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A Rapid Method of Analysis for Soil Macropore Structure: II. Stereological Model, Statistical Analysis, and Interpretation
Author(s) -
McBratney A. B.,
Moran C. J.
Publication year - 1990
Publication title -
soil science society of america journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.836
H-Index - 168
eISSN - 1435-0661
pISSN - 0361-5995
DOI - 10.2136/sssaj1990.03615995005400020037x
Subject(s) - macropore , smoothing , soil science , autocorrelation , tillage , mathematics , characterisation of pore space in soil , soil structure , porosity , geology , biological system , mineralogy , statistics , soil water , geotechnical engineering , chemistry , mesoporous material , biochemistry , catalysis , ecology , biology
A method for rapid analysis of soil macropore structure, much needed in tillage studies, is presented. The method does not attempt to quantitatively describe the soil pore structure fully. Rather, it is aimed at recognizing and measuring aspects of the pore space important for crop growth, especially for the detection or prediction of problems. The whole process can be completed in 3 d and provides a new level of spatial resolution for soil‐depth functions. Using digital binary images of vertical planes in the soil and assuming a vertically nonstatlonary, horizontally isotropic model for the pore geometry, estimates of several pore‐structure attributes are made using contiguous parallel linear probes. The attributes are porosity, surface area, and estimates of the average size of pore and solid, termed the pore star length and solid star length. Depth functions of these attributes are modeled statistically using Laplacian smoothing splines with allowance for autocorrelated errors. These depth functions provide a means of comparing pore geometry across soil types or between treatments. Data from a tillage trial are used to illustrate the technique. The data are also presented as generalized draftsman's displays, which illustrate treatment differences as well as suggest a possible method of grouping for use in further comparative studies. This relatively rapid method should allow soil scientists and agronomists to monitor detailed pore‐structure changes on a routine basis.