Effect of conservation tillage systems on corn root growth

The effects of conservation tillage on crop production have been widely investigated, but less information is available on root growth with different tillage systems over a range of soils. In this study, we compared corn (Zea mays L.) root length density and distribution with conventional moldboard plowing (MP) and 3 conservation-tillage treatments: chisel plowing (CH); ridge-tillage (RT); no-tillage (NT); for Griswold and Kewaunee silt loam and Plainfield loamy-sand soils. Root length densities were determined for the row (R), non-wheel track (NWT) and wheel track (WT) positions for two growing seasons (1982 and 1983). Conservation-tillage systems had equal or higher root densities than MP for all positions and depths at all 3 sites. Maximum root densities occurred between 10 and 40 cm for all tillage systems at all locations. In most cases, reduced root growth was associated with wheel traffic positions. Wheel traffic reduced root densities in the surface 10 cm by as much as 52% in MP at the Plainfield site.