The first full day of fall brought a mixed bag to ag markets. While soymeal slipped, most grain futures posted modest gains, helped by steady harvest progress, strong export sales, and rising global energy prices.

Corn and wheat took the lead, while soybeans ended slightly higher. Livestock feed markets and global policy developments continue to cast influence, especially as traders react to Argentina's surprise removal of grain export taxes.

Corn prices closed higher, with December contracts gaining 5 cents to settle at $4.26. Support came from the announcement of a second consecutive day of corn sales to Mexico, totaling over 123,000 metric tons for the 2025-26 and 2026-27 marketing years.

Despite better domestic production forecasts in Mexico, the USDA's Foreign Agricultural Service expects the country's corn imports to remain strong, citing growing feed and processing demand. Early U.S. export activity is already nearing 2.4 million bushels this marketing year.

November soybean futures traded choppily, closing at $10.12, up a penny from the open. While soy oil prices climbed more than a third of a point, soymeal fell 1%, finishing at $275.10.

The pressure on soymeal stems from Argentina's temporary removal of export taxes, making its products more competitive on the global market. Previously, Argentina taxed soymeal at 24.5%, soybeans at 25%, corn at 9.5%, and soy oil at 24.5%. This shift could impact global demand dynamics, especially for U.S. soy products.

Argentina's soymeal exports - valued at nearly $8 billion - lead its ag trade portfolio, followed by corn ($6.5B) and soy oil ($4.2B). July 2025 alone saw a year-over-year export increase of $11.4 billion, with China and the U.S. as top buyers.

Wheat markets bounced back from recent weakness, with Chicago December futures rising to $5.20, a full 9-cent gain. Kansas City wheat added 10 cents to close at $5.11, while spring wheat contracts advanced 3-4 cents across the board.

With no major global production threats, gains likely stemmed from technical buying and spillover strength in corn and energy markets.

Crude oil and diesel prices rose nearly 2%, closing at $63.52 and $2.33, respectively. Natural gas also climbed to $2.86. The jump followed Russia's fuel export ban, ongoing drone attacks on production infrastructure, and tighter global inventories.

The U.S. Energy Information Administration is expected to release updated domestic petroleum data Wednesday, which could further influence fertilizer and diesel input costs for U.S. farmers during harvest.

While grains firmed up, equities struggled. The Dow closed at 46,600 (down 0.25%), the S&P dropped over 0.5% to 6,718, and the Nasdaq lost 0.75%, ending at 24,836.

Federal Reserve Chair Jerome Powell signaled ongoing economic caution, noting recent interest rate adjustments aim to balance inflation risks and labor market weakness. The Fed's preferred inflation metric, the core PCE index, is expected at 2.9%, still above its 2% target.

Friday's Consumer Price Index report may influence future rate moves, with ag markets likely to watch implications for commodity financing and input costs.