ROCKVILLE, Md. (DTN) -- This year's challenging growing season will trim production across the northern Corn Belt this year, as corn and soybean yields in Iowa, Minnesota and Wisconsin slip lower in 2019.

The DTN/Progressive Farmer 2019 Digital Yield Tour, powered by Gro Intelligence, is an in-depth look at how the 2019 corn and soybean crop is progressing using Gro's real-time yield maps, which are generated with satellite imagery, rainfall data, temperature maps and other public data.

Gro's models suggest Iowa's corn crop will make an average yield of 187 bushels per acre (bpa), down 9 bpa from last year and also below USDA's August estimate of 191 bpa. Gro pegs Minnesota's average corn yield at 175 bpa and Wisconsin's at 167 bpa, both down from last year's crops, though slightly above USDA's August estimates.

For soybeans, Gro forecasts Iowa's statewide yield at 53 bpa, down 5 bpa from last year and also slightly below USDA's August estimate of 55 bpa. Gro forecast Minnesota's statewide soybean average at 44 bpa and Wisconsin's at 46 bpa, both below last year's soybean production but close to USDA's August estimates.

You can see specific comparisons in these charts:

Iowa: https://app.gro-intelligence.com/…

Minnesota: https://app.gro-intelligence.com/…

Wisconsin: https://app.gro-intelligence.com/…

Gro's county and state yield estimates update on a daily basis, so the numbers at publication time may differ slightly from what you find on the Gro website.

IOWA

With a statewide average of 187 bpa, Gro's models show Iowa with the highest corn yield potential of the 10 states included in DTN's Digital Yield Tour. While the yield potential is strong, it sits well below USDA's 196-bpa estimate last year. The symptoms of a wet spring are visible not only in this year-over-year difference, but also on another map known as the normalized difference vegetation index (NDVI), which uses satellite imagery to show how abnormally dry or lush an area is, using a 10-year average "greenness" index.

The March-to-May time frame was the ninth wettest in Iowa's history, but it hit different parts of the state at different times, noted DTN Senior Ag Meteorologist Bryce Anderson.

"Western Iowa caught the first round of flooding with the central U.S. bomb cyclone in mid-March. Then, in early May, eastern Iowa was the recipient of heavy rain and late-spring snow melt, which brought on flooding that rivaled the 1993 Great Flood year," Anderson said. "May loaded up on moisture; May precipitation was the fourth-wettest on record. Temperatures were also below normal. This was the ideal combination for extensive loss of acreage due to flooding and ponding out. That's exactly what happened; NDVI vegetation index maps show wet-ground impact statewide."

The flooding impact was strongest in the state's southeast and far southern counties, two areas that had record precipitation in May. You can view Iowa's NDVI map here, where brown shading indicates a lack of vegetation: https://app.gro-intelligence.com/….

Gro Intelligence's yield maps show corn yields ranging from 207 bpa in Shelby and Cherokee counties in western Iowa to a low of 140 bpa in Wayne County along the southern border with Missouri. You can see the county level map here: https://app.gro-intelligence.com/….

Mike Berdo got about half of his corn crop planted in mid-April, but then it didn't stop raining until the end of May. His farm received 20 inches of rain in May, and there's a distinct difference between what was planted early and late.

"Early planted corn looks really good. It's no 2017 crop, but for 2019, it's going to be good," he said, estimating that the potential difference between early and late-planted corn is 50 bpa or more.

On soybeans, Gro's county maps show a 20-bpa difference between the highest-yielding counties and the lowest. Cherokee and Plymouth counties have the highest average yield at 61 bpa while Ringgold has the lowest at 41 bpa. While the state estimate is only 4 bushels below USDA's final number last year, the county map shows a lot more variation, particularly in the eastern part of the state.

Berdo said soybeans show the worst of this spring's wet weather. A lot of farmers like himself mudded them in, but others had to take prevented planting.

"It was just that time of year, we had to go and ground conditions were not ideal," he said. "I think we're going to see below trend line yields on beans in my area."

In Washington County where Berdo farms, Gro estimates soybeans will yield about 48 bpa. While they've had a few small showers in recent weeks, the last measurable rain was 1.2 inches a month ago during the county fair. "The beans really need a rain," Berdo said.

Ultimately, both Iowa's corn and soybean crops have miles to go before harvest, added DTN's Anderson.

"The late start means late development. Corn is only around 41% in the dough stage, and the soybean pod-setting rate is some 25 to 30 percentage points behind average," he said. "Progress is running around two weeks later than average. There is no question that crops will need to avoid an early freeze this fall."

MINNESOTA

Gro puts Minnesota's statewide corn yield average at 175 bpa, right now, with its soybean average hovering around 44 bpa. Both are significant drops from last year, when USDA pegged corn at 182 bpa and soybeans at 50 bpa.

As with Iowa, the toll of spring flooding and rainfall on Minnesota farmland is etched into Gro's real-time maps.

"The vegetation display over the western third of the state is astounding," Anderson noted of the NDVI map of the state, which shows the relative greenness of each state's vegetation. "Almost the entire length of the border with South Dakota, and extending about 100 miles into the state, flooded-out and ponded-out acreage is widespread." See the map here: https://app.gro-intelligence.com/….

Minnesota farmers reported nearly a million acres of prevented corn planting to USDA's Farm Service Agency, as well as more than 170,000 prevented planting soybean acres.

Many appear to be concentrated in the southwest and southeast corner of the state, according to Gro's maps, which show brown shading across those regions, indicating a lack of vegetation. What did get planted is dealing with a twofold threat of poor planting conditions and delays, added Anderson.

"In the western and southwestern counties, precipitation was either record-wet or near-record-wet for the three-month period," he said. "So, not only did planting take place late, but, except for a very hot spell in July, temperatures have been on the cool side, which has progress lagging the average pace by around two weeks."

Gro's county-level yield maps echo these conditions. (See them here: https://app.gro-intelligence.com/…). Last year, Gro maps showed counties in the southern third of the state with corn yields ranging from 190 to 200 bpa. This year, yields in that southern third are far more variable and lower, ranging mostly from 150 to 190 bpa. Across the rest of the state, yields appear to have been trimmed by 10 bpa or more from last year's. The lowest corn yield average sits in Aitkin County at 110 bpa, with the highest falling in Martin County at 199 bpa.

Where Mark Nowak farms in the southernmost county of Faribault, Gro maps suggest yields will land around 197 bpa on average, down from 200 bpa last year. Potential was actually far higher than that, Nowak noted, before a terrible windstorm ripped through southern Minnesota and caused widespread green snap. "I am averaging 18% of plants damaged to some extent," he said. "I think millions of bushels of corn were lost in this region."

Gro's soybean maps tell a similar story of trimmed yields. Last year, most soybean yields in the southern half of the state fell between 40 to 60 bpa. This year, county-level maps show a wide variation of bean yields for this region, ranging from 35 to 45 bpa, with only a handful of counties in the southern third breaking past 50 bpa. Crow Wing County is pegged at the lowest yield average at 33 bpa, with Winona County taking the highest potential yield average of 53 bpa.

Justin Honebrink, who farms in Otter Tail County in west-central Minnesota, said Gro's prediction of 44 bpa for his county average, down 2 bushels from last year, sounds about right. "Soybeans just look so behind -- they would look really good if it was a month ago," he said. "A lot of guys were two to three weeks late getting beans planted."

WISCONSIN

In Wisconsin, Gro's models are predicting a 166-bpa average corn yield and a 45-bpa average soybean yield, down from USDA's final 2018 estimates of 172 bpa for corn and 49 bpa for soybeans.

As with Minnesota, Gro's real-time maps highlight how much smaller and later corn and soybean crops growing in Wisconsin are this year. The NDVI map of the state (see it here: https://app.gro-intelligence.com/…) shows dark patches of unplanted vegetation scattered across the state, but concentrated in north-central region and the eastern third of the state.

"Spring precipitation was the eighth-wettest in 125 years of record keeping, with the north-central swath having record-wet conditions," noted DTN's Anderson. "There are many acres of flooded-out or ponded-out land showing up in the NDVI depiction." The state's farmers have reported nearly half a million prevented planting corn acres and over 125,000 prevented planting soybean acres this summer.

The effect on yields are clear in Gro's county-level yield maps for corn and soybeans. See them here: https://app.gro-intelligence.com/…. Last year, Gro maps showed solid corn yields in the southern third of the state, mostly falling between 160 and 190 bpa. This year, yields have been trimmed significantly in this region and fall mostly between 155 bpa and 180 bpa. For example, the southwestern county of Grant averaged 202-bpa corn last year -- this year, Gro maps suggest fields there will be lucky to average 177 bpa. Iron County is showing the state's lowest potential yield average, at 97 bpa, with Lafayette County showing the highest, at 189 bpa.

In soybeans, a similar picture unfolds, with yields trimmed across most of the state. Last year, Gro maps show 2018 bean yields in the southern two-thirds of the state ranging from 40 to 60 bpa. This year, the real-time county maps for this region show soybean yields falling mostly between 30 and 50 bpa. The lowest yield average hails from Taylor County at 34 bpa, with the highest yield average of 57 bpa falling in Lafayette County.

These crops are also racing Mother Nature, noted Anderson. "It's going to be a race to the finish line for crops; in fact, as of Sunday, Aug. 11, Wisconsin still had 28% of its corn yet to pollinate, with soybean pod setting some 25% to 30% behind average," he said. "Fortunately, the weather forecast for September is pointing toward above-normal temperatures."

Thursday, the "tour" will explore the Eastern Corn Belt states of Illinois, Indiana and Ohio, which saw some of the worst rain and flooding this spring. If you would like your yield or field observations included, email DTN using the contact information below.

ABOUT THE TOUR

The DTN/The Progressive Farmer 2019 Digital Yield Tour, powered by Gro Intelligence, is taking place Aug. 13-16 and provides an in-depth look at how the year's corn and soybean crops are progressing. Each day, we'll feature crop condition and yield information from various states, which include links to the Gro yield prediction maps for those states. Yield summaries are viewable at the county level.

The "tour" started in the west, with the first day's articles focusing on Kansas and Missouri and Nebraska and South Dakota. On Aug. 14, the tour explored yield estimates from Minnesota, Wisconsin and Iowa. On Aug. 15, we will move into the Eastern Corn Belt -- Illinois, Indiana and Ohio -- before publishing a final look at Gro's overall national yield predictions for the 2019 corn and soybean crops on Aug. 16. Readers should note that the Gro yield visuals are continually updated, while the DTN feature articles are based on the company's yield estimate at the time the article was written. Numbers quoted in the articles may be different than those on the Gro website depending on when viewed.

To see all the tour articles and related DTN stories about the 2019 crop, visit our tour site at: https://spotlights.dtnpf.com/….

About Gro Intelligence: The New York-based company is focused on creating data analytics for the agriculture industry. Gro builds proprietary crop models that use satellite imagery, soil conditions, weather and other crop and environmental data to produce crop health and yield prediction numbers and visuals.

To learn more about Gro, go here: https://www.gro-intelligence.com/….

To read the research white paper on Gro's modeling system, go here and select to "Download the corn yield model paper": https://gro-intelligence.com/….

Emily Unglesbee can be reached at Emily.unglesbee@dtn.com

Follow her on Twitter @Emily_Unglesbee

Katie Dehlinger can be reached at Katie.dehlinger@dtn.com

Follow her on Twitter @KatieD_DTN

(AG/ES)

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