Martell: Heat Wave to Build Across Corn Belt This Week

June 25, 2012 09:13 AM

The following content was provided by meteorologist Gail Martell of

Heat Wave This Week in Corn Belt

Hot air is projected to expand across the Great Plains into the Midwest and Mid South on Wednesday and Thursday introducing heat wave conditions to corn and soybeans already plagued by drought.

updated 5 day

Crops have deteriorated east of the Mississippi River from oppressive heat and dryness. Eastern Midwest temperatures last week continued 4-6 F above normal, despite a forecast for cooler conditions.

June rainfall has increased in a swath from Kansas northeastward affecting eastern Nebraska, western Iowa, Minnesota and northern Wisconsin. This is where corn and soybeans are hanging on, getting enough rainfall to prevent strong deterioration.


Corn silking and pollination is advancing in the earliest planted fields. This is a yield-sensitive stage of development requiring .20 inch of moisture, per day, for successful kernel development. There is not enough stored ground moisture to supply increasing corn needs on the majority of Midwest farms.

The forecast this week is hot and dry from a building ridge of high pressure in the heartland. Peoria, Illinois maximum temperatures are predicted to be 79 F today, 82 F tomorrow and 92 F on Wednesday. Thursday and Friday would be 100 F and 95 F, respectively. Not too much rain is expected in the 5-day forecast, just variable and scattered showers in a band from Nebraska, Iowa and northern parts of Illinois and Indiana and Ohio.

Excessive Wetness in Canadian Prairies Threatens Crop Quality

Canada prairie crops conditions are becoming too wet in a cool and rainy summer causing worries over disease and weed control. It is a odd contrast with the United States heat and dryness in the heartland and a classic La Nina weather pattern, though ENSO-neutral conditions are said to exist.

june extreme

The Saskatchewan June 21 newsletter claimed some crops had flooded from excessively wet conditions from 4 inches of rainfall in the week. Topsoil moisture was rated 48% surplus and 52% adequate. Most crops were in good to fair condition though pest control applications were being hindered by extremely wet fields. Coolness was delaying crop development, though, due to early seeding, spring grains were not significantly late.

Manitoba producers were applying fungicides and herbicides to combat disease and weeds from very wet conditions. The risk level for fusarium head blight was "high to extreme" in winter cereal crops the week ending June 18. Weeds were a challenge in spring wheat and barley, while producers scouted fields for disease pressure.

Alberta crops on June 12 (the most recent report) were considered mostly good to excellent. Small grains and canola has received ample, but not extremely heavy rainfall.

Brazil Winter Corn Boosted by Heavy Rain

Parana Brazil’s largest corn state has received beneficial heavy rainfall that boosts yield potential in winter corn. The summer corn harvest was damaged by extremely dry conditions, December-February. Though fall conditions were very dry for winter-corn planting, rainfall began improving in May and June.

heavy brazil

Parana received above- normal rainfall in the recent 7-8 weeks, boosting crop potential. Neighboring winter-corn states Mato Grosso do Sul and Sao Paulo also have received heavy, beneficial rainfall. Mato Grosso , Brazil’s leading soybean state, is expecting corn production to be over-the-top. Winter corn plantings, sown after the soybean harvest, were reportedly 38% higher than last season.

The USDA projects Brazil 2011-12 corn production at a record 69 million metric tons generating exports of 12 million metric tons. In early June, delegates from China were working with Brazil on final paperwork that would clear the way for corn trade between the two countries, according to Brazil's head of foreign affairs.

Argentina Intense Dry Spell Slows Wheat Planting

Winter wheat planting reached 25% complete by mid June , but germination has been slowed by drying topsoil conditions. Night frosts have also been a hindrance to wheat development in Buenos Aires, the leading producing area where 55% of the national harvest is produced. Deep-layer soil moisture was still adequate based on a soil moisture map from Argentina's weather service. May weather was wet in Buenos Aires. However, the weather suddenly turned dry in the past month with only 12 millimeters of rain compared to 30 mm normally. The new forecast is not hopeful for rain either in the winter wheat belt.

argentina emerging

Perhaps a lingering La Nina signal is influencing the weather, causing dryness that hampers wheat sowing. Argentina weather is highly sensitive to the ENSO signal, turning in the grain belt when La Nina is in effect.

The USDA projects Argentina wheat production at 12 million metric tons in the 2012-13 growing season. Production of winter wheat has been declining steadily over the past decade, at soybean production has expanded. Argentina soybean plantings have increased 75% from 2000 to 2010, while the winter wheat area has shrunk 57% in the same period.




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