International Water Management Institute for the financial support that ensured the success of this project.
INTRODUCTION
The disempowering development and management methods used in the past have resulted in a strong dependence on government by small farmers. To evaluate the technologies, a literature review was conducted to determine the factors influencing the use of irrigation technologies by smallholder farmers.
A REVIEW OF SMALL-SCALE FARMING IN SOUTH AFRICA
South Africa is a water-poor country, with only seven percent of the total area receiving more than 800 mm annually (Schulze, 1997). Grosby and de Lange (1998) suggest that gardens should be developed as a community initiative.
The role of government and non government organisations
Due to the top-down management structure, farmers had little decision-making power and the scheme was seen as owned by the government rather than owned by the farmers themselves (Crosby and de Lange, 1998). It is assumed that farmers will respond favorably to economic incentives as perceived by planners (Underhill, 1984).
The role of designers and manufacturers
Of the different irrigation systems, the sprinkler method is the closest to natural rainfall. A farming systems approach was therefore used in the evaluation of the irrigation technologies selected for this project.
Materials used and design criteria
The first set of suction pump valves is located at the bottom of the cylinders. It is similar to the valves on the bottom of cylinders and contains a mesh that is used as a strainer.
METHODOLOGIES
Maximum flow rate
This was not necessarily as fast as they could tread, as this caused the water to spill over the top of the cylinders of the suction pumps. A maximum flow rate for each operator for each pump was then calculated by dividing the volume obtained by 40 seconds.
M echanical efficiency
If the operator moves away from this position and increases the distance from the pivot point of the treadles, a greater force can be applied to the pistons. This ratio of the distance of the operator and the piston from the pivot point is known as the mechanical advantage (Kay and Brabben, 2000). The height of the table, 0.8 meters, was included in the suction heads for the suction pumps.
The efficiency of a step pump can be defined as the ratio between the output power and the input power. Air was also drawn through the O-ring at the top of the cylinder. The height of the frame can be adjusted to the height of the operator and the different heights of the pumps.
The Approtec pump always started easily after a little water was poured into the top of the cylinders.
Kwaggafontein
A non-return foot valve was placed at the end of the inlet pipe to prevent water from flowing out when pumping stopped. A stopwatch was used to record the time it took to fill a 25 liter bucket and then the flow rate was calculated. Plot layout used for foot pump testing and hose pipe application.
One farmer pumped while another held the other end of the hose and watered the beans. The Approtec pump was used to pump directly into a bucket system and into two different sprinkler systems, an impact sprinkler and a cone sprinkler. The bucket and stopwatch were again used to measure the flow rate of the water.
To determine the distribution uniformity of the sprinklers, collection trays were distributed in the garden.
Drip Kit Qualitative Assessments
Ley and Thomas (1994) state that the ceramic tip of the tensiometer should be placed in full contact with the soil. In selected growing season intelVals, approximately once a month data were uploaded to the HOBO Shuttle (Onset, 2000). The voltage of the batteries was checked and the tensiometers were filled with aerated water.
The date of transfer and top-up was noted, as this affects tensiometer readings by several hours. In the first season, two front welding detectors were installed on one of the spinach plots. The dimensions of the funnel are such that the soil at the bottom becomes completely saturated.
A lightweight foam rod floats on the water inside the tube and rises out of the tube.
South Africa has access to more resources than most other African countries;
This chapter presents the results obtained from the evaluations of the various technologies and techniques. Initial adjustments had to be made to some of the Zambian pumps as they were not of very high quality. The steps had been attached to the wrong end of the pump, reducing the mechanical advantage.
A leather cup, purchased locally, was used in one of the cylinders as it was a tighter fit than the rubber cups. The brass foot valves obtained from the pumps did not close properly, causing water to leak from the inlet pipe. The pump tilts when the operator is on the other side of the pedals.
The suction height of the three suction pumps did not appear to affect the average flow values.
PLATFORM
SWAZI PUMP
APPROTEC
SWISS PUMP
KB PUMP
IDE PUMP
Operators' opinions
All three operators found the Approtec pump to be very stressful on the front of the thighs at low heads. The hole at the top of the cylinder for the piston rod can wear out with frequent use. The next section presents the results obtained during the field testing phase of the step pumps.
In the case of the Approtec pump, this was because the pump did not raise the water to the minimum required head of one meter. With the treadle pump and hose method it was therefore faster to irrigate a row by more than a third of the time. The graphs showing the profiles of the two different sprinkler systems used can be seen in Appendix E.
However, the pump was quite stiff to pump due to the resistance of the sprinkler.
Drip Kit Qualitative Results
An event on September 19 affects the 298 mm strain gauge immediately and has a delayed effect on the 662 mm strain gauge. The 1000 mm tensiometer shows a slight drying of the soil profile around May 25. All three tensiometers respond to the irrigation event on May 14, where the response was slightly delayed for the 1000 mm tensiometer.
A sudden drop occurs in the 1000 mm tensiometer due to replenishment that occurred on 25 May. The 298 mm tensiometer loses contact first on 19 September, followed by the 662 mm and then the 1000 mm tensiometers which are delayed. Irrigation events on 2, 3 and 4 October appear to affect the 298 mm tensiometer and an event on 12 October affects the 298 mm and 1000 mm tensiometers.
The 298 mm tensiometer appears to work only until June 8 and shows a gradual drying out.
WETPIPE
It appears to function properly after topping up on May 25th, then loses contact again around June 1st after reaching a voltage of nearly 8000mm. The other two tensiometers show a drier soil profile than the previous summer season and show a steady drying over the season. The 1000 mm tensiometer appears to be steady by about 5 June and continues to oscillate around about 6000 mm soil matric pressure.
You can see the data from the reference nest for both seasons in Figures 44 and 45.
Prototype two
The operator said that the pump was easy to pump and did not require much effort as it did not offer much resistance. This was probably due to the light ball valves opening and closing rapidly with each stroke. However, this will limit the pump to a certain position in a garden, unless more than one frame is built.
The big advantage of this pump is that it is cheaper than all the others, including the prototype of one pump.
DISCUSSION AND CONCLUSIONS
- Drip Irrigation Kit Qualitative Assessments
- Conclusions and Recommendations
The cylinder size should also depend on the size of the piston cups that can be easily obtained. The valves are the other measure of the amount of water that can be pumped. It is important to match the desired water volume of the pump to the size of the holes in which the valves are made.
The size of the inlet and outlet pipes also affects the amount of water that can be pumped. The meetings and site visits held in the early part of the project produced results that showed possible areas of use for foot pumps in South Africa. The qualitative evaluations of the drip irrigation kits were not as successful as the foot pumps.
It is critical that the technology is seen in the context of the smallholder farming system.
Foot pumps - an irrigation technology tailored to the needs of small farmers [Internet] HR Wallingford, Wallingford,. A low-cost drip irrigation system for smallholder farmers in developing countries [Internet] International Development Enterprises. WRC Report 719/1/98 by the Faculty of Agriculture and Agricultural and Rural Development Research Institute, University of Fort Hare to the Water Research Commission, Pretoria, South Africa.
Irrigation requirements of selected crops under small-scale production: linking on-farm and station research. WRC report 689/1/00 by Institute for Soil, Climate and Water, Agricultural Research Council to the Water Research Commission, Pretoria, South Africa.
APPENDICES
Are there ever arguments amongst the farmers, why? No
CURRENT INFRASTRUCTURE
What is th eir level of techni cal und erstanding ?
What are the reasons for past crop failures? None
How efficient is the current system? Unknown
What are the temperatures at the site, is there much evaporation? High temperatures
CURRENT INFRASTRUCTURE
The Department of Agriculture is installing irrigation systems in many community gardens in KwaZulu-Natal as part of the Chase the Hunger project. During a recent visit to one of the gardens, they found that the farmers are again watering by hand. The FSCS recognizes that the system is not very uniform in terms of the water used for each plant, but it is cheap and farmers grow for their own consumption rather than for commercial purposes.
The valves at the bottom of the shaft can be very easily reached and replaced. The rest of the pump is supported by a holder, which can be a steel frame or a concrete base. The pump was still in the planning stages at the time of the visit, but will sell for around R800 when it is built.
Tables 26 to 29 show the materials required for the various sections of the two pumps.
AMOUNT DIMENSIONS NAME COST
SWAZI
SWISS
Av. effic
Operator A
Operator B
Operator C
IMPACT
GARDENA
