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RESIDUAL ACTIVITY OF PARAQUAT IN SOILS II. ADSORPTION AND DESORPTION
Author(s) -
WATKIN E. M.,
SAGAR G. R.
Publication year - 1971
Publication title -
weed research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.693
H-Index - 74
eISSN - 1365-3180
pISSN - 0043-1737
DOI - 10.1111/j.1365-3180.1971.tb01007.x
Subject(s) - paraquat , phytotoxicity , chemistry , loam , soil water , lolium perenne , compost , germination , adsorption , agronomy , environmental chemistry , horticulture , soil science , poaceae , environmental science , biology , biochemistry , organic chemistry
Summary Glasshouse studies showed that low doses of paraquat inhibited the germination of Lolium perenne L. broadcast directly onto the paraquat‐sprayed surfaces of a sphagnum and a peat soil, but that higher doses were necessary to produce phytotoxic symptoms on mineral soils, a compost and a loam. On all soils residual activity increased rapidly with increasing dose once the minimum phytotoxic dose was reached. On a sandy soil, residual activity increased almost linearly from the lowest to the highest dose applied. At 9·0, 4·5 and 2·24 kg/ha phytotoxicity on a compost was not affected by changes in the volume of application, but at 1·68 kg/ha and lower, reducing the volume from 562 1/ha to 281 and 112 1/ha resulted in increased phytotoxicity. Phytotoxic residues were eluted from paraquat‐treated compost surfaces by percolating de‐ionized water up soil columns but residual activity was not removed from the eluted surfaces. Surface irrigation of paraquat‐treated surfaces with water previously percolated through columns of untreated soil reduced residual activity by 45%.