Abstract
Germinating behavior and adhering strength of tall fescue seed (Festuca arundinacea Schreb., variety "Kenkucky 31") under various soil moistures of four soil types were investigated to evaluate the favorable moisture content and hardness of soil for attaining good establishment of seed. Yellow soil (Takanoo paddy field soil) and three kind of Kuroboku soil(Takanoo non-volcanic ash soil, Kawatabi and Nishinasuno volcanic ash soil) were used in the experiment. Yellow soil was arranged 7 levels of soil moisture ranging from 40 to 90 percent of water holding capacity at 5 or 10 degree increments, and each Kuroboku soil was 6 levels from 55 to 90 percent, respectively. The seeds were allowed to germinate under constant temperature of 25℃. The adhering strength of coleorhiza hairs which is defined as maximum tensile load to pull out a seed from soil surface, was measured by using rising seed at the soil moisture treatment in which the maximum rising percentage was obtained. The germinating behaviors were classified into three types ; Type I (lying type), Type II (rising type) and Type III (exposed root type). 1) The maximum germination percentage of type II, 80%,was obtained at 40 percent soil moisture content for paddy field soil ; the average of adhering strength indicated 3 g. In the Kuroboku soils, the maximum germination percentage of type II, about 40%, was obtained in the 85 percent treatment, and the adhering strength ranged 0.4-0.8 g (Fig. 1, Tables 3 and 5). 2) When the hardness values of Kuroboku soil surface measured by the silk-needle method rose up greater than 5 g, germinating behavior of type III increased extremely. On the contrary, type II in paddy field soil was more dominant than type III in harder than 10 g conditions (Fig. 2). 3) In all soils, type I was observed under the condition that soil surface hardness were lower than 3 g (Fig. 2). 4) There were evident differences between paddy field soil and Kuroboku soil as regards the percentage of germinating behavior type which was governed by the adherring strength of coleorhiza hairs.
