Land Use Change Detection and Impact Assessment on an Agricultural Area

  •  Beatrice Tarimo    
  •  Elifuraha Mtalo    
  •  Evaristo Liwa    


This study focuses on detecting, mapping and analyzing the conversion of forests into agricultural uses and agricultural uses into urban/peri-urban uses in Nzega district, Tabora Region - Tanzania over a period of 28 years since 1978. Land use classes were from multitemporal and multi-sensor satellite images and aerial photographs. Topographical maps at a scale of 1:50000 and onsite information gathered in the field were used for interpretation and ground truthing purposes. Land use changes were detected using land use change matrices and land use change maps. Four land use maps were compiled from Aerial photographs dated 1978, Landsat TM satellite imagery dated 1986, Landsat ETM+ satellite imagery dated 2000 and IRS satellite imagery dated 2006. The maps show agricultural areas are concentrated along road networks generally expanding towards neighboring grasslands and unprotected forested areas. Land use changes were detected from land use maps for three change periods: 1978 - 1986, 1986 - 2000 and 2000 - 2006, with emphasis on agricultural and forest land uses. The change maps and change matrices show that despite abandoned farms agricultural land increases with time. Change in the opposite direction was also common where abandoned agricultural land gradually regenerated back to grasslands and forests. An average of 16% of agricultural land has been maintained during the 1978 - 2006 period compared to 67% of forests that have been maintained in the same period of time.

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