Narrow-Row Corn Production in the Mid-South.

The objective of this research was to evaluate the effect of row spacing and population on yield. In this study, corn was planted at three locations: Starkville, Stoneville, and Verona, MS. Two row-spacings were evaluated: 19” and 38” and five seed populations: 25k, 35k, 45k, 55k, 65k ac^-1, were evaluated. Two weeks prior to planting, 100 lbs ac^-1 of N, 46 lbs ac^-1 of P, and 60 lbs ac^-1 of K were broadcast. Corn was planted with a 19” row Monosem vacuum planter and 38” John Deere MaxEmerge vacuum planter. At V6, we hand applied a sidedress application of 200 lbs of N, via urea, at the base of the plants along the 30ft long by four row wide plot. Variables measured included plant height, ear height, LAI, SPAD, yield components and stalk diameter. The middle two rows of each four-row plot were harvested at approximately 16% moisture. Across all three locations there was an insignificant 4 bu ac^-1 increase (P = .5728) moving into narrower rows. The highest yielding treatment at the MSU location was 291 bu ac^-1 on the 19” spacing. The highest yielding treatments in this trial and two others similar to it were between 40 to 45K populations suggesting that with the hybrids we have now, at the fertility rates we are using currently, (300 Units N) we gain no economic benefit increasing population beyond this level. A producer could use this planting strategy to effectively use (1) planter for soybean and corn on 19” spacing and cotton on a 38” spacing. We also note that this year was particularly wet and cool and that there may be additional benefits attributable to narrow row production because of enhanced shading, quicker canopy, and cooler soil temperatures in a hot/dry year.