Manu Saunders writes: Growing just one crop, known as monoculture, is a relatively easy, common and efficient way to produce food and fibre.
But international research shows that these monocultures can be bad for the environment and production through effects on soil quality, erosion, plants and animals, and ultimately declining crop yields.
Monocultures don’t exist in nature. This diversity of plant species and sizes supports diverse wildlife communities, and this diversity supports ecosystem services such as pollination and biological control.
When this diversity disappears, the results can be disastrous. The Dust Bowl years on the American Great Plains showed us what can happen when natural ecosystems are overwhelmed by intensive, single-crop farming.
Large fruit tree plantations differ from field crops because they are permanently embedded in the landscape for more than 10 years. Therefore, they may have more serious, long-term impacts on the environment than an annual crop.
If a plantation is inhospitable to an animal species, it won’t be able to move through the plantation to find food or shelter. This essentially creates a landscape barrier for that species.
Such effects have been found on bird, ground beetle, reptile and marsupial species living in landscapes dominated by pine plantations in south-eastern Australia.
Unlike pine trees, fruit trees rely on insect pollination, an ecosystem service, to produce fruit. With all the agricultural stressors influencing honey bee colony losses in other parts of the world, understanding how wild pollinators respond to farming practices is critical.
In the mallee woodlands and shrublands of southern Australia, probably one of the most understudied and important ecosystems for conservation, almond plantations are rapidly expanding.
Natural ecosystems like mallees are rich in diversity, unlike the monocultures that replace them.
Research from California on commercial almond plantations shows that numbers of wild pollinator and parasitoid insects (unmanaged insects that enhance yields through pollination and biological control) increased with plant diversity..
What does this diversity mean? Monoculture crops are intensively managed to remove as many plants that aren’t crops as possible. In the middle of a monoculture almond plantation, for instance, you will see little else but almond trees and bare soil for hundreds of hectares around you.
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A sustainable farm isn’t just efficient to manage or designed to produce maximum yields per hectare. It also depends on conservation of biodiversity, ecosystem function and diversification of crops and/or livestock.
Research and development of agroecological systems are now internationally recognised as vital to sustainable food and fibre production.
With our unique natural environment and strong agricultural communities, Australia is uniquely-placed to contribute to the global discussion on sustainable agriculture.