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ARS Home » Research » Publications at this Location » Publication #93041
Title: ASSESSING CHEMICAL TRANSPORT USING SOIL SAMPLES VERSUS PERCOLATE SAMPLES

Author
item Malone, Robert - Rob
item Shipitalo, Martin
item Owens, Lloyd
item Nelsen, Terry

Submitted to: Agronomy Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 7/1/1998
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: Soil samples are often used to assess chemical movement into soils. In natural soils, however, preferential flow often occurs and soil samples may be inadequate for assessing chemical transport. We applied weakly and strongly sorbed tracers (atrazine, alachlor, and strontium) to 30 by 30 by 30 cm undisturbed blocks of macroporous no-till soil at 3 initial water contents (dry, intermediate, and wet) then subjected the blocks to 30 mm o simulated rainfall. Percolate samples were collected throughout the rainfall and analyzed for the chemicals. After percolation had ceased, the soil blocks were sliced into eight 3.75 cm thick horizontal layers and analyzed for chemical content. The chemical distributions observed in the soil did not reflect the degree of chemical transport observed with the percolate samples. Therefore, when preferential flow occurs analysis of soil samples alone may lead to erroneous conclusions regarding chemical transport.