Transcript AlterIrrigation2012 - Desert Restoration Hub

Alternative (more efficient)
Irrigation Systems
David A. Bainbridge
Author: 2007. A Guide to Desert and Dryland
Restoration. Island Press.
Retired, former Associate Professor, Alliant
International University, San Diego, California
Water shortage!
• The problem of water shortage continues to
grow - both locally and globally
• At the same time the need for restoration of
dry lands and increasing food production from
deserts and dry lands are both rising
• This led to my twenty five year adventure with
alternative irrigation systems
Desertification
Desertification:
now affects 1 billion people
Northern Mexico
The First Step
• This is not a “new” problem so I started
with an extensive literature search
• I also interviewed scientists and farmers
who visited the Dry Lands Research
Institute (at UC Riverside)
• Several interesting candidates
emerged, and have proved useful!
Buried Clay Pot Irrigation
• One of the most studied, and very
effective systems uses a buried clay pot
full of water to irrigate plants
• The capillary flow of water is regulated
by demand - so little water is wasted
• Highly recommended! For restoration,
gardens, landscaping, farming
Simple and Effective
• Clay pots worked
well even in the
lowest, hottest
desert in California
• Excellent for
seedlings or for
starting seeds or
cuttings
Getting Started
• Regular red clay
pots work well
• Seal the bottom hole
with a cork or
sealant
• Use a lid with a
small hole drilled in
it to capture
rainwater
Place the pot
• Set the pot in the
soil so the rim is
above ground
• You don’t want the
dirt and leaves to
wash in
• Firm the soil around
the pot -- and plant
A Long Tradition
• The agricultural text Fan Sheng-chih Shu,
describes the use of buried clay pot irrigation
in China more than 2,000 years ago
• Excerpts from this book provided my
inspiration--writing does speak across time
• I later found work and use of clay pots in Iran,
Pakistan, Mexico and other countries
Fewer Weeds
• Another great advantage of buried clay pots
(and other deep watering systems) is reduced
weed growth
• In one study weeds were cut 87%
• This means less work - and less wasted
water!
• The second biggest problem for small
farmers after water shortage is time shortage
Buried clay pots
• Buried clay pots have also proved to be
very effective when saline water must
be used - or when salt is a
problem in the soil
• The steady moisture reduces salt
buildup in the root zone and damage
Starting Cuttings
• Double clay pots are
ideal for starting
cuttings
• The inner pot is sealed
and filled with water
• The moisture is
maintained in the soil at
an ideal level
• BCP are good for
starting cuttings in the
field as well
Deep Pipe Irrigation
• This method of irrigation was suggested by a
traditional system from India - where water
was placed in the hollow stem of a dead plant
to water deeper in the soil
• Subsequent research found one study and
one report from India
• This has been our best system for restoration
work -- cheap, durable and very effective
Deep pipe installation
• The pipe may be
about 14-16” long,
2” diameter, set
vertically
• Small holes are
drilled on the plant
side below soil level
• A screen lid is glued
on to protect wildlife
Deep pipe drip
• Where a drip system
can be set up it can
also be used in a
deep pipe
• Smaller pipes can
be used with the
emitter inserted in
the pipe
No waste
• Little water evaporates because the
water is placed in the deep soil
• Little time is wasted because it is fast
and easy to fill the pipe
• It works very well on slopes
• It develops large root systems
Excellent Results
• Survival is excellent
with very little water
• Mesquite trees were
started with a total
of only 5 gallons of
water in the first
year - not five
gallons a week or
two gallons
an hour
Wick Irrigation
• Wick systems were also described in
reports from India
• Wicks were traditionally combined with
clay pots to water orchard trees
• After trying several types of wicks I think
this may be the next great thing!
Wick options
• Wicks can be used in a capillary form,
where water is wicked from a reservoir
to the plant through a raised section by
capillary forces (as little as 20 ml day)
• Or in a gravity feed form, with the
reservoir above the wick (a hose clamp
can be used to adjust the flow rate)
Wick options
• Wick with clay pot
• With a riser tube in
bottom hole
• Capillary wick from
buried bottle in
plastic tube
More wick options
• Half inch diameter
gravity wick with a
larger reservoir
• Installed with
treeshelter and wire
cage for jack rabbit
protection
• Seedlings topped
treeshelter at 3
weeks!
Wick Material
• The best material has been old, used 812 mm solid braid nylon rope (5/16”-1/2”)
• Fresh nylon rope can be used if it is
washed with detergent to remove oils but it is not as good as old rope
• Fabric ca also be used
• Cotton was used in India, but tended to
mold in my early tests
Porous Hose
• This system uses a vertically placed
leaky or porous hose section
• It performs a bit like a clay pot--only it is
cheaper and smaller
• These hoses are made of recycled
rubber and hold up well
• It has to be high flow rate hose to work
at low pressure head
Porous hose
• This can be fed by a
bottle
• Or attached to a drip
type line
• Both have worked
reasonably well
• A fast rate hose is
needed to work at
low pressure
Tree shelter
• Watering into a tree
shelter is also
effective
• This can be done by
hand or using a drip
type system
Perforated Pipe
• Sub-irrigation can
also be done with
slotted drain pipe
• The pipe is laid
deep in the soil and
filled with water
using a water truck
• Best for lines of
plants - good for
landscaping
Porous Capsules
• A modern adaptation of
buried clay pot irrigation
was developed in Brazil
• The clay is formed into
a capsule that can be
placed on a water line
• These worked well for
me -- but were more
costly to make
Types
• PC made by gluing
two red clay pots
together
• Clay pots made by a
staffer using a beer
bottle mold
Porous capsules
• These are easy to
plumb in a system
• Or they can be gravity
fed from a bottle or tank
• These are very efficient
indeed
• A range of smaller
porous irrigation
systems are sold for
container plants
Microcatchments
• A microcatchment is a specially contoured
area with slopes and berms designed to
increase rain runoff and concentrate it in
small dams or depressions
• Rain falling on the catchment area drains into
a planting basin where it infiltrates and is
effectively "stored" in the soil profile
• Used for millennia - very effective if it rains!
A Microcatchment
• Microcatchments
can be shaped to
look more natural,
but do entail
disturbing the soil
surface
• More appropriate in
agriculture - but has
worked well on
restoration projects
Problems with drip
• Drip irrigation has been very effective in
agriculture and is often the best choice, but
we can do better for the hundreds of millions
of farmers who cannot afford drip
• Water for drip must be filtered and
pressurized and maintenance is critical
• It is also not as efficient as these alternatives
- some may be 2-4 times more water efficient
than surface drip
Drip problems
• Drip is not well suited
for remote sites - due to
animal damage
• Even when open water
is nearby animals will
chew on drip tubing
• Insect, root and salt
clogging and other
problems also occur
regularly
The best system?
• It depends
• All have been very good
• Deep pipes have been most commonly
used
• Perforated pipe is now used in some
situations (linear plantings Mojave)
• My current research is focusing on
wicks - low cost, durable
Container type
• The container type and
planting system make a
difference in irrigation
choice
• Tall pot, half high, deep
pot, plant band or
supercell?
• Watering interval
• Goals for survival and
growth
How efficient?
• My goal has been to irrigate plants with
minimal water use -- perhaps a quart a
month for species like mesquite
• This has been possible if they are also
planted with a tree shelter to reduce
temperatures and exposure to the wind
• They don’t grow much - but they survive
until it rains
Restoration in remote places
• My goal has been to
reduce water use
during establishment
to a low enough level
to be done by hand
carrying water
• Or using a mule,
many miles from the
water source
It is possible
Planted 1995, photo 2008
More information
• A wide range of papers and web sites
• Try ecocomposite.org
• Sakia.org
• And for more information on desert
Restoration
www.desertrestore.org
www.desertrestore.org
June 2007
You Can Help
• Try these systems -- figure out how to make
them better, cheaper and more efficient
• Find out what works and what doesn’t and let
me know [email protected]
• Send money to support research
• Buy my book on desert and dryland
restoration and send it to a library or
university in Africa, Mexico, Asia
Thanks
• To friends, students (AIU, SDSU, UCR, WCIU), staff, funders,
vendors and family who have helped along the way
• To the traditional farmers who figured most of this out -- and
shared information and ideas freely
• Special thanks to Steve Mitchell, Wes Jarrell, Ross Virginia,
Mike Allen and John Rieger who made this possible
• And to the many scientists and extension specialists who have
provided insight and descriptions of traditional irrigation systems