Regenerative agriculture improves soil health by producing more nutritious crops

  • Researchers compare the nutritional content of food crops grown using conventional and regenerative agricultural practices – those that build soil through the use of cover crops, diverse crop rotation and minimal tillage
  • Food grown on regenerative farms contains on average more magnesium, calcium, potassium and zinc; more vitamins (including B1, B12, C, E and K) and more phytochemicals.
  • “Above all, soil health appears to affect phytochemical levels in crops,” the authors write, “showing that regenerative farming systems can increase nutrient levels of compounds known to reduce the risk of various chronic diseases.”
  • Regenerative farms also had generally healthier soils with more carbon.

Plants are made up of sunlight, water and soil. And, as it turns out, what crops “eat” can affect the nutrients in our own dishes.

A recent study published in the journal PeerJcompares the nutritional content of food crops grown using conventional versus regenerative farming practices – those that build soil through the use of cover crops, diverse crop rotation and minimal tillage.

“It was very difficult to find studies that explicitly looked at soil health and how it affects food,” lead author David Montgomery, a professor of Earth and space science at the University of Washington, told Mongabay. “We did the experiment we wanted to be there.”

The researchers turned to a network of farmers they knew had successfully restored soil fertility on their land using regenerative farming practices. Ten regenerative farms agreed to grow 1 acre (0.4 hectares) each of peas, sorghum, corn or soybeans to compare the results with the same crop grown on a neighboring conventional farm.

The dark colored soil on the right has been cultivated using regenerative practices such as uncultivated and with cover crops for decades, while the pale soil on the left is from a cultivated field without cover crops on the other side of the road. Darker soil is healthier, with more organic matter to retain moisture. Photo by Dale Strickler.

“The goal was to try to get some direct comparisons where you controlled key variables: the harvest is the same, the climate is the same, the weather is the same because they are right next to each other, the soil is the same. the same for the type of soil, but it has been grown in a completely different way for at least five years, ”said Montgomery.

Food grown on regenerative farms was found to contain, on average, more magnesium, calcium, potassium and zinc; more vitamins (including B1, B12, C, E and K) and more phytochemicals. They also have fewer elements that can be harmful to human health, including sodium, cadmium and nickel.

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

“Above all, soil health appears to affect phytochemical levels in crops,” the authors write, “showing that regenerative farming systems can increase nutrient levels of compounds known to reduce the risk of various chronic diseases.”

They also found that beef and pork raised on one of the regenerative farms had higher levels of omega-3 fats and a healthier ratio of omega-6 to omega-3 fats than meat from local supermarkets. .

Montgomery and co-author Anne Bickle further discuss the relationship between soil, crop health and human health in their forthcoming book, What your food eatscomes out in June.

We thought about writing the word “diet” in large volumes and asking, “What does food eat?” “If you think of culture as a diet, that’s really what you feed the soil with, how you fertilize, how you treat the land, and so on,” Bikle said.

Regenerative farms generally had healthier soils with more carbon, measured by their organic matter and a test that determined the amount of nutrients in the soil available to soil microbes.

A healthy soil ecosystem is full of a variety of microbes. All plants, including crops, have a microbiome (an internal community of fungi and bacteria similar to the human gut microbiome) extracted mainly from the soil. A diverse range of fungi and bacteria helps to gather and stimulate beneficial compounds, such as trace elements and phytochemicals related to human health.

Think of the microbiome as a football team: a plant grown in solid soil, has a huge recruitment set and can play with a complete first series list and many backups. A plant grown in poor soil can be rented only in the neighborhood and can only be with a bunch of goalkeepers – it can work, but not optimally and probably does not attract sponsorships or recruit the best players for next season.

“Intuitively, we can have a good feeling that improving soil health will improve the nutrient density of the foods you eat, but there hasn’t been that much research,” said Fred Provenza, an honorary professor at Utah State University who is not participated in the study, Mongabay said. “So it’s very nice to see studies and they really looked at a wide range of different plant species across the country. I really applaud the work they have done. “

Regenerative agricultural practices – such as planting a variety of crops, rotating those crops and using unprocessed methods – promote diverse and healthy soil microbiomes.

Tillage, a common practice in both conventional and large-scale organic farming, breaks down soil particles, making soil organic matter available for microbial consumption, which in turn releases a lot of fertility. The problem with tillage, soil expert Dale Strickler said in an interview with Mongabay in 2021, is that it ultimately degrades the soil.

“It simply came to our notice then [of organic matter] and then you’re much worse than ever, “Strickler said. “And now your soil is not absorbing rainfall, the roots cannot enter because there is no structure, no oxygen movement, no gas exchange and you are stuck. You have dead ground. “

One of the research sites, Brown’s Regenerative Ranch, covers 5,000 acres in North Dakota and has been practicing uncultivated farming since 1993, serving as a model for other farms in the region. Here, grazing animals are an important part of the system, moving through the landscape to help regenerate soils. Photo by Anne Bickle.

In total, the study examined eight pairs of regenerative and conventional farms in the United States, North Carolina, Pennsylvania, Ohio, Iowa, Tennessee, Kansas, North Dakota and Montana. One thing that stands out, Bikle said, is the difference in soil between all farms. Although regenerative farms had healthier soils, the difference in soil between sites varied greatly in remote locations.

The authors say they hope this type of work will continue on a larger scale to capture even more of the variations in soil between regions and agricultural techniques.

“The biggest criticism I would have of this study is the small size of the sample – that’s why the title of the article includes the word ‘advance,'” Montgomery said. “I would like to see many more studies begin to quantify: How do differences in soil health affect the quality of crops that come from this land?”

Provenza said he would like to see a study looking at comparisons of tastes between agricultural techniques, as phytochemical richness can affect food tastes and levels of phytochemicals have declined in conventional farming practices.

“Nowadays you go to the store and fruits and vegetables can look great, but as we all know, they have absolutely no taste,” said Provenza. “And this reflects the huge decline in phytochemical wealth from conventional agricultural practices that are killing the soil.”

“It may be that one of our biggest levers in the fight against the modern epidemic of public health from chronic diseases is to rethink our diet,” added Montgomery, “and not only what we eat, but how we grow it.”

Quote:

Montgomery, DR, Bikle, A., Archuleta, R., Brown, P., & Jordan, J. (2022). Soil health and nutrient density: Preliminary comparison of regenerative and conventional agriculture. PeerJ, 10, e12848. doi: 10.7717 / peerj.12848

Banner image from corn by Mooney77 via Flickr (CC BY-NC-ND 2.0).

Liz Kimbrow is a full-time writer for Mongabay. Find her on Twitter @lizkimbrough_

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