Soil preparation for dryland and restoration success. Site evaluation and treatment to improve damaged soils. Capture water, reduce erosion, speed growth and improve survival.

1. Improving the Soil for
Dryland Restoration
Success
David A. Bainbridge
Restoration Ecologist

2. Understanding disturbance
• Start with a site
history
• Then field checks
– infiltration
– soil strength
– fertility
– micro-topography
– water flow
– ecology
Infiltrometer studies

3. Decompaction
• Most restoration sites will benefit from
ripping, subsoiling, forking or
decompaction
• Rototilling is less desirable but can help
• A spader is a better choice because it
does not invert the soil or leave a tiller
pan - but not widely available

4. Soil treatment
• Hand treatment is
possible but costly
and often not very
effective
• A tractor with ripping
teeth will help with
road restoration
• Spaders can loosen
soil and fold in mulch

5. Surface configuration
• Once the soil is loosened up it can be shaped
to improve water retention and create planting
spots
• Pitting, basins, imprinting, ridges, and other
contouring can be done by hand or machine
• Try to understand the topography at the macro
and micro-scale
• Think watersheds

6. Check dams
• Check dams may be
needed to protect flow
channels
• These can be rock,
gabion, brush
• Permeable dams are
generally more resistant
• Design for overflow and
undercut, side cut
protection

7. Soil Pitting
• Pitting is often the best
alternative
• Increases water
retention - up to 1000
cubic feet per acre
• Creates spots that
capture dust, micro-
organisms, seeds
• Pitting, mulch, seeding
and container plants at
Hungry Valley shown

8. Basins
• Larger pits can also be made with a machine or by
hand
• I often used hand labor - but would recommend
equipment now (a small excavator would be very
effective)

9. A Camel Pitter
• I would also buy a
Camel pitter
• This can be hauled
behind a truck or
larger SUV
• Low cost easy to
transport

10. Imprinting
• Bob Dixon’s imprinters have worked
very well in some cases
• They make micro-watersheds with a
large drum with teeth designed for
specific rainfall/soil conditions
• Larger models can even imprint asphalt
(be careful)

11. Imprints
• I have found they do
not work as well in
the California winter
rainfall deserts
• But in bimodal
rainfall areas they
have been effective
• Good for rangeland
rehab

12. Ridges and catchments
• Ridges and contour catchments can help
• A very low cost option for abandoned ag lands
Jackson

13. Big pits and trenches
• For severely
damaged
areas big pits
and trenches
may be used
to hold water
on the land
Paani Foundation work in India

14. Erosion control
• Save the soil by thinking about water
flows and erosion
• Check dams, contour lines, rock lines,
brush, mulch, straw
• Cheaper to prevent than restore
damage
• Beware of water run-on to your site from
the watershed above

15. Straw flake dams
• Flakes of weed seed
free straw placed in
trenches are very
effective and low
cost
• Unlike straw wattles
in netting there is no
risk of entrapment of
reptiles

16. Punched straw
• Straw can also be
punched in by hand
• Rice straw will last for
several years
• Rice straw is also less
likely to have desert
adapted weeds
• Termites will eventually
get to itPunched straw after 5 years

17. Bark and brush
• Recalcitrant
mulch can also be
very helpful
• Bark, chipped
wood, almond
hulls and other
heavy materials
will resist wind
• They provide food
for organisms
Bark mulch after five years

18. Brush spreading
• Organic matter and
brush from
construction projects
can be respread
• Reducing erosion
and saving many
seeds, organisms
• Discourages OHVs

19. Matting, fabric, etc.
• In some cases coir
fabric, jute netting, or
straw/mesh mats can be
used
• These are expensive
and usually only used
near buildings, roads or
steep slopes
• Pin or weight carefully to
resist wind
In an experimental plot the best cover and
greatest number of plants per square
meter (7 times control) were in punched
straw, followed by EncS2 straw/coir mat,
and jute netting. Coir mat was better than
control with almost 3 times as many plants.

20. Straw wattles
• One of the most
commonly prescribed
erosion control methods
• Rarely installed correctly
• Must be set in a trench
and pinned to work well
and resist wind
• Entrapment of reptiles in
the netting reported in
the desert
Straw wattle set in trenches and pinned
with rebar staples

21. Rock lines
• Simple rows of
rocks on the
counter can slow
water flow and
reduce erosion

22. Fertility
• Soil fertility is rarely a problem
• Most desert plants are adapted to low nutrient levels
• Nitrogen deposition from air pollution in fact, may be
helping drive the invasion of alien species
• However - check levels, added phosphorus may help
root development in borrow pits
• Be aware of alkali, salts, boron, selenium
• Check organic matter - low is expected but none can
be a problem

23. Soil salvage
• Topsoil can be scraped
off and saved
• This is costly but can
be very effective
• Seeds, organic matter
and organisms can all
be respread
• Best if done quickly but
can be stockpiledCMM soil salvage operation

24. Soil Ecology
• More costly to check but a good
indicator of soil health
• Check mycorrhizal fungi - spores or
bioassay
• Check rhizobial bacteria - N fixers by
bioassay or root checks
• Compare ant colony counts on disturbed
v/s less disturbed areas

25. Cryptobiotic crusts
• Living crusts are often
important
• Even in the desert we
see them in some
locations
• Even when you don’t see
them they may be
present
• Protect them
• You can try inoculation
but I have not had much
luck

26. Integrated treatment
• Soil treatment is an often neglected
aspect of desert restoration
• Understand what was and what is
• The plants that used to grow may be
unsuitable for current soil conditions
• Soil rehabilitation and time may be
needed to restore soils to health

27. How as the site changed?
• Worst case scenario
– Borrow pit
– 20 feet of soil removed
– All plants and organisms
removed
• Not quite as bad
– OHV damage in state
park
– Soil compaction and plant
destruction
– Changes in soil texture
CalTrans borrow pit
ABDSP Hill climbs

28. Success
• Getting it right will take thought, careful
work, monitoring and followup
• Managing soil and water are intimately
related
• Restoring plant cover helps - the shrubs
help capture dust and nutrients
• These islands of fertility provide habitat
for many other species

29. Mesquite Nebka Mound
• How much dust and sand can a plant capture?
Quite a bit!
• These plant mounds or nebkas are very
important ecologically

30. Soil treatment - before

31. Soil treatment - after
• Ripped, pitted, mulched and seeded
• The image on left is hill top exposed, grasses
on the right are on a north facing slope nearby
(same seed mix) after 3 years

32. Soil restoration is possible
• Think it through
• What problems are evident?
• Test
• Then
– What can you do?
– What equipment is available? Allowed?
– What can you afford?
– When? How? Who?
• Monitor and followup

33. Scale is important
• One of my
mistakes was not
using more
equipment
• This was driven
by budget
restraints
• Remote sites
• But sometimes
you just need a
tractor!

34. Further reading
• A Guide for Desert and Dryland
Restoration. Island Press.
• Gardening with Less Water. Storey
Press.
• The Mojave Desert: ecosystem
processes and sustainability.
University of Nevada Press.
• Restoration of arid and semi-arid
lands. Chapter 10 In J. van Andel
and Restoration Ecology: The New
Frontier. Blackwell.
• The California Desert. 2 volumes.
June Latting Books.
• http://works.bepress.com/
david_a_bainbridge