Abstract: To clarify the soil stoichiometry characteristics of alpine meadow at its different degradation stages, the native Kobresia meadow, mildly degraded meadow, and seriously degraded sandy meadow were selected to measure their soil organic carbon (SOC), total nitrogen (N),
total phosphorous (P), and total potassium (K) contents at different soil depths. With the degradation of alpine meadow, the SOC, N, P, K, C∶N, C∶P, C∶K, N∶P, N∶K, and P∶K in 0-100 cm profiles presently a decreasing trend, and SOC was most sensitive to the degradation, followed by total N, P, and K. The SOC and N in top (0-20 cm) soil could be used as the most sensitive indicators for the degradation degree of alpine meadow. The vertical distribution of SOC, N, P, and K differed with the degradation stage of the alpine meadow. For native Kobresia meadow and mildly degraded meadow, the SOC, N, P, K, C∶N, C∶P, C∶K, N∶P, N∶K, and P∶K in 0-40 cm soil layer decreased sharply with soil depth, but those in 40-100 cm soil layer had a slow decrease and tended to be stable; for seriously degraded sandy meadow, these stoichiometry characteristics remained unchanged with soil depth.

Key words: PM_2.5, meteorological factor, summer and autumn, prediction, Beijing.