Abstract
The purpose of the research is to identify the optimal seeding quantity of Lespedeza cyrtobotrya and Indigofera pseudo-tinctoria as leguminous woody plants for the cut-slope revegetation. To investigate the coverage ratio and appearance frequency, we divided Lespedeza cyrtobotrya and Indigofera pseudo-tinctoria into five treatment groups with various quantities of $0.0g/m^2$, $1.0g/m^2$, $2.4g/m^2$, $3.8g/m^2$, and $5.2g/m^2$. For each treatment group, we mixed the identical quantities of herbaceous flowers (Lotus corniculatus var. japonicus, Dianthus sinensis, Aster yomena and Pennisetum alopecuroides) seeds and cool-season turfgrasses (Festuca arundinacea and Poa pratensis) seeds. In this result, as the seeding quantity of Lespedeza cyrtobotrya and Indigofera pseudo-tinctoria increased in the spray, the coverage ratio for leguminous woody plants appeared to increase whereas the coverage ratio decreased in herbaceous flowers and cool-season turfgrasses. However, when the seeding quantity of Lespedeza cyrtobotrya and Indigofera pseudo-tinctoria exceeded $3.8g/m^2$ in the spray, the coverage ratio of leguminous woody plants rather decreased compared to four treatment groups less than $3.8g/m^2$ seeding ratio. Based on the longitudinal data of coverage ratio in five treatment groups, we observed the gradual process of a short-term succession in which the dominant species shifted in the following order: First, cool-season turfgrasses; Second, herbaceous flowers; Third, leguminous woody plants. Comparing the appearance frequency of Lespedeza cyrtobotrya and Indigofera pseudo-tinctoria, Lespedeza cyrtobotrya appeared more frequent in 2014 whereas Indigofera pseudo-tinctoria appeared to be relatively more frequent in 2015. As a result, Indigofera pseudo-tinctoria was discovered to be a dominant species among woody plants. In this study, we observed that the optimal seeding quantity of Lespedeza cyrtobotrya and Indigofera pseudo-tinctoria was $2.4g/m^2{\sim}3.8g/m^2$. Moreover, the coverage ratio of 29.1%~35.4% and appearance frequency of 4.6plants~5.8plants were found in the condition of optimal seeding quantity.