Determination of evaluation indicators for artificial cultivation of moss biological soil crusts aiming at enhancing soil erosion resistance.

The restoration of moss crust (moss-dominated biological soil crust) through artificial cultivation is of great significance for preventing soil wind erosion and desertification in arid and semi-arid regions. However, the tiny size of moss plant and associated observational challenge hindered the establishment of scientifically validated and standardized indicators for assessing the growth and development of artificial moss crusts. We measured moss crust development indicators, including plant density, coverage, and height every five days during a 60-day cultivation experiment, as well as the dry weight and thickness of moss crust after the cultivation. We determined the eva-luation indicators for the artificial cultivation of moss crusts by analyzing the relationship between those indicators and the stability (characterization of erosion resistance) of moss crusts. The results showed that the new gametophytes germinated after five days cultivation. Plant individual density and coverage of moss crust increased rapidly and turned stable after 35 to 40 days of cultivation. The moss height remained within a narrow range of 1.53 to 1.63 mm during the cultivation. Dry weight of moss and thickness of moss crusts reached 0.0074 g·cm^-2 and 6.30 mm at the end of cultivation, respectively. Moss density exhibited the highest sensitivity to cultivation time, followed by coverage, whereas plant height showed relatively low sensitivity. The stability index of moss crusts cultivated for 60 days ranged from 0.12 to 0.69, which were positively related with plant density and coverage. The comprehensive scoring for development indicators, including moss density, coverage, plant height, biomass, and thickness of moss crusts indicated that moss plant density and coverage are key indicators for assessing the growth and development of artificial moss crusts cultivation.