Soil, Sky, and Soybeans: How 2025 Climate Signals Are Redrawing the Yield Map Across the Corn Belt

For soybean producers across the American Midwest, the 2025 season is shaping up to be anything but ordinary. A confluence of large-scale atmospheric patterns, anomalous soil moisture readings, and evolving La Niña conditions has set the stage for pronounced regional divergence in yield outcomes. At Martell Crop Projections, our proprietary modeling suite has been tracking these signals since late 2024, and the picture that emerges demands careful attention from every stakeholder in the soybean supply chain.

The stakes are considerable. The United States remains the world's largest soybean producer, with the Corn Belt states—Illinois, Iowa, Indiana, Minnesota, and Ohio among them—collectively accounting for the vast majority of domestic output. When climate variability disrupts even a portion of that geography, price signals ripple through domestic crush facilities, export terminals, and global end-users alike.

The Atmospheric Setup: What La Niña Means for 2025 Planting

The current weak-to-moderate La Niña episode, which meteorological agencies have tracked since the latter half of 2024, carries well-documented implications for U.S. growing conditions. Historically, La Niña phases correlate with warmer-than-average temperatures across the southern Plains and drier tendencies stretching into the western Corn Belt during the critical spring planting window.

Our analysis of sea surface temperature anomalies in the equatorial Pacific, cross-referenced with 30-year climatological baselines, suggests this pattern will persist through at least the early summer months. That timing is particularly consequential for soybeans, whose pollination and pod-fill stages—typically occurring in July and August—are highly sensitive to heat and moisture stress.

However, the La Niña signal alone does not tell the complete story. Overlaid upon it is a notably positive phase of the Pacific Decadal Oscillation (PDO), a longer-cycle ocean temperature pattern that tends to amplify drought tendencies across the northern Plains while occasionally delivering above-normal precipitation to portions of the eastern Corn Belt. This dual-oscillation environment creates a fragmented forecast landscape that blanket national projections simply cannot capture.

Soil Moisture: The Variable That Will Define Early-Season Outcomes

Perhaps no single data layer has drawn more attention from our modeling team this winter than soil moisture. Across western Iowa and much of Nebraska's eastern tier, soil profiles entered the new year in a notably depleted state following a dry autumn. Subsoil moisture reserves—which serve as a critical buffer during early-season dry spells—are running well below the five-year average in these areas.

By contrast, portions of central Illinois and much of Indiana recorded above-normal precipitation through the fall and early winter months. Field drainage in some areas has been a concern, but those saturated profiles also represent a meaningful moisture reservoir heading into the growing season.

Martell's Soil-Adjusted Yield Index (SAYI), which integrates real-time soil moisture data with historical crop response curves, currently projects a yield gap of as much as 8 to 12 bushels per acre between the western and eastern reaches of the primary soybean belt—a disparity that, if realized, would carry significant implications for basis levels and regional cash prices.

Regional Outlook: Where the Opportunities and Headwinds Lie

Western Iowa and Eastern Nebraska: These areas face the most pronounced near-term headwinds. Depleted subsoil moisture, combined with the La Niña-driven tendency toward spring dryness, creates a scenario where early-season stress could suppress stand establishment and limit yield potential from the outset. Producers in these regions should examine their crop insurance coverage thresholds carefully and consider whether forward contracting a larger-than-usual portion of anticipated production is appropriate given the elevated downside risk.

Central and Southern Illinois: The outlook here is comparatively constructive. Adequate soil moisture, relatively favorable temperature forecasts for the June planting window, and proximity to major river export infrastructure position this corridor for potentially above-trend yields—provided the mid-summer period does not bring the heat dome conditions that plagued the region in 2022. Our models assign a 38 percent probability to a July heat event of sufficient intensity to materially dent yield potential in this geography.

Minnesota and the Northern Fringe: A compressed planting window remains the perennial challenge for Minnesota soybean producers, and 2025 is unlikely to be an exception. Cooler-than-normal spring temperatures projected for the Upper Midwest suggest delayed field operations for a meaningful share of the state's acreage. That said, producers who successfully establish stands in the first two weeks of May stand to benefit from what our models flag as a favorable late-summer moisture outlook for the northern tier.

Indiana and Ohio: The eastern Corn Belt presents a nuanced picture. Excess soil moisture in some areas has created concerns about disease pressure—particularly white mold and sudden death syndrome—heading into the season. However, the same moisture profile that raises disease risk also provides resilience against mid-season drought. Net-net, these states appear positioned for near-trend yields absent an extreme summer heat event.

What Premium Pricing Opportunities Might Emerge

Beyond yield forecasting, the regional divergence our models project has meaningful implications for basis and cash price dynamics. In areas where production shortfalls materialize—particularly in the western Corn Belt—local basis levels could strengthen considerably as end-users compete for available supply. Producers in those regions who retain ownership of bushels into the late summer and fall may find the basis environment rewarding, though that strategy requires adequate storage capacity and tolerance for price risk.

In higher-production areas of central Illinois and Indiana, the opposite dynamic may apply. Abundant local supply could pressure basis levels, making early forward sales or the use of futures-based pricing tools more attractive for locking in profitable margins.

"Regional basis behavior in a divergent yield environment can be as important as the futures price itself," noted one commodity risk consultant who works closely with Corn Belt producers. "Growers who understand their local supply-demand picture are in a fundamentally stronger negotiating position."

Translating Forecasts Into Action

The practical takeaway from Martell's 2025 soybean analysis is straightforward: this is not a season for one-size-fits-all decision-making. Producers should be actively stress-testing their marketing plans against both the upside and downside scenarios our models have identified for their specific geography.

For those in moisture-stressed regions, prioritizing drought-tolerant variety selection and reviewing irrigation infrastructure capacity—where applicable—represents a logical first line of defense. For producers in the eastern belt, scouting protocols for fungal diseases should be elevated given the soil moisture backdrop.

At Martell Crop Projections, we will continue updating our regional soybean yield models on a biweekly basis through the growing season, incorporating new soil moisture readings, weather station data, and satellite-derived vegetation indices. The 2025 season will reward those who remain engaged with the evolving data—and penalize those who rely on last year's assumptions.