Effects of steel slag application on greenhouse gas emissions and crop yield over multiple growing seasons in a subtropical paddy field in China

Effect of Silicon on Crop Growth, Yield and Quality

“…Isa et al ( 2010 ) found that Si-enhanced rice growth was independent of silica deposition and suggested an important physiological role of Si in the cell wall, although they did not report any evidence. The yield responses to Si fertilization depend largely upon plant-available Si content in soil, plant-available Si content of the fertilizers used, soil pH, N application levels and other environmental factors such as climate conditions (Liang et al 1994 ;Savant et al 1997 ;Park 2001 ;Wang et al 2001Wang et al , 2014Wang et al , 2015. According to the review by Savant et al ( 1997 ), rice yield responses to Si fertilization differed greatly from one experiment to another, ranging from 4.6 to 48 %.…”

“…They showed that while steel-slag amendment had no positive effects on rice growth characteristics other than the shoot/root ratio ( P < 0.05), it signifi cantly increased the grain yield and percentage of ripened grain (Table 11.2 ). Further research showed that the yield of the fi rst early rice crop was signifi cantly higher when slag was applied at a rate of 8 Mg ha −1 than when lower rates were applied ( P < 0.05, Table 11.3 , Wang et al 2015 ), and the yield of the late rice crop with slag added at a rate of 4 and 8 Mg ha −1 was also signifi cantly higher than in the control ( P < 0.05); however, no signifi cant rice yield response was observed when steel slag was applied at a rate of 2 Mg ha −1 only ( P > 0.05). Furthermore, no signifi cant residual effects of slag application were observed on the yields of both the second early paddy and the vegetable crops, suggesting that application of slag is needed for the third crop season.…”

Effects of silicate application on CH4 and N2O emissions and global warming potentials in paddy soil under enhanced UV‐B radiation

“…13,15 Application of slag fertilizer particles decreased the bulk weight of soil, and increased the porosity, and thus possibly enhanced the oxygen inflow amount from atmospheric environment. 19 However, others reported that slag fertilizer application increased N 2 O emission 20,21 or had no effects on N 2 O emission in paddy soils. 13,16,17 In addition, silicate application promoted rice root growth, thus leading to increase in root oxygen exudation, enhancement of methanotrophic activity, depression of methanogenic activity, and reduction in CH 4 emission.…”

“…Some researchers found that adding slag silicate fertilizer decreased N 2 O emission in paddy soils. 19 However, others reported that slag fertilizer application increased N 2 O emission 20,21 or had no effects on N 2 O emission in paddy soils. 15 Silicate fertilizers include silicate fertilizers with iron (eg, slag-types) and those without iron (eg, silicate-types).…”

Microwave-Supported Leaching of Electric Arc Furnace (EAF) Slag by Ammonium Salts

“…Furthermore, the iron and steel industry is recognized as one of the largest CO 2 emission industries with total amounts of 1500~1600 Mt CO 2 emission [3]. Currently, the waste steelmaking slag are mainly used as fluxing agent of iron and steel smelting [4,5], fertilizer of agricultural production [6,7], construction materials (such as slag cement, brick, concrete and construction aggregate) [8], soil conditioner [9], as well as adsorbent of environmental protection [10]. However, for these applications only a small part of the slag can be utilized, especially in China, where the utilization rate of steel slag is only 22%, which is far behind the developed countries [11].…”