N represents the number of individual values for each trait in each soil and stage combination. SM: shoot mass; RM: root mass; R/S: root: shoot ratio; MRL: main root length; MRD: main root diameter; LRL: lateral root length; LRN: lateral root number. Significance levels were: * p < 0.05, ** p < 0.01, *** p < 0.001.

Table 3. Results and information of experimental treatments for present study and other studies, showing responses of root: shoot ratio or root mass ratio to (a) below-ground interaction only; (b) above-ground interaction only; and (c) below-, above-ground interactions or population density.