Assessment of the land use changes due to traditional irrigation activities: the case study of four villages around Ruaha Mbuyuni, Iringa and Morogoro Tanzania
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Date
2002
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Publisher
Sokoine University of Agriculture
Abstract
The study on assessment of land use changes due to traditional irrigation activities was
conducted in four villages around Ruaha Mbuyuni from June 2000 to June 2001. Three
sets of aerial photographs (1955, 1976 and 1999) were used, interpreted on mirror
stereoscope and analysed using GIS-ARC/INFO program. The area of each class was'
calculated for each data set from which the rate of expansion of irrigated farms was
determined. The questionnaire survey was conducted to collect information on the
historical changes in natural resources and socio-economic activities responsible for land
use changes and analysed using SPSS program. Stratified random sampling was also
conducted for soil physical and chemical analyses. By using rating procedures the
contribution of soil properties in land use changes was carried out. The results showed
that irrigated fields expanded by 2056.8ha and 1528.6ha with expansion rate of
97.94ha/yr and 66.46ha/yr from 1955 to 1976 and 1976 to 1999 respectively. Human
population increased from 2886 to 16877people between 1967 and 1998. Irrigation
activities have been observed to increase the extent of socio-economic activities like
firewood gathering and building. The results for soil analysis indicated that, total
nitrogen, available phosphorus and organic matter content was low in all fields and
therefore low soil fertility in the area. Exchangeable Na were observed to be high in
some fields and having high potential to cause soil salinity and sodicity. Other chemical
properties i.e pH values, Ca, Mg and CEC were observed to be within the acceptable
range for irrigation activities and crop productivity. The soil physical properties
indicated that the bulk density of the soil were within the acceptable range for water
infiltration and plant roots penetration. The soil textural class was observed to range
from sand loam to sand clay loam for the topsoil and sand to clay for the subsoil.
Generally, the results have shown that the pattern of land use changes in the study area
were due to irrigation activities taking place in the area which has influenced population
growth and socio-economic development.
Description
Dissertation
Keywords
Traditional irrigation, Artificial land resources, Land resources, Soil fertility degradation