**5. Discussion**

The AHP method was applied in this study to identify, correlate, weigh, and rank different landslide parameters that determine slope susceptibility. Using the systematic analysis of a pairwise comparison matrix of a list of the conditioning factors by expert's opinion scores between one and nine indicates the relative importance that was used. The susceptibility map helped determine high-risk, landslide susceptible areas for the mitigation process. The output map of the landslide susceptibility model was evaluated qualitatively, which is essential in selecting the most suitable site to carry out the landslide mitigation experiment. Applying the AHP approach, very low susceptibility

areas were 20.65%, 20.18% low, 20.37% moderate, 19.45% high, and 19.35% very highly susceptible areas.

From the AHP susceptibility map, a hydroseeding experiment was carried out on the high-risk visibly sliding slope, with the result revealing that hydroseeding has grea<sup>t</sup> potential on degraded terrains in a similar environment. Results also showed that the grasses thrived more during rainfall season than dry season with daily watering. The results of the vegetation root system appear to show that vegetation has the best potential for long-term slope stabilization. Comparing the development of this study with other researchers that successfully carried out a similar experiment in a laboratory using rainfall simulations, the experimental results are very similar with natural precipitation and daily watering. Improved knowledge on this research is equally expected to support and enhance the selection of hydroseeding components and improve the soil nutrient and native species in future restoration projects.

Several authors have argued that climatic conditions and soil types are the main factors limiting the vegetation reinforcement of soil, especially in semiarid environments, resulting in low vegetation cover and distorted roots [109]. Hence, this experiment went through rainy and dry seasons and different soil types to prove the effectiveness of the selected seed with good results.

According to Garcia-Palacios et al. [110], vegetation covering more than 50% of semiarid terrain requires no further mitigation to prevent landslide or soil erosion. In this research, the vegetation ground cover for ryegrass and signal grass was less than 50% in August. Ryegrass was also less than 40% in September, with both plants maintaining soil stability. Risse et al. [111] noted that the rate of soil loss was about 10 to 20 times higher in construction sites than in agricultural lands. Moreover, Wang et al. [112] stated that several studies have revealed that soil properties such as moisture content and nutrients could affect their root morphology as vegetation matures. Thus, in our experiment, the vegetation root system increased with time, though evidence of nutrient loss could be seen from the plant leaves.
