Updated: Oct 18, 2021
Ever wondered why the soils in old goldfields areas of Victoria seem to be hard and rocky? Why it is hard to get a shovel in and to get plants to grow? Jess gave a webinar to a local Landcare group in 2020 on just those things.
Soil usually consists of organic material such as dead and decaying plants and animals; mineral containing materials such as rocks; as well as water, air, living organisms, and essential plant nutrients. Together, all of these things make a healthy soil that has, creates and sustains life.
For anyone who has been to the goldfields in Victoria, you may have noticed the sad rocky soil. In fact, people always have a good laugh when I tell them I am a soil scientist working in the goldfields. They say “Ha ha! What soil?” They aren’t wrong; there isn’t a lot of soil left after the gold mining finished.
The soil in the goldfields used to be very different. Dja Dja Wurrung, the custodians of the unceded land I live and work on, talk about “upside-down country”; that the land is sick from erosion, salinity and heavy metals. Bruce Pascoe also talks about how the soil in Victoria was like a sponge with lots of organic matter, used in cultivation by First Nations people. From First Nations knowledge, we know that the soil in the goldfields prior to colonisation was almost certainly very different to what it is now.
The goldrush in Victoria, Australia changed our soils for the foreseeable future. The peak of the goldrush occurred between 1851 and the late 1860s in Central Victoria (Map 1). Prominent towns included Ballarat and Bendigo. There was a huge impact to the soils and environment in the local area not only from gold exploration but also from the huge numbers of people who came out to the goldfields to make their fortune. Castlemaine, where I live, has a population of <10,000 people today including all the old mining villages. At the peak of the goldrush it was closer to 50,000 people! I can hardly begin to imagine the huge number of people living in huts, tents, and other rough shelters trying to make their fortune, or simply just trying to get by.
It was the rush of people that irreversibly altered our soils. Gold miners dug holes and tunnels all through the hills and creeks of the area, turning the soil up-side down. People removed vegetation, either for gold fossicking or to provide fuel, warmth, building supplies or to use in industry. The gold diggings and lack of vegetation meant soil became unstable, and the soil was washed into the creeks and rivers through successive rainfall and erosion events. Researchers have found that much of the soil went into the Loddon and Murray Rivers, creeks, floodplains and further away. At the time there was no need to manage erosion and to rehabilitate the land, whereas regulation now requires both.
In current times, soils in the goldfields are often described as skeletal (very thin) or no soils. The soils that are left after the goldrush often have no topsoil, many rocks, low organic matter, don’t hold a lot of water, have poor nutrient cycling and soil biodiversity, and poor plant growth. Our soils do have forests growing on them again, demonstrating that our soils and environment are recovering, slowly.
From a Landcare and rehabilitation perspective, we can help to recover our soils. We can plant as diversely as possible to kick-start ecosystem recovery. We can also use mulch to help hold water in the soil, which helps faster restoration of nutrient cycling and plant growth. With more water and plants, we have more carbon and soil biology and we start to improve the health of our soils to sustain life.
* Map from: Hough, Megan & Bierlein, Frank & Ailleres, Laurent & Mcknight, Stafford. (2010). Nature of gold mineralisation in the Walhalla Goldfield, southeast Australia. Australian Journal of Earth Sciences. 57. 969-992. 10.1080/08120099.2010.511262.