Free-Grazing versus Enclosure Lead to an Increase in the Germination of the Leymus chinensis Seed Bank in the Hulunbuir Grassland

Abstract

Leymus chinensis is a primary plant in the meadow steppe and typical steppe of China. With global warming and increasing grazing intensity, grassland degradation is being exacerbated. To better protect the L. chinensis grassland in this area and provide a theoretical basis for restoring it, this paper compared the germinable seed bank in the soil and the germination characteristics of L. chinensis (including initial germination time, duration of germination, germination termination time, germination dynamics, and germination index) in free-grazing and enclosed areas. At the same time, combining information about the density of L. chinensis on the ground and previous research results, a comprehensive analysis was conducted. The major results were: (1) there was no significant difference in the number of germinable seeds in the soil between the free-grazing area and the enclosed area, and these seeds were mainly concentrated in the 0–2 cm soil layer. (2) The free-grazing area resulted in a significant increase in the number of germinable L. chinensis seeds and advanced the initial germination time. (3) The number of soil germinated seeds and the number of L. chinensis germinated seeds decreased with the increase in soil depth. (4) Livestock grazing behaviours increased seed burial, thus improving the L. chinensis germination rate. At the same time, the L. chinensis seed bearing percentage and seed quality and the number of germinable L. chinensis seeds were significantly higher in the free-grazing area than in the enclosed area. However, this result still needs to be further explored.