Persistence behaviour of pretilachlor in puddled paddy fields under subtropical humid climate

Abstract

The paper delineates the field trials conducted to investigate the persistence behaviour and dissipation kinetics of pretilachlor in puddled paddy fields under subtropical humid climatic region. Matrix solid phase dispersion (MSPD) method was used for extraction of the pretilachlor from paddy grain and paddy soil samples collected from the experimental field. Pretilachlor residues were quantified using high-performance liquid chromatography (HPLC) with UV/Vis detector at 210 nm. The average recoveries of pretilachlor extracted from matrix ranged from 80.3 to 103.3% with standard deviation less than 10% and sensitivity of 0.01 μg g(-1). The dissipation rate of pretilachlor in paddy field soil and paddy field water followed first-order kinetics with decrease in pretilachlor residues as a function of time. Faster dissipation of pretilachlor was observed in paddy field water than in paddy field soil with half life of 1.89-2.97 days and 7.52-9.58 days, respectively. At harvest, the residues of pretilachlor in the paddy soil and paddy crop samples were below the detection limit.

Dissipation and fate of ready mix combination of pyrazosulfuron-ethyl and pretilachlor in rice field

“…The half-lives of pretilachlor calculated using linear equations was ranged from 5.18-6.68 days in soil and 2.59-3.00 days in field water. Similar first order kinetics for pretilachlor in rice soil was reported by Kaur et al (2015) who stated that the soil physico-chemistry, management practices and climatic conditions largely influenced the pretilachlor dissipation in rice soil and water. The half-lives of pretilachlor calculated in rice soil (5.18-5.45 days) and water (2.59-3.00 days) were in line with the findings of Fajardo et al (2009); Dharumarajan et al (2011) and Kaur et al (2015).…”

“…Similar first order kinetics for pretilachlor in rice soil was reported by Kaur et al (2015) who stated that the soil physico-chemistry, management practices and climatic conditions largely influenced the pretilachlor dissipation in rice soil and water. The half-lives of pretilachlor calculated in rice soil (5.18-5.45 days) and water (2.59-3.00 days) were in line with the findings of Fajardo et al (2009); Dharumarajan et al (2011) and Kaur et al (2015). The longer persistence of pretilachlor in soil and water than pyrazosulfuron-ethyl could be attributed to its higher sorption to soil clay particles and dissolved organic matter (Braschi et al 2003).…”

“…Before proceeding to the main residue study, the extraction method was validated by fortifying control samples of rice grain, straw, husk and soil with known concentrations (1.00, 0.50, 0.10, 0.05 and 0.01 µg/g) of pyrazosulfuron-ethyl and pretilachlor separately as described by and Kaur et al (2015). The extraction and cleanup of each herbicide was made as described in the methodology.…”

“…It quickly degrades with a half-life of 7 to 10 days in rice soil and 3.0 to 3.6 in field water (Fajardo et al 2009) by following first order dissipation kinetics. Pretilachlor degradation in soil environment was chiefly depending on soil physico-chemistry, management practices and climatic conditions (Kaur et al 2015). Pretilachlor might be toxic to aquatic organisms if the residues in crops, soil and water were above the maximum residue level (Sadeghi and Imanpoor 2013; Maryam et al 2013).…”

Dissipation Dynamic and Final Residues of Oxadiargyl in Paddy Fields Using High-Performance Liquid Chromatography-Tandem Mass Spectrometry Coupled with Modified QuEChERS Method

“…Paddy rice is a major alimentary crop that feeds over half of the world population [1,2]. Although the market production of paddy rice has increased over the years, this growth is not sufficient to cover the rapid growth of the global population [3].…”