Figure 7.Redundancy analysis of fine root traits and soil properties along rock fragment content gradient in second and third year. The proportion explained of Axis 1 and Axis 2 are 26.17% and 0.97%, respectively. Solid blue lines indicate fine root traits in each soil depth. Solid red lines indicate soil properties in each soil depth. Abbreviations for root traits are as follow: FRB, fine root biomass; RLD, fine root length density; SRL, specific fine root length; RD, fine root diameter; RTD, fine root tissue density; RFC, rock fragment content; SWC, soil water content; TC, total soil carbon; TN, total soil nitrogen; TP, total soil phosphorus; DOC, soil soluble carbon; NH4-N, soil ammonium nitrogen; NO3-N, soil nitrate nitrogen; aP, soil available phosphorus.