Effects of Sward Height at the End of Each Rotational Grazing Period on the Number of Ears in Grazed Japanese Lawngrass (Zoysia japonica Steud.) Pastures

摘要

As a solution for the utilization of abandoned arable land, Japanese lawngrass (JL) can be used for grazing. To utilize JL for "integrated grazing system for scattered small pasture", the management practices for rotational grazing on JL pasture have to be investigated in detail. We investigated the number of ears in the two pastures with sward height of 5 cm (LS pasture) and 10 cm (HS pasture) at the end of each rotational grazing period. The number of ears at the start of the first grazing of the year at May in LS pasture was more than that in HS pasture. It was suggested that low sward height relate to the decrease in the reserved nutrients for floral differentiation and ear emergence, because the number of ears at the start of the first grazing of the year was affected by the reserved nutrients in the previous year. The number of ears at the start of the second grazing at July in HS pasture was more than that in LS pasture significantly and the ears observed at the start of the second grazing might have emerged after the first grazing. These suggest that the number of young panicles which was not eaten by cattle was more in HS pasture than LS pasture. For the establishment of JL pasture, high sward height in spring might enable us to enlarge JL coverage. In the established pasture, low sward height might enable us to suppress the nutrients and energy consumption by earing.