title: Restricted mineralization of fresh organic materials incorporated into a subtropical paddy soil.
abstract: BACKGROUND
  Microbial activities involved in the dynamics of organic matter determine the potential for organic carbon (C) accumulation in soil. To understand this for paddy soil, an incubation experiment (25 °C, 45% water-holding capacity) was established using (14)C-labelled glucose and rice straw (500 µg C g(-1) soil) as substrates; an adjacent upland soil was used for comparison.
  
  
  RESULTS
  The amount of microbial biomass in the paddy soil was approximately 6 times larger and its turnover rate was 1.5-3 times faster than in the upland soil. These proportions of (14)C-labelled glucose and rice straw mineralized in the paddy soil were about 3% smaller (P < 0.01) than those in the upland soil. Also, there was no significant priming effect of fresh substrate additions on the mineralization of native organic C in the paddy soil, while the priming effect was significant in the upland soil.
  
  
  CONCLUSIONS
  Although the paddy soil contains a large amount of microbial biomass, which is also very active, the mineralization of fresh substrates is significantly restricted in this soil, along with a small priming effect. This favours the accumulation of organic C in paddy soils.
authors: Key Laboratory of Agro-ecological Processes in the Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha, China. jswu@isa.ac.cn
authors: Jinshui
authors: J
authors: Wu
authors: Ping
authors: P
authors: Zhou
authors: Ling
authors: L
authors: Li
authors: Yirong
authors: Y
authors: Su
authors: Hongzhao
authors: H
authors: Yuan
authors: John Keith
authors: JK
authors: Syers
mesh_terms: D000383:Agriculture; D018533:Biomass; D002244:Carbon / Q000032:analysis* / Q000378:metabolism; D057486:Carbon Cycle; D017753:Ecosystem; D005947:Glucose / Q000378:metabolism; D008903:Minerals; D012275:Oryza / Q000378:metabolism* / Q000382:microbiology; D012987:Soil / Q000737:chemistry*; D012988:Soil Microbiology; D014329:Tropical Climate
chemical_list: D008903:Minerals; D012987:Soil; D002244:Carbon; D005947:Glucose