Contaminant Transport in Agroecosystems through Retention of Soil Particles on Plant Surfaces
The contamination of plant surfaces with soil particles is a potentially important process in the transport of insoluble contaminants such as radionuclides, heavy metals, and hydrophobic organics in agroecosystems, but few data are available to assess the significance of this mechanism for different crop species. The mass of soil particles retained on the surfaces of corn (Zea mays L.) and sunflower (Helianthus annuus L.) grown under field conditions were measured using the 238Pu content of the plants to indicate retention of soil. The crops demonstrated similar quantities and height distributions of soil retained on leaf and stem surfaces. Mean retention was 0.86 g soil retained on corn vegetation per square meter of land surface and 0.79 g m−2 retained on sunflower. Most of the soil was on the lower 1 m of the vegetation. The height distributions of retained soil can explain the larger concentrations of soil observed in the mechanically harvested grains of short stature crops such as wheat (Triticum aestivum L.) (120 mg soil per kg grain) and soybean [Glycine max (L.) Merr.] (82 mg kg−1) than that observed in taller crops such as corn (2 mg kg−1). The significance of soil retention in determining the accumulation of contaminants in grains is evaluated for several important agricultural crops.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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