Silicon nutrition of rice is affected by soil pH, weathering, and silicon fertilisation

Tavakkoli, Ehsan and Lyons, Graham and English, Peter and Guppy, Chris (2011) Silicon nutrition of rice is affected by soil pH, weathering, and silicon fertilisation. Journal of Plant Nutrition and Soil Science, 174 (3). pp. 437-446. ISSN 1436-8730

Abstract

Silicon (Si) is a beneficial element for tropical grasses such as rice (Oryza sativa) and responses to applications of Si are common on highly weathered soils. However, the importance of pH (and hence Si speciation), weathering, and fertilisation on Si uptake is still poorly understood. The responses of rice to Si fertilisation were studied in two variably weathered basalt soils (Red Ferrosol, Grey Vertosol) adjusted at different pH values (5.5–9.5) with three levels of acidulated wollastonite. Soil Si was extracted using deionised water (H2O), 0.01 M CaCl2, or 0.5 M NH4OAc. Significant increases in Si uptake and rice biomass were observed in the Red Ferrosol following fertilisation (p < 0.01). Greater biomass production was observed at lower pH, due to decreased Si sorption and higher solution Si concentrations. Silicon uptake by rice was greater at low pH, despite similar extractable Si concentrations; suggesting a relationship between Si speciation and uptake. In contrast, Si uptake and rice shoot dry matter in the less weathered Grey Vertosol were unaffected by Si fertilisation (p > 0.05) except at the highest rate and lowest pH (5.5). Solution Si concentrations were controlled by recipitation/polymerisation reactions in equilibrium with specific soil pH values rather than adsorption processes. Silicon speciation effects (monosilicic acid vs. silicate ions) were unable to be measured due to an induced phosphorus deficiency in both soils at pH values > 8.5. In conclusion, weathered soils are more responsive to Si fertilisation and Si uptake is increased at low pH.


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Item Type: Article (Commonwealth Reporting Category C)
Refereed: Yes
Item Status: Live Archive
Additional Information: © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. Permanent restricted access to paper due to publisher copyright policy.
Depositing User: Mr Ehsan Tavakkoli
Faculty / Department / School: Historic - Faculty of Engineering and Surveying - Department of Agricultural, Civil and Environmental Engineering
Date Deposited: 18 Jun 2011 12:21
Last Modified: 14 Oct 2014 00:57
Uncontrolled Keywords: silicon; pH; weathering; acidulated wollastonite; rice; fertilisation
Fields of Research (FOR2008): 05 Environmental Sciences > 0503 Soil Sciences > 050304 Soil Chemistry (excl. Carbon Sequestration Science)
Socio-Economic Objective (SEO2008): B Economic Development > 82 Plant Production and Plant Primary Products > 8204 Summer Grains and Oilseeds > 820402 Rice
Identification Number or DOI: doi: 10.1002/jpln.201000023
URI: http://eprints.usq.edu.au/id/eprint/18743

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