Soil pools of Nmin and Pex in different soil depths in relation to root biomass distribution of catch crop variants in 2 locations and years. Bubble areas represent N (green) or P (red) pool sizes and show means + s.d. (dashed lines); n = 3. Control represents fallow plots. Grey bars represent total root biomass of individual or mixed catch crop variants in different soil depths (referring to Fig. 1). Letters: Differences among soil Nmin or Pex pools within one depth according to Tukey’s test on ranks at p < 0.05; ns. = not significant.