DEVELOPMENT AND PERFORMANCE EVALUATION
OF KAU MICRO SPRINKLERS
K.P.Visalakshil, Reena Mathew, P.Suseela and T.K. Bridjilt
ABSTRACT
The research works carried out at the Agronomic Research Station,
Chalakudy, Kerala Agricultural University for the development of an
affordable, dependable, simple and farmer friendly technology, resulted in
a low cost micro sprinkler head. The rotating sprinkler head is made of a
small piece of 12-mm/8mm-diameter good quality LDPE pipe, plugged at both
ends. It is provided with 1 mm diameter nozzles 5mm away from both ends on
opposite sides. A 6 mm diameter micro tube is attached to the sprinkler
head unit at the center through the pin connector. The other end of the
micro tube can then be attached to the lateral, thorough another pin
connector. The micro tube with the sprinkler head unit is tied to a riser
pipe, fixed near the plant to be irrigated. The moment of couple
constituted by the stream coming out of the nozzles causes the emitter to
rotate while in operation. The performance of these sprinkler heads were
evaluated by observing the effective wetting area, discharge rates, water
distribution pattern, variation of effective wetting area with different
pressures and heights of riser pipe etc. The micro sprinklers discharge 35
40 1/h, wetting an are of 2 2.5m. Diameter, under 1 2kg/cm pressure.
For close growing crops, the investment cost is Rs.10,000 less then that
required for drip irrigation system. Lesser clogging susceptibility, more
distribution uniformity, reduced investment costs etc. are the special
advantages of the developed micro sprinkler system.
INTRODUCTION
Water being a scarce resource, its efficient and economic use is of utmost
importance in agriculture. Micro irrigation, system viz. Drip and
sprinkler were developed and tested for higher water use efficiency in
several crops. But the sophisticated design of its components, frequent
clogging of emitters and high initial cost became the major constraints in
the large-scale adoption of this technology by many farmers.
The research works carried out at the Agronomic Research Station,
Chalakudy, Kerala Agricultural University for the development of an
affordable, dependable, simple and farmer friendly technology, resulted in
a low cost micro sprinkler head (Sreekumar et.al 1998). Water is delivered
through a net work of main pipes, sub mains and laterals and falls as a
circular spray through these micro sprinkler heads. It is very simple in
design and clog free system of irrigation, ensuring complete wetting of
the basin area of the crop. It can be considered as a unit in between drip
and mini-sprinkler systems.
KAU MICRO SPRINKLER IRRIGATION SYSTEM
The sprinkler head is made of a 6 cm long piece of 12 mm/8mm diameter good
quality LDPE pipe, plugged at both ends by end caps. These were provided
with 1mm diameter nozzles 5mm away form both ends on opposite sides. A 6
mm diameter, 1.0m long micro tube is attached to the sprinkler head unit
at the center through the pin connector. The other end of micro tube can
then be attached to the lateral, through another pin connector. The micro
tube with the sprinkler head unit is tied to a riser pipe, fixed near the
plant to be irrigated. The moment of couple constituted by the stream
coming out of the nozzles causes the emitter to rotate while in operation.
The performance of these sprinkler heads were evaluated by observing the
effective wetting area, discharge rates, water distribution pattern,
variation of effective wetting area with different pressures and heights
of riser pipe etc. The micro sprinklers discharge 35 40 1ph, under 1 2
kg/cm pressure wetting a circular area of 2 2.5m. Diameter (Visalakshi et
al 2005).
PERFORMANCE EVALUATION
For evaluating the performance of various sprinkler heads and also to
arrive at a design criteria, studies were carried out under AICRP (WM).
Micro sprinkler heads with different combinations of pipe sections and
configurations were tested. This included diameter of sprinkler head (8mm,
12 mm and 16mm), length (5cm, 8cm and 12cm), number of nozzles (1,2 and 3)
and diameter of nozzles (1mm, 2mm and 3mm). However, the units with
nozzles of larger diameter and more numbers performed satisfactorily only
under high pressures. Since this sprinkler head is meant for small and
marginal farmers, units that require an operating pressure of 0.3 to 1.0
kg/cm2. Which is easily available even from a domestic overhead water tank
was recommended for farmers use. The performance of these sprinkler heads
were evaluated by observing the effective wetting area, discharge rates,
water distribution pattern, variation of effective wetting area with
different pressures and heights of riser pipe etc.
The sprinkler head performed best during the study were MS-8, 5,N1, 1
(Micro sprinkler head of 8mm dia, 5cm long, with one nozzle of 1mm dia)
and MS-12, 8, N1, 1 ((Micro sprinkler head of 12mm dia., 8cm long, with
one nozzle of 1mm dia). Uniformity of the system was evaluated using catch
cans and distribution efficiency of 86 to 90 per cent could be achieved in
both the units. The diameter of the nozzles was found to deform after 3-4
seasons and hence the sprinkler heads are to be replaced by new ones,
which may cost only Rs.0.40.
Sprinkler head MS-8, 5,N1, 1; that gave fine spray and maximum effective
wetting area, were recommended for leafy vegetables, ornamental plants,
lawn etc. It is also recommended for greenhouses for controlling the
micro-climate. Sprinkler heads MS-12, 8,N1, 1 were recommended for
vegetable crops, banana, medicinal plants, coconut etc. The
characteristics of these two sprinkler heads are shown in table .1. The
area of coverage can be increased or decreased by adjusting the height of
riser pipe, according to crop growth. The duration of irrigation
application is fixed as per the water requirement of crops.
Table 1. Characteristics of the best performed units
Diameter 8mm 12mm Length 5cm 8cm Nozzle size 1mm 1mm Pressure required for
working 0.3 1.0 kg/cm2 0.3 1.0 kg/cm2 Discharge rate 30 35 liters
per hour 40 45 liters per hour Wetting diameter 210 250cm 200 230cm
Height of riser pipe 30 90cm 30 90cm Crops suitable Leafy vegetables,
ornamental plants, lawn etc. Vegetable crops, banana, medicinal plants,
coconut etc.
The approximate cost of installation excluding pump sets for an area of
one acre is Rs.15, 000/- for coconut (7.5m X 7.5m) and Rs.24, 000/- for
vegetables (2m X 2m). By careful maintenance, the above network of pipes
can be used for 8 to 10 years.
ADVANTAGES OF THE SYSTEM
1. Does not have any sophisticated components.
2. Lesser operating pressure.
3. Clogging susceptibility is almost nil.
4. More distribution uniformity in crop root zone.
5. Complete wetting of the basin area, providing a cool environment for
plant.
6. Allows application of fertilizers, and herbicides and cooling of green
houses, poultry houses, cowsheds etc.
7. Initial investment, running cost and maintenance. Cost is reduced
considerably.
REFERENCES
1. Sreekumaran, V., Santhakumari, G., Jayakrishnakumar, V.
and Reghu.P.K. 1998. Bubbler irrigation system (BIS)
An innovative micro irrigation system. Preceedings of the 10th Kerala
Science Congress. KSCSTE.,
Thiruvananthapuram, pp: 494-496.
2. Visalakshi K.P., P. Suseela, T.K..Bridgit., Reena Mathew,
V.S.Devadas and mini A braham. 2005. KAU Micro
Sprinkler. (Booklet) Kerala Agricultural University,
Thrissur, Kerala.
Source: Journal of Indian Water Resources Society, Vol 27, No 3-4, July-
October 2007, pp 17-19.
