Developmental and Growth Effects of Crop Residues on Corn
1990
Fortin, M. -C. | Pierce, F. J.
Residue-related low soil temperatures have been shown to delay corn (Zea mays L.) emergence and silking dates, but it is unclear how residues affect general crop growth during this period. This study was conducted to determine how crop-residue effect on corn development during the vegetative stage affects the measurements of various growth characteristics. The effects of small grain residue cover applied around 50% emergence on corn development (time to reach specific stages), growth (aboveground phytomass, height, N uptake) and soil temperatures were investigated on a Conover loam (mixed, mesic, Udollic Ochraqualf) under irrigated no-tillage conditions. In 1987 and 1988, straw mulch significantly delayed development when compared to a bare soil control, but no consistent difference was found in aboveground phytomass when comparisons were done at similar vegetative stages. Comparisons on a calendar day basis showed significantly lower values for the residue treatment. The latter analysis confounded developmental-delay effects with actual growth. Similar observations were made for height and N uptake. Consequently, an understanding of plant performance in tillage studies, involving significant developmental differences between treatments, requires that the response curve of a growth characteristic over time be coupled with data on development. Contribution from Michigan Agric. Exp. Stn. Research supported in part by Agriculture Canada, Harrow, Ontario.
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