Soil fissures help in the restoration of vegetation on secondary bare alkali-saline soil patches on the Songnen Plain, China

Excerpt

Fissures are a natural phenomenon of clay soils caused by shrinkage during dry or freezing conditions (Tian et al. 2003a; Vogel et al. 2005). The size and number of fissures is influenced by soil water content, temperature, clay content, and salinity (Lima and Grismer 1992; Tang et al. 2010). Fissures increase the rate of evaporation of soil moisture, can damage plant roots, and can trap seeds, resulting in local accumulations of seeds in the seed bank (Burmeier et al. 2010; Tian et al. 2003b). Some research concentrates on disadvantage of soil fissures, such as the destruction of grass roots (Tian et al. 2003a). However, fissures also act as natural seed traps that have significant positive implications for the restoration of secondary bare alkali-saline soil patches (Burmeier et al. 2010; Elberling 2000).

Songnen Plain is located in northeastern China (Hu et al. 2009). It is dominated by Chinese lyme grass (Leymus chinensis) and is one of the most grazed and mown grasslands in China (Zheng and Li 1993). The plain is surrounded by mountains and has very poor drainage, which contributes to the high clay and soil salinity content (Zheng and Li 1999). The plain also has many bare alkali-saline patches…