Persistence of oxyfluorfen in soil and detection of its residues in rice crop

Abstract

Oxyfluorfen is a post-emergence herbicide used for control of annual and perennial broad-leaf weeds and sedges in rice. There is increasing concern about persistence of pesticide residues in soils, agricultural products and sub-sequent contamination of ground water through runoff, leaching and drift. Thus, persistence of oxyfluorfen was evaluated under field conditions in a rice cropping system. Oxyfluorfen was sprayed at 240 and 500 g ai ha⁻¹ application rates to the rice crop as post-emergence herbicide. Paddy grains, straw and soil samples were collected at harvest and analyzed for oxyfluorfen residues by HPLC. Straw samples contained 0.01 and 0.03 µg g⁻¹ oxyfluorfen residues at 240 and 500 g ha⁻¹ concentrations, respectively. In the soil, 0.028 and 0.03 µg g⁻¹ of oxyfluorfen residues were detected when applied at 240 and 500 g ai ha⁻¹, respectively. However, in rice grains, 0.018 and 0.106 µg g⁻¹ of oxyfluorfen residues were found in 240 and 500 g ai ha⁻¹ treated plots. In light of the potential adverse effects of oxyfluorfen, it is important to determine herbicide levels in these crops.

Keywords:

• soil
• rice grains
• straw
• persistence
• oxyfluorfen
• residues
• HPLC analysis

Acknowledgements

The author is greatly thankful to Director, National Research Centre for Weed Science, Jabalpur, MP, India, for providing necessary facilities to conduct the work, and Dr Anil Dixit for Agronomical trial.