Tracing the mineralization rates of C, N and S from cysteine and methionine in a grassland soil: A 14C and 35S dual-labelling study

Sulphur-containing amino acids (i.e. Cysteine (Cys) and methionine (Met)) constitute an important proportion of the soil organic sulphur. However, detailed information regarding microbial transformation Cys Met at a molecular level remain poorly characterized. To trace fate carbon (C) sulphur (S) derived from in agricultural grassland soil, a14C 35S dual-isotopic labelling approach was adopted. We also investigated whether their mineralization affected by manipulating C (added as glucose), nitrogen (N), phosphorus (P) S NH4NO3, KH2PO4 K2SO4) availability solution. Our results showed that over 7-day incubation period, 67.2–89.2% 14C respired 14CO2, 2.7–19.5% had been immobilized biomass; while recovery solution ranged 6.4 to 9.9%, with reminder retained biomass. Overall, our indicated communities possess high capacity utilize Met. Furthermore, using dual-labelling technique, we found were microbially mineralized different rates, indicating cycles these two elements temporally decoupled level. The addition glucose-C increased 14CO2 respiration after 7 d, comparison inorganic N, P less effect on partitioning.