Anais do XXXV Congresso Brasileiro de Ciência do Solo
QUANTIFYING THE INFLUENCE OF TILLAGE SYSTEM ON SOIL STRUCTURAL QUALITY USING X-RAY COMPUTED TOMOGRAPHY
MILA MARIC(1); RICHARD JOHN HECK(1); WILLIAM DEEN(1); 1 - UNIVERSITY OF GUELPH;
This research was focused on quantifying the impact of tillage systems on the annual dynamics of soil microstructure. Intact soil cores were collected from long-term management plots in Ontario, Canada. Specific attention was given to zero-tillage, spring plow and spring tandem disk systems. X-ray CT scanning was used to obtain high-resolution 3D imagery of each core. Analysis of the Hounsfield-scale imagery revealed higher radio-densities for the whole soil and soil matrix in the zero-till plots, at post-planting. This corresponded with notably less soil porosity. Specialized plugins were used in ImageJ to segment resolvable pores, then to quantify their abundance and morphology in the binarized imagery. The dominant pore shapes were triaxial and prolate, with equant and oblate usually being present in lesser amounts. Changes in pore shape, during the growing season, could be explained by root extension and faunal activity, as well as drying and wetting. During the winter, the tendency to increase triaxial pores, could be related to the formation of ice lenses. Though there was a convergence of pore size distribution, in the tilled and zero-till soils, and both spring tillage systems increased the proportion of smaller pores, the spring-plowed soils showed the greatest increase in pore size over the winter. Considering interim results, in comparison with zero-till, spring tillage systems (especially plowing), not only directly altered soil structure, but also its response to natural factors during both the growing and winter seasons.
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