Soil physicochemical dynamics across three alpine meadows differing in the magnitude of grazing pressure: Implications for Ophiocordyceps sinensis (Berk.) G.H. Sung et al.

Abstract

Over-exploitation, and resultant habitat degradation, have often been reported for the declining yield of Yartsa Gunbu (Ophiocordyceps sinensis (Berk.) G H Sung et al.). Does livestock grazing aggravate the situation? Three sites, differing in the magnitude of grazing pressure- Janthri, experiencing no grazing pressure; Balmiya top, with moderate grazing pressure, and Rukhiyan, experiencing relatively greater grazing pressure were selected. The soil parameters studied were the following-soil texture, bulk density, soil moisture, pH, organic carbon content, total organic matter, total and available nitrogen content. Our results indicate that with the increase in grazing pressure, soil moisture content, soil organic carbon, soil organic matter, and available nitrogen decreases. The total nitrogen content exhibits a decline at 0–10 cm soil depth in site experiencing relatively greater grazing pressure, while it remains high in 10–20 and 20–30 cm soil depth in site experiencing light or moderate grazing pressure. Soil bulk density inevitably increases with increasing grazing pressure. An increase in bulk density is negatively correlated with larval population size in all the sites, while the rest of the parameters exhibit a positive correlation ( P < 0.05 ). Of all the parameters studied, it would be safe to conclude that changes in soil bulk density, pH, and moisture are of greater concern as relates to larval population size. The declining population size of the host Thitarodes larva, as brought forth in the present study is a cause of concern for the future availability of Yartsa Gunbu.