A. Martin Petrovic

The influence of a peat amendment and turf density on downward migration of metalaxyl fungicide in creeping bentgrass sand lysimeters

Downward migration of the fungicide, metalaxyl (N-(2,6-dimethylphenyl)-N-(methoxyacetyl)-alanine methyl ester) in irrigated creeping bentgrass (Agrostic palustris Huds) sand lysimeters was studied as a function of two factors: (1) amending sand with peat and (2) density of the bentgrass turf. Based on the determination of metalaxyl in leachates collected at specific intervals following fungicide application, the presence of peat in the sand delayed the downward migration of the fungicide. The percentages of total applied metalaxyl found in the collected leachates generally decreased as turf density and surface organic matter increased. Literature on the subject of the downward migration of metalaxyl in soils is reviewed.

Downward migration of metalaxyl fungicide in creeping bentgrass sand lysimeters as affected by organic waste, peat and zeolite amendments

Metalaxyl is a fungicide used for control of Pythium spp. diseases in turfgrass. The downward migration of metalaxyl was studied in irrigated lysimeters containing a fine sandy loam soil alone or sand amended with composted brewery waste, composted sewage sludge, peat or zeolite by analysis of the fungicide in leachates collected up to 65 days post application. The Arkport sandy loam soil and sand containing peat, brewery waste or sewage sludge amendments showed somewhat similar patterns of metalaxyl in collected leachates increasing from not detectable initially to peak concentrations between 14 and 21 days after first irrigation and decreasing thereafter. The peak concentrations were in the order: brewery waste > peat > sludge > Arkport sandy loam. In the lysimeter treatments containing sand amended with zeolite, the downward migration of the fungicide with time after application generally increased with the highest attained concentration in the leachate inversely proportional to the total amount of zeolite in the respective lysimeter sand profile. Only small percentages (ranging from 0.21 to 1.22) of the total applied fungicide were accounted for in the leachates. The literature is reviewed and the possible mechanisms of fungicide losses are discussed.

Conversion of triadimefon fungicide to triadimenol during leaching through turfgrass soils

The leaching characteristics of the fungicide, triadimefon were studied in a silt loam and a fine sandy loam soil and an acid sand each prepared in plots as lysimeters and seeded with Penncross creeping bentgrass. The effect of sampling interval after last fungicide application and volume of irrigation water on pesticide leaching were studied. In both soils and sand, triadimefon was converted to triadimenol, the latter metabolite being present in the leachate of each growth medium. The concentration of triadimenol in the leachates greatly exceeded that of triadimefon and triadimenol and was much higher in the leachates of the sand than in those of the soils. Factors affecting the movement of pesticides in soils are discussed.

Effect of maturing turfgrass soils on the leaching of the herbicide mecoprop

Abstract Leaching of the herbicide mecoprop, [2-(4-chloro-2-methyl-phenoxy)propionic acid] (MCPP), was studied on three types of turfgrass soils; silt loam, fine sandy loam and acid sand, to assess the potential for ground water contamination. Each soil was prepared in plots as free draining lysimeters and seeded with Penncross creeping grass to simulate golf course fairways. The downward migration of MCPP was determined from collected leachate water and residue analysis were done by high performance liquid chromatography. The extent of pesticide leaching was determined to be a function of interval after herbicide application, amount of irrigation water and maturity of the turfgrass stand. The irrigation and water collection patterns do not explain most of the differences in the leaching profiles, in particular of the sand plots. The concentration of mecoprop in the sand leachates was high compared to the finer textured soils but decreased substantially with increasing time after herbicide application in all three soils as well as with maturity of the grass and with more biomass from first to third year application. Where groundwater monitoring is being done, MCPP is a likely candidate for residue analysis if the site has very sandy soils.

Pesticide fate in sodded kentucky bluegrass lawns in response to irrigation

Abstract Fertilizers and pesticides applied to home lawns can contaminate surface and groundwater making them unfit for aquatic organisms and human consumption. Application of fertilizers and pesticides can improve the aesthetics of a home lawn, improve turfgrass shoot and root density, water use, organic matter accumulation, and other factors known to be influential in urban hydrology. A field study determined the impact of applying home landscape pesticides with or without supplemental irrigation of leaching into groundwater or runoff to surface water. Free-draining lysimeters having a sandy loam soil (coarse-loamy, mixed, active, mesic Lamellic Hapludalf) were used to monitor total volume and nutrients and pesticides losses. Samples from natural precipitation events were analysed for pendimethalin [N-(1-ethylpropyl)-3,4-dimethyl-2, 6-dinitrobenzenamine] applied in spring, mecoprop [2-(4-Chloro-2-methylphenoxy) propionic acid]+2, 4-D (2,4-dichlorophenoxyacetic acid) applied both in late spring and early fall, and bifenthrin [(2-methyl-1,1-biphenyl-3-y1)-methyl-3-(2-chloro-3,3,3-trifluoro-1-propenyl)-2,2-dimethyl cyclopropanecarboxylate] applied in late summer. Pesticide concentrations fluctuated over time, but no differences in concentrations were observed from irrigated or non-irrigated turfgrass for any pesticide. Mecoprop and 2,4-D were the most mobile and values found in runoff during establishment were above maximum contaminant levels (MCL) for U.S. standards. Surface runoff of lawn pesticides were observed at concentrations several magnitudes higher than leachate. The total extent of pesticide runoff was 0.71%, 1.3%, 6.0%, and 0.003% of the amount applied for 2,4-D, mecoprop, pendimethalin and bifenthrin, respectively. With the exception of one sampling period, pendimethalin concentrations in runoff and leachate were low; however, when applied during a period of minimal turf growth and high precipitation, pendimethalin could contribute significantly to surface water pollution.

Soil Phosphorus Levels and Stratification as Affected by Fertilizer and Compost Applications

Little information exists that describes how soil P levels and vertical distribution throughout the soil profile are influenced by fertilization practices and the addition of composted manures. Two field studies were designed to provide more information on how adding P fertilizer or compost influences the concentration and distribution of P in turfgrass soils. Application of P fertilizer at rates of 19, 38, or 72 kg P 2 O 5 per ha/year over a period of 4 or 5 years increased soil P in the upper 0 to 5 cm of soil by a factor of 2.7 to 3.3. Applying P at a rate of 10 kg P 2 O 5 per ha did not increase soil P in the upper 0 to 5 cm of soil. With one exception, soil P levels at depths of 5 to 10 or 10 to 15 cm were not increased by fertilizer applications over a period of 4 or 5 years. In contrast, adding composted poultry or dairy manures to plots at rates of 12 to 24 mm/year resulted in 8 to 333-fold increases in soil P in the upper 5 cm of soil. Soil P levels also increased substantially in deeper layers as a result of poultry compost application, but not for dairy. These findings indicate that common fertilization practices have a much smaller influence on soil P levels compared to composted manures. The benefits of using composted manures must be weighed against the potentially negative environmental impacts that could result from a large increase in soil P layer where runoff occurs.

Triadimenol in turfgrass lysimeter leachates after fall application of triadimefon and overwintering

Abstract An earlier study showed that fall application of the fungicide, triadimefon to sandy turfgrass lysimeter plots resulted in rapid appearance of the metabolite, triadimenol in collected leachates but only occasional presence of the parent fungicide. In the present study, it was shown that, if after such fall applications, leachates are collected and analyzed through the following winter and spring, residues of the metabolite, triadimenol, are detectable as late as early June. Factors influencing these results are discussed.

Leaching of mecoprop herbicide through turfgrass soils

Abstract The downward movement of the herbicide, mecoprop [2-(4-chloro-2-methyl-phenoxy) propanoic acid], was studied in a silt loam and a fine sandy loam soil and an acid sand, each prepared in plots as lysimeters and seeded with Penncross creeping bentgrass. The extent of pesticide leaching was determined as a function of interval after last herbicide application and volume of irrigation water. Mecoprop moved downward in small but detectable concentrations in both soils but its rate of leaching was high in the sand. The concentration of mecoprop in the leachates decreased progressively with increasing time after herbicide application in both soils and the sand. A method of analysis was developed based on electron capture gas chromatographic determination of a ring nitrated and methylated mecoprop derivative. Factors affecting the downward movement of herbicides of similar structure are discussed.

Downward migration of trichlorfon insecticide in turfgrass soils

Abstract The downward migration of the insecticide, trichlorfon (o,o-dimethyl-2,2,2-trichloro-l-hydroxyethylphosphonate) was studied in a fine sandy loam, a silt loam and a sand each prepared in lysimeter plots and seeded with creeping bentgrass. The extent of insecticide leaching was determined as a function of interval after trichlorfon application under two irrigation regimes simulating above or below average precipitation. Trichlorfon moved downward quite rapidly with traces still detectable in leachates 23 days following application. The percentages of total applied insecticide recovered in the leachates were in the range of 1 and 4 percent at the lower and higher rates of irrigation, respectively. Factors affecting the various modes of dissipation of trichlorfon are discussed.

Migration of isazofos nematocide in irrigated turfgrass soils

Abstract The magnitude of migration of the nematocide, isazofos (O-[5-chloro-1-(1-methyl-ethyl)-1H-1,2,4-triazol-3-yl]-O,O-diethyl phosphorothioate) was investigated in a silt loam and a fine sandy loam soil and an acid sand, each prepared in plots as lysimeters and seeded with creeping bentgrass. The amount of pesticide leaching was determined as a function of time after isazofos application. The magnitude of downward migration of isazofos was sand > silt loam > fine sandy loam.