GEMA 2 (2017-2020)
Done By:
Hazael Boodhram, Yash Boykunt,
Nikesh Bhundoa, Akshay Deerpaul,
Elias Dosemohamed, Darryl
Chengareddy, Vyas Bonamally,
Michael Chan
Acknowledgment
We would like to thank each of our team members for making this report possible and a special
thanks to Mr. Pierre Nadal from Aqualia Mauritius for his support during those weeks.
Executive Summary
This report provides a basic introduction to and overview of linear move systems, including key
components of the system and basic interconnections among components.
With increasing pressures to improve water use efficiency, plant productivity and farm
profitability, questions continue to be raised concerning the future direction of irrigated
agriculture in the world. Linear move systems technology is a primary method for irrigating
farmland and plays an important role.
This image illustrates that the linear move connects to pumping systems, telemetry systems,
and control systems. The center pivot, while at the heart of the irrigation system, relies upon an
entire set of intersecting systems, controls, and data connections.
Introduction
A linear irrigator moves in a straight line and irrigates rectangular land areas, making them ideal
for cropping. These machines can irrigate long runs of more than 2000m and offer short
rotation times to minimize water loss and achieve optimum crop growth. These systems are
self-propelled irrigation systems. They apply water to a crop or pasture generally above the
crop canopy.
Linear Moves (or Lateral Moves) have both ends of the machine move at a constant speed up
and down a field. The pump and power source are located at one end or in the middle or on a
mobile cart. Water is supplied to the cart via lay flat hose, hard hose or open channel. The
power supply can be diesel gen-sets for electric machines, diesel hydraulic power packs for
hydraulic machines or mains (electric) via a dragged cable for electric and hydraulic machines.
The main components of these systems are the self-supporting frame spans. Each span is
supported by wheeled towers, which incorporate gearboxes, drive wheels and electric or
hydraulic drive motors. The frame supports (or is incorporated with) water delivery pipes.
Emitters (either sprinklers or low energy precision application (LEPA) fittings) are attached
either directly to the main pipe or suspended closer to the crop on rigid or flexible droppers.
The pump delivers a flow rate within a fixed range, and the machine speed determines the
depth of water that is applied. Each span acts as an independent unit, so that the machine can
be used over undulating ground. This is achieved using flexible couplings joining each span.
System alignment is achieved through micro switches, alignment levers and control equipment.
Types of Moving Irrigation Systems
Linear/lateral move
Centre Pivot
Linear/lateral move
Sup
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Pivo
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Use
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Pivot system layout
Center pivot irrigation is a form of overhead (sprinkler) irrigation consisting of several segments
of pipe (usually galvanized steel or aluminum) joined together and supported by trusses,
mounted on wheeled towers with sprinklers positioned along its length. The major components
include:
Pivot
Pivot Tower
Control Panel
Spans of pipe between towers
Trusses to support the spans
Tower drive Wheel
Pros & Cons for Pivot Systems
Center pivot systems offer many advantages over other irrigation application methods:
Potential for automated operation, reducing labor costs
Simplified and predictable water delivery
Ability to apply to more shallow depths
Uniform distribution of water
Increased ability to plan and schedule irrigation applications
Easier to apply Agri-chemicals (chemigation)
Little annual setup required
Reliability
Disadvantages of center pivot systems include:
Relatively high initial cost
Relatively high pipe-friction losses
Circular pattern leaves dry corners and potentially lower yield
Topographic changes cause potential operating pressure variations
Can have operational challenges requiring human interventions
Potential risk for injury if the operator is not familiar with operation
Pros & Cons of Linear Move
Advantages
Reported application efficiencies for new well-designed machines
Reduced variability are generally in the 80–95% range, compared to 50–90% for surface
irrigation systems.
Able to apply a prescribed volume to match crop water
requirements. Reduced opportunity for surface runoff or deep
Precise applications percolation if the system is designed to match soil infiltration
characteristics. Ability to irrigate in winter with lower risk of
waterlogging.
Can work on rolling topography, variable soils and shallow soils that
are not conducive to landfarming. Will likely require some
Less landfarming landfarming for surface drainage of rainfall induced runoff. Essential
to have adequate drainage and reuse capacity
Can concentrate on irrigation scheduling and maintenance rather
than ensuring application uniformity. Labor requirement is generally
Lower labor lower but depends on the system, the degree of automation of the
requirements machine and the supply system upstream of the machine, the design
of the system and ongoing management and maintenance
requirements.
Improved agronomic By ''replacing'' water rather than refilling soil profiles, there is a
conditions and reduced lower risk of deep drainage, and soil temperatures and aeration
potential for deep status may be more favorable for plant growth/germination. Can
drainage leach salts efficiently using less water than surface systems.
Fertigation allows the targeted application of small quantities of
Opportunities for nutrients, with a reasonable uniformity of application and less risk of
fertigation nutrient losses. The irrigation system may also be used to apply
herbicides and pesticides
Able to either pre-irrigate and sow directly into soil moisture, or dry
sow crops and „water up‟. Sowing crops on-time is one of the critical
Ability to sow on-time components in maximizing yield potential. Timely pre-watering also
allows for knockdown herbicide application.
Disadvantages
Sprinkler systems have a relatively high capital cost compared to surface
irrigation systems, unless substantial landfarming is required for optimum
Cost performance of the surface system. Longer-term performance of the sprinkler
system may be compromised by designs that reduce initial cost. Running costs
can also be significant – and need to be evaluated during the design process
Energy Pressurized irrigation systems require some form of energy source to operate,
requirements increasing demands on power distribution networks
Layout and
soil It can be difficult to match certain systems (i.e. center pivots) to existing
consideration rectangular field layouts. Some vegetation may need to be removed for optimal
s performance of the sprinkler system. Soil variation under the one machine can
lead to compromise – one soil, one machine
Water quality Water may need to be filtered before use to prevent system blockages, with
consideration sediment laden waters allowed to settle before use. Some issues with foliage
s damage from overhead application of salty water in arid environments. Poor
water quality can affect longevity of irrigation infrastructure.
Skills Operation and maintenance of sprinkler irrigation systems will require different
requirement skills to surface irrigation systems.
Assumptions
Field Size: 10 000 m X 500 m
Borehole depth: 50 m below surface
Crops to be irrigated: Sugar cane
Total Number of spans: 10
Power Source: Solar
How should it be working?
The system should be working on an alternating span operated. To explain it more briefly if the
system has four spans and it moves from line A-A’ to B-B’, spans 1 & 3 only should be irrigating
the field till it reaches line B-B’ and when moving from line B-B’ to A-A’ spans 2 & 4 only should
be in operation
.
A B
Span 1
Span 2
Span 3
A’ B’
Span 4
Why alternatively?
Since the system will be solar powered, if all spans irrigate at the same time for the area
assumed (10 Km X 0.5 Km), we will have to invest even more money in a solar farm for it to
operate.
