drivers of soil respiration of root and microbial ... - Unitus DSpace

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Reducing this uncertainties will required more robust estimate of the pool size and rates and
fluxes through the soil C pool.
Estimates of the size of the global pool of SOC have ranged between 700 Pg (Bolin, 1970)
and 2946 Pg (Bohn, 1976), with the value of around 1500 Gt now generally accepted as the most
appropriate (Table 1).
Study Soil C (Pg)
Bolin (1970) 700
Bohn (1976) 2946
Baes et al. (1977) 1080
Basilevich (1974) 1392
Schlesinger (1977) 1456
Aitjay et al. (1979) 2070
Post et al. (1982) 1395
Eswaran et al.(1993) 1576
Batjes (1996) 1500
Jacobson et al. (2000) 1500
Table 1. Estimate of the size of the global SOC pool to 100cm.
From the understanding of the behaviour of the SOC pool, models such as Rothamsted
(Jenkinson and Rayner, 1977) and Century (Parton et al., 1993) have been developed and allow the
results from the regional validation studies to be extrapolated to a global scale (Schimel et al.,
1994). Such models divide the SOC pool into three to five pools with different turnover times
ranging from tens to thousands of years, and the sizes of these pools for a given soil texture are
determined climate-driven interactions between plant C inputs, nutrients, microbial respiration,
and leaching of dissolved organic carbon (DOC) (Fig.3).