|GUPTA SATISH C|
|MONCRIEF JOHN F|
Submitted to: Clean Water Clean Environment 21st Century Conference Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 1/5/1995
Publication Date: N/A
Technical Abstract: Laboratory and field studies quantified the effects of tillage and liquid dairy manure on earthworms and macroporous flow in a soil of the upper midwest's karst region. Field measurements showed that manure treatments had significantly higher macroporous flow and macroporosity than the fertilizer treatment although there was no significant differences in numbers of earthworms. In one of the three replications closer to the alfalfa plot and farmer's lawn, Lumbricus terrestris was located in manure treatments. In this replication, chloride appeared much earlier during breakthrough curves for the manure than the fertilizer treatment. Visible surface macropore were also continuous to much deeper depths in soil columns taken from manure than inorganic fertilizer plots. Macroporous flow was higher for the chisel plow compared to no-till treatment although number of earthworms were significantly greater in no-till than in chisel plow plots. These studies showed that burrow morphology was the major determinant in controlling preferential transport by earthworms. A laboratory incubation study was undertaken to quantify the effects of three species of earthworms and two placements of food on burrow morphology and their impact on preferential transport. Preliminary results indicate early appearance of chloride in breakthrough curves with burrows formed by L. rubellus followed by L. terrestris and Apporectodea trapezoides and with soil surface applied residues than residue buried at 10 cm. Work is underway to analyze morphology of burrows formed by these species using Computed Tommography and then relating morphology to preferential transport.