Impacts of Steel-Slag-Based Silicate Fertilizer on Soil Acidity and Silicon Availability and Metals-Immobilization in a Paddy Soil.

Dongfeng Ning,Junfu Xiao,Aiwang Duan,Yongchao Liang,Zhandong Liu,Hatem Rouached

doi:10.1371/journal.pone.0168163

Dongfeng Ning, Junfu Xiao + Show 4 more

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https://doi.org/10.1371/journal.pone.0168163

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Abstract

Slag-based silicate fertilizer has been widely used to improve soil silicon- availability and crop productivity. A consecutive early rice-late rice rotation experiment was conducted to test the impacts of steel slag on soil pH, silicon availability, rice growth and metals-immobilization in paddy soil. Our results show that application of slag at a rate above higher or equal to 1 600 mg plant-available SiO2 per kg soil increased soil pH, dry weight of rice straw and grain, plant-available Si concentration and Si concentration in rice shoots compared with the control treatment. No significant accumulation of total cadmium (Cd) and lead (Pb) was noted in soil; rather, the exchangeable fraction of Cd significantly decreased. The cadmium concentrations in rice grains decreased significantly compared with the control treatment. In conclusion, application of steel slag reduced soil acidity, increased plant–availability of silicon, promoted rice growth and inhibited Cd transport to rice grain in the soil-plant system.

Highlights

Rice (Oryza sativa L.) is the second most important staple food for more than half of the world’s population [1]
Soil pH increased with increasing steel slag application rate (Fig 1)
We found that the Cd concentration in rice grain tended to decrease with increasing application rate of steel slag

Summary

Introduction

Rice (Oryza sativa L.) is the second most important staple food for more than half of the world’s population [1]. Rice is a typical Si hyper-accumulating plant species, containing Si up to 10% in shoots on a dry weight basis [2]. In tropical and subtropical areas, plant-available Si is low in these highly-weathered soil owing to heavy desilication-aluminization [7]. Repeated mono-cropping with rice greatly decrease plant-available Si in soil. Si deficiency in paddy soil has been recognized as a limiting factor for rice production [2, 8]. The need for suitable Si management to increase rice yield and sustainable productivity appears to be necessary in tropical and subtropical areas [9, 10]

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