Xiao, CW; Sang, WeiGuo; Wang, RenZ
Fine root dynamics and turnover rate were studied by
sequential soil coring method in a 60-year-old Asia white birch (Betula platyphylla) forest of
Donglingshan Mountain, China. Biomass and necromass of both the finest (<1 mm) and very fine (1-2
mm) roots in 0-55 cm soil layer were determined every month from April to October 2006. The ratio
of necromass to biomass, production, mortality, disappearance and turnover rate of both the
finest and very fine roots in 0-55 cm soil layer were estimated. Some dynamics of biomass and
production of both the finest and very fine roots were explained by meteorological conditions.
Biomass, necromass, ratio of necromass to biomass, production, mortality and disappearance of
both the finest and very fine roots greatly varied during the growing season. Biomass and
production of both the finest and very fine roots decreased from May to June, probably due to the
greater carbon investment in the aboveground parts of the trees in the period. Production of both
the finest and very fine roots, and precipitation and air temperature were the highest in July,
suggesting that the precipitation and air temperature in July are very propitious to root growth
of Asia white birch and the plant has a highest potential for water and nutrient uptake in the
period. Biomass, necromass, production, mortality, disappearance and turnover rate of the finest
roots were significantly higher than those of very fine roots, whereas the ratio of necromass to
biomass of the finest roots was significantly lower than that of very fine roots. Fine root mass,
production, mortality, disappearance and turnover rate decreased, but ratio of necromass to
biomass increased along soil depth for both the finest and very fine roots. The mean turnover
rate of the finest roots, very fine roots and fine roots of the two size classes in the 0-55 cm
soil layer were 0.63, 0.39 and 0.51 year(-1), respectively. (C) 2007 Elsevier B.V. All rights
reserved.