For corn, using dairy manure and legume cover crops in crop rotations can reduce the need for inorganic nitrogen fertilizer and protect water quality, but these practices also can contribute to emissions of nitrous oxide — a potent greenhouse gas. Read more in this story from the Altoona Mirror (Altoona, PA).

Most farmers value soil health in theory, but few studies have worked to place an actual agronomic value on soil health. A study found that a 10% improvement in certain soil health measurements increased relative yields by an average of 5% across N fertilizer rates. Read more in this article from Ohio's Country Journal.

Researchers in Penn State's College of Agricultural Sciences have developed an important component of a new system that corn growers can use to adjust nitrogen fertilizer applications based on site-specific measurements of cover crops and soil organic matter. The development is notable because while the wide use of cover crops in rotations with corn in the last decade has resulted in reductions in nutrient pollution and sedimentation, the introduction of cover crops has muddled growers' decision-making regarding how much nitrogen fertilizer to apply to meet their cash crop demands. Read more in this press release from Penn State University.

Balancing the supply and demand of nitrogen (N) in crop production is challenging. In most cases, application of N fertilizer is needed to ensure that adequate N is available to corn. Nitrogen that is not taken up by plants can be lost from cropping systems as nitrate through leaching or runoff, according to this article from the University of Minnesota Extension.