Land use change effect on carbon stocks in western Uganda

This study was conducted in Fortportal Municipality, Kabarole District of Western Uganda to find out the effect of land use change on carbon stocks between 1973 and 2000. Landsat series of 1973, 1986 and 2000 of Fortportal municipality were used to asses land use cover change over the years. The soils and land use maps were overlaid to identify homogeneous units of land use under each of the different soil types. Major homogeneous units included; small scale farm, built up area, grassland, woodland and large-scale farms. 50 m x 50 m plots were randomly selected from which tree species were counted, identified and their diameter above breast height (dbh) measured. The plant carbon stocks were estimated according to Majaliwa et al. (2009). Composite soil samples were collected using a soil auger and analyzed from the laboratory for carbon stock content according to Okalebo et al. (2002). Results indicated that small scale farming covered the largest area of the municipality followed by built up area which was found to be increasing exponentially especially from 8.51% to 28.82% between 1986 and 2000. The study further revealed that carbon stocks were land use dependant in the municipality with about 75% more carbon stocks in soil than in plants. Soil type did not have any effect on the quantity of carbon contained by the soil. A steady decline in carbon stocks was observed over the years. Total soil carbon density was highest (185 mg/ha) in woodland followed by grasslands (115 mg/ha). In conclusion carbon stock (soil and above ground) has been reducing over the last 27 years (1973 - 2000).