Fig. 6 Linear regressions between properties of plow- (PT) or no-tillage (NT) soil samples that were incubated and leached weekly during a period of 35 d. The soil structure of the samples had been disturbed or was kept intact. The linear regressions shown are (A) the availability ratio against the soil N content; (B) the soil N content against the soil C/N ratio; and (C) the availability ratio against the soil C/N ratio