The many benefits of a diverse crop rotation

Posted on
October 27, 2020
Buffy Uglow    buffy_uglow@rockriverlab.com

By: Dustin Sawyer, laboratory director and soil scientist

Diversity keeps life interesting, and we may be able to draw on an important idea in psychology to help improve our agriculture. There’s a popular idea in psychology that suggests habitual behavior can limit our ability to think creatively or cause us to overlook opportunities. Think about your daily routine. Is there a part of the day that just seems to run on autopilot? Perhaps it’s the morning commute, or checking emails, but there always seems to be some time in the day where we can stop and think “I don’t remember any of the last ten minutes.” That’s our brains running on autopilot. If we think back and can’t remember the details of the past ten minutes, how can we be sure that we didn’t miss an opportunity? Maybe there was a chance to rethink the task we were performing, or maybe there was a window of opportunity that could have changed the trajectory of life.

How does the psychological community suggest we combat autopilot? One simple idea: add diversity to our routine. Adding some diversity to our routines is a really simple way to train our brains to be more alert to the environment. This can be as simple choices such as taking a different route to work every now and again, answering emails in a random order, or switching up our grocery store periodically. Ultimately, adding diversity improves our brain’s adaptivity and an adaptive brain can be a more creative brain, making us better at problem-solving, spotting new opportunities, and hopefully living longer, fuller lives.

Though it may not be immediately obvious, this idea from the world of psychology ties beautifully into agriculture. It comes down to the fundamental idea that diversity leads to flexibility. Just as this idea holds within the brain, it holds within any natural system. Nature thrives on diversity. Try to picture the nitrogen cycle, or quick look it up if needed. The complexity of the system is instantly apparent, and this is only one of the soil systems vital to crop production. Add in other nutrient cycles, the metabolic processes of plants, the greater pest ecosystem, etc… and the important role that diversity plays in a healthy system suddenly becomes very clear.

We’re in an interesting time with regard to cropping diversity. Consumer and farming communities both have a growing interest in the idea of soil health and sustainable agriculture. The idea of healthy eating extends beyond the idea of whether food is healthy for the person and now asks whether the food system is healthy for the ecosystem. Of course, the idea of diversity in cropping systems is nothing new. Textbooks are replete with stories of the native Americans practiced companion cropping with the three sisters: corn, beans, and squash. The industrial revolution and subsequent mechanization of agriculture swung the mentality of agriculture toward the monocultural, single-task systems that machines are really good at, but public opinion is beginning to swing the needle back the other way. Tied in with this is the resurgent concept of soil health. While the idea of measuring soil health seems new and novel, the concept is as old as agriculture itself and can be embodied by one simple word: diversity.

Soil health measures are getting better every day, and many of them focus on trying to quantify the diversity of life in the soil. Carbon dioxide burst testing attempts to quantify the microbial mass of the soil, the slake test is an assessment of soil aggregate stability, and nitrogen mineralization rates give insight into how active the soil microbes are. The diversity of the soil microbial community has an impact on all of these, and many other, soil health measures. Soil health researchers are even looking at DNA sequencing of soil to determine the soil’s diversity.

Life in all of its natural forms needs diversity. Diversity provides the checks and balances needed to keep any one species from dominating the landscape and subsequently depleting the very resources that keep it alive. Let’s look at the crop from the perspective of a pest for a moment. Whether the pest is an insect, bacteria, or a virus, there’s one thing that pests love and it isn’t diversity. Pests love predictability.

Remember: diversity leads to flexibility. It helps prevent the mind from getting stuck in a rut, and it builds a better agricultural system that is more resistant to environmental stresses. There are readily available and relatively easy ways to add it in both places. In fact, diversity can be added to both by simply planting a cover crop while running the planter in a new pattern.

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