1.3 Conditions regarding the use of data documented through WOCAT

When were the data compiled (in the field)?

03/09/1999

The compiler and key resource person(s) accept the conditions regarding the use of data documented through WOCAT:

Yes

2.1 Short description of the Technology

Definition of the Technology:

Contour lines of vetiver grass planted within fields of sugar cane, on stream banks and roadsides, to act as ‘hedges against erosion’.

2.2 Detailed description of the Technology

Description:

This example of vetiver grass barriers comes from a commercial farm in Kwa-Zulu Natal, South Africa, where sugar cane is grown on a large scale under a rainfall regime of around 1,000 mm per year. Vetiver grass (Vetiveria zizanioides), which had been growing naturally on the farm for years in isolated clumps, began to be used in 1989 to form vegetative hedges along the contour.
The purpose of these hedges is to protect the land from surface erosion by creating semi-permeable barriers, allowing excess runoff to filter through but holding back sediment. Infiltration is thus increased and moisture conserved in-situ. Although sugar cane in itself protects the soil quite well when the canopy is closed, after harvest on the moderate to steep slopes (10% to >30%) and erodible soils of the north coast of Kwa-Zulu Natal, extra protection is required. The vetiver system is supplemented by other soil conservation measures such as strip cropping, terraces, mulching and minimum tillage – all of which are used to some extent on this farm. Vetiver also helps by permanently marking the contour line, which then guides land preparation. In common with other vegetative barriers, vetiver lines lead to the formation of terraces over time, through the effect of tillage and water erosion between the strips.
Vetiver clumps are dug up and separated into slips (tillers), cut to a length of 10 cm and then planted 10–15 cm apart along the contour, also by stream banks, and by roadsides, just before the rains. This ensures good establishment. Single lines are used in this farm, though double lines are more effective at creating a hedge, and are the normal recommendation. Work starts at the top of the slope, and continues downwards. The cross-slope grass hedges are sited at 5 m vertical intervals on slopes of more than 10%, in lines about 200 m long. The cost of vetiver grass planting depends very much on slope (and thus the number of lines to be planted), availability of materials and labour.
Maintenance is very important, as vetiver often requires ‘gapping-up’ to keep the barrier dense, and it needs also to be cut back before the dry season to prevent it burning. The cut material can be used for mulching. Vetiver is poorly palatable, and therefore not useful as fodder. The maximum height of a vetiver hedge is kept down to approximately 50 cm. This minimises shading and competition, keeps the fire risk low, increases tillering (for production of vegetative splits) and ensures adequate density.

2.3 Photos of the Technology

2.5 Country/ region/ locations where the Technology has been applied and which are covered by this assessment

2.6 Date of implementation

If precise year is not known, indicate approximate date:

• less than 10 years ago (recently)

2.7 Introduction of the Technology

Specify how the Technology was introduced:

• during experiments/ research

Comments (type of project, etc.):

The grass originally came to this country from Mauritius.

3.2 Current land use type(s) where the Technology is applied

Comments:

Major land use problems (compiler’s opinion): The steep topography and shallow soils limit the types of land use possible e.g.. perennial grass cover (sugarcane or grazing) or commercial timber production. Annual cropping is not possible without major alteration to the landscape e.g. terracing.

3.3 Further information about land use

Water supply for the land on which the Technology is applied:

• rainfed

Number of growing seasons per year:

• 1

Specify:

Longest growing period in days: 200

Longest growing period from month to month: Oct - April

3.5 Spread of the Technology

Specify the spread of the Technology:

• evenly spread over an area

If the Technology is evenly spread over an area, indicate approximate area covered:

• 1-10 km2

Comments:

Total area covered by the SLM Technology is 8 m2.

The vetiver system has been applied on my own properties. Neighbouring farms have adopted other methods of conserving the soil. i.e. vegetative, agronomic and structural in various combinations (= farm)

3.6 SLM measures comprising the Technology

Comments:

Main measures: vegetative measures

Secondary measures: agronomic measures, structural measures, management measures

Specification of other vegetative measures: grass strip as hedges

Type of agronomic measures: mulching, minimum tillage, contour ridging

3.7 Main types of land degradation addressed by the Technology

Comments:

Main type of degradation addressed: Wt: loss of topsoil / surface erosion, Wg: gully erosion / gullying, Et: loss of topsoil, Hg: change in groundwater / aquifer level

3.8 Prevention, reduction, or restoration of land degradation

Specify the goal of the Technology with regard to land degradation:

• reduce land degradation
• restore/ rehabilitate severely degraded land

Comments:

Main goals: mitigation / reduction of land degradation

Secondary goals: rehabilitation / reclamation of denuded land

4.1 Technical drawing of the Technology

4.2 Technical specifications/ explanations of technical drawing

Vetiver grass is planted as a vegetative barrier (hedge), on the contour at 5 metre vertical intervals within fields of sugarcane.

Location: Lower Tugela district. KwaZulu/Natal

Technical knowledge required for field staff / advisors: low

Technical knowledge required for land users: low

Main technical functions: control of dispersed runoff: impede / retard

Secondary technical functions: control of concentrated runoff: impede / retard, increase / maintain water stored in soil

Mulching
Material/ species: Sugarcane
Remarks: Full ground cover

Minimum tillage
Material/ species: Chemical crop eradication

Contour ridging
Material/ species: Planting lines ridged on contour

Vegetative measure: contour
Vegetative material: G : grass
Vertical interval between rows / strips / blocks (m): 5
Spacing between rows / strips / blocks (m): 2
Vertical interval within rows / strips / blocks (m): 0
Width within rows / strips / blocks (m): 0.5

Vegetative measure: Vegetative material: G : grass

Vegetative measure: Vegetative material: G : grass

Vegetative measure: Vegetative material: G : grass

Grass species: Vetiver grass

Slope (which determines the spacing indicated above): 20.00%

If the original slope has changed as a result of the Technology, the slope today is (see figure below): 20.00%

Gradient along the rows / strips: 0.00%

Other type of management: Cane is planted on suitability (slope, soil depth)

4.3 General information regarding the calculation of inputs and costs

other/ national currency (specify):

rand

Indicate exchange rate from USD to local currency (if relevant): 1 USD =:

6.00

4.4 Establishment activities

	Activity	Type of measure	Timing
1.	Plant with fertilizer & water	Vegetative	Rainy season (Sept - Mrch)
2.	Weed & gap plant	Vegetative
3.	Cut back to promote tillering	Vegetative
4.	Crop gradication	Management	Nov-Jan
5.	Ridging of planting furrows	Management	+- 1-2 months before
6.	Planting of sugarcane - fertiliser in furrow	Management
7.	Top dress fertiliser	Management	9 week after planting
8.	Herbicide application	Management	Anytime necessary after planting

4.5 Costs and inputs needed for establishment

Comments:

Duration of establishment phase: 24 month(s)

4.6 Maintenance/ recurrent activities

	Activity	Type of measure	Timing/ frequency
1.	minimum tillage	Agronomic	mulching at harvest
2.	minimum tillage	Agronomic
3.	mulching at harvest	Agronomic	April-Dec / Every year
4.	Weed	Vegetative	/3 times
5.	Gap plant	Vegetative	/Once
6.	Weed	Vegetative	/When required
7.	Spray for creeper grasses	Vegetative	/When required
8.	Plaint unwanted trees etc.	Vegetative	/When required
9.	Harvest sugarcane	Management	/ Annual
10.	Trash management (mulch spreading)	Management	After harvest completed / Annual
11.	Fertiliser application	Management	1-2 months after harvest / Annual
12.	Herbicide application	Management	Required / Annual
13.	Hand weeding	Management	/ Annual & when required

4.7 Costs and inputs needed for maintenance/ recurrent activities (per year)

Comments:

Machinery/ tools: 1 hoe

1) Labour,
2) Transport,
3) Price of grass,
4) Fertiliser,
5) Equipment

4.8 Most important factors affecting the costs

Describe the most determinate factors affecting the costs:

1) Labour,
2) Transport from nursery to field,
3) The steeper the gradient the more contour lines of vetiver grass will be used,
4) Fertiliser

5.1 Climate

5.2 Topography

5.3 Soils

5.6 Characteristics of land users applying the Technology

5.7 Average area of land owned or leased by land users applying the Technology

5.8 Land ownership, land use rights, and water use rights

Land ownership:

• individual, not titled

Land use rights:

• individual

6.1 On-site impacts the Technology has shown

Socio-economic impacts

Production

Income and costs

Socio-cultural impacts

Ecological impacts

Water cycle/ runoff

Soil

Climate and disaster risk reduction

6.2 Off-site impacts the Technology has shown

6.4 Cost-benefit analysis

How do the benefits compare with the establishment costs (from land users’ perspective)?

How do the benefits compare with the maintenance/ recurrent costs (from land users' perspective)?

6.5 Adoption of the Technology

Comments:

100% of land user families have adopted the Technology without any external material support

3 land user families have adopted the Technology without any external material support

Comments on spontaneous adoption: estimates

There is a little trend towards spontaneous adoption of the Technology

Comments on adoption trend: Some local growers are experimenting with the vetiver system or with vetiver grass used in other applications (gullies, road embankments, etc.)

6.7 Strengths/ advantages/ opportunities of the Technology

Strengths/ advantages/ opportunities in the land user’s view
The author is the land user

Strengths/ advantages/ opportunities in the compiler’s or other key resource person’s view
When planted correctly, vetiver forms a dense, permanent hedge which retains soil and water so increases crop yield How can they be sustained / enhanced? Make sure there are no gaps between slips in order to maintain a dense vegetative barrier.
It has a strong fibrous root system that penetrates and binds the soil to a depth of up to 3 meters and can withstand the effects of tunnelling and cracking. Its many uses e.g.. Thatching, mulching etc.
Vetiver grass seed is sterile so it doesn’t spread.
Not very competitive to crops growing alongside.
The cut material can be used for mulching and has multiple secondary uses (thatching, basket making, etc). Once established it can withstand periods of drought and waterlogging. It is also resistant to grazing and to most pests and diseases. Adaptability: can be planted in various environments and grows well in most soil types. Depending on the availability of planting materials and the spacing adopted, can be relatively cheap and easy to establish and – once well established – vetiver requires minimal maintenance.

6.8 Weaknesses/ disadvantages/ risks of the Technology and ways of overcoming them

Weaknesses/ disadvantages/ risks in the land user’s view	How can they be overcome?
The author is the land user

Weaknesses/ disadvantages/ risks in the compiler’s or other key resource person’s view	How can they be overcome?
Sugarcane residue is often blown against the hedges & this can form a thick blanket thus preventing ratooning of crop	Strategic/controlled burning at end of growing season or trimming back
The grass burns very easily when mature, due to its density	Keep chemicals off vetiver.
Susceptible to certain chemicals used in sugar cane	Establish own nursery.
Planting material expensive to buy: therefore costs increase considerably unless farmer has own nursery
Takes time to plant a large area (in this case 2.5 ha per year).