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

• Published in: Agriculture (Basel) Vol. 11; no. 6; p. 547
• Main Authors: Gillespie, Christopher Jorelle, Antonangelo, João Arthur, Zhang, Hailin
• Format: Journal Article
• Language: English
• Published: Basel MDPI AG 01.06.2021
• Subjects: Acidic soils; Acidification; Acids; Agriculture; Alkalies; Aluminum; aluminum saturation; Aluminum sulfate; Bivariate analysis; buffer index; Calcium hydroxide; Crop yield; Crops; Cultivars; Dissolved organic carbon; Divergence; exchangeable aluminum; Fertilizers; Lime; pH effects; Phosphorus; Polynomials; Potassium; Slaked lime; Soil acidification; Soil amendment; Soil chemistry; Soil fertility; Soil lime; soil organic matter; Soil pH; Soils; Toxicity; Wheat; Winter wheat; United States > US
• ISSN: 2077-0472; 2077-0472
• DOI: 10.3390/agriculture11060547

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 < 0.0001), Stillwater was characterized by linear regression (p < 0.0001). We have reason to believe that this divergence in edaphic response might be attributed to the organically bound Al, dissolved organic carbon (DOC), spatio-temporal variance, and adsorption reactions regulated by the solubility of Al(OH)+2 species in acidic soils.