Managing Soil Quality - Synthesis

Summary

There is an urgent need to analyse the term soil quality in more detail. Most frequently, it is used to describe soil attributes. The term should be used for this purpose only when related to the sustainability concerns (i) soil productivity, (ii) impact on the environment, and (iii) effect on human health. The soil quality concept has been adopted mainly as a technical framework for grading soil and evaluating management effects. We advocate more focus on soil quality as a cognitive concept associated with sustainability. Grading of soils by indicators is difficult across soil types, climates and cropping systems. The indexing of soil quality indicators introduce a significant loss of information on the complex agroecosystem. The contributions to the present book show that it is generally not possible to identify simple thresholds for sustainable farming neither at the soil quality indicator level nor at the management level. More adequate means of communicating management prescriptions to farmers and other decision makers in society are needed. Decisions should be based on knowledge on management effects on individual soil types as well as on stochastic and mechanistic models simulating soil processes and functions. Teams of researchers and stakeholders are needed in a joined effort towards optimal decisions. This calls for well-educated farmers and consultants. Scientific contributions towards sustainable farming should be based on combinations of on-farm system studies and analyses of specific soil functions. The main purpose of on-farm studies is to develop that particular system rather than to compare it with other systems. System studies may enable identification of emergent properties, which are important in system development and in identifying gabs in our understanding of the soil ecosystem. There is an urgent need to communicate scientific results with explicit expressions of sustainability priorities. This is to facilitate transfer of results from agricultural research and to encourage scientists to cope with the precautionary principle, adduced by environmentalists and other concerned citizens.