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Influence of Organic Amendments on Biodegradation of Atrazine as a Nitrogen Source
Author(s) -
Alvey S.,
Crowley D. E.
Publication year - 1995
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/jeq1995.00472425002400060015x
Subject(s) - atrazine , mineralization (soil science) , chemistry , microcosm , biodegradation , compost , environmental chemistry , organic matter , nutrient , soil water , agronomy , nitrogen , pesticide , biology , ecology , organic chemistry
Carbon and N dynamics may be particularly important for selective enrichment of microorganisms that are capable of using xenobiotics as sources of N for growth. To investigate this hypothesis in relation to s ‐triazines, a soil microcosm study was performed to determine the effect of organic amendments differing in complexity and C/N ratio, and the effects of inorganic N addition on atrazine mineralization in a soil having a 15‐yr history of prior exposure to this herbicide. When the soil was spiked with 100 mg/kg of atrazine (2‐chloro‐4‐ethylamino‐6‐isopropylamino‐ s ‐triazine) in the absence of organic amendments, 73% of the atrazine was mineralized after 11 wk. Soils amended with rice hulls, starch, and compost yielded mineralization rates of 88, 75, and 59% in the same period, respectively. In contrast, <10% of the atrazine was mineralized in soils amended with glucose, Sudan hay, or sodium citrate. All treatments receiving supplemental inorganic N had a considerably lower rate of atrazine mineralization than corresponding treatments without N addition. However, the different effects of the organic matter supplements suggested there was no relationship between the C/N ratio of the soil and atrazine mineralization. An atrazine‐degrading consortium was subsequently isolated for further characterization. The results demonstrate that while atrazine mineralization is suppressed under high N conditions in this soil, the mineralization rate also is influenced by poorly understood population dynamics related to the nutrient composition and complexity of specific organic amendments.