in order to establish the effective
vegetation models for
mudstone areas the investigation of experimental plats set at 25
km of Chi-San highway no. 184 four years ago were continuously conducted. The results of these observations were analyzed and summaried as follows: If The idea slope ratios for
vegetation were 1: 15 and 1: 2. These plots kept excellent stability of vegetation even after four-year's(1988-1991 )typhoons and storms. 2. The resrlts fo survoy on experimental plots at highway no. 182 reveal that the slope length of about 7 m contructed with one diversion ditch resulting in the least erosion,the longer slope length the more severeerosion. 3. Peat soil from indonesia improves the physic-chemical properties of the
mudstone. It has PH value of 4. 7, 90% organic matter and more than 35% humic acid was found to be very effective in promotion of the growth of the grasses. 4. The preliminary observations made on natural slopes of mudstone using seed-belt method found that vegetation continuously.Two methods were usde to establish the multi -layer vegetation: 1. one-stage vegetation(sowing seeds): After rough preparation of bare slopes,mixed seeds of woody and herbage plants were sown. One year after sowing,the growth of these plants was fairly good and primitive outline of multi-layer vegetation was seen. 2. Two-stage vegetation(transplanting):Seeds of bermudagrass(Cynodon dactylon(L. )pers. )and bahiagrass(paspalum notatum Flilgge were sown first. After vegetation coverage reached approximately 80% woody plants and wild flowets were transplanted. Morethan 90% of transplanted woody plants were survived.Establishmest of multi -layer vegetation enable the soil protected from erosion. The use of different plant types which have different depth of root systems which can hold soil tightly.These techniques have their practical value and can enhance the stability of hillslopes closed to the highways.