Amelioration of Cadmium Polluted Paddy Soils by Porous Hydrated Calcium Silicate
Porous hydrated calcium silicate (PS) is a by-product of autoclave light weight concrete and is being used as a silicon fertilizer in Japan. The impacts of this amendment on the yield and cadmium content of rice (Orzya sativa L. var. Kokoromachi), soil pH and the extractability of soil cadmium assessed by 1 M NH4OAc were compared with those of silica gel and CaCO3 by pot experiments. The application of PS at the rate of 2.0% and silica gel at the rate of 1.0% in Andosol and PS at the rate of 0.75% in Alluvial soil significantly increased the grain weight of rice. PS and CaCO3 treatment significantly increased soil pH, decreased the 1 M NH4OAc extractability of cadmium and reduced cadmium content in straw and brown rice in the two soils. However, cadmium content of rice of PS treatments was not significantly different from that of CaCO3 treatments in Andosol, while was significantly lower than that of CaCO3 treatments in Alluvial soil. Soil analysis showed that it was less effective in increasing soil pH and decreasing the extractability of cadmium by 1 M NH4OAc than CaCO3 at the same application rate in Andosol. Soil pH and 1 M NH4OAc extractability of cadmium were not significantly different between 2.0% of PS and CaCO3 treatments in Alluvial soil. The application of silica gel did not improve soil pH nor decrease the extractability of soil cadmium, but resulted in a significant decline of cadmium content in brown rice. These results demonstrate that the supply of silicon together with an increase in soil pH, as obtained by PS application, shows potential to reduce the cadmium content of rice.
KeywordsPaddy soil Cadmium pollution Porous hydrated calcium silicate Rice
This work was supported in part by a Grant-in-Aid for Scientific Research from the Ministry of Education, Science, Sports, and Technology of Japan (No. 13876015).
- Asami, T. (2000). Heavy metal pollution in soils of Japan (pp. 130–138). Japan: Agune Technology Center.Google Scholar
- Cai, D. L., Chen, C. Y., & Xiao, L. J. (2000). The influence of silicon fertilizer on the Cd absorption by paddy. Areal Research and Development, 19(4), 69–73.Google Scholar
- Evans, L. J., Spiers, G. A., & Zhao, G. (1995). Chemical aspects of heavy metal solubility with reference to sewage sludge amended soils. International Journal Environmental Analytical Chemistry, 59, 291–302.Google Scholar
- Geebelen, W., Sappin-Didier, V., Ruttens, A., Robert Carleer, R., Yperman, J., Bongué-Boma, K., et al. (2006). Evaluation of cyclonic ash, commercial Na-silicates, lime and phosphoric acid for metal immobilisation purposes in contaminated soils in Flanders (Belgium). Environmental Pollution, 144, 32–39.CrossRefGoogle Scholar
- Hasegawa, E., Shima, H., Saitou, M., & Tatsuno, E. (1995).Effect of autoclaved light weight concrete on suppression of cadmium uptake by rice plants in clay paddy fields. Bulletin Miyagi Prefecture Agriculture Research Centre, 61, 13–32. In Japanese.Google Scholar
- Paulose, B., Datta, S. P., Rattan, R. K., & Chhonkar, P. K. (2006). Effect of amendments on the extractability, retention and plant uptake of metals on a sewage-irrigated soil. Environmental Pollution, xx, 1–6.Google Scholar
- Qin, S. Q., & Huang, Q. H. (1997). Effect of silicon on uptake of cadmium by rice. Xinjiang Environment Protection, 19, 51–53.Google Scholar
- Saigusa, M., Yamamoto, A., & Shibuya, K. (1998). Agricultural use of porous hydrated calcium silicate. Practical use to improve silicon nutrition of rice plants in paddy fields. Japanese Journal Soil Science Plant Nutrition, 69, 612–617.Google Scholar
- Saigusa, M., Yamamoto, A., & Shibuya, K. (2000). Change of structure of porous hydrated calcium silicate by dissolution in paddy soil. Soil Science Plant Nutrition, 46, 89–95.Google Scholar
- The Edit Committee of Soil Analysis Manual (1996). A manual for soil analysis. Tokyo: Maruzenn Kabusi Press.Google Scholar
- Yang, C. G., Dou, H., Liang, Y. C., & Lou, Y. S. (2005). Influence of silicon on cadmium availability and cadmium uptake by maize in cadmium-contaminated soil. Scientia Agricultura Sinica, 38(1), 116–121.Google Scholar
- Zhao, X. L., & Saigusa, M. (2004). Effect of porous hydrated calcium silicate on sorption and desorption of cadmium by soils. Soil Science Plant Nutrition, 50(3), 315–319.Google Scholar