Fig. 1. Percentage of plant C remaining based on cumulative CO₂ flux and initial C input from plant tissue. Plant tissue was incubated in soil for 498 d at 25°C and 60% water-filled pore space. Vertical bars are SE, n = 4. Predicted lines calculated using two-pool, double exponential model (Wieder and Lang, 1982): C_t = C_aexp(–k_at) + (100 – C_a)exp(–k_pt), where k_a is the decomposition rate for C_a, which represents the rapidly decomposing or active plant litter, k_p is the decomposition rate of (100 – C_a), which represents the slowly decomposing plant litter, and C_a is the percentage of C remaining in the active litter fraction, which assumes that adding plant tissue did not alter the decomposition of soil organic matter present in the soil.