Craig Rasmussen

Interests

Teaching

I teach classes in Soil Science, including Soil Genesis, Morphology and Classification, and a graduate level course in Pedogenesis.

Research

The Environmental Pedology Group focuses on soil forming processes and the importance of soils in ecosystem function and biogeochemical cycles. Our research and teaching program spans a broad range of topics including: i) organic and inorganic carbon cycling, with a focus on mineral weathering processes and the interaction of organic materials with mineral surfaces; ii) soil development control of soil-water dynamics and ecosystem response to climate change; iii) digital soil mapping and soil-landscape classification; and iv) energy-based modeling of pedogenesis and ecosystem function.

Courses

Scholarly Contributions

Chapters

• Heckman, K., & Rasmussen, C. (2018). Role of Mineralogy and Climate in the Soil Carbon Cycle. In Developments in Soil Science(pp 93--110). Elsevier.
• Volkmann, T., Sengupta, A., Pangle, L. A., Dontsova, K., Barron-Gafford, G. A., Harman, C. J., Niu, G., Meredith, L. K., Abramson, N., Neto, A., Wang, Y., Adams, J. R., Breshears, D. D., Bugaj, A., Chorover, J., Cueva, A., DeLong, S. B., Durcik, M., Ferre, T., , Hunt, E. A., et al. (2018). Controlled Experiments of Hillslope Coevolution at the Biosphere 2 Landscape Evolution Observatory: Toward Prediction of Coupled Hydrological, Biogeochemical, and Ecological Change. In Hydrology of Artificial and Controlled Experiments. IntechOpen.
• Rasmussen, C., Lybrand, R. A., Orem, C., Kielhofer, J., & Holleran, M. (2017). Soils of the Western Range and Irrigated Land Resource Region: LRR D. In The Soils of the USA(pp 115--130). Springer International Publishing.
• Rasmussen, C., Lybrand, R., Holleran, M., Orem, C., & Kielhofer, J. (2016). Soils of the western irrigated and range region. In Soils of the USA.

Journals/Publications

• Billings, S. A., Lajtha, K., Malhotra, A., Berhe, A. A., Graaff, M., Earl, S., Fraterrigo, J., Georgiou, K., Grandy, S., Hobbie, S. E., & others, . (2021). Soil organic carbon is not just for soil scientists: measurement recommendations for diverse practitioners. Ecological Applications, 31(3), e02290.
• Fehmi, J. S., Rasmussen, C., & Arnold, A. E. (2021). The pioneer effect advantage in plant invasions: site priming of native grasslands by invasive grasses. Ecosphere, 12(9), e03750.
• Finley, B. K., Mau, R. L., Hayer, M., Stone, B. W., Morrissey, E. M., Koch, B. J., Rasmussen, C., Dijkstra, P., Schwartz, E., & Hungate, B. A. (2021). Soil minerals affect taxon-specific bacterial growth. The ISME journal, 1--9.
• Heckman, K. A., Nave, L. E., Bowman, M., Gallo, A., Hatten, J. A., Matosziuk, L. M., Possinger, A. R., SanClements, M., Strahm, B. D., Weiglein, T. L., & others, . (2021). Divergent controls on carbon concentration and persistence between forests and grasslands of the conterminous US. Biogeochemistry, 156(1), 41--56.
• Heckman, K., Hicks, P., Lawrence, C. R., Rasmussen, C., Crow, S. E., Hoyt, A. M., Fromm, S. F., Shi, Z., Stoner, S., McGrath, C., & others, . (2021). Beyond bulk: Density fractions explain heterogeneity in global soil carbon abundance and persistence. Global change biology.
• McGuire, L. A., Rasmussen, C., Youberg, A. M., Sanderman, J., & Fenerty, B. (2021). Controls on the Spatial Distribution of Near-Surface Pyrogenic Carbon on Hillslopes 1 Year Following Wildfire. Journal of Geophysical Research: Earth Surface, 126(6), e2020JF005996.
• Tau, G., Crouvi, O., Enzel, Y., Teutsch, N., Ginoux, P., & Rasmussen, C. (2021). Shutting down dust emission during the middle Holocene drought in the Sonoran Desert, Arizona, USA. Geology.
• Wieder, W. R., Pierson, D., Earl, S., Lajtha, K., Baer, S. G., Ballantyne, F., Berhe, A. A., Billings, S. A., Brigham, L. M., Chacon, S. S., & others, . (2021). SoDaH: the SOils DAta Harmonization database, an open-source synthesis of soil data from research networks, version 1.0. Earth System Science Data, 13(5), 1843--1854.
• Zhang, S., Liu, G., Chen, S., Rasmussen, C., & Liu, B. (2021). Assessing soil thickness in a black soil watershed in northeast China using random forest and field observations. International Soil and Water Conservation Research, 9(1), 49--57.
• Billings, S. A., Lajtha, K., Malhotra, A., Berhe, A. A., Graaff, M., Earl, S., Fraterrigo, J., Georgiou, K., Grandy, S., Hobbie, S. E., & others, . (2020). Soil organic carbon is not just for soil scientists: measurement recommendations for diverse practitioners. Ecological Applications, e2290.
• Espinosa, N. J., Moore, D. J., Rasmussen, C., Fehmi, J. S., & Gallery, R. E. (2020). Woodchip and biochar amendments differentially influence microbial responses, but do not enhance plant recovery in disturbed semiarid soils. Restoration Ecology, 28, S381--S392.
• Fairbanks, D., Shepard, C., Murphy, M., Rasmussen, C., Chorover, J., Rich, V., & Gallery, R. (2020). Depth and topographic controls on microbial activity in a recently burned sub-alpine catchment. Soil Biology and Biochemistry, 107844.
• Fehmi, J. S., Rasmussen, C., & Gallery, R. E. (2020). Biochar and woodchip amendments alter restoration outcomes, microbial processes, and soil moisture in a simulated semi-arid ecosystem. Restoration Ecology, 28, S355--S364.
• Heckman, K. A., Nave, L. E., Bowman, M., Gallo, A., Hatten, J. A., Matosziuk, L. M., Possinger, A. R., SanClements, M., Strahm, B. D., Weiglein, T. L., & others, . (2020). Divergent controls on carbon concentration and persistence between forests and grasslands of the conterminous US. Biogeochemistry, 1--16.
• Lawrence, C. R., Beem-Miller, J., Hoyt, A. M., Monroe, G., Sierra, C. A., Stoner, S., Heckman, K., Blankinship, J. C., Crow, S. E., McNicol, G., & others, . (2020). An open-source database for the synthesis of soil radiocarbon data: International Soil Radiocarbon Database (ISRaD) version 1.0. Earth System Science Data, 12(1), 61--76.
• Levi, E. M., Archer SR, ., Throop, H. L., & Rasmussen, C. (2020). Soil-litter mixing promotes decomposition and soil aggregate formation on contrasting geomorphic surfaces in a shrub-invaded Sonoran Desert grassland. Plant and Soil, 450(1), 397--415.
• Moravec, B. G., White, A. M., Root, R. A., Sanchez, A., Olshansky, Y., Paras, B. K., Carr, B., McIntosh, J., Pelletier, J. D., Rasmussen, C., & others, . (2020). Resolving deep critical zone architecture in complex volcanic terrain. Journal of Geophysical Research: Earth Surface, 125(1), e2019JF005189.
• Wieder, W. R., Pierson, D., Earl, S., Lajtha, K., Baer, S., Ballantyne, F., Berhe, A. A., Billings, S., Brigham, L. M., Chacon, S. S., & others, . (2020). SoDaH: the SOils DAta Harmonization database, an open-source synthesis of soil data from research networks, version 1.0. Earth System Science Data Discussions, 1--19.
• Kobayashi, T., Rasmussen, C., & Sumida, H. (2019). Characterization of the perylenequinone pigments in Japanese Andosols and Cambisol. Soil science and plant nutrition, 65(1), 1--10.
• Lawrence, C., Beem-Miller, J., Hoyt, A., Monroe, G., Sierra, C., Stoner, S., Heckman, K., Blankinship, J., Crow, S., McNicol, G., Trumbore, S., Levine, P., Vinduskova, O., Todd-Brown, K., Rasmussen, C., Hicks Pries, C., Schadel, C., McFarlane, K., Doetterl, S., & Hatte, C. (2020). An open-source database for the synthesis of soil radiocarbon data: International Soil Radiocarbon Database (ISRaD) version 1.0. EARTH SYSTEM SCIENCE DATA, 12, 61-76.
• Moravec, B. G., White, A. M., Root, R., Sanchez, A., Olshansky, Y., Paras, B. K., Carr, B., McIntosh, J., Pelletier, J. D., Rasmussen, C., & others, . (2019). Resolving deep critical zone architecture in complex volcanic terrain. Journal of Geophysical Research: Earth Surface, e2019JF005189.
• Olshansky, Y., Knowles, J. F., Barron-Gafford, G. A., Rasmussen, C., Abramson, N., & Chorover, J. (2019). Soil fluid biogeochemical response to climatic events. Journal of Geophysical Research: Biogeosciences, 124(9), 2866--2882.
• Rasmussen, C. (2019). A new geological slip rate estimate for the Calico Fault, eastern California: implications for geodetic versus geologic rate estimates in the Eastern California Shear Zone. International Geology Review.
• Rasmussen, C. (2019). Soil Fluid Biogeochemical Response to Climatic Events. Journal of Geophysical Research: Biogeosciences.
• Regmi, N. R., McDonald, E. V., & Rasmussen, C. (2019). Hillslope response under variable microclimate. Earth Surface Processes and Landforms, 44(13), 2615--2627.
• Xie, S., Gallant, E., Wetmore, P. H., Figueiredo, P. M., Owen, L. A., Rasmussen, C., Malservisi, R., & Dixon, T. H. (2019). A new geological slip rate estimate for the Calico Fault, eastern California: implications for geodetic versus geologic rate estimates in the Eastern California Shear Zone. International Geology Review, 61(13), 1613--1641.
• Blankinship, J. C., Berhe, A. A., Crow, S. E., Druhan, J. L., Heckman, K. A., Keiluweit, M., Lawrence, C. R., Mar'in-Spiotta, E., Plante, A. F., Rasmussen, C., & others, . (2018). Improving understanding of soil organic matter dynamics by triangulating theories, measurements, and models. Biogeochemistry, 140(1), 1--13.
• Chang, L., Dwivedi, R., Knowles, J. F., Fang, Y., Niu, G., Pelletier, J. D., Rasmussen, C., Durcik, M., Barron-Gafford, G. A., & Meixner, T. (2018). Why Do Large-Scale Land Surface Models Produce a Low Ratio of Transpiration to Evapotranspiration?. Journal of Geophysical Research: Atmospheres, 123(17), 9109--9130.
• Finley, B. K., Dijkstra, P., Rasmussen, C., Schwartz, E., Mau, R. L., Liu, X. A., Van, G. N., & Hungate, B. A. (2018). Soil mineral assemblage and substrate quality effects on microbial priming. Geoderma, 322, 38--47.
• Heckman, K., Throckmorton, H., Horwath, W., Swanston, C., & Rasmussen, C. (2018). Variation in the Molecular Structure and Radiocarbon Abundance of Mineral-Associated Organic Matter across a Lithosequence of Forest Soils. Soil Systems, 2(2), 36.
• Kobayashi, T., Rasmussen, C., & Sumida, H. (2018). Characterization of the perylenequinone pigments in Japanese Andosols and Cambisol. Soil Science and Plant Nutrition, 1--10.
• Lybrand, R. A., & Rasmussen, C. (2018). Climate, topography, and dust influences on the mineral and geochemical evolution of granitic soils in southern Arizona. Geoderma, 314, 245--261.
• Pelletier, J. D., Barron-Gafford, G. A., Guti'errez-Jurado, H., Hinckley, E. S., Istanbulluoglu, E., McGuire, L. A., Niu, G., Poulos, M. J., Rasmussen, C., Richardson, P., & others, . (2018). Which way do you lean? Using slope aspect variations to understand Critical Zone processes and feedbacks. Earth Surface Processes and Landforms, 43(5), 1133--1154.
• Perdrial, J., Brooks, P. D., Swetnam, T., Lohse, K. A., Rasmussen, C., Litvak, M., Harpold, A. A., Zapata-Rios, X., Broxton, P., Mitra, B., & others, . (2018). A net ecosystem carbon budget for snow dominated forested headwater catchments: linking water and carbon fluxes to critical zone carbon storage. Biogeochemistry, 138(3), 225--243.
• Rasmussen, C. (2018). Controls on Soil Organic Carbon Partitioning and Stabilization in the California Sierra Nevada. Soil Systems.
• Rasmussen, C. (2018). Signatures of Obliquity and Eccentricity in Soil Chronosequences. Geophysical Research Letters.
• Rasmussen, C. (2018). Why Do Large-Scale Land Surface Models Produce a Low Ratio of Transpiration to Evapotranspiration?. Journal of Geophysical Research: Atmospheres.
• Rasmussen, C., Throckmorton, H., Liles, G., Heckman, K., Meding, S., & Horwath, W. (2018). Controls on Soil Organic Carbon Partitioning and Stabilization in the California Sierra Nevada. Soil Systems, 2(3), 41.
• Regmi, N. R., & Rasmussen, C. (2018). Predictive mapping of soil-landscape relationships in the arid Southwest United States. Catena, 165, 473--486.
• Shepard, C., Pelletier, J. D., Schaap, M. G., & Rasmussen, C. (2018). Signatures of obliquity and eccentricity in soil chronosequences. Geophysical Research Letters, 45(20), 11--147.
• Shepard, C., Schaap, M. G., Chorover, J., & Rasmussen, C. (2018). Understanding Critical Zone Evolution through Predicting the Three-Dimensional Soil Chemical Properties of a Small Forested Catchment. Soil Science Society of America Journal, 82(6), 1538--1550.
• Xie, S., Gallant, E., Wetmore, P. H., Figueiredo, P. M., Owen, L. A., Rasmussen, C., Malservisi, R., & Dixon, T. H. (2018). A new geological slip rate estimate for the Calico Fault, eastern California: implications for geodetic versus geologic rate estimates in the Eastern California Shear Zone. International Geology Review, 1--29.
• Gallery, R. E., Rasmussen, C., Fehmi, J. S., & Gebhardt, M. (2017). Soil amendments alter plant biomass and soil microbial activity in a semi-desert grassland. Plant and Soil, 419, 53-70. doi:DOI:10.1007/s11104-017-3327-5
• Gebhardt, M., Fehmi, J. S., Rasmussen, C., & Gallery, R. E. (2017). Soil amendments alter plant biomass and soil microbial activity in a semi-desert grassland. Plant and Soil, 419(1-2), 53--70.
• Lybrand, R. A., Heckman, K., & Rasmussen, C. (2017). Soil organic carbon partitioning and $Delta$14C variation in desert and conifer ecosystems of southern Arizona. Biogeochemistry, 134(3), 261--277.
• McIntosh, J. C., Schaumberg, C., Perdrial, J., Harpold, A., V'azquez-Ortega, A., Rasmussen, C., Vinson, D., Zapata-Rios, X., Brooks, P. D., Meixner, T., & others, . (2017). Geochemical evolution of the Critical Zone across variable time scales informs concentration-discharge relationships: Jemez River Basin Critical Zone Observatory. Water Resources Research, 53(5), 4169--4196.
• Pelletier, J. D., Barron-Gafford, G. A., Guttierez-Jurado, H., Hinckley, E. S., Istanbulluoglu, E., McGuire, L. A., Niu, G., Poulos, M. J., Rasmussen, C., Richardson, P., & others, . (2017). Which way do you lean? Using slope aspect variations to understand Critical Zone processes and feedbacks. Earth Surface Processes and Landforms.
• Rasmussen, C., McGuire, L., Dhakal, P., & Pelletier, J. D. (2017). Coevolution of soil and topography across a semiarid cinder cone chronosequence. CATENA, 156, 338--352.
• Shepard, C., Schaap, M. G., Pelletier, J. D., & Rasmussen, C. (2017). A probabilistic approach to quantifying soil physical properties via time-integrated energy and mass input. Soil, 3(1), 67.
• Huckle, D., Ma, L., Mcintosh, J. C., Vazquez-Ortega, A., Rasmussen, C., & Chorover, J. D. (2016). U-series isotopic signatures of soils and headwater streams in a semi-arid complex volcanic terrain. Chemical Geology, 445, 68-83.
• Huckle, D., Ma, L., Mcintosh, J. C., Vazquez-Ortega, A., Rasmussen, C., & Chorover, J. D. (2016). U-series osotopic signatures of soils and headwater streams in a semi-arid complex volcanic terrain. Chem Geol., 445, 68-83.
• Rasmussen, C., Troch, P. A., Pelletier, J. D., Swetnam, T. W., & Chorover, J. D. (2015). Quantifying topographic and vegetation effects on the trnasfer of energy and mass to a critical zone. Vadose Zone Journal.
• Vazquez-Ortega, A., Huckle, D., Perdrial, J., Amistadi, M. K., Durcik, M., Rasmussen, C., Mcintosh, J. C., & Chorover, J. D. (2016). Solid-phase redistribution of rare earth elements in hillslope pedons subjected to different hydrologic fluxes. Chemical Geology, 426, 1-18.
• Vázquez-Ortega, A., Vázquez-Ortega, A., Huckle, D., Huckle, D., Perdrial, J., Perdrial, J., Amistadi, M. K., Amistadi, M. K., Durcik, M., Durcik, M., Rasmussen, C., Rasmussen, C., Mcintosh, J. C., Mcintosh, J. C., Chorover, J. D., & Chorover, J. D. (2016). Solid-phase redistribution of rare earth elements in hillslope pedons subjected to different hydrologic fluxes. Chemical Geology, 426, 1-18. doi:10.1016/j.chemgeo.2016.01.001
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  Prior studies indicate that patterns of rare earth element (REE) depletion or enrichment in critical zone (CZ) weathering systems are sensitive to variation not only in lithology, but also in climatic and/or biological processes. Organic ligands and secondary mineral surfaces vary in complex stability with different lanthanide series metals, which can result in solid-solution fractionation during incongruent mineral dissolution. REE fractionation during precipitation of solid phase weathering products is also expected to vary with host phase affinity and aqueous geochemistry along fluid flow paths. We postulated that patterns of REE fractionation during pedogenic weathering would exhibit mass-dependent trends as a function of depth in the soil profile. We further hypothesized that REE signatures would be influenced by depth-dependent variation in water and dissolved organic carbon (DOC) fluxes resulting from topographic position of the pedon under investigation. Field-based hypothesis testing utilized instrumented pedons derived from rhyolitic bedrock overlain by mixed conifer forest in the Jemez River Basin Critical Zone Observatory (JRB-CZO). REE depletion trends correlated with topographically-induced variation in soil pore water and DOC through-fluxes occurring predominantly during winter snowmelt. Bulk regolith analyses indicated that light rare earth elements (LREE) were depleted preferentially relative to medium and heavy REE (MREE and HREE). Lateral fluxes of water and DOC through subsurface horizons in the concave hillslope pedon correlated not only with greater REE depletion, but also with greater fractionation of REE into organo-metal colloid forms (2-23%) relative to a planar site hillslope pedon (3-13%) where vertical water and DOC fluxes were predominant. MREEs were preferentially retained in secondary colloids, indicating a mechanism for their stabilization in the weathering profile. Positive Ce-anomalies in the soils were the result of Ce retention in pedogenic Fe-(oxy)hydroxides.
• Zapata-Rios, X., Brooks, P. D., Troch, P. A., McIntosh, J., & Rasmussen, C. (2016). Influence of climate variability on water partitioning and effective energy and mass transfer in a semi-arid critical zone. Hydrology and Earth System Sciences, 20(3), 1103--1115.
• Chorover, J. D., Zapata-Rios, X. E., Mcintosh, J., Rademacher, L., Troch, P. A., Brooks, P. D., & Rasmussen, C. (2015). Climatic and landscape controls on water transit times and silicate mineral weathering in the critical zone.. Water Resour. Res., 51, 6036-6051. doi:10.1002/2015WR017018
• Crouvi, O., Polyakov, V. O., Pelletier, J. D., & Rasmussen, C. (2015). Decadal-scale soil redistribution along hillslopes in the Mojave Desert. EARTH SURFACE DYNAMICS, 3(2), 251-264.
• Field, J. P., Field, J. P., Breshears, D. D., Breshears, D. D., Law, D. J., Law, D. J., Villegas, j. C., Lopez Hoffman, L. -., Brooks, P. D., Lopez Hoffman, L. -., Chorover, J., Brooks, P. D., Barron-Gafford, G. A., Chorover, J., Gallery, R. E., Barron-Gafford, G. A., Litvak, M. E., Gallery, R. E., Litvak, M. E., , Lybrand, R., et al. (2015). Critical zone services: Expanding context, constraints, and curency beyond ecosystem services.. Vadose Zone Journal, 1-7.
• Holleran, M., Levi, M., & Rasmussen, C. (2015). Quantifying soil and critical zone variability in a forested catchment through digital soil mapping. Soil, 1.
• Levi, M. R., Schaap, M. G., & Rasmussen, C. (2015). Application of Spatial Pedotransfer Functions to Understand Soil Modulation of Vegetation Response to Climate. VADOSE ZONE JOURNAL, 14(9).
• Lybrand, R. A., & Rasmussen, C. (2015). Quantifying climate and landscape position controls on soil development in semiarid ecosystems. Soil Science Society of America Journal, 79(1), 104--116.
• Pangle, L. A., Chorover, J. D., Delong, S. B., Pangle, L. A., Abramson, N., Delong, S. B., Adams, J., Abramson, N., Barron-Gafford, G. A., Adams, J., Breshears, D. D., Barron-Gafford, G. A., Brooks, P. D., Breshears, D. D., Chorover, J. D., Brooks, P. D., Dietrich, W. E., Dietrich, W. E., Dontsova, K. M., , Dontsova, K. M., et al. (2015). The Landscape Evolution Observatory: A large-scale controllable infrastructure to study Earth-surface processes.. Geomorphology, 244, 190-203.
• Pangle, L., DeLong, S., Abramson, N., Adams, J., Barron-Gafford, G. A., Breshears, D. D., Brooks, P. D., Chorover, J. D., Dietrich, W. E., Dontsova, K. M., Durcik, M., Espeleta, J., Ferre, P. A., Ferriere, R. H., Henderson, W., Hunt, E., Huxman, T. E., Millar, D., Murphy, B., , Niu, Y., et al. (2015). The Landscape Evolution Observatory: A large-scale controllable infrastructure to study coupled Earth-surface processes. Geomorphology, 244, 190-203.
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• Rasmussen, C., Gallery, R. E., & Fehmi, J. S. (2015). Passive soil heating using an inexpensive infrared mirror design – a proof of concept. Soil, 1, 631-639. doi:10.5194/soil-1-631-2015
• Rasmussen, C., Gallery, R. E., & Fehmi, J. S. (2015). Passive soil heating using an inexpensive infrared mirror design – a proof of concept.. SOIL, 631-639. doi:doi:10.5194/soil-1-631-2015
• Rasmussen, C., Rasmussen, C., Troch, P. A., Pelletier, J. D., Pelletier, J. D., Troch, P. A., Swetnam, T. W., Swetnam, T. W., Chorover, J. D., & Chorover, J. D. (2015). Quantifying topographic and vegetation effects on the trnasfer of energy and mass to a critical zone. Vadose Zone Journal.
• Shepard, C., Schaap, M. G., Crimmins, M. A., Leeuwen, W. J., & Rasmussen, C. (2015). Subsurface soil textural control of aboveground productivity in the US Desert Southwest. Geoderma Regional, 4, 44--54.
• V\'azquez-Ortega, A., Perdrial, J., Harpold, A., Zapata-R\'\ios, X., Rasmussen, C., McIntosh, J., Schaap, M., Pelletier, J. D., Brooks, P. D., Amistadi, M. K., & others, . (2015). Rare earth elements as reactive tracers of biogeochemical weathering in forested rhyolitic terrain. Chemical Geology, 391, 19--32.
• Vazquez-Ortega, A., Perdrial, J., Harpold, A., Zapata-Rios, X., Rasmussen, C., McIntosh, J., Schaap, M. G., Pelletier, J. D., Brooks, P. D., Amistadi, M. K., & Chorover, J. D. (2015). Rare earth elements as reactive tracers of biogeochemical weathering in forested rhyolitic terrain. Chem. Geol., 391, 19-32.
• Zapata-Rios, X., Mcintosh, J. C., Rademacher, L., Troch, P. A., Brooks, P. D., Rasmussen, C., & Chorover, J. D. (2015). Climatic and landscape controls on water transit times and silicate mineral weathering in the Critical Zone. Water Resources Research.
• Chorover, J. D., Vazquez-Ortega, A., Perdrial, J., Harpold, A., Zapata-Rios, X., McIntosh, J., Rasmussen, C., Schaap, M. G., Pelletier, J. D., Brooks, P. D., & Amistadi, M. K. (2014). Rare earth elements as reactive tracers of biogeochemical weathering in forested rhyolitic terrain. Chem. Geol., 391, 19-32.
• Crouvi, O., Polyakov, V., Pelletier, J., & Rasmussen, C. (2014). Controls on slope-wash erosion rates in the Mojave Desert. Earth Surface Dynamics Discussions, 2(1), 535--574.
• Heckman, K., Throckmorton, H., Clingensmith, C., Vila, F. J., Horwath, W. R., Knicker, H., & Rasmussen, C. (2014). Factors affecting the molecular structure and mean residence time of occluded organics in a lithosequence of soils under ponderosa pine. Soil Biology and Biochemistry, 77, 1--11.
• Levi, M. R., & Rasmussen, C. (2014). Covariate selection with iterative principal component analysis for predicting physical soil properties. Geoderma, 219, 46--57.
• Lybrand, R. A., & Rasmussen, C. (2014). A Cross-scale Study of Feldspar Transformation in the Santa Catalina Mountain Critical Zone Observatory. Procedia Earth and Planetary Science, 10, 63--68.
• Lybrand, R. A., & Rasmussen, C. (2014). Linking soil element-mass-transfer to microscale mineral weathering across a semiarid environmental gradient. Chemical Geology, 381, 26--39.
• Nauman, T. W., Thompson, J. A., & Rasmussen, C. (2014). Semi-Automated Disaggregation of a Conventional Soil Map Using Knowledge Driven Data Mining and Random Forests in the Sonoran Desert, USA. Photogrammetric Engineering \& Remote Sensing, 80(4), 353--366.
• Pangle, L., DeLong, S., Abramson, N., Adams, J., Barron-Gafford, G. A., Breshears, D. D., Brooks, P. D., Chorover, J. D., Dietrich, W. E., Dontsova, K. M., Durcik, M., Espeleta, J., Ferre, P. A., Ferriere, R. H., Henderson, W., Hunt, E., Huxman, T. E., Millar, D., Murphy, B., , Niu, Y., et al. (2015). The Landscape Evolution Observatory: A large-scale controllable infrastructure to study coupled Earth-surface processes. Geomorphology.
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• V\'azquez-Ortega, A., Hernandez-Ruiz, S., Amistadi, M. K., Rasmussen, C., & Chorover, J. (2014). Fractionation of dissolved organic matter by (oxy) hydroxide-coated sands: Competitive sorbate displacement during reactive transport. Vadose Zone Journal, 13(7).
• Crouvi, O., Pelletier, J. D., & Rasmussen, C. (2013). Predicting the thickness and aeolian fraction of soils in upland watersheds of the Mojave Desert. Geoderma, 195, 94--110.
• Heckman, K., Grandy, A. S., Gao, X. D., Keiluweit, M., Wickings, K., Carpenter, K., Chorover, J., & Rasmussen, C. (2013). Sorptive fractionation of organic matter and formation of organo-hydroxy-aluminum complexes during litter biodegradation in the presence of gibbsite.. Geochim. Cosmochim. Acta, 121, 667-683.
• Heckman, K., Grandy, A., Gao, X., Keiluweit, M., Wickings, K., Carpenter, K., Chorover, J., & Rasmussen, C. (2013). Sorptive fractionation of organic matter and formation of organo-hydroxy-aluminum complexes during litter biodegradation in the presence of gibbsite. Geochimica et Cosmochimica Acta, 121, 667--683.
• Heckman, K., Welty-Bernard, A., Vazquez-Ortega, A., Schwartz, E., Chorover, J., & Rasmussen, C. (2013). The influence of goethite and gibbsite on soluble nutrient dynamics and microbial community composition. Biogeochem., 112, 179-195.
• Heckman, K., Welty-Bernard, A., Vazquez-Ortega, A., Schwartz, E., Chorover, J., & Rasmussen, C. (2013). The influence of goethite and gibbsite on soluble nutrient dynamics and microbial community composition. Biogeochemistry, 112(1-3), 179--195.
• Pelletier, J. D., Barron-Gafford, G. A., Breshears, D. D., Brooks, P. D., Chorover, J., Durcik, M., Harman, C. J., Huxman, T. E., Lohse, K. A., Lybrand, R., & others, . (2013). Coevolution of nonlinear trends in vegetation, soils, and topography with elevation and slope aspect: A case study in the sky islands of southern Arizona. Journal of Geophysical Research: Earth Surface, 118(2), 741--758.
• Pelletier, J. D., Barron-Gafford, G. A., Breshears, D. D., Brooks, P. D., Chorover, J., Durcik, M., Harman, C. J., Huxman, T. E., Lohse, K. A., Lybrand, R., Meixner, T., Mcintosh, J. C., Papuga, S. A., Rasmussen, C., Schaap, M. G., Swetnam, T. W., & Troch, P. A. (2013). Coevolution of nonlinear trends in vegetation, soils, and topography with elevation and slope aspect: A case study in the sky islands of southern Arizona. J. Geophys. Res. - Earth Surf., 118, 741-758.
• Pelletier, J. D., Pelletier, J. D., Breshears, D. D., Breshears, D. D., Barron-Gafford, G. A., Barron-Gafford, G. A., Brooks, P. D., Brooks, P. D., Chorover, J., Chorover, J. D., Durick, M., Durick, M., Harman, C. J., Harman, C. J., Huxman, T. E., Huxman, T. E., Lohse, K. A., Lohse, K. A., Lybrand, R., , Lybrand, R., et al. (2013). Coevolution of nonlinear trends in vegetation, soils, and topography with elevation and slope aspect: A case study in the sky islands of southern Arizona. Journal of Geophysical Research - Earth Surface, 118(2), 1-18.
• RASMUSSEN, C. (2013). THE INTERACTION OF DUST, TOPOGRAPHY, AND PEDOGENESIS IN VOLCANIC TERRAIN OF THE SOUTHWESTERN US. Geological Society of America Abstracts with Programs, 45(7), 0.
• Rasmussen, C., & Gallo, E. (2013). Technical Note: A comparison of model and empirical measures of catchment scale effective energy and mass transfer.. Hydrology \& Earth System Sciences Discussions, 10(3).
• Artiola, J. F., Rasmussen, C., & Freitas, R. (2012). Effects of a biochar-amended alkaline soil on the growth of romaine lettuce and bermudagrass. Soil Science, 177(9), 561-570.
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  Abstract: Biochar from pine forest waste (PFW) was used in greenhouse pot experiments to evaluate plant growth using two levels (2% and 4% wt/wt) of biochar amendments applied to an alkaline, loamy sand soil. Biochar soil additions induced a large decrease in the soil bulk density (from 1.59 to 1.26 g cm) and large to moderate increases in gravimetric and volumetric soil-water contents, respectively, under pot and field moisture capacity conditions. The growth of romaine lettuce was initially adversely affected in the 4% biochar-amended soil. However, bermudagrass benefited from the biochar addition with increased biomass production and enhanced drought resistance. Both plant species showed statistically significant increases (compared with controls) in biomass yields at the 2% but not at the 4% biochar application rate. An incubation study indicated that soil microbial activity, as measured by evolved CO2, was significantly suppressed (-31% compared with the control) in the presence of biochar over a period of 4 months. The data indicated that addition of PFW biochar induced a species-dependent plant response and produced an overall decrease in microbial mineralization of organic materials. Vegetables such as lettuce may benefit from a period of excess irrigation, to leach any potentially toxic biochar-introduced salts or organic compounds, before seeding. Conversely, warm season grasses may adapt quickly to a soil amended with PFW biochar with increased biomass production and drought resistance. Copyright © 2012 by Lippincott Williams & Wilkins.
• Artiola, J., Rasmussen, C., & Freitas, R. (2012). Greenhouse studies using a desert, alkaline soil amended with pine forest waste biochar to grow Romaine lettuce and Bermuda grass. Soil Science, 177, 561-570.
• Heckman, K., Bernard, A., Vazquez-Ortega, A., Schwartz, E., Chorover, J., & Rasmussen, C. (2012). The influence of goethite and gibbsite on soluble nutrient dynamics and microbial community composition. Biogeochemistry, 1-17.
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  DOI 10.1007/s10533-012-9715-2
• Legatzki, A., Ortiz, M., Neilson, J., Casavant, R., Palmer, M., Rasmussen, C., Pryor, B., Pierson, I. L., & Maier, R. (2012). Factors influencing observed variations in the structure of bacterial communities on calcite formations in Kartchner Caverns, AZ, USA. Geomicrobiology Journal, 29, 422-434.
• Rasmussen, C. (2012). Thermodynamic constraints on effective energy and mass transfer and catchment function. Hydrology and Earth System Sciences, 16(3), 725-739.
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  Abstract: Understanding how water, energy and carbon are partitioned to primary production and effective precipitation is central to quantifying the limits on critical zone evolution. Recent work suggests quantifying energetic transfers to the critical zone in the form of effective precipitation and primary production provides a first order approximation of critical zone process and structural organization. However, explicit linkage of this effective energy and mass transfer (EEMT; W m -2) to critical zone state variables and well defined physical limits remains to be developed. The objective of this work was to place EEMT in the context of thermodynamic state variables of temperature and vapor pressure deficit, with explicit definition of EEMT physical limits using a global climate dataset. The relation of EEMT to empirical measures of catchment function was also examined using a subset of the Model Parameter Estimation Experiment (MOPEX) catchments. The data demonstrated three physical limits for EEMT: (i) an absolute vapor pressure deficit threshold of 1200 Pa above which EEMT is zero; (ii) a temperature dependent vapor pressure deficit limit following the saturated vapor pressure function up to a temperature of 292 K; and (iii) a minimum precipitation threshold required from EEMT production at temperatures greater than 292 K. Within these limits, EEMT scales directly with precipitation, with increasing conversion of the precipitation to EEMT with increasing temperature. The state-space framework derived here presents a simplified framework with well-defined physical limits that has the potential for directly integrating regional to pedon scale heterogeneity in effective energy and mass transfer relative to critical zone structure and function within a common thermodynamic framework. © Author(s) 2012.
• Rasmussen, C. (2012). Thermodynamic constraints on effective energy and mass transfer and catchment function. Hydrology and Earth System Sciences, 16, 725-739.
• , J., Plante, A., Leifeld, J., & Rasmussen, C. (2011). Methodological considerations for using thermal analysis in the characterization of soil organic matter. Journal of Thermal Analysis and Calorimetry, 104, 389-398.
• Chorover, J., Troch, P. A., Rasmussen, C., Brooks, P. D., Pelletier, J. D., Breshears, D. D., Huxman, T. E., Kurc, S. A., Lohse, K., Mcintosh, J. C., Meixner, T., Schaap, M. G., Litvak, M., Perdrial, J., Harpold, A., & Durcik, M. (2011). How water, carbon, and energy drive critical zone evolution: the Jemez-Santa Catalina Critical Zone Observatory. Vadose Zone Journal, 10, 884-899.
• Chorover, J., Troch, P., Rasmussen, C., Brooks, P., Pelletier, J., Breshears, D., Huxman, T., Lohse, K., McIntosh, J., Meixner, T., Papuga, S., Schaap, M., Litvak, M., Perdrial, J., Harpold, A., & Durcik, M. (2011). How Water, Carbon, and Energy Drive Critical Zone Evolution: The Jemez-Santa Catalina Critical Zone Observatory. Vadose Zone Journal, 10(3), 884-899.
• De, D., Bacon, A. R., Megan, L. M., Richardson, C. J., Andrews, S. S., West, L., Wills, S., Billings, S., Cambardella, C. A., Cavallaro, N., DeMeester, J. E., Franzluebbers, A. J., Grandy, A. S., Grunwald, S., Gruver, J., Hartshorn, A. S., Janzen, H., Kramer, M. G., Ladha, J. K., , Lajtha, K., et al. (2011). Human-soil relations are changing rapidly: Proposals from SSSA's cross-divisional soil change working group. Soil Science Society of America Journal, 75(6), 2079-2084.
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  Abstract: A number of scientists have named our age the Anthropocene because humanity is globally affecting Earth systems, including the soil. Global soil change raises important questions about the future of soil, the environment, and human society. Although many soil scientists strive to understand human forcings as integral to soil genesis, there remains an explicit need for a science of anthropedology to detail how humanity is a fully fledged soil-forming factor and to understand how soil change affects human well being. The development and maturation of anthropedology is critical to achieving land-use sustainability and needs to be nurtured by all soil disciplines, with inputs from allied sciences and the humanities,. The Soil Science Society of America (SSSA) has recently approved a cross-divisional Working Group on Soil Change, which aims to advance the basic and applied science of anthropedology, to facilitate networks of scientists, long-term soil field studies, and regional databases and modeling, and to engage in new modes of communications about human-soil relations. We challenge all interested parties, especially young scientists and students, to contribute to these activities and help grow soil science in the Anthropocene. © Soil Science Society of America, 5585 Guilford Rd., Madison WI 53711 USA. All rights reserved.
• Fernández, J. M., Plante, A. F., Leifeld, J., & Rasmussen, C. (2011). Methodological considerations for using thermal analysis in the characterization of soil organic matter. Journal of Thermal Analysis and Calorimetry, 104(1), 389-398.
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  Abstract: Thermal analysis is primarily used in the field of materials science, but has a long history in the geosciences. Soil organic matter (SOM) has received a great deal of recent scientific interest because of its role in the global carbon cycle. Conventional methods of characterizing SOM quality are unsatisfactory because they do not adequately capture the complete quality continuum that SOM comprises or the various mechanisms that act to stabilize it in the soil matrix. Thermal analysis techniques have the potential to capture this quality continuum, but are dependent on numerous experimental conditions that limit the comparability of results among different studies. Published methodology on thermal analysis of soils and sediments has largely focused on the characterization of the mineral component, while the organic component has received little attention. We tested several experimental conditions for their effects on the exothermic region of curves generated by thermal analysis of easily dispersed soil clay fractions and non-protected light-density particulate organic matter fractions isolated from the surface horizon of a forest soil. Results were found to be highly repeatable but strongly sensitive to crucible material, heating rate, and sample amount, and relatively insensitive to the use of a reference material. Thermal analysis is an important addition to the set of analytical tools used to characterize SOM quality because it provides direct, quantitative information of the energy potentially available for microbial metabolism. However, users will need to balance the needs of specific scientific objectives with the need for standardized methods and comparability between studies. © Akadémiai Kiadó, Budapest, Hungary 2010.
• Heckman, K., & Rasmussen, C. (2011). Lithologic controls on regolith weathering and mass flux in forested ecosystems of the southwestern USA. Geoderma, 164(3-4), 99-111.
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  Abstract: Parent material has a profound impact on chemical weathering, mineral transformation and chemical denudation. However, there remains a relative paucity of lithosequence studies that directly examine parent material control on pedogenic processes. We sampled a lithosequence of four parent materials (rhyolite, granite, basalt, dolostone/volcanic cinders) under Pinus ponderosa in mesic and ustic soil moisture and temperature regimes of central and southern Arizona, USA to quantify the contribution of parent material to chemical weathering and elemental mass flux. We quantified chemical weathering and mass flux using a combination of quantitative X-ray diffraction and elemental mass balance. Mass flux calculations were confounded by the addition of volcanic cinders in the dolostone soils and addition of eolian materials in both the basalt and dolostone soils. These variations in parent material were accounted for using a combination of refractory element indices and X-ray diffraction. Results indicated significant differences in profile characteristics and chemical weathering among parent materials. Chemical mass loss from the basalt and dolostone soils were balanced or exceeded by addition of eolian materials, leading to positive and highly variable mass fluxes of 14±48kgm-2 and -10±22kgm-2, respectively. Rhyolite and granite soils exhibited large differences in chemical mass flux despite nearly identical elemental and mineralogical compositions of the respective parent materials. Total chemical mass flux from the granite soils averaged -173±31kgm-2, whereas mass flux from the rhyolite soils was much larger, on the order of -930±71kgm-2. These large differences result from the variation of parent material grain size and bulk density. The data demonstrate strong control of parent material on chemical weathering and mass flux in cool, semiarid forested ecosystems. © 2011.
• Heckman, K., & Rasmussen, C. (2011). Lithologic controls on regolith weathering and mass flux in forested ecosystems of the southwestern USA. Geoderma, 164, 99-111.
• Heckman, K., Vazquez-Ortega, A., Gao, X., Chorover, J., & Rasmussen, C. (2011). Changes in water extractable organic matter during incubation of forest floor material in the presence of quartz, goethite and gibbsite surfaces. Geochimica et Cosmochimica Acta, 75, 4295-4309.
• Levi, M., & Rasmussen, C. (2011). Considerations for Atmospheric Correction of Surface Reflectance for Soil Survey Applications. Soil Survey Horizons, 52, 48-55.
• Lybrand, R., Rasmussen, C., Jardine, A., Troch, P., & Chorover, J. (2011). The effects of climate and landscape position on chemical denudation and mineral transformation in the Santa Catalina mountain critical zone observatory. Applied Geochemistry, 26(S), S80-S84.
• Pelletier, J., McGuire, L., Ash, J., Engelder, T., Hill, L., Leroy, K., Orem, C., Rosenthal, S., Trees, M., Rasmussen, C., & Chorover, J. (2011). Calibration and testing of upland hillslope evolution models in a dated landscape: Banco Bonito, New Mexico, USA. Journal of Geophysical Research.
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  doi:10.1029/2011JF001976
• Rasmussen, C., Brantley, S., Richter, D., Blum, A., Dixon, J., & White, A. (2011). Strong climate and tectonic control on plagioclase weathering in granitic terrain. Earth and Planetary Science Letters, 301, 521-530.
• Rasmussen, C., Brantley, S., de, D., Blum, A., Dixon, J., & White, A. F. (2011). Strong climate and tectonic control on plagioclase weathering in granitic terrain. Earth and Planetary Science Letters, 301(3-4), 521-530.
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  Abstract: Investigations to understand linkages among climate, erosion and weathering are central to quantifying landscape evolution. We approach these linkages through synthesis of regolith data for granitic terrain compiled with respect to climate, geochemistry, and denudation rates for low sloping upland profiles. Focusing on Na as a proxy for plagioclase weathering, we quantified regolith Na depletion, Na mass loss, and the relative partitioning of denudation to physical and chemical contributions. The depth and magnitude of regolith Na depletion increased continuously with increasing water availability, except for locations with mean annual temperature
• Rasmussen, C., Troch, P., Chorover, J., Brooks, P., Pelletier, J., & Huxman, T. (2011). An open system framework for integrating critical zone structure and function. Biogeochemistry, 102, 15-29.
• Díaz, F. J., O'Geen, A. T., Rasmussen, C., & Dahlgren, R. A. (2010). Pedogenesis along a thermal gradient in a geothermal region of the southern Cascades, California. Geoderma, 154(3-4), 495-507.
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  Abstract: Hydrothermal alteration is an important soil forming factor in the vicinity of active volcanic centers, yet we are aware of no studies that have addressed the role of active fumaroles on soil development. This paper examines a soil developmental sequence of five pedons established across a thermal gradient (∼ 100 m) induced by an active fumarole in Lassen Volcanic National Park in the southern Cascades of California. The soil temperature gradient at the time of sampling ranged from 100 to 15 °C with a corresponding change in vegetation from barren areas near the fumarole, to pygmy conifer, conifer, and meadow (grasses and herbs) with increasing distance from the fumarole. The primary objectives of this study were to characterize morphological, chemical, and mineralogical soil properties across the thermal gradient, and document pedogenic processes within this exotic soil forming environment. Field morphological properties, standard soil characterization, soil solution chemistry and detailed mineralogical investigations were conducted. The hydrothermally altered parent material from which the soils formed was relatively clay-rich (18-48% clay) with a mineralogical composition dominated by mica-smectite, chlorite, and montmorillonite. Soils near the fumarole were strongly acidified (pH < 4) by sulfuric acid and pH values increased with distance from the fumarole (conifer pH = 4.5-5.5; meadow pH > 6). High soil temperatures near the fumarole resulted in iron (hydr)oxides being primarily crystalline, while non-crystalline iron (hydr)oxides were generally dominant in the upper horizons of the non-thermal soils. Steam-heated alteration in the vicinity of the fumarole resulted in the transformation of the mica-smectite and chlorite to smectite, kaolinite, and alunite (KAl(SO4)2). A similar, but less intense alteration appeared in the conifer pedons resulting in both smectite and kaolinite as weathering products. The meadow pedon displayed the least alteration with appreciable mica-smectite and/or chlorite-smectite still present. There was no evidence of poorly crystalline aluminosilicates materials (e.g., allophane, imogolite) in any of the soils. The lack of vegetation establishment on soils near the fumarole appears to result primarily from the high soil temperatures (> 59 °C at 50 cm), with strong soil acidity (pH < 4), high exchangeable Al3+ (generally > 10 cmolc kg- 1), low base saturation, and low nutrients further impairing soil fertility. © 2009 Elsevier B.V. All rights reserved.
• Rasmussen, C., & White, D. A. (2010). Vegetation effects on soil organic carbon quality in an arid hyperthermic ecosystem. Soil Science, 175(9), 438-446.
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  Abstract: Arid lands occupy substantial global land area and thus may play an important role in the terrestrial carbon cycle. This study examined a facet of arid land carbon cycling by examining variation in plant and soil organic carbon quality and the physical partitioning of carbon into aggregate and mineral-associated fractions for soils dominated by Prosopis velutina (mesquite), Larrea tridentata (creosote), and a combination of Bouteloua barbata, Bouteloua aristidoides, Aristida adscensionis, and Cynodon dactylon (mixed grass) vegetation types in an arid hyperthermic ecosystem. We used a combination of density fractionation to quantify physical distribution of organic carbon, in addition to isotopic, thermal, and spectroscopic techniques to quantify carbon quality in each fraction. Data indicated that most of the soil carbon across all vegetation types was concentrated in free light fractions, with little role for aggregate occlusion or mineral adsorption. Differential thermal analysis and derivative thermogravimetry indicated that all vegetation types were dominated by thermally labile material (exothermic peak and mass loss at ∼350°C), with the greatest differences in carbon quality noted among the respective plant materials. Diffuse reflectance Fourier transform infrared spectroscopy also indicated that the most substantial variation in organic carbon chemical quality was among the various plant materials. In particular, the creosote plant material exhibited a distinct high-temperature exothermic peak near 515°C, the greatest specific enthalpy (20 kJ g-1 biomass), and a relatively greater proportion of aromatic components as determined by diffuse reflectance Fourier transform infrared spectroscopy. Furthermore, the data indicated substantial alteration of chemical and thermal properties as organic material progressed from plant material to the soil fractions with a convergence on organic material dominated by polysaccharides and substantial reduction in specific enthalpy in the soil fractions. Copyright © 2010 by Lippincott Williams & Wilkins.
• Rasmussen, C., Dahlgren, R. A., & Southard, R. J. (2010). Basalt weathering and pedogenesis across an environmental gradient in the southern Cascade Range, California, USA. Geoderma, 154(3-4), 473-485.
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  Abstract: Basalt rocks occupy substantial land area and play a significant role in global weathering patterns and biogeochemical cycling. The objective of this research was to quantify climatic controls of weathering and pedogenic processes on basalt-derived soils across an environmental gradient on the western slope of the Casacade Range of California, USA. We hypothesized that climate controls mineral neogenesis, with cool, moist conditions favoring formation of short-range-order (SRO) materials and warm, dry conditions favoring smectite, crystalline Fe-oxyhydroxides and kaolins. Four pedons were sampled across an elevation gradient (250-2500 m) having large variation in mean annual soil temperature (5-17 °C) and mean annual precipitation (750-1350 mm). The soil mineral assemblage was characterized by X-ray diffraction, selective dissolution, total elemental analysis and light microscopy. The degree of weathering and mineral assemblage exhibited a clear threshold at the permanent winter snowline (~ 1200 m). Maximum soil development was noted just below the snowline with soils dominated by kaolinite and dehydrated halloysite, crystalline Fe-oxyhydroxides (48 kg m- 2), extensive loss of cations (chemical index of alteration, CIA > 95%) and clay accumulation (447 kg m- 2). In contrast, the high elevation snow-dominated pedons displayed less intense weathering (e.g., CIA < 75% and clay < 25 kg m- 2) and a mineral assemblage dominated by primary minerals and SRO materials. The cool, moist conditions of mid-altitude (~ 1600 m) soils appear optimum for the formation and preservation of SRO materials (allophane = 30 kg m- 2). All pedons contained hydroxy-Al interlayered smectite that was either neogenic or derived from eolian minerals. With increasing elevation soil development followed Alfisols → Ultisols → Andisols → Entisols, in agreement with similar gradients in the California Sierra Nevada. Weathering, mineralogical transformations and soil development are limited by water availability at low elevations, whereas low soil temperature is the major limitation at high elevations. © 2009 Elsevier B.V. All rights reserved.
• A., D., Welty-Bernard, A., Rasmussen, C., & Schwartz, E. (2009). Vegetation controls on soil organic carbon dynamics in an arid, hyperthermic ecosystem. Geoderma, 150(1-2), 214-223.
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  Abstract: The large land area occupied by arid lands, roughly 36% to 40% globally, underscores the importance for understanding how these ecosystems function in the global carbon cycle. Few studies have directly examined soil organic carbon (SOC) dynamics and the effect of vegetation on SOC and microbial community structure in arid ecosystems. The objective of this study was to determine the effect of vegetation type on SOC dynamics in an arid, hyperthermic Sonoran Desert ecosystem. We specifically examined the influence of Prosopis velutina (mesquite), Larrea tridentata (creosote), and a combination of Bouteloua barbata, Bouteloua aristidoides, Aristida adscensionis, and Cynodon dactylon (mixed grass) vegetation types on SOC dynamics by quantifying: (i) local scale SOC stocks; (ii) soil aggregate stability; (iii) SOC turnover; and (iv) soil microbial community composition. There was significantly greater SOC in mesquite A-horizons relative to creosote and grass sites with values of 46.7, 30.4, and 24.4 g m- 2, respectively. Subsurface SOC content did not vary significantly between vegetation types. Aggregate stability determined using an ultrasonic dispersion technique was found to be similar among vegetation types. The only significant difference noted was greater energy required to disperse stable aggregates in mesquite relative to grass soils, 1500 and 735 J g- 1 soil, respectively. Laboratory incubations were performed to determine SOC dynamics, pool sizes, and active pool mean residence times (MRT) for each vegetation type. Incubation results indicated significant variation in the cumulative respired CO2 under mesquite, creosote, and grasses with 151, 186, and 207 mg C g- 1 soil C respired from each respective vegetation type. The incubation data indicated that 7-11% of total SOC was highly labile across all vegetation types with modeled active pool SOC MRT averaging 17 days. Bacterial community analysis by Terminal Restriction Fragment Length Polymorphism (TRFLP) indicated significant differences in microbial community structure among vegetation types. Microbial composition was highly correlated with soil pH and electrical conductivity. Furthermore, community composition was correlated with cumulative respired CO2, suggesting an interaction among vegetation type, soil properties and microbial community control SOC dynamics in this ecosystem. The combined results indicated significant variation in SOC dynamics within a specific ecosystem by vegetation type. Understanding local-scale vegetation controls of soil carbon cycling may improve efforts to model regional carbon dynamics in arid environments. © 2009 Elsevier B.V. All rights reserved.
• Heckman, K., Welty-Bernard, A., Rasmussen, C., & Schwartz, E. (2009). Geologic controls of soil carbon cycling and microbial dynamics in temperate conifer forests. Chemical Geology, 267(1-2), 12-23.
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  Abstract: Understanding soil carbon cycling is important for assessing ecosystem response to climate change. Temperate conifer forest soils contain a substantial portion of the global soil C pool and therefore are key components of the global carbon cycle. Despite the importance of temperate forest soil organic carbon (SOC) in the global carbon cycle, the mechanisms and dynamics of SOC accumulation and storage remain poorly understood. To address this knowledge gap, we sampled four soils over different bedrock types (rhyolite, granite, basalt, limestone) under Pinus ponderosa to explore the following questions: i) Within a specific ecosystem type, how do SOC contents vary among sites with differing mineralogy? ii) What physicochemical variables are most highly correlated with SOC content, soil microbial community composition and soil respiration? and iii) What mechanisms account for the influence of these variables on SOC cycling? Soil physiochemical and microbiological properties were characterized and compared on the basis of mineral assemblage, pH, organic carbon content, bacterial community composition, respiration rate, microbial biomass, specific metabolic activity (qCO2), and δ13C of respired CO2. The selected field sites spanned a physicochemical gradient, ranging from acid (pH of 5.2) to basic (pH of 7.1) from rhyolite to granite to basalt to limestone. The acidic rhyolite and granite soils had measurable amounts of exchangeable Al3+ (up to 3 cmol+ kg- 1). SOC content varied significantly among sites, ranging from 3.5 to 11 kg C m- 2.in limestone and rhyolite soils, respectively. Soil bacterial communities were also significantly different among all sites. Metal-humus complex and Fe-oxyhydroxide content emerged as important controllers of SOC dynamics across all sites, showing significant correlation with both SOC content (Al-humus: R2 = 0.71; P < 0.01; Fe-humus: R2 = 0.75; P < 0.001; crystalline FeOx: R2 = 0.63; P < 0.01) and bacterial community composition (Al-humus: R2 = 0.35; P < 0.05; Fe-humus: R2 = 0.51; P < 0.01; oxalate-extractable Fe: R2 = 0.59; P < 0.01). Moreover, soil pH was significantly correlated with exchangeable Al3+, metal-humus complex content, bacterial community composition, and microbial biomass C/N ratios. Results indicated that within a specific ecosystem, SOC dynamics and microbial community vary predictably with soil physicochemical variables directly related to mineralogical differences among soil parent materials. Specifically, the data suggest a gradient in the dominant SOC stabilization mechanism among sites, with chemical recalcitrance and metal-humus complexation the dominant control in soils of the acidic rhyolite and granite sites, and mineral adsorption the dominant factor in the basic limestone and basalt sites. Knowledge of parent material dependent SOC dynamics allows for improved estimates of ecosystem SOC stocks and the potential response of SOC to climate change. © 2009 Elsevier B.V. All rights reserved.
• Rasmussen, C. (2009). Hiding carbon in terrestrial soils. Earth, 54(6), 46-53.
• Rasmussen, C. (2008). Response to comments on "modeling energy inputs to predict pedogenic environments using regional environmental databases". Soil Science Society of America Journal, 72(3), 860-.
• Rasmussen, C., Southard, R. J., & Horwath, W. R. (2008). Litter type and soil minerals control temperate forest soil carbon response to climate change. Global Change Biology, 14(9), 2064-2080.
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  Abstract: Temperate forest soil organic carbon (C) represents a significant pool of terrestrial C that may be released to the atmosphere as CO2 with predicted changes in climate. To address potential feedbacks between climate change and terrestrial C turnover, we quantified forest soil C response to litter type and temperature change as a function of soil parent material. We collected soils from three conifer forests dominated by ponderosa pine (PP; Pinus ponderosa Laws.); white fir [WF; Abies concolor (Gord. and Glend.) Lindl.]; and red fir (RF; Abies magnifica A. Murr.) from each of three parent materials, granite (GR), basalt (BS), and andesite (AN) in the Sierra Nevada of California. Field soils were incubated at their mean annual soil temperature (MAST), with addition of native 13C-labeled litter to characterize soil C mineralization under native climate conditions. Further, we incubated WF soils at PP MAST with 13C-labeled PP litter, and RF soils at WF MAST with 13C-labeled WF litter to simulate a migration of MAST and litter type, and associated change in litter quality, up-elevation in response to predicted climate warming. Results indicated that total CO2 and percent of CO2 derived from soil C varied significantly by parent material, following the pattern of GR > BS > AN. Regression analyses indicated interactive control of C mineralization by litter type and soil minerals. Soils with high short-range-order (SRO) mineral content exhibited little response to varying litter type, whereas PP litter enriched in acid-soluble components promoted a substantial increase of extant soil C mineralization in soils of low SRO mineral content. Climate change conditions increased soil C mineralization greater than 200% in WF forest soils. In contrast, little to no change in soil C mineralization was noted for the RF forest soils, suggesting an ecosystem-specific climate change response. The climate change response varied by parent material, where AN soils exhibited minimal change and GR and BS soils mineralized substantially greater soil C. This study corroborates the varied response in soil C mineralization by parent material and highlights how the soil mineral assemblage and litter type may interact to control conifer forest soil C response to climate change. © Journal compilation © 2008 Blackwell Publishing.
• Rasmussen, C., & Tabor, N. J. (2007). Applying a quantitative pedogenic energy model across a range of environmental gradients. Soil Science Society of America Journal, 71(6), 1719-1729.
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  Abstract: Conceptual energy-based pedogenic models present a framework for quantitatively linking pedon energy throughflow to soil development. In this study, we utilized a quantitative pedogenic energy model (QPEM) based on rates of effective energy and mass transfer (EEMT, kJ m 2 yr-1) to the soil system to predict pedogenesis across a wide range of pedogenic environments. Our objectives were to: (i) derive a global equation for estimating EEMT; (ii) test the QPEM framework at the pedon scale across a series of environmental gradients on igneous rock residuum; and (iii) develop quantitative transfer functions between pedogenic indices and EEMT. We derived a simplified two-dimensional Gaussian expression for estimating EEMT from mean annual temperature (MAT) and mean annual precipitation (MAP) (R2 = 0.96, significant at P ≤ 0.001) using a global climate data set. Environmental gradient data indicated significant differences in EEMT between soil orders (i.e., Entisol = 14,586 vs. Ultisol = 36,521 kJ m-2 yr 1), whereas neither MAT nor MAP demonstrated significant differences among soil orders. Pedon data from the gradients were used to derive quantitative transfer functions between EEMT and pedogenic indices, including pedon depth, clay content, subsurface chemical index of alteration minus potassium (CIA-K), and the ratio of free Fe oxides to total Fe (Fe d/FeT). Significant linear and nonlinear functions were derived between EEMT and all of the pedogenic indices, whereas no significant functions could be fit between pedogenic indices, MAT, or MAP. The favorable results from this study suggest that the QPEM framework and EEMT may provide a basis for quantitative pedogenic modeling and prediction of soil properties. © Soil Science Society of America. All rights reserved.
• Rasmussen, C., Matsuyama, N., Dahlgren, R. A., Southard, R. J., & Brauer, N. (2007). Soil genesis and mineral transformation across an environmental gradient on andesitic lahar. Soil Science Society of America Journal, 71(1), 225-237.
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  Abstract: Soils derived from andesite are regionally important in the western USA, and expression of andic soil properties may be directly related to climate. The objective of this research was to quantify mineral transformation on andesitic lahar across an environmental gradient on the western slope of the Sierra Nevada of California. We hypothesized that the dominance of short-range-order (SRO) materials would increase with increasing elevation as precipitation increased and temperatures decreased. Seven pedons were sampled across an elevation gradient (150-2800 m) having large variations in mean annual soil temperature (3-17°C) and mean annual precipitation (45-150 cm). The soil mineral assemblage was characterized by x-ray diffraction, selective dissolution, total elemental analysis, and microprobe analysis. Weathering and soil development displayed maxima in the zone just below the permanent winter snowline (∼1590 m), with a sharp decrease at higher elevations. Rainfall-dominated soils at lower elevations had a clay fraction dominated by kaolin. In the snowfall-dominated zone, SRO (allophane and imogolite) dominated the clay fraction, except for the soils in the cryic soil temperature regime, where interlayered 2:1 layer silicates dominated. The 2:1 mineral is probably inherited, based on the presence of a chlorite-like mineral in the andesite parent material. With increasing elevation, soil development followed the order Mollisols → Alfisols → Ultisols → Andisols → Inceptisols. Weathering, mineralogical transformations and soil development are limited by water availability at low elevations, whereas low soil temperature is the major limitation at high elevations. © Soil Science Society of America.
• Rasmussen, C., Southard, R. J., & Horwath, W. R. (2007). Soil mineralogy affects conifer forest soil carbon source utilization and microbial priming. Soil Science Society of America Journal, 71(4), 1141-1150.
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  Abstract: The cycling of temperate forest soil C is likely to be altered with climate change. Climate change may induce changes in forest litter that promotes priming, or enhanced decomposition of extant soil C. The effects of environmental factors such as temperature, litter quality, and soil mineralogy on priming are not well understood. The objectives of this study were to determine the interaction of temperature and soil mineral assemblage on priming of temperate forest soil C. We incubated soils from three forest types (ponderosa pine, white fir, and red fir), on granite (GR), basalt (BS), and andesite (AN) parent materials at three temperatures (12.5, 7.5, and 5.0°C), with the addition of 13C-labeled ponderosa pine litter. Soil C mineralized from each parent material differed in response to increasing temperature (i.e., relative increases of 38-70% from 5.0-12.5°C), following a pattern of GR > BS > AN. The percentage of C derived from litter and soil C pools varied significandy by parent material and forest type. Andesite soils, dominated by short-range-oder (SRO) aluminosilicates demonstrated decreased priming relative to BS and GR soils across all forest types. Soil C mineralization rate data indicated that the majority of priming effects were short term (within the first 20 d of a 90-d incubation). Regression analysis indicated control of priming by soil C, C/N, and soil C 13C signature, SRO Fe oxyhydroxides, and Al-humus complexes. Variation in the soil mineral assemblage was the dominant control of both cumulative soil C mineralization and soil C priming. © Soil Science Society of America.
• Rasmussen, C. (2006). Distribution of soil organic and inorganic carbon pools by biome and soil taxa in Arizona. Soil Science Society of America Journal, 70(1), 256-265.
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  Abstract: Arid systems represent an important component of the global soil C budget in that they cover 12% of the global land area and contain nearly 20% of global soil C stocks, both organic (SOC) and inorganic (SIC). The objectives of this study were to quantify SOC and SIC stocks in Arizona biomes, using Arizona as a model system for arid lands. Biome distribution was extracted from the Arizona Gap Analysis Project spatial vegetation dataset (GAP), while soil C date were extracted from the Arizona State Soil Geographic Dataset (STATSGO) at a scale of 1:250 000, and the western Yavapai County Soil Survey Geographic Dataset (SSURGO) at a scale of 1:24 000. Soil data were converted from a polygonal vector format to a raster format, and a raster-based method used to estimate SOC and SIC stocks by biome. Statewide, STATSGO soil C stocks indicate Arizona contains 0.5 and 1.5 Pg of SOC and SIC, respectively, with 27% of the SOC in pinyon-juniper biomes (PJ), and 34% of SIC in creosotebush-bursage biomes (CB). A comparison of soil C estimates between datasets indicates significantly greater estimates of biome SOC and SIC using SSURGO data relative to the STATSGO data. SSURGO soil C estimates varied considerably between the raster-based and soi taxa based method of data aggregation. Soil taxa data exhibited large ultra-unit variation in each biome. In addition, soil C differed substantially between biomes by soil taxa (e.g., Haplargid SOC of 40 and 13.5 kg m -2 in the paloverde-cacti (PC) and montane pine (MP) forest biomes, respectively). Raster based soil C estimations incorporate the spatial distribution and areal land cover of each soil type within a biome, providing a more accurate representation of soil C stocks. © Soil Science Society of America.
• Rasmussen, C., Southard, R. J., & Horwath, W. R. (2006). Mineral control of organic carbon mineralization in a range of temperate conifer forest soils. Global Change Biology, 12(5), 834-847.
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  Abstract: Coupled climate-ecosystem models predict significant alteration of temperate forest biome distribution in response to climate warming. Temperate forest biomes contain approximately 10% of global soil carbon (C) stocks and therefore any change in their distribution may have significant impacts on terrestrial C budgets. Using the Sierra Nevada as a model system for temperate forest soils, we examined the effects of temperature and soil mineralogy on soil C mineralization. We incubated soils from three conifer biomes dominated by ponderosa pine (PP), white fir (WF), and red fir (RF) tree species, on granite (GR), basalt (BS), and andesite (AN) parent materials, at three temperatures (12.5°C, 7.5°C, 5.0°C). AN soils were dominated by noncrystalline materials (allophane, Al-humus complexes), GR soils by crystalline minerals (kaolinite, vermiculite), and BS soils by a mix of crystalline and noncrystalline materials. Soil C mineralization (ranging from 1.9 to 34.6 [mg C (g soil C)-1] or 0.1 to .3 [mg C (g soil)-1]) differed significantly between parent materials in all biomes with a general pattern of AN
• Rasmussen, C., Southard, R. J., & Horwath, W. R. (2005). Modeling energy inputs to predict pedogenic environments using regional environmental databases. Soil Science Society of America Journal, 69(4), 1266-1274.
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  Abstract: We present a model for prediction of pedogenic environments and soil properties based on energy input to the soil system. The model estimates rates of precipitation and net primary production (NPP) energy input using the Parameter-Regression Independent Slope Model (PRISM) climate data, and a parent material index (PMI). Soil order, soil C, and clay data from the State Soil Geographic (STATSGO) database were compared with rates of NPP and precipitation energy input for major geographic regions of the continental USA, including California, Oregon, Washington, Texas, North Dakota, Alabama, Pennsylvania, and New Hampshire. Soil orders in all states show differences in total energy input (Ein, kJ m-2yr-1) and the percentage of E in from NPP (%Enpp) (e.g., Ultisols Ein = 29 915, %Enpp = 49%; Mollisols Ein = 5880, %Enpp = 90%). Using linear regression models, rates of NPP estimated (R2 = 0.82***) trends in soil C content in western states, but failed to estimate soil C in other geographic areas. Parent material index adjusted energy flux estimated soil clay content for the majority (99.5%) of igneous parent materials in California and Oregon (R2 = 0.67**), the only states with digital geologic data. The model underestimated clay content in steeply sloping Inceptisols and Andisols (0.5% of igneous land area). Results suggest that rates of NPP may be used to estimate soil C for climate regimes with steep environmental gradients. Landscape age and stability components might improve clay prediction in young and erosive landscapes. Modeled energy input provides a tool for estimating pedogenic environments, soil order, and soil properties. Energy input parameters may aid efforts to pre-map broad landscape units for soil survey. © Soil Science Society of America.
• Rasmussen, C., Torn, M. S., & Southard, R. J. (2005). Mineral assemblage and aggregates control carbon dynamics in a California conifer forest. Soil Science Society of America Journal, 69(6), 1711-1721.
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  Abstract: Uncertainty about the effects of climate change on terrestrial soil organic C stocks has generated interest in clarifying the processes that underlie soil C dynamics. We investigated the role of soil mineralogy and aggregate stability as key variables controlling soil C dynamics in a California conifer forest. We characterized soils derived from granite (GR) and mixed andesite-granite (AN) parent materials from similar forest conditions. Granite and AN soils contained similar clay mineral assemblages as determined by x-ray diffraction (XRD), dominated by vermiculite, hydroxy-interlayered vermiculite (HIV), kaolinite, and gibbsite. However, AN soils contained significantly more Al in Al-humus complexes (6.2 vs. 3.3 kg m-2) and more crystalline and short-range order (SRO) Fe oxyhydroxides (30.6 vs. 16.8 kg m-2) than GR soils. Andesite-granite pedons contained nearly 50% more C relative to GR soils (22.8 vs. 15.0 kg m-2). Distribution of C within density and aggregate fractions (free, occluded, and mineral associated C) varied significantly between AN and GR soils. In particular, AN soils had at least twice as much mineral associated C relative to GR soils in all horizons. Based on 14C measurements, occluded C mean residence time (MRT) > mineral C > free C in both soil types, suggesting a significant role for aggregate C protection in controlling soil C turnover. We found highly significant, positive correlations between Al-humus complexes, SRO Al minerals, and total C content. We suggest that a combination of aggregate protection and organo-mineral association with Al-humus complexes and SRO Al minerals control the variation in soil C dynamics in these systems. © Soil Science Society of America.

Proceedings Publications

• Pries, C. H., Heckman, K. A., Crow, S. E., Fromm, S., Hoyt, A., Lawrence, C. R., Rasmussen, C., Stoner, S., & Shi, Z. (2020). Climate, land cover, and parent material drive global patterns of soil C partitioning and persistence. In AGU Fall Meeting 2020.
• Beem-Miller, J., Rasmussen, C., Schrumpf, M., Guggenberger, G., & Trumbore, S. (2019). Decadal cycling of mineral-associated soil carbon. In AGU Fall Meeting 2019.
• Dixon, T. H., Figueiredo, P. M., Owen, L. A., Rasmussen, C., Wetmore, P., & Xie, S. (2019). KINEMATIC MODELS FOR THE DEVELOPMENT OF THE EASTERN CALIFORNIA SHEAR ZONE, MOJAVE DESERT. In GSA Annual Meeting in Phoenix, Arizona, USA-2019.
• Espinosa, N. J., Moore, D. J., Rasmussen, C., Fehmi, J. S., & Gallery, R. E. (2019). Buried woodchips or biochar as a means of soil productivity and carbon restoration: Effects on microbial activities, soil carbon cycling and plant cover in a semiarid ecosystem. In AGU Fall Meeting 2019.
• Figueiredo, P., Wetmore, P., Rasmussen, C., Owen, L. A., Votor, A., & Dixon, T. H. (2019). Long Term Slip Rate of Camp Rock Fault (Eastern California Shear Zone) and Implications for the Regional Understanding of Geological Rates. In AGU Fall Meeting 2019.
• McKellar, T., Crimmins, M., Schaap, M. G., Rasmussen, C., & Ferre, T. P. (2019). Using HYDRUS Soil Moisture Modeling to Improve Drought Index Usage on Arizona’s Rangelands. In AGU Fall Meeting 2019.
• Rasmussen, C., Shepard, C., Ma, L., & Tabor, N. J. (2019). A PEDOGENIC RECORD OF ENVIRONMENTAL CHANGE IN THE UPPER SAN PEDRO RIVER BASIN. In GSA Annual Meeting in Phoenix, Arizona, USA-2019.
• Shepard, C., Rasmussen, C. -., Crimmins, M. A., & Schaap, M. G. (2013, Fall). Soil modulation of ecosystem response to climate forcing across the Desert Southwest. In American Geophysical Union Fall Meetings.

Presentations

• Beem-Miller, J., Hoyt, A., Schrumpf, M., Guggenberger, G., Rasmussen, C., & Trumbore, S. (2021, December). B32D-07 - Parent Material and Climate Interact to Control Soil Carbon Dynamics on Timescales from Years to Centuries. American Geophysical Union Annual Meeting 2021.
• Tfaily, M., Rasmussen, C., Saez, A. E., Field, J., Barberan, A., Gornish, E., Babst-Kostecka, A., Rathke, S., & Blankinship, J. (2021). Mitigating dust pollution for climate-resilience development in arid regions. Arizona Institutes for Resilience.
• Rasmussen, C., Schaap, M. G., McKellar, T., & Crimmins, M. A. (2018, January). Tracking drought across the SW in a changing climate. Climate Assessment for the Southwest Seminar Series. Tucson, AZ: CLIMAS.
• Crimmins, M. A., McKellar, T., Rasmussen, C., Schaap, M. G., & Ferguson, D. B. (2017, September). Evaluating Existing and Developing New Drought Indices Using Modeled Soil Moisture Time Series. Climate Assessment for the Southwest - New Project Showcase. Tucson, AZ: Climate Assessment for the Southwest.
• Ferguson, D. B., Rasmussen, C., Schaap, M. G., McKellar, T., & Crimmins, M. A. (2017, March). Evaluating drought indices using modeled soil moisture time series. Climate Assessment for the Southwest Spring Meeting. Tucson, AZ: Climate Assessment for the Southwest.
• Ferguson, D. B., Schaap, M. G., Rasmussen, C., McKellar, T., & Crimmins, M. A. (2017, September). Evaluating Existing and Developing New Drought Indices Using Modeled Soil Moisture Time Series. Climate Assessment for the Southwest - New Project Showcase. Tucson, AZ: Climate Assessment for the Southwest.
• Shepard, C., Pelletier, J. D., & Rasmussen, C. (2017, October). A Humped Clay Production Model. 2017 Soil Science Society of America Meetings. Tampa, FL: Soil Science Society of America.
• Bryan, M., Alyssa, W., Ben, P., Andres, S., Dawson, F., Mcintosh, J. C., Pelletier, J. D., Gallery, R. E., Rasmussen, C., & Chorover, J. D. (2016, Winter). Coring the deep Critical Zone in the Jemez River Basin Critical Zone. 2016 American Geophysical Union Annual Meeting. San Francisco CA: American Geophysical Union.
• Dawson, F., Christopher, S., Margretta, M., Rasmussen, C., Chorover, J. D., Virginia, R., & Gallery, R. E. (2016, July). Microbial biogeochemistry at the Jemez River Basin Critical Zone Observatory. Invited Speaker: Aqua Diva CZO. Jena, Germany. Jena, Germany: Jena, Germany.
• Mcintosh, J. C., Xavier, Z., Rasmussen, C., Paul, B. D., Gallery, R. E., Pelletier, J. D., & Chorover, J. D. (2016, Winter). Changing Energy Inputs at Earth’s Surface Translates to Differences in Water Availability, Weathering Rates, and Biotic Activity at Depth. 2016 American Geophysical Union Annual Meeting, Union Session. San Francisco CA: American Geophysical Union.
• Mcintosh, J. C., Xavier, Z., Rasmussen, C., Paul, B. D., Gallery, R. E., Pelletier, J. D., & Chorover, J. D. (2016, Winter). Changing Energy Inputs at Earth’s Surface Translates to Differences in Water Availability, Weathering Rates, and Biotic Activity at Depth. 2016 American Geophysical Union Annual Meeting. San Francisco CA: American Geophysical Union.
• Rasmussen, C. (2016, Nov). Is Clay-Bound Soil Organic Carbon Vulnerable to Priming?.. Soil Science Society of America Annual Meetings. Phoenix: Soil Science Society of Americ.
• Rasmussen, C. (2016, Nov). Soil Processes in the Southwestern United States. Soil Science Society of America Annual Meetings. Phoenix: Soil Science Society of Americ.
• Rasmussen, C. (2016, Nov). Using Energy and Mass Transfer to Model Pedogenic Environments and Process. Soil Science Society of America Annual Meetings. Phoenix: Soil Science Society of Americ.
• Rasmussen, C. (2016, Winter). B22B-05 Beyond clay - using selective extractions to improve predictions of soil carbon content. 2016 American Geophysical Union Annual Meeting. San Francisco CA.
• Rasmussen, C. (2015, Fall). Environmental pedology - at the interface of environmental forcing, biogeochemistry, and landscape evolution. Invited talk to the Department of Geosciences and Geophysics at University of Utah.
• Rasmussen, C. (2015, Fall). Right Beneath Our Feet: Discover the Wonders of Soil. UA Science Cafe. Magpie's Pizza, 4th Avenue.
• Regmi, N., & Rasmussen, C. (2015, June). Mapping Soil-landscape Relations in Barry M. Goldwater Range West: Yuma, AZ. 11th Conference on Military Geoscience, 15-19. Annapolis, MD.
• Shepard, C., Schaap, M. G., & Rasmussen, C. (2015, Nov.). Using Probability Distributions to Quantify Soil Development Variability with Time.. 2015 Soil Science Society of America Annual Meeting. Minneapolis, MN: Soil Science Society of America.
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  Chris won the best oral presentation award for the Pedology division.
• Chorover, J. D., Chorover, J. D., Pelletier, J. D., Pelletier, J. D., Breshears, D. D., Breshears, D. D., Mcintosh, J. C., Mcintosh, J. C., Rasmussen, C., Rasmussen, C., Brooks, P. D., Brooks, P. D., Barron-Gafford, G. A., Barron-Gafford, G. A., Gallery, R. E., Gallery, R. E., Ferre, P. A., Ferre, P. A., Meixner, T., , Meixner, T., et al. (2014, September). The Catalina-Jemez CZO: Transformative Behavior of Energy, Water and Carbon in the Critical Zone II. Interactions between Long and Short Term Processes that Control Delivery of Critical Zone Services.. National Critical Zone Observatory All-Hands Meeting.
• Finley, B., Dijkstra, P., Hungate, B., Rasmussen, C., Schwartz, E., & Mau, R. (2014, December). Soil Mineralogy and Substrate Quality Effects on Microbial Priming. American Geophysical Union.
• Rasmussen, C. (2014, December). Soil carbon stabilization in western US conifer forests – A dynamic interaction of minerals, fire, and erosion. Invited speaker at American Geophysical Union meetings.
• Rasmussen, C. (2014, May). Environmental Soil Science - At the interface of environmental forcing, biogeochemistry, and landscape evolution. Invited talk at University of California, Riverside.
• Rasmussen, C. (2014, May). Soil formation as a coupled biogeochemical process. Invited talk at UC Riverside.
• Rasmussen, C. (2014, November). Quantifying topographic and vegetation effects on the transfer of energy and mass transfers to the critical zone. Invited speaker at Geological Society of America Meetings.
• Rasmussen, C. (2014, November). Using Pedologic Information to Understand Ecosystem Response to Change. Invited speaker at the Soil Science Society of America meetings.
• Rasmussen, C. (2014, October). Soil carbon stabilization in western US conifer forests – A dynamic interaction of minerals, fire, and erosion. Invited speaker at the Norwegian University of Life Sciences.
• Lybrand, R., & Rasmussen, C. -. (2013, Fall). Climate and Topographic Controls On Soil Development Along An Environmental Gradient in the Santa Catalina Mountains, Arizona. Soil Science Society of America Meetings, Tampa Bay, Florida.
• Lybrand, R., & Rasmussen, C. -. (2013, Summer). Climate and Topographic Controls on Soil Organic Carbon Cycling in Southern Arizona, USA. Goldschmidt, Florence, Italy.
• Naumann, T., Thompson, J., & Rasmussen, C. -. (2013, Fall). Semi-Automated Disaggregation of Conventional Soil Maps Using Random Forests, DEMs and ASTER Satellite Imagery in the Sonoran Desert. Soil Science Society of America Annual Meetings, Tampa Bay Florida.
• Rasmussen, C. -. (2013, Fall). Minerals and Fire: Controls On Soil Carbon Storage in Western Conifer Forests. Soil Science Society of America Meeting, Tampa Bay, Florida.
• Rasmussen, C. -. (2013, Fall). Using statistical methods to quantify and predict catchment scale soil variability. AGU Chapman Conference onSoil-mediated Drivers of Coupled Biogeochemical andHydrological Processes Across Scales.
• Chorover, J., Troch, P., Pelletier, J., Rasmussen, C., Brooks, P., McIntosh, J., Breshears, D., Huxman, T., Papuga, S., Lohse, K., Meixner, T., Schaap, M., Litvak, M., Harpold, A., Perdrial, J., & Durcik, M. (2011, January). Carbon, water and weathering limitations in the semi-arid critical zone. 2011 Fall Meeting. San Francisco, Calif: AGU.
• Heckman, K., Knicker, H., Throckmorton, H., Welty-Bernard, A., Clingensmith, C., Horwath, W., Schwartz, E., & Rasmussen, C. (2011, January). The Influence of Soil Mineral Assemblage On Organic Carbon Cycling In a Lithosequence of Temperate Forest Soils: From the Molecular Scale to the Pedon Scale. 2011 SSSA meetings. San Antonio, TX.
• Levi, M., Rasmussen, C., & Schaap, M. (2011, January). Unraveling the Spatial Complexity of Soil Hydraulic Properties in Semiarid Ecosystems. 2011 Fall Meeting. San Francisco, Calif: AGU.
• Levi, M., Rasmussen, C., & Starman, N. (2011, January). Spatial Prediction Models of Physical Soil Properties In Southern Arizona. 2011 SSSA meetings. San Antonio, TX.
• Levi, M., Starman, N., & Rasmussen, C. (2011, January). Pre-Mapping Techniques for Soil Survey Application Using Definiens Developer. 2011 National Cooperative Soil Survey National Conference. Asheville, North Carolina.
• Lybrand, R., & Rasmussen, C. (2011). Quantifying elemental compositions of primary minerals from granitic rocks and saprolite within the Santa Catalina Mountain Critical Zone Observatory. AGU Fall Meeting. San Francisco, California.
• Lybrand, R., & Rasmussen, C. (2011, January). Chemical Weathering of Granitic Soils In the Santa Catalina Mountains, Arizona: Effects of Climate and Landscape Position. 2011 SSSA meetings. San Antonio, TX.
• Porter, C., McIntosh, J., Derry, L., Meixner, T., Chorover, J., Rasmussen, C., Brooks, P., & Perdrial, J. (2011, December). Determining solute inputs to soil and stream waters in a seasonally snow-covered mountain catchment in northern New Mexico using Ge/Si and 87Sr/86Sr ratios. AGU Fall Meeting. San Francisco, California.
• Rasmussen, C. -. (2011, January). 75 Years of the SSSA While Looking Toward the Future. 2011 SSSA meetings. San Antonio, TX.
• Rasmussen, C. -. (2011, January). Critical Zone Processes at Multiple Scales. 2011 Goldschmidt Conference. Prague, Czech Republic.
• Rasmussen, C. -. (2011, January). Invited seminar speaker at the Deaprtment of Biosystems Engineering and Soil Science, University of Tennessee Knoxville. Knoxville, TN: Department of Biosystems Engineering and Soil Science, University of Tennessee Knoxville.
• Rasmussen, C. -. (2011, January). Invited seminar speaker at the Department of Crop and Soil Sciences, University of Georgia Athens. Athens, GA: Department of Crop and Soil Sciences, University of Georgia Athens.
• Rasmussen, C. -. (2011, January). Invited seminar speaker at the Department of Earth and Environmental Science, University of PennsylvaniaDepartment of Earth and Environmental Science, University of Pennsylvania.
• Rasmussen, C. -. (2011, January). Invited seminar speaker at the Department of Soil Science, University of Wisconsin Madison. Madison, WI: Department of Soil Science, University of Wisconsin Madison.
• Rasmussen, C. -. (2011, January). Invited speaker at NSF program review of the Critical Zone Observatory Program. Critical Zone Observatory Program. Arlington, VA.
• Rasmussen, C. -. (2011, January). Invited speaker at the Global Soil Change Workshop. Global Soil Change WorkshopDuke University.
• Rasmussen, C. -., Crouvi, O., Pelletier, J., & Rasmussen, C. (2011, January). Predicting soil thickness and dust content in upland watersheds of the Mojave Desert. 2011 Fall Meeting. San Francisco, Calif: AGU.
• Starman, N., Levi, M., & Rasmussen, C. (2011, January). Predictive soil mapping in southern Arizona. 2011 National Cooperative Soil Survey National Conference. Asheville, North Carolina.
• Welty-Bernard, A., Heckman, K., Vazquez, A., Rasmussen, C., Chorover, J., & Schwartz, E. (2011, January). Microbial Composition in Decomposing Pine Litter Shifts in Response to Common Soil Secondary Minerals. 2011 Fall Meeting. San Francisco, Calif: AGU.

Poster Presentations

• Ledesma, J., Babst-Kostecka, A., Maier, R. M., Neilson, J. W., & Rasmussen, C. (2021, November). Effects of Long-Term Stockpiling on Soil Quality and Potential for Mine Site Reclamation in Semi-Arid Regions. 2021 ASA, CSSA, SSSA INTERNATIONAL ANNUAL MEETING. Salt Lake City, UT.
• Rasmussen, C. (2021, November). Paleoclimatic Constraint on the Timing of Soil Horizon Development in Southern Arizona. 2021 ASA, CSSA, SSSA INTERNATIONAL ANNUAL MEETIN. Salt Lake City, UT.
• Windingstad, J., & Rasmussen, C. (2021, November). Trends in Clay Mineralogy across an Alluvial Fan Chronosequence in the Sonoran Desert, AZ. 2021 ASA, CSSA, SSSA INTERNATIONAL ANNUAL MEETING. Salt Lake City, UT.
• Bradley, R., Fehmi, J. S., Rasmussen, C., & Arnold, A. E. (2020, July). Are symbionts of invasive grasses a key to their ecological dominance in grasslands of southern Arizona?. Mycological Society of America Annual Meeting. online: Mycological Society of America.
• Espinosa, N., Moore, D. J., Rasmussen, C., Fehmi, J. S., & Gallery, R. E. (2019, Fall). Buried woodchips or biochar as a means of soil restoration: Effects on microbial activities, soil carbon cycling and plant cover in a semiarid ecosystem. AGU annual meeting. San Francisco, CA: American Geophysical Union.
• Ferre, P. A., Rasmussen, C., Schaap, M. G., Crimmins, M. A., & McKellar, T. (2019, December). Using HYDRUS Soil Moisture Modeling to Improve Drought Index Usage on Arizona’s Rangelands. American Geophysical Union Annual Meeting. San Francisco, CA: American Geophysical Union.
• Shepard, C., Pelletier, J. D., Schaap, M. G., & Rasmussen, C. (2018, December). Signatures of obliquity and eccentricity in soil chronosequences. American Geophysical Union Annual Meetings.
• Shepard, C., Pelletier, J. D., Schaap, M. G., & Rasmussen, C. (2018, November). OBLIQUITY AND ECCENTRICITY SIGNALS FOUND IN A META-ANALYSIS OF SOIL CHRONOSEQUENCES. Geological Society of America Annual Meetings.
• Fischer, A., Shepard, C., & Rasmussen, C. (2017, Fall). GEOCHEMICAL DIFFERENCES IN PETROCALCIC AND CALCIC HORIZONS DUE TO SOIL PARENT MATERIAL IN SOUTHEASTERN ARIZONA. 2017 Geological Society of America Meetings. Seattle, WA: Geological Society of America.
• Gallery, R. E., Rasmussen, C., Fehmi, J. S., & Espinosa, N. (2017, Dev). Microbial Community Activity And Plant Biomass Are Insensitive To Passive Warming In A Semiarid Ecosystem. American Geophysical Union (AGU). New Orleans, LA: AGU.
• Mahan, S. A., Sammeth, D., Rasmussen, C., & Gray, H. (2017, Fall). ALLES CALDERA, NEW MEXICO, USA: DATING AND DEFINING THE RATE OF FORMATION OF SOILS AND WILDFIRE ACTIVITY USING LUMINESCENCE. 2017 Geological Society of America Meetings. Seattle, WA: Geological Society of America.
• Troch, P. A., Zeng, X., Wang, Y., Van Haren, J. L., Tuller, M., Sibayan, M., Schaap, M. G., Saleska, S. R., Ruiz, J., Rasmussen, C., Pelletier, J. D., Niu, G., Monson, R. K., Meredith, L., Alves Meira Neto, A., Matos, K. A., Maier, R. M., Kim, M., Hunt, E. A., , Harman, C. J., et al. (2017, December). Controlled Experiments of Hillslope Co-evolution at the Biosphere 2 Landscape Evolution Observatory: Toward Prediction of Coupled Hydrological, Biogeochemical, and Ecological change. AGU International Annual Meeting. New Orleans, LA: American Geophysical Union (AGU).
• Bryan, M., Alyssa, W., Ben, P., Andres, S., Dawson, F., Mcintosh, J. C., Pelletier, J. D., Gallery, R. E., Rasmussen, C., & Chorover, J. D. (2016, Winter). Coring the deep Critical Zone in the Jemez River Basin Critical Zone. 2016 American Geophysical Union Annual Meeting. San Francisco CA: American Geophysical Union.
• Espinosa, N., Moore, D. J., Fehmi, J. S., Rasmussen, C., & Gallery, R. E. (2016, Winter). Effect of coarse woody debris on microbial activity in a semiarid ecosystem. 2016 American Geophysical Union Annual Meeting. San Francisco CA.
• Rasmussen, C. (2016, Nov). Distribution of Perylenequinone Pigments in Several Soils in the United States. Soil Science Society of America Annual Meetings. Phoenix: Soil Science Society of Americ.
• Rasmussen, C. (2016, Nov). Paleoclimatic Constraint on Soil Formation and Survival. Soil Science Society of America Annual Meetings. Phoenix: Soil Science Society of Americ.
• Rasmussen, C. (2016, Nov). The Role of Dust on the Development of Granitic Soils in Southern Arizona. Soil Science Society of America Annual Meetings. Phoenix: Soil Science Society of Americ.
• Caylor, E., Dhakal, P., & Rasmussen, C. (2015, FAll). EP31B-1000: Lithologic Control on Secondary Clay Mineral Formation in the Valles Caldera, New Mexico. AGU 2015 Fall Meeting. San Francisco.
• Espinosa, N., Moore, D. J., Rasmussen, C., Fehmi, J. S., & Gallery, R. E. (2015, Nov). Some like it hot: soil extracellular enzyme activity and respiration are unresponsive to warming treatments in two semi-arid soils. Institute of the Environment (IE) GradBlitz. Tucson, AZ.
• Gebhardt, M., Fehmi, J. S., Rasmussen, C., & Gallery, R. E. (2015, Dec). Soil degradation and amendment effects on soil properties, microbial communities, and plant growth. American Geophysical Union Fall Meeting. San Francisco, CA.
• Rasmussen, C., & Regmi, N. (2015, Fall). Mapping soil-landscape relations in Barry M. Goldwater Range West, Yuma, AZ,. National Cooperative Soil Survey Meeting. Duluth, MN: NRCS.
• Regmi, N., & Rasmussen, C. (2015, Fall). EP31B-1007 MODELING SOIL-LANDSCAPE RELATIONS IN THE SONORAN DESERT, ARIZONA, USA. AGU Fall Meeting. San Francisco.
• Regmi, N., & Rasmussen, C. (2015, Spring). Predictive soil mapping in Barry M. Goldwater Range, Yuma, AZ,. DOD SERDP Climate Change Impacts and Adaptation Workshop,. Gila Bend, AZ.
• Shepard, C., Schaap, M. G., & Rasmussen, C. (2015, Fall). EP31B-1009 Probabilistic modeling of soil development variability with time. AGU Fall Meeting. San Francisco.
• Shepard, C., Shepard, C., Schaap, M. G., Schaap, M. G., Rasmussen, C., & Rasmussen, C. (2015, Fall). Probabilistic modeling of soil property variability with time. CALS Research Forum. UA.
• Frost, G. L., Fehmi, J. S., Rasmussen, C., & Gallery, R. E. (2014, October). Feedbacks between plant biomass and soil microbial activity in a field-based experimental warming treatment. Research Insights in Semiarid Ecosystems RISE. Tucson, Arizona.
• Frost, G., Fehmi, J. S., Rasmussen, C., & Gallery, R. E. (2014, November). Feedbacks Between Plant Biomass and Soil Microbial Activity in a Field-based Experimental Warming Treatment. Environmental Grad Blitz. Tucson, AZ: Institute of the Environment.
• Frost, G., Fehmi, J. S., Rasmussen, C., & Gallery, R. E. (2014, November). Mineland revegetation: plant biomass and soil microbial activity in a field-based experimental warming treatment. CALS poster forum. Tucson, AZ.
• Gebhardt, M. M., Fehmi, J. S., Rasmussen, C., & Gallery, R. E. (2014, November). Soil Treatment Effects on Microbial Activity and Nutrient Cycles in Semiarid Environment. Environmental Grad Blitz. Tucson, AZ: Institute of the Environment.
• Rasmussen, C., & Kuklewicz, K. (2014, December). Quantifying Soil Organic Carbon Redistribution after Forest Fire using Thermal Analyses, Valles Caldera, New Mexico. American Geophysical Union.
• Shepard, C., Holleran, M., Lybrand, R., & Rasmussen, C. (2014, December). Three-dimensional prediction of soil physical, chemical, and hydrological properties in a forested catchment of the Santa Catalina CZO. American Geophysical Union.
• Toledo, A., Heckman, K., Rasmussen, C., Harden, J., Johnson, M., & Swanson, C. (2014, December). Assessing the Influence of Mineral Surface Chemistry on Soil Organic Matter Stability in the US in Response to Climate Change. American Geophysical Union.
• Breshears, D. D., Field, J. P., Law, D. J., Brooks, P. D., Chorover, J. D., Pelletier, J. D., Troch, P. A., Lopez Hoffman, L. -., Rasmussen, C. -., Papuga, S. A., Barron-Gafford, G. A., Mcintosh, J. C., Harpold, A., Biederman, J. A., & Litvak, M. (2013, October 2013). Bridging from soil to ecosystem goods and services provided by the Critical Zone. AGU Chapman Conference: Soil-mediated drivers of coupled biogeochemical and hydrological processes across scales. Tucson.
• Gebhardt, M., Fehmi, J. S., Rasmussen, C. -., & Gallery, R. E. (2013, Oct). Soil biotic indicators for improving native plant establishment in disturbed southwestern grasslands.. 10th Annual RISE symposium. Tucson, AZ.
• Gebhardt, M., Fehmi, J. S., Rasmussen, C. -., & Gallery, R. E. (2013, Oct). Soil biotic indicators for improving native plant establishment in disturbed southwestern grasslands.. AGU Chapman Conference. BioSphere II, Tucson, AZ: AGU.
• Kwicien, A., Kwicien, A., Predick, K. I., Predick, K. I., Archer, S. R., Archer, S. R., Rasmussen, C. -., Rasmussen, C. -., Gallery, R. E., & Gallery, R. E. (2013, October). Mesquite and cactus abundance on a grazed and protected Sonoran Desert grassland site. Research Insights in Semi-Arid Ecosystems (RISE) Symposium. University of Arizona: SNRE and USDA ARS.

Others

• Rasmussen, C. (2016, Nov). Two Day Tour--Desert Pedology: Tucson to Phoenix AZ Sonoran Desert Landscapes and Watersheds. Soil Science Society of America Annual Meetings.
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  I planned and led a 2-day field trip looking at soils and landscapes around southern Arizona for 60 people. This included publication of an extensive field guide.
• Harman, C., Troch, P., Pelletier, J., Rasmussen, C., & Chorover, J. (2012, January). Critical zone evolution and the origins of organised complexity in watersheds. EGU General Assembly Conference Abstracts 14, 12310.
  More info

  Exact Date: 01/01/2012
• Rasmussen, C. -. (2012, January). Invited departmental and teaching at the Department of Natural Resources and the Environment seminar to the University of New Hampshire.
  More info

  Exact Date: 01/01/2012