Beyond No-Till: Why Crop Rotations Matter More Than You Think
- the Growing Resilience Team
- 4 hours ago
- 3 min read
By the Growing Resilience Team
For decades, no-till has been hailed as a cornerstone of regenerative agriculture—an essential practice to protect soil while still producing food, feed, fuel, and fiber. However, a groundbreaking thesis by soil scientist Natalie Sturm, conducted at the Dakota Lakes Research Farm in central South Dakota, shows that no-till is only part of the equation.
It’s not just about reducing disturbance. It’s about what you grow—and how you grow it.
Natalie’s study examined nearly 30 years of data (1991–2021) across both irrigated and dryland cropping systems, all under long-term no-till. Her findings are clear: how you design your crop rotation—particularly how much residue you return to the soil and how diverse your system is—has an impact on soil health and grain yields.
Key Finding #1: Residue and Diversity Are Game Changers for Soil Health
Even under the same no-till management, rotations that included a greater proportion of crops with high carbon-to-nitrogen ratio residues (like corn, sorghum, and winter wheat) and greater diversity (a mix of grasses, broadleaf crops, and cool/warm seasons) showed:
Higher soil organic matter (SOM),
Better soil structure, measured by mean aggregate size,
Stronger fungal communities and higher microbial diversity,
Lower surface runoff and better infiltration.
For example, the corn-corn-soy-winter wheat/cover-soy rotation (C-C-S-W-S)—which included about 60% high-carbon crops and high diversity—produced better soil fungal populations and greater aggregate size than simpler systems like corn-soy (C-S), which had only 50% high-carbon crops and low diversity.
Key Finding #2: You Don’t Have to Sacrifice Yield
Some worry that adding more crops—or stepping away from simplified rotations—will reduce grain yields. But at Dakota Lakes, the opposite proved true.
The first-year irrigated corn in C-C-S-W-S averaged 212.2 bu/ac, outperforming both the corn-soy rotation (198.2 bu/ac) and continuous corn (183.5 bu/ac). It should be noted that second-year corn however, yielded 191.4 bu/ac.
In dryland systems, wheat-corn-broadleaf and wheat-wheat-sorghum-corn-broadleaf maintained or slightly improved wheat yields compared to a rotation with a broadleaf crop every other year while also building better soil—especially at deeper layers.
Rotations with higher proportions of high-carbon crops consistently showed more yield stability over time, even in tougher years.
In fact, the simpler corn-soy system only outperformed C-C-S-W-S in 4 of the 17 years studied.
Key Finding #3: Soil Health Is More Than Just Going No-Till
Natalie’s work also revealed that diversity alone isn’t enough if it doesn’t come with residue. High diversity with low biomass can leave soils biologically rich but chemically and physically degraded. Conversely, continuous corn, with 100% residue, built SOC but lacked the biological diversity needed for yield gains.
The sweet spot? Rotations that balance diversity and residue—typically with 60–80% high-carbon crops and 2 or more functional crop types.
Why This Matters
Too often, no-till is promoted as a one-size-fits-all solution. However, as Natalie’s thesis demonstrates, no-till without thoughtful crop rotation is like building a house without a foundation. It helps, but it doesn’t finish the job.
To truly regenerate soil, support yields, and prepare for weather fluctuations, crop rotation must be front and center in soil health conversations.
Natalie’s full thesis, “It’s Not Just No-Till: Crop Rotations Are Key to Improving Soil Quality and Grain Yields at Dakota Lakes Research Farm,” is now available [here]
Natalie’s video on this subject is at this link: https://dakotalakes.com/its-not-just-no-till-with-natalie-sturm/
Dakota Lakes 2020 Field Day is also an excellent Resource. The full playlist (20 videos) can be found [here]
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