Extension Communications 3614 Administrative Services Building Ames, Iowa 50011-3614 (515) 294-9915

8/19/03

FOR IMMEDIATE RELEASE

Contacts:
Robert Wisner, Ag Economics, (515) 294-6310, rwwisner@iastate.edu
Jean McGuire, Continuing Education and Communication Services, (515) 294-7033, jmcguire@iastate.edu

Deteriorating Crop Conditions Tighten Corn and Soybean Supplies

Ames, Iowa -- The USDA's Weekly Weather and Crop Bulletin showed a substantial reduction in both corn and soybean crop conditions west of the Mississippi River for the week ending Aug. 17. While there was a modest improvement in reported crop conditions in Indiana, Ohio and Kentucky, Robert Wisner ISU Extension economist, said the deterioration farther west more than offset the improvement in these states. Daytime temperatures in the 90-100 degree range over most of the area, along with 100 degree plus temperatures in Kansas and Missouri, lack of rain and limited subsoil moisture caused the deteriorating conditions.

For the 18 corn- and soybean-producing states as a group, the corn crop declined from 65% rated good to excellent the previous week to 60% good to excellent on August 17. Comparable figures for soybeans were 62% and 56% respectively. The maps below show the percentages of corn and soybeans rated good to excellent in the Weekly Weather and Crop Bulletin for 8/18/03 and the changes from the previous week. Declines were especially large in Iowa and Minnesota, two states that had generally very good crop conditions as recently as two weeks ago.

Wisner said impacts on yield potential are a bit uncertain, but stress is evident from firing of lower leaves on the plants. In some cases, corn plants on lighter soils have died prematurely and yields will be quite low in those fields. In Iowa, these situations often are in small areas, in river and creek bottomland.

Deterioration in soybean crop conditions reflected both the hot, dry weather and numerous reports of soybean aphid infestations in the western Corn Belt. Much spraying is being done for aphids. August typically is the most critical month for soybean yields in the Midwest, from a weather standpoint. This is the time when the plant is completing pod formation and seed filling. August rains, or lack of rain, can have considerable impact on yields, test weights and oil content of the beans. Sharply lower soybean crop condition ratings for the week ending August 17, 2003 in Iowa, Minnesota, Wisconsin, South Dakota, Nebraska and Kansas are indicators of continuing deterioration of yield prospects from very good conditions earlier. If widespread rain is not received soon, the ISU economist said significant strength in old and new-crop soybean prices is possible, along with modest strength in corn prices.

For corn, Wisner said a yield-forecasting model that relies heavily on the crop condition ratings showed a potential U.S. average yield of 137.7 bushels per acre with the August 17 ratings, down from a forecast of 140 bushels per acre the previous week and the USDA, NASS August 12 forecast of 139.9 bushels per acre. He added that a 137.7 bushel per acre U.S. average corn yield would produce about 9.9 billion bushels of corn, equaling expected total used for the year ahead. With that combination, market analysts would expect U.S. August 31, 2004 corn carryover stocks to remain approximately constant at this year's relatively low level.

For soybeans, a 1.0 to 1.5 bushel per acre loss of yield from USDA's August 12 yield forecast of 39.4 bushel per acre would create the potential for U.S. soybean carryover stocks to decline again in 2004, from already very low levels this year. Last year's U.S. average soybean yield was an estimated 37.8 bushels per acre. Wisner said August 31, 2003 U.S. soybean carryover stocks are expected to be about a 2.6 weeks' supply at the annual average rate of use, the lowest as a percent of use since 1972-73. At the same time, however, South American stocks are expected to be record large and will somewhat temper upward potential on soybean prices.

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Editors: Two color photos, suitable for publication, are available at right. Click on each thumbnail photo to go to the fullsized photo. The top picture's fullsize photo is 216K and the bottom picture's fullsize photo is 228K. Caption: Corn Crop Percent Good to Excellent, 8/17/03 & Change vs. 8/10/03
Caption: Soybean Crop Percent Good to Excellent, 8/17/03 & Change vs. 8/10/03

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