Pedosphere 9(1): 25--34, 1999
ISSN 1002-0160/CN 32-1315/P
©1999 Soil Science Society of China
Published by Elsevier B.V. and Science Press
| Indices of sulfur-supplying capacities of upland soils in North China |
| LIN Bao, ZHOU Wei, LI Shu-Tian and WANG Hong |
| Institute of Soil and Fertidizer, Chinese Academy of Agricultural Sciences, 30 Baishiqiao Road, Beijing 100081 (China) |
| ABSTRACT |
| Fifteen upland soils collected from the major arable areas in North China were used to assess the availability of soil sulfur (S) to plants in a pot experiment. Soils were extracted with various reagents and the extractable S was determined using turbidimetric method or inductively coupled plasma atomic emission spectrometry (ICP-AES), respectively. In addition, mineralizable organic S, organic S, N/S ratio, sulfur availability index (SAI) and available sulfur correction value (ASC) in soils were also determined. The S amount extracted by 1.5 g L-1 CaCl2 was nearly equivalent to that by 0.25 mol L-1 KCl (40 ℃), and both of them were slightly smaller than that by 0.01 mol L-1 Ca(H2PO4)2 solution, as measured by turbidimetric method or ICP-AES. The extractable S measured by turbidimetric method was consistently smaller than that by ICP-AES. All methods tested except that for organic S and N/S ratio produced satisfactory results in the regression analyses of the relationships between the amounts of S extracted and plant dry matter weight and S uptake in the pot experiment. In general, 0.01 mol L-1 Ca(H2PO4)2-extracted S determined by ICP-AES or turbidimetric method and 0.25 mol L-1 KCl (40 ℃)-extracted S determined by ICP-AES appeared to be the best indicators for evaluation of soil available S. |
| Key Words: soil available sulfur, testing methods, upland soils |
| Citation: Lin, B., Zhou, W., Li, S. T. and Wang, H. 1999. Indices of sulfur-supplying capacities of upland soils in North China. Pedosphere. 9(1): 25-34. |
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