Key Takeaways

• Water timing matters as much as total water. Early-season irrigation plays a critical role in stand establishment and yield potential, especially for sugar beets and alfalfa.

• Sugar beets are most vulnerable in 2026. Limited early water can lead to major yield losses, even if more water is available later in the season.

• Corn shows yield loss quickly under deficit irrigation but offers some flexibility. Strategic in-season management can help reduce losses when water is limited.

• Dry beans align best with delayed water delivery. Later planting windows and moderate water needs make them more adaptable under current conditions.

• Alfalfa can conserve water, but the most efficient strategy depends on early irrigation. Without early-season water, expected gains from reduced irrigation may not materialize.

With canal delivery likely short in 2026, producers need realistic expectations for how each crop will perform under limited water. This article — Part three of a four-part Crop Watch series recapping the Yonts Water Conference — summarizes long-term deficit-irrigation research at the Panhandle Research, Extension and Education Center (PREEC) for corn, dry beans, sugar beets and alfalfa. Each crop responds differently, and the differences matter for 2026 planting and irrigation-scheduling decisions.

Results below are presented as relative yield — yield expressed as a percent of the maximum observed in that year’s trial — rather than absolute bushels, hundredweight, or tons. This lets us compare a dry-year and wet-year response on the same axis and focus on how much yield is lost per inch of irrigation that is not applied. 

It should be noted that although the treatments below present yield responses under some extreme water-limited conditions, the research plots were under well water which allowed flexibility in irrigation timings, especially in early crop development stages. In the case of low rainfall or canal water during early growing season, yield loss might be more significant than the numbers presented below.

Corn

Long-term corn irrigation trials at PREEC by Gary Hergert, UNL professor emeritus, tested five irrigation scenarios with 0, 5, 10, 15 and 20 inches of total seasonal irrigation water. The relative yield response under two contrasting years (wet and dry years) illustrates corn’s sensitivity to drought, so growers can get an idea of worst- and best-case scenarios. 

At 5 inches of irrigation, corn showed 40% yield loss in 2012 (dry year) and 23% yield loss in 2009 (wet year); at 10 inches of irrigation, the yield loss was 17% in 2012 and only 4% in 2009.

As mentioned earlier, the plots were under well water and there was flexibility in irrigation timing. In 2012, for example, the 5-inch treatment received about 1 inch in the first eight weeks, and the 10-inch treatment received about 1.75 inches. If a grower has no way of irrigating the crop in the first eight weeks, yield loss will very likely be higher than the presented numbers.

Dry Beans

The dry bean trials used irrigation amounts of 4, 8, 12 and 16 inches. Dry beans require less total seasonal water than corn, typically 14 to 18 inches of total crop ET. 

At four inches of irrigation, dry beans had 58% yield loss in 2007 (dry year) and 17% yield loss in 2005 (wet year). At eight inches of irrigation, dry beans had 35% yield loss in 2007 and 0% yield loss in 2005. 

Previous research (Gradiz et al., 2025) also shows that dry beans can tolerate about 25% water deficit without significant yield loss. However, beans are sensitive to excessive stress at any growth stage. Severe stress at flowering, pod fill or during the bloom window produces disproportionately large yield losses. For example, a 25% uniform deficit is manageable; a 50% deficit concentrated at flowering is not.

Sugar Beets

Sugar beet research at UNL PREEC demonstrates that sugar beets behave quite differently in wet and dry years. During wet years (2009), sugar beets were quite drought-tolerant — with only 5 inches of irrigation, they produced almost 90% of full yield. 

However, in dry years (2012), early water stress took a big toll on yield. For example, with 13.5 inches of total water, timing made a major difference. Applying 25% early and 75% late resulted in more than 80% yield loss, while applying 75% early and 25% late reduced yield loss to 60%.

Early-season stand establishment and canopy development are critical for sugar beet yield. The water outlook in 2026 makes sugar beets more vulnerable to yield loss than corn or dry beans.

Alfalfa

Alfalfa is generally drought-tolerant, as it can enter dormancy when water is limited and resume growth when moisture returns. Data from Colorado State University (CSU) trials compared four irrigation strategies: full irrigation, stop after first cutting, stop after second cutting, and stop after first cutting and resume after third cutting (Figure 4). According to the trial results, the most efficient strategy was to stop irrigation after the second cutting. This approach used about 14 inches of water and produced yields comparable to full irrigation (27 inches). However, this strategy would require early water delivery, which is unlikely for Panhandle producers in 2026.

Putting the Four Crops Side by Side

Taken together, the research suggests a clear 2026 ranking based on how well each crop’s water needs align with delayed canal delivery:

1. Sugar beets are the most exposed, because early-season demand cannot be met in the pre-canal window;
2. Alfalfa is next, because the most water-efficient strategy (stopping irrigation after the second cutting) depends on early-season water that likely won't arrive;
3. Corn is sensitive but more flexible with in-season management;
4. Dry beans align best, with a June 1 or later planting date that fits the canal delivery window. 

Part 4 of this series translates these research findings into specific agronomic decisions — plant population, nitrogen rates, planting date — plus the pre-canal water-budget worksheet and irrigation-system tips for furrow and center pivot.

About This Series

This article is part of a four-part CropWatch series recapping "Growing Crops with Limited Water in 2026," presented by Xin Qiao, UNL Biological Systems Engineering associate professor, at the Yonts Water Conference on April 8, 2026. The full series includes:

• Part 1 — How 2026 Compares: Panhandle Precipitation, Reference ET and Pre-Plant Soil Moisture Relative to 2002, 2009 and 2012
• Part 2 — What 2002, 2009 and 2012 Yields Tell Us About Drought Years
• Part 3 — How Corn, Dry Beans, Sugar Beets and Alfalfa Respond to Deficit Irrigation
• Part 4 — Managing the 2026 Season: Pre-Canal Water Budget, Crop Decisions and Irrigation System Tips

References

• Gradiz, A., X. Qiao, S. Taghvaeian, W. Liang, D. Rudnick, A. Katimbo, J. Wang, and S. Palle. 2025. Responses of dry edible bean crop growth and water productivities under different irrigation scenarios in the U.S. High Plains. Agricultural Water Management 308: 109280. https://doi.org/10.1016/j.agwat.2024.109280