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Effect of Soil Aeration and Phosphate Addition on the Microbial Bioavailability of Carbon‐14‐Glyphosate
Author(s) -
Kanissery Ramdas G.,
Welsh Allana,
Sims Gerald K.
Publication year - 2015
Publication title -
journal of environmental quality
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.888
H-Index - 171
eISSN - 1537-2537
pISSN - 0047-2425
DOI - 10.2134/jeq2014.08.0331
Subject(s) - bioavailability , glyphosate , aeration , phosphate , environmental chemistry , chemistry , environmental science , agronomy , biology , biochemistry , bioinformatics , organic chemistry
The adsorption, desorption, degradation, and mineralization of 14 C‐glyphosate [ N ‐(phosphonomethyl)glycine] were examined in Catlin (a fine‐silty, mixed, superactive, mesic Oxyaquic Argiudoll), Flanagan (a fine, smectitic, mesic Aquic Argiudoll), and Drummer (a fine‐silty, mixed, superactive, mesic Typic Endoaquoll) soils under oxic and anoxic soil conditions. With the exception of the Drummer soil, soil aeration did not significantly alter the adsorption pattern of 14 C‐glyphosate to soils. Herbicide desorption was generally enhanced with anaerobiosis in all the soil types. Anoxic soils demonstrated slower microbial degradation and mineralization kinetics of 14 C‐glyphosate than oxic soils in all the soil types studied. Phosphate additions significantly reduced the adsorption of 14 C‐glyphosate to soils irrespective of soil aeration and confirmed the well‐established competitive adsorption theory. The addition of soil phosphate stimulated degradation only in anoxic soils. The results from this research highlight the importance of soil redox conditions as an important factor affecting the bioavailability and mobility of glyphosate in soils.