Urban encroachment on agricultural land

Anyone who has lived at the edge of one of Australia’s expanding cities knows that it isn’t the edge for long. According to one of my neighbours, the suburban block I live on was once (in the 50s) part of the southern suburban boundary with naught but agricultural land beyond. The inner suburban boundary is now at least 6 km further south and the outer suburban boundary might be 30 km further from the 1950s boundary.

So why does this happen?

The outward march of Australia’s suburbs is due to a number of things all working together. Firstly, population in cities has grown (and continues to grow). Increasing populations need housing and land at the outer reaches of cities is a logical place for houses to be built. Secondly, cars and mass transit mean that people are able to travel further to commute between places. A family might sacrifice the convenience of living near their workplace for the benefit of a larger house in the suburbs. Thirdly, land development near your farm often increases the value of that property – increasing land rates and generating an incentive to sell your property. Finally, and most importantly, the value of agricultural land near cities has not been thoughtfully assessed and State governments (and local governments for smaller cities and towns) have not been proactive in realising and protecting this value.

Why is agricultural land near cities important?

Firstly, think about why Australia’s cities were established in their particular spots. Many of them are in positions where fresh water was available, and the soil was ‘good’ for growing food, meat, and fibre. These good soil sites are actually relatively rare in Australia, as many of our soils are ancient or are formed from ancient rocks – old soils that are tired and not very good at intensively growing plants. When our cities grow outward, the good soils get buried under houses and roads, and are no longer used for what they did best – supporting ecosystems and people with resources.

The soil the house I currently live on is a neutral to slightly alkaline, loamy to heavy textured soil most likely formed on alluvial sediments deposited during flooding of one of the local creeks. An excellent soil for market gardens but ruined now by groundwater contamination from the historic actions of local industry. In the same vein, many sites around Adelaide have pockets of black cracking clay – awful for building, excellent for agriculture. Again, many of these sites are now under houses and therefore unavailable for what they did best.

Why should you care, and what can be done?

Urban encroachment on agricultural land affects your life, even if you don’t realise it. It pushes farms further away from population centres, increasing the freight costs of produce. It pushes farms off of good soils or out of good locations (weather, water, access, etc.) often increasing the costs of production. City footprint expansion also affects you indirectly through things like the provision of public transport and road infrastructure – an ever-increasing area of service means an ever-increasing cost burden to the public.

So what can you do? Support your community when a developer comes knocking on your council’s door. Support your agricultural businesses when people in that new development down the road start complaining about the farm noises and smells. And support urban planners when they suggest sensible growth limits on the suburbs around your town or city.