Switchgrass Establishment Influenced by Cover Crop, Tillage Systems, and Weed Control

Successful establishment of switchgrass (Panicum virgatum L.) is often challenging. The objective of this study was to improve switchgrass stand establishment through integrated management practices that included cover crops, tillage systems and herbicide application. The study was conducted at the University of Massachusetts Agricultural Experiment Station in Deerfield during the growing seasons of 2012 and 2013. A split split-plot design with three replications was used in both years. The main plots consisted of three cover crop treatments (fallow, oat [Avena sativa L.], and rye [Secale cereale L.]). The sub-plots were two seeding methods (no-till drill, and cultipacker seeder [Brillion]). The sub sub-plots were herbicide treatments that consisted (1) pre-emergence (PRE) application of atrazine (A) and quinclorac (Q) and (2) a Broad Spectrum application of PRE A + Q that was supplemented with post-emergence (POST) application of 2,4-D and dicamba. The no-till seeding method in both years resulted in higher stand density and biomass. Weed control was improved with the Broad Spectrum herbicide (0.90 Mg ha−1) compared with A + Q treatment (1.3 Mg ha−1). No-till seeding produced considerably higher tiller numbers (190 tiller m−2) than that of cultipacker seeder which in turn resulted in significant weed suppression. In general, when planted after rye, switchgrass produced fewer tillers than after oat or fallow. No-till seeding into oat mulch with the application of Broad Spectrum herbicides resulted in highest switchgrass yield (2,098 kg ha−1) in the establishment year.