Nitrogen Deposition Reduces Phosphorus-Induced Stimulation of Soil Respiration

A new study published in Geoderma, led by Professor Faming Wang at the South China Botanical Garden, reveals how nitrogen deposition and phosphorus input influence soil respiration (R_S) and its components—autotrophic respiration (R_A) and heterotrophic respiration (R_H). 

The research, conducted over eight years in a tropical secondary forest, shows that phosphorus input significantly increased R_S by 19.2% and R_H by 42.1%. However, nitrogen addition reduced these increases, mitigating R_S by 33.2% annually and R_H by 58.3%.

Interestingly, the combined addition of N and P boosted R_A more than either nutrient alone. This suggests that nitrogen deposition primarily reduces the stimulatory effect of phosphorus on soil respiration by limiting R_H rather than R_A.

These findings suggest that prevalent N deposition across low latitudes could have substantially mitigate C emissions from forest soils under anthropogenic P input.

The article link is: https://authors.elsevier.com/sd/article/S0016-7061(24)00371-9

Fig. 1 Effects of N addition, P addition, and the combination of N and P co-additions on temporal variations in soil respiration (Image by WANG et al)

Fig. 2 Structural equation model (SEM) depicted the major pathways of N and P additions affecting soil respiration 

 (Image by WANG et al)