Source: University of Minnesota

University of Minnesota corn population research finds that yield increases resulting from higher plant populations are primarily the result of increased light interception during grain-fill by the crop canopy.

Optimum plant population varies little with planting date or row width, but early-maturing hybrids may require a higher plant population than full-season hybrids.

While the economically optimum plant population varies according to the cost of seed and the price of corn, the plant population needed to maximize profitability ranges from about 32,000 to 34,000 plants per acre under current economic conditions.

Planting date has a large impact on yield. When compared to an early May planting date for a population of 32,400 plants per acre, results from 2008 at Lamberton and Waseca show that yield was reduced by 3 percent to 17 percent when planting was delayed until mid-May and late May, respectively.

Farmers will plant less acreage
USDA's Prospective Plantings report indicates that producers intend to plant less acreage this year than they did in 2008.

Planting intentions for all crops included in the March survey are 7.8 million acres less than the acreage seeded to those crop the year before. Including acreage of hay intended for harvest, the decline is about 7.6 million.
Declines total 4.5 million for wheat, 1.3 million for sorghum, nearly 1 million for corn, 154,000 for canola and 446,000 for sunflowers.

For wheat, 75 percent of the acreage reduction is for winter wheat.

Working wet soils can cause problems
Many good management options exist for continuous corn, says Gary Hall, with Cerro Cordo County Extension.

Conventional tillage probably isn't one of them.
We all know the horror stories of what happens when wet soil is tilled. Compaction, clods in the seedbed, side-wall compaction, and perhaps potassium deficiency due to compaction can arise when soil is worked too wet, Hall said.

If soil stays wet in poor drainage, bottomland and higher clay-content areas, run the planter empty with row cleaners to move residue aside, he suggested. This option removes residue and exposes the soil surface without excessive tillage compaction and soil smearing.

Phosphorus more important than ever
It's more important than ever to have a very high soil test for phosphorus, says Gyles Randlall, agronomist at the Southern Research and Outreach Center in Waseca.

New University of Minnesota research at Waseca shows that soils with a very high P test (Bray P-22 ppm)