title: Soil biochemical responses to nitrogen addition in a bamboo forest.
abstract: Many vital ecosystem processes take place in the soils and are greatly affected by the increasing active nitrogen (N) deposition observed globally. Nitrogen deposition generally affects ecosystem processes through the changes in soil biochemical properties such as soil nutrient availability, microbial properties and enzyme activities. In order to evaluate the soil biochemical responses to elevated atmospheric N deposition in bamboo forest ecosystems, a two-year field N addition experiment in a hybrid bamboo (Bambusa pervariabilis × Dendrocalamopsis daii) plantation was conducted. Four levels of N treatment were applied: (1) control (CK, without N added), (2) low-nitrogen (LN, 50 kg N ha(-1) year(-1)), (3) medium-nitrogen (MN, 150 kg N ha(-1) year(-1)), and (4) high-nitrogen (HN, 300 kg N ha(-1) year(-1)). Results indicated that N addition significantly increased the concentrations of NH4(+), NO3(-), microbial biomass carbon, microbial biomass N, the rates of nitrification and denitrification; significantly decreased soil pH and the concentration of available phosphorus, and had no effect on the total organic carbon and total N concentration in the 0-20 cm soil depth. Nitrogen addition significantly stimulated activities of hydrolytic enzyme that acquiring N (urease) and phosphorus (acid phosphatase) and depressed the oxidative enzymes (phenol oxidase, peroxidase and catalase) activities. Results suggest that (1) this bamboo forest ecosystem is moving towards being limited by P or co-limited by P under elevated N deposition, (2) the expected progressive increases in N deposition may have a potential important effect on forest litter decomposition due to the interaction of inorganic N and oxidative enzyme activities, in such bamboo forests under high levels of ambient N deposition.
authors.affiliation: College of Forestry, Sichuan Agricultural University, Ya'an, Sichuan, China.
authors.forename: Li-hua
authors.initials: LH
authors.lastname: Tu
authors.affiliation: College of Forestry, Sichuan Agricultural University, Ya'an, Sichuan, China.
authors.forename: Gang
authors.initials: G
authors.lastname: Chen
authors.affiliation: College of Forestry, Sichuan Agricultural University, Ya'an, Sichuan, China.
authors.forename: Yong
authors.initials: Y
authors.lastname: Peng
authors.affiliation: College of Forestry, Sichuan Agricultural University, Ya'an, Sichuan, China.
authors.forename: Hong-ling
authors.initials: HL
authors.lastname: Hu
authors.affiliation: College of Forestry, Sichuan Agricultural University, Ya'an, Sichuan, China.
authors.forename: Ting-xing
authors.initials: TX
authors.lastname: Hu
authors.affiliation: College of Forestry, Sichuan Agricultural University, Ya'an, Sichuan, China.
authors.forename: Jian
authors.initials: J
authors.lastname: Zhang
authors.affiliation: College of Forestry, Sichuan Agricultural University, Ya'an, Sichuan, China.
authors.forename: Xian-wei
authors.initials: XW
authors.lastname: Li
authors.affiliation: Personnel Department, Sichuan Agricultural University, Ya'an, Sichuan, China.
authors.forename: Li
authors.initials: L
authors.lastname: Liu
authors.affiliation: College of Horticulture, Sichuan Agricultural University, Ya'an, Sichuan, China.
authors.forename: Yi
authors.initials: Y
authors.lastname: Tang
mesh_terms: D000135:Acid Phosphatase / Q000378:metabolism; D000641:Ammonia / Q000378:metabolism; D000704:Analysis of Variance; D001272:Atmosphere / Q000737:chemistry*; D018533:Biomass; D002374:Catalase / Q000378:metabolism; D002681:China; D058440:Denitrification / Q000187:drug effects; D065928:Forests; D014442:Monophenol Monooxygenase / Q000378:metabolism; D058465:Nitrification / Q000187:drug effects; D009584:Nitrogen / Q000008:administration & dosage / Q000032:analysis / Q000378:metabolism*; D009195:Peroxidase / Q000378:metabolism; D031787:Sasa; D012987:Soil / Q000737:chemistry*; D012988:Soil Microbiology; D014508:Urea / Q000378:metabolism
chemical_list: D012987:Soil; D000641:Ammonia; D014508:Urea; D002374:Catalase; D009195:Peroxidase; D014442:Monophenol Monooxygenase; D000135:Acid Phosphatase; D009584:Nitrogen