title: Effects of precipitation increase on soil respiration: a three-year field experiment in subtropical forests in China.
abstract: BACKGROUND
  The aim of this study was to determine response patterns and mechanisms of soil respiration to precipitation increases in subtropical regions.
  
  
  RESULTS
  Field plots in three typical forests [i.e. pine forest (PF), broadleaf forest (BF), and pine and broadleaf mixed forest (MF)] in subtropical China were exposed under either Double Precipitation (DP) treatment or Ambient Precipitation (AP). Soil respiration, soil temperature, soil moisture, soil microbial biomass and fine root biomass were measured over three years. We tested whether precipitation treatments influenced the relationship of soil respiration rate (R) with soil temperature (T) and soil moisture (M) using R = (a+cM)exp(bT), where a is a parameter related to basal soil respiration; b and c are parameters related to the soil temperature and moisture sensitivities of soil respiration, respectively. We found that the DP treatment only slightly increased mean annual soil respiration in the PF (15.4%) and did not significantly change soil respiration in the MF and the BF. In the BF, the increase in soil respiration was related to the enhancements of both soil fine root biomass and microbial biomass. The DP treatment did not change model parameters, but increased soil moisture, resulting in a slight increase in soil respiration. In the MF and the BF, the DP treatment decreased soil temperature sensitivity b but increased basal soil respiration a, resulting in no significant change in soil respiration.
  
  
  CONCLUSIONS
  Our results indicate that precipitation increasing in subtropical regions in China may have limited effects on soil respiration.
authors: South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, China.
authors: Qi
authors: Q
authors: Deng
authors: Dafeng
authors: D
authors: Hui
authors: Deqiang
authors: D
authors: Zhang
authors: Guoyi
authors: G
authors: Zhou
authors: Juxiu
authors: J
authors: Liu
authors: Shizhong
authors: S
authors: Liu
authors: Guowei
authors: G
authors: Chu
authors: Jiong
authors: J
authors: Li
mesh_terms: D018533:Biomass; D057486:Carbon Cycle; D002245:Carbon Dioxide / Q000378:metabolism*; D002681:China; D018517:Plant Roots / Q000254:growth & development / Q000378:metabolism; D011891:Rain; D012987:Soil; D012988:Soil Microbiology; D013696:Temperature; D014197:Trees / Q000254:growth & development / Q000378:metabolism*; D014329:Tropical Climate
chemical_list: D012987:Soil; D002245:Carbon Dioxide