Red Ferrosols are ancient Australian soils which formed from the weathering of basalt volcanic rock millions of years ago (Cotching 2015, p. 1). While the flora and fauna of that time are long extinct, Red Ferrosols outlasted many of the challenges, including meteors and climate changes, until the biggest challenge, the humanity, introduced itself. Now Red Ferrosols are in danger of being changed forever, and the ecological harm can only be averted if soil management issues are addressed immediately.
Red Ferrosols are mostly found on the north-west coast and are presented in other areas, such as Scottdale and Ringaroma, in isolated pockets (Cotching 2015, p. 1). Red Ferrosols, the official state soil of Tasmania, are the main source of Tasmania’s iconic foodstuffs (Edis 2013, para. 2). A large part of Tasmania’s potato, vegetables and cereal, dairy industry, sheep production, and meet production depends on Red Ferrosols (Cotching 2015, p. 1).
Red Ferrosols are used to grow potatoes and ginger, and provided with water and nutrients, they become an important agricultural asset. Red Ferrosols have a strongly developed structure: they are structured in such a way that they can hold the water and make it easy for plants to grow (Edis 2013, para. 7). In addition, Red Ferrosols can withstand a lot of agricultural activity. The red to maroon colour of Ferrosols is the result of iron oxides, an inorganic chemical used as a colorant. Iron oxides help Ferrosols adjust to soil aggregates and allow Ferrosols to crumble under duress. The acidity of Red Ferrosols is beneficial for suppressing pests and reduces the need for pesticides.
However, the ancient nature of Red Ferrosols means that they have been exposed to weathering processes for a very long time. As a result, these soils are devoid of many nutrients and minerals necessary for plant growth. Although rich in iron oxide, Red Ferrosols require a large amount of fertilizer to be applied in order to use these soils for agricultural purposes. Research shows that Red Ferrosols are prone to nutrient loss and requires using protective measures, such as cover (McCarroll & Brough 2000, p. 25). If no protective measures are applied, the nutrient loss will significantly increase the rates at which nutrients have to be replaced and eventually reduce nutrient holding capacity (McCarroll & Brough 2000, p. 25).
A bigger issue associated with Red Ferrosols is soil loss and erosion as a result of improper soil management (Cotching et al. 2002, p. 625). In Tasmania, intensively cropped padlocks with Red Ferrosols showed signs of heavy erosion and soil loss over many years (Cotching et al. 2002, p. 625).
The effect was most pronounced on steep slopes, which showed greatly reduced topsoil carbon concentrations. As Cotching and his research team put it, if erosion and soil loss continue at a current rate, they will “inevitably reduce crop yields” (Cotching et al. 2002, p. 625). The degraded structure of Red Ferrosols makes them more difficult to manage “due to a restricted range of soil wetness for tillage operations and can result in low yields” (Belbin & Cotching 2004, p. 1).
Another Research by McCarroll and Brough reviewed the effects of intense cropping on Red Ferrosols. Intense cropping negatively affects Red Ferrosols in several aspects: it causes seepage downslope due to widespread irrigation, leads to physical and chemical decline, and results in poor soil quality, not applicable for farming (McCarroll & Brough 2000, p. 25; Belbin & Cotching 2004, p. 1). Intense cropping has shown to degrade the structure of Red Ferrosols by reducing porosity and aeration, and as a result, limited water trafficability.
This fact, in turn, increases soil strength and cloddiness, and makes it more difficult for plants to take roots (McCarroll & Brough 2000, p. 25). The issue of soil degradation and erosion is further exacerbated by the fact that as non-swelling soils, Red Ferossols do not have the capacity for self-repair (McCarroll & Brough 2000, p. 25). If the effects of structural and chemical decline continue to occur, the ecological damage will eventually make Red Ferrosols not suitable for agriculture.
This fact necessitates a continuous monitoring and assessment of Red Ferrosols and the application of conservation cropping practices. Various soil management practices and techniques can be used to reduce the damage done to Red Ferrosols. While the damage done by intense cropping cannot be repaired by Red Ferrosols, it is not irreversible. Creating vigorous grass pastures on top of Red Ferrosols allows the soils to recover and provide carbon for structural stability (McCarroll & Brough 2000, p. 25). In addition, conservative cropping techniques, such as efficient irrigation management and adjusting water and fertilizer amount to crop demand can help reduce damage done by cropping.
The effects of long-term intense cropping make Red Ferrosols not applicable for agricultural use. Nevertheless, soil management can, to an extent, reverse some of the damage and improve the agricultural quality of soil. Conservative farming practices make sustainable agriculture on Red Ferrosols a real possibility, and help minimize and reverse the ecological damage.
References
Belbin, K & Cotching, B 2004, Soil strength/soil wetness relationships on Red Ferrosols with visually assessed soil structure differences in north-west Tasmania. Web.
Cotching, B 2015, ‘Red soils’ classified as Ferrosols and also known as Krasnozems. Web.
Cotching, W, Hawkins, K, Sparrow, L & Rowley, W 2002, ‘Crop yields and soil properties on eroded slopes of red Perrobols in north-west Tasmania’, Australian Journal of Soil Research, vol. 40, no. 4, pp. 625-642.
Edis, R 2013, The good earth: Thorpdale Red Ferrosol and chip potatoes. Web.
McCarroll, S & Brough, D 2000, Agricultural Land Resource Assessment of Coalstoun Lakes, Queensland. Web.