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Kinetics of Losses of PCNB and DCNA in Three California Soils
Author(s) -
Wang C. H.,
Broadbent F. E.
Publication year - 1972
Publication title -
soil science society of america journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.836
H-Index - 168
eISSN - 1435-0661
pISSN - 0361-5995
DOI - 10.2136/sssaj1972.03615995003600050019x
Subject(s) - muck , loam , volatilisation , fungicide , soil water , persistence (discontinuity) , environmental chemistry , chemistry , kinetics , organic matter , moisture , environmental science , soil science , agronomy , geology , organic chemistry , biology , geotechnical engineering , physics , quantum mechanics
The losses of two fungicides, PCNB (pentachloronitrobenzene) and DCNA (2,6‐dichloro‐4‐nitroaniline) in three California soils differing in their properties were measured in laboratory experiments. Under controlled temperature and moisture content, both fungicides were lost according to first‐order kinetics. The calculated half‐time ( t ½ ) was employed to indicate the stability or the persistence of the fungicides. The half‐times of PCNB were found to be 4.7, 7.6, and 9.7 months for Columbia fine sandy loam, Sacramento clay, and Staten peaty muck, respectively, while those of DCNA were 30, 16.2, and 13.6 months, respectively. Thus higher soil organic matter was associated with slower PCNB loss but enhanced DCNA loss. It was also found that clay affected losses of the fungicides in a similar way. Evidence was obtained to show that PCNB was lost mainly through volatilization whereas DCNA was lost through microbial degradation and other processes.