Impacts of zone tillage and red clover on corn performance and soil physical quality

Despite extensive research, reduced corn (Zea mays L.) performance is still encountered using conservation tillage on fine-textured soils in cool humid temperate climates. These problems are intensified when corn is planted into residue from a previous crop such as winter wheat (Triticum aestivum L.). The objective of this 4-yr study was to determine the influence of fall zone tillage (ZT), no tillage (NT), and conventional moldboard plow tillage (CT) (fall plowing) on corn performance and soil physical quality under a winter wheats-corn-soybean (Glycine max L. Merr.) rotation with and without red clover (Trifolium pratense L.) (RC) underseeded in the wheat phase of the rotation. A randomized complete block design (3 x 2 factorial, 4 replicates) was established on three adjacent fields in the fall of 1996 on a Brookston clay loam soil (fine loamy, mixed, mesic, Typic Argiaquoll) at Woodslee, ON Canada, and measurements were collected during 1997 to 2000. Over both wet and dry growing seasons from 1998-2000, zone tillage following underseeded RC produced average corn grain yields (7.23 Mg [ha.sup.-1]) that were within 1% of those obtained using conventional tillage (7.33 Mg [ha.sup.-1]), and 36% higher than those obtained using no tillage and RC (5.33 Mg [ha.sup.-1]). Zone tillage also improved soil quality as evidenced by generally lower soil strength than no tillage, and near--surface soil physical quality parameters that were equivalent to, or more favorable than, those of the other treatments. It was concluded that corn production using zone tillage and RC underseeding is a viable option in Brookston clay loam soil, as it retains much of the soil quality benefit of conventional tillage but still achieves most of the yield benefit of conventional moldboard plow tillage.