Broadleaf Considerations for West River South Dakota Cropping Systems

Mar 31, 2025

By Clarence Winter

Selecting the right crop rotation is crucial for the success of any farming operation, especially in areas like western South Dakota, where water use efficiency is critical. The rise of no-till agriculture has expanded the range of crops that can be grown in these regions due to better water retention in soils. However, determining which crops are best suited to a farm's unique goals remains a complex decision, particularly when it comes to choosing broadleaf crops. This article aims to explore key factors to consider in selecting broadleaf crops and what some farmers in the region are already planting.

Planning Crop Rotation

A well-planned crop rotation should focus on three main principles: proper intensity, adequate variety, and stable profitability. Intensity refers to how efficiently crops utilize stored soil water, which is especially important in areas with limited moisture, like Western South Dakota. With a shorter growing season, farmers must approach crop rotations with these environmental challenges in mind. Adequate variety is achieved by including different types of crops to disrupt weed and pest cycles, while stable profitability ensures that the farm remains economically viable for current and future generations.

In no-till farming systems, maintaining adequate residue in the field is essential for building organic matter and conserving soil. Both cool and warm-season grass crops, such as wheat and corn, are ideal in this context, because they produce large amounts of residue. These crops also align well with the natural prairie ecosystem of Western South Dakota, where grasslands once dominated the landscape. However, broadleaf crops play an important role in a farm's rotation and improving profitability. Traditional broadleaf options that work well with wheat and corn include peas (cool season), soybeans (warm season), and sunflowers (warm season).

    Traditional Broadleaf Crops

    Sunflowers have been a staple crop in South Dakota for decades, with the state ranking second in sunflower production in the U.S. In 2023, South Dakota produced over 817 million pounds of sunflowers (Sandbakken, 2023). However, growing sunflowers comes with its own set of challenges, including pest and pathogen issues, like the red sunflower seed weevil and Phomopsis stem canker (Varenhorst 2023; Bush et al. 2019). These problems have been exacerbated by the increase in sunflower acreage and the development of pyrethroid insecticide resistance. In addition to pest pressures, sunflower markets have faced a downturn since 2022, prompting farmers to consider alternative broadleaf crops.

    Warm-season broadleaf crops, such as sunflowers, also present challenges related to soil health. After harvest, the short time window to establish cover crops or try relay cropping makes it difficult to prevent soil erosion, especially in dry conditions. Moreover, sunflowers are heavy users of both water and nitrogen, which can strain the subsequent crop. Broadleaf crops generally produce less residue compared to grasses, which can undermine efforts to build organic matter and retain soil moisture. To address these issues, farmers are encouraged to rotate different types of broadleaf crops (both cool-season and warm-season) year-to-year or grow them less frequently (once every four or five years), to mitigate their negative effects.

    Alternative Broadleaf Crops

    Fortunately, there are alternative broadleaf crops with strong market potential and a better ecological fit for Western South Dakota. One such crop is canola, a cool-season broadleaf that not only has a robust market but also offers environmental benefits, such as improved residue levels. In 2024, canola grown near Martin, South Dakota, yielded 1,500 pounds per acre (30 bushels/acre) and produced 2,500 to 3,500 pounds of dry residue per acre (Figure 1 and Figure 2). This level of residue is significantly higher than that of other broadleaf crops, and with residue standing 10 to 14 inches tall, canola fields are better at capturing snowfall during the fall and winter. This "snow catch" ability can be particularly beneficial in areas where water conservation is crucial.

    Other promising crops are camelina or flax, brassica oil crops similar to canola. These crops can be drought-tolerant, have short growing seasons, and are genetically resistant to pests and herbicides. These characteristics make them a strong fit for crop rotations in western South Dakota, where environmental conditions can be harsh. These three alternative broadleaf crops still have limitations however, including the potential for shatter losses in high heat and drought conditions, so careful consideration is needed when making these decisions.

    In Summary

    In conclusion, choosing the right crop rotation is essential to successful farming, especially in regions like Western South Dakota. Farmers must prioritize water conservation, soil health, and organic matter build up in their rotations. When selecting broadleaf crops, it’s important to focus on intensity (water use), variety (at least three crop types), and profitability. Exploring alternative broadleaf crops, like canola, camelina, or flax, can help meet these goals, ensuring long-term sustainability for farms in the region.

    Source : sdstate.edu