Location: Crop Protection and Management Research
Title: Effects of crop density on yield and weed populations in Georgia grown corn Authors
Submitted to: Proceedings of Southern Weed Science Society
Publication Type: Abstract Only
Publication Acceptance Date: February 1, 2011
Publication Date: June 1, 2011
Citation: Scully, B.T., Webster, T.M. 2011. Effects of crop density on yield and weed populations in Georgia grown corn. Proceedings of Southern Weed Science Society. 64:270. Technical Abstract: Over the last twenty years much of the US corn production has primarily been grown on 92 cm and 76 cm row spacing. With the increased use of hybrids with upright leaf architecture, herbicide and insect resistance there is sufficient flexibility in the cropping system to warrant examination of “Narrow-Row” production. The purpose of this research was to determine if narrow row corn production conveyed any yield advantage on the U.S. southeastern Coastal Plain, and to asses any changes in weed cover under different plant configurations. Two corn hybrids including Dekalb ‘DK69-43’ and Pioneer ‘P31G97’ were grown for two years (2009 and 2010) on the Coastal Plain of southern Georgia. Experiments were designed as an augmented randomized complete block with a treatment structure that used three population densities (47,880, 71,750, and 143,500 plants/ha) and two contrasting configurations within each population density, including: 1) 92 X 23 cm vs 46 X 46 cm; 2) 92 X 15 cm vs 46 X 30 cm; and 3) 92 X 8 cm vs 46 X 15 cm. Averaged over two years, corn yields on the 46 cm narrow row configurations were 5.6%, 14.5% and 17.7% higher than 92 cm standard row spacing across the three planting densities. This yield increase for the Coastal Plain is considerable higher than the 2.0% to 4.0% increases acquired in the Midwest Corn Belt or the 8.0 to 10.0% yield increases obtained in Michigan and Minnesota. Weed ground cover was also influenced by all main effects including corn population density, row spacing, and hybrid. Higher population densities reduced weed cover significantly as did the 46 cm narrow row configuration, which closed canopy sooner than the standard 92 cm row spacing. Between the two hybrids, weed cover was significantly reduced under the canopy of P31G97 as compared to DK69-43.