Note to readers, attached is the complete final report for FNE97-170
Mr. Groff has been interested in narrow (15-inch) row planting of corn for some time. In a previous SARE project (FNE96-128) he examined the effects of narrow planting on grain yield, profitability, weed suppression, and the amount of residue left after harvest. He continued his investigations of this technique with the present study, this time examining effects on silage yields as well as grain yields, and erosion control, as indicated by the extent of root growth in the top few inches of soil.
Mr. Groff no-till planted corn into soya stubble. Half the experimental area was planted to 30-inch rows. The other half was planted to 15-inch rows by using the same planter, but doubling back to make a second pass.
Silage yield: The 15-inch plantings produced on average about 12% more silage than did the 30-inch plantings– 21.9 tons per acre, compared to 19.5 tons (six replications; significant at the 0.14 confidence level). Planting density was approximately 27 000 plants per acre.
Grain yield: The 30-inch plantings yielded an estimated 132.4 bushels/acre. The 15-inch plantings yielded approximately 148.6 bushels/acre, representing again, as with the silage, an improvement of about 12%. Here however the results may have been affected somewhat by the planting density, which was higher in the 15-inch rows (29 300 plants/acre) than in the 30-inch rows (26 300 plants/acre).
Root mass: This was not shown to differ significantly between the two treatments.
Mr. Groff figures that planting in narrow rows increased his per acre profit on silage by $57 over and above what he made planting with 30-inch spacing. He figures his profit on grain increased by $30/acre. He recommends narrow row planting of corn as a profitable practice. Last year he demonstrated that it helps to suppress weeds, too, but whether and how much it mitigates soil erosion remains an open question.