How do agriculture and food production both depend on and degrade the ecosystems that support them?
Explain how agriculture, aquaculture and food production depend on ecosystem processes, and describe the environmental impacts of intensive land and water use.
How farming and aquaculture depend on soil, water and pollination, and their impacts including soil degradation, eutrophication and salinity, with Tasmanian salmon and agriculture examples, for TASC Environmental Science Level 3.
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What this dot point is asking
This dot point asks you to explain how producing food depends on natural ecosystem processes, and to describe how intensive agriculture and aquaculture damage the very systems they rely on. You should connect food production to soil, water and pollination, and use Tasmanian and Australian examples to show impacts such as soil degradation, nutrient pollution and salinity.
Food production depends on ecosystems
Agriculture is not separate from nature; it is the management of ecosystems to harvest energy and nutrients for human use. Crops depend on healthy soil that holds water and nutrients, on the water cycle to supply rainfall and rivers, on decomposers and nutrient cycling to maintain fertility, and on insects and other animals to pollinate many flowering crops. Aquaculture, the farming of fish and shellfish, depends on clean, oxygen-rich water and on the marine food web. Because food production relies on these services, degrading them undermines future productivity.
Impacts on soil
Intensive cropping and grazing place heavy demands on soil. Removing vegetation exposes soil to wind and water erosion, stripping the fertile topsoil that took centuries to form. Continuous cultivation can reduce soil organic matter and structure, lowering its ability to hold water and nutrients. Compaction by machinery and livestock reduces the pore space roots and soil organisms need. In Australia, decades of clearing and overgrazing have caused widespread erosion, and rebuilding degraded soil is slow and expensive.
Impacts on water
Agriculture is the largest user of fresh water in Australia, mostly for irrigation. Diverting water from rivers for crops reduces environmental flows, harming wetlands and aquatic species, as seen in the long-running pressure on the Murray-Darling Basin on the mainland. Fertilisers and animal waste washed off farmland carry nitrogen and phosphorus into waterways, driving eutrophication. Pesticides can poison non-target species and accumulate in food chains.
Aquaculture creates its own water impacts. Tasmania's salmon industry is economically important but concentrates large numbers of fish in coastal waters, where uneaten feed and fish waste add nutrients to the water and can deplete oxygen on the seafloor beneath pens. Managing stocking density, fallowing lease areas and monitoring water quality are used to reduce these impacts, and the industry is closely scrutinised in sensitive waterways such as Macquarie Harbour.
Salinity and land degradation
Clearing deep-rooted native vegetation for shallow-rooted crops and pasture allows more water to seep below the root zone, raising the water table and bringing stored salts to the surface. This dryland salinity has degraded large areas of Australian farmland, killing vegetation and damaging soil and waterways. Salinity is hard to reverse once established, which is why prevention through revegetation and careful water management is emphasised.
Towards sustainable food production
Sustainable practices aim to keep producing food while protecting ecosystem services. These include rotating crops and using cover crops to maintain soil organic matter, minimum-tillage farming to reduce erosion, matching fertiliser application to crop needs to cut runoff, fencing and revegetating waterways, integrated pest management to reduce chemical use, and careful siting and fallowing of aquaculture leases. Tasmania's relatively cool, wet climate and clean image support premium agriculture, which gives producers a commercial reason to protect environmental quality.
Bringing it together
To answer this dot point well, explain that food production depends on soil fertility, water, nutrient cycling and pollination, then describe the main impacts of intensive agriculture and aquaculture: soil erosion and degradation, water over-extraction and pollution, eutrophication, pesticide harm and dryland salinity. Use Tasmanian salmon aquaculture and Australian salinity or the Murray-Darling Basin as examples, and finish with sustainable practices that protect the services production relies on.