title: Effects of nitrogen and phosphorus additions on soil microbial biomass and community structure in two reforested tropical forests.
abstract: Elevated nitrogen (N) deposition may aggravate phosphorus (P) deficiency in forests in the warm humid regions of China. To our knowledge, the interactive effects of long-term N deposition and P availability on soil microorganisms in tropical replanted forests remain unclear. We conducted an N and P manipulation experiment with four treatments: control, N addition (15 g N m(-2)·yr(-1)), P addition (15 g P m(-2)·yr(-1)), and N and P addition (15 + 15 g N and P m(-2)·yr(-1), respectively) in disturbed (planted pine forest with recent harvests of understory vegetation and litter) and rehabilitated (planted with pine, but mixed with broadleaf returning by natural succession) forests in southern China. Nitrogen addition did not significantly affect soil microbial biomass, but significantly decreased the abundance of gram-negative bacteria PLFAs in both forest types. Microbial biomass increased significantly after P addition in the disturbed forest but not in the rehabilitated forest. No interactions between N and P additions on soil microorganisms were observed in either forest type. Our results suggest that microbial growth in replanted forests of southern China may be limited by P rather than by N, and this P limitation may be greater in disturbed forests.
authors.affiliation: Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, China.|State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Science, Chinese Academy of Sciences, Beijing 100085, China.
authors.forename: Lei
authors.initials: L
authors.lastname: Liu
authors.affiliation: Department of Geosciences and Natural Resource Management, University of Copenhagen, Rolighedsvej 23, DK-1958 Frederiksberg C, Denmark.
authors.forename: Per
authors.initials: P
authors.lastname: Gundersen
authors.affiliation: Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Zhang
authors.affiliation: Institute of Tropical Pratacultural Science, Zhanjiang Normal University, Zhanjiang, China.
authors.forename: Tao
authors.initials: T
authors.lastname: Zhang
authors.affiliation: Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, China.|University of Chinese Academy of Science, Beijing, China.
authors.forename: Hao
authors.initials: H
authors.lastname: Chen
authors.affiliation: Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, China.
authors.forename: Jiangming
authors.initials: J
authors.lastname: Mo
mesh_terms: D018533:Biomass; D057486:Carbon Cycle / Q000502:physiology; D002681:China; D017753:Ecosystem; D005227:Fatty Acids / Q000032:analysis; D005308:Fertilizers / Q000032:analysis*; D016468:Forestry / Q000379:methods; D006090:Gram-Negative Bacteria / Q000254:growth & development / Q000378:metabolism; D006094:Gram-Positive Bacteria / Q000254:growth & development / Q000378:metabolism; D064307:Microbiota / Q000187:drug effects*; D009566:Nitrates / Q000378:metabolism; D009584:Nitrogen / Q000378:metabolism*; D010710:Phosphates / Q000378:metabolism; D010758:Phosphorus / Q000378:metabolism*; D025341:Principal Component Analysis; D065947:Rainforest; D012987:Soil / Q000737:chemistry; D012988:Soil Microbiology
chemical_list: D005227:Fatty Acids; D005308:Fertilizers; D009566:Nitrates; D010710:Phosphates; D012987:Soil; D010758:Phosphorus; D009584:Nitrogen; C018279:sodium phosphate; C006568:ammonium nitrate