Nitrogen fixation by plants grown on reclaimed china clay waste.

Published online
01 Jan 1981
Content type
Journal article
Journal title
Journal of Applied Ecology

Skeffington, R. A. & Bradshaw, A. D.

Publication language


N fixation rates associated with various plant spp. growing on china clay waste materials were estimated using the acetylene reduction technique. Rates associated with leguminous species (Lupinus arboreus, Ulex europaeus, Trifolium repens) were at least 10 times greater than those of non-leguminous spp. Of the swards comprising non-leguminous spp., only those with Rumex acetosella or Festuca rubra and Agrostis tenuis fixed significant amounts of N, presumably in their rhizospheres. Low rates were detected in some other spp. The estimated rate of atmospheric input of combined N was greater than the input from any of the non-leguminous spp. There was no detectable fixation by free-living micro-organisms, except with an added C source. All rates were low, probably because of an exceptionally dry summer. Legumes are therefore recommended as the most valuable method of promoting N accumulation. Nevertheless up to 50 kg N/ha could be applied as fertilizer to Trifolium repens without affecting its fixation rate.

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