ARS | Publication request: Organic amendment effects on the transformation and fractionation of aluminum in acidic sandy soil

Submitted to: Communications in Soil Science and Plant Analysis
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: May 3, 2007
Publication Date: September 8, 2008
Citation: Vieira, F.C., He, Z.L., Bayer, C., Stoffella, P.J., Baligar, V.C. 2008. Organic amendment effects on the transformation and fractionation of aluminum in acidic sand soil. Communications in Soil Science and Plant Analysis. 39:2678-2694.

Interpretive Summary: Soil acidity is a serious constraint to crop production throughout the world. One of the main problems of acid soils is the aluminum (Al) in forms and levels that are toxic to plants and a potential risk to the environment in general, eventually to human beings. In addition to liming, organic matter application was reported to alleviate Al toxicity, thus decreasing its potential environmental risk. However, few studies has been conducted to understand the mechanisms of organic amendments in reducing Al toxicity in soil. This study was undertaken to evaluate the release and transformation of Al in an acid soil amended with organic compost. Compost amendment alleviate Al toxicity in acidic soil by converting active and exchangeable Al into organically bound Al forms, which are less toxic to plants. Findings of this research are useful for resource poor farmers of the tropics to reduce soil acidity constraints.

Technical Abstract: This study was attempted to evaluate the transformation of aluminum (Al) in an acidic sandy soil amended with composts (yard waste, yard + municipal waste, GreenEdge®, and synthetic humic acid), based on soil Al fractionation by single and sequential extraction. The compost amendment significantly increased soil pH and thus reduced active Al. The application of composts added total Al to the soils, but reduced exchangeable Al by approximately 90%. The single extraction method appeared to be more reliable than the sequential one, as it does not influence soil pH during the extraction. The amendment of composts increased organically bound Al in the soil, which is considered to be less toxic to plants than exchangeable Al. These results indicate that the compost amendment can alleviate Al toxicity in acidic soils by converting active and exchangeable Al into organically bound Al forms, which are less toxic to plants, and the single extraction method is useful for Al fractionation in soils where the participation of organic matter in Al dynamics is crucial.