Skip to main content

Kelp (Laminaria digitata) increases germination and affects rooting and plant vigour in crops and native plants from an arable grassland in the Outer Hebrides, Scotland

Abstract

Kelp and other seaweeds are traditionally used in many parts of the world as a soil amendment on arable fields. Seaweeds contain biochemical compounds that can act as plant growth regulators in terrestrial plants. In a low-intensity arable grassland in northwest Scotland an organic fertilizer, kelp (Laminaria digitata) has been used for hundreds of years, due to its anticipated positive effect as a soil conditioner and provider of plant nutrients. In this study the effects of kelp on germination and rooting of crops and native plants from this area were investigated in soil-free media. Germination was studied by incubation in the presence of kelp solutions. Rooting of plant cuttings was assessed after a pulse treatment with kelp solutions, and indole-3 acetic acid (IAA) as a reference plant growth regulator. Germination percentage of Plantago lanceolata, Trifolium repens and Avena strigosa seeds increased significantly when incubated with 0.05% kelp solutions. Total root weight and the individual weight of roots produced in cuttings of Vigna radiata and P. lanceolata were significantly increased when exposed to a 0.5% solution of kelp. Plant vigour, assessed visually, decreased significantly for P. lanceolata exposed to kelp at concentrations of 0.5 and 5.0% indicating the presence of a threshold level for an inhibitory effect of kelp at these concentrations, which may be due to high salinity. The results confirmed the presence of plant growth regulators in kelp, and indicates that amendment with kelp may potentially affect plant community composition. The threshold levels where some plants responded negatively to kelp amendment were close to or lower than the theoretical concentrations of kelp in soil water at field conditions with the current doses used on the machair, indicating that care should be taken in either administering kelp at the appropriate dose or leaching out salt before application.

This is a preview of subscription content, access via your institution.

Fig. 1
Fig. 2
Fig. 3
Fig. 4
Fig. 5

References

  • Anonymous (1999) UK biodiversity group—tranche 2 action plans—volume V: maritime species and habitats. Machair habitat action plan. English Nature, Peterborough

    Google Scholar 

  • Angus S (2001) The Outer Hebrides. Moor and Machair. The White Horse, Cambridge and Isle of Harris, pp 195–243

    Google Scholar 

  • Bewley JD (1997) Seed germination and dormancy. Plant Cell 9:1055–1066

    Article  CAS  Google Scholar 

  • Blunden G, Gordon SM, Keysell GR (1982) Lysine betaine and other quaternary ammonium compounds from British species of the laminariales. J Nat Prod 45:449–452

    Article  CAS  Google Scholar 

  • Cayuela ML, Millner PD, Meyer SLF, Roig A (2008) Potential of olive mill waste and compost as biobased pesticides against weeds, fungi, and nematodes. Sci Total Environ 399:11–18

    Article  CAS  Google Scholar 

  • Chapman VJ, Chapman DJ (1980) Seaweeds and their uses, 3rd edn. Chapman and Hall Ltd, London, pp 30–43

    Google Scholar 

  • Connell JH, Slatyer RO (1977) Mechanisms of succession in natural communities and their role in community stability and organization. Am Nat 111:1119–1144

    Article  Google Scholar 

  • Crouch IJ, Van Staden J (1991) Evidence for rooting factors in a seaweed concentrate prepared from Ecklonia maxima. Plant Physiol 137:319–322

    Google Scholar 

  • Crouch IJ, Van Staden J (1993) Evidence for the presence of plant growth regulators in commercial seaweed products. Plant Growth Regul 13:21–29

    CAS  Google Scholar 

  • Crouch IJ, Smith MT, Van Staden J, Lewis MJ, Hoad GV (1992) Identification of auxins in a commercial seaweed concentrate. J Plant Physiol 139:590–594

    CAS  Google Scholar 

  • Dargie TDC (1998) Sand dune vegetation of Scotland: Western Isles. Main report: Vegetation and land cover types. Scottish Natural Heritage Research, Survey and Monitoring Report No. 96, pp 31–38

  • Eyras MC, Defosse GE, Dellatorre F (2008) Seaweed compost as an amendment for horticultural soils in Patagonia, Argentina. Compost Sci Util 16:119–124

    Google Scholar 

  • Finnie JF, Van Staden J (1985) The effect of seaweed concentrate and applied hormones on in vitro cultured tomato roots. J Plant Physiol 120:215–222

    CAS  Google Scholar 

  • Greger M, Malm T, Kautsky L (2007) Heavy metal transfer from composted macroalgae to crops. Eur J Agron 26:257–265

    Article  CAS  Google Scholar 

  • Hess CE (1961) The physiology of root initiation in easy- and difficult-to-root cuttings. Hormolog 3:3–6

    Google Scholar 

  • López-Mosquera ME, Pazos P (1997) Effects of seaweed on potato yields and soil chemistry. Biol Agric Hortic 14:199–206

    Google Scholar 

  • Parsons C, Caldwell CD, Norrie J (2001) Seaweed extract residue as a soil amendment. Hortscience 36:436

    Google Scholar 

  • Rolland F, Moore B, Sheen J (2002) Sugar sensing and signalling in plants. Plant Cell Supplement 2002:S185–S205

  • Temple WD, Bomke AA (1988) Effects of kelp (Macrocystis integrifolia) on soil chemical properties and crop response. Plant Soil 105:213–222

    Article  CAS  Google Scholar 

  • Thorsen MK, Hopkins DW, Woodward S, McKenzie BM (2010) Resilience of microorganisms and aggregation of a sandy calcareous soil to amendment with organic and synthetic fertilizer. Soil Use Management. doi:10.1111/j1475-2743.2010.00262.x

  • Williams ED (1983) Germinability and enforced dormancy in seeds of species of indigenous grassland. Ann Appl Biol 102:557–566

    Article  Google Scholar 

Download references

Acknowledgements

The authors would like to thank Jim McNicol (Biomathematics & Statistics Scotland) for advice on statistics, and Jacqueline Thompson (SCRI) for carrying out the elemental composition analysis of kelp. This work was funded by SCRI and the College of Life Science & Medicine at the University of Aberdeen. SCRI receives grant-in-aid support from The Scottish Government Rural and Environmental Research and Analysis Directorate.

Author information

Authors and Affiliations

Authors

Corresponding author

Correspondence to Blair M. McKenzie.

Rights and permissions

Reprints and Permissions

About this article

Cite this article

Thorsen, M.K., Woodward, S. & McKenzie, B.M. Kelp (Laminaria digitata) increases germination and affects rooting and plant vigour in crops and native plants from an arable grassland in the Outer Hebrides, Scotland. J Coast Conserv 14, 239–247 (2010). https://doi.org/10.1007/s11852-010-0091-6

Download citation

  • Received:

  • Revised:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1007/s11852-010-0091-6

Keywords

  • Kelp
  • Seaweed
  • Plant growth regulators
  • Germination
  • Rooting
  • Machair