
TY  - JOUR
A1  - Möller, A. 
A1  - Kaiser, K. 
A1  - Kanchanakool, N. 
A1  - Anecksamphant, C. 
A1  - Jirasuktaveekul, W. 
A1  - Maglinao, A. 
A1  - Niamskul, C. 
A1  - Zech, W. 
T1  - Sulfur forms in bulk soils and alkaline soil extracts of tropical mountain ecosystems in northern Thailand
JF  - Soil Research
JO  - Soil Res.
Y1  - 2002
VL  - 40
IS  - 1
SP  - 161
EP  - 175
KW  - transformation of soil organic matter, sulfate.
UR  - https://doi.org/10.1071/SR01001 
N2  - Sulfur, besides phosphorus, is crucial for the nutrition of plants on tropical soils. Its availability is closely related to the turnover of soil organic matter. To get a better insight into transformation of soil S forms during the decomposition of organic matter, we studied inorganic and organic S pools in bulk samples and alkaline extracts of soils under different land uses representative of the tropical highlands of northern Thailand. Samples were taken from a cabbage cultivation, a Pinus reforestation, a secondary forest, and a primary forest. Total S ranged from 483 549 mg&sol;kg in the subsoil to 1909 376 mg&sol;kg in the organic layers, which is relatively high for tropical soils. The major S component in soil was organic S, comprising 75&#8211;99&percnt; of total S. Organic S was significantly correlated with total S, organic C, and total N, indicating that there is a close relationship between C, N, and S cycling in soil. C-bonded S was the predominant form in the topsoils (35&#8211;99&percnt; of total S) but its presence decreased with soil depth. The maximum concentrations of ester SO4-S were found in the A horizons (128 49 mg&sol;kg), whereas the concentrations of inorganic SO4-S were small in all horizons. Compared with the forest site, the cabbage cultivation site was strongly depleted in S. C-bonded S was more depleted than ester SO4-S. A comparison of the S forms in NaOH extracts with S forms in bulk soil and C forms as indicated by 13C-NMR spectroscopy showed (i) that the extracts were very representative of soil organic S fractions and (ii) that ester SO4-S was mainly associated with O-substituted aliphatic C. In contrast, C-bonded S seemed to be connected to more-or-less all C binding types. transformation of soil organic matter, sulfate. 
ER  -

