VARIABILITY IN THREE AREAS OF THE DENCHWORTH SOIL MAP UNIT

Summary This paper shows correlations between soil properties and uses multivariate techniques to investigate similarities between profiles in relation to substrata. It compares laboratory measurements and field observations as means of characterizing soils. Correlations between two pH measurements and between fine clay and clay are large at all depths. Linear regressions indicate that close prediction of pH in water and fine clay content is possible from pH in CaCl 2 , and clay content respectively. Prediction of organic matter content from matrix Munsell colour value seems reliable within this limited range of soils. Field observation of carbonates correlates well with the laboratory measurement. Some indication of iron oxide content is given by matrix chroma. Significance of observed horizonation is confirmed by two minimum spanning trees, based on field observations and on laboratory measurements, which each link the samples in a similar way. Mean similarities between depths show that depths 2 and 3 are most alike. Inclusion of profiles on three different geological substrata under one series name is justified by the within‐ and between‐substrata similarities being alike, although profiles from each are not mixed at random. Plots of the profiles relative to the axes obtained by principal coordinates analysis of laboratory measurements and field observations show remarkable agreement. Rotational fitting of these plots indicates little difference between the three substrata.