Abstract
Preliminary attempts to make retrospective studies of N balances and water stress in forest fertilization experiments by analyzing changes in the abundances of 15N and 13C, respectively, are discussed. Most evidence is from the Swedish Forest Optimum Nutrition Experiments, which have been running for two decades. Annual additions of N have been given either alone or in combination with other elements, notably P and K, every third year. Processes leading to loss of N, e.g. volatilization of ammonia, nitrification followed by leaching or denitrification, and denitrification alone, discriminate against the heavy isotope 15N. A correlation was found between fractional losses of added N and the change in δ15N (‰) during 19 years in current needles in a Scots pine forest, irrespective of source of N. Isotope effects were larger on urea than on ammonium nitrate plots (2 as compared to 9 δ15N (‰)) because of ammonia volatilization and higher rates of nitrification. They developed gradually over time, which opens possibilities to analyse the development of N saturation. However, the analysis may be confounded by shifts in 15N abundance of fertilizer N. In another trial, N isotope effects could be seen in both plants and soils 10 years after the last fertilization; they were smaller in soils because of a large pretreatment memory effect, but we expect them to persist there for decades.
The enzyme RuBisCo discriminates strongly against the heavy isotope 13C during photosynthesis, but this effect becomes less expressed as stomata close because of water stress. The supply of N may also affect the δ13C (‰) via effects on rates of photosynthesis, and the source of N may have an influence directly via non-RubisCo carboxylations, and indirectly via effects on water use efficiency. In a trial with Norway spruce, the effect of N fertilization on the δ13C (‰) of current needles was strongly correlated with production and weakly so with foliar biomass a dry year, but not a wet year. This suggested that these variations are primarily related to induced differences in the balance between supply and demand for water. Hence, studies of {au13}C abundance can disentangle the role of water as such from its effects on mineralization of N and flow of N.
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References
Aber J D, Nadelhoffer K J, Steudler P and Melillo J M 1989 Nitrogen saturation in northern forest ecosystems. BioScience 39, 378–386.
Axelsson B 1985 Biomass dynamics in the nutrition experiment at Stråsan. J. Roy. Swed. Acad. Agric. For. Suppl. 17, 30–39.
Davidson E A, Hart S C and Firestone M K 1992 Internal cycling of nitrate in soils of a mature coniferous forest. Ecology 73, 1148–1156.
Drew M C and Saker L R 1975 Nutrient supply and the growth of the seminal root system in barley. II. Localized, compensatory increases in lateral root growth and rates of nitrate uptake when nitrate supply is restricted to only part of the root system. J. Exp. Bot. 26, 79–90.
Ericsson A 1978 Seasonal changes in transoocation of 14C from different age-classes of needles on 20-year-old Scots pine trees (Pinus silvestris). Physiol. Plant. 43, 351–358.
Farquhar G D 1991 Use of stable isotopes in evaluating plant water use efficiency. In Stable Isotopes in Plant Nutrition, Soil Fertility and Environmental Studies. pp 475–488, IAEA, Vienna.
Farquhar G D, O'Leary M H and Berry J A 1982 On the relationship between carbon isotope discrimination and photosynthesis. Aust. J. Plant. Physiol. 9, 121–137.
Farquhar G D and Richards P A 1984 Isotopic composition of plant carbon correlates with water use efficency of wheat genotypes. Aust. J. Plant. Physiol. 11, 339–352.
Field C B and Mooney H A 1986 The photosynthesis-nitrogen relationships in wild plants. In On the Economy of Plant Form and Function. Ed. TGivnish. pp 22–55. Cambridge University Press, Cambridge.
Francey R J and Farquhar G D 1982 An explanation of 13C/12C variations in tree rings. Nature 297, 28–31.
Francey R J, Gifford R M, Sharkey T D and Weir B 1985 Physiological influences on carbon isotope discrimination in huon pine (Lagarostrobos franklinii). Oecologia 66, 211–218.
Gebauer G and Schulze E-D 1991 Carbon and nitrogen isotope ratios in different compartments of a healthy and a declining Picea abies forest in the Fichtelgebirge, NE Bavaria. Oecologia 87, 198–207.
Gigon A and Rorison I H 1972 The response of some ecologically distinct plant species to nitrate-and to ammonium-nitrogen. J. Ecol. 60, 93–102.
Handley L L and Raven J A 1992 The use of natural abundance of nitrogen isotopes in plant physiology and ecology. Plant Cell Environ. 15, 965–985.
Högberg P 1990a 15N natural aburdance as a possible marker of the ectomycorrhizal habit of trees in mixed African woodlands. New Phytol. 115, 483–486.
Högberg P 1990b Forests losing large quantities of nitrogen have elevated 15N:14N ratios. Oecologia 84, 229–231.
Högberg P 1991 Development of 15N enrichment in a nitrogen-fertilized forest soil-plant system. Soil Biol. Biochem. 23, 335–338.
Högberg P and Johannisson C 1993 15N abundance of forests is correlated with losses of nitrogen. Plant and Soil 157, 147–150.
Högberg P, Johannisson C and Hällgren J-E 1993 Studies of 13C in the foliage reveal interactions between nutrients and water in forest fertilization experiments. Plant and Soil 152, 207–214.
Högberg P, Tamm C-O and Högberg M 1992 Variations in 15N abundance in a forest fertilization trial: Critical loads of N,N saturation, contamination and effects of revitalization fertilization. Plant and Soil 142, 211–219.
Högbom L and Högberg P 1991 Nitrate nutrition of Deschampsia flexuosa (L.) Trin. in relation to nitrogen deposition in Sweden. Oecologia 87, 488–494.
Holmen H, Nilsson Å, Popovic B and Wiklander G 1976 The optimum nutrition experiment Norrliden. A brief description of an experiment in young stand of Scots pine (Pinus silvestris L.). Res. Note No. 26. Dep. For. Ecol. For. Soils. Sch. For., Stockholm, Sweden. 34p.
Ingestad T 1979 Mineral nutrient requirements of Pinus svlvestris and Picea abies seedlings. Physiol. Plant. 45, 373–380.
Jansson S L 1958 Tracer studies on nitrogen transformations in soil with special attention to mineralization-immobilization relationships. Ann. R. Agr. Coll. Sweden 24, 101–361.
Johannisson C and Högberg P 1994 15N abundances of soils and plants along an experimentally induced forest nitrogen supply gradient. Oecologia 97, 322–325.
Kellner O 1993 Effects on associated flora of sylvicultural nitrogen fertilization repeated at long intervals. J. Appl. Ecol. 30, 563–574.
Kohl D H, Shearer G B and Commoner B 1973 Variation of 15N in corn and soil following application of fertilizer nitrogen. Soil Sci. Soc. Am. Proc. 37, 888–892.
Leavitt S W and Long A 1982 Evidence for 13C/12C fractionation between tree leaves and wood. Nature 298, 742–744.
Marschner H, Häussling M and George E 1991 Ammonium and nitrate uptake rates and rhizosphere pH in non-mycorrhizal roots of Norway spruce (Picea abies (L.) Karst.). Trees 5, 14–21.
Medina E and Minchin P 1980 Stratification of δ13C values of leaves in Amazonian rain forest. Oecologia 45, 377–378.
Meints V W, Boone L V and Kurtz L T 1975 Natural 15N abundance in soil, leaves, and grain as influenced by long term additions of fertilizer N at several rates. J. Environ. Qual. 4, 486–490.
Pate J S, Stewart G R and Unkovich M 1993 15N natural abundance of plant and soil components of a Banksia woodland ecosystem in relation to nitrate utilisation, life form, mycorrhizal status and N2-fixing abilities of component species. Plant Cell Environ. 16, 365–373.
Peterson B J and Fry B 1987 Stable isotopes in ecosystem studies. Ann. Rev. Ecol. Syst. 18, 293–320.
Raven J A and Farquhar G D 1990 The influence of N metabolism and organic acid synthesis on the natural abundance of isotopes of carbon in plants. New Phytol. 116, 505–529.
Raven J A, Wollenweber B and Handley L L 1992 A comparison of ammonium and nitrate as nitrogen sources for photolithotrophs. New Phytol. 121, 19–32.
Schulze E-D 1989 Air pollution and forest decline in a spruce (Picea abies) forest. Science 244, 776–783.
Shearer G B and Kohl D H 1986 N2-fixation in field settings: estimations based on natural 15N abundance. Aust. J. Plant. Physiol. 13, 699–757.
Shearer G B, Kohl D H and Commoner B 1974 The precision of determinations of nitrogen-15 in soils, fertilizers, and shelf chemicals. Soil Sci. 118, 308–316.
Shearer G B and Legg J O 1975 Variations in the natural abundance of 15N of wheat plants in relation to fertilizer applications. Soil Sci. Soc. Am. Proc. 39, 896–901.
Skeffington R A and Wilson E J 1988 Excess nitrogen deposition: Issues for consideration. Environ. Pollut. 54, 159–184.
Tamm C-O 1985 The Swedish optimum nutrition experiments in forest stands-aim, methods, yield, results. J. R. Swed. Acad. Agric. For. Suppl. 17, 9–29.
Tamm C-O 1989a Comparative and experimental approaches to the study of acid deposition effects on soils as substrate for forest growth. Ambio 18, 184–191.
Tamm C-O 1989b The role of field experiments in the study of soil-mediated effects of air pollution on forest trees. Comm. Norw. For. Res. Inst. 42, 179–196.
Tamm C-O 1991 Nitrogen in Terrestrial Ecosystems. Ecological Studies No. 81. Springer Verlag, Berlin. 115 p.
Tamm C-O, Aronsson A and Burgtorf H 1974a The optimum nutrition experiment Stråsan: A brief description of an experiment in a young stand of Norway spruce (Picea abies Karst.). Res. Note No. 17. Dep. For. Ecol. For. Soils, Sch. For., Stockholm, Sweden. 29 p.
Tamm C-O, Nilsson Å and Wiklander G 1974b The optimum nutrition experiment Lisselbo. A brief description of an experiment in a young stand of Scots pine (Pinus silvestris L.). Res. Note No. 18. Dep. For. Ecol. For. Soils, Sch. For., Stockholm, Sweden. 25 p.
Virginia R A, Jarrell W M, Rundel P W, Shearer G and Kohl D H 1988 The use of the variation in the natural abundance of 15N to assess symbiotic nitrogen fixation by woody plants. In Stable Isotopes in Ecological Research. Eds. P WRundel, J REhleringer and K ANagy. pp 375–394, Springer Verlag New York.
Vitousek P M, Shearer G and Kohl D H 1989 Foliar 15N natural abundance in Hawaiian rainforest: patterns and possible mechanisms. Oecologia 78, 383–388.
Vogel J C 1978 Recycling of carbon in a forest environment. Oecol. Plant. 13, 89–94.
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Högberg, P., Johnnisson, C., Högberg, M. et al. Measurements of abundances of 15N and 13C as tools in retrospective studies of N balances and water stress in forests: A discussion of preliminary results. Plant Soil 168, 125–133 (1995). https://doi.org/10.1007/BF00029321
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DOI: https://doi.org/10.1007/BF00029321