Fig. 4. Relationships between gross amount of N mineralization during aerobic incubation for 2 wk at 30°C and indices of readily mineralizable organic N. TON: total organic N; DON: water-soluble organic N; LFN: light fraction N (r² = 0.0007, P > 0.05); KCl-N: KCl-hydrolyzable N; HCl-N: HCl-hydrolyzable N; and NaOH-N: NaOH-hydrolyzable N. r²_0.01 = 0.50 for the relationship of all measurements with gross N mineralized