Baseline-Dependent Responses of Soil Organic Carbon Dynamics to Climate and Land Disturbances

Table 2

The baseline SOC stocks of major land use classes and their change rates.

Land use type	Number of pixel^a			Change in pixel	SOC in 1972	1972–1998^b	SOC in 1998	1998–2007
	1972	1998	2007	1998–2007	Mg C/ha	Mg C/ha/yr	Mg C/ha	Mg C/ha/yr
Forest	275	237	297	60	74.0	−0.22	75.0	−0.02
Grassland	7344	6618	4865	−1753	81.9	−0.11	76.1	0.04
Agriculture	26327	24342	22705	−1637	86.6	−0.45	75.9	0.05
Wetland	1836	1684	3309	1625	95.9	−0.38	75.6	0.04
Mean					85.8	−0.38	75.9	0.04
Stdev					22.9	0.27	19.7	0.40

^aPixel size = 60×60 m².
^bBaseline SOC stocks in 1998 for each land use type are not necessarily associated with the calculation of annual SOC change rate for 1972–1998 because of land use change.