110 Improving Southern Bermudagrass Pastures with Alfalfa: An Evaluation of the Impacts of Alfalfa Establishment Timing and Crabgrass Competition

Abstract

Abstract Inclusion of alfalfa (Medicago sativa) in bermudagrass (Cynodon dactylon) pastures improves nutritive value, increases grazing days, and reduces the need for synthetic nitrogen fertilizer. Crabgrass (Digitaria sanguinalis) is a very palatable warm-season annual grass with high nutritive value, prolific reseeding ability, and proclivity to volunteer in many southeastern pastures. Crabgrass is a common pest that requires pre-emergent herbicide technologies to control in alfalfa hayfields used to produce stored forage. However, in a grazing system, crabgrass could serve as a key component to a mixture aimed at increasing nutritive value and filling gaps in the grazing season. The purpose of this study is to evaluate the impact of alfalfa establishment timing (fall vs. spring) in bermudagrass pastures in the Coastal Plains, and the resultant impact of crabgrass inclusion rather than removal in alfalfa bermudagrass mixed pastures on nutritive value, botanical composition, forage accumulation, alfalfa stand density and persistence. This on-going two-year study is being conducted in Tifton, GA using a randomized complete block design with 4 replications of the following 6 treatments: Fall Alfalfa + Summer Crabgrass, Fall Alfalfa, Spring Alfalfa + Summer Crabgrass, Spring Alfalfa, Bermudagrass + Synthetic Nitrogen, and Untreated Bermudagrass Control. Data were collected from plots on a 28 to 35-day interval to determine botanical composition, forage availability, and nutritive value. The projected impact of this research is three-fold; first, to identify how differing management strategies for restoring bermudagrass pastures are improved with inclusion of alfalfa. Second, it aims to quantify and support a recommended timing for planting alfalfa in the coastal plains, and third to estimate the impact of crabgrass inclusion in alfalfa bermudagrass systems. Data evaluation and statistical analysis is ongoing for this research and will be finalized in winter 2022.