Status of Soil Resources in Lebanon By Roger FRANCIS CNRS-National Center for Remote Sensing Jordan Amman 1-5 April 2012
Status of environment and coastal ecosystem State of the art on soil studies in Lebanon Early soil studies in Lebanon addressed: Soil mapping with the reconnaissance soil map of Lebanon at 1:200.000 scale (Geze, 1956), Pedogenesis of red soils on hard limestone (Lamouroux, 1968), Soil irrigability and fertility (FAO, 1969) using the old French soil classification. Further studies targeted: Soil toposequence in arid climate (Verheye, 1973) Soil formation on basalt (Osman, 1974), Genesis of calcareous soils (Tarzi and Paeth, 1975), Phosphorus retention (Ryan and Ayubi, 1981), Mineralogy of Lebanese soils (Darwish et al., 1979; Sayegh et al., 1990) Mountain soil formation and genesis (Darwish et al., 1978; Darwish
More recent soil studies addressed: Soil salinity on the southern coastal strip (Solh, 1987), Causes and impact of soil salinity on the Lebanese coast (Atallah et al., 2000; Atallah et al., 2009), Soil vulnerability to erosion with GIS models (Bou Kheir et al., 2001), Descriptive soil erosion within two Lebanese watersheds (CoLD, 2005), Land degradation (Zurayk et al., 2001; Darwish et al., 2004; Youssef et al., 2009; Darwish and Faour, 2008), Soil vulnerability to desertification for NAP to combat desertification in Lebanon (Darwish, 2003), Nitrate and heavy metal pollution risk and status (Moeller et al., 2003; Nsouli et al., 2004; Darwish et al., 2008; Francis et al., 2011), Pesticide adsorption and degradation on soil particles (Thomas et al., 2005), Soil resilience and the adaptation of agricultural sector to climate change (Hamze et al., 2010),
Soil information updated with : - Digital soil map of Lebanon at 1:200.000 scale (Darwish et al., 2002) - Creation of the new soil map of Lebanon at 1:50.000 scale (Darwish, 1999; Darwish et al., 2006) FAO-UNESCO, WRB legends and USDA soil taxonomy BAALBACK JEZZINE
Monitoring the status of land degradation in Lebanon Several natural and human-induced factors contributed to land degradation in the country: Natural Rugged topography with 64% of territory having complex landform with sloping and steep slopes, Old deforestation, Poor drainage, Weak lithology, Torrential rainfall. All these factor cause: Flash floods Erosion Mass movements and landslides
Human induced Forest fires Chaotic urban sprawl amplify the negative impact of deforestation. Inappropriate irrigation practices and fertilizer application secondary soil salinization. Improper practices also lead to deterioration of groundwater quality and soil contamination hazards.
Urban encroachment on arable lands 1. At the national level Urban expansion over different lands in Lebanon Landform Urban area by category, ha % of area Level land 40.992.12 17.91 Rolling 23.991.3 13.3 Slopping 33.820.12 12.01 Steep 29.204.62 12.31 Very steep 6.050.17 11.61 Karst 756.86 2.073 Urban sprawl into different lands in Lebanon (Landsat 2005)
Recent urban sprawl 2000-2010 A total loss of 30800 ha of productive lands Land capability classification for Lebanon Class Productivity Km 2 % I High 313.36 03.09 II medium 1346.61 13.27 III low 2958.24 29.14 IV Very low 3882.13 38.24 Soil aptitude to agriculture V Non arable 1650.53 16.26
2. At the regional level Land cover/use of Tripoli area in 1964 Urban sprawl on productive lands in 2000 Classes Surface 1964 (ha) Surface 2000 (ha) (ha) Change Horticulture 928 581-341 -36.7 Olives 3055 2121-934 -30.6 Forests 32 137 +105 +328.1 Shrubs 133 246 +113 +84.9 Grassland 333 318-15 -4.5 Non productive lands 769 92-677 -88.0 Urban area 722 2223 +1501 +207.9 Total area 6053 6053 - - %
Impact of quarrying practices on land resources Multi temporal analyses of landsat images and Ikonos between 1996 and 2005 revealed: Nbr quarries increased from 711 to 1278 Quarried area increased from 2875 to 5283 ha. Modeling the risk of abandoned quarries on land resources in Lebanon using parameters like: Slope, Climate, Previous vegetation cover, landuse, Soil and rock types Groundwater 65.9% moderate impact 8.2% high impact
Soil erosion Potential soil erosion as a function of soil characteristics: - Soil depth, - Soil structure, - Soil texture, - Organic matter content, - Structural stability, In relation to: - Geomorphology - Climatic conditions
Soil salinity Evolution of soil salinity in a semi arid Lebanese region between 1997 (El Khatib et al., 1998) and 2000 (Darwish et al., 2005) Level of salinity ds/m Year of observation Non saline <2 Very slightly saline 2-4 Slightly saline 4-8 Saline 8-16 1997 2000 1997 2000 1997 2000 1997 2000 Proportion % 35.3 15.9 23.5 30.1 31.4 39.3 9.8 14.7 Number of samples 75
Soil pollution Nitrates in the soil and soil solution Depth distribution of soil nitrate (Nmin) as a function of different land use Depth [cm] 0-50 50-100 100-150 150-200 200-250 250-300 300-350 350-400 400-450 450-500 grain-potato rotation apricot tree plantation vegetable cultivation 0 20 40 0 50 100 150 200 250 300 0 Extractable Nitrate [mg/kg soil] Depth [cm] 60 80 100 120 140 160 180 200 0 50 100 150 200 250 300 350 Nitrate [mg kg -1 ] December 2001 March 2002 September 2002 December 2002 February 2003 Depth [cm] 200 0 50 100 150 200 250 300 350 400 Accumulation of soil nitrate in different land use in fall and leaching by spring 50 100 150 Nitrate [mg kg -1 ] December 2001 March 2002 August 2002 November 2002
Nitrate contamination of groundwater Heavy metals in the soil-nickel Central Bekaa. Soil Protection effectiveness
Intensive agricultural practices on the coastal area In greenhouses on the coastal area, a steady increase in the ECe from 0.4 ds.m -1 to 15 ds.m -1 was observed (Solh et al., 1987) and explained by poor soil leveling. However, soil salinity rise up to tenfold inside the greenhouse compared to outside soil. This was associated with excess input of fertilizers (Atallah et al., 2000) and use of saline water in irrigation and Chlorine accumulation in the soil (Atallah et al., 2009). Log ECe 1.80 1.60 1.40 1.20 1.00 0.80 0.60 0.40 0.20 0.00 (Source: Atallah et al., 2000) Frequency of distribution of soil salinity inside compared to initial soil salinity outside the greenhouse on the coastal area y = 0.6117 x R 2 = 0.7591 0.00 0.50 1.00 1.50 2.00 2.50 Log Cle
Soil information and national soil monitoring capacities Cover Scale Theme Date Type of spatial object Author Provider Format GIS 1, Paper 2 Available soil information on the Lebanese Republic Soil 1:200.000 Soil 1:20.000 and 1:50.000 Reconnaissance soil map of Lebanon Soil suitability for irrigation. In scattered areas Soil 1:200. 000 Soil Mineralogy 1956 1969 Late 70 s published in 1990 Soil 1:50.000 Soil Families of 1973 Soil 1:50.000 Detailed soil map 2006 Soil 1:200.000 Soil erosion 2002 Soil 1:200.000 Soil Pollution 1:50.000 Soil desertification index Heavy metal pollution, in Central BeKaa 2002 1999 and 2004 Polygons and report Polygons and report Polygons and report Polygons and report Polygons Database Polygons Database Polygons Database Polygons Database Bernard Geze MoA 1, 2 UNDP, FAO A. Sayegh et al. LARI 2 CNRS 2 W. Verheye CNRS 2 T. Darwish et al. T. Darwish et al. T. Darwish et al. T. Darwish et al. CNRS 1, 2 CNRS 1, 2 CNRS 1, 2 CNRS 1, 2
Challenges and capacity building Conservation of diverse Mediterranean soil of Lebanon from: Sealing Salinity Contamination Erosion Quarrying Bioremediation to remove salts from the soil using a sequence of tolerant crops (El Moujabber et al., 2006). A clear national policy aiming at the conservation of Lebanese productive lands and the promotion of rural development and agricultural activities. Promote research to estimate future farmland requirements in densely populated coastal areas.
Challenges and capacity building (Cont.) Reconsider current policy and legislation licensing the new quarries in Lebanon. The need to accomplish the descriptive erosion mapping at remaining watersheds to elaborate a draft management plan and sets a series of indicators. Elaborate curative and protective measures to monitor the progress made by the stakeholders at national (government) and local (municipalities, NGOs) levels. Disseminate good agricultural practices and awareness is a national priority to protect soil and groundwater from salinity. Accomplish the heavy metal content in Lebanese soils. Assess soil quality nationwide to control crop cultivation on suitable land quality. Elaborate and implement landuse planning to protect arable lands.
Conclusion Absence of clear policies and regulations to protect soil resources. Chaotic urban expansion results in soil irreversible loss. Observed mismanagement of fertilizer and water inputs leads to soil salinity and contamination. No policies based on land capability and suitability Lack of incentives to agricultural land use systems Absence of control of the quality of imported fertilizers (heavy metal content). Need to establish collective irrigation schemes notably on the coastal area Disseminate the research results and promote know how transfer to farmers to overcome the weakness of participatory management of land degradation in the country. Increase the number of associated research units supported by CNRS to eradicate the waste of resources and efforts caused