The art of farming, underwritten by science

On August 20th, 2010 - a typical sultry summer day in North West Iowa, over sixty people sat on rows of grain stalk blocks in the shade of a large metal building, part of the Iowa State University Allee Research and Demonstration Farm near Newell. We assembled there to learn how to farm more efficiently and more successfully by using the most advanced research and field work presented by the ISU scientists for Corn and Soybean Initiative, and relying on the newest guidance systems and equipment available. While the light breeze wafting through the building made all comfortable, the morning presentations were neither light nor breezy. It was a serious learning affair. Roger Elmore ISU Extension corn specialist led a very crisp and clear discussion of planting dates appropriate for our area, their dependence on soil temperatures (near 50 degrees Fahrenheit, and expected to rise), and approximate optimal calendar window (between April 20th and May 5). We learned that planting corn too early, rather than too late is better for corn yields; however, planting past mid-May requires selection of some shorter maturity hybrids.

Based on specific field conditions, genetics, and environments, the optimum variation in seedling rates in Iowa is between 28,000 and 42,000 seeds per acre. Furthermore, planting an average of 35,000 seeds per acre will produce maximum yields, and seedling rates should be reduced if soil conditions are poor, or water presents limitations. Corn development, and possible insect infestation are predictable from observations of heat accumulation by measuring daily air temperatures from base temperature of 50 degrees Fahrenheit, to shoot emergence at approximately 125 DD (where "DD" stands for degree days calculable from a table given as example on p.9 of the ISU Extension "Corn Field Guide" which was available free of charge to all the attendants at this Field Day).

Allison Robertson, ISU Extension plant pathologist, followed Roger Elmmore's presentation with her report on the current findings about SDS (Sudden Death Syndrome) disease of soybeans. This disease, one of 23 non seed-borne, is caused by a fungus (Latin name: Fusarium solani) f.dp.glycines.

This fungal pathogen infects the roots of soybean crop within a few days of germination and, at flowering, the fungus produces toxins which wilt and brown the leaves. Its growth is favored by high moisture and cool soil at soybeans early growth. By first week of August SDS becomes visible on infected plants.

Read more of this story in the August 28 Pilot Tribune.

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