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Land Use and Management Practice Impacts on Soil Carbon and Associated Agroecosystems Services

Principal Investigator/Project Leader: 
Rachel
Hestrin
Department of Project: 
Stockbridge School of Agriculture
Project Description: 

We will use a combination of field work, greenhouse experiments, incubations, laboratory methods (including physiochemical, molecular, and spectroscopic analyses), advanced imaging, stable isotope tracing, multi-omics (DNA/RNA sequencing, metabolomics, proteomics), and computational approaches to characterize and measure soil organic matter and its dynamic interactions with the ever-changing soil environment and its inhabitants. In the near future, our work will focus on the fate of organic N inputs and their interactions with soil minerals. This mineral associated organic N pool (often referred to as MAOM-N) is a critical but overlooked component of the soil N cycle. As part of a collaborative, multi-institutional project, we will investigate the following questions:

How does the relative abundance and chemistry of MAOM control N availability?

How do MAOM-N pools and MAOM-N dynamics vary across different cropping systems and management practices?

How do roots mobilize MAOM-N?

How do these processes contribute to plant productivity, resource use efficiency, and soil C storage?

First, we will use spectroscopy (e.g., FTIR, NEXAFS), sequential extractions, elemental and chemical analyses (e.g., IRMS, TOC, TON, FTICRMS), and imaging (e.g., SEM, TEM, IR microscopy, STXM-NEXAFS) to characterize MAOM-N present in paired soil samples maintained under annual wheat (conventional tillage and fertilization) vs perennial grasslands (no tillage or fertilization). Our soil sampling sites represent a gradient of soil texture and climatic conditions. Next, we will conduct incubations and greenhouse experiments to investigate how this MAOM-N is formed, transformed, and mobilized by plants and microbes. We will use stable isotope tracing to distinguish the fate of different organic matter sources within the complex soil matrix.

Topics: 
Agriculture topics: 
Soil and Nutrient Management
Soil Health