ISSN 1392-3196 / e-ISSN 2335-8947
Zemdirbyste-Agriculture, vol. 106, No. 4 (2019), p. 315–320
DOI 10.13080/z-a.2019.106.040

Aluminium leaching response to acid precipitation in a lime-affected soil



Acid precipitation accelerates acidification process in the soil and facilitates nutrient leaching. The study aimed to explore the effects of long-term liming on aluminium (Al) leaching by comparing a limed soil with an unlimed soil at different acidity (pH) levels of simulated acid rain (SAR). The columns of unlimed and limed soil were watered with SAR at 5.4, 4.7 and 4.0 pH levels. Aluminium was extracted from the solid phase with the following solutions: ammonium oxalate (non-crystalline Al), sodium pyrophosphate (organically bound Al), copper chloride (organo-Al complexes of low and medium stability), lanthanum chloride (the most labile organo-Al complexes) and ammonium chloride (exchangeable Al). The total Al in the leachate was also determined. Long-term liming had a significant influence on the soil acidity and reduced all Al compounds in the in solid phase. The Al concentrations determined in the leachate of the limed soil were 0.12–0.92 mg L-1 and in that of the unlimed soil – 1.63–2.62 mg L-1. Leaching losses of Al from limed and unlimed soil increased with decreasing acidity of the simulated acid rain. The losses were found to be high when the pH of SAR was 4.0. Al in the leachate was positively correlated with all Al fractions in a solid phase and showed this to be one of the reasons for increased Al leaching from acid soils. Al leaching from the soil depended not only on the pH of simulated acid rain, but also on the soil properties: acidity, Al saturation in the exchange sites (effective cations exchange capacity) and Al compounds in the solid phase of the soil. Limed soil, characterised by a higher buffer capacity (more Ca and Mg), is able to neutralize the effects of acid precipitation and reduce the solubility of Al-containing compounds.

Key words: acid deposition, aluminium fractions, liming, soil pH, soluble Al.

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