Differences in soil carbon storage due to mowing, burning and uncontrolled management practices of a grassland at the foot of Mount Sanbe, Japan


Seiji Shimoda, National Agricultural Research Center for Western Region, 6-12-1 Nishifukatsu, Fukuyama, Hiroshima 721-8514, Japan.
Email: sss@affrc.go.jp


To investigate how grassland management practices influence soil carbon pools, we compared soil carbon, its stable isotopic composition (δ13C) and plant root mass among three management areas (17 years of mowing, 17 years of burning, and 10 years of no control) in a secondary grassland at the foot of Mount Sanbe (35°07′N, 132°36′E). The influence of the management practices on soil carbon was limited to the top 5 cm, namely, soil carbon content and δ13C in this layer were higher in the mowed area (5.3 kg C m–2 and −16.4‰) compared to the burned (4.4 kg C m–2 and −17.7‰) and uncontrolled (4.3 kg C m–2 and −18.0‰) areas. Root biomass below 5-cm depth was significantly lower in the mowed area (266 g m–2) than in the burned and uncontrolled areas (1135 and 967 g m–2). The results indicate that management practices for less than 20 years have little effects on soil carbon in deep layers (<5 cm), though deeper distribution of roots in the burned and uncontrolled areas has a potential to supply carbon in the future.