Partitioning of ryegrass residue sulphur between the soil microbial biomass, other soil sulphur pools and ryegrass (Lolium perenne L.)

摘要: Ryegrass shoot residues, labelled with 35S, were added to an S-deficient soil. The transfer of S the microbial biomass, soil pool extractable by NaHCO3 and growing ryegrass when present was followed over 34 weeks. After 2 weeks 16% 15% residue found in biomass pool, respectively. Where plants grown, they became (shoot <0.2%) simultaneously showing a marked increase C:S ratio. This eventually reached 262 from initial value 59. Concurrently, which included some labile organic S, decreased <0.2 μg g−1 27% plant, 7% 2% pool. Some mineralization unlabelled observed during period greatest plant growth (8–14 weeks), but not absence plants. A second phase occurred between 22 34, concurrent rise mean temperature, unaffected presence or size biomass. may have been due “biochemical” ester sulphate. amount involved active cycling estimated be 11%–13% total S.