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Soil moisture deficits have eased slightly thanks to rains and snow

By Carol Stender
cstender@agrinews.com

Date Modified: 05/20/2013 9:31 AM

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LAMBERTON, Minn. —April and May snowstorms were almost too much to bear, but it was just what soil doctors ordered to ease dry field conditions.

According to soil measurements taken at the Southwest Research and Outreach Center in Lamberton, topsoil and subsoil moisture deficits have eased.

The overall average soil moisture deficits as of May 1 showed a 1.1 inch deficit in the upper three feet and a 1.6 inch deficit in the upper five feet of the profile, said SWROC soil scientist Jeff Strock. At this same time in 2012, the deficits measured 2.2 inches in the upper three feet and 3 inches in the upper five feet.

Extension educator Dan Martens hasn't taken measurements in Benton, Stearns and Morrison counties, but he said it was too wet to get into the fields.

"We've picked up some subsoil moisture, but we probably haven't recharged the whole profile," he said. "We need some timely rains as we go on into the growing season."

The three counties didn't weren't as dry as other areas in 2012, but moisture was a concern.

"Everybody is climbing out of this (drought) slowly," Strock said. "If you look at the drought monitor, there are these areas of extreme drought in the U.S. with a corridor of extreme drought that goes from the southwest to the northeast. But with the snow and the rains, we've seen some of those droughty conditions lessen in this area."

The National Weather Service's 60- to 90-day forecast calling for wetter than normal conditions came true, Strock said. The latest forecast calls for an equal chance of wetter or drier conditions.

While the recent snow and gradual melting have replenished moisture in the top three feet, more precipitation is needed to recharge the depleted soil water deep in the five-foot profile. He said the subsoil moisture can be thought of as soil water in reserve which can carry a crop through the dry periods of July and August.

It's important to save as much of the pre-plant soil moisture in storage as possible, Strock said. Reducing the number of tillage operations will help reduce moisture losses.

Crop residue management is also important. Maintaining crop residue at or near the soil surface for as long as possible will save soil moisture and reduce soil erosion.

Soil moisture is measured on the first and 15th of every month between April and November. Soil moisture is measured at six-inch intervals in the upper two feet of the root zone and again at one-foot intervals throughout the five-foot root zone.

The readings are available at the SWROC website at swroc.cfans.umn.edu.