ANALYSIS-America's breadbasket banking on April showers

* Soil moisture levels improving

* More snow or rain needed

* Above-average rains needed into spring

* December winter storms stir optimism

CHICAGO, Jan 23 (Reuters) - Farmers in America's corn belt are counting on spring rains to recharge reserves that were drawn down during last year's worst drought in over a half century, which left soil moisture in top producer Iowa at a 27-year low as the new year begins.

Soil moisture has improved from the drought-depleted lows in the eastern growing region. But levels remain very low in the west, putting farmers, buyers and the markets on edge as the spring planting season looms less than three months away.

"We're extremely concerned as to what spring weather will bring. Our snowfall has been very minimal here in northwest Iowa at only about 5 inches, a third or less of what we usually would have by this time of the year," said Bill Tentinger, a corn and hog producer from Le Mars, Iowa.

Agricultural meteorologists say they see no signs of relief from the drought in roughly the western half of the Midwest, including the area west of the Mississippi River, painting an ominous picture for 2013 crop production.

"Dry weather will prevail in core drought areas of the western Midwest and Central Plains through the last half of January," said Joel Widenor, agricultural meteorologist for Commodity Weather Group.

"Currently we don't see a whole lot of change. The pattern for the next 30 days is a quiet one for the Plains and the western Midwest. It's not a good forecast"

Widenor said below-normal rainfall was expected from March to May in the Plains and almost all of Nebraska, South Dakota, Minnesota, Iowa, northern Missouri and eastern North Dakota.

He said better crop weather, including more rainfall, was expected in the eastern Midwest, including Ohio, Indiana and southern Illinois.

Cropcast meteorologist Don Keeney told the Reuters Ag Forum last week that the western Corn Belt needs roughly 12 to 18 inches of rain to ease the concerns about dryness.

"That's a lot of rain needed in a short time, so the odds of that region fully breaking the drought before planting season is, of course, rather low," Keeney said.

SOIL MOISTURE CRITICALLY LOW

At the end of December, soil moisture in Nebraska was at a 27-year low, a tenuous 53 percent of the average, based on data from the National Oceanic and Atmospheric Administration and analyzed by analytics firm Lanworth, a unit of Thomson Reuters.

The moisture level in Iowa was 75 percent of the average since data began to be compiled in 1985, In Minnesota it was at 77 percent, Illinois 86 percent and Indiana 89 percent, according to Lanworth.

"Nebraska needs significant precipitation over the next several months. All Indiana needs is a little rain to get back to normal but Nebraska needs a lot of rain," said Andy King, Lanworth senior analyst of agriculture research.

He said rains in Indiana and Illinois likely boosted the soil moisture level from the end of December. But "much of Iowa, Minnesota and Nebraska received much less precipitation and the drought remains severe," King said.

Tentinger, who feeds the corn he grows to his hogs and also buys additional corn, said "there already is talk about some farmers not planting corn on corn (fields) due to the increased moisture usage of corn versus soybeans."

CROP PRODUCTION PROSPECTS ON EDGE

Without above-average moisture, spring-planted corn and soybean crops will be slow to germinate and grow.

Bob Nielsen, agronomist for Indiana's Purdue University, said it takes about 20 to 25 inches of moisture to produce a corn plant, from planting to maturity. "Last year in two of our research locations corn received only 8 inches of rain, compared with the normal 20 inches," he said.

Nebraska, Iowa, Illinois, Minnesota and Indiana are the top five corn states, producing 60 percent of the nation's 10.7 billion bushel crop last year, despite the drought.

Mark Bernard, an agronomist for Agro-Economics Inc, in New Richland, Minnesota, said the dry soils have "everyone concerned." But he added that "we also know that it can change in a hurry. We saw that over the past year."

Soil moisture levels in south-central Minnesota, the big crop region in the state, are less than half of normal, he said.

"We're looking at 2 to 3 inches of available moisture in the top 5 feet of soil and most of that is in the top 12-18 inches," Bernard said. "Typically there would be 7 to 9 inches available moisture, so we're well below 50 percent of normal."

TIGHT STOCKS DRAWS FOCUS TO WEATHER

The tight corn stocks scenario has drawn increased attention to Midwest weather patterns ahead of the upcoming sowing season. The U.S. Department of Agriculture has forecast the supply of corn in the United States to fall to the lowest level in 17 years by the end of this summer.

Some snowfall in December helped, but snowpack and rainfall remain far short of what is needed to recharge depleted soil moisture reserves.

Don Roose, president of U.S. Commodities, in Des Moines, Iowa, said the December snowfall would not eliminate the drought, though it did help generate some optimism.

However, "the December storm and big snow is something we didn't see all of last winter, so we're hoping that maybe this is a sign the weather pattern is changing."

The latest U.S. drought monitor report showed nearly 60 percent of the contiguous United States was in at least "moderate" drought as of Jan. 15.

(Reporting by Sam Nelson; Additional reporting by Karl Plume and Andy King in Chicago; Editing by Dan Grebler)