Published in Agricultural Ecology and Environment, the review examines how biochar, microplastics, and naturally occurring soil organic carbon interact across several physical and biological scales. The researchers describe agricultural soil as a complex network of pores, mineral surfaces, aggregates, water films, and microbial habitats. Biochar and microplastics can occupy many of the same spaces, meaning their effects may overlap, reinforce one another, or change over time as particles weather and move through the soil.

Biochar can influence the soil carbon cycle in several ways. Its porous structure provides surfaces that can adsorb dissolved organic matter, including compounds that would otherwise be rapidly consumed by microbes or transported away with water. Biochar may also encourage the formation of soil aggregates, in which organic material becomes physically protected from decomposition. In addition, its surfaces can promote associations between organic molecules and soil minerals. These processes may slow the breakdown of carbon and alter the availability of nutrients and water.

Microplastics, however, can disrupt the same soil architecture. Tiny plastic particles change pore size and connectivity, potentially affecting the movement of water, oxygen, dissolved organic matter, and microorganisms. Their impact depends on the type of polymer involved, as well as particle shape, concentration, size, weathering, and the chemical properties of the surrounding soil. Some microplastics may stimulate microbial activity by providing surfaces for biofilms, while others can limit oxygen diffusion, alter moisture conditions, or interfere with microbial communities responsible for decomposing organic matter.

The review emphasizes that the combined effect of biochar and microplastics cannot be predicted simply by adding together their separate effects. Biochar may partially reduce some disturbances associated with microplastics by improving aggregation or offering additional surfaces onto which plastic-associated chemicals and dissolved organic compounds can attach. This could reduce the mobility of certain contaminants or change their availability to soil organisms. Yet the authors caution that the protective capacity of biochar may decline as both materials age, fracture, become coated with organic matter, or fill available sorption sites.

This aging process is especially important because soil is not a static environment. Rainfall, repeated wetting and drying, root growth, freeze-thaw cycles, and microbial activity can gradually alter biochar surfaces and break larger plastic fragments into smaller particles. Weathered microplastics may become more chemically reactive or develop cracks and oxygen-containing functional groups. At the same time, aged biochar may lose some of its original surface characteristics while gaining new mineral and microbial coatings. These transformations could change how carbon is stored, transported, and decomposed over years or decades.

The most immediate concern raised by the researchers involves carbon accounting. Standard soil organic carbon tests generally measure the amount of carbon in a soil sample, but they may not reliably distinguish among carbon derived from plants, carbon transformed by fire and added as biochar, and carbon contained in fossil-fuel-based plastic polymers. That distinction matters because these carbon pools have different origins, chemical structures, environmental behaviors, and implications for climate mitigation. A soil sample containing microplastics could therefore appear to hold more organic carbon even when part of that measurement represents persistent synthetic material rather than newly sequestered atmospheric carbon.

The potential scale of this problem is substantial. According to the review, if microplastic-derived carbon is not separately identified, concentrations equivalent to approximately 0.1% to 0.5% carbon in the upper 20 centimeters of an agricultural plough layer could contribute roughly 3 to 15 megagrams of carbon per hectare to routine soil carbon measurements. The estimate does not mean that every field contains this amount, nor that all measured polymer carbon would be counted as climate mitigation. Instead, it illustrates how synthetic carbon could create a false-positive signal in monitoring systems, especially where projects receive credits for increasing soil carbon stocks.

That issue directly affects measurement, reporting, and verification, or MRV, systems used by soil carbon programs and carbon removal markets. The authors propose an evidence-tiered framework combining polymer-specific analyses with techniques capable of separating pyrogenic carbon from native soil organic carbon. Such methods could include chemical and spectroscopic approaches that identify polymer signatures, assess the structure of fire-derived carbon, and track changes in carbon pools over time. Improved sampling strategies will also be necessary because microplastics and biochar are unlikely to be distributed evenly through a field; they may accumulate near soil surfaces, in irrigation pathways, or within particular aggregate fractions.

The review concludes that long-term field studies are urgently needed. Much of the existing evidence comes from short laboratory experiments using high concentrations of relatively uniform plastic particles and freshly produced biochar. Real agricultural soils contain weathered plastics of different sizes and compositions, mixed with roots, minerals, microorganisms, fertilizers, and changing moisture conditions. Future research will need to follow these systems over multiple growing seasons while measuring greenhouse-gas emissions, microbial activity, carbon chemistry, particle movement, and crop responses. The central message is clear: agricultural soils increasingly contain biogenic, pyrogenic, and synthetic carbon at the same time, and credible climate accounting will depend on telling those carbon sources apart.

Subject of Research: Biochar–microplastic interactions in agricultural soils and their implications for soil carbon storage and measurement

Article Title: Biochar-microplastic co-occurrence in agricultural soils: interfaces, effects on soil organic carbon, and implications for measurement and verification

News Publication Date: 28-May-2026

Web References: https://doi.org/10.48130/aee-0026-0014

References: Yang Z, Simarani K, Zhang X, Di Martino A, Chen Y, et al. 2026. “Biochar-microplastic co-occurrence in agricultural soils: interfaces, effects on soil organic carbon, and implications for measurement and verification.” Agricultural Ecology and Environment 2: e017. DOI: 10.48130/aee-0026-0014

Image Credits: Zhimei Yang, Khanom Simarani, Xi Zhang, Antonio Di Martino, Yi Chen, Yonglei Jiang, Binbin Hu, and Xiaodong Chen

Keywords

Biochar, microplastics, agricultural soils, soil organic carbon, carbon sequestration, soil carbon accounting, climate mitigation, pyrogenic carbon, synthetic carbon, measurement reporting and verification, soil microbiology, greenhouse gases, carbon removal, soil aggregates

Microplastics are tiny plastic particles, often less than five millimeters in size, resulting from the degradation of larger plastic debris or produced intentionally for various applications like cosmetics and industrial activities. Their durable nature allows them to persist in the environment, accumulating in both terrestrial and marine ecosystems. This persistence creates a fertile ground for research that delineates how these minuscule particles might affect the soil’s complex biological and chemical systems, which are crucial for sustaining plant life.

The study’s authors delve deep into the multifaceted interactions between microplastics and soil organisms, illustrating how even small quantities of these pollutants can significantly alter soil structure, fertility, and the health of microbial communities that facilitate essential nutrient cycles. Soil health is foundational for plant growth, and the introduction of microplastics may lead to a disruption that compromises not only the immediate vegetation but also the long-term viability of agricultural lands.

Furthermore, their research highlights the uptake of microplastics by plants, leading to potential bioaccumulation and alteration of physiological processes within plant systems. This phenomenon raises significant concerns about food safety and the ecological implications beyond just soil health. Considering that plants are primary producers in the food chain, any adverse effect on their development could have cascading effects through the ecosystem, impacting herbivores and subsequently, the predators that rely on them for sustenance.

The authors also investigate the pathways through which microplastics enter soils, which include wastewater irrigation, the application of biosolids, and atmospheric deposition. Each of these pathways poses a unique risk associated with the introduction of microplastics into agricultural lands and natural ecosystems. This research calls for a comprehensive assessment of the agricultural practices that might inadvertently contribute to microplastic contamination, urging policymakers for immediate actions to mitigate their spread.

An intriguing aspect of this research is its emphasis on the soil microbiome, composed of diverse microorganisms that play crucial roles in soil health. Microplastics can act as vectors for hazardous chemicals, potentially harming beneficial microbes and allowing pathogenic species to proliferate. Alteration of the microbial community presents a worrying trend since these organisms are vital for nutrient cycling and plant health, and their disruption could lead to reduced agricultural productivity.

As the global community continues to confront the climate crisis and seeks sustainable solutions for food security, understanding the implications of microplastics becomes essential. The authors of this study advocate for integrating microplastic considerations into soil health assessments and agricultural policies. This integration would pave the way for a more holistic approach to sustainability, recognizing the interplay between soil health, plant development, and broader environmental goals.

Science has long known the critical role of healthy soils in supporting agriculture, yet the potential threat posed by microplastics warrants a re-evaluation of our approaches to environmental conservation and food production. The findings underscore the urgency for further research and greater public awareness regarding the pervasive presence of microplastics in our soils.

Collaboration between scientists, policymakers, and stakeholders in the agricultural sector is essential to address this growing concern. This could encompass developing better plastic waste management practices, enhancing recycling protocols, and fostering innovations in biodegradable materials. The research illuminates the need for a collective effort to tackle plastic pollution at all levels of society, ensuring that future generations inherit a healthier planet devoid of continuing ecological damage.

Moreover, education surrounding the importance of minimizing plastic usage and encouraging sustainable practices must also be prioritized. Engaging communities in restoring and protecting local ecosystems may help mitigate the adverse effects of microplastics, fostering resilience and sustainable practices. By focusing not solely on mitigating pollution but also on fostering a culture of stewardship towards the environment, we can work towards reversing the tide of microplastic contamination in our soils.

In conclusion, the study conducted by Manhas, Anjali, and Malviya opens a critical dialogue about the hidden dangers of microplastics within soils, extending beyond mere contamination concerns. Their research brings to light the intricate connections between soil health, plant growth, and environmental integrity, thereby calling for a renewed focus on addressing plastic pollution comprehensively. The implications of their findings serve as a reminder that our interactions with the environment must be rethought in light of the emerging threats posed by human activity.

As we advance into a future facing significant environmental challenges, understanding the far-reaching impacts of microplastics is crucial. It is not merely about cleaning up our plastic waste; it is about creating sustainable systems that will protect our soils, our plants, and our entire ecosystem from the pervasive threat of plastic pollution. In the end, fostering such awareness and advocating for immediate action may hold the key to safeguarding our environmental future.

Subject of Research: Microplastics in soil and their effects on plant health.

Article Title: Ubiquitous presence of microplastics with implication on soil health and plant development.

Article References:
Manhas, S., Anjali, A., Malviya, T. et al. Ubiquitous presence of microplastics with implication on soil health and plant development.
Environ Monit Assess 197, 1043 (2025). https://doi.org/10.1007/s10661-025-14360-4

Image Credits: AI Generated

DOI:

Keywords: Microplastics, soil health, plant development, environmental pollution, sustainability, agriculture.