Land use change has a significant impact on the ecosystem. In this paper the effects of land use change on the physicochemical properties of the soil in Rulindo District, Rwanda have been studied. Three different land use types were selected; forestland, cattle farmland and cultivated land. A randomised complete block research design was used to carry out this research. Nine soil samples were collected and then analysed. The distributed samples were analysed in the Soil Laboratory of University of Rwanda-Busogo campus, while the undisturbed samples were analysed in-situ. Eight physicochemical properties were measured: pH, Organic Matter (OM), available nitrogen, available phosphorus, exchangeable potassium, soil bulk density, moisture content and porosity. The results showed that changing land use from forest or farm to cultivated land reduced the organic matter, available nitrogen, soil moisture and porosity while bulk density and pH were significantly increasing. On the other hand, the exchangeable potassium and exchangeable phosphorus did not change significantly for the both land use changes. Hence, the reduction of forestland and farmland are highly sensible to erosion and will decline soil fertility. The paper proposed few steps and recommendations to be the base for a new sustainable land use management in Rwanda.

The failing ecosystem services in Thika-Chania catchment is manifested in the deterioration of water quality, sedimentation of reservoirs, and subsequent increase in water treatment costs due to high turbidity. The services can be restored by implementing relevant soil and water conservation practices to enhance flow regulation and control sediment yield. The impacts of contour farming and filter strips on water and sediment yield were evaluated using Soil Water and Assessment Tool (SWAT), Texas A&M University, USA. Sediment calibration and validation was achieved using data obtained from a bathymetric survey. Model parameters were adjusted to simulate the conservation impacts of contour farming and filter strips. Results indicated the average annual sediment yield as 22 t/ha at the outlet of the catchment and average annual surface runoff of 202 mm. The simulation results showed that filter strips of 5 m width would reduce the average annual sediment yield from the catchment by 54%. The efficacy of filter strips in reducing sediment yield was observed to increase with increasing filter width. Three-meter filter strips and contour farming reduced the average annual sediment yield at catchment outlet by 46% and 36%, respectively. It was concluded that the implementation of contour farming and filters strips reduced sediments by 63% from the base value. Water yield at the sub-basin level was only influenced by contour farming. The total water yield at the catchment outlet experienced no significant change.

Water availability is one of the most important factors for economic development in the Middle East. The Water Evaluation And Planning (WEAP) model was used to assess present and future water demand and supply in Syria till 2050. Nonconventional water resources, climate change, development, industrial growth, regional cooperation, and implementation of new water saving techniques/devices were considered important factors to include in the analysis using the WEAP model. Six scenarios were evaluated depending on the actual situation, climate change, best available technology, advanced technology, regional cooperation, and regional conflict. The results display a vital need for new water resources to balance the unmet water demands. Climate change will have a major effect on Syrian water resources; possible regional conflict will also to a major extent affect water balance. However, regional cooperation and using the best available technology can help in minimizing the gap between supply and demand.