Fertilizer nitrogen budget in a Scots pine ecosystem attained by using root-isolated plots and15N tracer technique
The distribution and quantitative recovery of isotopically labelled fertilizer N was studied in aPinus sylvestris L. stand in central Sweden. The investigation was carried out with root-isolated plots, area 31.2 m2, having a Scots pine aged 120–140 years in the centre of each plot. The fertilizer application rate was 100 kg ammonium nitrate-N per hectare, with either ammonium or nitrate being enriched with15N. The treatments comprised both a single and a split application.
The analyses of needle biomass, collected during the first growing season showed that the proportion of labelled N in Ntot was greater in current needles than in older needles. Moreover, the isotopic enrichment was higher in treatments with labelled nitrate than in those with equivalent amount of labelled ammonium.
Two growing seasons after fertilization the trees were felled and the distribution of labelled N in the system was determined. The study proved that the greatest proportion of labelled N in Ntot was in the needles and shoots of current and previous year's growth. The lowest proportion of labelled N was found in the stem wood and coarse roots.
The proportion of labelled N in needles and shoots showed a tendency to increase with height in the crown. As regards bark and wood, the corresponding figures increased from the base to the top of the stem, and was higher in bark than in wood.
Between 12 and 28% of the supplied N was recovered in trees, half of which in the needle biomass. In the above-ground parts of the shrub layer 3 to 13% of applied N was recovered. The corresponding recovery figure in the soil varied between 37 and 59% (excluding roots, but including litter and bottom layer). Between 5–8% was recovered in roots <30 mm. On the average, 79% of the supplied N was recovered in the studied part of the system. No significant differences in total15n recovery were found between treatments with ammonium or nitrate source of N, or those with different application techniques.
The labelled N not recovered in the investigated part of the system, had presumably been lost by leaching.
Key wordsFertilization Immobilization Nitrogen-15 Nitrogen budget Pinus sylvestris Scots pine
Unable to display preview. Download preview PDF.
- 1.Albrektson A 1980 Biomass of scots pine (Pinus sylvestris L.) amount-development of mensuration. Swedish University of Agricultural Sciences, Department of Silviculture. Report no. 2.Google Scholar
- 2.Baker J B, Switzer G L and Nelson L E 1974 Biomass production and nitrogen recovery after fertilization of young loblolly pines. Soil Sci. Soc. Am. Proc. 38, 958 61.Google Scholar
- 3.Björkman E and Lundeberg G 1971 Studies of root competition in a poor pine forest by supply of labelled nitrogen and phosphorus. Studia Forestalia Suecica No. 94.Google Scholar
- 4.Björkman E, Lundeberg G and Nômmik H 1967 Distribution and balance of N15 labeled fertilizer nitrogen applied to young pine trees (Pinus silvestris L.). Studia Forestalia Suecica 48.Google Scholar
- 5.Bråkenhielm S 1978 Invantjärnsheden, Jädraås.-Regional physiography and description of the research area. technical Report No. 16, Swedish University of Agricultural Sciences. Uppsala.Google Scholar
- 6.Jansson S L 1958 Tracer studies on nitrogen transformations in soil with special attention to mineralisation-immobilization relationships. Kungl. Lantbrukshögskolans Ann. 24, 101–361.Google Scholar
- 7.Knowles R 1975 Interpretation of recent15N studies of nitrogen in forest systems.In Bernier B and Winget C H (eds) Forest Soils and Forest Land Management. Proc. 4th N. Am. For. Soils Conf., Laval Univ. Press, Quebec.Google Scholar
- 8.Lindroth A and Perttu K 1981 The local climate of Stor- and Lillmyren at Jädraås during the period 1979–1980. Technical Report No. 13. Energy Forest Project. Swedish University of Agricultural Sciences. Uppsala.Google Scholar
- 9.Mead D J 1972 Movement of added nitrogen and phosphorus in a pine forest ecosystem. Diss. Abstr. International 33, 524-B.Google Scholar
- 12.Miller H G, Miller J D and Pauline O J L 1976 Effect of nitrogen supply on nutrient uptake in corsican pine. J. Appl. Ecol. 13, 955–966.Google Scholar
- 13.Nômmik H 1966 The uptake and translocation of fertilizer N15 in young trees of Scots pine and Norway spruce. Studia Forestalia Suecica 35.Google Scholar
- 14.Nômmik H 1971 A modified procedure for determination of organic carbon in soils by wet combustion. Soil Sci. 111, 330–336.Google Scholar
- 15.Nômmik H and Möller G 1981 Nitrogen recovery in soil and needle biomass after fertilization of a Scots pine stand, and growth responses obtained. Studia Forestalia Suecica 159.Google Scholar
- 16.Nômmik H and Popović B 1967 Die Translokation von15N,90Sr und137Cs sowie die Verlagerung einiger Nährstoffe in verschiedenen Pflanzenteilen bei der Kiefer. Angew. Bot. 41, 181–193.Google Scholar
- 17.Paavilainen E 1973 Studies on the uptake of fertilizer nitrogen by Scots pine using15N labeled urea. Metsantutkimuslaitoksen Jalkaisuja 79 (No. 2), 47.Google Scholar
- 18.Popvić B and Burgtorf H 1964 Upptagning av växtnäring efter gödsling av ett tallbestånd i Lappland. Inst. f. skogsekologi, Skogshögskolan. rapporter och Uppsatser Nr 4.Google Scholar
- 19.Rittenberg T 1946 The preparation of gas samples for mass spectrographic isotopic analysis in preparation and measurements of isotopic tracers.In Symposium: Preparation and measurements of isotopic tracers. Ann. Arbor, Michigan 31, 42.Google Scholar
- 20.Tamm C O 1963 Upptagning av växtnäring efter gödsling av gran- och tallbestånd. Inst. f. skogsekologi, Skogshögskolan. Rapporter och Uppsatser Nr 1.Google Scholar
- 21.Tamm C O 1980 Response of spruce forest ecosystems to controlled changes in nutrient regime, maintained over periods up to 13 years. International UNESCO-MABI IUFRO Symposium. Stability of spruce forest ecosystems. University of Agriculture, Brno CSSR 423–433.Google Scholar
- 22.Wiklander G 1977 Skogsgödslingens inverkan på mark och vatten. Sv. skogsvårdsförb. tidskr. 75, 179–187.Google Scholar
- 23.Worsnop G and Will G M 1980 Fate of15N urea fertilizer applied to a recently thinned Radiata pine stand on a pumice soil. N. Z. J. For. Sci. 10, 381–394.Google Scholar
- 24.Grip H 1982 Water chemistry and runoff in forest streams at Kloten. UNGI Rapport Nr 58. Uppsala University, Department of Physical Geography, pp 1–144.Google Scholar