01
Nov
Study Adds to Understanding of Importance of Soil Health to Ecosystem Stability and Biodiversity
(Beyond Pesticides, November 1, 2024) In a study published earlier this year in Soil Science Society of America Journal, researchers at Kansas State University document direct evidence that organic amendments (e.g., manure and compost) in a no-till agricultural system “facilitat[e] microbial diversity†that cycles plant-available nutrients.
The study was published just as farmers are looking for less expensive practices that support the economic vitality of their farms amid surging prices for petrochemical pesticides and fertilizers and as agricultural support programs are threatened by unresolved issues in Farm Bill talks on Capitol Hill. [See the recent Action of the Week calling on Congress to take action.] Simultaneously, awareness is growing among environmental and public health advocates about the importance of soil health to ecosystem stability in combatting climate change-induced natural disasters and stopping plummeting biodiversity. Demands for new systems rooted in organic principles and land management practices continue to become more widely recognized by farmers, environmentalists, and the broad public. The study adds to earlier findings and contributes to the body of scientific literature on soil health and its importance to ecosystem and human health.
Methodology and Results
The study was led by researchers at Kansas State University specializing in agronomy and chemistry. “The primary aim of this study was to determine soil carbon stabilization mechanisms (in situ) in free soil microaggregates (), collected from a differently managed temperate agroecosystem (no till with N [nitrogen] treatments: manure/compost, urea, and zero fertilizer) by gathering direct evidence using STXM-NEXAFS [near-edge X-ray absorption fine structure spectrometry], while incurring minimal disturbance to the original aggregate microstructure,†say the researchers.
Researchers used STXM-NEXAFS and chemical analysis to aggregate a holistic view of soil health based on soil biology and chemistry. The soil samples were collected in February 2012 from a corn farm established in 1990. [To preserve microbial life in soil samples, researchers confirmed the samples were refrigerated as soon as they were brought in for eventual testing at the Advanced Light Source, Lawrence Berkeley Laboratory, as consistent with other soil health studies led by Professor Ganga M. Hettiarachchi, Ph.D, Professor of Soil and Environmental chemistry at Kansas State University. See here and here.]
Before this, the site was cultivated for grain production (e.g., wheat, oats) for over sixty years. Each sample was gathered at a depth of 0-5 centimeters in 15-20 locations across each plot. “This experiment was established as a split-plot randomized complete block design with four blocks. Main plots represented tillage (conventional till [] and no-till [NT]), and sub plots () were control (no external input), organic amendments/fertilizer (manure/compost), and inorganic fertilizers (urea),†the researchers go on to describe the parameters of the experiment. “In this study, we focused on no-till control, no-till organic amendments/fertilizer, and no-till inorganic fertilizer treatment combinations.†Â
The researchers analyzed the carbon, calcium, iron, aluminum, and silicon clusters in the soil samples at a microscopic level. They arrived at the following four main conclusions after analyzing the three soil microaggregates:
- Direct evidence provided the positive impact of organic amendments on carbon stabilization in free soil microaggregates;
- Microbial-derived carbon was found in microaggregates from manure-/compost-added soils;
- Continuous addition of organic amendments enhances organic carbon (OC) stabilization in soil microaggregates; and
- Integrated approach of STXM-NEXAFS, C-NMR [Carbon-13 nuclear magnetic resonance], and wet chemistry improved our mechanistic understanding.
The investigation of chemical, biological, and environmental impacts of organic amendments, such as manure and compost, resonates with organic advocates who are dedicated to moving beyond synthetic fertilizer products as an immediate fix to mineral deficiencies on their farmland. Carbon stabilization is only sustainable in a healthy soil system. Therefore, the presence of microbial life is an indication that the necessary checks and balances are in place to draw down atmospheric carbon further into the soil ecosystem, rather than leaching into the atmosphere. Organic matter, including compost and manure, is a powerful carbon stabilizer that provides a binding material for other necessary minerals to remain in the soil for crop and plant intake.Â
Soil Health Benefits of Organic Agriculture
Organic advocates acknowledge the surge in academic, popular, and farmer interest in organic land management practices and principles as an important expansion to existing research identifying the soil health impacts of agrochemical products.
For example, peer-reviewed scientific research going back to 2004 establishes a direct relationship between deleterious glyphosate-based herbicides and soil health conditions. A 2022 paper published in Trends in Ecology & Evolution asserts the widespread environmental contamination with these herbicide compounds is influencing soil, plant, and animal microbiomes in ways that are not only not well understood, but also can have significant impacts on the functioning of organisms and their ecosystems—with evolutionary implications. Impacts of herbicides on soil microbiota include disruption to nutrient cycling, as well as altered organism and plant performance, which can affect pollination and animal consumption of plants. This builds on a 2021 study published in Frontiers in Environmental Science by a team of international researchers on the destructive impact of glyphosate on microbial communities, particularly against beneficial microorganisms. Glyphosate acts on the shikimate pathway, present in plants, fungi, bacteria, archaea, and protozoa. Thus, many taxonomic groups of microorganisms are sensitive to glyphosate.
Glyphosate is just one example of an array of pesticide products and agricultural practices that undermine soil microbial activity, which many scientists, farmers, and the pesticide industry itself, acknowledge as a fundamental building block of long-term food system stability. A study published in Nature Ecology and Evolution found various fungicides harm the soil and jeopardize crop yields by reducing the prevalence of beneficial fungi, specifically arbuscular mycorrhizal fungi (AMF). Monoculture agriculture is a form of industrial agriculture that inevitably leads to poor soil health relative to diverse farming systems, based on a 2021 study published in Agrosystems, Geosciences and Environment. Researchers note that the U.S. Corn Belt, which is defined by monoculture farming of genetically engineered corn, has lost 35% of its topsoil. The impact of toxic pesticides on beneficial organisms and nontarget species has contributed to the dramatic loss in insect populations (up to one-quarter of the global population) since 1990, based on a 2024 study published in Environments. A 2020 study published In Communications Biology by scientists at the University of Bern, Switzerland found that beneficial black garden ants (Lasius niger) are adversely impacted by neonicotinoid insecticides.
On this year’s International Microorganism Day, a Daily News reviewed the continuous impact of pesticide residues (glyphosate, paraquat, endosulfan, and diazinon) on the microbial health of farming systems in Nigeria and what it represents for pesticide-dependent farming systems globally.
Meanwhile, various studies identify the significance of organic farming systems in advancing soil health in comparison to chemical-intensive agriculture. In 2022, the Rodale Institute released the findings of its forty-year-long comparative analysis of organic and conventional grain production, finding that:
- Organic systems achieve 3-6 times the profit of conventional farms.
- Yields for the organic approach are competitive with those of conventional systems after a five-year transition period.
- Organic yields during stressful drought periods are 40% higher than conventional fields.
- Organic systems leach no toxic compounds into nearby waterways.
- Organic systems use 45% less energy than conventional farming systems.
- Organic systems emit 40% less carbon into the atmosphere.
A 2024 study published in Biology and Fertility of Soils confirms the soil health benefits of organic agriculture in its ability to improve ecological functions damaged by chemical-intensive farming practices. There are various agroecological practices that demonstrate the growing obsolescence of toxic pesticide products. For example, a 2023 study published in Agriculture, Ecosystems & Environment identifies black soldier fly exoskeletons as a potentially effective organic fertilizer in terms of positive impacts on plant size, flower count, seed production, and pollinator appeal, among other factors, as a soil supplement. Additionally, a 2024 study published in the International Journal of Molecular Sciences demonstrates that biofungicides act as a “sustainable and economically viable alternative†to synthetic fungicides. As chemical-intensive practices impair certain production sectors such as citrus orchards in Florida, scientists are moving forward to establish agroecological, organic-aligned practices through a “push-pull†pest management system. (See Daily News here.)
Call to Action
The proliferation of research and scalable solutions in organic farming is viewed by farmers, retailers, policy advocates, and community leaders as a transformational solution.
Talk with Beyond Pesticides about creating a livable future: Attend Beyond Pesticides’ 41st National Forum, Imperatives for a Sustainable Future—Reversing the existential crises of pesticide-induced illness, biodiversity collapse, and the climate emergency. The Forum launched on October 30 at 2-4pm (EDT) and will continue on November 14 at 1pm (EST). The Forum provides an opportunity to discuss with world-renowned scientists, from Germany and the United States, both (i) the hazards that define the urgency of threats associated with petrochemical toxicants, with a focus on chemicals that disrupt the endocrine system (including pesticides) and lead to life-threatening diseases, and (ii) the strategy for adopting a path forward that tackles the problem holistically, rather than one chemical at a time. Registration is complimentary, with contributions appreciated, and valid for all sessions of the Forum!Â
All unattributed positions and opinions in this piece are those of Beyond Pesticides.Â
Source:Â Soil Science Society of America Journal Â
