ZESZYT Nr 1/ 2009 Abstrakty Volume No. 1/2009 Abstracts |
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| 6. Influence of adjuvants on
behavior of phenmedipham in plant and soil - Mariusz Kucharski and Jerzy Sadowski Abstract. The aim of the present study was to determine the influence of an addition of adjuvants on behaviour of phenmedipham in agricultural environment – residues in soil, plant, degradation rate and leaching into the soil profile. Field experiments were conducted during a three-year-period from 2006 until 2008 on arable fields located in South-Western Poland. Chemical weed control in sugar beet was carried out by commercial formulation of phenmedipham. The herbicide was applied alone and in mixture with adjuvants (oil and surfactant). Phenmedipham residues were analysed using high performance liquid chromatography with UV detection. At lifting time, in soil samples taken from plots where phenmedipham was applied alone, the residues amounted to 0.0082–0.0128 mg kg-1. In sugar beet roots samples, the residues of phenmedipham were lower than in soil and amounted to 0.0032–0.0084 mg kg-1. The addition of adjuvants caused an increase of the active substance (a.s.) residues in soil and roots of sugar beet. The residues of phenmedipham determined in roots did not exceed acceptable values MRLs (Maximum Residue Levels). The addition of oil adjuvant reduced the degradation rate of phenmedipham in soil. No signifi cant differences were observed between degradation rates for phenmedipham applied alone and with surfactant adjuvant. The DT50 value for mixture phenmedipham + oil adjuvant was about 11 days higher in comparison with DT50 for phenmedipham applied alone and amounted 32.1 (±2.1) days. Addition of adjuvants, especially oil adjuvant, to herbicide caused the slowdown of phenmedipham leaching into soil profile. key words: adjuvant, degradation rate, herbicide, leaching, phenmedipham, residues |