MACROPOROUS INFILTRATION AND REDISTRIBUTION AS AFFECTED BY EARTHWORMS, TILLAGE, AND RESIDUE

The objectives of this study were to determine if burrows produced by two species of earthworms (Aporrectodea tuberculata and Lumbricus rubellus) found in continuous corn (Zea mays L. ) in Minnesota altered the infiltration rate and depth distribution of surface applied water. Each species was introduced (212 m** minus **2) to in situ cylinders in plots initially void of worms that had been subjected to tillage with and without residue or no-till with and without residue for 5 yr. Burrows produced by both species of worms during a 46-d period increased average infiltration rates of 30 mm of water relative to controls after 46 d. Surface residues more than doubled the number of burrows open to the surface relative to incorporated residues. Pore continuity and survival potential for worms in the no-till-residue treatment suggest that this treatment might increase populations of worms in cropland while altering the hydraulic status and erosion susceptibility of soils in the north central USA.