Environmental Engineering Reference
In-Depth Information
Economic viability of the slash-and-burn and slash-and-no-burn
management systems
A simplified financial analysis carried out by Boa-Amponsem (2002) shows the
profitability of slash-and-burn and slash-and-no-burn management systems on
farmers' field at Nkawie. The land-use type was annual cropping with a field type of
monocrop maize. The mulching material was a mixture of
Chromolaena odorata
and
Panicum maximum
. The data were based on yields of the 2000 minor season.
The partial budget indicated net returns in cedis of 2,010,000 (US$268) and
2,625,000 (US$350) for slash-and-burn and slash-and-no-burn respectively. The lat-
ter practice therefore increased net returns by 23 per cent.
State of the art in the practice of
proka
Proka
as practised today has undergone variable changes in its salient features. In
its original form fire was only used to aid the felling of selected big trees during
land preparation.
Currently, slash-and-burn is used to initiate the practice of
proka
. The
underpinning factor for this shift is a response to the present high cost
and scarcity of farm labour for land clearing, management of the large
amounts of biomass, planting, and the subsequent maintenance of the fields.
The introduction of light-demanding crops, particularly maize, as an intercrop
in agroforest and orchard land-use stages is also a contributory factor. This is
a food security strategy to increase grain stocks of the household and optimize
the use of the land. Zero tillage introduced in areas where the vegetation is thick
is often initiated by the slash-and-burn practice. The subsequent regrowth of
herbaceous plants becomes more amenable to the practice of zero tillage.
Conclusions and recommendations
The study has demonstrated that
proka
as a land management practice conserves
biodiversity and enhances soil biota. It enhances soil fertility through nutrient
recycling and reduction of erosion and runoff. These attributes, together with
enhanced soil moisture conservation and soil physical properties, contribute
significantly to sustained soil productivity and crop yields.
In spite of these benefits,
proka
is increasingly dying off. There is therefore
an urgent need to revive and encourage the use of the
proka
system in order to
attain the goal of biodiversity conservation, sustainable soil and crop productivity,
and environmental quality enhancement. Improvements in
proka
can be achieved
by introducing soil amendments, especially manure and other sources of organic
fertilizers, into the system. Further improvements can be achieved through the
promotion of integrated nutrient management.
