Emerging technologies for in situ measurement of soil carbon

Carbon sequestration in the terrestrial biosphere is critical to mitigating the increasing anthropogenic CO2 content of the atmosphere. However, improved efficiency of methods for soil C measurement is important to better estimate terrestrial C inventories and fluxes at a regional and global scale. Laboratory based measurement of soil C involves intensive, time consuming, and costly methodology that limits applicability for large land areas. Recently, research efforts have focused on measuring soil C in situ using a variety of methods. These methods include Laser Induced Breakdown Spectroscopy (LIBS), Inelastic Neutron Scattering (INS), near-infrared spectroscopy (NIRS), and remote sensing. Basic fundamentals of each of these in situ methods for soil C determination are presented, and the differences among the methods and their relative advantages and disadvantages are discussed.