Native grasses of South Western Australia

As south Western Australia has no significant areas of native grass pastures remaining, discussion is limited to their extent and composition in the pas

Fragility, health and design: Conceptual challenges for Australian Agriculture

This paper examines three conceptual challenges to the development of agriculture for theAustralian environment – the claim that Australia’s landscapes are fragile, the question ofassessing the health of landscapes and the degree to which agricultural landscapes can bedesigned. It is suggested that the fragility of Australia’s landscapes is a cultural rather thangeographical description and reflects unmet human expectations rather than inherentproperties of the continent. The usefulness of current approaches to measuring landscapehealth is questioned, particularly those based on the absence of agriculture such as the oneadopted by the National Land and Water Resources Audit. On the question of design, it issuggested that governments and markets will have the ultimate say on the shape of Australian agriculture over science-based approaches to design

Agroforestry for water management in the cropping zone of southern Australia

Agroforestry has been advocated as a means of managing excess water that has accumulated in the agricultural landscape of southern Australia since clearing of native vegetation. This article examines the feasibility and profitability of agroforestry systems designed to manage rising, saline watertables. A framework for Australian conditions is described that considers the interactions between trees, crops and their below ground environment and how they influence water use, crop yield and profitability. Data is presented from a study of a commercial scale agroforestry system under ideal conditions where trees have access to a shallow fresh water table. The discussion is then broadened to encompass soil, relief and ground water conditions more typical of the southern Australian cropping zone. The relative merits of segregating, integrating and rotating trees with crops are then examined. It is concluded that, in most cases, trees would need to be widely dispersed over a significant proportion of the landscape to manage deep drainage and salinity. Agroforestry is therefore only likely to be an effective solution to water management where trees can compete directly on commercial terms with conventional agriculture. Given the generally low rates of biomass accumulation in semi-arid woody species, this presents a significant challenge for agroforestry in the cropping zone of southern Australia

Reconciling agriculture and nature conservation: toward a restoration strategy for the Western Australian wheatbelt

In this chapter we suggest that a description of the basic nature and extent of revegetation necessary to overcome land degradation in the wheatbelt of Western Australia can be arrived at systematically. In doing so we attempt to focus attention away from a perceived conflict between production and conservation and towards the common ground shared by both i.e., the restoration of basic ecosystem functions. Rather than asking how to protect the existing production system, this approach asks firstly: what form does the vegetative cover of this region need to take to best ensure its long-term health? And secondly: what are the potential economic values of such vegetation that might motivate its establishment? This analysis suggests that in the order of 500 million to one billion trees and shrubs are required over the 15 million hectares of cleared land. It is also suggested that if the revegetation is concentrated into belts and planted with attention to landform and aspect, the production of crops and pastures could be enhanced while Simultaneously providing wildlife habitat and permanent protection against land degradation as well as providing some commercial products from indigenous woody plants. Actual and potential economic and nature conservation values o

Nitrogen isotope fractionation in the fodder tree tagasaste (Chamaecytisus proliferus) and assessment of N2 fixation inputs in deep sandy soils of Western Australia

Nitrogen (N) isotope fractionation and symbiotic N fixation were investigated in the shrub legume tagasaste, growing in the glasshouse and field. In a pot study of effectively nodulated plants supplied with 0, 1, 5 and 10 mM nitrate [stable isotope 15N (δ15N) of 3.45‰], the δ15N of dry matter N of fully symbiotic cultures indicated a greater isotope fractionation during distribution of N between nodules, stems, leaves and roots than for N2 fixation itself, with whole-plant δ15N being near zero (–0.46 to 0.42‰). Regardless of whether plants were field-grown, pot-cultured, fixing N2 or utilising mineral N, woody stems were depleted in 15N relative to all other plant parts. The similar orders of ranking of δ15N for plant components of the nitrate-treated and fully symbiotic plants, and a general increase in δ15N as plants were exposed to increasing concentrations of nitrate, indicated that N isotope fractionation can be accounted for, and thus not undermine 15N natural abundance as means of measuring N2 fixation inputs in tagasaste trees. In pot culture the percentage of plant N derived from the atmosphere (%Ndfa) by symbiotic N2 fixation fell from 85 to 37% when the nitrate supply was increased from 1 to 10 mM, with evidence of nitrate N being preferentially allocated to roots. δ15N natural abundance assessments of N2 fixation of 4-year-old trees of field-grown tagasaste in alley (550 trees ha-1) or plantation (2330 trees ha-1) spacing were undertaken at a study site at Moora, Western Australia, over a 2-year period of shoot regrowth (coppicing). Cumulative N yields and %Ndfa were similar for trees of alley and plantation spacing, with much less coppice N accumulation in the first compared to the second year after cutting. Scaling values from a tree to plot area basis, and using a mean %Ndfa value of 83% for all trees at the site, inputs of fixed N into current biomass plus fallen litter over the 2 years of coppicing were calculated to be 83 kg N ha-1 year-1 for the alley and 390 kg N ha-1 year-1 for the plantation spacing. Although the plantation tagasaste fixed 587 kg N ha-1 in the second year, close to the maximum value reported in the literature for any N2-fixing system, this should not be seen as typical where the trees are used for animal production, since grazing and cutting management will substantially reduce productivity and N2 fixation input

Emergy analysis of three cropping systems in south western Australia

Wind erosion and rising water tables are serious threats to the ecological sustainability of annual plant-based farming systems on deep, infertile sandplain soils in southwestern Australia. In this study, an annual cropping system was compared with two novel perennial plant-based systems designed to address these threats in terms of their use of renewable indigenous resource, their use of non-renewable indigenous resources, their purchased inputs of energy and materials, and profitability. The farming systems were an annual lupin/wheat (Lupinus angustifolius L./Triticum aestivum L.) crop rotation, a plantation of the fodder tree tagasaste (Chamaecytisus proliferus L.) and an alley cropping system in which the lupin/wheat rotation was grown between spaced rows of tagasaste trees. Flows of energy and materials between the environment and the economy were identified for each farming system and the natural and human activity involved in generating inputs as goods or services then valued in terms of the equivalent amount of solar energy required for their production using the emergy method of Odum [Ecological and General Systems: An Introduction to Systems Ecology. University Press of Colorado, revised edition of Systems Ecology, 1983, Wiley, New York, 644 pp.; Environmental Accounting: Emergy and Environmental Decision Making. Wiley, New York, 370 pp.]. The results showed that the two largest energy flows in the conventional lupin/wheat cropping system were wind erosion and purchased inputs of phosphate. The renewable component of production was 15% of total flows in the lupin/wheat system, 30% in the alley cropping system and 53% in the tagasaste plantation. The annual net income from the plantation system was nearly four times higher, and from alley cropping 45% higher, than from the lupin/wheat rotation. This analysis suggested that once the two agroforestry systems were fully established, the tagasaste plantation was the most efficient at transforming natural resources into goods and services and the most profitable, while the lupin/wheat system was the least energy efficient and the least profitable

Agriculture as a Mimic of Natural Ecosystems

Many current agricultural systems are not sustainable in the long-term due to land degradation and the high levels of resource inputs involved in production. In Australia there is an increasing perception that achieving sustainable agriculture will require dramatic departures from current practices. This workshop, convened in Western Australia, brought agriculturalists and ecologists from around the world to explore the concept of natural systems agriculture which suggests that natural ecosystems can serve as models from which we can develop sustainable agricultural systems

Governance design for adaptation and transformation in social-ecological systems

Conference Aim and Vision: Resilience, as the capacity to deal with change and continue to develop, relates to ecological dynamics and governance questions associated to specific resource systems (agroecosystems, fisheries, forests, rangelands, marine and freshwater ecosystems), and to global issues such as biodiversity conservation, urban growth, economic development, human security and well- being. Human societies are an integral part of the biosphere and sustainable social development depends on the continuous generation of essential ecosystem services. Thus ecosystems change is often considered as one factor decreasing social and ecological resilience. over the past century we have entered a new era where human activities have emerged as a main force shaping the biosphere from local to global scales, as reflected by climate change, vulnerability in the economic system, large losses of biodiversity, and irreversible changes in ecosystems. This is also a time of unprecedented development challenges: intransigent poverty and inequality constitute a major threat to human welfare and to planetary sustainability. There is an increasing interest in the transformability of social ecological systems i.e., the capacity of society to change the system’s state variables when current trajectories become untenable. But a critical dilemma faces humankind: how can more equitable and beneficial social development paths be stimulated in light of these challenges? The objective of resilience 2014 is to explore and reinforce the multiple links between resilience thinking and development issues. The concepts of adaptation, Transformation and development are central and common to several research communities, including resilience in social and ecological systems, ecological economics, environmental change, Farming Systems (among others). Besides, the term resilience is now being used more widely in policy circles and policy debates. Beyond the academic sphere, business and development communities are increasingly using the resilience concept in their discourses. By now they have built their own sets of notions and practices of resilience, although these meanings sometimes may be at odds with scientific interpretations of resilience. Focusing on resilience, but firmly rooted in the belief that a diversity of approaches can inform each other, the conference will offer the opportunity to articulate and debate their specific paradigms, concepts and methodologies. complex problems require diverse approaches that can generate a constructive debate, and eventually lead to more suitable solutio