Environmental Engineering Reference
In-Depth Information
brown or red. Besides direct observation the farmers use the feel method by
rubbing the sand in their palms.
The farmers have a basic knowledge about which types of crops are suitable for
a particular soil. This knowledge is acquired through observation and information
passed on from oral tradition. For example, the
afowiaah
(local name), which
is whitish, is suitable for vegetables, cassava, maize, and plantain, and the gravelly
soils are suitable for cassava. The valley bottoms soils, locally known as
wora
,
are good for dry-season vegetables.
Indicator plants
The use of indicator plants is very common among farmers in determining soil
fertility. For instance, areas dominated by
Chromolaena odorata
(especially where
there is no undergrowth) and elephant grass (where they are bunchy) have good soil
fertility. On the other hand the presence of spear grass (
Imperata
and
Paniacum
rotboelia
) indicates poor fertility. The farmers are also aware of certain tree species,
the presence of which improves the soil fertility and crop yields, e.g.
onyina
-
Ceiba pentandra
. These types of trees are left standing on the farm during land
clearing. However, because of land degradation some of these cannot be found in
the demonstration sites (Buabeng, 1998). Table 3.2 shows some of the indicator
plants.
Micro-fauna, wildlife, and vegetative cover
The third method of assessment is the use of micro-fauna. The presence of
worm casts and worm borings indicates that the soil is fertile. The presence
of wildlife, both arboreal and terrestrial animals, indicates good soil fertility. The
fourth method is the use of vegetative cover. There is no doubt about primary
forest soil fertility.
Table 3.2 Indicator plants
Trees
Local name
Biological name
Yankyere
Ficus varifolia
Funtum
Funtumia elastica
Onyina
Ceiba pentandra
Duma
Ficus capensis
Grasses
Acheampong
Chromolaena odorata
Other grasses
Imperata
Herbs
Nsansono
(itching plant)
Ananse Ntromuhoma
