Climate warming continuously increases air and soil temperatures, which in turn will have an important impact on the N-reservoir changes and N-element conversion rates of terrestrial ecosystems by increasing soil microbial activity. On the one hand, it is possible to increase the effectiveness of inorganic nitrogen in the soil and increase plant productivity; On the other hand, it will increase the leaching loss of N and the loss of gases such as N2O, resulting in negative ecological and environmental effects. In situ warming is considered to be an effective means to better simulate the impact of climate warming on the N cycle of terrestrial ecosystems, but the warming schemes (warming devices and timing) used by different researchers, the types of ecosystems of concern and the N cycle process are not consistent.

 

In order to fully understand the possible effects of climate warming on the N cycle, and compare the effects of different warming schemes and the differences in different ecosystem responses, the research team led by Researcher Bai'e of our firm conducted a meta-analysis of the relevant data of more than 50 literatures, showing that the net mineralization rate and net nitrification rate of the soil increased by an average of 52.2% and 32.2% respectively without considering the warming scheme and the difference in ecosystem type. This leads to different degrees of increase in the content of inorganic N and total N in the soil; The effect of warming on soil microbial N changes is small, possibly due to limitations in soil carbon supply. Different ecosystems respond differently to warming treatment, and shrub forests and deserts are less sensitive than forests, possibly because warming is more likely to cause soil water loss in the former two, thereby limiting the conversion rate of their microorganisms to N elements; The effect of different heating devices and heating time is also different, of which the use of heating cables (buried in the soil) and all-weather heating effects are the most obvious. The results of this study are important for a deeper understanding of the response processes of the N cycle to climate warming, as well as the mechanisms by which temperature rises affect plant and ecosystem functions.

 

The research was supported by the National 973 and the Natural Science Foundation project. The findings were published in the international journal New Phytologist ( http://onlinelibrary.wiley.com/doi/10.1111/nph.12252/abstract)