Chin J Plant Ecol ›› 2013, Vol. 37 ›› Issue (3): 209-219.DOI: 10.3724/SP.J.1258.2013.00021

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Allocation patterns of above- and belowground biomass in desert grassland in the middle reaches of Heihe River, Gansu Province, China

WANG Min, SU Yong-Zhong*(), YANG Rong, YANG Xiao   

  1. Linze Inland River Basin Comprehensive Research Station, Chinese Ecosystem Research Network, Cold and Arid Regions Environmental and Engineering Research Institute, Chinese Academy of Sciences, Lanzhou 730000, China
  • Published:2014-02-12
  • Contact: SU Yong-Zhong

Abstract:

Aims The allocation of above- and belowground biomass is highly meaningful in research of carbon storage and cycling in ecosystems. Our objective is to characterize biomass allocation patterns of desert grassland in the middle reaches of Heihe River, Gansu Province, China by providing a detailed study of allocation of above- and belowground biomass.

Methods We used the quadrat survey method to study above- and belowground biomass of desert grassland in July-August, 2011. The allometric relationship between above- and belowground biomass was fitted by the method of reduced major axis (RMA) regression. The vertical distribution pattern of belowground biomass was simulated by the root vertical distribution model developed by Gale and Grigal in 1987.

Important findings Above- and belowground biomass at the community level ranged from 3.2 to 559.2 g·m-2and 3.3 to 188.2 g·m-2, respectively. Above- and belowground biomass of individuals varied from 6.1 to 489.0 g and 2.4 to 244.2 g, respectively. The ratios of root to shoot (R/S) at community and individual levels were 0.10 to 2.49 and 0.07 to 1.55, respectively. Therefore, the aboveground biomass was greater than belowground biomass at both levels, and the R/S ratio was higher at the community level. The slopes of the fitted equations at the community and individual levels were 1.1001 and 0.9913, respectively. Neither was significantly different from 1, which means the allocation patterns between above- and belowground biomass were similar at both levels and indicates an isometric allocation relationship between above- and belowground biomass. Belowground biomass was concentrated mainly in the 0-20 and 0-30 cm soil layers. Root biomass in the 0-20 cm soil depth accounted for 89.81% and 81.42% of the total root biomass at the community and individual levels, respectively. Parallel values for the 0-30 cm soil depth were 96.95% and 93.62%.

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Key words: biomass, desert grassland, isometric relationship, ratio of root to shoot, vertical distribution of belowground biomass