CO<sub>2</sub> enrichment increases nutrient leaching from model forest ecosystems in subtropical China

Abstract

Abstract. The effect of high atmospheric CO 2 concentrations on the dynamics of mineral nutrient is not well documented, especially for subtropical China. We used model forest ecosystems in open-top chambers to study the effects of CO 2 enrichment alone and together with N addition on the dynamics of soil cations and anions. Two years of exposure to a 700 ppm CO 2 atmospheric concentration resulted in increased annual nutrient losses by leaching below 70 cm soil profile. Compared to the control, net Mg 2+ losses increased by 385%, K + by 223%, Ca 2+ by 167% and NO − 3 -N by 108%, respectively. Increased losses following exposure to elevated CO 2 were related to both faster weathering of minerals/organic matter decomposition and greater amounts of leaching water. Net annual nutrient losses in the high CO 2 concentration chambers reached 22.2 kg ha −1 year −1 for K + , 171.3 kg ha −1 year −1 for Ca 2+ , 8.2 kg ha −1 year −1 for Mg 2+ and about 2 kg ha −1 year −1 for NO − 3 -N. The N addition alone had no significant effect on the mineral nutrient leaching losses. However, addition of N together with the high CO 2 treatment significantly reduced mineral nutrient losses.We hypothesize that forests in subtropical China might suffer from nutrient limitation and reduction in plant biomass under elevated CO 2 concentration due to mineral leaching losses in the future.

Responses of soil respiration to elevated carbon dioxide and nitrogen addition in young subtropical forest ecosystems in China

“…1). The seasonality of soil temperature and moisture was consistent with the seasonal patterns of air temperature and precipitation (Liu et al, 2008). Annual mean soil temperature and soil moisture were 21.25 ± 0.19 • C and 20.42 ± 0.90%, respectively in the CK chambers.…”

“…Total annual solar radiation reaches 4.37-4.60 GJ m −2 yr −1 in the photosynthetic active radiation (PAR) range. The mean annual temperature is 21.5 • C, and the mean relative humidity is 77% (Liu et al, 2008).…”

“…Simultaneously, the soil was collected as three different layers (0-20, 20-40 and 40-70 cm depth) that were homogenised separately and used to fill the below-ground part of the chambers. The lateritic soil with its chemical properties (before the soil was collected) was shown in Liu et al (2008 …”

Effects of Precipitation Increase on Soil Respiration: A Three-Year Field Experiment in Subtropical Forests in China

“…aFrom Liu et al (2007) [57].bUnpublished data from the Dinghushan Forest Ecosystem Research Station (2007–2009).cFrom Zhang et al (2006) [33]. SOM and LAI represent soil organic matter in the top 10 cm depth and leaf area index, respectively.…”

Effect of CO2 Enrichment on Synthesis of Some Primary and Secondary Metabolites in Ginger (Zingiber officinale Roscoe)

“…Such a reduction of stomatal conductance and diffusion may result in reduced vapor losses per unit of CO 2 assimilated [8] and usually translates into decreased rates of plant transpiration per unit leaf area and increased soil moisture in CO 2 -enriched conditions [9]. As carbon dioxide level doubled, stomatal conductance was shown to reduce by 30–40%, however there were variations among species [10]. Concomitant to this, water use efficiency (WUE) will also increase.…”