Effects of experimental factors on root traits
No interaction effects of N×P, N×W and P×W were observed for total root length (TRL), root surface area (RSA), root volume (RV), root tips (RT) and root biomass (RB) of S. breviflora . The interaction effects of N×W and P×W for specific root length (SRL) were significant (P≤ 0.05, Table 3).
Meanwhile, N addition significantly affected TRL (VCR = 22.23, P< 0.01) and RT (VCR = 19.88, P < 0.001, Table 4), P addition greatly influenced RT (VCR = 22.51, P < 0.001) and water addition had significant effects on RV (VCR = 45.83,P < 0.001), RSA (VCR = 34.78, P < 0.05) and RB (VCR = 21.19, P < 0.01). In addition, cluster fragmentation was significant for TRL (VCR = 21.97, P< 0.01), RSA (VCR = 20.79, P < 0.01), RV (VCR = 17.97, P < 0.01), RT (VCR = 26.54, P< 0.001), RB (VCR = 22.81, P < 0.01) and SRL (VCR = 16.51, P < 0.01). Moreover, when considering the total VCR from each experimental factor to six root traits, water addition (Total VCR = 135.24) was the greatest contributing factor, cluster fragmentation (Total VCR = 126.59) was the second factor, followed by N addition (Total VCR = 69.54) and P addition (Total VCR = 52.22) (Table 4).