Farming systems

In the early days of colonisation, farmers adopted the farming systems they had learned in Europe. By the 1870s there was considerable expansion of the rural industries.

The sheep population exceeded 5 million, cattle numbers were over 2 million and some 80,000 pigs were raised on mixed farms. Over 100,000 horses provided traction power for cereal farms, which approached 1.5 million acres. Of this, 1.3 million acres were being used for wheat, which was followed by fallow rotation.

Adapting to Australian soil

With little knowledge of their new farming environment, and no tradition for a permanent farming system, the pioneer agriculturists ran into difficulties. Their crops rapidly depleted the naturally low soil fertility and exposed the soil to erosion.

Yields fluctuated dramatically with the changing seasons and crop diseases, but the declining trend over time threatened the existence of cereal growing over large areas. By mid 1870, the average wheat yield had fallen to 8½ bushels per acre.

Fertilizer and erosion

In their experiments at Roseworthy Agricultural College in the 1880s, Professors Custance and Lowrie showed that the key plant nutrient missing from infertile soils after years of cropping was phosphorus.

Yields improved when superphosphate was applied to the soil. However, it took many years before farmers accepted the need for regular phosphatic manuring in cereal areas.

Cropping rotations were extended to include hay and pasture paddocks, to rest the soil and control weeds and diseases. Prior to the 1940s, fallow was still widely adopted in the rotation with wheat, and these led to enormous issues with wind and water erosion.

In the 1950s, the first steps in halting serious water erosion problems in the higher rainfall areas of the State included:

• dividing land into classes according to its slope
• farm planning.

New crop and pasture rotations

Both subterranean clovers and medics emerged in rotation with cropping, which improved soil structure and fertility via the fixation of atmospheric nitrogen. This ley farming system was widely adopted in the 1950s when wool and meat were in demand.

The use of superphosphate was recognised as critical in the success of this system, and a government-funded subsidy from 1963 to 1973 saw large volumes of superphosphate applied throughout SA. This was responsible for long term benefits in terms of improving soil fertility.

During the late 1960s and 1970s, oilseeds, lupins, triticale, pulses, lentils, canola and vetch were widely introduced into rotations.

Cereal-legume rotations offered interactive benefits of reducing root disease and enhancing soil fertility. Controlling the major root disease, cereal cyst nematode (CCN), with the barley variety Galleon, was a major advance in breeding technology. There was also growing recognition that minimising cultivation, with the ultimate being zero-till, would allow continuous cropping without loss of soil physical and chemical fertility.

During this time, livestock disappeared from many farms. Although in the early years of the 21st century, stagnant cereal prices and improving prices of sheep meat led to a resurgence of grazing flocks on many properties.

Farming systems in SA have changed significantly over the past 150 years and must continue to change, driven by environmental and economic pressures.

Acknowledgements

Author: Bob Holloway