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Rural Industries Research & Development Corporation
Summary of full report
by Larry Geno and Dr Barbara Geno
May 2001 RIRDC Publication
No 01/34
RIRDC Project No AGC-3A
Executive Summary
This innovative research project was funded under the Organic Produce Program of the Rural Industries Research and Development Corporation. Under the guidance of an industry developed five year R & D plan, RIRDC began funding research in 1998 in 7 sub-programs: communication and education, conversion processes, organic systems design, soil management, pests and diseases, plant and animal nutrition and market development.
In the 1999 cycle, RIRDC and its industry advisory panel approved funding under the systems design sub-program to Larry and Dr Barbara Geno of Agroecology Associates consultants. This sub-program recognises that most Australian production land use systems are largely an artefact of the importation of western science and economics, European industrial, monoculture, management approaches, and production systems that evolved in European conditions. RIRDC’s Organic Produce Advisory Committee believes that significant redesign of commercial production systems will be necessary to adapt to the different biophysical conditions found on the Australian continent.
The project accepts the extensive evidence already present regarding the failure of industrial monoculture approaches to provide for ecologically sustainable land use. There is no need to further detail fossil fuel energy reliance, net energy imbalance, environmental impacts, rural decline, and food quality issues that have emerged. Clearly, solutions are needed that maintain or increase food and fibre production in Australia. It is quite likely this will be achieved on a reduced land base with the use of fewer external resources in the future and needs to be without the current deleterious side effects. One solution may be a greater understanding and implementation of polyculture practices for agricultural intensification.
An extensive literature review of over 250 articles and books was conducted over a wide range of literature in subjects pertinent to polyculture: multiple cropping, permaculture, agroforestry, and intercropping in traditional peasant agriculture and current industrial production. While the practice and content of polycultures emphasise plant crop components, the overriding principles and supporting theories apply as well to forestry, aquaculture, and animal production systems. Since the ecological and physiological processes and theories generally arise from the study of natural ecosystems, polyculture offers an integrating bridge between natural and human systems, conceptually and on-the-ground. As well, the field offers an effective bridge between ecologists, agronomists and resource managers.
The literature review represents the first time the diverse threads of research have been drawn together to apply to the challenge of sustainable land use. The research strategy was generously inclusive, rather than exclusive because many different disciplines, cultures, and climatic situations contribute to this body of information.
After establishing working definitions of polyculture terms and their evolution through time, it was shown that they all contribute to the basic study of polyculture: the interaction of crop components in time and space.
As a relatively unknown area of study, a rationale for researching polyculture was advanced. It was shown that food production has always been primarily polycultural, from primitive hunting and gathering to current third world house gardens and managed agroforests. For 98.5 % of farming history, humans have produced food from integrated polycultures. In both the first and third world, polyculture practices remain important and the majority of current world farmers depend on multi-species production for their livelihood. Evidence emerged of the growing interest in polyculture indicated by the increasing amount and diversity of the literature. Briefly, the known problems of industrial monoculture practices, the differences between monoculture and polyculture production, and the general advantages of polyculture production were addressed, concluding that it was useful to study polyculture because it might offer a better way to produce food, fin and fibre.
Accepting that sufficient rationale exists for studying polyculture approaches, the benefits of polycultural practices were elucidated by explanation of their underlying mechanisms and theory. Extensive individual case studies and broader review papers provided evidence that polycultures yield more from smaller areas and as an approach to agricultural intensification they suffer less than energy, gene, or expertise intensive strategies to increase production. Their yield is more stable over space and time than monocultures in terms of income level, stability and risk. Polycultures generally showed advantages while highlighting methodological problems in assessing subsistence versus market values and the role of full cost accounting in addressing benefits and costs. Little was found covering wider social and landscape values excepting the benefits of polycultures in addressing biodiversity needs.
With an understanding of the benefits of polyculture approaches, the detailed ecological basis for these benefits that arise out of interaction between crops and between crops and environment were addressed.
The report reviewed the range of competitive and complementary interactions and the way they result in polyculture yield advantage and income risk reduction. Relevant ecological theories and their evolution through time were complemented with agronomic studies and the more recent integration of the two fields of science.
The process of resource capture by producing polycultures further explained the mechanisms behind polyculture benefits by looking at environmental resource use, including capture, utilisation, allocation, partitioning and differential use. Both structural and functional interactions were considered over both time and space. It was found that polycultures were more efficient at gathering the essential requirements of light, water, and nutrients than monocultures, particularly when tree based. The subtle interplay between complementarity and competition was seen as an essential feature of polycultures, as it is in natural ecosystems.
As many of the benefits arise from, and current research efforts directed toward, the role of polyculture practices in achieving acceptable pest control, a separate section presented this material. By understanding pest dynamics, particularly insects, the mechanisms of polyculture yield advantage were further articulated. Less, but sufficient, research was identified for disease and weed pests, especially the role of alleopathy.
With the foregoing information tools at hand, the report addresses the appropriate polyculture component characteristics and design principles necessary to design or monitor new or existing polyculture systems.
The literature suggested that an increased awareness of existing biophysical conditions, appreciation of pre-existing native ecosystems and that an understanding of ecological theory and agronomic practice would assist in successful polyculture establishment through the notion of agriculture as ecosystem mimic.
The substantial interest in tree crop based polycultures indicated this area to have perhaps the greatest potential in realising polyculture benefits. Of note, it appears the potential to realise polyculture benefits is scale neutral and can be achieved by any size producer, anywhere, with appropriate crop assemblages.
No ‘magic bullet’ is without cost or risk. The research covered risks, barriers, constraints and obstacles to successful polyculture production as physical crop and site differences and challenges to management, labour and mechanisation. As well, the social dimension, since humans are involved, is critical and the constraints preventing wider adoption of polyculture practices were addressed for research and extension, policy, information availability, and other socioeconomic dimensions. Polyculture production demands higher producer involvement and management expertise yet suffers from a lack of research and education efforts.
Agricultural breeding has focused its efforts in a direction that means current crop varieties may not suit polyculture practices. In the rush to implement successful agroforestry systems, the absence of information has caused failures, but not as many failures as have resulted from inattention to socio-economic factors. Polycultures were seen as more difficult to manage under existing mechanisation, but possible. Increased labour needs for polyculture could be seen as a barrier or as an employment opportunity. Considerable further research and extension will be needed but the very way science is currently done may be a constraint to expanding polyculture practices. Still, the conclusion was that there are few barriers that could not be overcome with determination.
A brief exploration of the popular press in Australia indicated that organic producers might be innovating in the establishment and operation of polyculture systems. Following the literature search, an extensive survey of 7000 organic and transition producers was conducted through organic certification agencies and the national alternative agriculture press. Unfortunately, less than half of the very low 1% response to the survey showed serious polycultural practices.
Despite having a sample too small for representativeness or statistical treatment, useful empirical information of an indicative sort is presented as tables and summarised. As a communication tool, two scenarios of polyculture production, temperate and tropical were developed from principles, guidelines, strategies and practices arising from both the literature and survey responses.
A final table of polyculture
production as characterised by the literature and empirical survey as emergent
properties, polyculture principles, practical strategies and expected benefits
and risks indicates a need to demonstrate successful polycultures in a
variety of climate and cropping systems and to undertake education efforts
to enable Australian primary producers to implement polyculture systems
to become more environmentally sound, better off financially and more globally
competitive under ecologically sustainable development (ESD) and full cost
accounting environments.
 
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