Structural adjustment and soil degradation in Tanzania A CGE model approach with endogenous soil productivity
将土壤氮循环模型嵌入坦桑尼亚经济的一般均衡模型，模拟结构调整政策（如减少农业补贴）对土壤生产力和GDP的影响，发现政策组合十年后使GDP提高9%，但土壤退化会抵消超过5%的增长。
In this paper, a model of the nitrogen cycle in the soil is incorporated in a Computable General Equilibrium (CGE) model of the Tanzanian economy, thus establishing a two-way link between the environment and the economy. For a given level of natural soil productivity, profit-maximising farmers choose input levels – and hence production volumes – which in turn influence soil productivity in the following years through the recycling of nitrogen from the residues of roots and stover and the degree of erosion. The model is used to simulate the effects of typical structural adjustment policies like a reduction in agro-chemicals’ subsidies, reduced implicit export tax rate etc. After 10 years, the result of a joint implementation is a 9% higher Gross Domestic Product (GDP) level compared to the baseline scenario. The effect of soil degradation is found to represent a reduction in the GDP level of more than 5% for the same time period.