Forage mass, nutritive value, and economic viability of cowpea overseeded in tall fescue and sorghum‐sudangrass swards

Abstract

AbstractCowpea (Vigna unguiculata L. Walp) (CW) is being considered as an alternative feed source in the southern U.S. Legume–grass mixtures are known to provide greater forage mass compared with unfertilized grass monocultures; however, research is needed to evaluate alternatives for increasing forage availability during the summer. The objective of this study was to quantify forage mass, nutritive value, and economic viability of CW overseeded in tall fescue [Schedonorus arundinaceus (Schreb.) Dumort.] (TF) and sorghum × sudangrass hybrid [Sorghum bicolor (L.) Moench × Sorghum sudanese (P.) Stapf] (SS) swards seeded at different rates. Two experiments were established in Spring Hill, TN, one with TF and the other with SS, from June to September of 2016 and 2017. Inoculated CW seeds were drilled into TF and SS plots at 25, 50, or 75 lb acre−1 and compared with control treatments that were without CW. There were no differences in total and average forage mass of TF or SS with the addition of CW, regardless of the seeding rate, likely due to the competitiveness of the grasses. No differences among seed rates were observed in the concentration of crude protein (CP) for TF swards mixed with CW in either year while in vitro dry matter digestibility (IVDMD) was less for the control treatment in 2017. Meanwhile, the nutritive value of the SS and CW mixture was improved as the CW seeding rate increased in both years. Data from this study suggest that the addition of CW to TF or SS does not justify its cost given the minimal benefit provided.