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Geostatistical estimation of surface soil carbon stock in Mt. Wakakusa grassland of Japan

Kamarudin, Khairun N., Tomita, Mayu, Kondo, Keiko, Abe, Susumu S.
Landscape and ecological engineering 2019 v.15 no.2 pp. 215-221
carbon sequestration, carbon sinks, geostatistics, grassland soils, grasslands, models, organic carbon, soil carbon, uncertainty, Japan
Although nation-wide assessments on the grassland soil carbon storage have been conducted in Japan, the uncertainty of the estimation accuracy remains with its local variability. In the present study, using geostatistical approach, we assessed the spatial variability and distribution pattern of organic carbon (OC) and estimated its total stock in the surface soils (0–5 cm) over Mt. Wakakusa grassland (30.2 ha) of Central Japan. The exploratory statistics indicated that the surface soils had 1.88 ± 0.28 kg C m⁻² of soil OC density on average (n = 147) with a moderate variability (CV = 18.8%), while the geostatistical analysis unveiled that its semivariogram was well fitted by a spherical model (R² = 0.93, RSS = 1.15E⁻⁰⁵) and had a strong spatial dependency (nugget–sill ratio = 0.31). Based on these results, we constructed an interpolated map and estimated total OC stock to 552 Mg C in the surface soil of Mt. Wakakusa grassland.