Wheel-traffic effects on corn as influenced by tillage system

Abstract

Surface and subsoil compaction limit crop productivity on many soils of the southeastern Coastal Plain of the United States. Deep tillage, and to a lesser extent, controlled traffic have been utilized to manage soil compaction on these soils, but there is a need to develop tillage systems that integrate conservation tillage practices with deep tillage and controlled traffic. In 1988, a study was initiated with a wide-frame (6.3 m) vehicle to determine the interactive effects of traffic, deep tillage, and surface residues on corn ( Zea mays L.) grown on a Norfolk loamy sand (fine-loamy, siliceous, thermic, Typic Kandiudults). Corn was planted into a winter cover crop of ‘Cahaba White’ vetch ( Vicia sativa L.) Treatments included: traffic (conventional equipment or no traffic); deep tillage (no deep tillage, in-row subsoiling, or complete disruption); surface tillage (no surface tillage or disk and field cultivate). Complete disruption was accomplished by subsoiling at a depth of 43 cm on 25-cm centers. Although tillage × traffic interactions significantly affected soil strength and soil water, the only grain yield response both years was due to a surface tillage × deep tillage interaction. In a drought year (1988), with surface tillage, yields averaged 3.54, 2.75, and 1.41 t ha −1 with complete disruption, in-row subsoiling, and no deep tillage, respectively. Without surface tillage, respective yields averaged 3.77, 3.14, and 1.12 t ha −1. In 1989 when rainfall amount and distribution were excellent, yields with complete disruption, in-row subsoiling, and no deep tillage averaged 7.79 t ha −1, 7.08 t ha −1, and 6.44 t ha −1, respectively, with surface tillage; and 7.40 t ha −1, 6.91 t ha −1, and 4.70 t ha −1 respectively, without surface tillage. Soil strength and soil water measurements confirmed the detrimental effect of traffic after disking and field cultivation; however, soil water measurements and the lack of any yield response to applied traffic suggest that corn compensated for reduced rooting capacity in wheeled interrows by increased rooting in non-wheeled interrows.