Physical Sciences and Mathematics Commons^™

Movement Of Bacteria Through Macropores To Ground Water, M. Scott Smith, Grant W. Thomas, Robert E. White

KWRRI Research Reports

Effects of soil type, flow rate, antecedent soil moisture and other factors on transport of E. coli through soils was measured on disturbed and intact columns 20 cm in diameter by 25 to 30 cm in depth. Added E. coli were distinguished from indigenous microbes using an antibiotic resistance marker. Transport of Cl^- and ³H₂O was also measured. Up to 96 percent of the bacteria irrigated onto the surface of intact columns were recovered in the effluent. Soil structure appeared to be related to the extent of transport. Columns prepared from mixed, repacked soil were much …

The Relation Between Soil Characteristics, Water Movement And Nitrate Contamination Of Ground Water, Grant W. Thomas, Matthew Mcmahon

KWRRI Research Reports

Soils from several areas in Kentucky were placed in columns and leached with Ca(NO₃)₂. Subsoils high in iron oxide were found to retard the leaching of nitrate very significantly. In other soils, the nitrate moved through as fast as or slightly faster than the water.

Field application of nitrogen to corn was most efficient when done in the spring or summer near the time that the corn takes it up. The one exception to this was a red soil, where fall application of nitrogen resulted in little loss due to the retarding effect mentioned in the …