"Release of potassium accompanying the dissolution of rice straw phytolith"

Authors: Nguyen, Minh Ngoc, Dultz, Stefan, Picardal, Flynn, Bui, Anh Thi Kim, Pham, Quang Van, Schieber, Juergen

In rice, Si assimilated from the soil solution is deposited in inter- and intracellular spaces throughout the leaf and stems to form silicified structures (so-called phytoliths). Because K is also present in significant concentrations in rice stems and leaves, the question arises if K is immobilized in the mineralized silica during the precipitation of Si. This work determined whether desilification of the phytolith is a factor regulating K release by implementing batch experiments. Solubility of Si and K of the rice straw heated at different temperatures were examined to identify effect of pretreatment. Analyses of phytoliths using SEM-EDX and X-ray tomographic microscopy in conjunction with the results from batch experiments revealed that K might co-exist with occluded organic matter inside the phytolith structure. In the kinetic experiments, corresponding increases of K and Si concentrations in the supernatants were observed which suggested that desilification of the phytolith is a main factor regulating K release. The extent of heat pretreatment of the rice straw is of significant importance with respect to dissolution of the phytolith by affecting organic removal and surface modification. At temperatures lower than 600. °C, corresponding increases of the soluble Si and K with heating temperature have been obviously observed. In contrast, the solubility of Si and K gradually decreased at temperatures above 600. °C. This work provides insights into factors that control release of K and Si from phytolith and a practical recommendation for practices of burning rice straw that may maximize subsequent release of Si and K for crops...

Title:

	Release of potassium accompanying the dissolution of rice straw phytolith
Authors:	Nguyen, Minh Ngoc Dultz, Stefan Picardal, Flynn Bui, Anh Thi Kim Pham, Quang Van Schieber, Juergen
Keywords:	Silicon Potassium Phytolith Rice straw Soil moisture chemical composition
Issue Date:	2015
Publisher:	Elsevier Ltd
Citation:	Scopus

Description:

	Chemosphere, Volume 119, 1 January 2015, Pages 371-376
URI:	http://www.sciencedirect.com/science/article/pii/S0045653514008066 http://repository.vnu.edu.vn/handle/VNU_123/34072
ISSN:	00456535
Appears in Collections:	Bài báo của ĐHQGHN trong Scopus