title: Responses of absolute and specific soil enzyme activities to long term additions of organic and mineral fertilizer.
abstract: Long-term phosphorus (P) and nitrogen (N) applications may seriously affect soil microbial activity. A long-term field fertilizer application trial was established on reddish paddy soils in the subtropical region of southern China in 1998. We assessed the effects of swine manure and seven different rates or ratios of NPK fertilizer treatments on (1) the absolute and specific enzyme activities per unit of soil organic carbon (SOC) or microbial biomass carbon (MBC) involved in C, N, and P transformations and (2) their relationships with soil environmental factors and soil microbial community structures. The results showed that manure applications led to increases in the absolute and specific activities of soil β-1,4-glucosidase(βG), β-1,4-N-acetylglucosaminidase (NAG), and leucine aminopeptidase (LAP). The absolute and specific acid phosphatase (AP) activities decreased as mineral P fertilizer application rates and ratios increased. Redundancy analysis (RDA) showed that there were negative correlations between absolute and specific AP activities, pH, and total P contents, while there were positive correlations between soil absolute and specific βG, NAG, and LAP enzyme activities, and SOC and total N contents. RDA showed that the contents of actinomycete and Gram-positive bacterium PLFA biomarkers are more closely related to the absolute and specific enzyme activities than the other PLFA biomarkers (P<0.01). Our results suggest that both the absolute and specific enzyme activities could be used as sensitive soil quality indicators that provide useful linkages with the microbial community structures and environmental factors. To maintain microbial activity and to minimize environmental impacts, P should be applied as a combination of inorganic and organic forms, and total P fertilizer application rates to subtropical paddy soils should not exceed 44 kg P ha(-1) year(-1).
authors.affiliation: Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China. Electronic address: zhangxy@igsnrr.ac.cn.
authors.forename: Xinyu
authors.initials: X
authors.lastname: Zhang
authors.affiliation: Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China.
authors.forename: Wenyi
authors.initials: W
authors.lastname: Dong
authors.affiliation: Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China.
authors.forename: Xiaoqin
authors.initials: X
authors.lastname: Dai
authors.affiliation: Biosystems Engineering and Soil Science, University of Tennessee, Knoxville, TN 37996, USA.
authors.forename: Sean
authors.initials: S
authors.lastname: Schaeffer
authors.affiliation: Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China.
authors.forename: Fengting
authors.initials: F
authors.lastname: Yang
authors.affiliation: Biosystems Engineering and Soil Science, University of Tennessee, Knoxville, TN 37996, USA.
authors.forename: Mark
authors.initials: M
authors.lastname: Radosevich
authors.affiliation: Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China.
authors.forename: Lili
authors.initials: L
authors.lastname: Xu
authors.affiliation: Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China.
authors.forename: Xiyu
authors.initials: X
authors.lastname: Liu
authors.affiliation: Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China. Electronic address: sunxm@igsnrr.ac.cn.
authors.forename: Xiaomin
authors.initials: X
authors.lastname: Sun
mesh_terms: D000383:Agriculture / Q000379:methods*; D002681:China; D005308:Fertilizers; D009584:Nitrogen / Q000032:analysis; D010758:Phosphorus / Q000032:analysis; D012987:Soil; D012988:Soil Microbiology
chemical_list: D005308:Fertilizers; D012987:Soil; D010758:Phosphorus; D009584:Nitrogen
keywords: Mineral fertilizer; Paddy soil; Soil enzyme activity; Soil microbial community structure; Swine manure