Linking Water, Carbon, and Nitrogen Cycling in Soils from Local to Landscape Scales

Natural resources are most effectively managed when we understand how water, carbon (C), and nitrogen (N) content in soils vary through space and time, and what causes those changes. The amount of water, C, and N in soils is controlled by a soil’s wetness, porosity, and heterogeneity, and how those properties, in turn, impact the density and diversity of microbial communities. For this project, an interdisciplinary team of scientists will complete field, laboratory, and scaling studies to improve understanding of soil processes and ultimately how we predict, prevent, manage and remediate soil and water contamination. The project will involve undergraduate and graduate students. The outcomes include curriculum and outreach materials for science students and teachers at regional secondary schools, as well as improved pedagogy. The hypothesis-driven project will determine if soil layers, lenses and fractures are hotspots for C and N cycling. The project will also investigate if wet and dry periods in soils affect the density and diversity of microbial communities and therefore control C and N cycling. Finally, the research will explore how these two factors (soil properties and soil wetness) work together to control soil C and N content from the local to landscape scales. The project leverages ongoing monitoring and modeling at the Texas Water Observatory. Field sampling includes observations of water content, temperature, carbon, nitrogen, and microbial mRNA and DNA in soils during wet and dry conditions. Controlled laboratory experiments will be used to study layered, lensed, and fractured soil systems. The resulting data sets will be analyzed to establish relationships between hydrologic, geochemical and microbial processes at different scales and across different types of ecosystems. Overall, the outcomes of this study will lead to better management of agricultural and ecological systems. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.