Land is the most valuable resource for production of food, fiber, fuel and many other vital goods required to meet human and animal needs. However, it is facing serious threats of deterioration due to inexorable human pressure and utilization incompatible with its capacity. Land degradation is considered one of the most severe global problems worldwide. According to Bai et al., (2008) land degradation is increasing in severity and extent in many parts of the world, with more than 20% of all cultivated areas, 30% of forests and 10% of grasslands undergoing degradation. Land degradation in general, indicates temporary or permanent decline from a higher to a lower status of productivity through deterioration of physical, chemical and biological aspects. From the ecological perspective, land degradation is realized as damage to the healthy functioning of land-based ecosystems (El Baroudy, 2011). Liberti et al., (2009) stated that land degradation phenomena occur by a complex interaction between natural (e.g., soil properties and climate conditions) and human factors (e.g., over-grazing, overcultivation and deforestation). The main types of land degradation issues recognized in the Adea woreda include: salinity, loss of vegetation cover, over exploitation, irrigation, sodicity, compaction and water logging as well as water erosion which can be attributed to Koka dam.
Millions of hectares of land per year are being degraded in all climatic regions in the world (Yagi et al. 2015). In agriculture-based countries with a dependence on subsistence systems, the priority is to increase productivity to achieve food security (FAO, 2010). The decline in land quality caused by human activities has been a major global issue since the 20th century and will remain high on the international agenda in the 21st century (Eswaran et al., 2001). The accessibility of accurate and timely information on nature, extent and spatial distribution of land resources enables and rationalizes the decision-making processes of planners, policy makers and managers in a cost-effective and time efficient manner.
Land degradation can be examined in different ways, such as direct field observation and using remote sensing technology. In comparison to field methods, the remote sensing technique is more cost-effective and time-efficient in which a vast land area can be monitored using one image. A large number of researches have been carried out using different methods of remote sensing and geographic information system (GIS) to determine land degradation risk. Remotely sensed imagery is suitable for revealing land that has been affected by degradation to various levels (Gao and Liu, 2008). Furthermore, remotely sensed data are effective in identifying and mapping land degradation risks and modeling soil loss (Chafer, 2008; Geerken and Ilawi, 2004; Lu et al., 2007; Mathieu et al., 2007). GIS and remote sensing-based studies of land use /land cover change and land degradation analysis can be undertaken at different spatial scales to gives both qualitative (e.g., vulnerable areas) and quantitative information (e.g., soil loss rates). These research paper tries to examine the importance of GIS and remote sensing were employed to asses land use/land cover change and its environmental degradations for the preparation and implementations of sustainable land use management in the Adea woreda.
The aims of this study are temporal and spatial analyses of land degradation by using GIS and remote sensing to show dynamics in degraded land areas of Adea woreda between 2000 and 2022 in relation to land use/land cover change to counter land degradation. The specific objectives of this study were: (1) estimate the average annual soil loss of the woreda; (2) assess the risk of land degradation level depending on remote sensing and GIS techniques; (3) develop comprehensive and appropriate land degradation indicators.