Sustainable land use is a complex topic and requires expertise in environmental sciences (including soil and water sciences), atmospheric studies, plant and animal ecology and production, environmental microbiology, economics, sociology and political science. The integration of these sources of knowledge is central to any decisions made about land use.
Why are soil organisms relevant to discussions about land management practices? Current knowledge of soil biology highlights the contribution that soil biological processes make through retaining soil in a state that minimises environmental degradation and sustains long-term productivity of natural and introduced plant species. Therefore, soil organisms and soil biological fertility have the potential to substantially enhance land management practices. Soil biologists are well placed to clarify the biological characteristics of soil. As for physical and chemical measures of soil quality such as nutrient content and pH, some biological measurements will be useful in assessing the status of the soil for sustainable production.
In research on soil quality, soil biologists need to: (i) demonstrate the important role of soil organisms and identify mechanisms of their function and interaction; (ii) explain the links between soil physical, chemical and biological processes; (iii) design and conduct experiments to test hypotheses related to the appropriateness of biological indicators of soil quality; and (iv) collaborate with land managers to integrate knowledge of soil biology into practical strategies for soil management.
The lack of attention to soil biological fertility has not always been characteristic of land management. Past civilisations have been aware of the need to enhance and gain benefit from biological processes in soil, as is evident from emerging interest in application of biochar in soil (Lehmann and Joseph 2009). Sustainability of many agricultural systems will depend more and more on developing and maintaining all components of soil fertility.
The four final topics in this book illustrate how soil organisms are relevant to sustainable land management: (i) Consideration of the potential for using soil organisms or microbial processes as indicators of soil quality. This necessitates a discussion of soil quality that cannot be restricted to biological processes; (ii) Examination of the role of the scientist in the application of knowledge of soil biology in sustainable land use. This includes identification of topics that need further experimentation; (iii) Assessment of the economic implications of addressing issues of soil biological fertility to order to retain long-term viable production, in contrast to short-term production gains that increase land degradation; and (iv) Reflection on principles, guidelines and future possibilities for application of knowledge of soil biological fertility within the framework of sustainable land use.