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Evaluation of two coal‐derived organic products in ameliorating surface and subsurface soil acidity
Author(s) -
NOBLE A. D.,
RANDALL P. J.,
JAMES T. R.
Publication year - 1995
Publication title -
european journal of soil science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.244
H-Index - 111
eISSN - 1365-2389
pISSN - 1351-0754
DOI - 10.1111/j.1365-2389.1995.tb01813.x
Subject(s) - lime , leachate , amendment , chemistry , leaching (pedology) , environmental chemistry , soil ph , lessivage , humus , total organic carbon , podzol , soil water , soil science , environmental science , geology , paleontology , political science , law
Summary Acidity in the soil surface and subsurface is of major concern in horticulture, cropping and pasture production systems in southern Australia. Broadcast applications of lime to the surface have proved to be ineffective in ameliorating subsurface acidity in the short term. Two calcium‐saturated coal‐derived organic products, an ‘oxi‐product’ (OXPR) and an ‘oxi‐fulvate’ (OXFU), were evaluated for use as liming materials with specific consideration given to amelioration of subsurface acidity. The effects of these two organic products and of lime on the chemical composition of the A 1 and A 2 horizons of an acid red podzol were investigated in leaching columns, 20 cm long. OXPR and OXFU supplying 80 or 160 g Ca m −2 were compared to 160 g Ca m −2 applied as CaCO 3 and a control receiving no amendments. The effects of CaCO 3 on exchangeable Al and pH were limited to the surface 2 cm. In contrast, the two organic amendments were effective in decreasing exchangeable Al and increasing pH and exchangeable Ca to depth, the extent being a function of amendment and rate applied. The formation of inorganic and organic complexes were assumed to be responsible for the movement of Al out of the column in the leachate, although significant quantities of Al were precipitated in the column. Significant linear regressions were observed between the ionic strength and Al in the leachate. Significant quantities of Mg and K were displaced by Ca and leached from the column; consequently, this loss must be considered against the benefits of decreased exchangeable Al when assessing fertility for plant production.