The influence of selected cropping systems on soil properties in Kwalel Village, Lushoto, Tanzania
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Date
2001
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Publisher
Sokoine Univesity of Agriculture
Abstract
A study was conducted in Kwalei village. Lushoto district to evaluate the influence of
selected cropping systems on soil properties. The following cropping systems were
identified through a transect walk, cropping systems on the slopes (monoculture tea.
coffee/banana and maize/beans intercropping systems) and vegetable cropping systems in
valley bottoms. Other cropping systems were woodlot systems (Eucalyptus. Grevillea.
Wattle in a mixture of tree species) and fallows. Three soil profiles representing summits.
slope and footslope areas were dug. According to World Resource Base (WR.B) (FAO.
1998) classification system three soil levels were identified namely Lixisols (summit).
Fluvisols (slope) and Lixisols (footslope). The corresponding USDA-soil classification at
soil order levels were Alfisols (summits). Entisols (slopes) and Mollisols (footslopes).
Soil samples were taken at a depth of 0-20 cm from each identified cropping system for
physical and chemical analysis. Core samples from the same cropping systems were taken
for bulk density determination. The results from cropping systems on the slopes showed
that soils from monoculture tea had low levels of plant nutrients compared to
coffee/banana and maize/beans cropping systems. However, the soil physical properties in
all three cropping systems on the slopes were suitable for crop production. Soil pH was
conducive for tea production. The DTPA extractable Fe was significantly higher (P=0.05)
in monoculture tea than in other cropping systems and the opposite was true for DTPA
extractable Mn. DTPA extractable Zn did not differ significantly (P=0.05) between theiii
cropping systems while DTPA extractable Cu was higher in coffee/banana cropping
system. Most of the plant nutrients in soils from vegetable growing area were adequate for
vegetable production except for available P. DTPA extractable Fe and Zn were within the
acceptable range while DTPA extractable Cu and Mn were above the critical level for
vegetable production. Soil properties in four woodlot systems were variable. Except for
Eucalyptus, other tree species showed superiority in one or more properties. Eucalyptus
had the least effect on soil properties, which suggest that the tree have low potential for
amelioration of soil fertility compared to other tree species. From the study it can be
concluded that fallow systems did not improve the soil fertility of degraded soils in
Kwalei village. This is possibly due to the young age of the fallow systems. It takes long
time to restore soil fertility. It can be recommended from this study that, for optimum crop
production, farmers should control soil erosion, use cover crops and organic fertilisers like
composts, crop residues and farm yard manures.
Description
Dissertation
Keywords
Cropping, Lushoto, Tanzania, FORESTRY, AGRICULTURAL SCIENCES and LANDSCAPE PLANNING::Soil science, Systems, Kwalei village, Lushoto district