- Effect of Winter Rye Cover Crop Planting Date on Weed Control in No-till Corn. W. S. Curran and E. L. Werner, 1997. WSSA Abstracts 37:204.
- Effect of a Rye Cover Crop on Weed Control and Corn Growth and Yield. W. S. Curran, E. L. Werner, and G. W. Roth, 1994. Proc. NEWSS 48:69.
Effect of Winter Rye Cover Crop Planting Date on Weed Control in No-till Corn. W. S. Curran and E. L. Werner, 1997. WSSA Abstracts 37:204.
Winter rye was seeded at 125 kg ha-1 in early September, early October, and early November of 1993, 1994, and 1995. The following May of each year, 1.12 kg ai ha-1 glyphosate plus 0.6 kg ae ha-1 2,4-D butoxyethyl ester was applied prior to no-till corn planting for control of the rye cover crop and emerged weeds. Flumetsulam plus metolachlor was applied preemergence to the corn crop at 0.5X, 0.75X, and 1X rates (X = 2.7 kg ai ha-1). Cover crop biomass, corn population, weed control, weed density, weed biomass, and corn grain yield were evaluated during the growing season. Rye biomass ranged from 338 kg ha-1 in the November seeding to 4330 kg ha-1 in the September seeding date. Corn population was reduced in the September rye planting in 1994 and 1996 and in all three rye planting dates in 1995. Control of common lambsquarters (Chenopodium album L.) and smooth pigweed (Amaranthus hybridus L.) was better in the no-rye treatments compared to September seeded rye in two of three years. The effect of rye residues on Velvetleaf (Abutilon theophrasti Medik) control was inconsistent across years with better velvetleaf control in the no-rye treatments in 1994, improved control in the September rye planting in 1995, and no difference in control due to rye cover in 1996. Giant foxtail (Setaria faberii Herrm.) control was unaffected by rye residues. In general, the performance of reduced herbicide rates was better in the no-rye treatment compared to the rye treatments. Common lambsquarters and smooth pigweed control in the reduced herbicide rate September rye planting was usually 5 to 15% less than for the other treatments. The performance of the full herbicide rate (1X) was equal regardless of rye cover crop. These data suggest that reduced rate preemergence herbicide programs combined with high residue cover crops can provide unacceptable weed control in no-till corn.
Effect of a Rye Cover Crop on Weed Control and Corn Growth and Yield. W. S. Curran, E. L. Werner, and G. W. Roth, 1994. Proc. NEWSS 48:69.
Cover crops are promoted for reducing soil erosion, providing or scavenging nitrogen, and possibly Corn after Cover Crop suppressing weed growth and competition. Cereal rye is a common cover crop that is inexpensive to establish, has good winter hardiness and has been widely accepted by northeastern dairy producers. A winter rye cover crop can be killed with a preplant herbicide prior to no-till corn planting or harvested as a forage which provides additional feed to the livestock producer. The effect that rye stage of growth or forage removal at corn planting time have on weed control and corn establishment and yield are uncertain. The objectives of the following study were to determine the effect of rye kill date and rye forage removal on herbicide performance and corn growth and yield.
The studies were established in 1992 and 1993 at the Russell E. Larson Agricultural Research Center in central PA and the Southeastern Agricultural Research Center near Lancaster, PA. Cereal rye was seeded in early to mid October at 2.2 bu/A and killed the following spring two weeks before corn planting or at corn planting by applying 1.0 lb ai/A glyphosate. Additional treatments included removing the above-ground rye biomass using a forage chopper and plots not seeded to rye. All treatments received the glyphosate burndown treatment. Within the four cover-crop treatments (rye-early, rye-late, ryelage, and no-rye) residual herbicide treatments included 0.5, 0.75, or 1X the recommended rates of atrazine plus dicamba applied preemergence or postemergence. In addition, all plots were treated preemergence with 1.5 lb ai/A metolachlor.
Rye cover crop growth and yields were normal in three locations and below normal in the forth location over the two-year period. Above ground rye biomass at corn planting time ranged from 1300 (rye-early) to 4900 (rye-late) lb/A (dry-wt basis). Corn population was significantly reduced or unaffected by the rye cover crop. Populations were lower in the late kill rye treatments both years at the SE location and in all rye treatments at the SE location in 1993. Early season corn height was shorter in the ryelage treatments in three of four experiments, but varied in height in the other cover treatments. The most consistent weed species included giant foxtail (Setaria faberii Herrm.), common lambsquarters, (Chenopodium album L.), and smooth pigweed (Amaranthus hybridus L.). Weed density varied within cover treatments, but generally was lowest in the no rye treatments. Herbicide rate by cover crop interactions were common, particularly with the preemergence treatments. The lower preemergence rates tended to be less effective in rye residue plots, compared to no rye. The postemergence treatments overall tended to be more consistent and less rate dependent. The untreated checks always had the highest weed populations. The effect of cover on corn yield was variable, but yields tended to be highest in the no-cover plots. Yields were consistently lowest in the untreated herbicide plots.
In summary, a rye cover crop has the potential to impact corn establishment with the late kill rye treatments having the greatest likelihood of reducing corn stand. The impact of a rye cover crop on growth and yield was variable, but harvesting the rye for forage prior to corn planting did not eliminate some negative effects. Weed populations were either similar within the cover crop treatments, or tended to be lower in the absence of a rye cover crop. The reduction in weed control in the rye cover was due to less effective preemergence herbicide activity at the lower rates in the rye.