Submitted to: Agronomy Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: July 7, 1995
Publication Date: N/A
Interpretive Summary: Many farmers are including no-till and ridge-till systems in their conservation plans. In conventional tillage systems, tillage operations produce uniform soil conditions throughout the tilled layer. In no-till and ridge-till systems, however, wheel traffic compaction creates dramatically different soil conditions in rows, tracked interrows, and untracked interrows. Because corn root growth is affected by wheel traffic compaction, root distribution in no-till and ridge-till systems is not uniform like it is in tilled systems. Information concerning early season root distribution in no-till and ridge-till systems is needed so that nitrogen fertilizer placement can maximize uptake efficiency and farmers can evaluate the benefits of controlled traffic. The objectives of this study were to examine the effects of tillage systems and wheel traffic patterns on corn yield and root distribution. This study showed that corn root growth was affected more by wheel tracks than by tillage. Roots avoided wheel tracks, but this response was also affected by the wheel traffic pattern in adjacent interrows. Yields of rows with a trafficked interrow on only one side were 7% less than those of rows without trafficked interrows on either side. Fertilization in wheel tracks should be avoided because wheel tracks limit root growth.
Technical Abstract: Controlled wheel traffic is one way to manage compaction in no-till and ridge-till systems. This study was conducted from 1990 to 1992 at Kanawha, IA on a Webster silty clay loam to examine the effect of a wheel traffic pattern on corn root distribution, shoot growth, and yield in no-till, ridge-till, and chisel-plow systems. The wheel traffic pattern was configured so that some rows would have wheel tracks on both sides, on one side, or on neither side. In general, the effect of tillage systems was not significant. Position relative to the traffic pattern, however, had some effect on all measured parameters. Bulk density was greatest in trafficked interrows (1.36 Mg m**-3) and least in untrafficked interrows (1.09 Mg m**-3). Hydraulic conductivity near saturation was less in trafficked interrows (39.4 um s**-1) than in untrafficked interrows (104.7 um s**-1). Root length in trafficked interrows was on average one-third of that of untrafficked interrows. Root length in a particular interrow also was influenced by the traffic pattern in the adjacent interrows. Yields of rows with a trafficked interrow on only one side were 7% less than those of rows without trafficked interrows on either side in two of the three years. The wheel traffic pattern, and not just the presence or absence of wheel traffic, affected corn root growth and yield.