Purpose

Farm machinery has increased significantly in size over the years and can weigh as much as 40 to 50 tonnes, causing soil compaction and soil structure decline. The purpose of controlled farming systems is foremost the minimisation of soil compaction and the associated risks of soil erosion, loss of soil structure, water infiltration rates and productivity, but it is also an effective means to reduce fuel consumption and thus the production of greenhouse gases, particularly if traffic lanes are left untilled and unplanted to optimise traction (Tullberg 2001). Controlled traffic systems require all farm machinery to run on the same track width on tracks either designated mechanically by marker arms or by geographic positioning systems (GPS).

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The concept of controlled traffic systems is based on the observations that plants grow best in soft, uncompacted soil and that tractor wheels run easiest and with the least amount of slip on firm ground (McPhee 2007). Long-term cropping trials have shown that using controlled traffic systems can reduce fuel usage for tillage and seeding operations by more than 75 per cent, while breaking up sub-surface soil compaction in non-traffic areas can increase crop yield by more than 20 per cent (PIRSA 2001).

Components that may be affected:         Soil erosion by wind; Soil erosion by water; Biota; Soil water holding capacity.

Indicator

Percentage of farmers utilising controlled traffic systems

Results

In 1998, the percentage of grain growers using controlled traffic systems to prevent soil degradation was 12 per cent with a further 8 per cent intending to implement controlled traffic systems in the next three years (Watson and Quint 1998, cited in NLWRA 2001).

The chart below illustrates the distribution of the adoption of these practices in the three Grains Research and Development Corporation (GRDC) regions.

^{Source -  NLWRA (2001) Australian Agriculture Assessment 2001 report}

Figure 1: Percentage (%) of grain growers who adopt various management practices to prevent soil erosion.

Table 1. Estimated percentage of farms where the operator is aware of/takes measures to combat degradation problems.

^{Source- ABARE 2001-02 Resource Management Survey.} 

^{Note: RSE = Relative standard error; Population (farms) = 38502,  Sample (farms) = 579}

The 2001-02 Resource Management Survey of the Australian Bureau of Agricultural and Resource Economics (ABARE 2002) estimated that on 37 per cent of broadacre and dairy industry farms in the wheat/sheep zone the loss of soil structure was considered a significant problem, on an estimated 94 per cent of farms loss of soil structure impacted on management, production, returns or costs, on 91 per cent of farms changes were made in 2001-02 in land management practices due to loss of soil structure and 7 per cent of farms showed signs of loss of soil structure. The survey is carried out intermittently and may be repeated in the future (Nelson et al. 2004). Additional survey data from research and development corporations and grower groups may be available.

The results show that the majority of farmers surveyed by ABARE had a loss of soil structure which impacted negatively on business. A similarly high proportion of surveyed farmers changed their farming practices in response to a loss of soil structure.

References

ABARE (2002) 2001-02 Resource Management Survey: Data Package 2001-02. Australian Bureau of Agricultural and Resource Economics, Canberra. Website- http://www.abareconomics.com/ame/lrm2/lrmalt.asp. Accessed 14/05/2007.

NLWRA (2001) Australian Natural Resources Atlas: Australian Agriculture Assessment 2001 - Appendix 2. Australian Soil Resources Information System: Total phosphorus. National Land amp& Water Resources Audit, Canberra. Website- http://www.anra.gov.au/topics/agriculture/pubs/national/agriculture_asris.html. Accessed 16/07/2008.

Nelson, R., Alexander, F., Elliston, L. and Blias, A. (2004) 2001-02 Resource Management Survey:Natural Resource Management on Australian Farms report. Australian Bureau of Agricultural and Resource Economics, Canberra. Website - http://abareonlineshop.com/PdfFiles/PC12675.pdf. Accessed 14/05/2007.