Plant population dynamics in subterranean clover and murex medic swards. 3. Effect of pod burial, summer grazing and autumn cultivation on emergence

Abstract

Murex medic (Medicago murex Willd.) seedling recruitment is more sensitive to soil water at the time of emergence than subterranean clover (Trifolium subterraneum L.). Murex medic pods normally lay on the soil surface. Shallow burial of pods may be beneficial when soil moisture is marginal for germination and emergence. In addition, the tightly coiled structure of murex medic pods may also act as a barrier to water uptake by the seed. Two methods of burying murex medic pods were investigated in the field: (i) trampling by sheep hooves through summer grazing; and (ii) through light cultivation in autumn. A glasshouse experiment was also conducted to examine the interaction between the length of time that the soil stays moist and pod burial for CD26 and CD53 murex medic and Dalkeith, Junee, Seaton Park and Woogenellup subterranean clover. In the glasshouse, pod burial was important for the attainment of maximum emergence in all genotypes when soil water was limiting. However, pod structure did not appear to have a limiting role in germination and emergence in murex medic. When tested in the field, pod burial by sheep trampling through summer grazing improved emergence in CD26, possibly because the smaller more open pod was more easily trampled than that of CD53. Summer grazing in CD53 and Dalkeith and autumn cultivation in all genotypes did not improve emergence; possible reasons for this are discussed so to is the role of murex medic in ley farming systems in eastern Australia.

Free-Grazing versus Enclosure Lead to an Increase in the Germination of the Leymus chinensis Seed Bank in the Hulunbuir Grassland

“…In the free grazing area, due to the influence of grazing livestock, the seeds of Leymus chinensis with smaller seeds are more likely to be buried, so there will be a higher germination rate. This scenario is more consistent with the research results of Blumenthal and Ison (1996) [41]. However, in terms of the trade-off between sexual reproduction and asexual reproduction, although Qing (2002)'s research results in 1999 showed that the seed-bearing percentage in the free-grazing area was much higher than that in the enclosed area and that the ratio of healthy seeds to reproductive branches was also higher in the free-grazing area than that in the enclosed area, the number of ears in the enclosed area was lower than that in the free-grazing area.…”

Stocking rate effects on metabolizable energy intake and grazing behaviour of Tan sheep in steppe grassland on the Loess Plateau of Northwest China

“…Defoliation also promotes tillering of grasses (Hodgson 1990), stimulates the regrowth of herbage (Leriche et al 2001) and indirectly impacts on underground parts of plants and soil properties (Ford & Grace 1998;Greenwood & Hutchinson 1998). Treading by livestock buries herbage seed and thereby promotes imbibition and germination of seed (Blumenthal & Ison 1996). Treading also fragments plant litter and therefore accelerates its decomposition (Zacheis et al 2001).…”

Germination success under different treatments and pod sowing depths in six legume species present in olive groves

“…Siles et al (2016) have shown that the effect of burial is species-specific. Blumenthal & Ison (1996) found that marginal humidity conditions in the shallow sowing of pods of Medicago murex could be beneficial for the germination and emergence of seedlings, and that this effect may vary in terms of the environmental stress to which seeds are subjected. Our study shows that the effect of burial varies in terms of the species and pod traits (i.e.…”