@article {49998,
	title = {When bulk density methods matter: Implications for estimating soil organic carbon pools in rocky soils},
	journal = {Journal of Arid Environments},
	volume = {77},
	year = {2011},
	pages = {66-71},
	abstract = {Resolving uncertainty in the carbon cycle is paramount to refining climate predictions. Soil organic carbon (SOC) is a major component of terrestrial C pools, and accuracy of SOC estimates are only as good as the measurements and assumptions used to obtain them. Dryland soils account for a substantial portion of global SOC, but the pool dynamics are highly uncertain. One crucial component of accurate estimates of SOC on an areal basis is bulk density (p<sub>b</sub>), the mass of soil per unit volume. Here, we review methods used for calculating p<sub>b</sub> and assess their prevalence. We show how treatment of coarse fragments (particles \&gt;2 mm diameter) influences p<sub>b</sub> values and discuss the implications for SOC estimates in drylands. In four dryland examples, methods that varied in their treatment of coarse fragments led to substantial (up to 26\%) differences in p<sub>b</sub>. Calculated SOC pools responded proportionally, with SOC differing by up to 518 g C m<sup>-2</sup>. We suggest a revised method for accounting for coarse fractions in p<sub>b</sub> calculations. A large portion of the world\&rsquo;s soils, particularly in drylands, are fine enough to allow p<sub>b</sub> determination with cores, but contain coarse fragments that substantially impact SOC mass estimates if not explicitly considered.},
	doi = {doi:10.1016/j.jaridenv.2011.08.020},
	author = {Heather L. Throop and Steven R. Archer and Curtis H. Monger and S. Waltman}
}
