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Occurrence of 2,4,5‐T and Picloram in Surface Runoff Water in the Blacklands of Texas
Author(s) -
Bovey R. W.,
Burnett Earl,
Richardson Clarence,
Merkle M. G.,
Baur J. R.,
Knisel W. G.
Publication year - 1974
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/jeq1974.00472425000300010017x
Subject(s) - picloram , surface runoff , agronomy , sorghum , environmental science , rangeland , pasture , vertisol , gossypium hirsutum , glyphosate , chemistry , soil water , biology , ecology , soil science
This investigation was conducted to determine the concentration of 2,4,5‐T [(2,4,5‐trichlorophenoxy)acetic acid)] and picloram (4‐amino‐3,5,6‐trichloropicolinic acid) in surface runoff water that may move from herbicide sprayed pastures and rangeland to untreated areas as a result of each major rainfall following treatment. A 1:1 mixture of the triethylamine salts of 2,4,5‐T + picloram was sprayed 5 times at 1.12 kg/ha every 6 months on a native‐grass pasture watershed. Soil, grasses and runoff water were analyzed periodically following herbicide treatment. Herbicide content in the Houston Black clay from May 1970 to May 1972 remained low (0 to 238 ppb). Herbicide content on grass was high (50 to 70 ppm) immediately after treatment, but degraded rapidly thereafter. Plant “washoff” was the main source of herbicide detected in runoff water. Concentration of herbicide was moderately high (400 to 800 ppb) if heavy rainfall occurred immediately after treatment, but low (<5 ppb) if major storms occurred 1 month or longer after treatment. No damage occurred to cotton ( Gossypium hirsutum L.) or sorghum ( Sorghum bicolor (L.) Moench) from either spray drift or subsequent runoff water in fields adjacent and below several herbicide‐treated watersheds.