The first evaluation and identification conference on the aplication of vetiver system for highway embankment protection was held in Zhejiang Province of east China on 8-12 November 2000. The conference was co-organized by China Vetiver Network, The Communication Bureau of Zhejiang Province, The Highway Administration Division of Zhejiang Province, the Communication Bureau of Lishui Prefecture, The Highway Management Department of Lishui Prefecture, etc. Scientists and experts came from Highway Bureau of China Communication Ministry, the Highway Institute of China Communication Ministry, The Communication Institute of Zhejiang Province, The Water Conservation and Hydro-electricity Design Academy of Zhejiang Province. Altogether 50 participants attended the conference, including provincial institution directors, county chief, and highway company managers. The participants came from almost all administrative levels, from national to provincial, prefecture, county, and even township. The conference is characterized by the combination of identification and evaluation, research, application, and extension, in order that engineers in Zhejiang Province can familiar with and use vetiver system (VS) more rapidly and widely.
In 1998 engineers from Zhejiang highway institutions learnt vetiver grass technology (VGT) from the article in highway journals, which was co-prepared by China Vetiver Network, The Highway Administrative Bureau of Jiangsu Province, and The Communication Survey and Design Academy of Jiangsu Province. To obtain more knowledge, they visited several demonstration sites and nurseries in Fujian Province, and studied their experience. They found that with vetiver systems the highway embankment can be well fixed with much less money than using traditional hard measures. Besides, vetiver systems can protect the environment and keep the slope green in a very short time, which became very important because nowadays people require high quality environment than ever before. In 1999 a project titled "Application Research on the Using of Vetiver in Highway Construction in Zhejiang Province" was granted by the provincial communication bureau. The project was prepared and co-implemented by engineers and directors from different institutions from the province, the prefecture, and the county to which the project was located. Almost all of the provincial highway institutions were involved, including the Highway Bureau, Highway Association, Communication Science Institute. The project was implemented very seriously from the very begining. They signed project contract, prepared implementation plan, planting specification, and time table. During the whole project period they kept observation, analysis, and recording, and organized several workshops to deal with problems and train engineers. When the project was finished they organized the evaluation conference. Therefore, the project is the first one launched by highway institution themselves, to which so many engineers were involved. The project was carried out so seriously in China that no other projects can match with, although some similar projects were implemented several years ago in other provinces.
The participants visited the nursery near Hangzhou and the
demonstrations in Lishui City and Jingning County of Lishui
Prefecture in southern part
of the province just before the conference.
The project started vetiver planting in early 1999. They got healthy planting materials in spring from Pingtan Island of Fujian Province based on careful observation and selection to almost all nurseries in Fujian Province. During the observation they realized that the quality of planting materials were essential to their project. With the planting materials the first thing to be considered was to establish a high quality nursery. They selected a flat land with irrigation facilities and sandy loam texture for reproduction purpose in XiaoShan, just near Hangzhou. The land was generated by enclosing tideland 13 years ago, planted with cotton for some years. Because ground water table was high about one meter, they prepared standard ridges and high beds. Before planting, they prepared specifications in order to produce high quality tillers. The field work included:
1) Workers were divided into several groups to form an assembly line;
2) Before tillage diluted human manure was applied. But the quantity should be limited otherwise the grass would be damaged;
3) Clayey soil was collected and sieved to prepare clay paste and then filled into containers transported to the field. The roots were dipped withthe paste just before planting;
4) Ditches were prepare for 20 cm deep, and tillers were
planted and the soil around the plants should be compacted in
order that the soil can well
connect the roots.
5) Watering the plants just after the planting.
6) The plants start to re-greening and growth on the 7th day since planting.
7) During the growing season compound fertilizers was applied.
8) First pruning was implemented with mechanical saw on 25 July at the height of 60 cm above ground surface when the grass was 170 cm high. Ten days later the cut grass was 110 cm high, while the un-cut grass was 180 cm, i.e. the cut grass increased 50 cm, while the un-cut grass increased only 10 cm. The 2nd cut was on 1st September.
9) During the dry season the grass was watered in the very
early morning at from 4 to 8 o'clock.
General speaking, the nursery was extremely carefully managed, and the tillers were in excellent quality. The clump has a strong root system distributed in the soil around 140 cm in diameter, and the grass was 118 m high when the participants visiting. There were 80 -120 thick tillers per clump. Almost all managing activities were carefully recorded in addition to weather condition. To produce more tillers they planted the grass during different time, almost the whole growing season.
The project sites was situated at southern part of Zhejiang Province, bordering Fujian Province. Because it was covered by mountains most of the sections of highway had to contructed with cuts and fills, which caused un-stsbility of not only the road embankments but also the slopes along the roads. The annuanl average temperature is 18.6C with mean rain fall of 1454.1 mm. The soil consisted of about 80% sands and silts, from 1.0 mm to 0.01 mm, in addition to gravels over 1 mm. The soil contains almost no nitrogen. As most of the rain fall concentrated in summer and therefore caused serious erosion
The participants visited the demonstrations in the morning of 11 November. The demonstrations were located in two places: the national highway NO. 330 in Lishui City and provincial highway NO. 52 in Jingning County. All the demonstration sites were distributed in mountainous area. Although the absolute elevation was not high, around 100 to 200 m above sea level, the relative elevation was great with typical mountainous landform characteristics. Soil erosion has been very serious. The highway administrations had had to repair the road frequently. In April 1999 vetiver was introduced from Pingtan Island and planted on 4 sections along the national highway NO. 330, in which 2 were cuts and 2 were fills. Six months since planting the grass reached 200 cm height and with 21 tillers per clump in maximum. The average height was 150 cm. A fence was bacically formed and the roots systems were connected each other which was around 80 cm deep. The thick root reached 2.5 mm in diameter. The slope was generally fixed. When the participants visited there the grass was 180 cm high in average.
Based on the success on national highway NO. 330, VS was
introduced to Provincial Highway NO. 52 in May 2000. The soil was
extremely soft during
planting. When a person stand on the ground the soil could bury
the ankles. Two sides on one section of highway were planted with
vetiver. The survival
rate was almost 100%. Later, in September vetiver grass was
planted on the extended section with survival rate for 85%.
Altogether around 26 385 m2 was planted at two highways. Vetiver grew better on fills than on cuts because the soil on the fills usually contain much SOIL, while the cuts contain semi-weathered parent materials which had little nutrients and usually compacted. As a result, careful management (watering and fertilizer) should be taken in the first few months since planting.
Another problem is that vetiver grass is different from other grass. It should be closely planted along contour, while the apace between rows can be larger, two meters for example. Most engineers are accustomed to plant grasses evenly covered the ground. They wanted to reduce the space between rows and increase the space between clumps. As the result, the sediments could not stopped and gullies formed. This is the key point to be emphasized when we introduce the grass to the engineers.
In the afternoon on 11 November 2000, a meeting was organized by China Vetiver Network. At first the director of the project reported the entire activities of the project to all the participants. And then he aswered the questions required by the participants. It was estimated that there was altogether 26 385 m2 slopes planted with vetiver on national highway NO.330 and Provincial highway NO.52, which costed 220 000 Yuan RMB including demonstration and research, i.e.8.3 Yuan RMB/M2, while it would use 1 583 000 Yuan RMB if use hard measure. It saved 1 363 000 Yuan RMB. Then an evaluation committee consisting of 11 experts checked up all project documents including:
1) the project contract,
2) project design,
3) mid-project evaluation and summary report,
4) final project report,
5) soil background analysis,
6) customers' evaluation reports.
After that the experts had a comprehensive evaluation on the effect of vetiver hedges on highway protection, enviroment, and economic benefit . They had a hot discussion and prepared a summary report which approved the success of the project and indicated the shortage and proposed the suggestions for their further improvement. The experts realized that the project contractors paid emphasis on the quality and the combination experiment, demonstration, and extension. Within the project period they organized several different workshops on the seedling production, fence establishment, and extension. They 'participated in the 'Conference on Vetiver Bio-Engineering Technology for Erosion and Sediment Control and Civil Construction Stabilisation' held in Nanchang of China in October 1999 and introduced the conference to the engineers. The project generated wide interests among not only project members but also non-project members through out the province. It is assured that with high quality planting materials produced by the project, accompanied by vetiver technology dissemination VS could be extend more rapidly through out the province which has a territory for over 100 000 km2 most of which is covered by mountains or hills.