N2O emissions in tropical rainforest and rubber plantation, the indicator from landuse changing in Xishuangbanna, Southwest China
Abstract
To explore the effects of land use change on N2O emissions and local climate change in the tropics, we observed N2O fluxes from a primary tropical rainforest (TRF, litter remove and control treatment) and a fertilized rubber plantation (RP, fertilizer (75 kg N ha-1 yr-1) and unfertilized treatment) at Xishuangbanna, southwest China from 2012 to 2014. The results have shown:1) Comparing to the unfertilized RP and TRF, which have the similar seasonal dynamic with one peak in the middle of rainy season, fertilizer has significantly modified RP N2O emission dynamics in rubber plantation. 2) Fertilization and litter input changed soil N2O emission dominated factors in RP and TRF respectively: the explain rate of soil temperature and soil moisture to N2O of fertilized RP is higher than that in the unfertilized RP. While in TRF, the main controllers are litter carbon input and soil DOC content in control treatment, are soil temperature and soil NO3—N in litter remove treatment 3) Field and laboratory experiments indicated TRF N2O emission mainly from denitrification, RP N2O mainly from nitrification. 4) Considering the treatments effect, soil N2O emissions (fertilized: 4.0 kg N ha-1 yr-1, unfertilized treatment: 2.5 kg N ha-1 yr-1) in RP is far greater than tropical rainforest (control: 0.48 kg N ha-1 yr-1; litter remove: 0.32 kg N ha-1 yr-1). 5) On a unit area basis, the 100-year carbon dioxide equivalence of the fertilized RP N2O offsets 5.8% and 31.5% of carbon sink of the rubber plantation and local TRF, respectively. When entire land area in Xishuangbanna is considered, N2O emissions from fertilized RP offset 17.1% of the tropical rainforest's carbon sink. The results showed that when tropical rainforests are converted to fertilized rubber plantations, the N2O emission seasonal dynamic and mechanisms changed, N2O flux and global warming content are enhanced, which may local environmental regional N2O emissions may enhance local climate warming.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2018
- Bibcode:
- 2018AGUFM.B21K2489Z
- Keywords:
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- 3322 Land/atmosphere interactions;
- ATMOSPHERIC PROCESSESDE: 0414 Biogeochemical cycles;
- processes;
- and modeling;
- BIOGEOSCIENCESDE: 0469 Nitrogen cycling;
- BIOGEOSCIENCESDE: 0490 Trace gases;
- BIOGEOSCIENCES