358 Ecological Restoration and Design
1 Processes Contributing to Sustainability
As stated above and discussed below, second-paradigm approaches are not neces-
sarily ‘organic’ in that they do not reject the use of inorganic inputs. Rather, there
is a positive emphasis on mobilizing and managing biological processes so as to
minimize the need for inorganic inputs. Yields as high or higher than those from
first-paradigm practices can be attained through second-paradigm approaches,
contradicting the often-assumed superiority of ‘modern agricultural practices’.
How sustainable alternative agricultural systems will be, and how their long-term
productivity can be enhanced, are both important questions, not currently answer-
able.
As relatively little investment has been made in researching the alternatives to
date, these questions remain to be addressed explicitly and thoroughly. Evaluations
made will be more illuminating if they are undertaken not just in terms of certain
hypotheses to be tested, but are linked to broader questions of how to understand
soil systems and their sustainable productivity. On the basis of both research and
experience, optimizing patterns and rationale for resource use should be developed
and also changed over time as knowledge and feedback from practice accumulate.
It is difficult to sum up in single numbers the changes in soil systems’ fertility
and capabilities as these include contingent qualities such as resilience when con-
fronted with biotic or abiotic stresses. Of particular importance for sustainable
agriculture is the enhancement of soil water-holding capacity and drainage. This is
very dependent on the kinds of soil biological activity that lead to better particle
aggregation, creating soil that can be both better aerated and infused with water at
the same time. The ability of soil systems to absorb rain run-off – to capture what
Savenije (1998) has characterized as ‘green water’, i.e. water stored and used in situ
- will become more and more essential in this century as variability in the timing
and amount of precipitation is likely to become more extreme, which has dreadful
effects on most agriculture. Acquiring and distributing ‘blue water’ from surface
flows or groundwater reserves with all of its costs and inefficiencies in conveyance
will become ever more costly. By contrast, improving soil characteristics through
biological activity and management will store water, the most essential resource for
agriculture, in soil horizons and root zones where it is most needed, and at lower
cost.
The practices presented and evaluated in this book are recent enough that no
conclusions can be firmly drawn about their sustainability. But the biological proc-
esses and effects that are being intensified or enhanced are ones that have been
occurring for ages. The results of sustaining mutually productive associations
between flora and fauna – specific and diverse microbial populations in the rhizo-
sphere and in plant roots themselves – have been the production of growth-pro-
moting hormones, beneficial meso- and macrofauna activity in the soil, biological
nitrogen fixation and phosphorus solubilization, the build-up of carbon in the soil,
mycorrhizal ‘infection’ of roots, induced systemic resistance of plants to damage by
pathogens, diversified root systems in the soil that can access a larger proportion of