Effect Of Applying Slag-based Silicon Fertilizers On Yield And Quality In Cereal Crops And Its Possible Mechanisms

[Objective] In order to recycle solid waste resources and improve their utilization efficiency, in this paper we selected several different types of industrial wastes (blast furnace slag, abata slag and fly ash) and a chemical fertilizer (sodium silicate) as soil amendments to investigate their agronomic significance and environmental risks in grey desert soil..[Method] In the present study, different application rates of blast furnace slag (0,1.0,2.0,4.0,8.0 g'kg-1), abata slag (0,1.0,2.0,4.0,8.0 g·kg-1), fly ash (0,1.5,3.0,6.0,10.0 g·kg-1)and sodium silicate (0, 0.5,1.0,1.5,2.0 g·kg-1) were applied to rice(Oryza sativa L. cv. Qiutian-39) and maize(Zea mays L. cv. SC-704) grown in potted soil (grey desert soil) and parameters for photosynthesis, growth, yield and quality were determined.[Results] 1) Applying blast furnace slag, abata slag, fly ash and sodium silicate could increase soil pH value and electrical conductivity in soil grown with rice and their residual effects were significant, but at higher application rates of blast furnace slag, abata slag, and fly ash soil pH value tended to be stabilized. For sodium silicate, the soil pH and electrical conductivity was increased with increasing application rate.2) Applying blast furnace slag reduced pH value in 2009 in soil grown with maize but its residual effect led to an increase in the soil pH value in 2010; applying blast furnace slag also increased soil electrical conductivity. Applying abata slag and fly ash increased soil pH but reduced soil electrical conductivity. Applying sodium silicate increased soil pH and electrical conductivity in maize-grown soil.3) Applying blast furnace slag, abata slag and sodium silicate could improve the soil available silicon content and silicon supplying capacity, increasing the accumulation of soil available silicon. Application fly ash could improve supplying capacity and accumulation of soil available silicon.4) Applying blast furnace slag, abata slag, fly ash and sodium silicate could reduce the rice leaf angle, keeping the leaf and rice erect, and increasing net photosynthetic rate, stomatal conductance, and transpiration rate, but reducing intercellular carbon dioxide concentration in rice leaves at flowering stage.5) Applying blast furnace slag, abata slag and fly ash had no significant effect on maize leaf angle, and application of sodium silicate increased maize leaf angle.6) Applying blast furnace slag increased leaf net photosynthetic rate, stomatal conductance, transpiration rate, but reduced leaf intercellular carbon dioxide concentration in maize; However, blast furnace slag had no significant residual effect on leaf net photosynthetic rate, stomatal conductance, intercellular carbon dioxide concentration and transpiration rate in maize. Applying abata slag and fly ash increased leaf net photosynthetic rate, stomatal conductance, transpiration rate in maize, but abata slag had not significant residual effect on leaf net photosynthetic rate, stomatal conductance, intercellular carbon dioxide concentration and transpiration rate. Treatments with 3.0 and 6.0 g·kg-1 fly ash had residual effect with significant increase in leaf net photosynthetic rate, stomatal cond uctance, intercellular carbon dioxide concentration and transpiration rate in maize.7) Applying blast furnace slag increased Fe and Mn content and Ni, Fe, Mn, P, Na, Mg and K accumulation in rice; Applying abata slag increased Ca content and Se, Ni, Fe, Mn, P, Ca, Mg and K accumulation in rice; Applying fly ash increased Fe, Mn, Ca content and Ni, Fe, Mn, P and Ca accumulation; Applying sodium silicate increased P and Na content and Zn, P and Na accumulation in rice;8) Applying blast furnace slag increased Se, Fe, Mn and P content and Se, Mo, Zn, Ni, Fe, Mn, P, Na, Ca, K, Cd, and Cr accumulation in maize; Applying abata slag increased Se, Mo, Cu, Ni, Fe, Mn and P content and Se, Mo, Cu, Fe, Mn and P accumulation in rice; Applying fly ash increased Se content and accumulation in rice; Applying sodium silicate increased Se, Zn, Mn, P and Na content in rice stem. 9) Applying blast furnace slag could promote rice growth, increased rice height, number of tiller, ear length, ear weight, grain weight, shoot dry weight and yield; its residual effect could increase the rice number of tiller, grain weight, shoot dry weight and yield. Application of abata slag could promote rice growth, increased plant height, number of tiller, ear length, ear weight, grain weight, shoot dry weight and yield with its significant residual effect obtained. However, high application rates could inhibit the growth of rice and reduce the rice yield. Application of fly ash could promote rice growth, increased plant height, grain weight, shoot dry weight and yield with no significant residual effect on rice growth. Application of sodium silicate could promote rice growth, increased plant height, grain weight, shoot dry weight and yield with its significant residual effect on rice growth.10) Applying blast furnace slag could reduce maize height, but increase shoot dry weight with its significant residual effect on increasing shoot dry weight and yield. Application of abata slag could reduce plant height, but increase shoot dry weight. Its residual effect could increase maize shoot dry matter and yield. Application of 10.0 g·kg-1 fly ash could reduce plant height, shoot dry weight and yield in maize. Application of sodium silicate could reduce plant height, but increase plant growth and shoot dry matter and yield in maize (except for the treatment with 0.5 g.kg-1).11) Applying blast furnace slag increased rice starch content with its residual effect on increasing rice protein content; Applying abata slag increased rice protein content, but reduced rice starch content and water content, with its residual effect on increasing rice protein content, but with no residual effect on rice starch content and water content; Applying fly ash increased rice protein and water content, but reduced rice starch content, with its residual effect on increasing rice starch content; Applying sodium silicate increased rice protein and water content, but reduced rice starch content, with its residual effect on increasing rice protein and water content, but on reducing rice starch content.【Conclusion】1) The soil available silicon is lower in calcareous soils in semi-arid and arid zone. And supplying silicon fertilizers is needed.2) Application of silicon fertilizers could increase crop yields in calcareous soil and their residual effects were significant.3) The industrial wastes tested were proven to be used for agricultural production as silicon fertilizers or soil additives without significant environmental risks if used at a recommended rate.3)The recommended dosage of blast furnace slag, abata slag, fly ash, sodium silicate in production was 2.0g·kg-1,1.0 g·kg-1,3.0 g·kg-1,0.5g·kg-1 respectively.