关键词: 藻结皮, 苔藓, 生物量, 雨滴动能, 水蚀风蚀交错区

Abstract: Based on the field investigation and by the method of simulated single-drop rain, this paper studied the responses of different types of biological soil crusts (biocrusts) in the wind-water erosion interleaving region of Loess Plateau to and their relief effect on the kinetic energy of raindrops. The responses of the biocrusts to raindrop kinetic energy had close relations with their biological composition. The cyanobacteria-dominated biocrusts with a thickness of 1 cm and the moss- dominated biocrusts with the coverage of 80% could resist in 0.99 J and 75.56 J of cumulative rain drop kinetic energy, respectively, and
 the potential resistance of the biocrusts with the same biological compositions was relative to the biomass of the biological compositions, i.e., the larger the biomass, the higher the resistance. As the chlorophyll a content of cyanobacteria- dominated biocrusts (which characterizes the cyanobacterial biomass) increased from 3.32 to 3.73 μg·g^-1, the resistance of the biocrusts against the cumulative raindrop kinetic energy increased from 0.99 to 2.17 J; when the moss biomass in the moss- dominated biocrusts increased from 2.03 to 4.73 g·dm^-2, the resistance of the crusts increased from 6.08 to 75.56 J. During the succession of the biocrusts, their responses to the raindrop kinetic energy presented an “S” pattern. No significant differences in the resistance against raindrop cumulative kinetic energy were observed between the cyanobacteria-dominated biocrusts with variable biomass, but the resistance of moss-dominated biocrusts increased significantly as their biomass per unit area increased. The resistance of moss-dominated biocrusts increased linearly when their biomass increased from 2.03 g·dm^-2 to 4.73 g·dm^-2. The moss-dominated biocrusts could resist in 62.03 J of raindrop kinetic energy when their biomass was up to 3.70 g·dm^-2. Biocrusts had obvious effects in relieving raindrop kinetic energy, and the relief effect increased with their increasing biomass.

Key words: cyanobacteria, moss, biomass, raindrop kinetic energy, wind-water erosion interleaving region