Author
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Teasdale, John |
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Submitted to: Weed Science
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 3/12/1998 Publication Date: N/A Citation: N/A Interpretive Summary: There is much interest recently in growing corn at higher populations and narrower rows. There also is interest in using high populations and narrow rows to suppress weed populations in corn. This research demonstrated that corn grain yield was highest at 1.5 times the normal population when soil moisture was good but that higher populations reduced yield when soil moisture was low. Seed production by an important weed in corn, velvetleaf, was reduced 69 to 94% by corn at a population 1.5 times normal. In contrast, growing corn in a row spacing half the normal spacing had no effect on corn or velvetleaf yield. Results suggest that higher corn populations could increase yield and improve weed suppression. The most important contribution of higher corn populations to weed management was the substantial reduction in weed seed production and the resulting reduction in soil weed seed populations that could infest future crops. This research will be used by the research community for fundamental studies. Technical Abstract: Research was conducted to determine the optimum population and row spacing for corn production and for suppressing velvetleaf growth and seed production. Corn was grown in a factorial arrangement of three populations targeted at 64,000 (1.0X), 96,000 (1.5X), or 128,000 (2.0X) plants ha-1 and two row spacings of 38 or 76 cm. Influences on corn yield were determined in weed-free plots and influences on velvetleaf were determined in plots with target velvetleaf plants established at 1.5 m intervals between corn rows. Four velvetleaf plantings were made at weekly intervals beginning at corn planting. Corn row spacing had little influence on corn or velvetleaf yield. Corn yield exhibited a parabolic response to population with an optimum of approximately 90,000 plants ha-1 in one year, showed no response to population in another year, and linearly declined with increasing population in a droughty year. Velvetleaf produced no seed regardless of corn population when emergence was later than the 5-leaf stage of corn. Velvetleaf seed production was reduced 69 to 94% by the 1.5X population and 99% by the 2.0X population compared to the standard 1.0X population. Reduced velvetleaf seed production was correlated with lower positioning of plants in the corn canopy and reduced light availability. Results suggest that higher corn populations could aid integrated weed management strategies by reducing seed production and limiting the buildup of weed populations. |
