ISSN:
1365-2389
Source:
Blackwell Publishing Journal Backfiles 1879-2005
Topics:
Geosciences
,
Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
Notes:
Our aim was to study the effects of C (as glucose and artificial rhizodeposits) on S immobilization, in relation to microbial biomass-S and soil arylsulphatase (ARS) activity, in contrasting soils (a calcareous and an acid brown soil). The glucose-C and artificial rhizodeposit-C with or without cysteine were added at six rates (0, 100, 200, 400, 600 and 800 mg kg−1 soil) to the two soils and then incubated with Na235SO4 for 1 week prior to analysis. The percentages of 35S immobilized increased when C as glucose and rhizodeposit (without cysteine) were added to both soils. With cysteine-containing rhizodeposit, the percentages of 35S immobilized remained relatively stable (23.5% to 29.9%) in the calcareous soil, but decreased in the acid brown soil (52.7% to 31.5%). For both soils, cysteine-containing rhizodeposit additions showed no significant correlation between immobilized-35S and microbial biomass-35S, suggesting that microorganisms immobilized cysteine-S preferentially instead of 35S from the tracer (Na235SO4). In the calcareous soil, a positive and significant correlation was found between ARS activity and microbial biomass-35S (r = 0.85, P 〈 0.05) when glucose was added. We also saw this correlation in the acid brown soil when rhizodeposit-C without cysteine was added (r = 0.90, P 〈 0.05). Accordingly, the results showed the presence of extracellular arylsulphatase activity of 48.7 mg p-nitrophenol kg−1 soil hour−1 in the calcareous soil and of 27.0 mg p-nitrophenol kg−1 soil hour−1 in the acid brown soil.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1111/j.1365-2389.2004.00645.x
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