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Researchers: band-applied fertilizers can boost early corn development

Placing fertilizer in a band at planting is an appealing option for growers who wish to optimize yields while keeping input costs at a minimum.

When fertilizer is banded, soil "tie up" of several nutrients is reduced, since soil to fertilizer contact is minimized. This results in more efficient use of these nutrients by corn.

Starter fertilizer can also be a boost for corn under stressful conditions. A shift to earlier planting dates, reduced tillage and corn-on-corn acres has led to renewed interest in the use of band-applied or starter fertilizers.

Traditionally, starter fertilizer was banded two inches to the side and two inches below the seed (2x2). Since many planters today are not equipped for this placement, other options, such as placing liquid starter fertilizers with the seed or dribbling them on the soil surface -- two inches to the side of the seed row (2x0) at planting -- are being used.

Over the past three years, research conducted by Gyles Randall and Jeff Vetsch at the University of Minnesota (U of M) Southern Research and Outreach Center in Waseca found that yield results were similar among 2x2 and 2x0 placement methods. Yields were greatest for these placement methods when sulfur was included in the application, with yields averaging 18 bushels per acre over the control in 2006, and 12 bushels per acre more during the three-year study period.

Historically, research indicated little advantage for sulfur fertilization in corn. During this time, however, the atmosphere also supplied more sulfur (think acid rain). Recent research suggests that the addition of sulfur to a starter fertilizer may provide a yield boost for some growers.

Application method and source is important when sulfur is applied at planting. When potassium thiosulfate was applied directly with the seed (also known as a "pop-up" application) at four pounds of sulfate per acre, stand was reduced by 30%, and yield was reduced 13% in one of the three years during the U of M trials. As a result, this product would not be recommended at this rate in contact with with the seed.

Particularly in sandy soils, ammonium thiosulfate (another sulfur source) can have a negative impact on germination. In general, the potential for damage from seed-placed fertilizer increases under dry conditions at planting, which is also of particular concern with sandy soils.

In U of M research, no correlation has been found in between soil test values for sulfur and a yield response. The potential for a response to sulfur fertilization is also greatly reduced if manure has been applied to a field.

Placing fertilizer in a band at planting is an appealing option for growers who wish to optimize yields while keeping input costs at a minimum.

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