Department of Agronomy, CCS Haryana Agricultural University, Hisar - 125004, India.
A field experiment conducted during 1991–92 and 1992–93 revealed that residual carry-over of metsulfuron-methyl after 120 days in sandy loam soil (pH 8.0)increased with corresponding increase in its concentration from 0 to 32 g/ha as indicated by the phytotoxicity on the bioassay plant onion in terms of number of leaves, shoot length and dry weight observed at 42 DAT. Persistence of herbicide was more at 25% available soil moisture (ASM) than at 75% ASM. Under 25 and 75% ASM, significant dry weight reductions were discernible at 4 and 8 g/ha dose, respectively. On the average of two years, residues of metsulfuron at4, 8, 16 or 32g/ha caused 11.8, 19.1, 35.5 or 46.5% reductions in dry weight at 25% ASM, and 4.0, 9.3, 19.6 or 31.3% at 75% ASM, respectively. Covering of the plots with black polyethylene sheets had no effect on the persistence behaviour of the chemical indicating that sunlight does not have any effect on its dissipation.
