embraced its potentials
in the tropics and recognized it as a practice in search of science. During the 1990s, the relevance
of agroforestry for solving problelns related to deterioration of family farms, increased soil erosion,
surface and ground water pollution, and decreased biodiversity was recognized in the industrialized
nations too. Thus, agroforestry is now receiving increasing attention as a sustainable land-management
option the world over because of its ecological, economic, and social attributes. Consequently, the
knowledge-base of agroforestry is being expanded at a rapid rate as illustrated by the increasing
number and quality of scientific publications of various forms on different aspects of agroforestry.
Making full and efficient use of this upsurge in scientific agroforestry is both a challenge and an
opportunity to the agroforestry scientific community. In order to help prepare themselves better for
facing the challenge and seizing the opportunity, agoroforestry scientists need access to synthesized
information on multi-dimensional aspects of scientific agroforesty.
The aim of this new book-series, Acivlvance.~i rz [email protected], is to offer state-of-the art synthesis of
research results and evaluations relating to different aspects of agroforestry. Its scope is broad enough
to encompass any and ail aspects of agroforestry research and development. Contributions are welcome
as well as solicited from competent authors on any aspect of agroforestry. Volumes in the series will
consist of reference books, subject-specific monographs, peer-reviewed publications out of conferences,
comprehensive evaluations of specific projects, arid other book-length compiiatio~~ofs scientific and
professional merit 'and relevance to the science and practice of agroforestry worldwide.
a
-
Springer
The titles puldished iit this series are listed at end of rlzis volurtze.
Andrew M. Gordon Preface
Shibu Jose
University of Guelph
University of Florida
Gainesville, FL ON, Canada
USA
Ecology and its underlying principles have not received much attention in the
agroforestry research and development arena despite its pivotal role in determining
the biological sustainability of agroforestry systems. Although often acknowledged,
ecological principles are seldom explored in many of the world's best developed
and well-known agroforestry systems. However, it is worth noting that this trend is
slowly changing as we recognize that agroforestry systems, if not designed based
on sound ecological principles, are unable to attain their fullest potential. In fact,
the last 5 years have seen an exponential increase in journal articles and synthesis
work that explore the ecological foundations of global agroforestry practices.
The idea for the current book originated following the 1st World Congress of
Agroforestry, Orlando, FL, USA, June-July, 2004. We, the editors of this book,
llad organized two sessions, both focused on the ecological basis for designing
agroforestry systems. Invited and voluntary papers and posters were presented in
these sessions which represented a cross-section of the current global biophysical
research being conducted in a variety of agroforestry systems. Dr. P.K.R. Nair,
the Chair of the Organizing Committee of the 1st World Congress of Agroforestry,
encouraged us to consider publishing an edited volume in the new book series,
Advances in Agroforestry, for which he serves as the series editor. We accepted his
advice enthusiastically and immediately started working on the project. Selected
authors were invited to submit manuscripts for peer review; we subsequently
went through a rigoro~isp eer review process that resulted in the acceptance of
ISBN 978- 1-4020-657 1-2 e-ISBN 978- 1-4020-6572-9
14 manuscripts for the current volume.
Library of Congress Control Number: 2007936553 The manuscripts represent a mix of original research and synthesis work
from both tropical and temperate regions of the world. We have grouped them
O 2008 Springer Science + Business Media B.V.
into five sections. The first section that consists of one chapter is an introduction
No part of this work may be reproduced, stored in a retrieval system, or transrnitted in any form or
by any means, electronic, mechanical, photocopying, rnicrofilm~ng,r ecording or otherwise, without to the role of ecological knowledge in agroforestry design. The second section
written permission fro111 the Publisher, with the exceptioll of any material supplied specifically for has eight chapters that explore the resource allocation patterns and aboveground
the nurpose of being entered and executed on a computer system, for exclusive use by the purchaser
processes in various agroforestry systems. The four chapters included in the third
of tile work.
section deal with resource allocation patterns with respect to belowground processes,
Printed on acid-free paper. while recent advances in analytical and modeling tools are explored in the fourth
section. The final section is a chapter that synthesizes the current state of
knowledge with respect to ecological knowledge in agroforestry systems.
vi Preface
We are grateful to a large number of individuals for their assistance in
accomplishing this task. We would like to express our sincere gratitude to
Dr. P.K.R. Nair for his continued support and encouragement throughout
the publication process. In addition, we thank the authors for their long and
continued commitment to this project. The invaluable comments and sugges-
tions made by the referees also significantly improved the clarity and content
of the chapters. In addition to many of the authors who served as reviewers
for other chapters, we thank: Samuel Allen, Kent Apostol, Michael Bannister,
Tamara Benjamin, David Burner, Barry Brecke, James Burger, Wendell Cropper,
Stanley Gathumbi, Rico Gazel, Michael Gold, James Jones, Ole Hendrickson,
Robert Kalmbacher, Andy Kenney, John Kort, Peter Nkedi-Kizza, Kye-Han
Lee, Ofelia Plascencia, James Quashie-Sam, Meka Rao, Phil Reynolds, Michelle ........................................................
Preface v
Schoeneberger, Johannes Scholberg, Richard Schultz, Dennis Shannon, Jamie
Simpson, Daniel Stephenson, Naresh Thevathasan, and Vie Timmer for their
Section 1 Introduction
help in reviewing n~anuscripts.W e also wish to extend our sincere thanks to
Catherine Cotton and her staff at Springer Science for their timely efforts in
Chapter 1 Ecological Knowledge and Agroforestry Design:
publishing this book. .....................................
AnIntroduction 3
Shibu Jose S. Jose and A.M. Gordon
June, 2007
Andrew M. Gordon
Section 2 Resource Allocation in Agroforestry Systems:
Aboveground Processes
Chapter 2 Biophysical Changes Resulting from 16 Years
of Riparian Forest Rehabilitation: An Example
......
from the Southern Ontario Agricultural Landscape.
13
Maren Oelbermann, Andrew M. Gordon, and Narinder K. Kaushik
Chapter 3 Ecological Development and Function of Shelterbelts
.........................
in Temperate North America.
27
C.W. Mize, J.R. Brandle, M.M. Schoeneberger,
and G. Bentrup
Chapter 4 Forage Production Under and Adjacent
to Robinia pseudoacacia in Central Appalachia,
......................................
West Virginia. 55
C.M. Feldhake, D.P. Belesky, and E.L. Mathias
Chapter 5 Light Intensity Effects on Growth and Nutrient-use
.............
Efficiency of Tropical Legume Cover Crops
67
V.C. Baligar, N.K. Fageria, A. Paiva, A. Silveira,
J.O. de Souza Jr., E. Lucena, J.C. Faria, R. Cabral,
A.W.V. Pornella, and J. Jorda Jr.
vii
viii Contents Contents ix
Chapter 6 Interspecific Competition in a Pecan-cotton Chapter 13 Tree Foliage Polyphenols and Nitrogen Use
Alley-cropping System in the Southern United States: in Crop-Livestock Systems of Southern Africa:
........................ ....................
IS Light the Limiting Factor?. 81 Strategies for Increasing Efficiency 207
D.S. Zamora, S. Jose, P.K.R. Nair, J.W. Jones, B.J. Brecke, P.L. Mafongoya and L. Hove
and C.L. Ramsey
Section 4 Towards Better Understanding: Analytical
Chapter 7 Modification of Microclimate and Associated and Modeling Tools for Agroforestry Research
Food Crop Productivity in an Alley-cropping
...........................
System in Northern Sudan 97 Chapter 14 The Role of Ecosystem-level Models in the Design
H. Shapo and H. Adam of Agroforestry Systems for Future Environmental
.........................
Conditions and Social Needs. 231
Chapter 8 Tree-Crop Interactions in Fruit Tree-based J.P. Kimmins, C. Welham, F. Cao,
Agroforestry Systems in the Western P. Wangpakapattanawong, and L. Christanty
Highlands of Guatemala: Component Yields
............................
and System Performance 111 Chapter 15 Radiation Availability in Agroforestry System
..........................
J.G. Bellow, P.K.R. Nair, and T.A. Martin of Coffee and Rubber Trees 249
C.A. Righi, A.M.P. Lunz, M.S. Bernardes, C.R. Pereira,
Chapter 9 Biophysical Interactions Between Timber Trees D. Dourado-Neto, and J.L. Favarin
and Arabica Coffee in Suboptimal Conditions
.................................
of Central America 133 Chapter 16 Modeling Green Manure Additions in Alley-Cropping
P. Vaast, R. van Kanten, P. Siles, J. Angrand, Systems: Linking Soil Community Dynamics
.........................
and A. Aguilar and Nitrogen Mineralization 267
Y. Carrillo and C. Jordan
Section 3 Resource Allocation in Agroforestry Systems:
Belowground Processes Chapter 17 Separating the Tree-Soil-Crop Interactions
in Agroforestry Parkland Systems in SaponC
....................
Chapter 10 Agroforestry Management Effects on Plant (Burkina Faso) using WaNuLCAS. 285
Productivity Vectors within J. Bayala, M. van Noordwijk, B. Lusiana, K. Ni'matul,
a Humid-Temperate Hardwood Z. Teklehaimanot, and S.J. Ouedraogo
..............................
Alley-Cropping System 149
G.R. von Kiparski and A.R. Gillespie Section 5 Synthesis
Chapter 11 Root Competition for Phosphorus Between Chapter 18 Applying Ecological Knowledge to Agroforestry
...............................
Coconut Palms and Interplanted Dicot Trees Design: A Synthesis.. 301
.........
Along a Soil Fertility Gradient in Kerala, India. 175 A.M. Gordon and S. Jose
H.B.S. Gowda and B.M. Kumar
.........................................................
Index 307
Chapter 12 Establishment of Cordia dodecandra A.DC.
with Bixa orellana L. on Calcareous Soils
.................................
in YucatBn, Mexico 195
M. Reuter, H. Tiessen, J.J. Jimenez-Osomio, J. Pohlan,
and P.L.G. Vlek
Section 1
Introduction
Chapter 1
Ecological Knowledge and Agroforestry
Design: An Introduction
S. Jose1,* and A.M. Gordon"
Introduction
Agroforestry is receiving long overdue attention as an alternative land-use practice
that is resource efficient and environmentally friendly. Multiple outputs and the
flexibility of having several options for management make agroforestry an attrac-
tive alternative to conventional agriculture and forestry for landowners in many
parts of both temperate and tropical regions of the world.
Although design of these integrated tree-crop and/or tree-croplivestock systems
can be flexible in order to meet the different objectives or constraints of farmers or
landowners, there are many obstacles, in both ecological and economic terms, to
overcome to make them attractive to landowners. The acceptability of agroforestry
systems by landowners would be improved if interactions that exist between trees,
crops, andor livestock remain largely beneficial so that productivity per unit area of
land is increased while reducing environmental risks associated with monocultural
systems. However, this is not an easy task. These multistoried, inulticomponent systems
are more complex than single-species cropping systems, and exhibit great variety
in temporal and spatial ecological interactions; in fact, a number of positive and
negative interactions have been postulated between different components of these
systems. In a biological context, the success of such a complex system will depend
on minimizing the negative interactions associated with forcing crops (animals or
plants) and trees to grow together spatially while enhancing the synergistic interactions
between system components.
'
School of Forest Resources and Conservation, 351 Newins-Ziegler Hail, PO Box 110410,
University of Florida, Gainesville, FL 3261 1, USA
'Dept. of Environlnental Biology, University of Guelph, Guelph, Ontario, Canada, NIG 2W1
"Corresponding author: Tel: [phone]; Fax: [phone]; E-mail: sjose8ufl.edu
S. Jose and A.M. Gordon (eds.), To~vnrcAi groforestry Design: An Ecologicul Approaclz. 3
O Springer 2008
1 Ecological Knowledge and Agroforestry Design 5
S. Jose and A.M. Gordon
Agroforestry Design / be taken into account in designing agroforestsy systems. For example, both Jose
et al. (2000) and Allen et al. (2004) observed a temporal separation in nitrogen
uptake of the tree and crop components of temperate alley-cropping systems,
It is well known that the practice of mixing of trees, crops, and livestock has been
alleviating direct competition for nitrogen between system components.
in existence for millennia. The impetus for agroforestry practices lies in the harmo-
2. Disturbance is a primary determinant of ecosystem structure and function:
nious existence of many species in natural forested ecosystems that yielded multiple
Ecosystems constantly change in ways that are only partially predictable. As
products, and in the need for historical societies with rising populations to grow tree
described by Vogl (1983) "when a living thing, community or system ceases to
and food products on a limited land base. Modern agroforestry concepts and para-
change, it is nonfunctioning, decadent, or dead". Natural systems are dynamic
digms evolved with the complex natural mixtures in mind, although Inany of the
systems, forever changing in response to successional forces, long-term fluctua-
agroforestry systems that are seen today throughout the world have only a few
tions in climate, and the more immediate effects of natural disturbance from
component species. Yet, the design and management of these systems remain chal-
disease, drought, fire, insects, stonns, and the movements of earth, wind, and
lenging because of a lack of understanding of the nature of interactions among
water. Integrating the principles of disturbance ecology into sustainable agro-
components that ultimately drive system productivity and sustainability.
forestry management practices has received considerable attention in the recent
Depending upon the type of practice, agroforestry design can involve working
past. For example, the use of fire in silvopastoral systems to stimulate forage
with a number of components. However, four key criteria characterize and distin-
productivity or thinning the tree component in order to regulate shading patterns
guish agroforestry practices from others as given below (Gold et al., 2000):
in alley cropping or multistrata systems have become routine management practices
1. Intentional: combinations of trees, crops and/or livestock are intentionally in many pasts of the world.
designed, established, andor managed to work together and yield multiple products 3. Perenninlism is the most common condition in natuml ecosystems: Natural
and benefits. systems feature perennials in mixtures rather than annuals in monoculture.
2. Intensive: agoforestry systetns are created and intensively managed to maintain Annual plants tend to dominate early in the successional process, but are quickly
their productive and protective functions and interactions and often involve cultural replaced by perennials. However, repeated disturbance events often provide
operations such as cultivation, fertilization, inigation, pruning, and thinning. periodic windows of opportunity for annuals and hence perennials and annuals
3. Integrated: components are structurally and functionally combined into a single can coexist at various stages throughout the successional progression of an
integrated management unit so that the productive capacity of the land is fully ecosystem. Agroforestry systems provide many opportunities to introduce
utilized. perennials to annual cropping systems or annuals to perennial systems depending
4. Interactive: agroforestsy systems actively manipulate and utilize the biophysical upon the objective of the landowner.
interactions among component species for optimal yield of multiple products or 4. Str~ictumla nd&nctional diversity are importclnt to ecosystem pe$ormance, but
ecosystem services. are dificult to quantify: When ecosystems consist of species that create structural
and functional diversity, resource use efficiency and system productivity are often
enhanced. The competitive exclusion principle (Gause's principle) has been
central to explaining the coexistence of species in mixtures for decades (Grime,
Ecological Approach
1973). It states that different species having identical ecological niches cannot
exist for long in the same habitat. In other words, stable coexistence of two species
The underlying principles of agroforestsy systems can be traced back to the more is only possible where intraspecific competition is greater than interspecific
complex natural systems from which they evolved. Olson et al. (2000) outlined four competition for both species. In agroforestry systems, structural and functional
general ecological principles that are comrnon to cornplex natural systems, but of diversity are increased by mixing the component species. As a result they are able
particular interest in designing agroforestry systems. They are: to coexist and increase the overall resource use efficiency of the system.
1. Ecosystems are distinguished by spatial and tempom1 heterogeneity: An ecosystem As one reads through the chapters of this book, it becomes quickly apparent that we
or landscape consist of a mosaic of patches and linear components. The boundaries or have come a long way in improving our understanding of the ecological intricacies
edges between patches or the interface of different habitat are often the sites of that define the sustainability and productivity of agroforestry systems the world over
increased rates of processes such as nutrient and energy exchange, competition, Although we may agree or disagree on how we define agroforestry in a temperate
facilitation, and movement of organisms. In agroforestry system design, the versus tropical context, researchers and practitioners agree that a better understanding
interface between the woody and non-woody components deserves special atten- of the ecology of agroforestry systems has helped in designing better systems that
tion. Optimizing the positive interactions at the interface is critical in ensuring are resource efficient and sustainable. As pointed out by van Noorwijk et al. (2004),
the sustainability of the system. Temporal variability such as phenology can also the initial enthusiasm in agroforestsy in the early 1970s resulted in a number of "any
6 S. Jose and A.M. Gordon 1 Ecological Knowledge and Agroforestry Design 7
tree plus any crop" combinations under the umbrella of "agroforestry"; however, many 3. Develop decision-s~cpportt ools and models: Formal guidelines, decision-support
of these mixtures were not yielding the expected benefits normally associated with tools and process-oriented predictive models can help advance the use of ecological
agroforestsy. This led to an increased number of scientific investigations that information in a meaningful way in terms of designing and managing new and
explored the underlying ecological priniiples of agroforestsy practices. The study existing agroforestry systems. Models help us in understanding the relationships
of ecological interactions, both above- and belowground, became the focal point of among soil, plants, trees, and other components in agroforestry systerns, particu-
the agroforestry scientific community. It started with tropical agroforestry systems larly through studying the relationships between system components over time.
in the 1980s, but soon became commonplace in temperate agroforestry. The They are also useful as decision-support tools for identifying best management
advances we have made in our understanding have helped improve the productivity options for attaining optimal production. We have made some progress in this
and sustainability of agroforestry systems over that of traditional forms of agrofor- regard; however, major challenges are still ahead in making these decision-support
estry by designing new systems. tools, including making models easily accessible and available for landowners
and practitioners.
The Way Forward
Outline of the Book
Recent books that cover the fundamental ecological interactions and processes in
So, the question naturally arises; why another book on agroforestry? We would
agroforestsy and similar agroecosystems (e.g. Ong and Huxley, 1996; Young, 1997;
argue that the book attempts to fill two of the niches that we identified in the earlier
Huxley, 1999; Ashton and Montagnini, 2000; Vandermeer, 2002; Schroth and
discussion (Develop better i~fomzntion and Develop clecision-s~cpportt ools aizd
Sinclair, 2003; Nair et al., 2004; van Noordwijk et al., 2004) attest to the growing
models). We intend to complement existing infonnation and syntheses by presenting
interest in making use of ecological knowledge as an integral part of agroforestry
the latest body of knowledge from a wide variety of agroforestry systems around
design. Collectively, these references have formed a solid ecological foundation for
the globe. We acknowledge that one book alone cannot fill the niches identified
agroforestry and its way forward. Increasingly, agroforestry systems and practices
earlier. As we advance the ecological science behind agroforestry one study at a
are being designed by taking local and pertinent ecological knowledge and the
time, we will move closer toward making ecological sustainability a global reality
landscape context into account. However, as one would expect, past research has
for agroforestry systems. We will highlight the chapters included in this book in the
made us cognizant of how little we know about the ecology of these systems,
following paragraphs.
especially in the temperate regions. There are more questions than answers and an
This book examines a range of issues that can be addressed or ameliorated using
enormous task lies before us, in terms of dealing with the many challenges of devel-
agroforestry systems in both a tropical and temperate context, highlights how ecological
oping appropriate and acceptable agroforestry systems. We need to appreciate the
understanding allows both improved system design and more effective management
following:
practices and presents a series of latest developments in improving ecological under-
1. Recognize limited crizdelstandiizg: Agroforestry systems, whether temperate or standing, including a range of tools for data analysis and modeling.
tropical, are extraordinarily complex. Most often we extrapolate ecological The eight chapters (Chapters 2-9) included in Section 2 bring together a broad
information from site or specific experiments. We all know we rarely have range of examples and draw out underlying principles relating to resource allocation
perfect or complete information for designing or managing agroforestry sys- and related ecological processes aboveground. Oelbemann and Gordon, for example,
tems, but need to be cognizant and cautious about the potential limitations and describe the ecological processes in integrated riparian management systems in
consequences of designing agroforestry systems based on limited knowledge. Chapter 2. The development and design of shelterbelt agroforestsy systems and the
Adaptive management is the key. underlying ecological principles and functions are discussed in detail by Mize et al.
2. Develop better information: There is still critical need for site and species in Chapter 3. Forage production in a temperate silvopastoral system and legume
specific information on many agroforestry systems from both temperate and cover crop production in a tropical silvopastoral system, both in relation to light
tropical regions of the world. Better information on and understanding of the intensity, are examined by Feldhake et al. and Baligar et al. in Chapters 4 and 5,
basic ecology of individual species (autecology) and species interactions respectively. The next two chapters provide examples of how trees modify the
(community ecology) and species-abiotic interactions (ecosystem ecology) will microclimate in agroforestry systems using alley cropping as a model system.
enhance our ability to make these systems ecologically sustainable. Tactical Zalnora et al. (Chapter 6) explains the role of light in determining crop yield
decisions on management issues will become easier with a solid ecological in a temperate alley-cropping system and Shapo and Adam (Chapter 6) examine a
understanding of the system as a whole. number of microclimatic parameters in a tropical alley-cropping system in northern
8 S. Jose and A.M. Gordon I Ecological Knowledge and Agroforestry Design 9
Sudan with respect to their influence on crop yield. The last two chapters deal with
Gold M.A., Rietveld W.J., Garrett H.E., and Fisher R.F. (2000) Agroforestry nomenclature,
resource allocation and use in two Central American agroforestry systems. While concepts, and practices for the USA, pp. 63-78. In: Garrett H.E., Rietveld W.J., ilnd Fisher
Bellow et al. (Chapter 8) explore resource capture and productivity of fruit-based R.F. (eds) North American Agroforestry: An Integrated Science and Practice. American
agroforestry systems in highland Guatemala, Vaast et al. (Chapter 9) report on the Society of Agronomy Inc. Madison, WI, 402 pp.
Grime J.P. (1973) Competitive exclusion in herbaceous vegetation. Nature 242:344-347.
biophysical interactions that define productivity of coffee under shade trees.
Huxley P. (1999) Tropical Agroforestry. Blackwell Science, London, 371 pp.
Section 3 has four chapters (Chapters 10-13) that deal with resource allocation
Jose S., Gillespie A.R., Seifert J.R., and Biehle D.J. (2000) Defining competition vectors in a
and related ecological processes belowground. In Chapter 10, Kiparski and Gillespie temperate alley cropping system in the mid-westem USA. 2. Competition for water. Agrofor.
explain how the relative importance of below versus aboveground processes shifts Syst. 48:41-59.
as a temperate alley-cropping system involving black walnut (Juglans nigra) and Nair P.K.R., Rao M.R., and Buck L.E. (eds) (2001) New vistas in agroforestry: A compendium for
the 1st World Congress of Agroforestry, 2004. Kluwer, Dordrecht, The Netherlands, 480 pp.
maize (Zea mays) ages. Gowda and Kumar (Chapter 11) test the hypothesis that
Olson R.K., Schoeneberger M.M., and Aschmann S.G. (2000) An ecological foundation for
root competition in multispecies systems such as homegardens depends on tree
temperate agroforestry, pp. 31-62. In: Garrett H.E., Rietveld W.J., and Fisher R.F. (eds) North
traits rather than resource availability. Establishment of Cordin dodecandrn with American Agroforestry: An Integrated Science and Practice. American Society of Agronomy,
Bixu olsllana on calcareous soils in Yucatan, Mexico under varying degree of water Madison, WI, 402 pp.
availability is investigated in Chapter 12 by Reuter et al. And finally, in the last Ong C.K. and Huxley P.A. (1996) Tree-Crop Interactions: A Physiological Approach. CAB
International, Wallingford, UK, 386 p.
chapter (Chapter 13), Mafongoya and Hove synthesize information on the effects
Schroth G. and Sinclair EL. (2003) Trees, Crops, and Soil Fertility: Concept and Research
of polyphenols on nitrogen use by crops and ruminant livestock, highlighting simi-
Methods. CAB International, Wallingford, UK, 437 pp.
larities and differences between crops and livestock systems and discussing the Sinclair F.L. (1999) A general classification of agroforestry practice. Agrofor. Syst. 46: 161-180.
underlying principles of strategies that are available to farmers to improve nitrogen Vandermeer J. (2002) Tropical Agroecosystems. CRC Press LLC, Boca Raton, FL, 268 pp.
use efficiency. Van Noordwijk M., Cadisch G., and Ong C.K. (2004) Belowground Interactions in Tropical
Agroecosystems: Concepts and Models with Multiple Plant Components. CAB International,
Section 4 describes important analytical and modeling tools used in agroforestry
Wallingford, UK, 440 pp.
system design and evaluation. Kimrnins et al. examine the role of ecosystem-level
Vogl R.J. (1983) A Primer of Ecological Principles. Pyro Unlimited, Cypress, CA, 172 p.
models in the design of agroforestry systems in Chapter 14. They describe a family Young A. (1997) Agroforestry for Soil Management, 2nd edn. CAB International, Wallingford,
of models based on the hybrid simulation (FORECAST) approach to prediction and UK, 276 pp.
scenario analysis. The approach focuses on the combination of experience and
process-level understanding as the basis for simulating and evaluating alternative
agroforestry designs over various spatial and temporal scales, and the possible con-
sequences of climate change. Measurement and simulation of light availability in a
tropical agroforestry system with coffee is the subject of Chapter 15 by Righi et al.
and Camllo and Jordan (Chapter 16) discuss about how the addition of green
manure influences the soil community and how this change in turn influences nitrogen
mineralization patterns in a temperate alley-cropping system. The above- and
belowground interactions with trees and associated crops of Pennisetctm glauccim
and Sorghum bicolor are investigated in an agroforestry parkland system in Burkina
Faso using the WaNuLCAS model in Chapter 17 by Bayala et al.
Finally, Section 5 provides an overview of the current state of ecological knowl-
edge that is useful in designing agroforestry systems. Further, it identifies existing
gaps in our knowledge base and outlines a collaborative approach that is necessary
to strengthen the ecological research in agroforestry.
References
Allen S., Jose S., Nair P.K.R., Brecke B.J., and Nkedi-Kizza P. (2004) Safety net role of tree roots:
Experimental evidence from an alley cropping system. For. Ecol. Manage. 192:395407.
Ashton M.S. and Montagnini F. (2000) The silvicultural basis for agroforestry systems. CRC
Press, Boca Raton, FL.
Section 2
Resource Allocation in Agroforestry
Systems: Aboveground Processes