Killinga brevifolia Rottb. var.
leiolepis is a major perennial turf weed in Japan. In order to understand the adaptation mechanism of this species to turf conditions, the effect of cutting regimes on growth was determined by cultivating a single planting. The effects of both gap size in turf and cutting regimes on growth were determined by a cultivation experiment using the turf
Zoysia matrella. In the low-cut treatment (LCT), turf was cut weekly to a height of 1.8cm. In the highcut treatment (HCT), turf was cut biweekly to a height of 4.8cm. Neither cutting treatment (NCT) was done on the single planting in a separate experiment. The diameters of gaps made in the turf were 0cm, 5cm, 10cm and 15cm. The numbers of shoots and flower heads, growth of rhizomes, and the fresh weight of spikelets were measured.
In a single LCT planting of
K. brevifolia, the number of shoots and rhizome length of
K. brevifolia were significantly lower than those of both the HCT and NCT. HCT had little effect on the growth of
K. brevifolia (Fig. 1, Table 2). The distribution pattern of rhizomes was similar among the three cutting treatments (Fig. 3), proving that the effects of cutting were quantitative in single stands.
When
K. brevifolia was grown in the turf gaps, LCT plants produced more shoots but fewer rhizomes in total length than those of HCT (Table 3). The rhizome development pattern of
K. brevifolia in the 15cm gap exhibited a different tendency between LCT and HCT (Fig. 5), indicating that the effects of cutting were qualitative for
K. brevifolia grown in turf. The rhizome distribution in LCT was dense in the gaps, while the rhizomes extended away from the gaps in HCT. Shoot production and rhizome growth increased as the diameter of gaps in turf increased (Table 4).
These results suggest the following turf growth strategy of
K. brevifolia. Turf with frequent low cutting (e. g., fairways) allocates more biomass to shoots in order to dominate in light competition. Turf with occasional high cutting (e. g., rough) produces long rhizomes in order to seek a brighter microenvironment.
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