Chin J Plant Ecol ›› 2014, Vol. 38 ›› Issue (2): 125-133.DOI: 10.3724/SP.J.1258.2014.00011

• Research Articles • Previous Articles     Next Articles

Biomass allocation response of species with different life history strategies to nitrogen and water addition in sandy grassland in Inner Mongolia

MAO Wei1,*(), LI Yu-Lin1, CUI Duo2, ZHAO Xue-Yong1, ZHANG Tong-Hui1, LI Yu-Qiang1   

  1. 1Naiman Desertification Research Station, Cold and Arid Regions Environmental and Engineering Research Institute, Chinese Academy of Sciences, Lanzhou 730000, China
    2Center for Earth System Science, Tsinghua University, Beijing 100084, China
  • Received:2013-01-15 Accepted:2013-04-02 Online:2014-01-15 Published:2014-02-12
  • Contact: MAO Wei


Aims We examine how resources influence plant productivity and plant biomass allocation in dry sandy grasslands. Our specific objective is to determine whether 1) annual species and perennial species differ in biomass allocation in response to nitrogen and water addition and 2) if differentiation exists, how nitrogen- and water-induced changes in biomass allocation for species affect ecosystem functioning at the community scale.
Methods This experiment was established in 2010 in the central region of the Horqin sandy grassland in Inner Mongolia. Two treatments, nitrogen and water addition, were started in May, and we measured leaf traits, leaf biomass, stem biomass, stem:leaf ratio, reproductive biomass and vegetative height of the dominant species.
Important findings Biomass allocation in response to nitrogen and water differed between annual species and perennial species. With nitrogen addition the reproductive biomass of annual species decreased 75.6% and the leaf biomass of annual species increased 86.7%. Water addition did not alter biomass allocation, but the interaction of nitrogen and water did. The relative stem biomass values increased 6.2% with nitrogen addition × increased snow in winter treatment, and relative leaf biomass values increased 15.3%. In nitrogen addition × increased precipitation in summer treatments, relative stem biomass and relative leaf biomass increased 28.7% and 19.4%, respectively. Nitrogen and water addition did not alter the biomass allocation pattern of perennial species, but the interaction of nitrogen and water increased reproductive biomass 40%. Nitrogen addition altered biomass allocation at the community scale. Relative reproduction biomass decreased 39.4%, and relative leaf values increased 40.1% with nitrogen addition treatments. On average, relative stem biomass decreased 23.4% and relative leaf biomass increased 57.1% with water addition. The interaction of nitrogen and water addition also significantly altered biomass allocation. Community reproductive biomass decreased 48.3%, community stem biomass decreased 31% and community leaf biomass increased 57.5% in nitrogen × precipitation treatments. We also found that community plant height increased with added nitrogen or water, resulting in a change of community vertical structure.

Key words: biomass allocation, community structure, functional group, nitrogen addition