The National Weather Service has long made predictions about rain, snow and ice.

Now add manure to the list.

No bull.

It’s part of a serious and welcome effort to better protect Wisconsin lakes and streams — as well as farmers’ bottom lines.

The National Weather Service plans to update its “manure advisory” forecasts three times a day at www.manureadvisorysystem.wi.gov. An online, color-coded map (no, they didn’t use the color brown) will alert Wisconsin farmers to conditions and days that are good or bad for spreading manure, so it doesn’t wash off fields into waterways.

The latest map Thursday showed most of the soil across Wisconsin is still frozen this winter. That limits the ability of any manure that’s spread to infiltrate the ground. The map also cautioned farmers across most of south-central Wisconsin and Dane County against spreading manure over the next 10 days, citing a high risk of melting snow.

When manure washes off a field and into a stream, it can kill fish and other aquatic life. And when manure washes from streams into lakes, the nutrients promote weeds and algae blooms come summer.