Assessment of Management Practices for Reducing Pesticide Runoff from Sloping Cropland in Illinois

Abstract

The influence of tillage system and contouring practice on runoff of soil-applied alachlor ]2-chloro-2',6'-diethyl-N-(methoxymethyl) acetanilide], carbofuran (2,3-dihydro-2,2-dimethyl-7-benzofuranyl methylcarbamate), and terbufos (S-](tert-butylthio)methyl] O,O-diethyl phosphorodithioate) from small plots (30 2) w ere studied u sing a rainfall simulator. Plots were planted in corn (Zea mays L.) in 1983, soybean ]Glycine max (L.) Merr.] in 1984, and corn in 1985. Runoff was measured during a 60-min event with a rainfall intensity of 63 mm/h. During 1984, moldboard-plowed and no-till systems were studied with rows oriented on the contour or up-and-down slope (7-11% slope). Compared to moldboard plow, up-and-down slope no-till and contouring significantly reduced runoff of carbofuran and alachlor. Percentage of applied carbofuran lost in runoff and sediment ranged from 1% (contoured moldboard) to 11% (up-and-down slope moldboard). Percentage of applied alachlor lost ranged from 1% (contoured no-till) to 2% (contoured moldboard). During 1985, the effects of row orientation were evaluated on moldboard-plow, chisel-plow, ridge-till, strip-till, and no-till systems. Under up-anddown slope conditions, runoff of alachlor and terbufos plus two metabolites (terbufos sulfoxide and terbufos sulfone) was significantly reduced by strip-till (<1% loss) compared to moldboard-plow (6% loss). Larger losses of alachlor (2% of applied) from up-and-down slope no-till than from the other conservation tillage systems (1% or less) was attributed to high concentrations in runoff associated with extensive washoff of the herbicide from soybean crop residues. With contouring, ridge tillage also was effective in reducing pesticide runoff (<1% of applied pesticide), and strip-till held losses to 0.1%. Alachlor and carboforan were translocated from plots largely in moving water, but terbufos and metabolites were recovered mainly in eroded sediment. Although, no conservation tillage system completely eliminated pesticide runoff, losses were most effectively minimized by contoured strip-till and no-till, which controlled both water and sediment movement.

Herbicide Banding and Tillage System Interactions on Runoff Losses of Alachlor and Cyanazine

“…The percent of total alachlor lost in the water phase was not different among tillage ( P = 0.970) or herbicide application method ( P = 0.600) and averaged 88% for both years. Other studies have shown similar percentages of total alachlor loss in the water phase (Felsot et al, 1990; Khakural et al, 1994). Although the concentration of alachlor was much greater per unit mass of sediment than per unit mass of water, the total mass of sediment lost in runoff was small compared with the mass of water.…”

“…These values are similar to those obtained in other runoff studies. For example, Felsot et al (1990) reported K d values for alachlor and eroded sediment ranging from 5.6 to 8.4 L kg −1 and Baker et al (1978) reported values for alachlor as high as 10.8 L kg −1 For cyanazine and eroded sediments, a K d value of 2.8 was reported (Hall et al, 1984).…”

“…Some studies show greater concentrations and greater losses of herbicides in runoff from conservation tillage systems than from conventional tillage approaches due to greater runoff volumes, greater herbicide concentrations, or both (Baker et al, 1978; Isensee and Sadeghi, 1993; Gaynor et al, 1995). In other studies, herbicide losses are reduced for conservation tillage practices due to a reduced runoff volume and sediment loss (Felsot et al, 1990; Hall et al, 1991).…”

Tillage management effects on pesticide fate in soils. A review

“…Several studies indicated that conservation tillage was inefficient in controlling runoff when heavy rainfall occurs quickly after pesticide application (Rector et al, 2003;Shipitalo and Owens, 2003;Shipitalo and Owens, 2006). Moreover, most pesticide loss by Felsot et al, 1990) Alachlor 3.36 --941, 1158, 824, 926, 1029, 860 5, 6, 7, 18, -, 1 1, 4, 7, 18, 18 -50, 35-38 31-56, 35-48 16-24, 34-47 2.2-9.4, 2.1-4.7 1.7-8.1, 1.9-2.5 0.5-1.6, 1.7-3.0 (Myers et al, 1995) Atrazine 0.9 0.9 Inc. (Malone et al, 1996) 392 L. Alletto et al (Kenimer et al, 1987) 1 Codes of tillage practices are reported in Table I. Loc: seed row localisation of the pesticide treatment.…”

“…Pesticide incorporation into soil through superficial tillage was found to significantly reduce losses by runoff (Franti et al, 1998;Olson et al, 1998;Rector et al, 2003) but this technique is not suitable for no-tillage systems and may lead to an increase in losses by leaching. Finally, whatever the tillage system, soil tillage along isotopographic lines rather than up-and-down slope was efficient in reducing transfers by runoff (Felsot et al, 1990).…”