Landscape Design as a Tool to Reduce Soil Salinization: The Study Case of Keriya Oasis (NW China)

摘要

Irrational use and management of water and land are associated with poor hydro-geological conditions causing water logging and salinization problems, possibly leading to farmland abandonment and economic loss. This poses a great challenge to the sustainability of oasis’ and requires desalinization through reasonable landscape design by multiple crossing studies so we collected traditional knowledge by field interviews and literature schemes, except for the modern desalinization approaches by literature, and we found that the salinization problem has been solved by traditional land reclamation, traditional drainage, natural drainage and flood irrigation, locally. It is worth mentioning that the traditional reclamation in salinized areas requires flood water, sand dunes and a salinized pit area; the sand dunes are used to elevate the pit surface, and water is used to leach salt from the soil. Natural drainage (the depth and width are 4−10 m and 50−100 m, respectively) caused by flash flooding has significant benefits to some salinized villages in the range of 3000−5000 m and ancient groundwater drainage systems, such as Karez are supporting the oasis with drainage water for centuries. In addition landscape characteristics, salinization and hydro-geological conditions of the oasis were studied from Landsat image, DEM, literature and field photos. Then based on the gathered information above, a desalinization model was developed to decrease the groundwater table and salt leaching in the water logging landscape. Then according to landscape characteristics, different desalinization approaches were recommended for different landscapes. To address environmental uncertainties, an adaptive landscape management and refinement approach was developed, and acceptance of the model was validated by stakeholder opinion. The results provide guidelines for sustainable desalinization design and highlight the importance of combining traditional knowledge and modern ecological principles in sustainable landscape design.