Assessment of environmental degradation in Nakambala Mazabuka Zambia
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Date
1996
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Sokoine University of Agriculture
Abstract
An environmental degradation assessment was carried out in
Nakambala Estate, Mazabuka Zambia in October 1994 to June
1995 .
The objectives of the study were:
impact
change,
of
the
natural
sugar
plantation
vegetation
between 1970 and 1993 ;
(b)
and
(a)
on demographic
resource degradation
expansion
land
to assess the
to assess the soil physical and
chemical status in cultivated and abandoned areas; and (c) to
compare current
soil physical and chemical
status of the
study area with the status when the sugar plantation was
being established.
Sequential aerial photography was used in assessing sugar
plantation expansion and its impact on natural vegetation and
land resource degradation. The impact of the sugar plantation
expansion on demographic changes and energy needs (fuelwood)
was also assessed. A field soil survey was carried out to
assess
soil
condition
in
terms
of
general
fertility
and
selected land qualities and characteristics matched with the
requirements of irrigated sugarcane using the FAO (1983) land
suitability
framework.
Soil
carried out by using indices.
degradation
assessment
wasiii
The results of the study were; the sugar plantation expanded
by 7 035 ha between 1970 and 1991; human population increased
by 4 929 (at 4% per annum) and projected to reach 22 127 by
the year 2 000.
to
sugar
Natural vegetation was reduced by 25 % due
plantation
expansion
aggravating
the
fuelwood
deficit situation (5 447 m3/year in 1970 and 4 906 m3/year in
1991) . There was no visible evidence of soil erosion although
waterlogging was the prevalent form of land degradation in
all the mapping units. The soils are generally eutric (base
saturation > 50%) with slight acidic to neutral reaction in
cultivated fields (in mapping units; 2W,
10,
11 and 12) to
slightly alkaline reaction in areas with abandoned fields
(soil mapping unit 13). High soil bulk densities occur in
soil mapping unit 2W due to compaction by heavy machinery and
due to inherent nature of the soils in mapping units 10, 11,
12 and 13 (heavy clays). Oxygen inavailability (due to poor
drainage), physical degradation and poor rooting conditions
(due to shallow effective soil depth) are the most limiting
conditions
for
sugarcane
changes in chemical status
growing.
Over
time,
noticeable
(sodication) was low in all the
mapping units except in unit 10 where sodication development
was
noticed.
Adverse
soil physical
changes
(crusting and
surface sealing) occurred in soil mapping units 11,
13.
12 andiv
To
stem
environmental
deforestation,
degradation
in
the
form
of
energy utilization from fuelwood should be
reduced by electrifying township housing units. The continued
use
of
vetiva
grass
for drain protection
is advised. Alternative land uses in soil mapping units 11, 12 and 13 and
complete abandonment of monocropping practices in these soils
is strongly recommended.
Description
MSc. Dissertation in Agricultural Engineering
Keywords
Sugar plantation expansion, Land resource degradation, Environmental degradation, Mazabuka-Zambia