Slowest planting sped of 4 miles per hour produced the significantly best stand placement over 5 miles per hour, which was significantly better than 6 miles per hour, in a replicated trial this summer. However, final yields were about the same for the 5 and 6 miles per hour levels, and lowest for the 4 miles per hour level. It bordered on being significantly lower at the 0.9 level, notes Jeff Phillips, Extension educator in Tippecanoe County, Ind. However, since it wasn't, at that confidence level, the difference in yield could have been due to chance.
Dave Nanda, a private crops consultant and now also with Seed Consultants, Washington Courthouse, Ohio, decided to look further into the results. He expected 4 miles per hour to perform best, and it did as far as placement of seeds and absence of skips and doubles. However, even the numbers for planting correctness for 6 miles per hour, although significantly different than at 4 miles per hour, were sill very respectable.
Nanda noticed an increase in population for the 4 miles per hour plots. Statistics weren't applied to it, but he said it amounted to several hundred plants per acre. This plot was planted May 27, in a time frame considered late for the area. Average yields were still in the mid 190 bushels per acre range, however. There was adequate to excess moisture early, then a drought and very warm temperatures beginning in late July and continuing through harvest.
Nanda strongly believes that this may not have been the ear to have that many extra plants in the stand, especially in plots planted late, which still took the brunt of the hot dry weather during critical times of development. What's surprising, perhaps, is how well the plots yielded in spite of the planting date and conditions.
Nanda is a firm believer in maximizing plant populations to fit the soil type. However, he also believes that you can plant too thick if the soil type can't support it. He's learned that lesson working with gravelly soils, with and without irrigation. In those situations, the difference can be striking.
Nanda remains a firm believer in planting at a moderate speed. He still thinks that's important to getting a good sand of corn that's evenly spaced and that will emerge uniformly on time.