Nutrient Enrichment Mediates the Relationships of Soil Microbial Respiration with Climatic Factors in an Alpine Meadow

Figure 1

Seasonal variations (A, B, and C) and monthly mean values (a, b, and c) of soil microbial respiration during the 2010, 2011, and 2012 growing seasons. Bars sharing the same letters indicate no significant difference at P < 0.05 significant level. LN, HN, LN + P, and HN + P represent low N (5 g N m⁻² yr⁻¹), high N (10 g N m⁻² yr⁻¹), low N combined with P ((5 g N + 5 g P) m⁻² yr⁻¹), and high N combined with P ((10 g N + 5 g P) m⁻² yr⁻¹), respectively, and in the control treatment (CK) neither N nor P was added.