Preemergent Herbicide Protection Seed Coating: A Promising New Restoration Tool

Invasive annual grasses such as cheatgrass (Bromus tectorum L.) outcompete native grasses, increase fire frequency, and impact the functionality and productivity of rangeland ecosystems. Preemergent herbicide treatments are often used to control annual grasses but may limit timely restoration options due to negative effects on concurrently planted desired seeded species. We tested the efficacy of activated carbon-based herbicide protection coatings applied to individual bluebunch wheatgrass (Pseudoroegneria spicata [Pursh] A. Love) seeds for protecting seedlings from injury associated with pre-emergent herbicide (imazapic) application in a laboratory environment. Emergence of coated seed averaged 57% +/- 5% compared with bare seed, which had 14% +/- 10% emergence with imazapic application. Seedling height for coated seed averaged 7.56 +/- 0.6 cm compared with 2.26 +/- 0.4 cm in uncoated bare seed in the presence of imazapic. Coated seeds produced 87% more plant biomass than uncoated seeds. Our laboratory results suggest that treating individual seeds with an activated carbon-based coating dramatically reduces negative effects of pre-emergent herbicide on desired seeded species. Field studies are needed to confirm these results in an applied restoration context. Published by Elsevier Inc. on behalf of The Society for Range Management.

Automated summary

Invasive annual grasses like cheatgrass can disrupt native grasses and affect rangeland ecosystems. Preemergent herbicides may limit restoration options, but using activated carbon-based coatings on individual seeds can significantly reduce the herbicide's negative effects and increase plant biomass. Further field studies are needed to validate these findings.