1Department of Agronomy, Forages and Grassland Management, College of Agriculture, CSKHPKV, Palampur-176062, Himachal Pradesh, India
2Department of Biotechnology, CSIR-Institute of Himalayan Bioresources and Technology, Palampur, Himachal Pradesh, India
3Department of Entomology, College of Agriculture, CSKHPKV, Palampur-176062, Himachal Pradesh, India
*Corresponding author: sharma_neelam29@rediffmail.com
Online published on 6 August, 2015.
A field investigation was conducted to determine dissipation behaviour in soil and terminal residues of metribuzin in potato crop applied at half the recommended dose (0.25 kg. ha−1), recommended dose (0.50 kg. ha−1) and double the recommended dose (1.00 kg. ha−1). Soil samples at different time intervals after herbicide spray and potato tuber samples at the maturity of crop were collected, processed and subjected to metribuzin residue analysis by a validated gas chromatography method with an accepted recovery of above 80%. In all herbicide treatments, more than 90% of applied herbicide in soil dissipated within 45 days after herbicide application. Metribuzin residues in potato tubers at the time of harvest were below detectable levels. This indicated that the metribuzin did not leave any residues in potato tuber at any of the applied doses. From the study, it may be concluded that pre emergence application of metribuzin in potato for weed management could be considered safe, as its residues were below the prescribed MRL (0.05 mg. kg−1).
A method for extraction and analysis (by GC) of metribuzin residues in alfisol soil and potato tuber was standardized.
Recovery efficiency of method was above 80%
Dissipation of metribuzin at all three levels of application viz. 0.25, 0.50 and 1.00 kg. ha−1 in soil fitted first order kinetics decay curve.
At the time of harvest metribuzin rsidues were below detectable level in potato tubers.
Herbicide, recovery, half life, persistence, metribuzin
