A method of land evaluation including year to year weather variability

Land evaluation is sensitive to the effects of annual variability in weathe r. A method to incorporate this variability into land evaluation systems is proposed, using the land capability system for Scotland as a case study. L and capability classes were found to be sensitive to the climate reference period from which data are taken. Individual stations rarely occupy their l ong-term land capability class. In addition, the relative position of stati ons In the land classification alters from year to year, indicating variati ons with time in spatial correlation structures. Markov chain analysis was used in a risk assessment approach to estimate the mean return time to a la nd capability category for individual stations and for areas of land. The m ain conclusions were: that land evaluation systems should not be applied us ing data from a different period to the baseline weather period used to est ablish the classification; there is a need to establish whether groups of s tations tend to behave in similar ways over space and through time; mapping zones of risk could provide a means of formally incorporating weather vari ability into land evaluation. (C) 2000 Elsevier Science B.V. All rights res erved.