Current Research

Soil Structure and Soil Hydrology

Soil structure is the arrangement of soil particles and concomitant pores that develop in response to soil forming factors. Several projects in the lab focus on understanding how soil structure develops, how it is altered in response to environmental and land use forcings, and ways it impacts water flow into and through the soil. We examine soil structure across a variety of scales (aggregates to pedons) using both established approaches - such as detailed soil morphological descriptions, water retention, hydraulic conductivity, aggregate-size distributions, and soil moisture sensor time series - and novel 2-D imaging of thin sections and large intact soil monoliths with high-precision positioning macrophotography, multistripe laser triangulation scanning, hyperspectral imaging, and micro-XRF mapping.

Urban Soils

Urban soils are an increasingly important topical area in soil science. Although much of current urban soils work is focused on soil contamination, our lab tackles questions related to soil hydrology within the highly-variable urban soils environment where properties can change dramatically both laterally and vertically due to anthropogenic activities. Although we have been involved in projects ranging from the New York metropolitan area to São Paulo, Brazil, our focus is currently in the Greater Los Angeles area examining the potential of nature-based solutions to alter urban soil structural and hydraulic properties to optimize the capture rainfall and retention of plant-available water. As an extension of this work, we are also examining the function and life-cycles of LA bioretention basins.

Quantitative Pedology

Our lab investigates new ways of quantifying soil properties - especially morphological and related properties - that have been notoriously difficult to represent as interval or ratio data and to use these data in ways that advance our understanding of mechanisms controlling soil change as well as our ability to predict soil properties in response to future environmental conditions. Research in this area includes the development and application of horizon and profile development indices, the quantification of soil morphological properties utilizing physical methods and novel imaging techniques, integration of qualitative and quantitative variables into multivariate statistical and machine learning models, and the use of numerical modeling to simulate and predict soil change.

Arid Mountains

Arid mountains are an understudied but important component of desert environments that represent a source of alluvium for the surrounding piedmont and, less appreciated, a major sink for eolian sediment. Our lab studies these environments in California (most recently the White Mountains) to understand the effect of the interaction between dust flux, coarse fragments, carbonate accumulation, mineral weathering, and rainfall/snowfall on soil development, hydrology, and plant communities in these ranges. Our findings highlight the uniqueness of these environments and the role that they have in the overall geochemical cycling of dust in arid environments.