Sulfometuron Persistence and Movement in Soil and Water in North Dakota

Abstract

Abstract:The lateral movement, soil persistence and aqueous hydrolysis of sulfometuron [2-([{[(4,6-dimethyl-2-pyrimidinyl) from slopes to nontarget areas was minimal and was not detected in the 0-to-30-cm-soil depth, when sampled up to 120 cm downslope from the treated area on 2, 8, or 16% slopes 1 year after treatment. The highest sulfometuron concentration found downslope from the treated area was less than 1 µg kg -1 regardless of the slope. Sulfometuron moved beyond the soil column (70 cm deep) in Fairdale loam [fine-loamy, mixed (calcareous), frigid, Mollic Udifluvents], Felor silty clay loam (fine-loamy, mixed, Typic Agriborolls), and Barnes stony loam (fine-loamy, mixed, Udic Haploborolls) soils when leached with 45.7 cm of water for 48 hours compared to only 35 to 50 cm deep when leached with the same amount of water over 9 weeks. Sulfometuron degradation increased as soil temperature and moisture increased. Sulfometuron was detected for an average of 429 days in Felor silty clay loam at pH 6.1, 8º C, and 45% field capacity but only 218 days in the same soil at 90% field capacity and 16º C. Degradation was slower in Renshaw and Sioux sandy loam [(undifferentiated soil mixture) fine-loamy over sandy or sandy skeletal, mixed Udic Haploborolls and sandy-skeletal, mixed Udortheutic Haploborollsl with a pH of 7.4 and averaged >700 days, regardless of environmental conditions. Sulfometuron hydrolysis was similar regardless of solution pH with an average of 63% 14 C-sulfometuron remaining after 28 days in water at pH 5, 7,

Best Management Practices for Silvicultural Chemicals and the Science Behind Them

“…Imazapyr is rarely detected at 50 cm, but is known to move below 30 cm in several soil types (Rahman et al, 1993). Similarly, the sulfonyl ureas (sulfometuron and metsulfuron) are known to move to 50 cm, but are not reported to move significantly below 70 cm (Walker andWelch, 1989, Lym andSwenson, 1991). In the process of movement through the soil profile, herbicides are acted upon by a variety of degradative and dilution processes.…”

Environmental Fate and Impacts of Sulfometuron on Watersheds in the Southern United States

“…Leaching of SM in agricultural and to a lesser extent forest soils has been described. Lym and Swenson (1991) did not detect SM 1.2 m downslope of treated plots with 2, 8, or 16% slopes and concluded that little lateral movement occurred in these North Dakota soils. Following addition of 45.7 cm of water over a period of 48 h in soil leaching experiments, they observed vertical movement in loamy soil columns in excess of 70 cm, but this is an extraordinary amount of water in such a short period of time and probably not representative of any actual field conditions in the USA.…”

Season-Long Dose–Response of Potato to Sulfometuron

“…In acidic environments, hydrolysis is expected to be the dominant degradation pathway of sulfometuron, whereas the herbicide is stable to hydrolysis in neutral or basic environments (Dinelli et al 1997;Montgomery 1997;Trubey et al 1998). The hydrolysis rate increases with increasing soil temperature, low pH, and the presence of adequate soil moisture (Anderson and Dulka 1985;Harvey et al 1985;Lym and Swenson 1991).…”

“…Sulfometuron was detected for an average of 429 d in a North Dakota silty-clay loam at pH 6.1 kept at 8 C and 45% field capacity moisture and for only 218 d in the same soil when temperature was increased to 16 C and moisture was kept at 90% field capacity (Lym and Swenson 1991). At temperatures below 10 C, the authors stated that sulfometuron degradation by hydrolysis would have a half-life of several months or more.…”

“…Given these soil and environmental conditions, sulfometuron degradation rates would be relatively slow in southern Idaho. Furthermore, because sulfometuron solubility and mobility in high pH soils is greater than in acidic soils (Lym and Swenson 1991), crops grown under irrigation could be subjected to readily available, residual sulfometuron. Hence, sensitive crops could be negatively impacted by ultralow soil residual sulfometuron concentrations for more than one growing season after off-target movement into agricultural fields.…”