Temperature sensitivity of soil respiration is affected by nitrogen fertilization and land use

Wetlands are an important component of the terrestrial ecosystem, and play a crucial role in sequestering carbon. However, to date, there is little information about the land-use and nitrogen-fertilization effects on temperature sensitivity of soil respiration in wetland. In this investigation, effects of land use and nitrogen fertilization on temperature sensitivity of soil respiration (Q 10) in a freshwater marsh of northeast China were studied. The results showed that change of land use significantly affected Q 10-value, which followed the order: Intact Deyeuxia angustifolia wetland soil >upland forest soil >abandoned cultivated soil >cultivated soil. Our data confirmed that soil temperature and moisture were important factors affecting Q 10-values. Besides temperature and soil moisture, availability of C and N and microbial activity in soil were important factors affecting Q 10-values. Nitrogen fertilization resulted in an increase in Q 10-value not only in the intact wetland, but also in the cultivated soil. Although availability of N could stimulate temperature sensitivity of soil respiration, high nitrogen fertilization (i.e., 240 kg N ha-1 in this study) inhibited temperature sensitivity. Further studies are indicated as a means of answering these questions and providing additional information on the effects of nitrogen fertilization on Q 10-value.