On the technical and scientific levels, first of all, a radical change is needed in the way soils are viewed (and hence, managed) by many agriculturists, scientists and the human society in general. Soil is not a lifeless agglomeration of mineral particles with ions that can be used by plants, rather it is a living entity, and the home of countless organisms whose diversity may even surpass that of those living above-ground, outside the soil. Traditionally, soil has been viewed as a substrate for plants, and in fact, this may be the most important role of soil for human society. However, much more than a factory for plant production, soil is an extremely biodiverse entity; the place of endless reactions that control a large host of services of use to humanity and to the natural environment.
The "Green Revolution", so called because of the large increases in plant production that were obtained by using its techniques, relied on overcoming soil constraints through the application of external inputs such as inorganic fertilizers, and other amendments, in order to meet plant requirements (Sanchez, 1994; 1997). These practices, still under use in a large part of the world’s surface, primarily in developed nations, have greatly benefited humankind, being responsible for important increases in per-capita food production worldwide. However, the vast majority of the world´s farmers do not have access to or can afford the external inputs (agro-chemicals, improved crop varieties, hybrid seeds, ready access to cash and credit), required to apply the principles and practices of high external input agriculture (HEIA) (Vandermeer et al., 1998). Furthermore, the misuse or overuse of practices associated with HEIA have been associated with soil and environmental degradation (i.e. depletion or loss of soil fertility and its physical and biological components, contamination of surface and ground water) and declines in productivity in certain areas of the world (Shiva, 1991).
What is needed therefore is the development and implementation of an integrated soil management approach to agriculture of an integrated approach to agriculture that considers the potential impacts of agriculture on the environment and optimizes the ecological interactions and synergies between biological components of the ecosystem and the biological efficiency of soil processes in order to maintain soil fertility, productivity and crop protection (Altieri, 1995; Woomer and Swift, 1994; Lavelle, 2000).
The challenge of this approach is to show that not only gains in agricultural productivity can be made by optimising biological processes, including the manipulation of soil biota, but also that biological management of soil fertility can be integrated profitably into the rest of the farming enterprise (Swift, 1999) and can simultaneously serve to conserve biologically important populations and species.
This approach can be used in modern commercial agriculture, but has been considered especially useful in marginal lands prior to degradation (i.e. by preventing damage), in degraded lands in need of reclamation and in regions where the availability, access to or use of external inputs is limited (thus leading to a predominance of biological processes in the maintenance of soil fertility) (Anderson, 1994; Sanchez, 1997, Swift, 1999; Senapati et al., 1999).
At technical and policy levels, the challenges to be overcome have to do mostly with demonstrating that the long-term social, economic and conservation benefits of an integrated biological management of soil outweigh the short-term costs (if any), so that specifically designed policies that promote integrated soil biological management can be created and implemented at different hierarchical levels.
back to effect of human activity on biodiversity
