Biodegradable
mulches are considered a promising alternative to
polyethylene-based, nonbiodegradable mulch for sustainable agriculture.
In the present study, a bioactive 2-methyl-4- cholorophenoxyacetic
acid/poly(3-hydroxybutyrate-
co
-3-hydroxyvalerate)
(MCPA-PHBV) conjugate blended with biodegradable poly(butylene adipate-
co
-terephthalate/polylactide (PBAT/PLA) was developed and
used as mulch under controlled condition greenhouse pot experiment
with fava bean (
Vicia faba
) as the nontarget crop
species. The objectives were to examine the effectiveness of sustained-release
of MCPA herbicide from biodegradable mulch for broadleaf weed suppression
and to assess any adverse effects of the herbicide on the nontarget
species (fava bean). The energy-dispersive X-ray spectroscopy analysis
(EDS) suggests that a substantial quantity of the herbicide was released
from the biodegradable mulch which effectively killed the broadleaf
weed species even at 1% MCPA concentration. However, the higher concentrations
of the herbicide adversely affected several physiological parameters
of fava bean growth and development. Stomatal conductance decreased,
while leaf temperature subsequently rose (at MCPA concentrations 5,
7.5, and 10%). The quantum yield of the Photosystem II (PSII) indicates
that the photosynthetic efficiency was also restricted at concentrations
7.5% and 10%. Evidently, this slow-release herbicide system worked
efficiently for broadleaf weed control but at higher concentrations,
resulted in adverse physiological effects on the nontarget crop species.
This study has demonstrated that biodegradable mulches containing
MCPA herbicide are able to effectively inhibit the growth of broad
leaf weed species and may be of potential importance in a wide variety
of horticultural and agricultural applications.