To Make a Desert Bloom: Exploring Israel

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To Make a Desert Bloom Exploring Israels
Experience in Combating DesertificationAlon
Tal, Ben Gurion University
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Israel Land of Steep Gradients

• Tiny in size (22,145 km2)
• Climate short, cool rainy winter,
• long, hot dry summers.
• North/south rain gradient (700-30 mm)
• Evapotranspiration increase (1200-2800)
• A west-east ecoclimatic gradient
• Elevation gradient of 1200 m above sea level (to
  400 m below sea level)

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Mark Twain Innocents Abroad, 1867

• On general Galilee landscape "as bald and
  unthrilling a panorama as any land can afford
  perhaps was spread out before us."
• On Local agriculture "Here were evidences of
  cultivation - a rare sight in this country- an
  acre or two of rich soil studded with last
  season's dead corn-stalks of the thickness of
  your thumb and very wide apart. But in such a
  land it was a thrilling spectacle.
• On the effects of overgrazing "Close to it was
  a stream and on its banks a great head of curious
  looking Syrian goats and sheep were gratefully
  eating gravel. I do not state this as a petrified
  fact - I only suppose they were eating gravel
  because there did not appear to be anything else
  for them to eat

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Twain, ctd.

• On absence of forests "There is no timber of
  any consequence in Palestine - none at all to
  waste upon fires - and neither are there any
  mines of coal.

Description of the Judean hills "There was
hardly a tree or a shrub anywhere. Even the
olive and the cactus, those fast friends of a
worthless soil had almost deserted the country.
No landscape exists that is more tiresome to the
eye than that which bounds the approaches to
Jerusalem."
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Observations of a Soil Scientist

• 1938 "Here before our eyes the remarkable red
  earth soil of Palestine was being ripped from the
  slopes and swept into the blue of the
  Mediterranean to a dirty brown as far as the eye
  could see. We could well understand how many
  centuries this type of erosion had wasted the
  neglected lands. It is estimated that over three
  feet of soil has been swept from the uplands of
  Palestine after the breakdown of terrace
  agriculture
• Walter Clay Lowedermilk, Palestine - Land of
  Promise, New York Harper and Brothers, 1944

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Historic Climatic Factors

• Hypothesized main winds bringing loess to Negev
  desert prior to the Holocene came from the
  Sahara, (Evenari et al.1982).
• No net erosion during this period.
• Since Holocene wind directions have changed and
  loess arrives in the Negev desert from Saudi
  Arabia, a far shorter distance.
• Less loess reaches the desert to replace that
  lost in the floods. This results in net erosion,
  which is a natural process (Avni 1998).

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Desertification trends Conventional View

• Prior to State of Israel
• Pollen analysis shows Mediterranean Forests.
• For millennia intensive human utilization of dry
  subhumid/semiarid parts of current Israel.
• Results are described by travelers
• - Woodlands converted to scrublands.
• - Overgrazing in ranges.

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• Because of low rainfall and hence low primary
  productivity, regrowth of vegetation could not
  keep pace with its destruction, especially in the
  presence of overgrazing by abundant goats. With
  the tree and grass cover removed, erosion
  proceeded and valleys silted up, while irrigation
  agriculture in the low-rainfall environment led
  to salt accumulation.... Thus, Fertile Crescent
  and
• Eastern Mediterranean societies had the
• misfortune to arise in
• an ecologically fragile
• environment. They
• committed ecological
• suicide by destroying
• their own resource base.
• Jared Diamond

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Soil Erosion Map, 1954
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Pre 1948 - Conclusion

• The country was desertified, but the impact
  diminished with aridity. The expression of
  desertification might have been soil salinization
  in dry subhumid areas, and definite loss of
  natural vegetation and soil erosion in dry
  subhumid and some semiarid areas ecological and
  hydrological processes would have been disrupted,
  the provision of ecosystem services have been
  impaired, resulting in an overall gradual decline
  in productivity.
• - Professor Uriel Safriel

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1920 Survey only 600 km2 of indigenous woodland
and scrubland in dry subhumid regions between
present Israel and West Bank
Shaar Hagai
1987
1917
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The Green Zionist Vision

• We have come to our land to build and to be
  built up.
• Barren slopes afforested
• irrigated farming -- Esp. in plains/valleys.
• Southern exigency

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• "Along with the records of decay in the Holy
  Land we found a thorough going effort to restore
  the ancient fertility of the long-neglected soil.
  This effort is the most remarkable we have seen
  while studying land use in twenty-four countries.
  It is being made by Jewish settlers who fled to
  Palestine from the hatreds and persecutions of
  Europe. We were astonished to find about three
  hundred colonies defying great hardships and
  applying the principles of co-operation and
  soil conservation to the old Land of
  Israel..... here in one corner of the vast Near
  East, thorough
• going work is in progress to rebuild the
  fertility of land instead of condemning it by
  neglect to further destruction and decay. (W.
  C. Lowdermilk, 1944)

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Israeli Policies to Combat Desertification

1. Irrigated Agriculture
2. Water Management
3. Control of Grazing
4. Afforestation

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Jewish Settlement in semi-arid zone
I
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Typical Impact of Cropland Conversion

• Transformation of rangeland
• a driver of desertification
• (removal of vegetation cover
• and breakage of biogenic crust
• through plowing.)
• - When land not tilled during
• non-rainy season wind erosion
• rains generate physical crust
• - intensifies run-off/erosion.

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Rangeland Transformation in Israel

• In Israel - most rangelands
• transformation involved irrigation.
• Soil is rarely uncovered for
• extended periods.
• Typically, sufficient water
• available for soil drainage
• Utilization of transported
• water no local drawdown

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• Practices also increase infiltration, reduce
  surface run-off /erosion
• (e.g. mulching, ridges and dyke
• furrows tillage, to increase
• infiltration rates)
• Rangeland transformation not associated with
  intensified desertification.
• Can be argued that irrigated agriculture of
  semiarid region not only averts desertification
  risks but also ameliorates local climate.

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Protected agriculture

• Based on greenhouses
• Especially in hyper-arid zones
• Evapotranspiration minimized.
• Cooling in summers /warming
• on winter nights required.
• Drip irrigation makes
• it feasible.

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Sustainability

• Agricultural production in drylands greenhouses
  intensive, high water/soil space-use
  efficiencies.
• Pressure on soil resources of Israel -- averted
• Requires constant diversification investment
• in research, extension services.
• Diversification necessary to
• meet competition in world
• markets.

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But is it sustainable?

• Does todays agriculture expose land to
  desertification that will appear later?
• 30 years ago the amount of land and water used
  by Israeli agriculture contributed to around 50
  of productivity. during the last decade, land
  and water contributed to only 4 of productivity,
  and 96 of it can be attributed to
  agrotechnologies, research, extension, and
  mechanization, etc (Pohoryles 1999).
• High productivity may not be exhausting natural
  resources nor lead to desertification.
• Yet - only 3.7 labor force
• employed in agriculture,
• Only 2.5 of GDP.

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Water Management Strategy

• Water Carriers 1946 6 inch pipes -- 1 million
  m3 / year
• 1955 Yarkon-Negev (100 million /year )
• 1964 National Water (400 million m3/year)
• Objective
• Agricultural development in drylands
• Winter storage and aquifer recharge.

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Water Management Strategy

• Reservoirs KKL constructed 178 reservoirs,
  largely in semi- arid and hyperarid regions,
  provide 125 million m3/ year, ( 7 of the
  total water in Israels system)
• Objective To improve quality and quantity of
  ground water by
• replenishing and aquifers.
• Impound floodwaters for direct supply to
  irrigation systems in nearby fields.

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Water Management Strategy

• Waste water reuse Effluent reuse 450 Million
  M3/year
• 65 of effluents (300 M3) reclaimed for
  irrigation
• 35 discharged to rivers or sea
• By 2010 Reclaimed Effluents 50 of all water
  to Agriculture
• Objective To expand water supply and eliminate
  hazard.

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Overall Agriculture AchievementFood for 7
million people
Source Central Bureau of Statistics, Israel
Source Kimhi, 2004
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Grazing Policies

• The Law for Vegetation Protection (Goat Damages)
  enacted in 1950. (the Black Goat Law)
• Previously British Mandate prohibit grazing in
  forests
• Focus goats feeding on scrubland major tree
  species.
• Prior to 1948 number of goats
• estimated at 185,000.
• (70,000 sheep
• 14,000 camels in 1943 est.)
• Pre-48 size of Bedouin herds unclear
• (nomadism not constrained by borders.
• No serious inventory.)

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Bedouin Demographics

• Until 1948 nomadic Bedouin tribes lived in
  semiarid and arid lands.
• Population estimates 65,000 to 103,000 at that
  time (Abu-Rabia 1994)
• Extent of Rangelands 10,000 km2
• Economy sheep, goat and camel herding. Modest
  farming
• Seasonal patchwork rainharvested cultivation.
• Dams blocked water and sediment runoff.
• Rainy years, late winter.
• Sustainability Unclear.
• Salinization unlikely result from rainfed
  activity.

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• After war (1950) goat numbers drop to 71,000
  (number of Negev Bedouin drops70,000 to 12,000)
• Pressure on scrubland reduced.
• 1956 - AUMs (Animal Units Month) set according
  to land carrying capacity
• Eastern Mediterranean woodlands reappear.
• Numbers start to yo yo
• - 1973 increased to 115,000
• - 1994 drop to o 70,000
• - 1998 74,000 in 1998

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Environmental Impacts

• Pervolotsky posits positive effects of reduced
  grazing pressure due to resilience of dry
  subhumid Mediterranean woodland ecosystems and
  co-evolution of these systems with human-induced
  disturbances, (i.e., grazing).
• Little quantitative data about soil composition.
• Recently controlled grazing program with KKL
  and Nature/Parks Authority.

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Afforestation Policies

• Amount of lands presently with forests
• -1606 km2 (7 of Israel ).
• Over 260 million trees planted.
• (Over 15 of the dry subhumid and semiarid
  regions of Israel).
• Additional 360 km2 to be added for afforestation,
  115 in semiarid region.

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Afforestation Policies

• Initially began as employment program
• Later rehabilitate degraded lands and prevent
  erosion.
• Planting initially dominated by Aleppo pine Pinus
  halepensis, a circum-Mediterranean species.

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The Jerusalem Pine

• As pioneering species, grows quickly on marginal
  lands rocky terrain, sleep slopes. Withstands
  drought.
• Disadvantages relatively low longevity, low
  resistance to certain parasites, flammability.
• Since 1980s - Planting diversity in KKL
  increases. Indigenous species promoted.

Tabor Oak Tree
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Aforestation Policies in Drylands

• Since 1950s forests created in semiarid areas,
• conventional afforestation techniques.
• 1964 intensification

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Afforestation Policies

• National Master Plan 22 for Forests and
  Afforestation
• Approved in November, 1995 with 25 year
  horizon.
• Plan sets function, legal status and management
  practices in existing and future indigenous,
  afforested and managed woodlands in Israel.

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Aforestation Policies

• Ex. Yatir forest covers 30 km2
• 250-300 mm annual rainfall,
• probably most arid periphery of global
  distribution of Aleppo pine.
• Regarded as a remarkable success of afforestation
  in an area of high desertification exposure and
  vulnerability.
• The Politics of Planting

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Savanazation

• 1986 - afforestation practice, called
  Savanazation, introduced in semi-arid and arid
  regions,
• Based on harvesting surface run-off, through
  whole watershed management in semiarid regions,
  within a precipitation range of 150-250 mm.
• By 1999 23 km2 successfully
• savannized.

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Savanazation

• Contour furrows dug on slopes of watersheds with
  sandy-loessial soils.
• Trees planted at density of 100/hecatre.
• Considerable vertical distance between them.
• The surface between furrows,
• covered by a biogenic soil crust
• - reduces infiltration
• - generates surface run-off
• - collected/infiltrates and
• stored in furrows

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Savannization - Upside

• . - probably reduces flash floods / soil
  erosion,
• - increases overall productivity of semiarid
  soils. (pasture)
• - overall plant biodiversity improves
• - survival in drought years, better than
  rainfall dependent trees
• Savannization Downside
• - Sustainability,
• - aesthetics,
• - hydrological impact debated.

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Impact of Aforestation on Soil

• Precise affect of afforestation/different trees
  on erosion unclear.
• Generally, deters pastoralists, reduces grazing
  pressure.
• Shading effect of trees can help rehabilitate
  indigenous vegetation
• (contributes to soil conservation)
• Improves infiltration of precipitation, soil
  moisture/recharge.
• Israeli dry subhumid indigenous woodlands
  transpire more soil water than dry subhumid
  agricultural lands. (Stanhill 1993)
• (Effect on precipitation - still unclear.)

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Erosion Control The Official Word

• Ten years later the face of the land has become
  rejuvenated its wrinkles smoothed, its scars
  healed, many of its gullies gone. Even, it seems
  the pallid hue of eroded areas has been replaced
  by a healthier color a darker feritle soil. In
  every field, one still discerns traces of the
  uncontrolled flow of water over the years. But
  now, with the aid of different erosion control
  measures, these traces are slowly disappearing
• Soil Conservation in Israel - 1958

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