Table 8: Use of pretreatment SOC baseline (1988) to determine the rate of SOC change During the first 12 years and for 24 years of tillage. A 2000 baseline was used for the last 12 years on the volumetric SOC content (Mg C ha−1 layer−1 yr−1) of the Grantsburg soil.

Tillage treatmentDepth cm1988 to 2000 tillage effect on SOC rate of change by treatment (baseline 1988)2000 to 2012 tillage effect on SOC rate of change by treatment (baseline 2000)24-year tillage effect on SOC rate of change by treatment (baseline 1988)
Mg C ha−1 layer−1 yr−1

0–15−0.14−0.04−0.09
NT15–75−0.28+0.36+0.04
0–75 (all)−0.42+0.33−0.05

0–15−0.28−0.39−0.33
CP15–75−0.40+0.25−0.08
0–75 (all)−0.68−0.14−0.41

0–15−0.70−0.09−0.39
MP15–75−0.44+0.54+0.05
0–75 (all)−1.14−0.45−0.34