LeBauer D S, Treseder K K. Nitrogen limitation of net primary productivity in terrestrial ecosystems is globally distributed [J]. Ecology,2008,89(2):371-379
[2]
Bond G. Some aspects of translocation in root nodule plants [J]. Journal of Experimental Botany,1956,7(3):387-394
[3]
Leaf G, Gardner I G, Bond G. Observations on the composition and metabolism of the nitrogen-fixing root nodules of Alnus [J]. Journal of Experimental Botany,1958,9(3):320-331
[4]
Adams M A, Grierson P F. Stable isotopes at natural abundance in terrestrial plant ecology and ecophysiology: An update [J]. Plant Biology,2001,3(4):299-310
[5]
Booth M S, Stark J M, Rastetter E. Controls on nitrogen cycling in terrestrial ecosystems: A synthetic analysis of literature data [J]. Ecological Monographs,2005,75(2):139-157
[6]
Friedrich U, Falk K, Bahlmann E, et al. Fate of airborne nitrogen in heathland ecosystems: A 15N tracer study [J]. Global Change Biology,2011,17(4):1549-1559
[7]
Schroeder-Moreno M S, Greaver T L, Wang S X, et al. Mycorrhizal-mediated nitrogen acquisition in switchgrass under elevated temperatures and N enrichment [J]. Bioenergy,2012,4(3):266-276
[8]
Wu H H, Dannenmann M, Fanselow N, et al. Feedback of grazing on gross rates of N mineralization and inorganic N partitioning in steppe soils of Inner Mongolia[J]. Plant Soil,2011,340(1/2):127-139
Harrison K A, Bol R, Bardgett R D. Do plant species with different growth strategies vary in their ability to compete with soil microbes for chemical forms of nitrogen? [J]. Soil Biology & Biochemistry,2008,40(1):228-237
[12]
Harrison K A, Bol B, Bardgett R D. Preferences for different nitrogen forms by coexisting plant species and soil microbes [J]. Ecology,2007,88(4):989-999
[13]
Xu Y Q, He J C, Cheng W X, et al. Natural 15N abundance in soils and plants in relation to N cycling in a rangeland in Inner Mongolia [J]. Journal of Plant Ecology,2010,3(3):201-207
[14]
Rütting T, Clough T J, Müller C, et al. Ten years of elevated atmospheric carbon dioxide alters soil nitrogen transformations in a sheep-grazed pasture [J]. Global Change Biology,2010,16(9):2530-2542
[15]
Müller C, Laughlin R J, Christie P, et al. Effects of repeated fertilizer and cattle slurry applications over 38 years on N dynamics in a temperate grassland soil [J]. Soil Biology & Biochemistry,2011,43(6):1362-1371
[16]
Barker C C, Hughes I W, Young G T. Amino-acids and peptides. Part V, determination of L-glutamic acid by the isotope dilution method [J]. Journal of the Chemical Society,1951:3047-3051
[17]
Higginson W C E, Sutton D. The oxidation of hydrazine in aqueous solution. Part Ⅱ, the use of 15N as a tracer in the oxidation of hydrazine [J]. Journal of the Chemical Society,1953:1402-1406
[18]
Kirkham D, Bartholomew W V. Equations for following nutrient transformations in soil, utilizing tracer data [J]. Soil Science Society of America Journal,1954,18(1):33-34
[19]
Robson T M, Baptist F, Clément J C, et al. Land use in subalpine grasslands affects nitrogen cycling via changes in plant community and soil microbial uptake dynamics [J]. Journal of Ecology,2010,98(1):62-73
[20]
Holst J, Liu C Y, Brüggemann N, et al. Microbial N turnover and N-oxide (N2O/NO/NO2) fluxes in semi-arid grassland of Inner Mongolia [J]. Ecosystems,2007,10(4):623-634
[21]
Müller C, Rütting T, Kattge J, et al. Estimation of parameters in complex 15N tracing models by Monte Carlo sampling [J]. Soil Biology & Biochemistry,2007,39(3):715-726
[22]
Hu S, Chapin III F S, Firestone M K, et al. Nitrogen limitation of microbial decomposition in a grassland under elevated CO2 [J]. Nature,2001,409(6817):188-191
[23]
Song M H, Xu X L, Hu Q W, et al. Interactions of plants species mediated plant competition for inorganic nitrogen with soil microorganisms in an alpine meadow [J]. Plant Soil,2007,297(1/2):127-137
[24]
Wu H, Dannenmann M, Wolf B, et al. Seasonality of soil microbial nitrogen turnover in continental steppe soils of Inner Mongolia [J]. Ecosphere,2012,3(4):34
[25]
Wang S P, Li Y H. The influence of different stocking rates and grazing periods on the chemical components in feces of grazing sheep and relationship among the fecal components [J]. Acta Zoonvtrimenta Sinica,1997,9(2):49-56
[26]
Templer P H, Arthur M A, Lovett G M, et al. Plant and soil natural abundance δ15N: Indicators of relative rates of nitrogen cycling in temperate forest ecosystems [J]. Oecologia,2007,153(2):399-406
[27]
Bai E, Houlton B Z. Coupled isotopic and process-based modeling of gaseous nitrogen losses from tropical rain forests [J]. Global Biogeochemical Cycles,2009,23(2):GB2011
[28]
Coetsee C, Stock W D, Craine J. Do grazers alter nitrogen dynamics on grazing lawns in a South African savannah [J]. African Journal of Ecology,2010,49(1):62-69
Frank D A, Evans R D. Effects of native grazers on grassland N cycling in Yellowstone National Park [J]. Ecology,1997,78(7): 2238-2248
[31]
Cheng W X, Chen Q S, Xu Y Q, et al. Climate and ecosystem 15N natural abundance along a transect of Inner Mongolian grasslands: Contrasting regional patterns and global patterns [J]. Global Biogeochemical Cycles,2009,23(2):GB2005
[32]
Craine J M, Ballantyne F, Peel M, et al. Grazing and landscape controls on nitrogen availability across 330 South African savanna sites [J]. Austral Ecology,2009,34(7):731-740
[33]
Hobbie E A, Jumpponen A, Trappe J. Foliar and fungal 15N:14N ratio reflect development of mycorrhizae and nitrogen supply during primary succession:Esting analytical models [J]. Oecologia,2005,146(2):258-268
[34]
Pardo L H, Templer P H, Goodale C L, et al. Regional assessment of N saturation using foliar and root delta 15N [J]. Biogeochemistry,2006,80(2):143-171
[35]
Taghizadeh-Toosi A, Clough T J, Condron L M, et al. Biochar incorporation into pasture soil suppresses in situ nitrous oxide emissions from ruminant urine patches [J]. Journal of Environmental Quality,2011,40(2):468-476
[36]
Zhang J B, Zhu T B, Cai Z C, et al. Effects of long-term repeated mineral and organic fertilizer applications on soil nitrogen transformations [J]. European Journal of Soil Science,2012,63(1):75-85
[37]
Zogg D G, Zak D R, Pregitzer K S, et al. Microbial immobilization and retention of anthropogenic nitrate in a northern hardwood forest [J]. Ecology,2000,81(7):1858-1866
[38]
Hodge A, Stewart J, Robinson D, et al. Spatial and physical heterogeneity of N supply from soil does not influence N capture by two grass species [J]. Functional Ecology,2000,14(5):645-653
[39]
Providoli I, Bugmann H, Siegwolf R, et al. Pathways and dynamics of 15NO3- and 15NH4+ applied in a mountain Picea abies forest and in a nearby meadow in central Switzerland [J]. Soil Biology & Biochemistry,2006,38(7):1645-1657
[40]
Friedrich U, Oheimb G V, Kriebitzsch W U, et al. Nitrogen deposition increases susceptibility to drought-experimental evidence with the perennial grass Molinia caerulea L. Moench [J]. Plant Soil,2012,353(1/2):59-71
[41]
Skinner R A, Ineson P, Jones H, et al. Heathland vegetation as a bio-monitor for nitrogen deposition and source attribution using δ15N values [J]. Atmospheric Environmental,2006,40(3):498-507
[42]
Dijkstra F A, Pendall E, Mosier A R, et al. Long-term enhancement of N availability and plant growth under elevated CO2 in a semi-arid grassland [J]. Functional Ecology,2008,22(6):975-982
[43]
Dijkstra F A, Blumenthal D, Morgan J A, et al. Contrasting effects of elevated CO2 and warming on nitrogen cycling in a semiarid grassland [J]. New Phytologist,2010,187(2):426-437
[44]
Müller C, Rütting T, Abbasi M K, et al. Effect of elevated CO2 on soil N dynamics in a temperate grassland soil [J]. Soil Biology & Biochemistry,2009,41(9):1996-2001
[45]
Mathieu O, Hénault C, Lévêque J, et al. Quantifying the contribution of nitrification and denitrification to the nitrous oxide flux using 15N tracers [J]. Environmental Pollution,2006,144(3):933-940
[46]
Raciti S M, Groffman P M, Fahey T J. Nitrogen retention in urban lawns and forests [J]. Ecological Applications,2008,18(7): 1615-1626
[47]
Johnson B G, Johnson D W, Chambers J C, et al. Fire effects on the mobilization and uptake of nitrogen by cheatgrass (Bromus tectorum L.) [J]. Plant Soil,2011,341(1/2):437-445
[48]
Certini G. Effects of fire on properties of forest soils: A review [J]. Oecologia,2005,143(1):1-10
[49]
Dannenmann M, Willibald G, Sippel S, et al. Nitrogen dynamics at undisturbed and burned Mediterranean shrublands of Salento Peninsula, Southern Italy [J]. Plant Soil,2011,343(1/2):5-15
[50]
Couto-Vázquez A, González-Prieto S J. Short- and medium-term effects of three fire fighting chemicals on the properties of a burnt soil [J]. Science of the Total Environment,2006,371(1):353-361
[51]
González-Prieto S J, Villar M C, Carballas T. Availability of 15N from pioneer herbaceous plants to pine seedlings in reclaimed burnt soils [J]. Rapid Communications in Mass Spectrometry,2008,22(18):2799-2802
[52]
Cech P G, Edwards P J, Venterink H O. Why is abundance of herbaceous legumes low in African Savanna? A test with two model species [J]. Biotropica,2010,42(5):580-589
[53]
Ayres E, Mromph K M, Cook R, et al. The influence of below-ground herbivory and defoliation of a legume on nitrogen transfer to neighbouring plants [J]. Functional Ecology,2007,21(2):256-263
[54]
Rasmussen J, Eriksen J, Jensen E S, et al. In situ carbon and nitrogen dynamics in ryegrass-clover mixtures: Transfers, deposition and leaching [J]. Soil Biology & Biochemistry,2007,39(3):804-815
[55]
Wang C H, Butterbach-Bahl K, Han Y, et al. The effects of biomass removal and N addition on microbial N transformation and biomass at different vegetation types in an old-field ecosystem in northern China [J]. Plant Soil,2011,340(1/2):397-411
[56]
Arneth A, Harrison S P, Zaehle S, et al. Terrestrial biogeochemical feedbacks in the climate system [J]. Nature Geoscience,2010,3(8):525-532
[57]
Mannel T T, Auerswald K, Schnyder H. Altitudinal gradients of grassland carbon and nitrogen isotope composition are recorded in the hair of grazer [J]. Global Ecology and Biogeography,2007,16(5):583-592
[58]
Bijoor N S, Czimczik C I, Pataki D E, et al. Effects of temperature and fertilization on nitrogen cycling and community composition of an urban lawn [J]. Global Change Biology,2008,14(9):2119-2131
[59]
Murphy B P, Bowman D M. The carbon and nitrogen isotope composition of Australian grasses in relation to climate [J]. Functional Ecology,2009,23(6):1040-1049
[60]
McKinley D C, Romero J C, Hungate B A, et al. Does deep soil N availability sustain long-term ecosystem responses to elevated CO2? [J]. Global Change Biology,2009,15(8):2035-2048
