Effects of carbon and phosphorus addition on microbial respiration, N2O emission, and gross nitrogen mineralization in a phosphorus-limited grassland soil
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Soil microbes are frequently limited by carbon (C), but also have a high phosphorus (P) requirement. Little is known about the effect of P availability relative to the availability of C on soil microbial activity. In two separate experiments, we assessed the effect of P addition (20 mg P kg−1 soil) with and without glucose addition (500 mg C kg−1 soil) on gross nitrogen (N) mineralization (15N pool dilution method), microbial respiration, and nitrous oxide (N2O) emission in a grassland soil. In the first experiment, soils were incubated for 13 days at 90% water holding capacity (WHC) with addition of NO3− (99 mg N kg−1 soil) to support denitrification. Addition of C and P had no effect on gross N mineralization. Initially, N2O emission significantly increased with glucose, but it decreased at later stages of the incubation, suggesting a shift from C to NO3− limitation of denitrifiers. P addition increased the N2O/CO2 ratio without glucose but decreased it with glucose addition. Furthermore, the 15N recovery was lowest with glucose and without P addition, suggesting a glucose by P interaction on the denitrifying community. In the second experiment, soils were incubated for 2 days at 75% WHC without N addition. Glucose addition increased soil 15N recovery, but had no effect on gross N mineralization. Possibly, glucose addition increased short-term microbial N immobilization, thereby reducing N-substrates for nitrification and denitrification under more aerobic conditions. Our results indicate that both C and P affect N transformations in this grassland soil.
Keywords15N recovery Denitrification Grassland Gross N mineralization Microbial respiration N2O emission
We thank Hero Tahaei and Janani Vimalathithen for their assistance in soil chemical analyses. This research was financially supported by the Australian Research Council (FT100100779).
- Firestone MK (1982) Biological denitrification. In: Stevenson FJ (Ed) Nitrogen in agricultural soils. Am Soc Agron, Madison, WI, USA, pp. 289–326Google Scholar
- Firestone MK, Davidson EA (1989) Microbiological basis of NO and N2O production and consumption in soil. In: Andreae MO, Schimel DS (eds) Exchange of trace gases between terrestrial ecosystems and the atmosphere. Wiley, New York, pp 7–21Google Scholar
- Forster P, Ramaswamy V, Artaxo P et al (2007) Changes in atmospheric constituents and in radiative forcing. In: Solomon S, Qin D, Manning M et al (eds) Climate change 2007: the physical science basis. Contribution of working group I to the fourth assessment report of the intergovernmental panel on climate change. Cambridge University Press, Cambridge, pp 129–234Google Scholar
- Mori T, Ohta S, Ishizuka S, Konda R, Wicaksono A, Heriyanto J, Hardjono A (2013) Effects of phosphorus addition with and without ammonium, nitrate, or glucose on N2O and NO emissions from soil sampled under Acacia mangium plantation and incubated at 100% of the water-filled pore space. Biol Fertil Soils 49:13–21CrossRefGoogle Scholar
- Mori T, Wachrinrat C, Staporn D, Meunpong P, Suebsai W, Matsubara K, Boonsri K, Lumban W, Kuawong M, Phukdee T, Srifai J, Boonman K (2017) Effects of phosphorus addition on nitrogen cycle and fluxes of N2O and CH4 in tropical tree plantation soils in Thailand. Agric Nat Resour 51:91–95Google Scholar
- Olsen SR, Sommers LE (1982) Phosphorus. In: Pace AL, Miller RH, Keeney DR (eds) Methods of soil analysis. Part 2. Chemical and microbiological properties, 2nd edn. Am Soc Agron, Inc., Madison, WI, pp 403–430Google Scholar
- Robertson GP, Groffman PM (2007) Nitrogen transformations. Soil Microbiol Ecol. Biochemist 3:341–364Google Scholar
- Weier KL, Doran JW, Power JF, Walters DT (1993) Denitrification and dinitrogen/nitrous oxide ratio as affected by soil water, available carbon dioxide and nitrous oxide production in tilled and nontilled soils. Soil Sci Soc Am J 48:1267–1272Google Scholar
- Weil RR, Brady NC (2016) The nature and properties of soils, 15th edn. Pearson, Boston, p 912Google Scholar