Skip-row corn stabilizes dryland grain yields
Panhandle farmers have been growing more dryland corn in recent years, encouraged by good crop prices and timely rains. However, the production of corn in the Nebraska Panhandle without irrigation is a risky business. One way to help manage the risk is to use skip-row planting patterns.
As a result of research conducted by the University of Nebraska-Lincoln from 2004 to 2006, we can make some recommendations about skip-row planting patterns for dryland corn. The recommendations vary with the expected yield.
Panhandle dryland corn acreage has varied from a low of about 10,000 acres in 1995 (prior to the 1996 farm bill), to a high of about 96,000 acres in 2000, the beginning of the eight-year drought. By 2005, dryland corn acreage had fallen to just 22,000 acres. Acres rose to 93,000 in 2011.
Continued strong corn prices could see dryland corn acres in the Panhandle exceed 100,000 for the first time.
Twenty-three field trials were conducted to compare skip-row planting to conventional corn planting from 2004 through 2006 across Nebraska, western Kansas and northeast Colorado. In Nebraska, trials were located from Mead in the east to Scottsbluff in the west. Soils ranged from silty clay loams to very fine sandy loams.
Roundup Ready corn hybrids adapted to the location were no-till planted into the preceding crop residues. Nitrogen fertilizer was applied in all studies based upon soil nitrate tests and expected yields.
All trials were conducted without irrigation (dryland) and consisted of four planting patterns and three plant populations. Planting patterns were:
--The standard planting pattern, consisting of planting every row using a 30-inch row spacing;
--Plant two rows and skip one row;
--Plant one row and skip one row (single skip-row); and
--Plant two rows and skip two rows (double skip-row).
Plant populations were selected to represent a broad range of recommended populations for an area. In western Nebraska and Kansas, plant populations were 10,000, 15,000, and 20,000 plants per acre; in eastern Nebraska, 15,000, 22,500, and 30,000; and at Akron, CO, 8,000, 12,000, and 16,000.
The purpose of including various plant population treatments was to understand how plant population interacted with planting pattern. But study results did not show a strong link between these factors.
Relative yield of the various skip-row planting patterns were compared and related to the standard planting pattern for each site and across all 23 trials. In lower-yielding environments, skip-row planting patterns improved grain yield compared to the standard planting pattern.
The data indicate that in lower-yielding environments, the gain from using the double skip-row pattern will likely be greater than for the other skip-row patterns, but in higher-yielding environments, the probability and extent of loss relative to the standard planting pattern would be greater.
The benefits of skip-row planting patterns for stabilizing dryland corn grain yields should be considered by all dryland growers in the Central Great Plains west of 101 degrees W longitude.
Risk-averse growers will see the greatest reduction in yield variability with the double skip-row pattern, while growers with moderate risk-aversion may wish to consider the single skip-row pattern. We recommend using either of these two patterns when grain yields are expected to be less than about 75 bushels per acre.
If yields are expected to fall between 75 and 100 bushels per acre, growers may consider using the single skip-row pattern. For areas with yield potentials of greater than 100 bushels per acre, growers should use standard planting patterns. We did not see sufficient response to planting two rows and skipping one row to recommend its use instead of the standard planting pattern.