Eco-friendly Additives for Biodegradation of Agricultural Mulches

EPA Grant Number: SU835534
Title: Eco-friendly Additives for Biodegradation of Agricultural Mulches
Investigators: Hayes, Douglas G , DeBruyn, Jennifer , Lee, Jaehoon , Wadsworth, Larry C
Current Investigators: Hayes, Douglas G , Burnham, Alana , DeBruyn, Jennifer , Ji, Xiaoci , Lee, Jaehoon , Powell, Matthew Shafer , Wadsworth, Larry C
Institution: University of Tennessee - Knoxville
EPA Project Officer: Hahn, Intaek
Phase: I
Project Period: August 15, 2013 through August 14, 2014
Project Amount: $15,000
RFA: P3 Awards: A National Student Design Competition for Sustainability Focusing on People, Prosperity and the Planet (2013) RFA Text |  Recipients Lists
Research Category: Pollution Prevention/Sustainable Development , P3 Challenge Area - Materials & Chemicals , P3 Awards , Sustainability


The objective of this project is to determine robust amendments that can be applied to biodegradable agricultural plastic mulches, particularly novel 100% biobased prototypes prepared by the applicants using nonwovens textile technology, near the end of their service life that will accelerate the mulches’ full microbial conversion into CO2 and water subsequent to them being plowed into the soil.  Plastic mulches, most of which are prepared from non-renewable polyethylene, although serving as important components of sustainable agriculture, due to their aid in enhancing water and soil conservation, their overall sustainability is poor due to limited and undesirable end-of-life alternatives.  Commercially available biodegradable mulches undergo mechanical weakening, which accompanies the initiation of microbial activity, in an uncontrollable fashion.  This project involves a novel approach that will lead to a more controlled, “triggerable,” onset of biodegradation.


Several different amendments that will “open up” the supramolecular structure of the mulches’ polymer molecules and / or help establish microbiological communities capable of microbially assimilating the mulches will be applied to “biodegradable” mulches (both commercially available biodegradable films and experimental biobased nonwovens) at the end of a 5 month service life, to determine if the rate and extent of biodegradation is enhanced. 

Expected Results:

The main output is a new method to facilitate microbial assimilation of “biodegradable” agricultural mulches through addition of amendment(s) to the mulches at the end of their service life, prior to their being plowed into the soil.  The outcome is the identification of the most effective amendment(s) that will increase the rate of biodegradation and lead to a “triggerable” functionality to control the timing of biodegradation, and will ultimately facilitate achievement of the criteria given in a new standard being developed by ASTM for biodegradation in soil ecosystems (WK 29802), requiring the mulches’ carbon atoms to be converted into CO2 at the 90% level in 2 years. For an amendment to be successful, the treated mulch must comply with “inherent” biodegradability specification given within the standard for “compostability”, ASTM D6400, stating that 70% of C atoms must be converted into CO2 within 3 months under the conditions of ASTM using testing method D5338. The proposed EPA P3 project will further develop strategies for biodegradable mulches to reach performance expectations, and to ultimately be converted into CO2 and water at the end of its service life.  In addition, the project will particularly help the performance of 100% biobased mulch prototypes developed by the applicants, which will ultimately be “carbon-neutral” in its net production of CO2, a greenhouse gas associated with climate change.

Supplemental Keywords:

agricultural mulches, agricultural plastics, biodegradation, biopolymers, environmentally benign endpoints, nonwovens, organic agriculture, polyethylene (replacement for), renewable (biobased) feedstocks, sustainable agriculture;

Progress and Final Reports:

  • Final Report