Amelioration of subsoil acidity by application of a coal-derived calcium fulvate to the soil surface

Surface liming and nitrogen fertilization for crop grain production under no-till management in Brazil

“…However, organic acid anions from the soluble fraction of plant residues improve the chemical conditions of acidic soils in the relatively short term (Tang et al, 1999;Naramabuye and Haynes, 2006), while the decomposition of plant residues causes soil acidification in the long term (Caires et al, 2005(Caires et al, , 2008b. Since at least a fraction of the Ca-fulvate complex is very stable and release of Ca 2+ occurs very slowly while the complex is transported downwards into the soil profile (van der Watt et al, 1991), it is possible that the complex Ca-fulvate encourages the transport of Ca 2+ into the subsoil and contributes to alleviating the effects of acidity in deeper layers under no-till systems.…”

High clay contents, dense soils, and spatial variability are the principal subsoil constraints to cropping the higher rainfall land in south-eastern Australia

“…There is evidence to suggest that fulvic acid derived from coal, applied to the soil surface, is effective in ameliorating subsoil acidity; however, its local application requires testing (van der Watt et al 1991). Work by the Department of Agriculture in Victoria led by Ellington in the 1980s did not show any measurable benefits that could be attributed surface additions of powdered brown coal or subsoil injection of brown coal slurry (a source of fulvic acid).…”

Evaluation of Two Industrial By-products as Soil Conditioners for Reducing Potential Aluminium Toxicity and Acidity in a Palexerult of Western Spain

“…Associated with acidity, low contents of calcium and toxic concentrations of soluble and exchangeable aluminium (Al) hinder root development, causing water stress in crops and affecting nutrient root uptake ( Van der Watt et al 1991;Wright 1989;Caires et al 2008). Consequently, affected areas are at risk of being abandoned at the expense of environmental quality (Shainberg et al 1989).…”