Quantitative assessment of plant‐available silicon extraction methods in rice paddy soils under different management

Authors:
Publisher website
Google Scholar
Abstract
Addition of Si into paddy soil is an effective way to increase plant Si and decrease the uptake of stress‐causing metal(loids) in rice ( Oryza sativa L.). However, there are numerous methods to estimate plant‐available Si and some have limitations when Si has been applied. We evaluated four published extraction methods (1‐h CaCl 2 , 16‐h CaCl 2 , CH 3 COOH, and PO 4 ) and a 4‐h CaCl 2 extraction method. We related soil‐extractable Si to plant Si in Si‐rich rice straw and husk. Samples were collected from a 3‐yr field study in which rice was grown under a range of soil redox values (via water management) or continuously flooded and receiving different Si amendments. Straw Si concentration was a more stable measure of soil Si than husk Si concentration, regardless of the extraction method. Of the four published methods tested, the 16‐h CaCl 2 extraction explained most of the variation in straw Si concentration ( R 2  = 0.67), followed by PO 4 ( R 2 = 0.50), CH 3 COOH ( R 2  = 0.26), and 1‐h CaCl 2 ( R 2  = 0.13). The Silicate‐treated soils deviated from linear relationships with straw Si for the CH 3 COOH and PO 4 extractions. The 16‐h CaCl 2 extraction method explained over 80% of the variation in the 4‐h extraction method ( R 2  = 0.82). Moreover, the 4‐h CaCl 2 method explained nearly 60% of the variation in straw Si ( R 2 = 0.58), similar to the 16‐h CaCl 2 method. We recommend using the 4‐ or 16‐h extraction methods to assess plant‐available Si in rice paddy soil, as these perform well regardless of soil management.
Funding Information
  • National Institute of Food and Agriculture (2016‐67013‐24846)
  • Directorate for Geosciences (1350580)
  • National Science Foundation

This publication has 35 references indexed in Scilit: