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Quantify the loss of major ions induced by CO 2 enrichment and nitrogen addition in subtropical model forest ecosystems
Author(s) -
Liu Juxiu,
Zhang Deqiang,
Huang Wenjuan,
Zhou Guoyi,
Li Yuelin,
Liu Shizhong
Publication year - 2014
Publication title -
journal of geophysical research: biogeosciences
Language(s) - English
Resource type - Journals
eISSN - 2169-8961
pISSN - 2169-8953
DOI - 10.1002/2013jg002343
Subject(s) - tropical and subtropical moist broadleaf forests , leaching (pedology) , subtropics , environmental chemistry , chemistry , nitrogen , nutrient , leachate , soil water , temperate climate , metal , temperate forest , environmental science , botany , ecology , soil science , biology , organic chemistry
Previous studies have reported that atmospheric CO 2 enrichment would increase the ion concentrations in the soil water. However, none of these studies could exactly quantify the amount of ion changes in the soil water induced by elevated CO 2 and all of these experiments were carried out only in the temperate areas. Using an open‐top chamber design, we studied the effects of CO 2 enrichment alone and together with nitrogen (N) addition on soil water chemistry in the subtropics. Three years of exposure to an atmospheric CO 2 concentration of 700 ppm resulted in accelerated base cation loss via leaching water below the 70 cm soil profile. The total of base cation (K + + Na + + Ca 2+ + Mg 2+ ) loss in the elevated CO 2 treatment was higher than that of the control by 220%, 115%, and 106% in 2006, 2007, and 2008, respectively. The N treatment decreased the effect of high CO 2 treatment on the base cation loss in the leachates. Compared to the control, N addition induced greater metal cation (Al 3+ and Mn 2+ ) leaching loss in 2008 and net Al 3+ and Mn 2+ loss in the high N treatment increased by 100% and 67%, respectively. However, the CO 2 treatment decreased the effect of high N treatment on the metal cation loss. Changes of ion export followed by the exposure to the elevated CO 2 , and N treatments were related to both ion concentrations and leached water amount. We hypothesize that forests in subtropical China might suffer from nutrient limitation and some poisonous metal activation in plant biomass under future global change.