Fig. 1.

Schematic of field layout, showing one of the four blocks and the dimensions of one subplot. The fallow and wheat main plot treatments were continuous in the same main plots all 5 yr (not rotated). Grass crop and brassica crop subplot treatments performed poorly as intercrops, and were therefore not included in the statistical analysis.

 


Fig. 2.

Soil organic C and N concentrations in 0- to 10-cm samples taken at the end of the 5-yr treatment period. Individual replications are shown.

 


Fig. 3.

Final soil samples taken 3.5 yr after the end of the 5-yr treatment period. Samples were taken to an equivalent mass depth of 300 kg m−2 (dry soil basis) to overcome confounding of soil bulk density differences. This is equivalent to 0 to about 25 cm. These C and N concentrations can be converted to g m−2 by multiplying by 300.