Figure 1

Change in soil organic C (tonnes C ha⁻¹) between no-till and full tillage management across depths from 0 to 80 cm over 20 years. Positive values represent more soil organic C with no-till management. Graphs include the following climatic and edaphic conditions: (A) loamy, silty and clayey (LSC) soils in tropical dry climates, (B) sandy soils in tropical dry climates, (C) LSC soils in tropical moist/wet climates, (D) sandy soils in tropical moist/wet climates, (E) LSC soils in warm temperate dry climates, (F) sandy soils in warm temperate dry climates, (G) LSC soils in warm temperate moist climates, (H) sandy soils in warm temperate moist climates, (I) LSC soils in cool temperate dry climates, (J) sandy soils in cool temperate dry climates, (K) LSC soils in cool temperate moist climates, and (L) sandy soils in cool temperate moist climates. Sandy soils contain 50% or more sand. The red lines represent the observed changes in soil organic C at the depth range of each line, the blue shading is a 95% confidence interval for the estimated change in SOC stocks, and grey vertical line denotes a depth of 30 cm. These results are based on the measured differences at each depth without adjustment for equivalent mass (See Table 1 for adjusted results).