Date of Publication: February 16, 2023

One-Line Summary: Global warming will make forest soils less fertile 

Who did it: A team of researchers from Austria, Netherlands, and Germany.  

What did they study: They warmed forest soil by +4 ^oC (= +7 ˚F) for 14 years, then measured the amount of phosphorus* in it, then they compared it to forest soil that had not been warmed. 

What they found: The soils that had been warmed contained less phosphorus than the never-warmed soils.

Why does this matter:  When trees can’t get enough phosphorous they either don’t grow or die altogether.  Previous research had shown that the amount of phosphorous in European forest soils has been decreasing for decades, but there’s been controversy about the cause.  This work shows that the cause was likely global warming, and that more global warming is going to make it even worse.

What next: In these experiments, soils were only warmed during the snow-free season, however, winter warming is likely to be greater than in summer. Future experiments to warm the soils year-round could test the effects of reduced snow cover on phosphorus cycling.

Our take:  Planting trees is often proposed as a solution to climate change.  We know that increasing greenhouse gases increase plant growth, particularly in the root zone, underneath the soil.  When a lack of phosphorous slows tree growth, it also reduces the forest’s ability to capture carbon (i.e., draw-down carbon dioxide).

*The basics: Phosphorus is an essential element for life on our planet, as it is found in every molecule of DNA and ATP; plants get their phosphorous from the soil.

Who to talk to: Dr. Ye Tian, University of Vienna, ye.tian@univie.ac.at; Dr. Wolfgang Wanek, University of Vienna, wolfgang.wanek@univie.ac.at

The paper: Tian, Y., Shi, C., Malo, C.U. et al. Long-term soil warming decreases microbial phosphorus utilization by increasing abiotic phosphorus sorption and phosphorus losses. Nature Communications 14, 864 (2023).

Journal page: https://www.nature.com/articles/s41467-023-36527-8

Keywords: soil, phosphorus, global warming, forests, Europe, climate change, plants, trees, fertilizer, wood, plants