Center for Regenerative Agriculture and Resilient Systems

The Science

Each text and photo block below links to the original paper unless it contains more than one link within the text.
Cover crop functional types differentially alter the content and composition of soil organic carbon in particulate and mineral-associated fractions. Zhang et al, Global Change Biology, June 2022
In this study several varieties of cover crops were tested for their effects on soil organic carbon (SOC). All the species tested increased SOC compared to fallow but did so in different ways and to different extents. Multi-species cover crops show potential to capture carbon in the soil most efficiently.
Rates of Historical Anthropogenic Soil Erosion in the Midwestern United States; Thaler, et al; Earth's Future, February 2022
Remnants of native prairie perch high above the surrounding farmland, showing the amount of erosion visually and providing an opportunity to measure historical soil erosion rates. This study used high-resolution topographic surveys conducted at the boundary between 20 prairies and adjacent agricultural fields. Median reduction in soil thickness ranged from 0.04 to 0.69 m, corresponding to erosion rates of 0.2–4.3 mm year−1, with a median value of 1.9 mm year−1. Researchers estimate a median historical erosion rate of 1.8 ± 1.2 mm year−1—almost double the rate considered acceptable by the U.S. Department of Agriculture. 
Impacts of winter cover cropping on soil moisture and evapotranspiration in California’s specialty crop fields may be minimal during winter months, CalAg UCANR , Jan. 13, 2022
Results from a 3-year study suggest that processing tomato and almond growers can adopt winter cover cropping without changing irrigation practices.
Soil health and nutrient density: preliminary comparison of regenerative and conventional farming; Montgomery, et al; PeerJ., January 27, 2022.
Abstract: "Several independent comparisons indicate regenerative farming practices enhance the nutritional profiles of crops and livestock. Measurements from paired farms across the United States indicate differences in soil health and crop nutrient density between fields worked with conventional (synthetically-fertilized and herbicide-treated) or regenerative practices for 5 to 10 years. Specifically, regenerative farms that combined no-till, cover crops, and diverse rotations—a system known as Conservation Agriculture—produced crops with higher soil organic matter levels, soil health scores, and levels of certain vitamins, minerals, and phytochemicals. In addition, crops from two regenerative no-till vegetable farms, one in California and the other in Connecticut, had higher levels of phytochemicals than values reported previously from New York supermarkets. Moreover, a comparison of wheat from adjacent regenerative and conventional no-till fields in northern Oregon found a higher density of mineral micronutrients in the regenerative crop. Finally, a comparison of the unsaturated fatty acid profile of beef and pork raised on one of the regenerative farms to a regional health-promoting brand and conventional meat from local supermarkets, found higher levels of omega-3 fats and a more health-beneficial ratio of omega-6 to omega-3 fats. Despite small sample sizes, all three crop comparisons show differences in micronutrient and phytochemical concentrations that suggest soil health is an under-appreciated influence on nutrient density, particularly for phytochemicals not conventionally considered nutrients but nonetheless relevant to chronic disease prevention. Likewise, regenerative grazing practices produced meat with a better fatty acid profile than conventional and regional health-promoting brands. Together these comparisons offer preliminary support for the conclusion that regenerative soil-building farming practices can enhance the nutritional profile of conventionally grown plant and animal foods."
Soil Health and Nutrient Density: Beyond Organic vs. Conventional Farming; Montgomery, et al; Frontiers in Sustainable Food Systems., November 2021
Recent studies have shown how tillage and synthetic nitrogen fertilizers influence soil health in ways that can reduce mineral micronutrient uptake and phytochemical production by the crops we consume. A review of previous studies and meta-studies finds little evidence for significant differences in crop macronutrient levels between organic and conventional farming practices. However, some significant studies show that organically grown crops contain higher levels of phytochemicals shown to exhibit health-protective antioxidant and anti-inflammatory properties. The authors conclude that part of the long-running controversy over nutritional differences between organic and conventional crops appears to arise from different definitions of what constitutes a nutrient—the conventional definition of dietary constituents necessary for growth and survival, or a broader one that also encompasses compounds beneficial for maintenance of health and prevention of chronic disease. Chronic inflammatory diseases have become epidemic in modern society. This paper makes the case that truly assessing the effects of farming practices on nutrient density and soil health needs to include the micronutrients and phytochemicals that prevent these conditions and support human health maintenance and well-being.
Soil Disturbance Impact on Crop Ergothioneine Content Connects Soil and Human Health; Beelman, et al; Agronomy 2021
Ergothioneine is an amino acid with potent antioxidant and anti-inflammatory effects produced mainly by non-yeast fungi, cyanobacteria, and mycobacteria. Mounting evidence suggests that it can mitigate several chronic diseases of aging, in particular heart disease, Alzheimer's Disease and Parkinson's disease. Although Ergothioneine is not produced by plants it is found in plant products because soil fungi pass on the amino acid to plants through their roots. Soil tillage has been shown to reduce soil fungal biomass. This study tested Ergothioneine contents in maize, soybeans, and oats grown in soil managed with annual moldboard plowing (most intensive), chisel/disking (less intensive), and no-tillage (least intensive). Ergothioneine concentrations declined in all three crops as tillage intensity increased by approximately 30%. Crop yield was also negatively impacted by intensive tillage. This study is one of the first to show that soil health improving practices that minimize soil disturbance can directly impact a key dietary factor associated with human health.
Regenerative Almond Production Systems Improve Soil Health, Biodiversity, and Profit; Fenster, et al; Frontiers in Sustainable Food Systems, August 2021
Coneventional and regenerative almond orchards in California were compared in terms of soil health, biodiversity, yield, and profit. The orchards were chosen to represent what are considered the best practices of each approach. Regenerative practices included reducing or eliminating synthetic agrichemicals, planting perennial ground covers, integrating livestock, maintaining non-crop habitat, and using composts and compost teas. Total soil carbon, soil organic matter, total soil nitrogen, total soil phosphorous, calcium, sulfur, and soil health test scores were all significantly greater in regenerative soils. Water infiltratration was six times faster in regenerative orchard soils. Microbial biomass, plant biomass, and species diversity, were significantly greater in regenerative orchards. Yields were similar in the two systems but profit was twice as high in the regenerative orchards relative to their conventional counterparts. 
Regenerative rotational grazing management of dairy sheep increases springtime grass production and topsoil carbon storage, Ecological Indicators, June 2021
Basque sheep grazingThe aim of this study was to determine the mid-term effect of rotational grazing on soil ecosystem services and evaluate their synergies and trade-offs in the Basque region where pasture lands are being impacted by increased sheep production. Regenerative rotational grazing achieved 30% higher springtime grass production and 3.6% higher topsoil carbon storage than conventional rotational grazing. 
Adaptive multi-paddock grazing enhances soil carbon and nitrogen stocks and stabilization through mineral association in southeastern U.S. grazing lands, Journal of Environmental Management, March 2021
cows in a moveable paddockFrom the Abstract: "Previous research has shown that rotational grazing, specifically adaptive multipaddock (AMP) grazing that utilizes short-duration rotational grazing at high stocking densities, can increase soil C stocks in grassland ecosystems, but the extent and mechanisms are unknown. We conducted a large-scale on-farm study on five “across the fence” pairs of AMP and conventional grazing (CG) grasslands covering a spectrum of southeast United States grazing lands. We quantified soil C and nitrogen (N) stocks, their isotopic and Fourier-transform infrared spectroscopy signatures as well as their distribution among soil organic matter (SOM) physical fractions characterized by contrasting mechanisms of formation and persistence in soils. Our findings show that the AMP grazing sites had on average 13% (i.e., 9 Mg C ha− 1 ) more soil C and 9% (i.e., 1 Mg N ha− 1 ) more soil N compared to the CG sites over a 1 m depth. Additionally, the stocks’ difference was mostly in the mineral-associated organic matter fraction in the A-horizon, suggesting long-term persistence of soil C in AMP grazing farms. The higher N stocks and lower 15N abundance of AMP soils also point to higher N retention in these systems."
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Regenerative agriculture for food and climate; Rattan Lal; Journal of Soil & Water Conservation, Aug. 2020
a plate of meat and asparagus with a tomatoCan regenerative agriculture produce enough nutritious food for the growing and increasingly affluent world population while also reducing and offsetting some anthropogenic emissions? A better question might be HOW to translate the science into clear and decisive action.
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Global patterns and climatic controls of below ground net carbon fixation. Schlesinger, William H. PNAS August 18, 2020
Soil organic carbon is the third-largest carbon stock after oceanic and geological pools. However, drivers and controls of belowground productivity and the fraction of total carbon fixation allocated below ground remain uncertain. This work adds to our understanding of the below ground carbon productivity response to climate change and provides a comprehensive global quantification of root/belowground productivity that will aid the budgeting and modeling of the global carbon cycle.
Soil science beyond COVID-19; Rattan Lal; Journal of Soil and Water Conservation, April 22, 2020
man in a face mask standing in front of a farm fieldThe tragedy of the COVID-19 pandemic has once again indicated the need for protecting, regenerating and sustaining our depleted and fragile soil. This article points out lessons of this crisis that can be used to make a stronger case for paving the way forward to more effectively combat climate change and better ensure food security.
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Cover crop effects on soil carbon dioxide emissions in a semiarid cropping system

New Mexico landscapeCover crops improve soil health and environmental quality by enhancing soil organic carbon sequestration and nutrient cycling in agroecosystems. This study evaluated the effect of cover crops on soil CO2–C emissions, temperature, and water content during cover crop growth from April to October, 2017 and 2018 in New Mexico.

 

Orchard recycling improves climate change adaptation and mitigation potential of almond production systems; E. Jahanzad, etc., Plos One, March 27, 2020

almond orchardRecycling old almond tree biomass in situ prior to replanting an orchard is known as whole orchard recycling (WOR). It has potential as a carbon (C) negative practice to build soil C storage, soil health, and orchard productivity. Researchers in this study tested the potential of this practice for long term C sequestration and found it effective. It also led to higher yields and substantial improvement in soil functioning, including nutrient content, aggregation, porosity, and water retention. 

Effects of herd management and the use of ivermectin on dung arthropod communities in grasslands; J.Pecenka, J.Lundgren, Basic & Applied Ecology, Aug. 24, 2019
dung beetleThis study found that rangelands managed with more regenerative practices and lack of ivermectin applications had greater species richness, diversity, predator species abundance, and dung beetle abundance than more conventionally managed rangelands. The work shows that herd management that aims to mimic intensive grazing of large migrating herds of ruminants can foster dung arthropod community structure, a key trait correlated with nutrient cycling, pest suppression, and productivity of cattle-grazed rangelands.
Case studies on the economic benefits of cover crops, July 2019
almonds on a treeThe American Farmland trust used a USDA Conservation Innovation Grant to quantify the economic and environmental benefits of soil health practices (no-till, strip-till, cover crops, nutrient management, conservation cover, compost application, and mulching). They also used the USDA’s Nutrient Tracking Tool and USDA’s COMET-Farm Tool to quantify the water quality and climate benefits of these practices.
New paper points to soil pore structure as key to carbon storage, July 26, 2019
garden spade in soilNew research by Alexandra Kravchenko, Michigan State University professor in the Department of Plant, Soil and Microbial Sciences, and several of her colleagues provides new insight into how carbon is stored in soils that could support efforts to improve the climate resilience of cropping systems and also reduce their carbon footprints. Read more . . .(opens in new window)  Read the original paper(opens in new window) here.
Conservation agriculture systems; J. P. Mitchell, etc., CAB Reviews, May 29, 2019

field with cover cropsThis paper summarizes how agricultural systems developed into what they are today and identifies ways in which these systems will need to be improved to meet future food security challenges. The core principles and concepts of conservation agriculture (CA) systems provide an important unifying framework. The paper provides evidence for why these systems, when flexibly applied and in ways that mimic natural ecosystems, provide the best approach for moving forward.

Harnessing Soil Microbes to Improve Plant Phosphate Efficiency in Cropping Systems; A. Kafle, etc., Agronomy, March 2019
shovel of soil Bioinoculants are an increasing trend in agricultural practices. This review explores recent advances in our understanding of how arbuscular mycorrhizal fungi, ectomycorrhizal fungi, and phosphate-solubilizing bacteria help solubilize inorganic phosphate from insoluble forms and allocate it directly to crop plants.
Worldwide decline of the entomofauna: A review of its drivers; F. Sánchez-Bayo; Biological Conservation; Jan. 25, 2019
dead insectAbstract: "Biodiversity of insects is threatened worldwide. Here, we present a comprehensive review of 73 historical reports of insect declines from across the globe, and systematically assess the underlying drivers. Our work reveals dramatic rates of decline that may lead to the extinction of 40% of the world's insect species over the next few decades."
Soil organic matter underlies crop nutritional quality and productivity in smallholder agriculture; S. Wood, etc., Agriculture, Ecosystems & Environment, Nov. 2018
wheat fieldAbstract: "Global crop yield gains have not been associated with increases in the many macro- and micro-nutrients needed for a balanced human diet. There is thus growing interest in improving agricultural practices to increase nutrient availability to people. Because nutrients in crops come from soil, soil management—such as building soil organic matter—could be a tool in managing agriculture to produce more nutritious food. To understand the relationship between soil organic matter and nutritional quality, we measured soil organic matter fractions, crop yield, and wheat nutrient composition on smallholder farms along a land-use and land-cover gradient in Ethiopia. We found that wheat yields and protein content were related to organic matter nitrogen, and zinc content was related to organic matter carbon."
Is the future of agriculture perennial? Imperatives and opportunities to reinvent agriculture by shifting from annual monocultures to perennial polycultures; T. Crews, etc.; Cambridge University Press, Nov. 2018
Barley, a Perennial GrainAbstract: "Modern agriculture is associated with numerous environmental predicaments, such as land degradation, water pollution, and greenhouse gas emission. Socio-economically, it is characterized by a treadmill of technological change, increased mechanization, and economic consolidation, while depressing economic returns to farmers. A root cause is the dominance of annual plants cultivated in monocultures. Annual crops require the yearly clearing of vegetation resulting in soil erosion and other forms of ecosystem degradation. Monocultures are susceptible to agricultural pests and weeds. By contrast, perennial polycultures informed by natural ecosystems, promise more sustainable agroecosystems with the potential to also revitalize the economic foundation of farming and hence rural societies."
Spider community shift in response to farming practices in a sub-humid agroecosystem of southern Africa, N. Mashavakure; Agriculture, Ecosystems and Environment; Nov. 2018

Jumping SpiderAbstract: "Most spiders are generalist predators and important biological control agents of various insect pests of agricultural crops. A study was conducted to determine the impact of cultural practices on the abundance and diversity of soil surface-dwelling spiders (Araneae). Two experiments were conducted at the Chinhoyi University of Technology experimental farm, Zimbabwe, over the 2013/2014 and 2014/2015 cropping seasons."

Climate Change Trends and Impacts on California Agriculture: A Detailed Review, T.B. Pathak, Agronomy, Feb. 2018
Map of California showing the Agricultural Vulnerability index.California is a global leader in the agricultural sector and produces more than 400 types of commodities. The state produces over a third of the country’s vegetables and two-thirds of its fruits and nuts. Despite being highly productive, current and future climate change poses many challenges to the agricultural sector. This paper provides a summary of the current state of knowledge on historical and future trends in climate and their impacts.
Regenerative agriculture: merging farming and natural resource conservation profitably; C. LaCanne, J. Lundgren, PeerJ, Feb. 26, 2018
corn plantThis paper evaluates the relative effects of regenerative and conventional corn production systems on pest management services, soil conservation, and farmer profitability and productivity. It shows that regenerative farming systems provided greater ecosystem services and profitability for farmers than an input-intensive model of corn production. Regenerative fields had ten times fewer pests. And even though regenerative fields had 29% lower yields, profits were 78% higher than traditional corn production systems.
Root biomass and exudates link plant diversity with soil bacterial and fungal biomass; N. Eisenhauer; Scientific Reports; April 4, 2017
earthworms in soilAbstract: "Plant diversity has been shown to determine the composition and functioning of soil biota. Although root-derived organic inputs are discussed as the main drivers of soil communities, experimental evidence is scarce. While there is some evidence that higher root biomass at high plant diversity increases substrate availability for soil biota, several studies have speculated that . . ." Read more now . . .(opens in new window)
Soil Fungal:Bacterial Ratios Are Linked to Altered Carbon Cycling; A. Malik, etc., Frontiers in Microbiology; August 9, 2016
soil fungusDespite several lines of observational evidence, there has been a lack of consensus on whether higher fungal:bacterial (F:B) ratios directly cause higher soil carbon (C) storage. This team employed RNA sequencing, protein profiling and isotope tracer techniques to evaluate whether differing F:B ratios are associated with differences in C storage. In the experiments they performed the increased abundance of fungi in both soils and the altered C cycling patterns in the F:B dominated soils highlight the significant role of fungi in litter decomposition and indicate that F:B ratios are linked to higher C storage potential.
The role of ruminants in reducing agriculture’s carbon footprint in North America; W.R. Teague, etc., Journal of Soil and Water Conservation, April 2016
cow grazingBecause of the methane produced by rumen fermentation, ruminants are a source of greenhouse gas and are perceived as a problem. However, research shows that ruminants consuming only grazed forage cover plants under appropriate management result in more C sequestration than emissions. This research editorial concludes that incorporating forages and ruminants into regeneratively managed agroecosystems should be advanced as a policy. It can elevate soil organic C, improve soil ecological function by minimizing the damage of tillage and inorganic fertilizers and biocides, and enhance biodiversity and wildlife habitat. Read the entire editorial. (PDF)
Which agricultural management interventions are most influential on soil organic carbon (using time series data)? N.R. Haddaway; Environmental Evidence; Jan. 29, 2016
cows in a fieldAbstract: "Loss of soil organic carbon (SOC) from agricultural land is identified as one of the major threats to soils, as it influences both fertility and the production of ecosystem services from agriculture. Losses of SOC across regions are often determined by monitoring in different land use systems. Results from agricultural field experiments can reveal increasing SOC stocks after implementation of specific management practices compared to a control, though in time series experiments the relative rate of change is often negative and implying an overall loss."
Harnessing phytomicrobiome signaling for rhizosphere microbiome engineering; Liliana Quiza et al; Frontiers in Plant Science; July 14, 2015
soil fungiAbstract: "The goal of microbiome engineering is to manipulate the microbiome toward a certain type of community that will optimize plant functions of interest. For instance, in crop production the goal is to reduce disease susceptibility, increase nutrient availability increase abiotic stress tolerance and increase crop yields. Various approaches can be devised to engineer the plant–microbiome, but one particularly promising approach is to take advantage of naturally evolved plant–microbiome communication channels."
Emerging land use practices rapidly increase soil organic matter; Machmuller et al; Nature Communications; April 30, 2015
cow grazingFrom the Abstract: "In a region of extensive soil degradation in the southeastern United States, we evaluated soil C accumulation for 3 years across a 7-year chronosequence of three farms converted to management-intensive grazing. Here we show that these farms accumulated C at 8.0 Mg ha−1 yr−1, increasing cation exchange and water holding capacity by 95% and 34%, respectively. Thus, within a decade of management-intensive grazing practices soil C levels returned to those of native forest soils, and likely decreased fertilizer and irrigation demands."
Plant diversity increases soil microbial activity and soil carbon storage; M. Lange; Nature Communications; April 7, 2015
multi-species cover cropPlant diversity strongly influences ecosystem functions and services, such as soil carbon storage. However, the mechanisms underlying the positive plant diversity effects on soil carbon storage are poorly understood. We explored this relationship using long-term data from a grassland biodiversity experiment (The Jena Experiment) and radiocarbon (14C) modeling.
Plant species richness promotes soil carbon and nitrogen stocks in grasslands without legumes; Wen-Feng Cong et al; Journal of Ecology, 2014
Grassland landscape An 11-year grassland biodiversity experiment investigated whether plant diversity affects soil C and N storage in the absence of legumes. They found that soil C and N stocks increased by 18% and 16% in eight-species mixtures compared to the average of monocultures of the same species, respectively. Enhanced soil C and N stocks also showed a positive feedback to plant productivity via enhanced N mineralization, which could further accelerate soil C and N storage in the long term.
Carbon Sequestration: Position of the Soil Science Society of America; SSSA Ad Hoc Committee S893; Oct. 25, 2001

Hands holding soil with an earthworm in itIncreased long term (20-50 year) sequestration of carbon in soils, plants and plant products will benefit the environment and agriculture. Crop, grazing, and forestlands can be managed for both economic productivity and carbon sequestration. In many settings this dual management approach can be achieved by applying currently recognized best management practices such as conservation tillage, efficient nutrient management, erosion control, use of cover crops and restoration of degraded soils. PDf (PDF)