Tradeoffs Model Feb 2005

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Department of Geography
There is increasing demand for tools that provide insight into complex nature of agricultural systems that deal with a broad range of sustainability issues related to policy intervention, technological innovations, and changes in environmental conditions such as global warming. This derives from the fact that sustainable agricultural production is a critical component in a strategy to combat both poverty and environmental degradation. Soil degradation continues to be a key factor in unsustainable production systems, despite decades of research on soil conservation and other sustainable practices. The dominant economic explanation for continuing trend towards natural resource degradation in many parts of the world is that existing economic incentives often encourage degradation and discourage conservation. The foregoing scenario shows that the challenges facing researchers and policy analysts are to understand the factors and processes causing the use of unsustainable practices, and how to design mechanisms that will provide farmers with incentives needed to adopt more sustainable land use and management practices. An understanding of inherent economic and environmental tradeoffs in some of identified sustainable land use and management practices provides an opportune entry point towards design of mechanisms that will provide incentives needed to adopt more sustainable production systems. A key component of many unsustainable agricultural systems is degradation of soils through loss of soil organic matter (SOM). When soil is put into cultivation, associated biological and physical processes result in a release of soil organic carbon (SOC) over time, often 50% or more, depending on soil conditions and agricultural practices. Consequently, there is potential to increase SOC in most cultivated soils. Many management practices have been demonstrated to increase SOC, including incorporation of crop residues, and increases in cropping intensity and fertilization. Given that farm households in degraded environments are predominantly subsistence in their production, and generally resource-poor, incentive mechanisms aimed at meeting environmental management objective of carbon sequestration in agricultural soils could concurrently contribute to the goals of alleviating rural poverty, enhancing agricultural sustainability, and mitigating greenhouse gas (GHG) emissions. Past and on-going biophysical studies have been able to identify and demonstrate organic based soil fertility management practices, with modest applications of mineral fertilizers that would concurrently lead to improvement in soil organic carbon (SOC) levels, nutrient loss amelioration and improved agricultural productivity. Management practices that could add 4 T C ha,l y(l and between 100 - 300kg N ha,l through atmospheric nitrogen fixation by the legumes in the system have been demonstrated. The proposed Ph.D. study intends to employ Tradeoffs Analysis (TOA) Model (an integrated GIS-based bio-physical and economic modelling system) to assess the sustainability of agricultural production in the smallholder farming systems of central Kenya highlands (CKH) to meet desired economic objective of enhanced productivity and environmental objective of enhanced soil carbon sequestration under an array of soil management technology scenarios. The objectives of the study are to: (i) develop production models to estimate inherent productivity of alternative soil management technology scenarios under study, (ii) develop environment process simulation model to estimate soil carbon sequestration impacts of alternative soil management technology scenarios, (iii) develop econometric process simulation model describing decision making process of farmers in terms of incentives to adopt alternative soil management technology scenarios, and (iv) integrate outputs of objectives (i) through to (iii) to quantify economic and environmental tradeoffs associated with alternative policy and soil management technology scenarios. The study will be implemented in Ministry of Agriculture managed National Agriculture and Livestock Extension Program (NALEP) focal areas in Kariti village of Maragwa district and Mukanduini village of Kirinyaga district in Central Kenya Highlands. It is anticipated that the study results will help to develop a decision support system capable of quantifying tradeoffs between key sustainability indicators under alternative policy and technology scenarios in smallholder production environment.