High yield corn production can result in high nitrogen use efficiency

Alarm is expressed about the environmental impact of the increasing amount of reactive N in the atmosphere and in terrestrial and marine ecosystems around the globe. Much of this increase is attributed to production and use of N fertilizer. Use of fertilizer N is essential to meet growing global demand for agricultural commodities. Management is key to increasing productivity while also increasing N use efficiency and reducing N losses. A team of University of Nebraska-Lincoln scientists, with partial funding from the Nebraska State Legislature, addressed this challenge. They conducted 32 irrigated trials across diverse production conditions of Nebraska from 2002 to 2004 to evaluate corn response to rates of split-applied N. The results were reported in two papers published in the January-February 2011 issue of Agronomy Journal. The results demonstrate the potential to achieve high N use efficiency by corn in high yield situations, compared with typical efficiencies, provided N was applied near the economical optimum N rate. Several factors contributed to high fertilizer N recovery: no fall N application; split application of N; avoiding sites prone to water-logging and leaching to minimize nitrate-N losses; crop management to have a healthy crop with a vigorous root system efficient in both nutrient uptake and conversion of nutrients and carbohydrates to grain; and irrigation management to avoid leaching and denitrification losses and to avoid crop stress