Environmental Engineering Reference
In-Depth Information
Nyamedua, Astonia boonei
,
agyama, Alcornea cordifolia
, and
osese,
Hollarrhena floribunda
, which, according to farmers, use their long tap-root
system to draw water for plants in their environs, featured prominently in
Amanase and Gyamfiase as trees that combine well with crops (Asante, 2001).
Similarly, a diversity of vegetables like pepper, garden eggs, and okra is culti-
vated as a hedge against risks associated with drought. Attempts at finding the
diversity index for the major staples, notably cassava and yams, were frustrated
by difficulty in classifying them by their different local names, even within the
same locality.
A typical cropping sequence begins by interplanting maize with minor crops
including vegetables. This mixture is later interplanted with cassava and others
such as banana or plantain. After two or three years of cultivation on the same plot,
the plot is left to fallow. Plants normally left on farms as they fallow, and which
are harvested from time to time, include perennials, notably tree crops, vegetables
such as pepper and garden eggs, and annuals such as cassava and yams.
Crop biodiversity provides the ecosystem resilience necessary to cope with
periodic stresses on the environment, such as drought and climate variability
among others. These adaptive strategies bear testimony to the indigenous and
sophisticated adaptation of production systems by farmers to the unique charac-
teristics of their environment.
Planting materials
Farmers also respond to rainfall variability and unpredictability by using seeds
saved from the previous harvest. These are obtained from other farmers at a token
fee, and from the local markets. Agricultural extension shops are the purchasing
points of high-yielding and early-maturing seeds of both cereals and vegetables.
The continuous use of seeds saved from previous harvests ensures maintenance
of local genetic diversity available to farmers, thereby enabling them to manipu-
late production systems to suit local conditions better.
Tastes and preferences of the farmers to a large extent determine what they
grow, and this also conditions their choice of planting materials collected from
colleagues. The rationale for using seeds saved from the previous harvest is that
such seeds are likely to survive any adverse weather during the current planting
time because they survived the previous season. As noted earlier, several new cas-
sava varieties have been introduced into the study area from neighbouring Togo
and Benin. Notable among them are
gbezey
,
agbeli-atsilapka
,
yevuvie
, and
nyonuvie
(all Ewe names), which have been introduced in Gyamfiase and
Amanase where there are a lot of tenant Ayigbe farmers. Through exchange of
visits between demonstration sites and germplasm among farmers, these newly
introduced varieties have diffused to Sekesua.
High-yielding improved maize types such as
obaatanpa
(Twi name) and
abelehie
(Ga-Adangbe name), though a bit late in maturing (between 90 and 110 days),
