Fig. 1. Model II regressions between total soil organic carbon (SOC_T) and five different methods for measuring labile soil organic carbon (SOC_L): (a) light fraction C (P < 0.0005), (b) microbial C (P < 0.00001), (c) hydrolyzable C (P < 0.00001), (d) incubation labile C (P < 0.0005), and (e) Day 12 labile C (P < 0.005). All measurements were made on samples from the 0- to 10-cm soil depth.