Pesticide Dissipation under Golf Course Fairway Conditions

Abstract

The degradation and vertical movement of pendimethalin, chlorpyrifos, isazofos, and metalaxyl were monitored in Kentucky bluegrass (Poapratensis L.) turf managed as a golf course fairway. Intact turf‐soil cores from Mead, NE, on a Sharpsburg soil (fine montmorillonitic, mesic Typic Argiudoll) and Gilbert, IA, on a Nicollet loam (fine‐loamy, mixed, mesic Aqnic Hapludoll) planted to Kentucky bluegrass were periodically removed to 60‐cm depth through 113 d after pesticide application. Cores were sectioned into verdure, thatch, and multiple soil depths. While verdure contained high pesticide concentrations after application, precipitation, and clipping, and degradation reduced the amount in plant tissue with time. Thatch was highly retentive of the pesticides, generally containing the most residue throughout the monitoring period. Pesticide residues tended to be lower in soil at the Iowa site where more thatch was present. Little chlorpyrifos or pendimethalin moved through the thatch to the underlying soil. Isazofos was more mobile and metalaxyl moved through the entire soil column. Soil contained an average of 58% less pesticide than thatch over all sampling times, and concentrations in soil were highest at the 0‐ to 5‐ and 5‐ to 10‐cm depths. Average time for 50% dissipation in the turf‐soil profile (DT50) was 16, 12, 10, and 7 d for metalaxyl, pendimethalin, chlorpyrifos, and isazofos, respectively. The pesticides appeared to degrade more rapidly in the turfgrass environment than typically reported for other agronomic cropping systems. Variability in pesticide residue concentrations for each soil depth among the turf‐soil cores indicated non‐uniform dissipation in the field.

Persistence, Mobility, and Bioavailability of Pendimethalin and Trifluralin in Soil

“…Field studies of pendimethalin have indicated very little leaching through soil columns (21). This lack of movement, coupled with previous reports of higher dissipation rates of pendimethalin on golf course thatch (15), may explain why detectable water contamination was not present on the golf course. However, if contamination of the water did occur, pendimethalin is likely to partition quickly into the sediment, which was not tested.…”

“…For instance, pendimethalin has been reported to have dissipation half-lives of 37 days in onion fields (13), 47 days in agronomic soil (14), and 12 days in thatch on a golf course (15). Other laboratory studies have reported pendimethalin half-lives as long as 98 days at 30°C and 407 days at 10°C (16).…”

Spatial and Temporal Distribution of Fungicides Applied to Creeping Bentgrass

“…The increased sorption correlates to a lower potential for fungicides in turf to migrate off site. Horst et al (1996) evaluated four pesticides for their mobility in a Kentucky bluegrass fairway.…”

“…The third factor in determining fungicide performance is persistence in the environment (Latin, 2011 Horst et al (1996) reported the half-lives of metalaxyl, pendimethalin, chlorpyrifos, and isazofos in a Kentucky bluegrass fairway to be 16, 12, 10, and 7 days, respectively. These values are lower than half-lives of these pesticides in agricultural soils.…”

“…Thom et al (1997) examined the effects of pretreatment and organic amendment on the degradation of difenoconazole. Horst et al (1996) monitored the vertical movement and dissipation of pendimethalin, chlorpyrifos, isazofos, and metalaxyl. Sorption studies were conducted for the fungicides triadimefon, vinclozolin, and chloroneb in thatch and soil (Dell et al, 1994).…”