Raquel Stucchi Boschi

Software for micromorphometric characterization of soil pores obtained from 2-D image analysis

Studies of soil porosity through image analysis are important to an understanding of how the soil functions. However, the lack of a simplified methodology for the quantification of the shape, number, and size of soil pores has limited the use of information extracted from images. The present work proposes a software program for the quantification and characterization of soil porosity from data derived from 2-D images. The user-friendly software was developed in C++ and allows for the classification of pores in terms of size, shape, and combinations of size and shape. Using raw data generated by image analysis systems, the software calculates the following parameters for the characterization of soil porosity: total area of pore (Tap), number of pores, pore shape, pore shape and pore area, and pore shape and equivalent pore diameter (EqDiam). In this paper, the input file with the raw soil porosity data was generated using the Noesis Visilog 5.4 image analysis system; however other image analysis programs can be used, in which case, the input file requires a standard format to permit processing by this software. The software also shows the descriptive statistics (mean, standard deviation, variance, and the coefficient of variation) of the parameters considering the total number of images evaluated. The results show that the software is a complementary tool to any analysis of soil porosity, allowing for a precise and quick analysis.

Analysis of the Soil Sand Fraction and Recent Sediments Deposits: An Approach Based on Two-Dimensional Image Analysis

Abstract In this study, we propose a methodology (ImaGrain) for quantifying the sand fractions from two-dimensional images obtained from thin sections of undisturbed soil samples. Samples for this analysis were collected from soil horizons and sediment layers of two profiles and two pits, located in the Experimental Station of Tupi, Piracicaba, São Paulo, Brazil. Data from image analysis were used to calculate the mean, median, S.D. (a measure of sorting), skewness, and kurtosis of the size distribution of sand grains, and the results were compared with those obtained with the sieving (standard) method. Roundness of the sand grains was quantified with the ImaGrain method. The results showed that both methods classify the mean grain size as fine sand and that the values of S.D., skewness, and kurtosis for all samples were also similar. The sand grains of the sediment layers and soil horizons had similar degrees of sand grain roundness with a dominance of rounded and moderately rounded sand grains. Based on our results, ImaGrain should be explored further as a tool to quantify the soil sand fraction and for determining transport and deposition patterns. Image analysis also allows classifying the sand grain roundness, an important parameter that is not determined by the standard method.