In 2009, the Iowa Legislature passed a bill pertaining to winter application of manure on snow-covered and frozen ground. The rules enforcing that legislation were completed earlier this year and went into effect on Sept. 15, 2010. This law applies to liquid manure from confinement feeding operations that have more than 500 animal units in confinement. This law does not apply to: manure from open feedlots dry manure (frozen manure is not dry manure) liquid manure from small animal feeding operations (confinements with 500 animal units or less) liquid manure that can be appropriately injected or incorporated on the same date of application