Relation of fine root distribution to soil C in a Cunninghamia lanceolata plantation in subtropical China

Abstract

Growth and distribution of fine roots closely depend on soil resource availability and affect soil C distribution in return. Understanding of relationships between fine root distribution and soil C can help to predict the contribution of fine root turnover to soil C accumulation. A study was conducted in a subtropical Cunninghamia lanceolata plantation to assess the fine root mass density (FRMD), fine root C density (FRCD) of different fine root groups as well as their relations with soil C. The FRMD and FRCD of short-lived roots, dead roots and herb roots peaked in the 0–10 cm soil layer and decreased with soil depth, while FRMD, FRCD of long-lived roots peaked in the 10–20 cm soil layer. Soil C was positively related to FRMD and FRCD of total fine roots (across all three soil layers), dead roots (0–10 cm) and herb roots (10–20 cm) as well as FRCD of short-lived roots (20–40 cm) (P <0.05). Soil C was mainly affected by herb roots in upper soil layers and by woody plant roots in deeper soil layers.