Basic Linz-Donawitz Slag as a Liming Agent for Pastureland
1994
Rodríguez, Marta | Lopez, Felix A. | Pinto, Miriam | Balcazar, Natalia | Besga, Gerardo
Linz-Donawitz (LD) slag, a by-product of the iron and steelmaking industry (29% Ca, 5% Mg w/w) produced in large quantities in Europe, poses a substantial disposal challenge. A field assay was conducted to study whether LD slag could be used as a dolomitic liming agent for pastures. Six slag rates (0, 1000, 1500, 3000, 5000, and 7500 kg ha⁻¹), with or without NPK fertilizer, were investigated for their effects on soil properties, mineral concentrations of forage, and forage yield at Bizkaia, Spain, on a Derio silty clay soil [fine silty, mixed (acid), mesic Typic Udorthent]. The 3-yr study was done on a newly established pasture of perennial ryegrass (Lolium perenne L.), cocksfoot (Dactylis glomerata L.), and white clover (Trifolium repens L.). Slag application increased soil pH linearly, especially where fertilizer was not applied. The 7500 kg rate, without NPK fertilization, increased soil pH from 5.3 to 6.5. When 3000 kg ha⁻¹ of slag was applied, the increase in soil pH was accompanied by a decrease of AI saturation percentage in the cation exchange complex, to <10%. At this rate, exchangeable Ca and Mg increased in comparison with the control, by a factor of 1.8 and 2.3, with and without fertilization, respectively. Slag application resulted in higher Ca, Mg, and P, lower K and Mn plant concentrations, and increased herbage yield. LD slag appears to be a useful liming material for correcting soil acidity on pasture soils and for increasing Ca, Mg, and P concentrations in plants.
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