Strip-tilled corn yielded more than 3 tons per acre than no-tilled and zone-tilled in a 2011 research study by the University of Vermont.

While the difference was not statistically significant, strip-tilled corn yielded 16.9 tons per acre vs. 14.0 tons per acre for zone-till and 13.9 tons per acre for no-till.

When harvested in October, the strip-tilled corn had a final stand of 26,717 plants per acre, vs. 25,555 for no-till and 23,329 for zone-till. Dry-matter content was virtually identical for strip-tilled and no-tilled corn, while less for zone-tilled.

Strip-tilled: 48.7% dry matter
No-Tilled: 48.4% dry matter
Zone-tilled: 46.1% dry matter

More Detail

The University of Vermont Extension’s Northwest Crops and Soils Program conducted the corn trial at Borderview Farm in Alburgh. The soil was a rocky Benson silt loam.

The corn was planted into a winter-rye cover crop. There were four replications of the plots, which were 45 feet long. The three different tillage treatments were all planted with Mycogen TMF2Q298, an 89-day relative-maturity hybrid, at 34,000 seeds per acre on May 31.

The strip-till plots were prepared with a Blu-Jet Coulter Pro and planted with a John Deere 1750 corn planter. The no-till plots were planted with a John Deere 1750 corn planter, and the zone-till plots were planted with a White 6100 zone-till planter.

The strip-till and no-till plots each had four 30-inch rows and were 12 feet wide. The zone-till plots had six 30-inch rows and were 15 feet wide. A 10-20-20 starter fertilizer was applied at 260 pounds per acre to the strip-till and no-till plots. A liquid 9-18-9 starter fertilizer was applied at 5 gallons to the acre in the zone-till plots. A pre-plant glyphosate application was made at a rate of 2 quarts per acre to all plots.

Ammonium sulfate (21-0-0) was sidedressed at a rate of 100 pounds available nitrogen per acre on July 8, according to results from a pre-sidedress nitrate test. Populations were again counted immediately before harvesting the corn plots on Oct. 7.

The 2011 growing season included many weather extremes in Vermont. In April and May, excessive rainfall left soils saturated and, in many cases, delayed planting. June and July, in contrast, were hot and dry. July had 0.29 inches less precipitation than the 30-year average. In August, precipitation levels were extremely high (10.23 inches for the month, which is 6.38 inches above average). Tropical Storm Irene brought severe wind and record rainfall.

Strip-Till Reduces Yield Drag

Corn silage quality was not affected by tillage method in this trial. Trial averages were comparable to corn grown using conventional tillage practices.

The harvest population was very low — 25,500 plants per acre — compared to the initial seeding rate of 34,000 plants per acre. Reduced plant populations may have been a result of poor germination. Reduced tillage fields have been noted to be colder and wetter as compared to conventional tillage. These environmental variables could easily cause reduced populations.

The average yield was 14.9 tons per acre, which is low compared to yields of corn with similar relative maturity planted conventional tillage. This indicates that corn yields may be reduced in first years of transition to reduced tillage practices.

Although not significant, it does appear that strip-till systems may help alleviate some yield drag often seen when transitioning to reduced tillage. Additional years of reduced tillage trials in this area will help determine if yield drag will be reduced as soil health improves as a result of this practice.