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Something old, something new

By Staff | Jul 2, 2015

MARK LICHT, a cropping systems analyst at ISU’s agronomy department, presents what research has shown in how corn yields are affected when planted at high populations in narrower rows.



KANAWHA – There was something old and something new for farmers and anyone else interested in crop production at Iowa State University’s Northern Research Farm field day June 25 in Kanawha.

The “old” portion covered increasing yields, fertility, and the perennial problem of weed control.

Something “new” told of ISU’s research into raising crops for energy, which is in its early phases.

EMILY HEATON, an ISU Extension agronomist, explains her progress in developing crops that can be grown for energy.

Mark Licht, a cropping systems analyst at ISU’s agronomy department, discussed the possibility of increasing corn yields by going to narrower rows with higher populations.

Licht said tests run at ISU’s research farms have shown no correlation between yield and row spacing.

When planting higher corn populations, selection of suitable hybrids for increased population is important, Licht said

Higher levels of inputs such as seed and fertilizer will help increase yields, but after a point, the yields level off and additional inputs are merely increased expense with no additional return.

Weed control

Paul Kassel, an ISU Extension field agronomist, talked about weed control and listed herbicide options for soybeans.

The options were preplant incorporate, pre-emergence, early post-emergence and post-emergence residual.

An effective weed control program will use two or three of these options, Kassel said.

Because weeds are increasing their tolerance for Roundup, with water hemp being the main problem, Kassel said, herbicides are becoming more potent.

Using a mix of two or more to increase effectiveness.

Increased rates of application are creating problems with herbicide carryover and crop burning.

“We are back to the old days,” said Kassel. “You will have to burn your beans, some time, somewhere.”

The burning will result in little or no yield reduction, according to Kassel, and spraying is a matter of the sooner the better.

Nitrogen use

John Sawyer, a fertility specialist in ISU’s agronomy department, addressed nitrogen use.

Sawyer said studies determined yields on fields with no application of nitrogen.

An absence of nitrogen produced 50 to 60 bushels of corn per acre on continuous corn and 110 to 120 bushels of corn per acre in corn after soybeans.

Besides increasing yields, nitrogen application is beneficial in building soil organic matter through microbial action.

Without additional nitrogen, there would be a depleting effect on soil, Sawyer said. “It’s a long-term process. We can’t control the soil system as it is open to air and water.”

Unfertilized fields will have nitrogen runoff measured at 7 parts per million, while the government standard for drinking water is 10 parts per million.

Cover crops can reduce nitrogen runoff by 30 percent with perennials being the surest way to reduce the loss.

But there is no market for perennials.

Bio-reactors are the next best solution to reduce nitrogen loss under conditions of high production.

Biomass energy

Emily Heaton, a member of ISU’s agronomy department, said her responsibility is in developing crops for energy usage.

The program is in early stages, she said, with miscanthus grass showing promise as a source of biomass energy.

Miscanthus grass is a native of Asia, yields 8 to 10 tons of biomass per acre and is harvested in March.

At 10 percent moisture, it has a heat value of 7,200 BTUs per pound.

Switchgrass, at 15 percent moisture, has a heat value of 7,500 BTU/lb.

Perennial crops have potential as a biomass source, plus have benefits of reducing soil and water movement with retention of nitrates and phosphates.

Heaton said biomass crops should start on a small scale on 10 to 15 percent of cropland, planted in underperforming parts of a field.

She said the main problem with perennials is in getting them established with a planting cost of $1,000 an acre.

Perennials have a life span of 20 years.

Another problem to be solved is the lack of a market for them.

She has been working with a biomass project at the University of Iowa power plant to increase its usage of biomass.

The U of I power plant spent $3 million to develop a way to burn oat hulls, a waste product from Quaker Oats in Cedar Rapids, resulting in a savings of $10 million.

Heaton said her job of identifying small pieces, such as finding suitable crops or creating a market, is not a problem. The difficulty is putting all the pieces together.

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