Pattern analysis of a grazing experiment

Abstract

The complementary functions of pattern analysis and statistical analysis are discussed, with particular reference to the analysis of agricultural experiments. It is suggested that pattern analysis, in addition to its usual function of simplification of complex data, may contribute to the analysis of grazing experiments in the special case in which there is reason to suspect the existence of an external non-random environmental factor. Such a case is analysed completely; it is shown that the existence of such a factor can be established by intrinsic classification of entire liveweight sequences. The factor can then be partitioned out by principal coordinate analysis; its spatial configuration can be elucidated, and the extent of its contribution to the overall results assessed. Its optimum correlation with parallel botanical data can be established by canonical coordinate analysis. It is then possible to formulate causative hypotheses as to the nature of the factor; in the present case the most plausible hypothesis was that a small systematic change in tree density caused a progressive reduction in quantity and quality of herbage as we passed from the centre of the area to the periphery. This hypothesis could be used for further experiment and statistical test. Standard programmes for the entire analysis exist on the Control Data 3600 computer at Canberra.