1. 1 Tradeoff analysis and NUTMON: Linking models for policy analysis A.P Mora-Vallejo, J.J. Stoorvogel, J. Antle, A. de Jager, C. Crissman

2. 2 Background NUTMON studies provide a clear characterization of present farming systems and have guided the targeting of integrated nutrient management interventions at the farm level. Though several INM techniques have been proposed and encouraged locally, effective implementation of agricultural policies to support these new technologies is still lacking. We linked the NUTMON toolbox to the Tradeoff Analysis Methodology (TOA) in order to draw conclusions from nutrient budgets in Africa and move the discussion in the direction of effective intervention and policy making.

3. 3 FARM SELECTION FARM SURVEY Clean up, analysis, debugging CLEAN FARM DATA NUTRIENT BALANCE CALCULATIONS RESULTS LITERATURE AND ANALYSIS DATA STAKEHOLDER MEETINGS FARM SURVEY MODEL ESTIMATION SCENARIO ANALYSIS ENVIRONMENTAL IMPACT MODEL TRADEOFFS RESULTS LITERATURE GIS DATA (soil, climate) NUTMON processTOA process 1 Priority setting 2 Farm data 3 Simplified model

4. 4 The Machakos Case Machakos application has been carried out as a first attempt of TOA in SSA It is a case study to solve technical issues of the model in a new environment It is an application to call attention of local policy makers and researchers for further development in the region

5. 5 Machakos Study Area

6. 6 1. Machakos 2. Kionyweni 3. Kasikeu 4. Kiomo 5. Matuu 6. Kibwezi

7. 7 1. Machakos 2. Kionyweni 3. Kasikeu 4. Kiomo 5. Matuu 6. Kibwezi

8. 8 1. Machakos 2. Kionyweni 3. Kasikeu 4. Kiomo 5. Matuu 6. Kibwezi

9. 9 Inherent Productivities Farmers’ expected output for the growing season is an important driving factor behind their decision making process The output is a function of the inherent land qualities and current land management in a particular field Calculated with crop growth simulation models from the DSSAT Given the complexity of mixed farming systems, crop system were used in the analysis such as mixed, maize, vegetables, grass, maize & beans.

10. 10 Model Estimation Inherent productivities are then used to estimate the econometric production model that describes the farmers’ decision making process Explains the variation in management practices for the different crops based on soil and climate.

11. 11 Spatial data vcodeclimatesoil

12. 12 Nitrogen depletion (kg ha -1 year -1 ) vs Net Returns (KSh ha -1 ) for a single TOP in a base scenario (aggregation by farm)

13. 13 Nitrogen depletion (kg ha -1 year -1 ) vs Net Returns (KSh ha -1 ) for 5 TOP and 3 scenarios (aggregation by TOP)

14. 14 Mapping TOA results

15. 15 Conclusions NUTMON is an excellent source of data for TOA applications Time consuming data gathering for TOA can be greatly decrease by using NUTMON data sets The framework of NUTMON and TOA are perfectly complementary