Terraced Landscapes: Land Abandonment, Soil Degradation, and Suitable Management

Abstract

Agricultural terraces are among the most visible and extensive human signatures on different landscapes of the world. Terraces are generally built to retain soil and water, to reduce erosion, and to support irrigation. They reduce slope gradient and length, and facilitate the infiltration of water in areas with a moderate to low soil permeability by controlling the overland flow velocity. Thereby, they create positive effects on agricultural activities. Since ancient times, agricultural terraces have been built in different topographic conditions (e.g. coastal area, hilly, and steep slope mountain landscapes) and used for the cultivation of various crops (e.g. vineyards, fruit and olive groves, cereals, tea). Their management however arises relevant critical issues. Historical terraces are often of the bench type with stone walls and require adequate maintenance. Poorly designed and controlled terraces can lead to slope failures, often due to walls collapsing, increasing potential soil water erosion. Also, terraced areas are often served by agricultural roads that can profoundly influence surface hydrologic processes and erosion. Land abandonment and ageing of the local population , which affected several regions of the world during the last decades, are among the main reasons for the poor maintenance of terraced landscapes . As a consequence, a progressive increase of land degradation and loss of soil functions (e.g. food production, environmental interaction such as water storage, filtering and transformation, biological habitat, physical and cultural heritage ) is observed. The purpose of this chapter is to highlight the main critical issues of terraced landscapes , providing a few case studies, and a possible solution for proper long-term management.