Study On Greenhouse Gas （CO₂, CH₄,N₂O） Emission Fluxes In Plantations In Wuliangsuhai Wetland

In this study, static camera obscura-GC technique is used to observe the greenhouse gas fluxes in three plantations (Tamarix chinensis Lour, Populus euphratica Oliv, Elaeagnus angustifolia L.) soil-plant in Wuliangsuhai wetland, which Elaeagnus angustifolia L. is divided into Elaeagnus angustifolia L. A and Elaeagnus angustifolia L. B according to soil moisture. The size of the soil moisture is Tamarix chinensis Lour>Populus euphratica Oliv>Elaeagnus angustifolia L. B> Elaeagnus angustifolia L. A, which the soil moisture of Tamarix chinensis Lour, Populus euphratica Oliv, and Elaeagnus angustifolia L. B are significantly higher than the Elaeagnus angustifolia L.A.The results showed that:(1) The emission of total ecosystem respiration(TER) during the growing season in plantation soil-plant are Tamarix chinensis Lour>Elaeagnus angustifolia L. B> Elaeagnus angustifolia L. A>Populus euphratica Oliv, which the emission of CO2 in Tamarix chinensis Lour, Elaeagnus angustifolia L. B and Elaeagnus angustifolia L. A are significantly higher than the Populus euphratica Oliv’s. TER in all plantations have a significant positive correlation (p<0.01) with the temperature inside and underground 5cm, and has a significant linear correlation (p<0.05) with soil dissolved organic carbon (DOC),which described that temperature and DOC have a significant impact on the TER.(2) The CH4 fluxes in all plantation are positive, which is manifested as a source of CH4.The order of fluxes are Tamarix chinensis Lour>Elaeagnus angustifolia L. B> Elaeagnus angustifolia L. A>Populus euphratica Oliv, which the fluxes in Tamarix chinensis Lour and Elaeagnus angustifolia L. B are significantly higher than the Populus euphratica oliv’s, and there is no significant differences between Elaeagnus angustifolia L. A and Populus euphratica Oliv. The CH4 fluxes in all plantations and soil temperature at 5cm are significantly index correlated (p<0.01), indicating that soil temperature is the main factors that influence CH4 fluxes.(3) The N2O fluxes in plantations also showed as a source. The order of fluxes are Tamarix chinensis Lour> Populus euphratica Oliv>Elaeagnus angustifolia L. B> Elaeagnus angustifolia L. A, which the fluxes in Tamarix chinensis Lour and Populus euphratica Oliv and Elaeagnus angustifolia L. B are significantly higher than the Elaeagnus angustifolia L.A.The N2O fluxes have a significant positive correlation (p<0.05) with soil moisture, which Elaeagnus angustifolia L.B reached extremely significant (p<0.01); The N2O fluxes in Tamarix chinensis Lour and Elaeagnus angustifolia L. B have a significant positive Correlation (p<0.01) with soil nitrate content, and the N2O flux in Populus euphratica Oliv has a significant positive correlation(p <0.05)with soil nitrate content, the N2O flux in Elaeagnus angustifolia L. A have no significant correlation (p>0.05) with soil nitrate content. There are no significant correlation (p> 0.05) between N2O fluxes in Tamarix chinensis Lour, Populus euphratica Oliv and Elaeagnus angustifolia L. B and Soil nitrogen Content, but the N2O flux in Elaeagnus angustifolia L. A and soil nitrogen content showed a significant negative correlation (p<0.05). These results indicate that in Tamarix chinensis Lour, Populus euphratica Oliv and Elaeagnus angustifolia L. B, N2O is produced primarily concerned with microbial denitrification, and in Elaeagnus angustifolia L. A, N2O is produced mainly by nitrification. The Soil moisture Of Tamarix chinensis Lour, Populus euphratica Oliv,and Elaeagnus angustifolia L. B are significantly higher than the Elaeagnus angustifolia L. A also can explain the problem.