Corn yield enhancement through planting densities and nitrogen management – Part 3

Row spacing effects on corn yield of two hybrids were inconclusive in 2013.

There is considerable interest in increasing corn yield in the short term by growing modern hybrids at higher than normal populations in narrow row configurations and with adequate nitrogen (N). Modern hybrids by virtue of their improved stalk strength and robust root systems may be more amenable to narrow rows compared to the conventional 30-inch spacing. The 20-inch row system provides more space within the row for a given population rate compared to the 30-inch system (Table 1). However, the 20-inch row system requires additional investments in machinery for planting, harvesting and nitrogen sidedressing.

Table 1. Within row plant spacing in 30-inch rows compared to 20-inch rows.

Population

Within row plant spacing (inches)

30-inch row

20-inch row

30,000

7.0

10.5

36,000

5.8

8.7

42,000

4.8

7.5

In 2013, two hybrids, DKC48-12 and DKC49-94, having insect and herbicide stacked technology and improved drought-tolerance capabilities, were tested at three population densities of 30,000, 36,000 and 42,000 plants per acre; two row spacings of 20 inches and 30 inches; and two nitrogen rates of 120 pounds per acre (low) and 240 pounds per acre (high). The DKC 48-12 is known to be a flexed type compared to DKC49-94 which is considered a fixed type. Treatments were replicated three times for each hybrid.

The response of the two hybrids to population size and nitrogen rates was discussed in Part 1 and Part 2  of this series. In this article, the row spacing effect is discussed.

The average corn yield of both hybrids was higher at 20-inch row spacing compared to 30-inch row spacing (Table 2). The row spacing effects appeared to be more pronounced in DKC49-98 (9.7 bushels per acre) compared to DKC48-12 (about 4.9 bushels per acre). The yield differences to row spacing were not statistically significant. This may be in part due to row spacing treated as the main plots in the split-split plot experimental design and the need for a greater yield differences to produce significant effects.

Table 2. Effect of row spacing on two corn hybrids, DKC48-12 and DKC49-94, at Mason Technology Center, 2013.
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These observations relate to one year and there is merit to testing over several seasons as transitioning to a 20-inch row system involves investments in new equipment and cultural practices.

Other articles in this series:

This project was funded by Project GREEEN. I wish to thank the Dekalb/Asgrow staff at the Mason Technology Center for their collaboration with Michigan State University Extension and providing seed, equipment and labor for this study.

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