E stablishing clover (Trifolium spp.) into permanent pasture can be challenging, because many factors like competition from existing the sward, subsequent grazing management, or weather fl uctuations can aff ect this process. Two common overseeding methods for clover include surface sowing without disturbance (broadcasting) or drilling of seed through undisturbed sod and residue (Pearson and Ison, 1997). Frost-seeding is a form of overseeding when seed is broadcasted mid-winter on top of snow and frozen ground or in early spring aft er snowmelt (Casler et al., 1999). Once sown, the freezing and thawing of the ground helps to incorporate seed into the soil. Th is allows for better seed-to-soil contact and reduces the equipment required for planting (Kankanen et al., 2001). Both no-till drilling and broadcasting have strengths and weaknesses. Th e advantage of no-till drilling is more control over seeding depth to ensure good seed-to-soil contact (Campbell, 1985a). A disadvantage of no-till drilling is that use can be limited by steep topography. Broadcasting requires less machinery and is virtually unrestrained by topography. However, no-till drilling is considered superior to broadcasting, because more control helps ensure a proper seeding depth (Taylor et al., 1972).Several experiments that have compared broadcasting with no-till drilling found varying results. Taylor et al. (1969) discovered that drilling clover seed was important for successful establishment of red clover (Trifolium pratense L.). Th ey found that extreme moisture and temperature fl uctuations on the surface of the soil caused low establishment of broadcasted seed. Cuomo et al. (2001) found no diff erence between drilling and broadcasting in establishment across several forage legumes. Th ey learned that the main factor that determined legume establishment was the suppression of grass species. Byers and Templeton (1988) discovered that drilling produced more alfalfa (Medicago sativa L.) biomass over broadcasting, and Mueller and Chamblee (1984) found that broadcasting was more eff ective when sowing was done in late winter than in spring. In their experiment, white clover broadcasted in mid-February had greater establishment than when broadcasted in mid-March. When averaged between the two sowing dates, however, white clover (Trifolium repens L.) establishment was greater in the drilled treatments.Although sowing method should have a major impact on clover establishment, relatively few studies have compared broadcasting (frost-seeding) to no-till drilling. More information is needed about clover overseeding methods to provide guidelines to help improve establishment success. To add to this body of research, a pasture experiment was conducted from 2009 to 2011 near Blacksburg, VA. Th e primary objective of this study was to compare the eff ectiveness of broadcasting (frost-seeding) and no-till drilling for establishment of white and red clover. A secondary objective was to identify potential management variables that may help explain the succe...

Over seeding clover into permanent grasslands has many benefits, but successful establishment can be difficult as it depends on multiple interacting variables. This paper reports on a 2‐year factorial experiment conducted to evaluate how the interaction of several variables: (i) height of residual grass stubble at sowing, (ii) defoliation frequency, and (iii) fertilization with P and K affected clover seedling emergence and subsequent biomass in a permanent grass sward. In 2010, a red clover (Trifolium pratense L.) and white clover (Trifolium repens L.) mix was broadcast seeded into grass plots arranged in a split‐split plot arrangement of treatments. Clover seed sown into short grass stubble produced two times more seedlings (226 m−2) compared with sowing into tall swards (106 m−2). Frequent defoliation facilitated clover establishment, but only when seed had been sown into short grass stubble. Fertilization increased red clover yield in year 1, but this also depended on interactions with defoliation frequency and stubble height. Overall, red clover benefitted from fertilization with P and K but only during the establishing year. Fertilization also promoted a less desirable weedy species, hop clover (Trifolium campestre Schreb.), which may have had negative impacts on clover yield and white clover persistence in year 2. The results highlight the complexity of managing grass‐legume mixtures especially with respect to fertilization.

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