Preferential Movement of Pesticides and Tracers in Agricultural Soils

Steenhuis, T. S.; Staubitz, W.W.; Andreini, M.; Surface, Jan M.; Richard, Tom L.; Paulsen, Robert; Pickering, N. B.; Hagerman, James R.; Geohring, Larry D.

doi:10.1061/(asce)0733-9437(1990)116:1(50)

Cited by 78 publications

(40 citation statements)

References 8 publications

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“…In the fall of 1984, each plot had a drainage pipe installed at an average depth of 8Ocm. The pipes run the length of the plot, ending in a manhole (Steenhuis et al, 1990a). The drainage lines are offset from the center of each plot by 3 m to the north, since it was thought that the slope would affect the flow to the drainage lines.…”

Section: Experimental Methodsmentioning

confidence: 99%

A simple mixing layer model predicting solute flow to drainage lines under preferential flow

Shalit

Steenhuis

1996

Journal of Hydrology

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Concern about the environmental effects of agricultural chemicals through preferential flow has risen in recent years. A simple model is presented describing the processes involved in preferential transport of both soil-adsorbed and non-adsorbed solutes. The model assumes that water and solutes are mixed into an upper soil layer. The water and solutes then flow through macropores to the groundwater. Analysis of the solute breakthrough curves in subsurfact drainage effluent makes it possible to calculate the depth of the mixing layer or the adsorption desorption partition coefficient. Data from a drainage experiment with chloride, 7.4-D and atrazine were used to test the model. The study was performed on a no-till and a conventionally tilled plot. The model and experimental results indicate that only a fraction of the field area participates in transport to the macropores. Differences between breakthrough curves from the conventionally tilled and no-till plots are explained well by the mixing of solutes and water in the upper layer. This simple, physically based model can help us to understand and estimate the environmental threats of herbicides shortly after application.

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Section: Experimental Methodsmentioning

confidence: 99%

A simple mixing layer model predicting solute flow to drainage lines under preferential flow

Shalit

Steenhuis

1996

Journal of Hydrology

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“…However, they also produce negative effects, acknowledged by a few researchers, but ignored by most. Earthworm burrows increase bypass flow and rapid movement of surface-applied contaminants to groundwater (Cohen, 1997;Edwards et al, 1989Edwards et al, , 1992Edwards et al, , 1993Ehlers, 1975;Hall et al, 1989Hall et al, , 1991Isensee et al, 1990;Tyler and Thomas, 1977;Shipitalo et al, 1994;Steenhuis et al, 1990;Trojan and Linden, 1992;Zachmann et al, 1987;Zachmann and Linden, 1989). In rainfed agriculture, earthworms help reduce runoff and erosion.…”

Section: Conceptual Contradictions and Dysfunctionsmentioning

confidence: 99%

Reservations Regarding the Soil Quality Concept

Sojka

Upchurch

1999

Soil Science Soc of Amer J

208

121

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We consider the appropriateness of institutionalizing soil quality as a defined parameter in soil science. The soil management research of land grant universities and the Agricultural Research Service (ARS) and the mission and goals of state, federal, and private conservation agencies stand to be significantly affected. We feel that a non-advocalive examination of this concept could provide a positive contribution.

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“…Soil cracks appear to be having an effect in initially dry soils, particularly in degraded profiles, while stable macropores in rehabilitated profiles are probably the most important mechanism. Measurement of by-pass flow in the field is difficult, requiring a large array of sensors (Williams et al 2000), tracers (Steenhuis et al 1990), and large lysimeter trays inserted in situ. Further work along these lines is needed.…”

Section: General Discussion and Conclusionmentioning

confidence: 99%

Rapid internal drainage rates in Ferrosols

Bell¹,

Bridge

Harch³

et al. 2005

Soil Res.

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Abstract. Adoption of conservation tillage practices on Red Ferrosol soils in the inland Burnett area of south-east Queensland has been shown to reduce runoff and subsequent soil erosion. However, improved infiltration resulting from these measures has not improved crop performance and there are suggestions of increased loss of soil water via deep drainage. This paper reports data monitoring soil water under real and artificial rainfall events in commercial fields and long-term tillage experiments, and uses the data to explore the rate and mechanisms of deep drainage in this soil type.Soils were characterised by large drainable porosities (≥0.10 m 3 /m 3 ) in all parts of the profile to depths of 1.50 m, with drainable porosity similar to available water content (AWC) at 0.25 and 0.75 m, but >60% higher than AWC at 1.50 m. Hydraulic conductivity immediately below the tilled layer in both continuously cropped soils and those after a ley pasture phase was shown to decline with increasing soil moisture content, although the rate of decline was much greater in continuously cropped soil. At moisture contents approaching the drained upper limit (pore water pressure = −100 cm H 2 O), estimates of saturated hydraulic conductivity after a ley pasture were 3-5 times greater than in continuously cropped soil, suggesting much greater rates of deep drainage in the former when soils are moist.Hydraulic tensiometers and fringe capacitance sensors monitored during real and artificial rainfall events showed evidence of soils approaching saturation in the surface layers (top 0.30-0.40 m), but there was no evidence of soil moistures exceeding the drained upper limit (i.e. pore water pressures ≤ −100 cm H 2 O) in deeper layers. Recovery of applied soil water within the top 1.00-1.20 m of the profile during or immediately after rainfall events declined as the starting profile moisture content increased. These effects were consistent with very rapid rates of internal drainage. Sensors deeper in the profile were unable to detect this drainage due to either non-uniformity of conducting macropores (i.e. bypass flow) or unsaturated conductivities in deeper layers that far exceed the saturated hydraulic conductivity of the infiltration throttle at the bottom of the cultivated layer. Large increases in unsaturated hydraulic conductivities are likely with only small increases in water content above the drained upper limit. Further studies with drainage lysimeters and large banks of hydraulic tensiometers are planned to quantify drainage risk in these soil types.

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Preferential Movement of Pesticides and Tracers in Agricultural Soils

Cited by 78 publications

References 8 publications

A simple mixing layer model predicting solute flow to drainage lines under preferential flow

A simple mixing layer model predicting solute flow to drainage lines under preferential flow

Reservations Regarding the Soil Quality Concept

Rapid internal drainage rates in Ferrosols

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