<p>Hummock-hollow microtopography is a common feature in northern peatlands. It<br>creates microsites of variable hydrology, vegetation, and soil biogeochemistry, thus affect soil C<br>cycling in peatlands at the local scale. This study investigated effects of microtopography on soil<br>enzyme (&#946;-1,4-glucosidase (&#946;G), &#946;-1,4-N-acetylglucosaminidase (NAG), acid phosphatase (AP)<br>and peroxidase (PER)) activities and environment variables as well as their relationships in a<br>typical sedge peatland in Changbai Mountain, northeast of China. Our results showed that the<br>enzyme activities in the sedge peatland significantly varied across seasons and microtopographical<br>positions. Soil enzyme activities in hummocks exhibited more obvious seasonal variation than<br>hollows, with the &#946;G, AP and PER activities presented a distinct valley in summer and the<br>maximum values occurred in Spring or Autumn. Soil hydrolase (&#946;G, NAG and AP) activities in<br>hummocks were significantly higher compared to hollows, while soil oxidase (PER enzyme)<br>activity in hollows was higher than hummocks. The NMDS analysis revealed that the influence<br>degree of microtopography on the enzyme activities was higher than that of seasonal variation.<br>Redundancy analysis (RDA) indicated that the variations of soil enzyme activities in the peatland<br>were related to environmental variables, especially to water table depth (WTD), soil temperature<br>(ST), SOC, N availability and P availability. Furthermore, correlation analysis showed that the<br>three hydrolase (BG, NAG and AP) activities were positively correlated with soil TN, SOC and<br>C/N, and negatively correlated with WTD and TP. On the contrast, the PER activities were<br>positively correlated with TP, and negatively correlated with ST, SOC and C/N. The present<br>study demonstrated that small scale topographic heterogeneity created by hummock cause habitat<br>heterogeneity and thus lead to significant difference of soil enzyme activity between hummock<br>and hollow in the sedge peatlands. This finding provides further evidence of the importance of<br>peatland microtopography to C cycling and has direct implications for scaling biogeochemical<br>processes to the ecosystem level.</p>
Seasonal variation of soil enzyme activities in relation to nutrient and carbon cycling in Senna alata (L.) Roxb invaded sites of Puducherry region, India
