September 2023

Early harvest adjustments

September is the month when the United States Department of Agriculture (USDA) brings in some new data sources to tighten up production estimates. It is the month for the first round of objective crop yield surveys for corn and soybeans where USDA representatives physically examine the crops across the nation. It is also the month when the acreage data gathered by the USDA Farm Service Agency (FSA) can be fully compared to earlier estimates. These new data sources provided some surprises for the markets and created some offsetting adjustments to the national corn and soybean production numbers.

Last year, both crops saw a reduction in planted area as planting delays showed up in force in the FSA data. This year, both crops receive a bump in planted area as more rapid planting allowed additional area to be sown. For corn, national planted area was increased by 772,000 acres to a total of 94.868 million. That brought corn planted area up by over seven percent from last year. The estimates for corn area were lowered in 19 states, held steady in 11, and increased in 18; so the increases were relatively larger than the decreases. Iowa and Illinois saw the largest declines with both states having 300,000 acre declines from the June estimates. However, that area was more than made up for in other states. Nebraska led the charge higher, with 450,000 additional corn acres. Kansas added 250,000 acres. Minnesota and Missouri each chipped in 200,000 acres. Louisiana, North Dakota, Ohio, and South Dakota increased by least 100,000 acres.

Nationally, total planted area for soybeans was increased by 95,000 acres, to 83.6 million acres. That is still 4.4% below last year’s planting. Fewer states had increased acres (eight) than decreases (14), but the sizes of the gains tipped the national total higher. North Dakota soybean plantings increased by 550,000 acres. Illinois added 350,000 acres. Iowa added 250,000 acres. Kansas increased by 200,000 acres. On the downside, Nebraska lost 250,000 acres, South Dakota dropped 200,000 acres, and Minnesota and Ohio declined by 150,000 acres each.

The next piece to the supply puzzle is the yield. The September yield estimates are a combination of the data from USDA’s objective yield survey and the simultaneous farmer yield survey. This year’s objective yield data has given both indications of good yield potential but also lost opportunities due to the drought and heat this year. Figure 1 displays the ear counts and estimated yields from the field observations for the past five years and the September update. The ear count is shown in the blue bars and uses the left axis of the graph. The 2023 ear count was the highest it has been over the five-year period, reflecting that good yield potential. However, the historical data also show that ear counts tend to decline as months pass, so we may expect that to happen again this year. The measured yield from the field observations is shown in the red dots on the graph and uses the right axis. The September 2023 observation is in the middle of the pack historically, conveying that while there were plenty of ears, those ears were not filling as well as in previous years.

Figures 1 and 2. Corn yield data and estimates

Figure 2 shows the current state and national yield estimates and how they have changed compared to last year. The national average corn yield estimate fell 1.3 bushels to 173.8 bushels per acre, but that is still slightly above last year’s yield. Iowa’s corn yield estimate was set at 200 bushels per acre, the same as last year. The heat and drier conditions across the center of the Corn Belt come out in the map. Minnesota, Wisconsin, Illinois, and Missouri are all seeing seven to ten percent declines in corn yields. With somewhat better weather conditions across the Plains, higher corn yields are estimated for the line of states from North Dakota to Texas. Putting together the acreage and yield updates, USDA found evidence to increase the corn production estimate slightly, by 23 million bushels, to 15.134 billion bushels. If this production estimate holds, that’s a gain of 1.4 billion bushels from last year.

The soybean objective yield data for this year shows some consistency with the 2021 crop, but as the historical data indicate, patterns can change. This year’s pod count is in the middle of the pack historically. Pod counts tend to increase slightly as harvest progresses. The objective yield estimate is also roughly in line with the yield estimates with the 2020-22 crops. There is no discernable pattern how that will evolve over the next couple of months. In 2020 and 2022, the objective yield estimate slowly declined. In 2021, it slowly rose.

Figures 3 and 4. Soybean yield data and estimates.

The national average soybean yield estimate came in at 50.1 bushels per acre, down 0.8 bushels from the August figure, but still above last year’s yield. The state yield losses are a bit more dispersed for soybeans, with North Dakota and Iowa joining the list with lower projected yields this year. The eastern US is seeing increased soybean potential, with record yields projected in Indiana, Ohio, New York, Kentucky, and Tennessee. Overall, national soybean production is projected at 4.146 bushels, which is 130 million bushels below last year and over 300 million bushels below the 2021 crop.

On the usage side, there were no changes for the 2023 corn crop. That allowed USDA to maintain its 2023-24 season-average price estimate at $4.90 per bushel. Soybean usage adjustments reduced domestic and international consumption. For the 2023 crop, exports were lowered by 35 million bushels, reflecting lower sales in many countries given what had been high US prices. Domestic crush dropped by 10 million bushels, so while domestic usage is still expected to grow, that growth was reduced. Despite the losses in usage, 2023-24 ending stocks are projected at 220 million bushels, down 25 million from last month and down 30 million from last year. And the 2023-24 season-average price estimate increased 20 cents to $12.90 per bushel.

Listen to the latest Market Outlook video for further insight on outlook for this month.


Chad E. Hart, extension economist, 515-294-9911,


Chad E. Hart

extension economist
Iowa State University
468E Heady Hall
View more from this author