The asymptotic response of soil water holding capacity along restoration duration of artificial grasslands from degraded alpine meadows in the Three River Sources, Qinghai–Tibetan Plateau, China

The artificial grassland is one of the most important practices to restore degraded alpine meadow. However, it is still not clear how the water conservation capacity respond along the restoration duration. We conducted the experiment for soil water holding capacity along the restoration duration of 0 year (extremely degradation, CK), 2 years (2Y), 4 years (4Y), 6 years (6Y) and 12 years (12Y), as well as light degradation (CK₁). Along the restoration duration, aboveground biomass, soil porosity, soil organic carbon, and total nitrogen increased while soil bulk density decreased. The saturated soil water holding capacity increased and plateaued at 6Y restoration duration. The total porosity and soil bulk density played a predominated role in the soil water-holding capacity variations. Our results revealed that the asymptotic response of soil water-holding capacity to restoration duration in artificial grasslands and indicated that 6-year restoration would be appropriate in rehabilitating water conservation for extremely degraded alpine meadow.