Sustainable Agroforestry in Degraded Drylands: Win – Win Approaches for Local, Regional and Global...

Sustainable Agroforestry in Degraded Drylands:

Win – Win Approaches for Local, Regional and Global Problems

Leu S. and Mor-Mussery A.

in collaboration with the Sustainability Laboratory

Overexploitation Land Degradation by

-Productivity

-Carbon Stocks

-Biodiversity-Resilience and Sustainability Mismanagement

Acceleration of and Sensitization to Effects of Global Warming

2. Rehabilitation by Restoration of Vegetation

Productivity+

Carbon Stocks+

Biodiversity+ Resilience and Sustainability+ Management

Mitigation of and Adaptation to Effects of Global Warming!

Engineering or Forestry

Topography Analysis and Engineering RequirementsN

Site plan

Riverine, native plants

*Plants the will be suited in the edges of the river

Silvipasture

Savanna trees with additional uses (mainly pasture), suited to arid zones,

Shade trees

The shade pathways

Fenced Green Tree

To border between the different fields and supplement extra use (crop, pasture, shade

etc…)

• The area excluded by the black line is unsuitable for large agricultural plots, while areas 1 – 4 do not pose any problems except for small corrections along the river;

• The following pictures demonstrate these facts;

200m

Only the two marked rhomboids are suitable for agriculture, about 10 and 5 dunam;

Stable Wadi

Unstable Wadi

and Soil

Large Rocky Slope with Wadis

The Soil in the southern-most Wadi is highly erosive; these erosion structures have to be stabilized by terraces, planting of

mixed trees, olive plantations and high value trees; Native trees will be incorporated for high grazing value, biodiversity and

agricultural return;

Technique1: Restoration of vegetation, erosion control and tree planting using contour drip irrigation

Trees and Shrubs were planted along drip irrigation, every 2m one line was established, and every dripper received 100L of water

during November-December 2008.

The number of functions fulfilled by dryland trees is huge• Carbon Sequestration into biomass;

• Recovery of nutrients from deep soil;

• Enrichment and protection of top soils by plant litter;

• Increasing productivity of annual vegetation;

• Preventing wind erosion;

• Providing shade to animals and buildings;

• Preventing water runoff and erosion;

• Restoring natural habitats and biodiversity;

• Providing fodder during the dry season;

• Providing biomass energy;

• Providing high value oils and fruit for economic expansion;

Technique2: Restoration of land using dryland trees

20 years old Acacia victoria woodland near Yattir farm (220 mm

mean Annual Precipitation)

2.5 t per ha and year annual vegetation;2.5 tons per ha and year tree litter (edible);1 ton per ha and year woody biomass;6 tons per year CO2 sequestration;Supports 2 goats per ha:

RICH ANIMAL LIFE

Degraded land nearby:

0.5 t per ha and year annual vegetationNO tree litter!NO woody biomass!NO CO2 sequestration!Supports 0.2 goats per ha

NEGLIGIBLE ANIMAL LIFE!!!

*Problem: Acacia victoria is not a native species!

Fact: Woodland trees Sequestrate high Carbon amounts into biomass

Biomass, slope trees

0

5

10

15

20

25

30

35

40

45

Total Litter Weeds

g p

er

600cm

^2

canopy

open

Facts: Grazing Improvement, Land Rehabilitation and Biomass Production by Silvipasture

Biomass and Litter under Tree Canopy and in nearby Open Areas:

Suitable Trees Promote Growth of Annual Vegetation and Provide Extraordinary Amounts of Organic Litter!

Facts: Using trees for agriculture purposes in arid environments

Left: niche of wheat growing without need of irrigation and nutrient supply;

Right: Small olive tree survives inside the Acacia victoria woodland, taking advantage of higher soil fertility and humidity, reduced

evaporation and protection from wind by the other trees .

planting techniques: The planting method dramatically affects soil characteristics

Contour Trenching Planting without Soil Disturbance

0

0.5

1

1.5

2

2.5

3

Savanna Open Contour Open Savanna Canopy Contour Canopy

SO

C (

%)

Terrace Agroforestry using Natural Topography

A simple stone terrace suffices to create excellent conditions for Olive cultivation. The reduced water runoff intensity allows natural vegetation to recover as well.

Intercropping in Agroforestry Terraces

Other Crops Used for Intercropping:

• Vegetables• Watermelons• Sunflowers• Tobacco

Classical agroforestry with summer sorghum (left behind) intercropped with olive trees. The humidity stored in the soil of the dammed areas suffices to maintain growth of sorghum throughout the hot, completely dry summer.

An area covered by manure (right) displayed very significant plant growth in spite of very poor rainfall (~110 mm in 2009), in contrast to the

exposed soil to the left.

Principle of Soil Management:THE MOST IMPORTANT:Exposed Soil Degradation

Expected Benefits at Wadi Attir

• Carbon sequestration compensating for the agricultural greenhouse gas emissions.

• Water savings by optimized agricultural production, wind breaks, plant litter and no till agriculture;

• Reduced fertilizer use due to nitrogen fixing plants and nutrient recovery from deep soil by trees;

• Improved biodiversity due to planted native trees;• Increased profitability due to growing amounts of

high quality high price oils;• Providing waste biomass for energy production from

tree trimming; • Reduced erosion and soil loss due to terrace

agroforestry and erosion barriers;