Establishing and Maintaining Enhanced Infiltration Through Shallow and Deep Tillage with Soil Amendments.

Establishing and maintaining enhanced infiltration through shallow and deep tillage with soil amendments.

Virginia K. Brown, Richard A. McLaughlin, Barrett L. Kays, and Joshua L. Heitman

Abstract

The process of constructing roads and building usually involves the removal of topsoil, grading, and traffic from heavy machinery and trucks handling construction supplies.  The result is compacted subsoils with low fertility, which hinder vegetation establishment, limit infiltration and are susceptible to erosion.  The goal of this project is to quantify methods for restoring perviousness of surface soils compacted by construction equipment by increasing storm water infiltration and accelerating vegetative growth.  We are evaluating three treatments: a compacted soil, a compacted soil with shallow tillage (15cm), and a compacted soil with deep tillage (30cm) and two rate of liming. The objectives are to measure runoff quantity and quality, infiltration rate, biomass production, and rooting depth for each treatment.  Soil compaction and resistance from penetrometer readings show little difference between the deep and shallow tillage treatments from the surface to 6 inches.  Resistance was high from the surface to a 12 inch depth on the compacted treatment while the deep tillage treatment showed minimal resistance or increase with depth. Preliminary data from rain events indicate that the tillage treatments substantially reduce runoff and have significantly higher infiltration ratres.  Runoff water quantity and quality data will be presented for the first six months of the project.