Short-term simulated nitrogen deposition increases carbon sequestration in a Pleioblastus amarus plantation

Abstract

In order to understand the influence of nitrogen (N) deposition on the key processes relevant to the carbon (C) balance in a bamboo plantation, a twoyear field experiment involving the simulated deposition of N in a Pleioblastus amarus plantation was conducted in the rainy region of SW China. Four levels of N treatments: control (no N added), low-N (50 kg N ha −1 year −1 ), medium-N (150 kg N ha −1 year −1 ), and high-N (300 kg N ha −1 year −1 ) were set in the present study. The results showed that soil respiration followed a clear seasonal pattern, with the maximum rates in mid-summer and the minimum in late winter. The annual cumulative soil respiration was 585±43 g CO 2 -C m −2 year −1 in the control plots. Simulated N deposition significantly increased the mean annual soil respiration rate, fine root biomass, soil microbial biomass C (MBC), and N concentration in fine roots and fresh leaf litter. Soil respirations exhibited a positive exponential relationship with soil temperature, and a linear relationship with MBC. The net primary production (NPP) ranged from 10.95 to 15.01 Mg C ha −1 year −1 and was higher than the annual soil respiration (5.85 to 7.62 Mg C ha −1 year −1 ) in all treatments. Simulated N deposition increased the net ecosystem production (NEP), and there was a significant difference between the control and high N treatment NEP, whereas, the difference of NEP among control, low-N, and medium-N was not significant. Results suggest that N controlled the primary production in this bamboo plantation ecosystem. Simulated N deposition increased the C sequestration of the P. amarus plantation ecosystem through increasing the plant C pool, though CO 2 emission through soil respiration was also enhanced.

Effects of nitrogen deposition on carbon cycle in terrestrial ecosystems of China: A meta-analysis

“…That is, the old-growth subtropical forests and forests dominated by N-fixing species (tree age > 30 years) (Zhang et al, 2012) were grouped into N-rich ecosystems as they have high soil N concentrations and plant growth in these ecosystems is not limited by N availability (Lu et al, 2010). Early successional forests (Mo et al, 2007;Tu et al, 2010), temperate forests and grasslands, were grouped into N-limited ecosystem because they have low soil N level and plant growth in these ecosystems is limited by N availability. N addition levels were classified into three classes, including low N (LN; 60 kg N ha À1 yr À1 ), medium N (MN; 61e120 kg N ha À1 yr À1 ), and high N (HN; > 120 kg N ha À1 yr À1 ).…”

“…Hence the degree of N deposition and its potential effects on the C cycle in Chinese terrestrial ecosystems should be different and are of increasing global concern due to the increasing interest in regional aspects of the global C cycle (Piao et al, 2009). Several N deposition monitoring programs and increased N deposition simulation experiments have been conducted since the late 1990s (Mo et al, 2006;Niu et al, 2010;Tu et al, 2010;Xu et al, 2009). Liu et al (2011) recently presented a description of the effects of N deposition on ecosystem C cycling in China.…”

Variation of Q10values in a fenced and a grazed grassland on the loess plateau, northwestern China

“…For increasing the accuracy, all data in both fenced and grazed grassland (from three subplots) were parameterized into one regression equation. Then, in each sampling day, we only got one Q 10 value for both fenced and grazed grassland, and the standard error (SE) of apparent Q 10 values were computed by the method of Tu et al (2011). We averaged SR and MR from the 12 collars in each subplot, and the means were used to represent each subplot for analysis.…”

Effects of Nitrogen Deposition on CH4 Uptake and CO2 Emission from a temperate forests in Northeastern China

“…Wang et al (2014) [38] showed that the root biomass of C. angustifoliawas significantly enhanced by N deposition and the increased apportioning of biomass to root was of major significance. Plant respiration rates would increase with increasing tissue N and root biomass under N addition [39]. Therefore, elevated N deposition may result in higher C loss by increasing both autotrophic and heterotrophic respiration.…”