The Response of Soil pH and Exchangeable Al to Alum and Lime Amendments

Abstract

Intensive cultivation and unprecedented utilization of ammoniacal fertilizer has accelerated soil acidification in the southern Great Plains and many other parts of the world. During a two-year study that evaluated the impact of soil pH and aluminum (Al) toxicity on winter wheat yield potential, we observed a variance in the edaphic responses of the two study sites (Stillwater and Chickasha) to two soil amendments, Alum [Al2(SO4)3] and lime [Ca(OH)2]. We found that AlKCl values at Stillwater were 223% and 150% higher than Chickasha during Year 1 and Year 2, respectively, with similar soil pH. Additionally, Alsat values at Stillwater were 30.6% and 24.9% higher than Chickasha during Year 1 and Year 2, respectively. Surprisingly, when treated as a bivariate of Alsat, soil buffer indices differed in graphical structure. While Chickasha was identified with a cubic polynomial (p p +2 species in acidic soils.

Keywords

• exchangeable aluminum
• aluminum saturation
• buffer index
• dissolved organic carbon
• soil organic matter