Interpretive Summary: The impact of maturity stages on yield, quality, and nutritive value of ensiled Johnsongrass [Sorghum halepense (L.) Pers]

By: Camila S da Silva, Jennifer J Tucker, Fabio J Maia, Jeferson M Lourenço, Morgan L Bass, Darren S Seidel, Todd R Callaway, Dennis W Hancock, R Lawton Stewart, Jr

Johnsongrass [Sorghum halepense (L.) Pers.] is a perennial warm-season grass that was originally introduced to the United States as a forage in the 1830s in South Carolina. If managed properly in a grazing system, Johnsongrass can serve as a quality grazeable forage, however, it is intolerant of heavy grazing due to the depletion of rhizome reserves and will not persist under these conditions (Howard, 2004). Nevertheless, since its introduction, Johnsongrass has become a problematic weed in hay fields and row crops in the Southeast. Johnsongrass has been identified as a major weed in 53 countries around the world (Hartzler et al., 1991). In the United States, the occurrence of Johnsongrass has been reported in all states except Minnesota, Maine, and Alaska (USDA Plants Database, 2017).

Although Johnsongrass is palatable to cattle and has a similar nutritive value to bermudagrass (Dillard et al., 2012), the thick culm (0.5–2.0 cm in diameter; Warwick and Black, 1983) requires longer drying time or additional steps to crush or cut the stem for hay production. Johnsongrass is similar in growth characteristics and belongs to the same genus as forage sorghum [Sorghum bicolor (L.) Moench]; an annual forage option that is commonly conserved as silage. There is potential to utilize Johnsongrass as silage, however, research is limited (Rude and Rankins, 1993). Therefore, the objective of this study was to evaluate the effect of maturity stage at harvest on herbage accumulation, ensiling characteristics, and nutritive value of Johnsongrass. We hypothesized that Johnsongrass can be successfully ensiled as a stored forage, and nutritive value and fermentation quality will be determined by plant maturity at harvest for ensiling.

Read the full article in Translational Animal Science.