From Soil to Legal Fate of Soil-Biodegradable Films in the USA

Author : Jacob W. Clements, Douglas G. Hayes, Sean M. Schaeffer

Department of Biosystems Engineering and Soil Science, University of Tennessee (USA)

American researchers present an analysis of the links between regulation and agricultural practices. Let’s examine the interactions between the legal framework, the tools for those working on the ground, and the added value of science.

Soil-biodegradable mulch films (BDMs) offer a promising alternative by eliminating the need for post-use management. But that promise depends on what happens next. A film that truly breaks down in soil can reduce removal and disposal burdens. If it leaves persistent fragments, moves off field, or releases additives, then the situation changes. At that point, “biodegradable” is not only a product claim. It becomes a soil fate question, and eventually a legal one.

The challenge of reconciling legal definitions and scientific terminology

This matters because U.S. environmental law does not have a simple category for BDM fragments after they are incorporated into soil. They are agricultural products when they are applied. They may become residues after use. They may release chemical constituents during degradation. If fragments leave the field, they may look more like pollutants. If degradation fails and the material must be removed, it may look more like conventional plastic waste. Legal treatment depends less on the label on the product and more on what the material does in soil.

This has become even more important after Loper Bright Enterprises v. Raimondo, the Supreme Court decision that ended Chevron deference. Regulators now need clearer statutory authority, stronger evidence, and more precise definitions. A broad claim that “this material is biodegradable” or “this material is a pollutant” may not be enough. The science must show what remains, where it goes, how long it persists, and why that behavior fits within an existing legal category.

A major challenge is that the term “biodegradable” is often used too loosely. Disintegration, mineralization and assimilation are related, but different, terms. A mulch film can visually disappear while some of its carbon remains in the soil. It can fragment before it mineralizes. It can pass a laboratory test but behave differently in a field with cooler temperatures, dry periods, lower microbial activity, or different soil texture.