3.4 Relationship between root traits and soil properties
The rooting depth of the four species was negatively correlated with SWC
and nutrient content along the RFC
gradient
(P < 0.05, Fig.
6). Reductions in soil water, TC, TN and TP were the main factors
influencing the depth of the fine root profiles under high RFC
conditions (Fig. 6). Variations in SWC along the RFC gradient was the
main explanatory factor for changes in fine root traits across soil
profiles (Fig. 7 and Table S2). Fine root biomass, length density, and
specific root length all showed an increasing trend with the increase in
RFC and were significantly correlated with the decrease in both SWC and
available phosphorus (Fig. 7).