Environmental Engineering Reference
In-Depth Information
cropping, grazing, wood harvesting, settlements, and the sheer numbers of people
(Gyasi
et al
., 1995; Gyasi and Uitto, 1997).
Activities
In Ghana, work in the demonstration sites progressed systematically from the
initial focus on understanding baseline agro-ecological conditions and on estab-
lishing social contacts, through the following stages:
•
assessment of biodiversity and agrodiversity
•
identification of traditional, indigenous, or local systems of managing and con-
serving biodiversity, especially in an agricultural context
•
conservation promotion
•
promotion of economic activities that motivate farmers to conserve.
All these are towards the general PLEC quest for models of conserving
biodiversity.
Outputs include essentially traditional farm management practices that
conserve biodiversity (Table 5.1). Among them is traditional agroforestry,
which involves cropping among trees left
in situ
in farms (Plate 1). This has the
advantages of:
•
conserving trees while producing a diversity of food and other crops
•
regenerating soil fertility through nitrogen fixed by some of the plants and by
the substantial biomass they generate.
Another example, as discussed in some detail in Chapters 11 and 14, is the
no-burn farming that avoids use of fire for clearing vegetation, and which
involves mulching by leaving slashed vegetation to decompose, in the practice
called
oprowka
or
proka
by Akan-speaking people (Plate 2). It maintains soil
fertility by conserving and stimulating microbial activity and by humus addi-
tion from decomposing vegetation. Propagation of plants, including farm seeds
in the soil, is promoted by this method.
Through associations of PLEC farmers, which involve expert farmers, these
and other management practices form a basis of PLEC experiments and
demonstrations in biodiversity conservation (Table 5.2). Foremost among the
experiments is one designed to determine the scientific basis of the popular
claim by farmers that certain trees combine effectively with food crops, while
others do not (Owusu-Bennoah and Enu-Kwesi, 2000; see also Chapters 13
and 14). Another is the demonstration of how income may be generated from,
or value added to, conserved resources through the use of home gardens,
fallow areas, and forest maintained in the backyard for keeping bees for
honey and wax (Plate 3; see Chapters 12 and 17). Beekeeping has caught on
the most in Sekesua-Osonson, where it involves approximately 70 house-
holds (Gyasi and Nartey, 2003). A further example of a value-added activity is
