Relationships among variables
Trait NC had negative correlations with REL RDPIs, and positive correlations with ABS RDPIs, and trait CV mainly had positive correlations with RDPIs (Fig. 2 and Table S5). These correlations decreased over time in fertile soil, and increased over time in infertile soil. Soil conditions, growth stage and population density had more significant effects on correlations between NC and ABS RDPIs, effects of growth stage and population density were more significant for correlations between CV and REL RDPIs (Table 3). For both stages, density effects on correlations between NC and RDPIs and between CV and RDPIs were more significant in fertile vs. infertile soil (Table 4 and Fig. 2).