Fluxes of nitrous oxide and methane in different coastal Suaeda salsa marshes of the Yellow River estuary, China

Song

et al. 2013

Ecological Engineering

a b s t r a c tSalt-affected soils are extensively present and constitute about 7% of total land surface. However, our knowledge about nitrous oxide (N 2 O) production through rapid nitrification and denitrification processes between the atmosphere and the saline soil is very limited. In order to evaluate the potential of N 2 O consumption in saline soils, this study was therefore designed to quantify the variability in N 2 O emissions monthly in the Yellow River Delta in China. Main issues include: different saline-alkaline soils and temporal aspects. Our aim was to quantify N 2 O emissions and identify the major drivers controlling its emissions for providing guidance in eco-restoring coastal wetland on large scale. By using in situ closed chambers the annual average emissions of N 2 O from the mudflat was determined and it was significantly higher than plant communities, especially herbage communities. In general, the emissions of N 2 O of different ecosystems showed a unique-peak annual pattern, with the peak in September. Saline-alkaline mudflat and different vegetations acted as N 2 O source in the Yellow River Delta and the N 2 O emission of different ecosystems followed the order: Saline-alkaline mudflat > T. chinensis >S. salsa > P. australis. Therefore restoration of saline land through revegetation was necessary to reduce the N 2 O emission of saline soils. The effects of air and soil temperature on N 2 O fluxes were significant in salt-affected soils except P. australis. Soil water content and electrical conductivity correlated positively or negatively with N 2 O emissions in mudflat and P. australis community. While relationships between N 2 O production and other soil properties (TC, TN, C:N ratio, NH 4 + -N and NO 3 − -N) were only significant in mudflat and T. chinensis community. Temporal variations of N 2 O emission were related to the interactions of abiotic factors (air and soil temperature, soil water content and electrical conductivity) and the variations of other soil properties, while spatial variations were mainly affected by the vegetation composition at spatial scale.

Section: Discussionmentioning

confidence: 96%

Section: Discussionmentioning

confidence: 99%

Seasonal dynamics in nitrous oxide emissions under different types of vegetation in saline-alkaline soils of the Yellow River Delta, China and implications for eco-restoring coastal wetland

Song

et al. 2013

Ecological Engineering

Forest Ecology and Management

“…riparian ecosystems can oxidize CH 4 as upland grassland and forest ecosystems. This phenomenon has been reported in many studies (Hopfensperger et al, 2009;Sun et al, 2013bSun et al, , 2013c and was also seen at this site in the mature plantation and in the newly planted stand (Figs. 3e and 4b).…”

Section: Magnitude Of F Ch4mentioning

confidence: 57%

Ecosystem carbon (CO2 and CH4) fluxes of a Populus dettoides plantation in subtropical China during and post clear-cutting

Shenghua

Chen

Tang

et al. 2015

a b s t r a c tPoplar plantations have widely spread around the world due to its high productivity and adaptability. Clear-cutting is the primary harvesting method for poplar plantation management in southern China. However, the effect of harvesting on ecosystem carbon fluxes limits our ability to estimate its carbon sequestration. A consecutive, three-year observation on ecosystem CO 2 and CH 4 flux (F CO2 and F CH4 ) of a Populus dettoides plantation on the floodplain of Yangtze River was made prior and post to the clearcutting using an eddy-covariance system. We found that clear-cutting turned the ecosystem from a strong carbon sink to a mediate carbon source only in several months, July to next January, after the harvest. The ecosystem turned to a net carbon sink at the beginning of the first growing season following clear-cutting due to the large productivity of understory vegetation in this region. The annual carbon budget was À424.3 ± 52.5 g-C m À2 (95% confidence interval) in the harvesting year, with À53.6 ± 22.8 g-C m À2 the first year and À290.7 ± 34.2 g-C m À2 the second year after clear-cutting. Clear-cutting turned the ecosystem from a net CH 4 sink to a net CH 4 source after the third month, but during the three years the CH 4 emission only balanced out a very small portion (0.3%) of F CO2 . In noninundation periods, F CH4 varied from À0.01 to 0.24 mmol m À2 d À1 , with a mean (±SD) of 0.11 ± 0.08 mmol m À2 d À1 , while it ranged from 0.33 to 4.39 mmol m À2 d À1 during inundation, with a mean (±SD) of 2.17 ± 1.16 mmol m À2 d À1 . Daily and weekly F CH4 during non-inundation period were highly correlated with ground water table, soil moisture, and friction velocity, while F CH4 during inundation depended on inundation depth.

“…Annual evaporation is 1962 mm and annual precipitation is 551.6 mm, with about 70% of precipitation occurring between June and August. The soils in the study area are dominated by intrazonal tidal soil and salt soil (Mou et al 2011;Sun et al 2013aSun et al , 2013b. The main plant communities include T. chinensis, S. salsa and P. australis.…”

Section: Study Sitementioning

confidence: 99%

“…So the higher salt-tolerance in the naturally occurring saline soils suggests that using the saltadding method with a non-saline soil would underestimate the CH 4 uptake rates in the naturally saline soils (Zhang et al 2011). Sun et al (2013aSun et al ( , 2013b investigated CH 4 and N 2 O fluxes from the coastal marshes in the Yellow River estuary, but our knowledge about GHG turnover between the atmosphere and the saline soils are very limited. In this study, we investigated GHG emissions of naturally saline soils in the Yellow River Delta (YRD).…”

Section: Introductionmentioning

confidence: 99%

Diurnal dynamics of CH₄, CO₂and N₂O fluxes in the saline-alkaline soils of the Yellow River Delta, China

Song

Plant Biosystems - An International Journal Dealing with all As

et al. 2014

Salt-affected soils are extensively present and constitute about 7% of total land surface. However, our knowledge about greenhouse gas (GHG) turnover between the atmosphere and the saline soils is very limited. In order to evaluate the potential of GHG consumption in saline soils, we measured gas fluxes of carbon dioxide (CO 2 ), methane (CH 4 ) and nitrous oxide (N 2 O) from the soil surface to the atmosphere under saline-alkaline mudflat and various community types in the Yellow River Delta in China. In general, the emissions of GHG of different ecosystems showed a unique peak diurnal pattern, with the peak at 13:00 h and the lowest value at 07:00 h. The CH 4 and N 2 O emission of different ecosystems followed the order: saline-alkaline mudflat . T. chinensis . S. salsa . P. australis, while the CO 2 emission followed the order: T. chinensis . P. australis . S. salsa . saline-alkaline mudflat. On the whole, saline-alkaline mudflat and different vegetations acted as CO 2 and N 2 O source in spring, while saline-alkaline mudflat and P. australis communities acted as CH 4 source and CH 4 sink, respectively. However, T. chinensis and S. salsa communities acted as CH 4 sink before 12:00 h and CH 4 source after 12:00 h. Although measurements of the CO 2 , CH 4 and N 2 O fluxes were taken simultaneously, CH 4 and N 2 O fluxes were strongly correlated with soil moisture, temperature and electrical conductivity, while no significant correlation was found between CO 2 flux with above environmental factors. These results probably suggest that factors other than soil temperature, moisture and salinity exerted a larger impact on fluxes than on CH 4 and N 2 O release and/or that there were not enough samples for CO 2 flux measurements because of its higher spatial and temporal variability.