Van Rensburg Leon
有助于对技术进行记录/评估的项目名称（如相关）Book project: where the land is greener - Case Studies and Analysis of Soil and Water Conservation Initiatives Worldwide (where the land is greener)
有助于对技术进行记录/评估的项目名称（如相关）Sustainable Land Management Practices of South Africa (SLM South Africa)
Eradication of invasive species and revegetation of degraded rangelands by different treatments, including oversowing with grass seed mixture, supplementing with lime, cattle dung, and "brush packing" (laid out branches).
A research investigation was undertaken in an area of degraded communal rangeland, which had been invaded by an alien tree species (Acacia mearnsii – black wattle). Competition from the water-demanding A. mearnsii, combined with overgrazing, had resulted in an almost total absence of palatable grasses. All that was left were a few patches of star grass (or ‘bermuda grass’: Cynodon dactylon). Prior to the research, discussions were held between personnel of the ‘Working for Water’ programme of the South African government and community members.
The purpose of the trials was to determine how best to eradicate the invasive trees and revegetate the rangeland. The restoration area was not fenced off and was thus open to grazing. The trials comprised five treatments, with three replicates each, on plots of 10 m by 20 m. In all treatments the A. mearnsii was eradicated manually, and chemical biocide applied to the stumps to prevent regrowth. Lime and grass seed (of palatable species) were applied to the loosened surface and covered with soil. The five treatments were:
(A) oversowing with grass seed mixture, supplementing of dolomitic lime, cattle dung, and ‘brush packing’ (see below for explanation of term);
(B) oversowing with grass seed mixture and supplementing with cattle dung;
(C) oversowing with grass seed mixture and supplementing with dolomitic lime;
(D) oversowing with grass seed mixture and brush packing;
(E) oversowing with grass seed mixture only.
In addition stone lines were laid out along the contour, between plots. The ‘brush packing’, referred to in treatments A and D comprised branches laid out in strips across the slope to retard runoff, trap soil, improve the micro-climate for establishing grass seedlings and protect the young plants from browsing by animals. The results showed treatment A to be the most effective in restoring the productive and protective function of the rangeland. From the trials, the estimated costs of applying the best technology would be US$ 230 per hectare. The key constraints for successful adoption however are not just technical, but include: (1) the need to protect the area from grazing and trampling by animals during the establishment period; (2) stopping removal of brushwood for firewood; and (3) the need for community agreement on initial protection and subsequent sustainable utilisation of the restored range.
1.Manual eradication of trees with chain saw and axe
2.Application of chemical biocide to the stumps to prevent any regrowth
3.Ripping of soil surface to a depth of 5 cm using a three tined hand implement
4.Application of dolomitic lime and raking it into soil after ripping of the soil
5.Application of organic material (cattle dung) after ripping and lime application
6.Oversowing with grass seed mixture after ripping of the soil and application of lime and organic material
7.Brush packing against contour and packing of rock contours against the slope All the branches and stones were collected from the restoration area. Rock contours were packed against (perpendicular) to the slope in the study area at varying intervals (approximately 10-15 m apart) in order to retard runoff water, trap soil, and improve conditions for seed germination (see inserted drawing below and attachment). Branches were packed (brush packing) along the slope in certain treatments within the study site in order to trap soil, retard runoff water en serve as a micro-climate for germinating and establishing grass seedlings
Total duration of restoration took 3 years, from removal of trees till revegetation trials were laid out and technology was established.
Maintenance / recurrent activities per year:
Following initial establishment maintenance was limited to 2 follow up applications of herbicide (after 3 and 5 months). Maintenance of contours was not done after restoration.
- 1-10 平方千米
Total area covered by the SLM Technology is 9 km2.
Big area near settlement, was previously invaded by alien invasive species (such as A. mearnsii). Aim was to eradicate this species by using chemical/manual methods and to revegetate area with grass species occurring naturally.
It originated from the overall need to restore degraded rangelands.
Major land use problems (compiler’s opinion): Occurrence of bare areas after control of alien invasive.
Major land use problems (land users’ perception): Minimal grazing for cattle, due to the occurrence of bare areas.
Grazingland comments: No area closure, thus livestock graze freely on statelands and thus causes overgrazing over a large area.
This is a constraint to management in grazing lands. No rotational grazing. No area closure, thus livestock graze freely on statelands and thus causes overgrazing over a large area.
Number of growing seasons per year: 1
Longest growing period in days: 210, Longest growing period from month to month: Oct - April
Specification of other agronomic measures: manuring, lime, 'brush packing' (trash lines)
Specification of other vegetative measures: oversowing grass seed mixture
Specification of other structural measures: stone lines
Type of vegetative measures: in blocks
Main causes of degradation: deforestation / removal of natural vegetation (incl. forest fires) (Alien invasives.), over-exploitation of vegetation for domestic use (Trampling.), overgrazing (Cattle and goat.)
Secondary causes of degradation: poverty / wealth (Lack of captial - To pay labours to apply technologies.), labour availability (Lack of labour - To remove alien species.)
Location: Elandsfontein. Gauteng
Technical knowledge required for field staff / advisors: high
Technical knowledge required for land users: moderate
Main technical functions: control of raindrop splash, control of dispersed runoff: retain / trap, increase in organic matter, sediment retention / trapping, sediment harvesting, increase in soil fertility, improvement of ground cover
Secondary technical functions: control of dispersed runoff: impede / retard, reduction of slope angle, increase of surface roughness, increase of infiltration, water harvesting / increase water supply, water spreading, reduction in wind speed, improvement of soil structure
Vegetative measure: contour
Vegetative material: O : other
Number of plants per (ha): 0
Vertical interval between rows / strips / blocks (m): 0.3
Spacing between rows / strips / blocks (m): 3
Vertical interval within rows / strips / blocks (m): 0
Width within rows / strips / blocks (m): 0.3
Vegetative measure: Vegetative material: O : other
Grass species: Mixture of perennial and annual grasses
Other species: rocks
Slope (which determines the spacing indicated above): 5.00%
|1.||Eradication of trees, Follow-up with herbicide||beginning of project|
|2.||Loosening of soil, Lime application||6 months|
|3.||Application of organic material||6 months|
|4.||Oversowing with grass seed mixture||6 months|
|5.||Brush packing||6 months|
Duration of establishment phase: 35 month(s)
|1.||2 Follow-ups with herbicide||after 3 & 5 months after application of technology /twice (at 3 and 5 months )|
Eradication, seed purchasing, materials.
Biocides, fertilisers (lime), seeds and labour have a great effect on costs.
- < 250毫米
- > 4,000毫米
600 - 800 mm/annum
- 0-100 m a.s.l.
- 101-500 m a.s.l.
- 501-1,000 m a.s.l.
- 1,001-1,500 m a.s.l.
- 1,501-2,000 m a.s.l.
- 2,001-2,500 m a.s.l.
- 2,501-3,000 m a.s.l.
- 3,001-4,000 m a.s.l.
- > 4,000 m a.s.l.
- 非常深（> 120厘米）
- > 收入的50%
Population density: 10-50 persons/km2
Annual population growth: 3% - 4%
80% of the land users are very rich (informal settlers and own 60% of the land (government).
20% of the land users are average wealthy and own 40% of the land (farmers).
Off-farm income specification: Informal settlers work in the city/mine, also mostly live of old age pension funds. Farmers (low percentage) have an income on-farm by means of selling cattle, crops and dairy products.
- < 0.5 公顷
- 0.5-1 公顷
- 1-2 公顷
- > 10,000公顷
- provincial government
- provincial government
Brush packing was removed by community members for firewood.
Not all labourers could be employed, more would have like to have the job (money).
Capacity building awareness
Farmers not positive about SWC project and effect.
10 land user families have adopted the Technology with external material support
1 land user families have adopted the Technology without any external material support
There is a little trend towards spontaneous adoption of the Technology
|Improvement of grazing resources.|
|Improved soil moisture availability by removing an alien species with a high water demand.|
|Reduced erosion by controlling runoff.|
|The question of controlling ‘open access’ grazing by the community is the key to long-term success of rehabilitation||It is incumbent on the local municipal council to negotiate with communities regarding grazing control and community-based natural resource management more generally.|
|Removal of brushwood for firewood by community members and other aspects of long-term maintenance||See above: perhaps also seeking funds to pay labourers and buy biocides|
|Too many cattle and goats.||Reduce numbers to match grazing resources available|
|Insufficient aftercare.||Secure additional funds to pay labourers and buy biocides.|
Soil classification: A taxonomic system for South Africa.. 1991.
ARC -Institute for Soil, Climate and Water, Pretoria. 012 - 3102500.
Harris J.A., Birch P., Palmer J.P. Land restoration and reclamation.. 1996.
Kent M, Coker P. Vegetation description and analysis.. 1997.
Tainton N. Veld management in South Africa.. 1999.
Acocks. Veld types of South Africa.. 1988.
HARRIS, J. A., BIRCH, P. AND PALMER, J. P. Land restoration and reclamation – Principles and Practices. Addison Wesley Longman, England. 230 p.. 1996.