Standardisation of soil quality attributes

An understanding of the nature of soils in natural and human influence ecosystems is essential if progress is to be made in the determination and monitoring of soil quality. This paper briefly discuss the changing circumstances which have resulted in the increased awareness of the importance of soil as a key component of both natural and human influenced environmental systems. These changed circumstances and the recognition of the often crucial role that soils play within these systems has resulted in a demand for measures of soil quality, similar to those used in the characterisation of water and air. Whilst it is relatively straightforward to quantify the fitness to breathe of air, or the fitness to drink with respect to water, it is considerably more difficult to identify similar criteria to be applied to soil. In part this arises because of the wide range of uses to which soils are put and in part because of the complexity of the soil system and the possibility that changes in the soil may be slow and possibly only occur when some threshold is reached. The paper stresses that any index of soil quality must consider soil function, and these functions are varied and often complex. A soil which is considered to be of high quality for one function may not be so for other functions. As a consequence there are potentially many soil properties which might serve as indicators of soil quality, and research is required to identify the most suitable. It may also be questioned whether it is appropriate to pursue this notion of a limited number of soil quality indicators. If an indicator is chosen comparisons between sites and results from different investigators are not possible unless the methods of analysis are given. Standard methods of soil analysis must be developed. These standard methods are distinct from national standard values, or indicator values frequently set by national governments or regulatory agencies. The International Standardisation Organisation (ISO) has developed a programme for the development of standard methods of soil analysis across a range of possible properties including visible, biological, physical and chemical properties. If it is decided that soil quality indicators are required and progress is to be made on developing acceptable indicators of soil quality with agreed standard methods of determination there is need for co-operation amongst soil scientists and those involved in determining appropriate and sustainable use of the soil. © 2002 Elsevier Science B.V. All rights reserved.