title: Interaction effects of elevated CO₂ and temperature on microbial biomass and enzyme activities in tropical rice soils.
abstract: The impacts of elevated CO(2) and temperature on microbial biomass and soil enzyme activities in four physicochemically different types of tropical rice soils (Aeric Endoaquept, Aeric Tropoaquept, Ultic Haplustalf and Udic Rhodostalf) were investigated in a laboratory incubation study. Soil samples were incubated under 400, 500 and 600 μmol mol(-1) CO(2) concentration at 25°C, 35°C and 45°C for 2 months. Elevated CO(2) significantly increased the mean microbial biomass carbon (MBC) content, across the soils, over control by 6.2%, 38.0% and 49.2% at 400, 500 and 600 μmol mol(-1) CO(2) concentration, respectively. Soil enzyme activities (fluorescein diacetate hydrolase, dehydrogenase, β-glucosidase, urease, alkaline and acid phosphatases) also increased significantly ranging from 1.3% (urease) to 53.2% (alkaline phosphatase) under high CO(2) in the soils studied. Both MBC and soil enzyme activities were further stimulated at high temperatures suggesting elevated CO(2) and high temperature interaction accelerated the general turnover of the organic C fractions of the soil and through increase in microbially mediated processes.
authors.affiliation: Division of Crop Production, Central Rice Research Institute, Cuttack, 753006, Orissa, India. suvendu.bls@gmail.com
authors.forename: Suvendu
authors.initials: S
authors.lastname: Das
authors.forename: P
authors.initials: P
authors.lastname: Bhattacharyya
authors.forename: T K
authors.initials: TK
authors.lastname: Adhya
mesh_terms: D000383:Agriculture; D000469:Alkaline Phosphatase / Q000032:analysis; D018533:Biomass; D002245:Carbon Dioxide / Q000032:analysis*; D004784:Environmental Monitoring; D004798:Enzymes / Q000032:analysis*; D005452:Fluoresceins / Q000032:analysis; D006358:Hot Temperature; D012275:Oryza / Q000254:growth & development; D010088:Oxidoreductases / Q000032:analysis; D012987:Soil / Q000737:chemistry*; D012988:Soil Microbiology; D012989:Soil Pollutants / Q000032:analysis*; D014329:Tropical Climate; D014510:Urease / Q000032:analysis; D001617:beta-Glucosidase / Q000032:analysis
chemical_list: D004798:Enzymes; D005452:Fluoresceins; D012987:Soil; D012989:Soil Pollutants; D002245:Carbon Dioxide; D010088:Oxidoreductases; D000469:Alkaline Phosphatase; D001617:beta-Glucosidase; D014510:Urease; C018506:diacetylfluorescein