HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Abstract Full Text Free Full Text (PDF) Free Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in ISI Web of Science Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via ISI Web of Science (11) Citing Articles via Google Scholar Google Scholar Articles by Skaggs, T. H. Articles by Mohanty, B. P. Search for Related Content PubMed Articles by Skaggs, T. H. Articles by Mohanty, B. P. GeoRef GeoRef Citation Agricola Articles by Skaggs, T. H. Articles by Mohanty, B. P. Related Collections Structure and Properties Soil Physics Soil Methods/Instrumentation

Estimating Particle-Size Distribution from Limited Soil Texture Data

George E. Brown, Jr. Salinity Lab., 450 W. Big Springs Rd., Riverside, CA 92507

View larger version (17K): [in a new window]   Fig. 1. Particle-size classification system used in this study. The system differs from the USDA system only in that particle-size is expressed in terms of the particle radius (instead of diameter) and the units are micrometers (instead of mm).

View larger version (26K): [in a new window]   Fig. 2. The USDA soil texture classification system (top) and the range of soil textures covered in this study (bottom).

View larger version (26K): [in a new window]   Fig. 3. Estimated and fitted distributions for selected particle-size data. In each plot, the solid line is the estimate given by Eq. [4] and the dashed line is the fitted distribution P defined by Eq. [8]. The circles are the measured particle-size data, with the three filled circles in each plot corresponding to the values used as input in Eq. [4]: cl, cl + si, and cl + si + fvfs. Table 1 contains parameter and goodness-of-fit values for each plot. cl, clay fraction; fvfs, fine plus very fine sand fraction; si, silt fraction.

View larger version (27K): [in a new window]   Fig. 4. Histograms of the average absolute deviations AAD (top) and AADP (bottom).

View larger version (24K): [in a new window]   Fig. 5. Histograms of the maximum absolute deviations MAD (top) and MADP (bottom).

View larger version (37K): [in a new window]   Fig. 6. Illustration of the average absolute deviation (AAD) obtained for each soil. The size of a point is proportional to AAD, with the largest value being AAD = 12.8%. The plot demonstrates that was a poor estimate of the particle-size distribution whenever the silt mass fraction was greater than about 70%.

View larger version (20K): [in a new window]   Fig. 7. The data and model distributions from Fig. 3 replotted to illustrate the linear relationship that is indicated by Eq. [2]. In these plots data can be shown only for r > r0 and P(r) < 1. The two filled circles in each plot correspond to the cl + si and cl + si + fvfs values used as input in Eq. [4]. cl, clay fraction; fvfs, fine plus very fine sand fraction; si, silt fraction.