There are a number of native warm-season grasses (NWSGs) that are well-adapted to growth in the eastern U.S. They are highly productive in summer months, a period when commonly used cool-season grasses are less productive. But in spite their productivity, concerns with forage quality and early season forage availability have limited NWSG adoption by producers.

Research from a prominent Mid-Atlantic university has found that interseeding cool-season legumes into stands of NWSGs could improve these drawbacks and provide high-quality forage and production earlier in the season.

Presenting “Legume Establishment in Native Warm-Season Grass Pastures” at this year’s American Forage & Grassland Council conference were Kathryn Payne, applied forage systems specialist, Southern Piedmont Ag Research & Extension Center, and Carter Phillips, MS graduate, School of Plant & Environmental Sciences, both of Virginia Tech.

They developed a study to evaluate the effects of timing and seeding, the method of seeding and the efficacy of burning on legume establishment in pastures with the NWSGs big bluestem, little bluestem and Indiangrass.

The study took place in Blackstone, VA, at the Southern Piedmont Agricultural Research & Extension Center in 2022 and 2023. Forage varieties included ‘Niagara’ big bluestem, ‘GA ecotype’ Indiangrass, ‘Camper’ little bluestem, ‘Freedom HR’ red clover and ‘Alice’ white clover.

Leading legumes toward pasture success

Several factors were studied, including seeding timing (autumn or winter), seeding method (drill or broadcast), whether or not a plot was burned, all compared against a control plot.

The drill seeded sites used 4 lb./acre of red clover and 1 lb./acre of white clover. The broadcast seeded sites used 6 lb./acre and 1.5 lbs./acre for red and white clover, respectively.

The Virginia Tech researchers measured the amount of clover emergence in each plot, the overall botanical composition prior to harvest and each plot’s forage yield and forage nutritive data. They specifically measured the effect of planting timing and burn status on the number of clover plants per square foot during the establishment year.

Burning appeared to be beneficial, as the reduction of residue in those plots led to higher clover emergence. Plots planted in winter fared much better than those planted in autumn (which saw only negligible clover emergence, regardless of the planting method).

The winter-planted/burned plot produced more than 20 clover plants per square foot when drill seeded; the winter-planted/no burn site saw about 15 plants/square foot. The autumn-planted plot only saw one or two clover plants per square foot.

Regardless of the seeding method, the second harvest resulted in much greater clover composition than the first.

Interestingly, the plots that planted via no-till drill produced the greatest clover composition (28.6% clover) – but those that were broadcast seeded saw statistically similar results to the unplanted control.

During the second year of production, red clover actually suppressed NWSG growth and dominated the plots where residue was burned, including the unplanted control. This led the researchers to conclude that other legume species should be evaluated for compatibility with NWSG species.

The clover content at the winter-planted sites also increased in the second year, while clover content in the autumn-planted ones remained negligible. The research team also determined that burning residue before planting in late winter can result in the greatest clover emergence.

Another year of data is being collected to evaluate clover and NWSG persistence. However, if you want to try this in your own pastures, start planning now for the variety of clover you will plant this coming winter.

by Courtney Llewellyn