Fig. 3. Mean values for the carbon pools and rates of C transformations of the rototilled and control Pico silt loam soils. (a) respiration rate as measured by 1-h soil incubation, (b) MBC, (c) qCO₂, and (d) CO₂ efflux from the soil surface. The sample at 0.04 d was obtained in the field immediately after tillage, while later samples were taken from intact cores incubated in the 20°C growth chamber. The error bars are the standard error of the mean. The Least Significant Difference (LSD) based on a Student's t-test between tilled and control soil is shown