N2 fixation and nitrogen allocation to above and below ground plant parts in red clover-grasslands

Boller BC, Nösberger J (1987) Symbiotically fixed nitrogen from field-grown white and red clover mixed with ryegrasses at low levels of 15N-fertilization. Plant Soil 104:219–226

Carlsson G (2005) Input of Nitrogen from N2 Fixation to Northern Grasslands. Doctoral Thesis No. 2005:76. Swedish University of Agricultural Sciences. Acta Universitatis Agriculturae Sueciae, Umeå. pp 50

Carlsson G, Huss-Danell K (2003) Nitrogen fixation in perennial forage legumes in the field. Plant Soil 253:353–372

Carlsson G, Palmborg C, Huss-Danell K (2006) Discrimination against 15N in three N2-fixing Trifolium species as influenced by Rhizobium strain and plant age. Acta Agric Scand B Soil Plant Sci 56:31–38

Ericson L (2005) Norrländsk växtodling. Swedish University of Agricultural Sciences, Umeå. http://www.njv.slu.se/nvo/NVO2005.pdf Accessed 2 October 2006. (In Swedish)

Eriksen J, Pedersen L, Jørgensen JR (2006) Nitrate leaching and bread-making quality of spring wheat following cultivation of different grasslands. Agric Ecosyst Environ 116:165–175

Frame J, Charlton JFL, Laidlaw AS (1998) Temperate forage legumes. CAB International, Wallingford, Oxon, pp 327

Fried M, Danso SKA, Zapata F (1983) The methodology of measurement of N2 fixation by non-legumes as inferred from field experiments with legumes. Can J Microbiol 29:1053–1062

Gustavsson A-M (1989) Influence of N-fertilization and clover content in grassland for cutting. Grovfoder Forskning – Tillämpning (Grass and Forage Reports), Swedish University of Agricultural Sciences, Uppsala, No. 1:1989, pp 25–44. (In Swedish with English summary)

Högberg P (1997) 15N natural abundance in soil–plant systems. New Phytol 137:179–203

Høgh-Jensen H, Schjørring JK (1994) Measurement of biological dinitrogen fixation in grassland: comparison of the enriched 15N dilution and the natural 15N abundance methods at different nitrogen application rates and defoliation frequencies. Plant Soil 166:153–163

Høgh-Jensen H, Schjørring JK (1997) Residual nitrogen effect of clover-ryegrass swards on yield and N uptake of a subsequent winter wheat crop as studied by use of 15N methodology and mathematical modelling. Eur J Agron 6:235–243

Høgh-Jensen H, Schjørring JK (2001) Rhizodeposition of nitrogen by red clover, white clover and ryegrass leys. Soil Biol Biochem 33:439–448

Høgh-Jensen H, Loges R, Jørgensen FV, Vinther FP, Jensen ES (2004) An empirical model for quantification of symbiotic nitrogen fixation in grass-clover mixtures. Agric Syst 82:181–194

Huss-Danell K, Chaia E (2005) Use of different plant parts to study N2 fixation with 15N techniques in field-grown red clover (Trifolium pratense L.). Physiol Plant 125:21–30

Jørgensen FV, Ledgard SF (1997) Contribution from stolons and roots to estimates of the total amount of N2 fixed by white clover (Trifolium repens L.). Ann Bot 80:641–648

Jumpponen A, Högberg P, Huss-Danell K, Mulder CPH (2002) Interspecific and spatial differences in nitrogen uptake in monocultures and two-species mixtures in north European grasslands. Funct Ecol 16:454–461

Nesheim L, Boller BC (1991) Nitrogen fixation by white clover when competing with grasses at moderately low temperatures. Plant Soil 133:47–56

Nesheim L, Øyen J (1994) Nitrogen fixation by red clover (Trifolium pratense L.) grown in mixtures with timothy (Phleum pratense L.) at different levels of nitrogen fertilization. Acta Agric Scand B Soil Plant Sci 44:28–34

Phillips JM, Hayman DS (1970) Improved procedure for clearing roots and staining parasitic and vesicular-arbuscular mycorrhizal fungi for rapid assessment of infection. Trans Br Mycol Soc 55:158–161

Schoeneberger MM, Volk RJ, Davey CV (1989) Selection of reference plants and methods for estimating N2 fixation in mycorrhizal leguminous plants. Soil Sci Soc Am J 53:1425–1429

Shearer G, Kohl DH (1993) Natural abundance of 15N: fractional contribution of two sources to a common sink and use of isotope discrimination. In: Knowles R, Blackburn TH (eds) Nitrogen isotope techniques. Academic Press, San Diego, pp 89–125

Vinther FP (2006) Effects of cutting frequency on plant production, N-uptake and N2 fixation in above- and below-ground plant biomass of perennial ryegrass-white clover swards. Grass Forage Sci 61:154–163

Zar JH (1999) Biostatistical analysis (4th ed). Prentice Hall Inc., New Jersey, pp 663