Chemistry Reference
In-Depth Information
food to meet household food requirements.
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The ensuing pursuit for
household food security has, on the other hand, tended to encourage adoption
of practices that degrade soils. Generally, soil degradation gradually
diminishes the capacity of individual farmers and communities to raise
sufficient incomes from farming activities which, in turn, results in the inability
to undertake critical investments needed to conserve the soil and preserve
biodiversity. It also diminishes opportunities for such households to satisfy
their nutritional needs. At the same time, the households become vulnerable to
external shocks and often disinvest in critical productive assets to cope with
such shocks.
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Thus, degradation of natural resources including land (and soil
biodiversity) has the effect of entrenching nutritional and asset poverty, which
in turn reinforce natural resource degradation, thus creating a vicious circle.
This nexus between worsening poverty and degradation of natural resources
raises fundamental questions of the best strategies for managing soil
biodiversity in the tropics. These challenges are highest in many developing
regions, representing the intersection of hot-spots of widespread poverty and
fragile ecosystems (e.g. arid and semi-arid areas, highland regions).
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Governments, donors and development partners in many developing countries
have devoted substantial resources to developing and promoting a diverse mix of
sustainable soil conservation practices. The technologies promoted in this mix
have included indigenous and introduced structural technologies and agronomic
practices, usually aimed at enhancing soil productivity. Some of the structural
methods include soil and stone bunding and terracing, while the agronomic
practices include minimum tillage, organic and inorganic fertilisers, pesticides,
grass strips, and agro-forestry techniques. In addition, a number of agro-forestry
technologies, in particular alley cropping, have been promoted mainly because of
their ability enhance soil organic matter and, in cases involving leguminous
plants, replenish soil nitrogen through nitrogen fixation.
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Despite the increasing efforts made and the growing policy interest, there has
been limited focus on the promotion of soil biodiversity, especially below-ground
biodiversity, in the tropics. Instead, farm households have increased the use of
soil fertility management and agronomic practices that are usually promoted to
enhance agricultural productivity but tend to hurt the below-ground micro- and
macro-organisms. This section first reviews the soil conservation approaches
pursued in the past followed by a discussion of socioeconomic (e.g. incentives and
capacity) and institutional (including market access and policy) and information-
related factors that condition the adoption of sustainable soil conservation
practices likely to affect the biodiversity of tropical soils.
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7.1 Approaches to Soil Conservation: A Historical Perspective
In order to stimulate widespread adoption and adaptation of soil conservation
practices in tropical agriculture, especially in marginal and vulnerable
environments, three major approaches have been used,
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namely, top-down
interventions, populist or farmer-first, and neo-liberal approaches. The early soil
