
TY  - JOUR
A1  - Santoso, D 
A1  - Lefroy, RDB 
A1  - Blair, GJ 
T1  - A comparison of sulfur extractants for weathered acid soils
JF  - Soil Research
JO  - Soil Res.
Y1  - 1995
VL  - 33
IS  - 1
SP  - 125
EP  - 133
KW  - Sulfur;Acid Soil;Soil Extractants;
UR  - https://doi.org/10.1071/SR9950125 
N2  - The increasing incidence of S deficiency throughout the world has focused attention on ways of assessing the S status of soils. An incubation experiment was conducted using three acid soils varying in S sorption capacity. The soils were a gleyed podzolic (Aquic Haplustalf), a red earth (Haplohumult) and krasnozem (Haplohumult) with a S sorption (at 5 µg S mL(-1)) of 13, 48 and 135 µg S g(-1)) soil, respectively. A factorial combination of S (0 and S applied to 5 µg S mL(-1)) in soil solution), P (0 and P applied to 0.2 µg P mL(-1)) and lime (0, 1.5 x exch. Al) was applied to the soils which were incubated at 70% of field capacity at 25°C for 3 weeks. At the end of the incubation period the soils were extracted with 0.01 M P as Ca(H2PO4)2 (MCP), water (water) and 0.01 M CaCl2 (CaCl2). The concentration of S extracted (µg S g-1) soil) varied between soils, treatments and extractants. In the krasnozem, the order was MCP > water > CaCl2. In the gleyed podzolic the amounts extracted by the three methods were similar and in the red earth the order was water > CaCl2 > MCP. The addition of P and lime affected the extractans in different ways. The use of 35S-labelled sulfate allowed a calculation of the recovery of added S and this differed between soils and extractants. The results indicate that on low S-sorbing soils the extractants used were not sensitive enough to account for differences brought about by P and liming and that care is needed in interpreting results from such experiments. 
ER  -

