Sowing Method Effects on Clover Establishment into Permanent Pasture

Abstract

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...

Conditions that favor clover establishment in permanent grass swards

“…The data suggest that red clover plants that were established in the short stubble vegetation in 2010 were still the primary contributors to yield the following year. This result confirms the idea that over seeding clover into short residual stubble is a critical element for successful establishment and to ensure subsequent contribution to yield (Schlueter and Tracy ). The response of red clover to the higher defoliation frequency was surprising though as several studies have shown that growth can be negatively affected by frequent defoliation (Sheldrick et al .…”

“…Successful clover establishment in grass swards clearly depended on reducing grass competition at sowing and frequent defoliation. While not a surprising result, our data indicate that clover establishment is contingent on both processes (Schlueter and Tracy 2012). In other words, frequent defoliation alone probably will not improve clover establishment unless the initial grass competition is greatly reduced at sowing and vice versa.…”

“…), but questions still remain about how many of these variables interact to influence establishment. The experiment reported in this paper resulted from a grazing study that evaluated different sowing methods on clover establishment in Virginia, USA (Schlueter and Tracy ). Different sowing methods did not affect clover establishment in this study, but the grass stubble height to which clover was overseeded was much more important at predicting clover biomass.…”

Evaluation of Perennial Warm‐Season Grass Mixtures Managed for Grazing or Biomass Production

“…like the WSG pastures previous to conversion and had been used for grazing experiments as described by Schlueter and Tracy (2012). A hydraulic soil corer (Giddings Machine Company) was used to collect soil samples 6.35 cm in diameter by 40 cm.…”

“…The CSG pastures were dominated by tall fescue and clovers (Trifolium spp.) like the WSG pastures previous to conversion and had been used for grazing experiments as described by Schlueter and Tracy (2012). Soils were dried at 105°C until a constant weight was reached.…”