Forestry Ecological Engineering in Coastal Saline–Alkali Soils

Abstract

There are about 27 million ha of saline–alkali land in China, including 0.06 million ha of cultivated land and 0.21 million ha of saline–alkali wasteland, mainly distributed in the northeast, north China, northwest inland areas and the coastal areas north of the Yangtze River. Affected by many factors, the area of secondary salinized soil at home and abroad is still expanding. The main ways to prevent salinization are to reduce the groundwater level, improve soil physicochemical properties, and reduce evaporation. According to this principle, selecting suitable tree species and plants and carrying out ecological restoration through vegetation construction is an effective way to improve the use of saline–alkali land . The principle of ecological restoration is to fully understand the formation mechanism, hazard characteristics, and distribution pattern of saline–alkali land , to construct and restore vegetation according to the principle of restoration ecology, and to reduce soil salinity and improve soil by plant adsorption of salt ions, so that the soil structure and farmland ecological environment are enhanced and help to achieve sustainable and efficient use of saline–alkali land . The main technical measures for the ecological restoration of saline–alkali land include water conservancy engineering improvement, biological improvement, agricultural improvement, chemical improvement, and so on. The improvement of water conservancy projects needs to establish and improve the irrigation and drainage engineering system, formulate measures to improve salinization state, and adopt reasonable irrigation techniques; biological improvement is to plant trees in saline–alkaline soil, plant green manure grass and salt-tolerant crops, and reduce surface water evaporation so as to improve physical and chemical properties of the soil; agricultural improvement is to optimize land use , appropriate deep tillage, increase to apply organic fertilizer and perform grass grain rotation, and so on, to reduce soil salinity and prevent soil salinization ; chemical improvement mainly uses chemical amendments to improve saline–alkali land and reduce soil alkali content and increase land production potential.