Nutritive value and economic responses under different restoration strategies of cool-season grass pastures

Abstract

Though costly, pasture restoration is necessary when forage stands decline. Interseeding legumes (e.g., alfalfa, Medicago sativa L.), along with crabgrass (CG; Digitaria sanguinalis L.) as a warm-season forage with high nutritive value, can play a key role in supporting pasture restoration. Our objective was to quantify changes in forage mass (FM) and nutritive value and the associated cost of pasture restoration using different strategies. The experiment was carried out in Spring Hill, TN, for 2 years in established swards of tall fescue [TF; Schedonorus arundinaceus (Schreb.) Dumort] or orchardgrass (OG; Dactylis glomerata L.), with the addition of alfalfa with or without CG. The treatments were: 1) control (C-TF or C-OG), 2) synthetic N fertilization (TF+N or OG+N), 3) fall seeding of alfalfa (FA), 4) spring seeding of alfalfa (SA), 5) fall seeding of alfalfa + summer seeding of CG (FA+CG), and 6) spring seeding of alfalfa + summer seeding of CG (SA+CG), with four replications. The FM was greatest when N fertilizer was applied to TF and OG. In both grass types, N fertilization also resulted in greater nutritive value than the control. The addition of alfalfa and CG did not result in an increase in nutritive value, and this response probably may be pronounced in the medium to long term when overseeded species are well established. Thus, synthetic N still incorporates greater outcomes, showing the need for long-term researchers to provide deeper information into overseeding cool- and warm-season grasses, thereby contributing to the restoration of ecosystems.