VARIABILITY OF ORGANIC-MATTER AND EXCHANGEABLE CATIONS WITHIN THE A-2 HORIZON OF AN IRON PODZOL

Analysis of variance has been carried out between soil samples separated by distances of 0.5 m, 10 m and 0.5–8 km. The samples were taken from the A2 horizon of the Countesswells series iron podzol, thus maintaining the same pedological feature, profile class and parent material. The organic matter has been examined by the pyrolysis characteristics, total carbon and nitrogen, and the cations by exchangeable Ca2+, Mg2+, Na+, K+ and H+, whilst pH and total phosphorus have also been determined. The analysis of variance with respect to distance between the samples shows that all the properties examined exhibit considerable variation over short distances, many showing the major proportion of their total variance at a distance of 0.5 m. This markedly limits the interpretation of data from single samples. Those properties reflecting base status and humus type show, in addition, a variation of similar size over distances of the order of a kilometre. Copyright © 1979, Wiley Blackwell. All rights reserved