Farms that follow soil-friendly practices grow healthier food, study finds

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February 24, 2022

Everyone knows that eating fruits and vegetables is good for your health. But today, stores offer a dizzying array of options: organic, conventional, CSA, locally grown. Which are the best for your health?

A new studypublished in January in the journal PeerJ, examines how regenerative farming practices — soil-building techniques that minimize tillage, use cover crops, and plant diverse crops — affect the nutritional content of foods.

Results from the preliminary experiment, which included 10 farms across the United States, show that crops from farms following soil-friendly practices for at least five years had a healthier nutrient profile than the same crops grown on the farms. neighboring conventional ones. The results showed an increase in certain minerals, vitamins and phytochemicals beneficial to human health.

“We were unable to find any studies directly related to how soil health affects what enters crops,” the lead author said. David Montgomery, UW Professor of Earth and Space Sciences. “So we had the experience that we wanted to be there.”

Montgomery devised the study while researching his next book, “What your food ate”, to be published in June. His wife, Anne Bikleis a biologist and co-author of the study and the forthcoming book.

The authors collaborated with farmers using regenerative farming practices to conduct an experiment. All participating farms, primarily in the Midwest and Eastern United States, agreed to grow one acre of a test crop – peas, sorghum, corn or soybeans – for comparison with the same crop grown in a nearby farm using conventional agriculture. Co-author Ray Archuletaa retired U.S. Department of Agriculture soil conservation scientist, visited all farms and sampled their soil in the summer of 2019. Farmers then sent in samples of their crops for analysis.

The study looked at farms across the United States doing regenerative agriculture, which uses soil-strengthening practices. In eight of the farms (farms 2 to 9), the farmers planted the same crop as their neighbor to allow a direct comparison of the soil and the resulting food.Montgomery et al./PeerJ

“The goal was to try to get direct comparisons, where you controlled for the key variables: the crop is the same, the climate is the same, the weather is the same because they’re right next to each other, the soil is the same in terms of soil type, but it was grown very differently for at least five years,” Montgomery said.

Study sites included co-author Paul Brown’s farm and ranch. Brown had met the UW researcher during Montgomery’s work for the 2017 book, “Growing a Revolution,” which visited regenerative farms in the United States and abroad, including Brown’s Ranch in North Dakota. North.

The results of the new study showed that farms practicing regenerative agriculture had healthier soils, as measured by its organic matter, or carbon, content and by a standard test.

“What we’re seeing is that the regeneratively farmed soils had twice the carbon in their topsoil and a three-fold increase in their soil health score,” Montgomery said.

Culture samples were analyzed in laboratories at UW, Oregon State University and Iowa State University.

Foods grown using regenerative practices contained, on average, more magnesium, calcium, potassium, and zinc; more vitamins, including B1, B12, C, E, and K; and more phytochemicals, compounds that aren’t usually tracked for the diet, but have been shown to reduce inflammation and improve human health. Crops grown on regenerative farms also contained fewer elements generally detrimental to human health, including sodium, cadmium and nickel, compared to their conventionally grown neighbors.

“Overall, we’ve found that these regenerative practices infuse our cultures with more anti-inflammatory compounds and antioxidants,” Montgomery said.

close up of a hand holding two soil samples

A person holds soil from a regenerative farm (blacker soil on the left) for comparison with soil from a nearby conventional farm (right).David Montgomery/University of Washington

Organic farms avoid chemical pesticides, but they can vary in their other farming practices, such as whether they have a diversity of crops or whether they till the soil to control weeds. Results of a previous exam studypublished by Montgomery and Biklé in the fall, show that organic crops also generally have higher levels of beneficial phytochemicals than crops grown on conventional farms.

Researchers believe the key lies in soil biology – the microbes and fungi that are part of the soil ecosystem – as these organisms help directly and indirectly boost beneficial compounds in crops.

“Soil biology was really the part that was overlooked when moving to chemical-intensive agriculture,” Montgomery said. “Perhaps one of our biggest levers in trying to tackle the modern public health epidemic of chronic disease is to rethink our diets, and not just what we eat, but how we grow it.”

The study also included cabbage grown on a no-till farm in California and a single wheat farm in northern Oregon that compared its own conventional and regenerative farming practices and provided both samples. The study included meat from a single producer, Brown’s Ranch; beef and pork raised on regenerative agriculture feeds were higher in omega-3 fatty acids than meat from a conventional feedlot.

“The biggest criticism I would have of this study is the small sample size – which is why the title of the article includes the word ‘preliminary,'” Montgomery said. “I would like to see a lot more studies start quantifying: how do differences in soil health affect the quality of crops that come from these lands?”

The other co-author is Jazmin Jordan of Brown’s Ranch. The study was funded by the Dillon Family Foundation.

For more information, contact Montgomery at [email protected]

Tag(s): College of the Environment • David Montgomery • Department of Earth and Space Sciences

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