1. Assessing SLM strategies at regional scale Luuk Fleskens Sustainability Research Institute, School of Earth & Environment University of Leeds, UK Mike Kirkby, Brian Irvine School of Geography, University of Leeds, UK
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3. SLM strategies can tackle land degradation Technologies need to be targeted to the problem at stake and tested Scale of application is usually at the local field level However, experimental research is unfeasible for regional assessment DESIRE develops a model for regional assessment of local SLM solutions
4. A number of promising SLM strategies is selected Assessment and selection of SLM technologies and approaches in DESIRE: a 3 step process I. Identification II. Assessment III. Selection See the DEMO on this process
5. The PESERA-DESMICE modelling framework PESERA : Grid-based regional scale soil risk assessment model (grid 0.1 – 1 km), modified to take into account effect of various SLM strategies and other degradation types DESMICE : New model scaling up SLM feasibility assessments from local to regional level using spatially-explicit financial cost-benefit analysis Combined, these models can assess effects of policy scenarios on uptake of SLM and mitigation of land degradation
6. Applicability limitations are defined for selected SLM strategies SPA01 Reduced contour tillage SPA04 Boqueras water harvesting Soil depth Land use Distance to stream Slope Applicable Landform Not applicable Aggregate applicability
7. Case 1: applicability limitations for Torrealvilla catchment, Murcia, Spain SPA02 Vegetated earthen terraces SPA01 Reduced contour tillage SPA04 Boqueras water harvesting SPA03 Organic mulch under almond trees SPA05 Organic almond/olive production
8. Case 2: applicability limitations for Oum Zessar catchment, Tunisia TUN09 Jessour TUN10 Gabion checkdam TUN11 Rangeland resting TUN14 Recharge well TUN12 Tabia TUN13 Cistern
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10. Biophysical effects of SLM strategies are simulated: TUN11 The effect of resting grazing land is simulated by an increased level of biomass. Grazing animals remove a significant part of the vegetation, thereby exposing soil to degradation risk. In non-grazed areas vegetation re-establishes itself reducing in turn the susceptibility of soil to water (and wind) erosion. TUN11 Rangeland resting Net effect (in kg m -2 ) on average vegetation biomass of resting grazing land (TUN11) vs. a without case of 30% of biomass being grazed, Oum Zessar catchment, Tunisia
11. Spatial variability in investment costs is considered Variable input quantities (environmental factors) Variable price of inputs (market/transport factors) e.g. as a function of slope options to take into account topography, transport type, infrastructure, etc.
12. Spatial variability in investment costs is considered: TUN11 The standard cost reported for TUN11 is 50 US$ ha -1 for fencing. An allowance was made for transport costs of fencing material (up to US$3.36) and slope (up to US$3.00). The resulting map of investment costs ranges from US$ 50.11 (blue) – US$ 54.91 (red) TUN11 Rangeland resting
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14. Presentation Rabat, 23 rd October 2009 Without case TUN11: Rangeland resting Rangeland provides fodder, the equivalent of which needs to be purchased if rangeland resting is applied. We assume here that the benefits from rangeland resting can be obtained in the fourth year after investment, after which productivity falls back to without case level. Cash flow series are constructed for each grid-cell: TUN11 Y INV MAI PRO 0 -52 - - 1 - -5 0 2 - -5 0 3 - -5 0 4 - - 200 Y INV MAI PRO 0 - - - 1 - - 20 2 - - 20 3 - - 20 4 - - 20 The economic life of technologies is basis for the comparison
15. Technology options Presentation Rabat, 23 rd October 2009 Financial cost-benefit analysis is performed for each technology Spatially- Explicit Net Present Value (NPV) Potential adoption (based on profit maximisation) Valuation of cash flows over same time horizon and discount factor
16. Presentation Rabat, 23 rd October 2009 NPV of rangeland resting (US$ ha -1 ) Oum Zessar catchment, Tunisia Financial cost-benefit analysis is performed: TUN11 Employing a discount rate of 10%, the cashflow series for rangeland resting lead to negative Net Present Value (NPV) in the whole area where the technology is applicable, ranging from -90 US$ ha -1 to -50 US$ ha -1.
17. Presentation Rabat, 23 rd October 2009 Once previous steps have been done scenario analyses are possible NPV (US$ ha -1 ) of rangeland resting after accounting for subsidies The Tunisian Government has put subsidies on the practice of rangeland resting. A 30 US$ ha -1 contribution towards fencing and a 70 US$ ha -1 maintenance payment to cover fodder purchases. According to these preliminary analyses, the low productivity of rangeland and height of the maintenance payment are not in balance. NPV of rangeland resting (US$ ha -1 ) Oum Zessar catchment, Tunisia
18. A. Policies affecting farmer’s valuation of effects Presentation Rabat, 23 rd October 2009 Different types of policy scenarios... But : overruling farmers’ profit maximisation (negative returns?) or applicability limits (environmental risk?) B. Policies enforcing adoption of technologies But : perhaps no technology that delivers the target! C. Policies stimulating/ enforcing environmental targets
19. Presentation Rabat, 23 rd October 2009 ...and other analyses that PESERA-DESMICE can handle Cost-effectiveness analysis: comparing cost of technologies with physical effects
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