Spatial Heterogeneity Of Soil Methane Production On The Micro-scale In Reed Marsh In The Minjiang River Estuary

The Minjiang River estuary wetland is one of the most representative and typical estuarine wetlands in the southeast China. Reed (Phragmites australis) is an important native species in the Min River estuary. The spatial heterogeneity of soil methane production potential were investigated on1.6m2scale, as well as the role of contents of methane production substrates and electronic receptors as the relavant factors, in the reed marsh in the Min River estuary. The results showed that, the range of methane production potential were between0.002μg·g-1·d-1and4.268μg·g-1·d-1, the average methane production potential was0.465μg·g-1·d-1. Methane production potential in the0-5cm soil layer was maximum, the second high value occurred in the layer of25-30cm, they were significant differeces from other soil layers. The methane production potential variability of different soil layers and profiles were large, the coefficients of variation were more than100%. Spatial distribution characteristics of different layers and profiles were very different. The substrates of methane produces (carbon dioxide, acetic acid, DOC), the impact factors (NH4+, NO3-, SO42-) and so on, which spatial variability were also higher. As a whole, the impact factors had no significant correlation with methane production potential; the spatial variation of salinity and pH value were relatively small, and methane produced have no significant correlation with above factors; The proportion of soil particle of less than2μm had a significant relationship with the methane production potential.