Similar Population Study Finds Different Results

Soil type, rainfall conditions make the difference.

Published on: Jan 26, 2009

The full story will be revealed in your February issue of your Farm Progress state magazine if you live in the Midwest. The best yields in the population study in the Corn Illustrated plots last summer came at around 27,250 plants per acre, actual harvest stand, for both hybrids. Top yield was in the 140 bushels per acre range.

However, you will discover that the field was hit with torrential rain early, some 20 inches or more in the first six weeks after planting, then dry weather later. The dry weather came in August, and the plot soils are loams over gravel at only three feet deep. Dave Nanda, the plant breeder and agronomist who assisted with the study, says that the results apply to that field in that year- last year.

Now come results form a somewhat similar study conducted by Indiana Prairie Farmer and the Tippecanoe County Extension Service in Tippecanoe County, Ind. The plot was planted at the Throckmorton Research Farm south of Lafayette, Ind. Field work was completed by staff of the farm. The farm is operated as a research farm by Purdue University. The soils are deep, and are right at the edge of the prairie. While gently rolling and still timber soils, organic matter content was much higher than for the soils near Edinburgh, Ind., where the actual Corn Illustrated plots were located.

Jeff Phillips, Extension ag educator in Tippecanoe County, oversees the plots. The same two hybrids were used as were used in the Corn Illustrated plot. The seed was donated by Bird Hybrids, Tiffin, Ohio. However, each treatment consisted of half one hybrid and half the other. The two hybrids were not harvested separately in this study.

The results were different, as you might expect. Yield at 26,000 seeds per acre dropped at planted ran nearly 20 bushels per acre lower than the top yield, which topped 190 bushels per acre. The three higher planting rates, form 30,000 up to over 35,000, produced roughly the same yields. The actual highest yield was at 32,000 seeds per acre, but when averaged over four replications, the difference was minimal.

This trial also compared starter fertilizer vs. no starter at each of the four populations. While starter fertilizer did better at some populations than others, overall, the average yield increase for applying starter was only about four bushels per acre.

This plot confirms several points. First, location and weather conditions can play a big role in the outcome of even similar trials. That's why researchers want to test hybrids, varieties and practices at as many locations as possible. Second, 30,000 to 35,000 seeds per acre produced similar results. And third, once again, while corn receiving starter looked much better earlier in the season, the payoff was marginal at best once the combine ran across the field.

Stay tuned for further updates on this plot.