Agroforestry Systems

, Volume 12, Issue 2, pp 173–185 | Cite as

Avoiding edge effects in agroforestry experiments; the use of neighbour-balanced designs and guard areas

  • S. Langton


A number of different types of edge effects on experimental plots are defined, and it is shown that they are frequently important in agroforestry experiments. Methods of eliminating edge effects, either at the design or the analysis stage, are described. Computer simulations, based on uniformity data, are used to investigate the efficacy of neighbour-balanced designs, with and without neighbour terms, for reducing the problem of neighbour effects between different treatments. It is concluded that, while neighbour-balanced designs may be useful in certain situations or in combination with other methods, it is preferable to eliminate edge effects by using adequate guard rows. Recommendations are therefore made concerning the correct use of guard areas in agroforestry experimentation.

Key words

Agroforestry experiments edge effects neighbour-balanced designs statistical analysis guard areas 


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Copyright information

© Kluwer Academic Publishers 1990

Authors and Affiliations

  • S. Langton
    • 1
  1. 1.Statistics Departmentt, AFRC Institute for Arable Crops ResearchRothamsted Experimental StationHarpendenUK

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