Naveed M.,University of Aarhus |
Moldrup P.,University of Aalborg |
Arthur E.,University of Aalborg |
Wildenschild D.,Oregon State University |
And 5 more authors.
Soil Science Society of America Journal | Year: 2013
The influence of clay content in soil-pore structure development and the relative importance of macroporosity in governing convective fluid flow are two key challenges toward better understanding and quantifying soil ecosystem functions. In this study, soil physical measurements (soil-water retention and air permeability) and x-ray computed tomography (CT) scanning were combined and used from two scales on intact soil columns (100 and 580 cm3). The columns were sampled along a natural clay gradient at six locations (L1, L2, L3, L4, L5 and L6 with 0.11, 0.16, 0.21, 0.32, 0.38 and 0.46 kg kg-1 clay content, respectively) at a field site in Lerbjerg, Denmark. The water-holding capacity of soils markedly increased with increasing soil clay content, while significantly higher air permeability was observed for the L1 to L3 soils than for the L4 to L6 soils. Higher air permeability values observed for 580- than 100-cm3 soil columns implied a scale effect and relatively greater importance of macropores in convective fluid flow at larger scale. Supporting this, x-ray CT showed that both interaggregate pores and biopores (pores formed by earthworms and plant roots) were present at L1 to L3 in decreasing order, whereas only interaggregate pores were observed at L4 to L6. Macroporosity inferred from x-ray CT to quantify pores >1 mm decreased from 2.9 to 0.1% from L1 to L6. A progressive improvement was observed in the linear relationship (R2 increasing 0.50-0.95) of air permeability with total air-filled porosity, CT-inferred macroporosity, and CT-inferred limiting macroporosity (minimum macroporosity for any quarter of soil column). The findings of this study show the immense potential in linking x-ray CT-derived soil-pore parameters with classical soil physical measurements for quantifying soil architecture and functions. Copyright © 2013 by the Soil Science Society of America, Inc.
Vogel H.-J.,Dep. of Soil Physics |
Clothier B.,Plant and Food Research |
Li X.-Y.,Beijing Normal University |
Lin H.S.,Pennsylvania State University
Vadose Zone Journal | Year: 2013
The guest editors provide an introduction for the Special Section: Frontiers of Hydropedology in Vadose Zone Research, introduce the 17 contributions, and discuss the role of hydropedology in today's vadose zone research. © Soil Science Society of America, All rights reserved.