VETIVER GRASS AS EROSION AND LAND PRODUCTIVITY CONTROL; Experience At lratunseluna Catchment Area Central Java
Oleh: SYAHRUL DONIE, R. SUDRADJAT
Journal Volume II No, 3, 1996
Download file: Vetiver_Grass_as_Erosion_and_Land_Productivity_Control
The use ofvetiver as erosion and land productivity control was investigated in Boyolali (CentralJava)from 1990 to 1992. The method used are:
1. Grass barrier with Vetiveria zizalliaides
2. Grass barrier with Setaria spacelata
3. Ridge terrace with Setaria spacelata
Control : Existing soil conservation management (outward stooping terrace without grass barrier)
Those treatments used as a strip cropping along border line of 1 ,500 m2 plot area for each treatment. Zea mays. Sesamme indicum and nut bean were planted for two harvesting periods within three years in plot area. In addition.
Mucuna escherichinensis also planted as cover crop during April- June. The result showed that the use of vetiver as grass barrier could reduce erosion of 72.7% and stream coefficient of 12.5 % compared to control. Moreover. Zea mays production was increased by 104.7 % at harvesting period 1 and 122 % at harvesting period II. as for Sesamme indicum was increased by 89.3 % and nut bean production by 142.9 %. Production ofvetiver grass was 2.278 kg/ha and Mucuna 1,534.4 kg/ha. they were the highest compared to other treatments.
Erosion control through vegetation method offer three advantages. ie : Easiness. cheap. produce grass or other products. Vetiver as grass barrier own deep rooting, densely leaves as cattle feed and well known as best for soil conservation
The aim of the research is to investigate the ability of vetiver for erosion and land production control compared to Setaria, combination of ridge terrace with Setaria and existing soil conservation method (outward slooping terrace without grass barrier).
The location was Boyolali (Central Java) at Jratunseluna catchment area that have Grumosol soil type with properties: low permeability and infiltration, high erosion, low organic materials, solum width less than 100 cm. This area owns four months dry season and eight months wet season with the highest raining day of 1 13 mm.
The method used consists of three soil conservation treatments and one control, ie :
- Treatment 1 (PI) : Grass barrier with Vetivera zizaniaides
- Treatment 2 (P2) : Grass barrier with Setaria space lata
- Treatment 3 (P3) : Ridge terrace planted with Setaria spacelata (Terrace width 0.5 m, height 0.3 m)
- Control (P4) : Existing farm management (without grass barrier and used outward slooping terrace)
Each treatment and control covered plot area of 1,000 – 1,500 m2, spread over three blocks with three replications. Plot area were planted for two harvesting periods with the following patterns:
- Harvesting period (HP) I (November – February) : Zea mays + Sesamme indicum (wijen) (ship cropping with 0.5 m distance)
- Harvesting period (HP) II (March – June) : Zea mays + Arachis hypogea (nut bean) ship cropping with 0.25 m distance)
- Harvesting period (HP) III (April – June): Mucuna escherichinensis as cover crop
These cultivation patterns were conducted for three years as replication. Parameter observation used were:
- Erosion and run off: Using erosion plot of 4 x 22 m and sedimen collector. Data is collected every raining day.
Erosion calculation using USLE method.
- Plant production : Data collected every two months for grass and at the end of harvesting period for plants. Data collections were wet weight for grass and plants.
The data are analysed every year with three years plant cultivation.
III. RESULT AND DISCUSSION
A. P Factor and Stream Coefficient
CP factor and stream coefficient both are parameters to determine the effectivity of erosion control and run off for each treatment. Calculation of CP factor, stream coefficient and its reduction to control (P4) are presented in table I.
Table I shows that the highest reduction of CP was given by vetiver grass barrier (PI) followed by combination of ridge terrace and Setaria (P3) and Setaria alone (P2). The highest reduction of stream coefficient obtained by P3 followed by PI and P2. These data show that vetiver grass barrier suceessfully reduce erosion as it is indicated by the the lowest CP and reduce run off moderately as well. The fact that vetiver gave fast and stabile barrier along the contour, lowering stream flow and precipitating sediment, hence supplying nutrients for young vetiver plant. At year I and 2 the lowest stream coefficient given by P3 due to the major rate of ridge terrace, but at year 3, the vetiver grass barrier take over the control. Table 2 presents plant production at harvesting period I and II.
B. Plant Production
Productions of treatment plants are presented in table 2 and table 3.
Table 2 shows clearly that all treatments gave higher plant productions (Zea mays, Sesamme, nut bean) every harvesting period (HP) and every year. At HP I, vetiver leading in increasing plant productions than other treatments. But in HP II there was no substintially different among other three treatments although still markedly higher than control. Considering that a lesser rain drop in HP II and more dry soil surrounding vetiver environment than Setaria, it is likely due to the influence of soil moisture affecting nutrients uptake. Postulately vetiver transpired soil water higher than Setaria due to deeper rooting.
Table 3 shows that grass and Mucuna produced by vetiver was substantially higher compared to other treatments although the growth was slower during the first year.
- Vetiver as grass barrier could effectively reduce erosion, stream coefficient and produced highly Mucuna and grass.
- Vetiver reduces CP factor of 72.7 % and stream coefficient of 12.5 % to control.
- During three years observations, vetiver prooved successfully increased Zea mays production of 104.7 % at harvesting period (HP) I and 122 % at HP II. Sesamme increased 89.2 % at HP I and nut bean 142.9 % at HP II. Production of grass of 2,278 kg/ha and Mucuna 1,534.4 kg/ha. These values are the highest compared to other treatments.
ANONIMUS. 1990. Laporan Pelaksanaan Studi Pengelolaan Tanah Dangkai dan Marjinai Tahun 1988/1989. Kerjasama an tara Proyek Penelitian Penyelamatan Hutan Tanah dan Air (P3HT A) dengan Balai Teknologi Pengelolaan Daerah Aliran Sungai (BTPDAS).
ANONIMUS. 1992. Laporan Pelaksanaan Penelitian Pengelolaan Tanah dangkal dan Marjinal Tahun 1989/1990 – 199111992. Kerjasama antara Proyek Penelitian Penyelamatan Hutan Tanah dan Air (P3HT A) dengan Balai Teknologi Pengelolaan Pengelolaan Daerah Aliran Sungai (BTPDAS).
TROUNG, P. and WAL SCA TTINA. 1990. Vetiver – The Hedge Against Soil Erosion. Australian Journal of Soil and Water Conservation. Vol. 3 No. 3, August, 1990.Page 16 – 18.
TROUNG, P. Report on The International Vetiver Grass Field Workshop, Kuala Lumpur. Australian Journal of Soil and Water Conservation. Vol. 6 No.1, February, 1993.