Effects of including forbs on N2-fixation and N yield in red clover-ryegrass mixtures
Legume biological nitrogen (N2)-fixation is stimulated by neighbouring non-fixing species, but studies of legume N2-fixation in temporary grasslands including non-leguminous forage herb (forb) species are rare.
We investigated N2-fixation, N yield, and total herbage production in a range of species mixtures consisting of three forb species—chicory (Cichorium intybus L.), ribwort plantain (Plantago lanceolata L.), and caraway (Carum carvi L.)—mixed into a traditional red clover (Trifolium pratense L.) and perennial ryegrass (Lolium perenne L.) mixture at two fertilisation levels.
The percentage of red clover N derived from the atmosphere (%Ndfa) was higher in mixtures containing non-legumes than in pure stand but, did not increase with inclusion of forbs. On a whole-seasonal basis, red clover in mixtures derived 90% or more of its N from fixation even when fertilised with 216 kg total N ha−1. Forbs, in particular chicory, reduced the amount of N2-fixation and total N yields by affecting the red clover proportion in the harvested biomass.
Generally, inclusion of forbs in red clover-ryegrass mixtures had no negative effect on total herbage production and percentage of legume N2-fixation. However, to maintain a high total N and N2-fixation yields, mixtures should not include a high seeding proportion of chicory.
KeywordsPlant diversity Temporary grassland Chicory Ribwort plantain Caraway Percentage of N2-fixation (%Ndfa)
This work was funded by the Green Development and Demonstration Program (GUDP project MultiPlant) as part of the Organic RDD-2 programme and coordinated by the International Centre for Research in Organic Food Systems (ICROFS).
- Burchill W, James EK, Li D, Lanigan GJ, Williams M, Iannetta PPM, Humphreys J (2014) Comparisons of biological nitrogen fixation in association with white red clover (Trifolium repens L.) under four fertiliser nitrogen inputs as measured using two 15N techniques. Plant Soil 385(1–2):287–302CrossRefGoogle Scholar
- Hakala K, Keskitalo M, Eriksson C (2008) Nutrient uptake and biomass accumulation for eleven different field crops. Agric Food Sci 18:366–387Google Scholar
- Hauggaard-Nielsen H, Gooding M, Ambus P, Corre-Hellou G, Crozat Y, Dahlmann C, Dibet A, Von Fragstein P, Pristeri A, Monti M (2009) Pea–barley intercropping for efficient symbiotic N2-fixation, soil N acquisition and use of other nutrients in European organic cropping systems. Field Crop Res 113:64–71CrossRefGoogle Scholar
- Søegaard K, Eriksen J, Askegaard M (2008) Herbs in grasslands—effect of slurry and grazing/cutting on species composition and nutritive value. Grassland Science in Europe 13:200–202Google Scholar
- Søegaard K, Eriksen J, Askegaard M (2011) Herbs in high producing organic grasslands–effect of management. Proceedings of the Third Scientific Conference of International Society of Organic Agriculture Research (ISOFAR): Organic Is Life—Knowledge for Tomorrow. Organic Crop Production, vol 1, pp 190–193Google Scholar
- Søegaard K, Eriksen J, Mortensen TB (2013) Species competition in multispecies grass swards. ICROFS News 3:12–13Google Scholar
- Stewart A (1996) Plantain (Plantago lanceolata)—a potential pasture species. In: Proceedings of the Conference-New Zealand Grassland Association, pp 77–86Google Scholar
- Unkovich M, Herridge D, Peoples M, Cadisch G, Boddey B, Giller K, Alves B, Chalk P (2008) Measuring plant associated nitrogen fixation in agricultural systems. Australian Centre for International Agricultural Research (ACIAR), Canberra, pp 131–188Google Scholar
- Younie D (2012) Grassland management for organic farmers. The Crowood Press, Marlborough, pp 18–33Google Scholar