title: [Seasonal dynamics of soil net nitrogen mineralization under moss crust in Shapotou region, northern China].
abstract: Seasonal variations of soil inorganic nitrogen (N) pool and net N transformation rate in moss-covered soil and in the bare soil were comparatively observed by incubating intact soil columns with parafilm capping in the field in a natural vegetation area of Shapotou, southeastern fringe of the Tengger Desert. We found pronounced seasonal variations in soil available N content and net N transformation rate in both moss-covered soil and bare soil, with significant differences among different months. In non-growing season, soil available N content and net N transformation rate were significantly higher in March and October than in other months. Furthermore, immobilization was the dominant form of N mineralization, and no significant difference in net soil N mineralization rate was found between the two sampling soils. In growing season, soil available N content and net N transformation rate markedly increased and reached their peak values during June to August (17.18 mg x kg(-1) and 0.11 mg x kg(-1) x d(-1), respectively). Both soil net nitrification and N mineralization rates in moss-covered soil were significantly higher than in bare soil. Soil ammonium and nitrate N content in April and May were higher in moss-covered soil (2.66 and 3.16 mg x kg(-1), respectively) than in bare soil (1.02 and 2.37 mg x kg(-1), respectively); while the tendency was the converse in June and September, with 7.01 mg x kg(-1) for soil ammonium content and 7.40 mg x kg(-1) for nitrate N content in bare soil, and they were 6.39 and 6.36 mg x kg(-1) in moss-covered soil, respectively. Therefore, the existence and succession of moss crusts could be considered as one of the important biological factors affecting soil N cycling through regulating soil available N content and promoting soil N mineralization process.
authors.forename: Rui
authors.initials: R
authors.lastname: Hu
authors.forename: Xin-ping
authors.initials: XP
authors.lastname: Wang
authors.forename: Yan-xia
authors.initials: YX
authors.lastname: Pan
authors.forename: Ya-feng
authors.initials: YF
authors.lastname: Zhang
authors.forename: Hao
authors.initials: H
authors.lastname: Zhang
authors.forename: Ning
authors.initials: N
authors.lastname: Cheng
mesh_terms: D044002:Bryophyta; D002681:China; D009566:Nitrates; D058465:Nitrification; D009584:Nitrogen / Q000032:analysis*; D058458:Nitrogen Cycle; D012621:Seasons; D012987:Soil / Q000737:chemistry*; D012988:Soil Microbiology
chemical_list: D009566:Nitrates; D012987:Soil; D009584:Nitrogen