Stoichiometric responses of soil microflora to nutrient additions for two temperate forest soils.

Zhou, Zhenghu; Wang, Chuankuan; Jin, Ying

The ratios of soil carbon (C) to nitrogen (N) and C to phosphorus (P) are much higher in Chinese temperate forest soils than in other forest soils, implying that N and P might limit microbial growth and activities. The objective of this study was to assess stoichiometric responses of microbial biomass, enzyme activities, and respiration to N and P additions. We conducted a nutrient (N, P, and N P) addition experiment in two temperate soils under Korean pine ( Pinus koraiensis) plantation and natural broadleaf forest in Northeast China and measured the microbial biomass C, N, P; the activities of β-glucosidase (BG), N-acetyl- β-glucosaminidase (NAG), and acid and alkaline phosphomonoesterase (AP); and the microbial respiration in the two soils. Nitrogen addition increased microbial biomass N and decreased microbial biomass C-to-N ratio and microbial respiration in the two soils. Nitrogen addition decreased NAG activity to microbial biomass N ratio, P addition decreased AP activity to microbial biomass P ratio, and N, P, and N P additions all increased BG activity to microbial biomass C ratio. These results suggest that microbial stoichiometry is not strictly homeostatic in response to nutrient additions, especially for N addition. The responses of enzyme activities to nutrient additions support the resource allocation theory. The N addition induced a decline in microbial respiration, implying that atmospheric N deposition may reduce microbial respiration, and consequently increase soil C sequestration in the temperate region.

PINUS koraiensis; STOICHIOMETRIC combustion; PLANT nutrients; FOREST soils; MICROBIAL growth

Biology & Fertility of Soils, 2017, Vol 53, Issue 4, p397

0178-2762

Academic Journal

10.1007/s00374-017-1188-y