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Soil health
Soil health and the design of sustainable agro-ecosystems
Linear systems / cyclical systems
Genetic modification/engineering
Features of sustainable agro-ecosystems
Existing sustainable agro-ecosystems
Who will begin the necessary changes?
Civilization to date has consistently been associated with the exploitation of formerly fertile soils and its conversion into vast areas of degraded, saline and/or eroded soil capital. As the availability and affordability of the oil on which our societies and much of the world’s current 6.5 billion people depend declines, we can either join past civilizations in the archeological record or rapidly re-design productive agro-ecosystems based on sustainable natural processes.
Linear systems / cyclical systems - Unless we rapidly transform our agriculture and food industry from its current simple, linear, exploitation, consumption and waste of natural and social capital into a more efficient industrial ecology based on the recovery and recycling of resources we risk major food and material shortages and social crises within decades.
Fortunately, highly productive and profitable options exist for doing this. Even without the decline in oil, the adoption of sustainable agricultural systems will be essential if we are to restore our already degraded natural soil capital as well as enhance the resilience of agro-ecosystems to the increasing extremes resulting from climate change.
Topsoil loss - Critical to achieving this imperative will be protecting and restoring the ‘health’ of our soils. Most of our farming systems are still losing 50 tons of topsoil for every ton of grain produced. Agriculture is still quarrying topsoils 40 times faster than it is able to be naturally reformed. The earth only has a finite area suitable for farming and we are already using most of this.
Attributes of soil health - Our future will depend on how effectively and quickly we can restore and enhance soil ‘health’, which includes the physical, chemical and biological condition of soils that optimizes their bio-productivity as well as the biological systems, symbioses and cycles on which this bio-productivity depends. Soil health is derived from the soil’s structure, root proliferation, water infiltration and holding capacities, cation exchange capacity and microbial diversity.
Our future will depend on how effectively and quickly we can restore and enhance soil ‘health’. We need to consider the physical, chemical and biological condition of our soils in order to optimize their bio-productivity in sustaining plant and animal production as well as the biological systems, symbioses and cycles on which this bio-productivity depends. These components and processes create and determine the structure, root proliferation, water infiltration and holding capacities, cation exchange capacity and microbial diversity of soils and underpin its sustainability and productivity.
What soil health can provide - Only through understanding and intelligently managing these processes governing soil health in ago-ecosystems re-designed for sustainability will our civilization have the possibility of:
- Restoring the productivity of our critical natural soil capital asset.
- Sustaining primary bio-productivities and food securities.
- Secure the ongoing availability and quality of essential eco-system services such as water.
- Building adequate resilience into our agro-ecosystems to buffer the impacts from global warming, and
- Maintaining economic and social viability in a post oil industrial ecology.
Green revolution - Although the green revolution was able to defer previous food security crises through high inputs of genetic, cultivation, fertilizer, irrigation and pesticide technologies, the improvements were all based on the addition of high energy and material inputs based on cheap oil. More seriously the continued productivity of these advanced agricultures was made increasingly dependent on ever higher oil-based energy inputs as soils were exploited faster and the decline of ‘soil health’ was accelerated. As these agricultural systems were selected and refined to maximize crude growth through the exploitation of the added irrigation and fertilizer inputs, their productivity is often totally dependent on maintaining these high oil-based inputs. Their net energy yield is often very low, even 10%, of the oil-based energy inputs required to maintain them and they may be totally unsuited and unable to survive in a post oil agri-economy.
Genetic engineering - Although some hope that genetic engineering, like the previous green revolution, will solve the coming food security crisis it too risks distracting us from natural reality. Plant life has evolved for over 3.8 billion years through optimizing the capture, distribution and use of biochemical stored solar energy in interacting bio-systems, symbioses and ecologies. Sophisticated distributions, symbioses and balances have evolved for a reason: to optimize the overall function, productivity and sustainability of that total system. It may be naïve for genetic engineering to think that by artificially modifying isolated parts of such systems to alter a distribution process that it can effect sustained yield or systems improvement relative to the 3.8 billion years of system optimization through evolution.
Understanding whole agro-ecosystems - Rather than looking for the next ‘magic bullet’ through artificial gene manipulations, our focus needs to be in understanding and optimizing each ecological system. We need to understand and enhance the processes and symbiotic gene assemblages that nature has evolved to overcome limiting growth conditions and enhance the cycling of essential limiting nutrients so as to increase bio-productivities, yields and the sustainability of natural healthy agro-ecosystems.
Features of sustainable agro-ecosystems - Rather than gene manipulations or expensive artificial inputs the design of such sustainable agro-ecosystems needs to be based on:
- Understanding the key processes governing and limiting the sustainable bio-productivity of each agro-ecosystem.
- Restoring these processes in soils and bio-systems to enhance and sustain their productivity.
- Rebuilding critical cycles within these systems rather than the current exploitive linear use and wastage of internal or imported nutrients and resources.
- Utilizing the unique natural gene pool and symbioses that have evolved in extreme environments throughout Australia to sustain high productivities often on very infertile soils, rather than current GE priorities for creating new patentable but narrow functional capabilities and organisms, and
- Designing agro-ecosystems that optimize and integrate the use of trees, mosaic land management and precision amendments into enhancing their resilience and sustained productivity in the face of global warming realities and extremes.
Existing models of sustainable agro-ecosystems - Models for such sophisticated sustainable strategies are before us in our natural ecology.
Local models -- We simply have to look and learn how we can apply these to bio-mimic our sustainable future. The opportunities are already before us and often highly profitable. For example, Australia currently disposes some 20 million tonnes per year of organic matter in landfills at a direct social cost of over $100 per tonne not counting unspecified major environmental costs and impacts. The ‘City to Soil’ pilot demonstrated most of this organic waste could readily and safely be bio-converted into composts and returned to farm soils at a direct national saving of $2 billion per year as well as through major on-farm dividends. Indeed, as these and wastes contain much of the nutrient capital exported from farm soils, it is essential that they are returned to sustain agricultural productivities and economies. Similar needs and profitable treatment and recycling technologies also exist for urban effluents. Much of the residual urban solid waste can also be source separated, recovered and recycled to industry and agricultural soils.
International possibilities - Challenges and opportunities also arise with regard to global food exports. For over 200 years Australia has quarried and exported its limited soil nutrient capital in rural exports. Unless it finds ways of returning these nutrients its agricultural productivity and capacity to sustain food exports must decline. At the same time urban environments in the food importing countries are often degrading due to nutrient eutrophication from the wastes from the consumed imports. Technologies exist to safely treat and harvest these nutrients so that they can be returned to Australian farmlands to sustain their long-term productivity and role in global food security.
What is preventing change? - Fortunately the processes, understanding, designs and opportunities all exist for us to make this major, profitable but also critical change in sustaining the nutrition, health and bio-productivity of our agro-ecosystems. Only the imperative for national action is missing. Major impediments and inertia is still inherent within the status quo with even the continued use of oil in Australia being estimated to still be receiving subsidies exceeding $10 billion annually. However as the reality of the decline of cheap oil, land degradation and global warming intensify, the un-sustainability of our current approaches and need for urgent change will be clear.
Our options - At the end of the day the survival of this civilization - as with previous ones - will depend on the sustainability of our fundamental, but highly vulnerable, food and water requirements and the capacity of our soils and agro-ecosystems to continue to supply them despite global warming impacts. Whether our civilization survives depends on how well we preserve, restore and manage the bio-productivity of our critically important and finite soil resources. We can either go on degrading our soils, and hence our future, to join previous civilizations in the archeological record, or use our intelligence and knowledge of the processes governing the development and sustainability of our soils and bio-systems to re-design highly productive, profitable and sustainable agro-ecosystems. We must design agro-ecosystems that bio-mimic natural processes governing soil health and the symbiotic fixation and cycling of nutrients not simply their addition and exploitation.
Who will begin the necessary changes? - We have the understanding, the technology and the imperative to effect the needed changes. The question is who will take responsibility so that we will make them in time and before the decline in oil, soil degradation and global warming so compromise our current vulnerable agricultural systems that input dependencies, food insecurities and social chaos take their own course?