07
Nov
Organic Banana Production Better for Soil Health than Chemical-Intensive Practices, Researchers Document
(Beyond Pesticides, November 7, 2024) Organic banana production is significantly more conducive to microbial decomposition than its chemical-intensive counterparts in the Caribbean nation of Martinique, according to a recent study published in Applied Soil Ecology. “Macrofaunal decomposition was increased more (55%) than microbial decomposition (20%), indicating that organic farming removes a constraint of conventional farming especially affecting macrofauna.†Biological activity in the soil is foundational to organic land management and critical to the cycling of nutrients that feed plant life while contributing to resiliency and soil water retention.
Bananas are one of the most highly consumed fresh fruits in the U.S. marketplace. A consumer survey conducted by the International Fresh Produce Association in 2023 identified 84% of households purchasing bananas that year. The U.S. Department of Agriculture (USDA) Economic Research Service identifies bananas as the third most consumed fruit product in the United States, with the average person eating 13.2 pounds that year.
Since bananas require specific bioclimatic conditions for commercial production that meets ongoing consumer demand, the proliferation of industrial-scale monoculture banana plantations in various Central and South American countries and territories has and continues to devastate local and Indigenous communities for generations. Environmental justice and public health advocates are invested in pushing for organic agricultural production to move beyond extractive systems that leverage toxic pesticide products at the expense of public health, biodiversity, and community well-being.
Study Analysis
Background and Goals
“Our study aims at improving knowledge on how organic farming affects litter decomposition in a tropical agroecosystem focusing on banana cropping systems in Martinique (Lesser Antilles),†says the study authors.
The authors hope to address an apparent gap in research surrounding the potential impact of organic farming on litter decomposition. In tropical areas with ideal bioclimatic conditions for banana production such as Martinique, “biological activity is supposed to be the driving force of decomposition process.†Therefore, the researchers focus on the impact of organic farming on microbial decomposers (i.e. fungi and bacteria) as well as macrofaunal decomposers (i.e. earthworms, isopods, gastropods, and diplopods).
As an extension of the main goal, researchers proposed two guiding questions to direct this study:
- Does organic farming enhance litter decomposition in the banana cropping systems of Martinique?
- Does glyphosate contamination of banana litter affect its decomposition in situ (in the original place)?
The study authors are researchers at the French Agricultural Research Centre for International Development, or Centre de coopération internationale en recherche agronomique pour le développement (CIRAD), a self-described “French agricultural research and cooperation organization working for the sustainable development of tropical and Mediterranean regions.†The authors received joint funding from the European Regional Development Fund and the Territorial Collectivity of Martinique for this study.
Methodology
The researchers gathered leaf litter samples from banana fields in two distinct bioclimatic zones in Martinique, “the South of Martinique†(South zone) and “central Martinique†(Central zone).
The South zone is known for a relatively dryer climate, Vertisol soil type, and lower mean average annual rainfall; the Central zone, meanwhile, is relatively more humid, Nitisol soil type, and higher average annual rainfall. To ensure uniformity in the data analysis and avoid confounding factors such as soil type in the South zone, the authors “restricted [the] study area to a plain sector with the same soil type, where we interviewed different farmers about their crop management, where [the researchers] interviewed different farmers about their crop management, [the researchers] selected three organic banana fields and three conventional banana fields having the same planting date, similar slope, soil tillage and field area (1.5 hectares/3.7 acres on average).â€
Meanwhile, in the Central zone, “three organic banana fields and three conventional banana fields were selected on an experimental station managed like a farm within the BANABIO project [another CIRAD research initiative].†The fields in the Central zone were smaller than those in the South zone, with a mean area of 500 square meters per field. The authors note that “all fields were banana monocultures†of the Cavendish subgroup of the AAA banana cultivator group (Musa acuminata), the most commonly produced species available to consumers in the global marketplace.
To address the first research question, researchers considered various variables, including field shading by banana canopy, weed soil cover, plant species richness, and macrofaunal decomposer abundance and richness. Five sampling units were established for the South and three for the Central fields due to discrepancies in field size between the two zones. Earthworms (the indicator for macrofaunal decomposition) were hand-sorted and placed in three sampling units on each field. To address the second research question, the authors collected two batches of banana leaf litter samples from randomly selected plants in each field. The first batch was collected from plants injected with glyphosate, and the second batch was destroyed without the use of the pesticide. The leaves were dried outdoors for a week before falling to the ground and transported to the laboratory to quantify glyphosate and one of its degradation products, as well as carbon, nitrogen, and other mineral concentrations.
To test for leaf decomposition and compare rates between organic and conventional fields (as well as glyphosate and glyphosate-free leaf litter), the litter was gathered from randomly selected plants and placed into 264 litter bags on the soil surface of the 12 selected field sites. Seven control bags were placed in a banana field near the laboratory to best monitor the decomposition rates across both the Central and South zones. The bags had large and small mesh sizes to test the microbial versus macrofaunal contributions to decomposition. The “ash-free decomposition rate†was calculated for each bag to “correct this final dry mass for potential soil contamination in the litter.â€
For further details, see the “Materials and Methods†section.
Main Conclusions
The authors arrived at the conclusion that there were notable differences in biological activity and soil health in organic versus non-organic fields. “Mean plant species richness was 55% significantly higher in organic fields and soil weed cover was 79% significantly higher in organic fields than in conventional fields,†says the researchers. The presence of earthworms, macrofauna, and other decomposers was far higher in organic fields. The nitrogen, calcium, and magnesium concentrations “were significantly higher†in glyphosate-free samples.
The type of farming practices and decomposition rate had a significant influence. “Overall litter mass loss was 24% significantly higher in organic compared to conventional fields,†says the researchers. Microbial decomposition was 20% higher in organic fields, with macrofaunal contribution 55% higher in organic fields relative to conventionally grown banana fields. This top-level finding is in alignment with other comparative analyses of decomposition rates of organic and conventional fields in the Netherlands and Ghana.
The researchers hypothesize the three main mechanisms contributing to greater litter decomposition in organic fields:
- “[T]he toxicity of herbicides (especially glyphosate) on macrofauna decomposers in conventional fields.â€
- “[T]he stimulated microbial and macrofaunal activity due to organic fertilization in organic fields ().â€
- “[T]he beneficial effect of vegetation providing more microhabitats and favourable microclimate for both microorganisms and macrofauna, ().â€
Toxic Legacy of Monoculture Banana Plantations
Human rights and environmental advocates consider the continuation of monoculture banana farms a matter of environmental injustice and racism that will also cause lasting public health and biodiversity damage.
In 2019, Central American agricultural workers exposed to the toxic pesticide Nemagon brought back lawsuits in French courts after previously failed attempts back in the 1980s. (See Daily News here). Those lawsuits were prevented from moving forward again in 2022 after the lawyer representing the affected workers shared that the courts “denied our claim because the judges had no jurisdiction over the [pesticide] companies.†This decision follows a precedent in which multinational companies do not face legal consequences for their actions due to arguments of jurisdiction. In 2009, U.S. District Judge Paul Huck said a multimillion-dollar judgment against U.S. food giant Dole and the Dow Chemical Company cannot be enforced because, “[T]he judgment was rendered under a system which does not provide impartial tribunal or procedures compatible with the requirements of due process of law, and the rendering court did not have jurisdiction over Defendants.†(See Daily News here.) Meanwhile, biodiversity and human health are impacted by chemical-intensive banana production as documented by previous Daily News here and here.
Call to Action
Demand for organic bananas is increasing significantly. According to data gathered by the International Federation of Organic Agriculture Movements (IFOAM) and Research Institute of Organic Agriculture (FiBL), bananas, soybeans, and sugar are the topmost imported organic products in the United States. “With more than 1.2 million metric tons and almost 44 percent of the Latin American and Caribbean organic exports, bananas are the most important product group,†says the report (See here.)
Session 1 of Beyond Pesticides’ 41st National Forum, Imperatives for a Sustainable Future—Reversing the existential crises of pesticide-induced illness, biodiversity collapse, and the climate emergency, from October 30, can be viewed here. Session 2 of the Forum continues 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.
All unattributed positions and opinions in this piece are those of Beyond Pesticides.
Source: Applied Soil Ecology
