The research results have shown that regenerative farming practices improve soil health and the nutritional profile of crops and livestock meat.
Reports concerning the decline in nutrients from agricultural commodities in recent decades are not rare. Most of the time, this decline is attributed to crop breeding for yield and related attributes. However, a growing body of research is demonstrating that fertiliser management and microbial life in the soil fundamentally affect plant nutrient uptake. This research shows that conventional agricultural practices of intensive tillage, mineral nitrogen fertilisation and pesticide application not only lead to a disruption of the symbiosis between crops and soil life, but also to a lower nutritional value of the crops grown.
This study* included 8 regenerative and 8 neighbouring conventional farms. The farms were located throughout the USA, namely in the states of North Carolina, Pennsylvania, Ohio, Iowa, Tennessee, Kansas, North Dakota and Montana. The selected fields of the neighbouring farms, which grew the same varieties of the selected crops (peas, sorghum, corn or soybeans), were identical in soil type. The selected regenerative farms utilised holistic management, which combined minimum tillage, maximum use of cover crop and diverse crop rotations, and had been farmed in that way for 5 to 10 years at the time of the survey.
From the nutritional point of view, vitamins (B, C, E and K), minerals (Al, Ca, Cu, Fe, K, Mg, Mn, Na, P and Zn) and phytochemicals (total phenolics, phytosterols and carotenoids) were monitored and measured. For the soil samples, the authors assessed the soil organic matter content and the so-called soil health score using the Haney test (Haney et al., 2018), which determines microbial respiration over 24 hours, water-soluble organic carbon, organic nitrogen, nitrate, ammonia and phosphate. In addition, a special weak organic acid solution, mimicking the action of root exudates, was used to evaluate the amount of dissolved elements Al, Fe, Ca, P and K as well as nitrate, ammonia and phosphate. These results assess soil microorganism activity and the amount of food readily available to them. They also reveal the amount of nitrogen, phosphorus and potassium available to plants and provide an indication of the state of the soil in relation to the cycling of other nutrients.
In addition to this main experiment, the authors also examined (also using the Haney test) the soil health value and nutrient content of cabbage grown on a regenerative vegetable farm in California with the same cabbage variety grown on a nearby organic farm. Another side trial monitored the nutrient content of wheat directly sown into a cover crop stand compared to wheat sown into a herbicide-treated stand after a pre-crop. As a final side trial, the authors compared the fatty acid profile of beef and pork raised on a regenerative farm with meat from a regional organic brand and meat from conventionally raised animals.
Without exception, the soil on the regenerative farms had more soil organic matter and higher soil health scores according to the Haney test**. Specifically, the soil organic matter content of the regenerative fields ranged from 3-12% (mean = 6.3%), while the conventionally farmed fields had soil organic matter of 2-5% with a mean of 3.5%. Haney scores for regenerative farms ranged from 11 to 30 (mean = 20) and for conventional farms from 3 to 14 (mean = 8). Note: Haney test scores are values from 1 to 50, with a higher score meaning a better result.
Individual nutrient values varied considerably between farm pairs, but on average all eight farm pairs had regenerative crops with:
In addition, the crops from the regenerative farms also had:
Corn, soybeans and sorghum grown in regenerative agriculture had, respectively, on average 17%, 22% and 23% more zinc, while peas and sorghum had more vitamins and soybeans and sorghum had more copper. On average across all crops, regenerative crops had less vitamin B6 and manganese and soybeans had less vitamin C and several B vitamins (B1, B3 and B6). Overall, more significant differences were observed for cabbage, peas and sorghum than for corn and soybeans. There were positive results from a side trial which compared the nutritional values of a cabbage variety from regenerative and organic farming (recently transitioned from conventional) as well as the soil health indicators according to the Haney test. On the organic farm, the soil organic matter content was 2.9% and the Haney test score was 9.2, whereas the regenerative field showed almost four times more organic matter and a soil health score three times higher.
Regarding nutritional composition, the cabbage grown on a regenerative farm was superior to that grown on a tilled organic field:
The last side trial from crop production examined the effect of regenerative agriculture on the mineral content of winter wheat (using the same varieties). Two adjacent fields in northern Oregon were compared, where weed control in between cash crops and total crop rotation were handled differently, but both fields were sown using the direct seeding method. In one field, preemergence and weed control was managed with periodic applications of herbicide (glyphosate) until wheat was planted, and in the other field, a multi-species cover crop mixture was planted and then directly seeded. Mineral fertiliser was applied in the field with herbicide use, while in contrast, compost was applied to the cover crop field.
Wheat in both fields yielded 5 tonnes per hectare. Concentrations of the elements B, Na, Mg, K, Ca, Mn, Fe, Ni, Cu, Zn, Mo and Cd were determined. In total, the wheat samples seeded directly into the cover crops had higher mineral contents, with significantly more boron (41% more), magnesium (29% more), calcium (48% more), zinc (56% more) and molybdenum (4 times more), as well as more potassium (26% more) and manganese (35% more) and 33% less nickel.
The meat samples from each species represented three different types of animal husbandry. For beef, the first sample was from regenerative grazing, where cattle were fed 100 % forage, raised and grazed on restored native prairie and cover crops and fed hay bales in the winter. The second meat sample came from cattle from a regional organic brand that were also fed only forage, but not on regeneratively managed pastures. The third sample was from conventionally raised cattle that were fed corn and soybean meal, silage, and the meal of other conventionally grown grains.
The pork reared regeneratively was raised on pasture after weaning and was also offered a mixture of regeneratively grown ground cereals, usually oats, peas, barley and flax. The second sample came from a local regional health-promoting brand which raised pigs in large barns with access to outdoor space, and the pigs were mostly fed non-GMO corn and soybean meal. The final pork sample was from conventional production where pigs were fed conventionally grown GMO corn and soybean meal throughout their lives.
In this study, the authors monitored and analysed the total omega-3 and omega-6 fatty acid content, alpha-linolenic acid (ALA) and the omega-3 long-chain polyunsaturated fatty acids eicosapentaenoic acid (EPA), docosapentaenoic acid (DPA), docosahexaenoic acid (DHA) and, in beef, conjugated linoleic acid (CLA).
Beef from the regenerative farm had 3 times more omega-3 fatty acids and over 6 times more alpha-linolenic acid (ALA) than conventional beef. Regenerative beef also had 50 % to almost 75 % higher content of the trio of long-chain omega-3 fatty acids (EPA, DPA and DHA) and only two-thirds the content of omega-6 fatty acids as conventional beef. Thus, the ratio of omega-6 to omega-3 was one-fifth that of conventional beef (1.3:1 versus 6.2:1). Values for the regional brand of grass-fed beef were intermediate. The CLA content was 2-fold higher in regenerative beef compared to organic beef and more than 3-fold higher compared to conventional beef. Pork from the regenerative farm had over 9 times more omega-3 and 3 times more omega-6 fatty acids, so the ratio of omega-6 to omega-3 was one-third as high as conventional pork. Pork from the regenerative farm had more than 11 times more ALA, almost 2 times more EPA, 3 times more DPA and more than 4 times more DHA than conventional pork.
Given that the farmers involved in this study were selected on the basis of their success in applying regenerative farming methods, the authors of the study believe that the differences described above can be considered an upper limit to what can be achieved quickly by following the principles of this farming approach. Nevertheless, the consistently higher micronutrient content of regeneratively grown food shows the enormous potential of these soils and soil conservation practices, which, as shown, lead to improvements not only in soil quality but also in the nutritional profile of crops and livestock meat.
It is also interesting to note that each of the regenerative farms was previously managed conventionally and the soil organic matter content was previously similar to that of the paired conventional farm. The resulting analyses show that these practices can increase topsoil organic matter content and improve soil health just a few years after the complete implementation of regenerative practices. In addition, consistently higher soil health scores on regenerative farms indicate the potential for greater nutrient cycling compared to conventionally managed fields.
Although the sample set was small, all three areas of study mentioned above (farm pairs, cabbage comparison and wheat trials) found that, compared to conventionally grown commodities, regeneratively grown crops contain higher levels of key secondary metabolites, vitamins and minerals important for human health. Despite considerable variability between crops and specific farm pairs, the wheat study showed that conventionally grown grain had more Cd, Ni and Na, elements detrimental to human health, while regeneratively grown grain had more micronutrients beneficial to human health. It appears that healthier soils with more soil organic matter and microbial life can increase the micronutrient and health-promoting phytochemical content of harvested products by affecting nutrient cycling and biochemical signalling.
The fatty acid composition and ratios of the regeneratively grazed cattle were significantly better than those of the other rearing methods. It is now understood that forage-based diets compared to cereal-based diets affect the fatty acid composition of meat. Unfortunately, studies comparing meat quality from animals reared on regenerative farms and on conventional pastures are still scarce. The resulting differences show that better soil conditions can have a major effect on meat quality and nutritional value.
The mechanisms and relationships by which regenerative agriculture practices, and hence the soil microbiome, affect the nutrient content of food, and thus human health, deserve more attention not only from experts but also from society as a whole. Only in the future will we be able to fully appreciate the impact of the activities of the soil microbial community on plant, animal and human health. Above all, soil health seems to be strongly influenced by the level of secondary metabolites, which are known to reduce the risk of various chronic diseases and to have a major impact on immunity, overall human health and, most likely, on all other organisms that are entwined in the soil. However, the interconnectedness of soil ecology, the human microbiome and other related topics will be discussed in more detail in subsequent blog posts.
The results of this study, perhaps controversially, point to soil health monitoring as a more appropriate metric for assessing the impact of agricultural practices on the quality and nutritional profile of plant and animal products than the usual division of food to either conventional or organic. Although plant products are currently mainly evaluated based on technological qualities, it can be expected that in the coming years, there will be increasing pressure and demand for a more detailed assessment of the nutritional qualities of food as described above. Clearly, one of our last options to combat the modern epidemic of chronic diseases is to rethink not only what we eat, but also how we grow it. Regenerative agriculture not only offers a solution to the burdensome issues of modern agriculture and our society, but it also comes with the pleasant bonus of better quality food. It, therefore, brings forth a very logical equation - healthy soil equals healthy people.
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