ISSN:
1432-0789
Keywords:
Lolium perenne
;
Microbial biomass
;
Mineralization
;
Plant residues
;
Ryegrass
;
Sulphur-35
;
Sulphur pools
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Geosciences
,
Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
Notes:
Summary Ryegrass shoot residues, labelled with 35S, were added to an S-deficient soil. The transfer of S to the microbial biomass, to the soil S pool extractable by NaHCO3 and to growing ryegrass when present was followed over 34 weeks. After 2 weeks 16% and 15% of the S residue was found in the biomass and in the extractable S pool, respectively. Where plants were grown, they became S-deficient (shoot S 〈0.2%) simultaneously with the biomass showing a marked increase in C:S ratio. This eventually reached 262 from an initial value of 59. Concurrently, the extractable S pool, which included some labile organic S, decreased to 〈0.2 μg g−1 soil. After 34 weeks 27% of the S residue was found in the growing plant, 7% in the biomass and 2% in the extractable S pool. Some mineralization of unlabelled soil organic S was observed during the period of greatest plant growth (8–14 weeks), but not in the absence of plants. A second phase of mineralization occurred between weeks 22 and 34, concurrent with a rise in mean temperature, which was unaffected by the presence of plants or by the size of the microbial biomass. This may have been due to “biochemical” mineralization of ester sulphate. The amount of unlabelled soil S involved in active cycling was estimated to be 11%–13% of the total soil S.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00256910
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