Abstract
Abstract. Leguminous tree plantations at phosphorus (P) limited sites may result in excess nitrogen (N) and higher rates of nitrous oxide (N2O) emissions. However, the effects of N and P applications on soil N2O emissions from plantations with N-fixing vs. non-N-fixing tree species have rarely been studied in the field. We conducted an experimental manipulation of N and/or P additions in two plantations with Acacia auriculiformis (AA, N-fixing) and Eucalyptus urophylla (EU, non-N-fixing) in South China. The objective was to determine the effects of N or P addition alone, as well as NP application together on soil N2O emissions from these tropical plantations. We found that the average N2O emission from control was greater in the AA (2.3 ± 0.1 kg N2O–N ha−1 yr−1) than in EU plantation (1.9 ± 0.1 kg N2O–N ha−1 yr−1). For the AA plantation, N addition stimulated N2O emission from the soil while P addition did not. Applications of N with P together significantly decreased N2O emission compared to N addition alone, especially in the high-level treatments (decreased by 18%). In the EU plantation, N2O emissions significantly decreased in P-addition plots compared with the controls; however, N and NP additions did not. The different response of N2O emission to N or P addition was attributed to the higher initial soil N status in the AA than that of EU plantation, due to symbiotic N fixation in the former. Our result suggests that atmospheric N deposition potentially stimulates N2O emissions from leguminous tree plantations in the tropics, whereas P fertilization has the potential to mitigate N-deposition-induced N2O emissions from such plantations.
Highlights
Nitrous oxide is a powerful greenhouse gas that is 298 times more potent than carbon dioxide (CO2) over a 100 yr lifespan (IPCC, 2007), and contributes to stratospheric ozone (O3) depletion (Ravishankara et al, 2009)
The responses of soil N2O emissions to nutrient additions were studied in two tropical plantations with N-fixing and non-N-fixing tree species
We found that leguminous tree plantations in the study region may potentially emit more N2O after N addition, due to its high initial soil N availability
Summary
Nitrous oxide is a powerful greenhouse gas that is 298 times more potent than carbon dioxide (CO2) over a 100 yr lifespan (IPCC, 2007), and contributes to stratospheric ozone (O3) depletion (Ravishankara et al, 2009). Atmospheric N2O concentration has been increasing by 0.2–0.3 % yr−1 over the last 250 yr (Stocker et al, 2013). N2O is naturally produced by bacterial metabolism during nitrification and denitrification processes in many environments, soils (Barnard et al, 2005). Tropical forest soils are an important source for N2O emission, accounting for 14 % to 23 % of current global N2O budget (IPCC, 2007). Anthropogenic activities have great impact on the global and regional N cycles, thereby enhancing the mobility of reactive N within ecosystems (Vitousek et al, 1997). Atmospheric N deposition has increased dramatically during recent decades due to intensive agricultural production, fossil fuel combustion, and cultivation of N-fixing plants (Galloway et al, 2008). Worldwide N deposition is projected to increase by 50 % to 100 % in 2030 relative to 2000, with
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
