Herbicide Residue Distributions in Relation to Soil Morphology in Two California Vertisols

Graham, Robert C.; Ulery, April; Neal, Rosemary H.; Teso, R.R.

doi:10.1097/00010694-199202000-00005

Cited by 23 publications

(8 citation statements)

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“…Graham et al (1992) reported that in cultivated vertisols in California (USA), herbicides were only found deep below the root zone in samples taken from the cracks' walls and not within the matrix, suggesting rapid transport of herbicides through the cracks, either as solutes or on colloids. Transport of pesticides in preferential-flow paths absorbed on colloids was also suggested for cotton fields on vertisols in Australia (Weaver et al, 2012).…”

Section: Preferential Transport In Vertisolsmentioning

confidence: 99%

Soil–aquifer phenomena affecting groundwater under vertisols: a review

Kurtzman

Baram

Dahan

2016

Hydrol. Earth Syst. Sci.

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Abstract. Vertisols are cracking clayey soils that (i) usually form in alluvial lowlands where, normally, groundwater pools into aquifers; (ii) have different types of voids (due to cracking), which make flow and transport of water, solutes and gas complex; and (iii) are regarded as fertile soils in many areas. The combination of these characteristics results in the unique soil-aquifer phenomena that are highlighted and summarized in this review. The review is divided into the following four sections: (1) soil cracks as preferential pathways for water and contaminants: in this section lysimeter-to basin-scale observations that show the significance of cracks as preferential-flow paths in vertisols, which bypass matrix blocks in the unsaturated zone, are summarized. Relatively fresh-water recharge and groundwater contamination from these fluxes and their modeling are reviewed; (2) soil cracks as deep evaporators and unsaturated-zone salinity: deep sediment samples under uncultivated vertisols in semiarid regions reveal a dry (immobile), saline matrix, partly due to enhanced evaporation through soil cracks. Observations of this phenomenon are compiled in this section and the mechanism of evapoconcentration due to air flow in the cracks is discussed; (3) impact of cultivation on flushing of the unsaturated zone and aquifer salinization: the third section examines studies reporting that land-use change of vertisols from native land to cropland promotes greater fluxes through the saline unsaturated-zone matrix, eventually flushing salts to the aquifer. Different degrees of salt flushing are assessed as well as aquifer salinization on different scales, and a comparison is made with aquifers under other soils; (4) relatively little nitrate contamination in aquifers under vertisols: in this section we turn the light on observations showing that aquifers under cultivated vertisols are somewhat resistant to groundwater contamination by nitrate (the major agriculturally related groundwater problem). Denitrification is probably the main mechanism supporting this resistance, whereas a certain degree of anion-exchange capacity may have a retarding effect as well.

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Section: Preferential Transport In Vertisolsmentioning

confidence: 99%

Soil–aquifer phenomena affecting groundwater under vertisols: a review

Kurtzman

Baram

Dahan

2016

Hydrol. Earth Syst. Sci.

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“…More recently, Graham et al (1992) have detected trifluralin residues in crack walls and directly below open cracks to a depth of 125 cm in the cultivated soil matrix. No residues were detected in the soil matrix between the open cracks, suggesting that the herbicide had moved preferentially via cracks.…”

Section: B Leachingmentioning

confidence: 99%

Environmental Fate of Trifluralin

Grover

Wolt²,

Cessna

et al. 1997

Reviews of Environmental Contamination and Toxicology

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“…Macropores such as earthworm burrows, root channels or cracks provide potential pathways for preferential flow. Graham et al 8 reported in a field study that herbicide residues (atrazine, at levels of 2 to 3750 µg litre −1 ) in a cultivated California Vertisol were detected not only at the surface, but in crack walls and directly below open cracks to a depth of 125 cm, but no residues were detected within the soil matrix between open cracks. This suggested herbicides moved preferentially via the cracks.…”

Section: Introductionmentioning

confidence: 99%