Effect of Soil Organic Matter Content and Volumetric Water Content on ‘Tifway 419’ Hybrid Bermudagrass Growth Following Indaziflam Applications

Indaziflam is a cellulose biosynthesis–inhibiting herbicide for PRE annual weed control in turfgrass systems. Since indaziflam's 2010 U.S. registration, sporadic cases of hybrid bermudagrass injury have been reported; however, causes are not well understood. Field research was conducted from 2013 to 2015 on sandy soil to elucidate the effects of soil organic matter content (SOMC) and soil volumetric water content (SVWC) on plant growth following indaziflam application on established or root-compromised (5 cm long) hybrid bermudagrass. The effect of SOMC was evaluated at two levels, 1.4 (low) and 5.5% (high) w/w at the soil surface (0 to 2.5 cm depth), whereas SVWC was evaluated PRE (2 wk before) and POST (6 wk after) indaziflam application at two levels (low or high). Indaziflam was applied (50 or 100 g ai ha−1) at fall-only, fall-plus-spring, and spring-only timings. Regardless of application timing or SVWC, indaziflam applied at 50 g ha−1 to high SOMC did not cause > 10% visual cover reduction on established or root-compromised hybrid bermudagrass. Indaziflam applied to hybrid bermudagrass on low SOMC exacerbated adverse growth effects, most notably when root systems were compromised before application. Overall, PRE indaziflam application SVWC did not affect hybrid bermudagrass growth. Within low SOMC, low POST indaziflam application SVWC caused less visual hybrid bermudagrass cover reduction than did high POST indaziflam application SVWC, whereas both fall-plus-spring and spring-only application timings caused similarly greater reductions than fall-only indaziflam application. Data from this research will aid turfgrass managers to effectively use indaziflam without adversely affecting hybrid bermudagrass growth. Nomenclature: Indaziflam; hybrid bermudagrass, Cynodon dactylon (L.) Pers. × Cynodon transvaalensis Burtt-Davey ‘Tifway 419’. Indaziflam es un herbicida inhibidor de la biosíntesis de cellulose para el control PRE de malezas anuales en sistemas de céspedes. Desde el registro de indaziflam en Estados Unidos en 2010, se han reportado casos esporádicos de daño en el césped bermuda híbrido, aunque las causas no se conocen bien. Entre 2013 y 2015, se realizó una investigación de campo en un suelo arenoso, para elucidar los efectos del contenido de materia orgánica del suelo (SOMC) y el contenido volumétrico de agua del suelo (SVWC) sobre el crecimiento vegetal después de la aplicación de indaziflam a un césped bermuda híbrido establecido o con un sis