Interseeding crabgrass and berseem clover into sorghum–sudangrass for improved herbage accumulation, nutritive value, and weed suppression

Abstract Sorghum–sudangrass hybrids ( Sorghum. bicolor × Sorghum. bicolor var. sudanense; SSG) are common warm‐season annual forages utilized in forage systems in the northeastern United States. However, weed control can be an issue, particularly in low‐input forage systems. Interseeding annual forages, such as crabgrass ( Digitaria sanguinalis L.; CG) and berseem clover ( Trifolium alexandrinum L.; BC), is of interest to aid in weed control due to their rapid growth and desirable nutritive value. A 2‐year small plot evaluation was conducted to determine the agronomic benefits of interseeding CG and BC via no‐till drill or broadcast seeding into SSG established on different row spacings. Total herbage accumulation (HA) did not differ by year for any of the treatments evaluated ( p > 0.13), despite having different row spacing and companion crop establishment methods. Botanical composition (BOT) varied among treatments ( p < 0.01) for all forage components in both years. In 2022, treatments containing CG had lower percentage of SSG, BC, and weeds (other undesirable plant species), but in 2023 only the weeds percentage was lower in treatments with CG. Crude protein did not differ in either year ( p > 0.55) across treatments; however, treatments containing high amounts of CG had the lowest ( p = 0.03) total digestible nutrients in 2022 only. This study concluded that while row spacing and the interseeding of annual forage species did not affect the overall HA of SSG, they did affect the BOT and nutritive value of the stand. Future research is warranted for evaluating other compatible forages and contrasting defoliation methods to determine their impact on the agronomic production of these types of mixtures, such as grazing or stored forage production.