Soil chemical characteristics, biomass production and levels of nutrient and heavy metals in corn plants according to doses of steel slag and limestone

Abstract

Steel slag presents potential for neutralizing the soil acidity instead of limestone and for supplying nutrients for plants. The objective of this work was to study the effect of steel slag on soil chemical characteristics, biomass production, and contents of nutrients and of heavy metals on dry matter of corn plants. The levels of P, K, Na, Ca, Mg, Cu, Fe, Zn, Mn, Si, Cd, Cr, Pb, and Ni were determined in steel slag and limestone (for comparison purposes) and the growth of corn plants under increasing doses of slag and limestone (0 to 10 t ha-1) was evaluated. Steel slag presented higher levels of P, Fe, Zn, Mn, and Si when compared with limestone. No difference was found in the content of heavy metals of slag and limestone, except for Cr, which was higher in the slag. Limestone provided the greatest increase of soil pH over time. Slag increased the content of P, Si, and soil micronutrient, while limestone was more efficient in increasing the content of Mg. The levels of heavy metals in the soil increased with the application of slag, but they remained below critical level within agricultural parameters. Slag and limestone presented a similar effect on the increase of the initial production of corn biomass. The levels of heavy metals in dry matter of corn plants under increasing doses of slag and limestone were below the critical levels of the toxicity of these elements on most plants.

Soil correction for planting bermudagrass using steel slag or limestone

“…However, the pH increased by 0.27 and 0.22 units with each 10% increase in base saturation, as provided by limestone and slag, respectively, reaching 6.2 and 5.7, at the desired BS of 90%. Similar results were obtained by Caetano et al (2016), who compared the use of steel slag and limestone in the cultivation of maize. Table 2.…”

“…Chemical characteristics of the soil in the 0-0.10 m layer, according to the treatment of the experiment with bermudagrass. In the two sampled layers, steel slag provided higher levels of P in the soil, at the calculated base saturations of 50%, 70% and 90%, demonstrating greater efficiency in making this nutrient available as compared with limestone, which corroborates the descriptions of Barbosa Filho et al, (2004) and Caetano et al (2016) (Tables 2 and 3). This result is related to the concentration of P found in steel slag (1.1% P 2 O 5 ).…”

“…This result is explained by its chemical composition, which is able to make silicon available to the soil when compared with limestone. According to the rates calculated to increase predetermined base saturation levels, with the use of steel slag, the soil Si levels increased linearly in both evaluated layers, corroborating the findings of Barbosa Filho et al (2004), Sobral et al (2011) and Caetano et al (2016). With the application of limestone, the Si content of the 0.0-0.10 m soil layer was not altered by base saturation.…”

“…Both correctives induced an increase in the soil Ca and Mg contents as the rates were increased, which was also observed by Nunes et al (2019). Between the correctives, limestone provided higher Mg levels in both soil layers, corroborating with Caetano et al (2016), despite the similar amounts of this nutrient in their composition. Steel slag provided the highest Ca levels at base saturations greater than or equal to 70% in the uppermost layer and, on the average of the treatments with slag, in the layer of 0.10 to 0.20 m (Tables 2 and 3).…”

Physiological, nutritional, and biochemical indicators of lead tolerance in sunflower genotypes

“…Pollution by heavy metals has become one of the major environmental issues faced by mankind (Malar et al, 2014). Environmental contamination can occur due to metallurgical, industrial, and agroindustrial activities, which may cause toxic effects on plants and animals (Bassegio et al, 2020), for example, the application of steel slag as a corrective of soil acidity can increase contents of heavy metals in soil beyond critical limits for agriculture (Caetano et al, 2016). These metal pollutants make it particularly difficult to reclaim the soil, water, and air, because, unlike an organic pollutant, which gets degraded with time into small harmless molecules, toxic elements such as lead (Pb), mercury (Hg), cadmium (Cd), copper (Cu) and zinc (Zn) are immutable by biochemical reactions (Malar et al, 2014).…”