9. Conclusion

Back to: Soil health for Victoria's agriculture - context, terminology and concepts

Soil health is a concern worldwide and affects matters of food security, environmental protection, water quality, and infrastructure. Examples of policies (charters, agreements, memorandi of understanding) and programs for soil health (or, more generally, soil management) exist in the United States, United Kingdom, Canada, New Zealand and the European Union. Principal documents have been cited in this report and can be accessed on the world wide web (section 1.2).

Terminology (section 2) has been explained and should be used consistently in future work, using the definitions here as a basis. Scientific literature on soil health (or soil quality) is substantial and many key sources have been cited in this report. There are also many frameworks that can be used to organise complex components of knowledge associated with soils and some examples of these have also been given. The agro– ecosystem framework for soil health (Figure 2) and the landscape design research framework (Figure 8) are the most important in this respect.

The DPI initiatives in soil health (LWA and ESAS projects) represent a significant contribution to the efforts that are needed to address improvements in soil management in the dryland cropping areas of the Mallee, Wimmera and south–west Victoria. Experience gained in, and evaluation of, these projects should serve to support expansion of soil health activity in other parts of Victoria and for other agricultural industries. Environmental implications of soil health and the wider provision of ecosystem services need to be considered in the development of initiatives that will augment and complement those in agricultural production. This report and, in particular, the summary descriptions of relationships between soil functions and ecosystem services (section 6) should be used to inform the development of the ‘Land Health and Biodiversity’ white paper currently in preparation by DSE.

Empirical research into the interactions between soil and management practices is critically needed in particular with respect to soil functions, soil biology and the agro–ecosystem. Questions are frequently asked about the impact that herbicides, fungicides, nematocides and insecticides may be having on soil biology, and whether these inputs compromise soil health. At this time there is insufficient knowledge of this subject to provide satisfactory answers.

There have been many changes in agricultural management in recent decades, and while these have resulted in very positive soil health outcomes there is still a need to broaden the adoption of practices that protect and improve soil. In particular, reduction in tillage, retention of organic residues and control of traffic play key roles in improving soil structure and hydrological properties as well as maintaining or increasing yields. Adoption of these practices more widely will be supported by better information but there are areas where long–established practices work against these principles. Cultivation to ‘ridge’ soils and protect them from wind erosion and cultivation to control summer weeds are widespread practices in the north west of the state and advocated as best practice by some DPI agronomists. While this may work from an enterprise perspective there are no gains being made in soil improvement through such practices. Data and knowledge management for soils remains a priority but this is being tackled with funding in the Healthy Soils and Datatrack projects.