Brief Summary of Minutes of Annual Meeting

Convened at Rocky Mountain Park Inn, Tuesday, August 2, 2011 Held in conjunction with NIFA Bouyoucos conference: Synchrotron characterization of airborne soil mineral and organic particulates originating from agriculturally modified ecosystems. Present: Bill Bland, Jim Harsh, Paul Bloom, Ray Knight, Stephen Anderson, Alvin Smuckers, Cliff Johnston, Dan Strawn Participant Reports All participants are asked to send a list of all activities related to project objectives to Jim Harsh to include in annual report. This includes papers, presentations, and service. Action Items Discussed coordinating an effort to inform soil science students of training opportunities and scholarships in application of advanced instrumentation to soils research. Discussed interest in conducting annual meeting in conjunction with other meetings, either multi-state or society meetings Discussed developing a symposium for the 2012 SSSA annual meetings Discussed developing a training workshop focused on soils and analytical capabilities. May be done in conjunction with another workshop, e.g., a summer synchrotron workshop. Ray mentioned there are opportunities for group members to participate in funded CAP grants. Group should inquire about participation at long-term research sites We need to increase participation, particularly early career professionals. USDA has higher education and challenge grants and the pre-doc fellowship programs that can be targeted for student funding. Next meeting will be will be at PNNL. Jim Harsh is coordinating. Election results are status quo: Chair-Jim Harsh, Vice-chair- , Secretary- Dan Strawn

Outputs: Publications 10/2010--09/2011 Aramrak, S., M. Flury, and J.B. Harsh. 2011. Detachment of Deposited Colloids by Advancing and Receding Air-Water Interfaces. Langmuir 27:9985-9993. Baker, L.L., D.G. Strawn, K.L. Vaughan, and P.A. McDaniel. 2010. XAS STUDY OF Fe MINERALOGY IN A CHRONOSEQUENCE OF SOIL CLAYS FORMED IN BASALTIC CINDERS. Clays and Clay Minerals 58:772-782. Baker, L.L., D.G. Strawn, W.C. Rember, and K.F. Sprenke. 2011. Metal content of charcoal in mining-impacted wetland sediments. Science of the Total Environment 409:588-594. Barrocas, P.R.G., W.M. Landing, and R.J.M. Hudson. 2010. Assessment of mercury(II) bioavailability using a bioluminescent bacterial biosensor: Practical and theoretical challenges. Journal of Environmental Sciences-China 22:1137-1143. Beak, D.G., J.K. Kirby, G.M. Hettiarachchi, L.A. Wendling, M.J. McLaughlin, and R. Khatiwada. 2011. Cobalt Distribution and Speciation: Effect of Aging, Intermittent Submergence, In Situ Rice Roots. Journal of Environmental Quality 40:679-695. Bedmar, F., P.E. Daniel, J.L. Costa, and D. Gimenez. 2011. SORPTION OF ACETOCHLOR, S-METOLACHLOR, AND ATRAZINE IN SURFACE AND SUBSURFACE SOIL HORIZONS OF ARGENTINA. Environmental Toxicology and Chemistry 30:1990-1996. de Livera, J., M.J. McLaughlin, D. Beak, G.M. Hettiarachchi, and J. Kirby. 2011a. Release of Dissolved Cadmium and Sulfur Nanoparticles from Oxidizing Sulfide Minerals. Soil Science Society of America Journal 75:842-854. de Livera, J., M.J. McLaughlin, G.M. Hettiarachchi, J.K. Kirby, and D.G. Beak. 2011b. Cadmium solubility in paddy soils: Effects of soil oxidation, metal sulfides and competitive ions. Science of the Total Environment 409:1489-1497. Gonzalez-Chavez, M.d.C.A., J.A. Aitkenhead-Peterson, T.J. Gentry, D. Zuberer, F. Hons, and R. Loeppert. 2010. Soil microbial community, C, N, and P responses to long-term tillage and crop rotation. Soil & Tillage Research 106:285-293. Guido, A.S., G.M. Hettiarachchi, C. Attanayake, P. Defoe, and M. Palomo. 2011. Bioavailability of lead in urban soil environments. Abstracts of Papers of the American Chemical Society 241. Han, T., Y. Nazarenko, P.J. Lioy, and G. Mainelis. 2011. Collection efficiencies of an electrostatic sampler with superhydrophobic surface for fungal bioaerosols. Indoor Air 21:110-120. Hass, A., R.H. Loeppert, M.G. Messina, and T.D. Rogers. 2011. Determination of Phosphate in Selective Extractions for Soil Iron Oxides by the Molybdenum Blue Method in an Automated Continuance Flow Injection System. Communications in Soil Science and Plant Analysis 42:1619-1635. Kang, D.-H., S.C. Gupta, P.R. Bloom, A.Z. Ranaivoson, R. Roberson, and J. Siekmeier. 2011. Recycled Materials as Substitutes for Virgin Aggregates in Road Construction: II. Inorganic Contaminant Leaching. Soil Science Society of America Journal 75:1276-1284. Kaufhold, S., R. Dohrmann, J.W. Stucki, and A.S. Anastacio. 2011. LAYER CHARGE DENSITY OF SMECTITES - CLOSING THE GAP BETWEEN THE STRUCTURAL FORMULA METHOD AND THE ALKYL AMMONIUM METHOD. Clays and Clay Minerals 59:200-211. Kaufhold, S., K. Ufer, A. Kaufhold, J.W. Stucki, A.S. Anastacio, R. Jahn, and R. Dohrmann. 2010. QUANTIFICATION OF ALLOPHANE FROM ECUADOR. Clays and Clay Minerals 58:707-716. Khaokaew, S., R.L. Chaney, G. Landrot, M. Ginder-Vogel, and D.L. Sparks. 2011. Speciation and Release Kinetics of Cadmium in an Alkaline Paddy Soil under Various Flooding Periods and Draining Conditions. Environmental Science & Technology 45:4249-4255. Kim, H., S.H. Anderson, P.P. Motavalli, and C.J. Gantzer. 2010. Compaction effects on soil macropore geometry and related parameters for an arable field. Geoderma 160:244-251. Kravchenko, A., R.E. Falconer, D. Grinev, and W. Otten. 2011a. Fungal colonization in soils with different management histories: modeling growth in three-dimensional pore volumes. Ecological Applications 21:1202-1210. Kravchenko, A.N., A.N.W. Wang, A.J.M. Smucker, and M.L. Rivers. 2011b. Long-term Differences in Tillage and Land Use Affect Intra-aggregate Pore Heterogeneity. Soil Science Society of America Journal 75:1658-1666. Kravchenko, A.N., A.N.W. Wang, A.J.M. Smucker, and M.L. Rivers. 2011c. Long-term Differences in Tillage and Land Use Affect Intra-aggregate Pore Heterogeneity. Soil Science Society of America Journal 75:1658-1666. Kumar, S., R.P. Udawatta, and S.H. Anderson. 2010. Root length density and carbon content of agroforestry and grass buffers under grazed pasture systems in a Hapludalf. Agroforestry Systems 80:85-96. Kwon, H.-Y., and R.J.M. Hudson. 2010. Quantifying management-driven changes in organic matter turnover in an agricultural soil: An inverse modeling approach using historical data and a surrogate CENTURY-type model. Soil Biology & Biochemistry 42:2241-2253. Lafferty, B.J., M. Ginder-Vogel, and D.L. Sparks. 2010a. Arsenite Oxidation by a Poorly Crystalline Manganese-Oxide 1. Stirred-Flow Experiments. Environmental Science & Technology 44:8460-8466. Lafferty, B.J., M. Ginder-Vogel, M. Zhu, K.J.T. Livi, and D.L. Sparks. 2010b. Arsenite Oxidation by a Poorly Crystalline Manganese-Oxide. 2. Results from X-ray Absorption Spectroscopy and X-ray Diffraction. Environmental Science & Technology 44:8467-8472. Lee, S.S., C.J. Gantzer, A.L. Thompson, and S.H. Anderson. 2011. Polyacrylamide efficacy for reducing soil erosion and runoff as influenced by slope. (in English) Journal of Soil and Water Conservation 66:172-177. Li, T., Z. Di, X. Yang, and D.L. Sparks. 2011. Effects of dissolved organic matter from the rhizosphere of the hyperaccumulator Sedum alfredii on sorption of zinc and cadmium by different soils. Journal of Hazardous Materials 192:1616-1622. Lombi, E., G.M. Hettiarachchi, and K.G. Scheckel. 2011. Advanced in situ Spectroscopic Techniques and Their Applications in Environmental Biogeochemistry: Introduction to the Special Section. Journal of Environmental Quality 40:659-666. Masue-Slowey, Y., R.H. Loeppert, and S. Fendorf. 2011. Alteration of ferrihydrite reductive dissolution and transformation by adsorbed As and structural Al: Implications for As retention. Geochimica Et Cosmochimica Acta 75:870-886. Munoz, J.D., and A. Kravchenko. 2011. Soil carbon mapping using on-the-go near infrared spectroscopy, topography and aerial photographs. Geoderma 166:102-110. Nazarenko, Y., T.W. Han, P.J. Lioy, and G. Mainelis. 2011. Potential for exposure to engineered nanoparticles from nanotechnology-based consumer spray products. Journal of Exposure Science and Environmental Epidemiology 21:515-528. Oram, L.L., D.G. Strawn, and G. Moeller. 2011. Chemical Speciation and Bioavailability of Selenium in the Rhizosphere of Symphyotrichum eatonii from Reclaimed Mine Soils. Environmental Science & Technology 45:870-875. Parikh, S.J., J.D. Kubicki, C.M. Jonsson, C.L. Jonsson, R.M. Hazen, D.A. Sverjensky, and D.L. Sparks. 2011. Evaluating Glutamate and Aspartate Binding Mechanisms to Rutile (alpha-TiO2) via ATR-FTIR Spectroscopy and Quantum Chemical Calculations. Langmuir 27:1778-1787. Paudel, B.R., R.P. Udawatta, and S.H. Anderson. 2011. Agroforestry and grass buffer effects on soil quality parameters for grazed pasture and row-crop systems. Applied Soil Ecology 48:125-132. Pereira, M.C., L.C.D. Cavalcante, F. Magalhaes, J.D. Fabris, J.W. Stucki, L.C.A. Oliveira, and E. Murad. 2011. Composites prepared from natural iron oxides and sucrose: A highly reactive system for the oxidation of organic contaminants in water. Chemical Engineering Journal 166:962-969. Shalat, S.L., A.A. Stambler, Z. Wang, G. Mainelis, O.H. Emoekpere, M. Hernandez, P.J. Lioy, and K. Black. 2011. Development and In-Home Testing of the Pretoddler Inhalable Particulate Environmental Robotic (PIPER Mk IV) Sampler. Environmental Science & Technology 45:2945-2950. Shimizu, M., Y. Arai, and D.L. Sparks. 2011. Multiscale Assessment of Methylarsenic Reactivity in Soil. 1. Sorption and Desorption on Soils. Environmental Science & Technology 45:4293-4299. Somenahally, A.C., E.B. Hollister, R.H. Loeppert, W. Yan, and T.J. Gentry. 2011. Microbial communities in rice rhizosphere altered by intermittent and continuous flooding in fields with long-term arsenic application. Soil Biology & Biochemistry 43:1220-1228. Son, E.K., V. Krumins, B.J. Schwab, G. Mainelis, and D.E. Fennell. 2009. Monitoring Growth and Activity of Bacteria in Air. Abstracts of the General Meeting of the American Society for Microbiology 109. Stucki, J.W. 2011. A review of the effects of iron redox cycles on smectite properties. Comptes Rendus Geoscience 343:199-209. Tamir, G., M. Shenker, H. Heller, P.R. Bloom, P. Fine, and A. Bar-Tal. 2011. Can Soil Carbonate Dissolution Lead to Overestimation of Soil Respiration? Soil Science Society of America Journal 75:1414-1422. Udawatta, R.P., S.H. Anderson, P.P. Motavalli, and H.E. Garrett. 2011. Calibration of a water content reflectometer and soil water dynamics for an agroforestry practice. Agroforestry Systems 82:61-75. Urbanek, E., A.J.M. Smucker, and R. Horn. 2011. Total and fresh organic carbon distribution in aggregate size classes and single aggregate regions using natural C-13/C-12 tracer. Geoderma 164:164-171. Wang, W., A.N. Kravchenko, A.J.M. Smucker, and M.L. Rivers. 2011a. Comparison of image segmentation methods in simulated 2D and 3D microtomographic images of soil aggregates. Geoderma 162:231-241. Wang, W., A.N. Kravchenko, A.J.M. Smucker, and M.L. Rivers. 2011b. Comparison of image segmentation methods in simulated 2D and 3D microtomographic images of soil aggregates. Geoderma 162:231-241. Activities: In August, 2011, in association with our annual meeting, Alvin Smucker and other NC-1187 members (Bloom, Harsh, Strawn, Anderson) held a Bouyoucos Conference on "Synchrotron Characterization of Soil Mineral Surfaces, Organic and Inorganic Particulates and Pores in Agricultural Soils and other Modified Ecosystems" The primary focus of this conference was to explore the expanded use of synchrotron spectromicroscopy and other techniques in the atmospheric and soil sciences to better assist scientists, and state and federal regulators who are struggling to understand and regulate soil biological, chemical and physical transformations of particulate emissions from agricultural and forest ecosystems and range lands. New applications of emerging micro-scale synchrotron analytical approaches for characterizing these interactions occurring among airborne soil particulates were proposed and discussed by a diverse group of Conference participants. Leading scientists from field including soil mineralogy/chemistry, atmospheric modeling, x-ray microtomography, x-ray spectromicroscopy, and global modeling gave keynote talks to bring attendees up to date on the current state of both large scale modeling and spectroscopic techniques. Attendees presented posters of their current work. Breakout sessions were conducted outline potential collaborations for request for proposals coming out from NIFA and other funding agencies. Milestones: The Bouyoucos Conference was held. The working proposal group has not yet been formed.

Aramrak, S., M. Flury, and J.B. Harsh. 2011. Detachment of Deposited Colloids by Advancing and Receding Air-Water Interfaces. Langmuir 27:9985-9993. Baker, L.L., D.G. Strawn, K.L. Vaughan, and P.A. McDaniel. 2010. XAS STUDY OF Fe MINERALOGY IN A CHRONOSEQUENCE OF SOIL CLAYS FORMED IN BASALTIC CINDERS. Clays and Clay Minerals 58:772-782. Baker, L.L., D.G. Strawn, W.C. Rember, and K.F. Sprenke. 2011. Metal content of charcoal in mining-impacted wetland sediments. Science of the Total Environment 409:588-594. Barrocas, P.R.G., W.M. Landing, and R.J.M. Hudson. 2010. Assessment of mercury(II) bioavailability using a bioluminescent bacterial biosensor: Practical and theoretical challenges. Journal of Environmental Sciences-China 22:1137-1143. Beak, D.G., J.K. Kirby, G.M. Hettiarachchi, L.A. Wendling, M.J. McLaughlin, and R. Khatiwada. 2011. Cobalt Distribution and Speciation: Effect of Aging, Intermittent Submergence, In Situ Rice Roots. Journal of Environmental Quality 40:679-695. Bedmar, F., P.E. Daniel, J.L. Costa, and D. Gimenez. 2011. SORPTION OF ACETOCHLOR, S-METOLACHLOR, AND ATRAZINE IN SURFACE AND SUBSURFACE SOIL HORIZONS OF ARGENTINA. Environmental Toxicology and Chemistry 30:1990-1996. de Livera, J., M.J. McLaughlin, D. Beak, G.M. Hettiarachchi, and J. Kirby. 2011a. Release of Dissolved Cadmium and Sulfur Nanoparticles from Oxidizing Sulfide Minerals. Soil Science Society of America Journal 75:842-854. de Livera, J., M.J. McLaughlin, G.M. Hettiarachchi, J.K. Kirby, and D.G. Beak. 2011b. Cadmium solubility in paddy soils: Effects of soil oxidation, metal sulfides and competitive ions. Science of the Total Environment 409:1489-1497. Gonzalez-Chavez, M.d.C.A., J.A. Aitkenhead-Peterson, T.J. Gentry, D. Zuberer, F. Hons, and R. Loeppert. 2010. Soil microbial community, C, N, and P responses to long-term tillage and crop rotation. Soil & Tillage Research 106:285-293. Guido, A.S., G.M. Hettiarachchi, C. Attanayake, P. Defoe, and M. Palomo. 2011. Bioavailability of lead in urban soil environments. Abstracts of Papers of the American Chemical Society 241. Han, T., Y. Nazarenko, P.J. Lioy, and G. Mainelis. 2011. Collection efficiencies of an electrostatic sampler with superhydrophobic surface for fungal bioaerosols. Indoor Air 21:110-120. Hass, A., R.H. Loeppert, M.G. Messina, and T.D. Rogers. 2011. Determination of Phosphate in Selective Extractions for Soil Iron Oxides by the Molybdenum Blue Method in an Automated Continuance Flow Injection System. Communications in Soil Science and Plant Analysis 42:1619-1635. Kang, D.-H., S.C. Gupta, P.R. Bloom, A.Z. Ranaivoson, R. Roberson, and J. Siekmeier. 2011. Recycled Materials as Substitutes for Virgin Aggregates in Road Construction: II. Inorganic Contaminant Leaching. Soil Science Society of America Journal 75:1276-1284. Kaufhold, S., R. Dohrmann, J.W. Stucki, and A.S. Anastacio. 2011. LAYER CHARGE DENSITY OF SMECTITES - CLOSING THE GAP BETWEEN THE STRUCTURAL FORMULA METHOD AND THE ALKYL AMMONIUM METHOD. Clays and Clay Minerals 59:200-211. Kaufhold, S., K. Ufer, A. Kaufhold, J.W. Stucki, A.S. Anastacio, R. Jahn, and R. Dohrmann. 2010. QUANTIFICATION OF ALLOPHANE FROM ECUADOR. Clays and Clay Minerals 58:707-716. Khaokaew, S., R.L. Chaney, G. Landrot, M. Ginder-Vogel, and D.L. Sparks. 2011. Speciation and Release Kinetics of Cadmium in an Alkaline Paddy Soil under Various Flooding Periods and Draining Conditions. Environmental Science & Technology 45:4249-4255. Kim, H., S.H. Anderson, P.P. Motavalli, and C.J. Gantzer. 2010. Compaction effects on soil macropore geometry and related parameters for an arable field. Geoderma 160:244-251. Kravchenko, A., R.E. Falconer, D. Grinev, and W. Otten. 2011a. Fungal colonization in soils with different management histories: modeling growth in three-dimensional pore volumes. Ecological Applications 21:1202-1210. Kravchenko, A.N., A.N.W. Wang, A.J.M. Smucker, and M.L. Rivers. 2011b. Long-term Differences in Tillage and Land Use Affect Intra-aggregate Pore Heterogeneity. Soil Science Society of America Journal 75:1658-1666. Kravchenko, A.N., A.N.W. Wang, A.J.M. Smucker, and M.L. Rivers. 2011c. Long-term Differences in Tillage and Land Use Affect Intra-aggregate Pore Heterogeneity. Soil Science Society of America Journal 75:1658-1666. Kumar, S., R.P. Udawatta, and S.H. Anderson. 2010. Root length density and carbon content of agroforestry and grass buffers under grazed pasture systems in a Hapludalf. Agroforestry Systems 80:85-96. Kwon, H.-Y., and R.J.M. Hudson. 2010. Quantifying management-driven changes in organic matter turnover in an agricultural soil: An inverse modeling approach using historical data and a surrogate CENTURY-type model. Soil Biology & Biochemistry 42:2241-2253. Lafferty, B.J., M. Ginder-Vogel, and D.L. Sparks. 2010a. Arsenite Oxidation by a Poorly Crystalline Manganese-Oxide 1. Stirred-Flow Experiments. Environmental Science & Technology 44:8460-8466. Lafferty, B.J., M. Ginder-Vogel, M. Zhu, K.J.T. Livi, and D.L. Sparks. 2010b. Arsenite Oxidation by a Poorly Crystalline Manganese-Oxide. 2. Results from X-ray Absorption Spectroscopy and X-ray Diffraction. Environmental Science & Technology 44:8467-8472. Lee, S.S., C.J. Gantzer, A.L. Thompson, and S.H. Anderson. 2011. Polyacrylamide efficacy for reducing soil erosion and runoff as influenced by slope. (in English) Journal of Soil and Water Conservation 66:172-177. Li, T., Z. Di, X. Yang, and D.L. Sparks. 2011. Effects of dissolved organic matter from the rhizosphere of the hyperaccumulator Sedum alfredii on sorption of zinc and cadmium by different soils. Journal of Hazardous Materials 192:1616-1622. Lombi, E., G.M. Hettiarachchi, and K.G. Scheckel. 2011. Advanced in situ Spectroscopic Techniques and Their Applications in Environmental Biogeochemistry: Introduction to the Special Section. Journal of Environmental Quality 40:659-666. Masue-Slowey, Y., R.H. Loeppert, and S. Fendorf. 2011. Alteration of ferrihydrite reductive dissolution and transformation by adsorbed As and structural Al: Implications for As retention. Geochimica Et Cosmochimica Acta 75:870-886. Munoz, J.D., and A. Kravchenko. 2011. Soil carbon mapping using on-the-go near infrared spectroscopy, topography and aerial photographs. Geoderma 166:102-110. Nazarenko, Y., T.W. Han, P.J. Lioy, and G. Mainelis. 2011. Potential for exposure to engineered nanoparticles from nanotechnology-based consumer spray products. Journal of Exposure Science and Environmental Epidemiology 21:515-528. Oram, L.L., D.G. Strawn, and G. Moeller. 2011. Chemical Speciation and Bioavailability of Selenium in the Rhizosphere of Symphyotrichum eatonii from Reclaimed Mine Soils. Environmental Science & Technology 45:870-875. Parikh, S.J., J.D. Kubicki, C.M. Jonsson, C.L. Jonsson, R.M. Hazen, D.A. Sverjensky, and D.L. Sparks. 2011. Evaluating Glutamate and Aspartate Binding Mechanisms to Rutile (alpha-TiO2) via ATR-FTIR Spectroscopy and Quantum Chemical Calculations. Langmuir 27:1778-1787. Paudel, B.R., R.P. Udawatta, and S.H. Anderson. 2011. Agroforestry and grass buffer effects on soil quality parameters for grazed pasture and row-crop systems. Applied Soil Ecology 48:125-132. Pereira, M.C., L.C.D. Cavalcante, F. Magalhaes, J.D. Fabris, J.W. Stucki, L.C.A. Oliveira, and E. Murad. 2011. Composites prepared from natural iron oxides and sucrose: A highly reactive system for the oxidation of organic contaminants in water. Chemical Engineering Journal 166:962-969. Shalat, S.L., A.A. Stambler, Z. Wang, G. Mainelis, O.H. Emoekpere, M. Hernandez, P.J. Lioy, and K. Black. 2011. Development and In-Home Testing of the Pretoddler Inhalable Particulate Environmental Robotic (PIPER Mk IV) Sampler. Environmental Science & Technology 45:2945-2950. Shimizu, M., Y. Arai, and D.L. Sparks. 2011. Multiscale Assessment of Methylarsenic Reactivity in Soil. 1. Sorption and Desorption on Soils. Environmental Science & Technology 45:4293-4299. Somenahally, A.C., E.B. Hollister, R.H. Loeppert, W. Yan, and T.J. Gentry. 2011. Microbial communities in rice rhizosphere altered by intermittent and continuous flooding in fields with long-term arsenic application. Soil Biology & Biochemistry 43:1220-1228. Son, E.K., V. Krumins, B.J. Schwab, G. Mainelis, and D.E. Fennell. 2009. Monitoring Growth and Activity of Bacteria in Air. Abstracts of the General Meeting of the American Society for Microbiology 109. Stucki, J.W. 2011. A review of the effects of iron redox cycles on smectite properties. Comptes Rendus Geoscience 343:199-209. Tamir, G., M. Shenker, H. Heller, P.R. Bloom, P. Fine, and A. Bar-Tal. 2011. Can Soil Carbonate Dissolution Lead to Overestimation of Soil Respiration? Soil Science Society of America Journal 75:1414-1422. Udawatta, R.P., S.H. Anderson, P.P. Motavalli, and H.E. Garrett. 2011. Calibration of a water content reflectometer and soil water dynamics for an agroforestry practice. Agroforestry Systems 82:61-75. Urbanek, E., A.J.M. Smucker, and R. Horn. 2011. Total and fresh organic carbon distribution in aggregate size classes and single aggregate regions using natural C-13/C-12 tracer. Geoderma 164:164-171. Wang, W., A.N. Kravchenko, A.J.M. Smucker, and M.L. Rivers. 2011a. Comparison of image segmentation methods in simulated 2D and 3D microtomographic images of soil aggregates. Geoderma 162:231-241. Wang, W., A.N. Kravchenko, A.J.M. Smucker, and M.L. Rivers. 2011b. Comparison of image segmentation methods in simulated 2D and 3D microtomographic images of soil aggregates. Geoderma 162:231-241.