It is critical to gain insight into the responses of forest soils to the changing climate. We simulated future climate conditions with growing season throughfall reduction (by 50%) and winter snow removal using a paired-plot design across a soil drainage class gradient at three upland, Populus-dominated forests in northern Minnesota, USA. In situ bulk soil respiration and concentrations of extractable soil N were measured during the summers of 2020–2021. Soil respiration and N concentrations were not affected by throughfall reduction and snow removal, which was largely attributed to the limited treatment effects on soil moisture content and soil temperature. Drainage class was only a significant factor during the spring thaw period in 2021. During this period, the poorly drained plots had lower respiration rates compared to the well-drained plots, which was associated with the drainage class effects on soil temperature. The results of the companion laboratory incubation with varying levels of soil moisture also indicated no effect of the treatment on soil respiration, but effects of drainage class and moisture content on respiration were observed. Our results indicate that the combined effects of reduced summer and winter precipitation on soil respiration and N dynamics may be limited across the range of conditions that occurred in our study.
Bibliographical noteFunding Information:
The authors thank everyone who helped with snow removal at the sites: Alexis Grinde, Steve Kolbe, Stephen Nelson, and Ryan Steiner (UMD Natural Resources Research Institute) and Anne Gapinski and Gwen Keller (UMN). We thank Nathan Aspelin (chemistry laboratory analyst) and the USDA Forest Service Northern Research Station for leading the soil chemical analyses; Rodney Venterea and Scott Mitchell at the USDA Agricultural Research Service for help with the incubation and running the gas chromatograph analyses; Tyler Roman (USDA Forest Service Northern Research Station) for help with the calibration of the LICOR LI-8100; and Jacob Burdick at the Marcell Research Center for lodging (USDA Forest Service Northern Research Station). Participation of all Forest Service personnel was funded by the Northern Research Station and Pacific Northwest Research Station of the USDA Forest Service. We also thank Hannah Friesen for the assistance with the snow removal and statistical analyses/code.
Funding for this project was provided by the Minnesota Environment and Natural Resources Trust Fund as recommended by the Legislative-Citizen Commission on Minnesota Resources (LCCMR).
© 2022 by the authors.
- forest soils
- nitrogen dynamics
- snow removal
- soil respiration
- throughfall reduction