Flumetsulam mobility in two Mississippi soils as influenced by irrigation timing

Laboratory studies were conducted to evaluate C-14-flumetsulam mobility in two Mississippi soils of varied texture and organic matter content followin g delays in irrigation. Mobility was evaluated using packed soil columns, 2 5 cm deep, under unsaturated-saturated flow conditions. Irrigation timings included 0, 3, and 5 d after flumetsulam application. Flumetsulam mobility (defined as the amount collected in leachate) decreased from 45% to no more than 20% of the applied in the Prentiss sandy loam soil when irrigation wa s delayed 3 or 5 d. With the Okolona soil, flumetsulam recovery in the leac hate was 21, 14, and 6%, respectively when irrigation occurred 0, 3, and 5 d after application. Flumetsulam proved to be mobile when irrigation immedi ately followed application, with 6 to 45% recovered in the leachate from al l soils evaluated. The Prentiss soil retained 6% of the applied flumetsulam in the upper 5 cm and the Okolona soil retained 22% when irrigation immedi ately followed flumetsulam application. When the irrigation interval was de layed ar least 3 d, the Okolona soil retained 40% in the upper 5 cm, wherea s the Prentiss soil retained 10%. Flumetsulam mobility was dependent on irr igation timing and soil type.