Monday, November 13, 2006

Controlled Wheel Compaction Effects on Soil Pore Structure and Corn Yield.

Jonas Zhang1, John Norman*1, Orlando Zuņiga2, and Aicardo Roa1. (1) University of Wisconsin,Madison, Department of Soil Science, 1525 Observatory Drive, Madison, WI 53705-1635, (2) Universidad del Valle, Laboratorio de Fisica Ambiental, A.A. 25 360, Santiago de Cali, Colombia

Compaction-induced soil degradation from large machinery compression is a major concern in any modern agricultural operation. An experiment was set up at Arlington, WI on an undisturbed field, which had not been cultivated for over 15 years.  Treatments of compaction, non-compaction and tillage, no-tillage were compared. The compaction plots were compacted with a loaded John Deere 9400 combine with a Spring-Fall cycle. Besides the compaction equipment, all the necessary traffic including human foot prints were restricted in designated areas. Six rows of corn (RK232) were planted on each plot. Soil property alternations would be indicated by soil bulk density, soil thermal conductivity, hydraulic conductivity, penetrometer resistance and pore size distribution. Following the 2005 Spring compaction with a partially loaded combine and tillage, soil properties and the corn yield did not have significant change. Two subsequent compactions with a loaded combine have increased soil bulk density, thermal conductivity, and penetrometer resistance and reduced macropore percentage down to a depth of twelve inches from the surface.