区域可持续发展与人地关系行为机制模型研究(发展经济学.ppt

1、区域可持续发展与人地关系行为机制模型研究,石 敏俊 筑波大学,区域可持续发展与人地关系行为机制模型研究,区域可持续发展与农业环境政策 人地关系行为机制模型框架的建立：外部社会经济因素影响人地关系变化的机制 鄂尔多斯高原：人地关系行为机制模型与退耕还林对水土保持影响的比较静态模拟 自然科学与社会科学相融合的必要性,区域可持续发展与农业环境政策,欧美国家的农业环境政策 石油农业的化肥农药高投入导致水质污染等环境问题 价格支持政策导致农产品过剩 农业环境政策的核心是推行农业粗放化经营，减少化肥农药投入，减少农产品产量 对于实行粗放经营的农户给予政策补贴,发展中国家的农业环境问题,土地退化引起的农业环

2、境问题 沙漠化，水土流失，盐碱化 环境负荷引起的农业环境问题 水质污染，土壤污染 土地退化的人为因素 人口压力，农业技术水平 依赖资源投入的静态增长导致农业粗放再生产和土地利用的平面扩张，土地利用超过环境容量时带来土地退化,发展中国家的农业可持续发展,解决土地退化问题的出路在于发展可持续集约农业 可持续集约农业：通过集约化达到可持续 集约化：对少量土地实行集约经营，技术密集投入，提高单位土地面积生产力水平，为大面积退化土地休生养息恢复生态、实现区域可持续发展提供条件,保护环境与发展经济的关系,发展中国家的农业环境政策,解决土地退化问题的农业环境政策应当结合发展可持续集约农业来展开 发展可持续集

3、约农业的关键是技术进步，开发实用适用技术 实用：实际农业活动中可应用的技术 适用：适合当地条件适合当地农户采用的技术 发展集约化（技术进步和技术推广）的政策补贴可作为环境保护投资进入环境经济核算,人地关系行为机制模型框架：社会经济因素影响人地关系变化的机制,影响人地关系和环境生态变化的社会经济因素 人口增长 市场和价格变动 技术进步 制度和政策 收入和消费期望 单一或综合的因果关系分析不能阐明社会经济因素影响人地关系变化的机制,Resource Environment,Land Use Agricultural Activity,Institution Policy,Technology,Ma

4、rket Price,Resource Constraint,Impact on Environment,Population growth,外部社会经济环境与人地关系变化,Literature review,Farm household decisions on land use activities and technological choice affect the soil quality and therefore play an important role in aggravating or reducing land degradation process. Farm hou

5、sehold decisions are dependent on relative prices of output, input and production factors, and other socio-economic circumstances that are influenced by macroeconomic and agricultural policy. Agricultural policies affect soil degradation by influencing the level of output, input and factor prices (H

6、eerink, 2001).,社会经济因素影响环境变化的机制,政策和制度外部社会经济环境农户经济行为资源环境变化 反馈：资源环境变化农户经济行为（资源环境退化对经济福利的影响，现在价值与将来价值的关系） 外部社会经济环境变化：价格变动，技术进步，资金和信用约束 政策和制度：经济政策和环境政策，资源分配和资源利用秩序,Conceptual framework,Policy reform,Socio-economic environment,Household decision,Land degradation,Macro and Regional Models,Household and Vil

7、lage Models,Bio-economic Models,Bio-economic household Model,Bio-economic village Model approach,Econometric estimation approach: Lack of consistent data, especially long time series data about effect of soil degradation; Difficult to derive function form of the reduced-form equation. Meta modeling

8、(Decision rule) approach: Estimate a statistical relationship between exogenous and relevant endogenous variables; refer to a black-box representation of relationship between exogenous and endogenous variables;,Bio-economic village Model - continue,Mathematical programming approach: A major advantag

9、e of LP Model is that can combine economic behavior and biophysical process in an integrated framework. Leontief input-output coefficients permits the combination of incompatible economic and biophysical production function. A disadvantage of LP Model is that may generate vast amount of what-if resu

10、lts if some of parameters of the model are not known with great accuracy.,鄂尔多斯高原人地关系行为机制模型,Bio-economic village LP Model Short-term analysis: one year due to uncertainty Village model: appreciate level of analysis Objective function：maximizing benefit of households Production function： Leontief inpu

11、t-output coefficients Consumption function：consumption choice based upon nutrition and prices under constraints of basic nutrition intake demand and hobby Soil conservation process： converted land supply Feedback of soil erosion to production：no feedback process,Bio-economic village LP Model,(1),s.t

12、.,(2),(3),(4),(5),(6),Variable definition,: household discounted utility,: period,: crop,: land type,: land endowment,: the area of crop,produced on land type,in period,: the per unit price of crop or livestock output,: the yield function for production of crop c or livestock v,: a vector of inputs

13、used in production of crop c or livestock v,: the per unit input price for input,Variable definition-continue,: the crop or livestock output,used for self-consumption,: the crop or livestock output,used for self-supply, such as fodder, draft animal,: the production of units of livestock,at period t,

14、: livestock,: the wage level, such as seasonal off-farm wage, constant off-farm wage,hiring labor wage,: the off-farm labor supply of seasonal part-time labor or constant off-farm labor,: the hiring labor supply,: family labor,: family labor input for farm activities,: total labor input for farm act

15、ivities,: discount rate,Modules of LP Model,Processes (73) Production (22): cropping corresponding to land type Corn, Millet, Potato, Sunflower, Rapeseed, Beans, Goat, Sheep, Hog, Cattle Sale (11): Corn, Millet, Potato, Sunflower, Rapeseed, Goat, Sheep, Hog, Mutton, Pork, Wool Self-consumption (6):

16、Corn, Millet, Potato, Beans, Mutton, Pork Purchase (11): Wheat, Rice, Pork, Mutton, Beef, Vegetable, Fertilizers, Pesticide, seeds, Coal Self-supply (5): Seeds, Fodder, Manure, Firewood Resource supply(17): Land supply(6), Labor supply(11) Land degradation (1): Soil erosion,Modules of LP Model - con

17、tinue,Constraints (70) Products (12): Resources (30): land constraints (7); labor time constraints (13); labor allocation constraints (10): family labor (3), hiring labor (7) Balance (25): Nutrition and human demand (10); Farming input (11); Livestock input (4) Rotation (2) Soil erosion (1),Land use

18、 in Ge-zhen-yan Village, Zhunger, Inner Mongolia,The policy measure of converting slope field into forest and pasture started Since 2000, with subsidy of 100kg grain and 20Yuan food-for work per 6.7a,Cropping system and land use,Agriculture and farm economy,Prices of agricultural products,Soil erosi

19、on: EPIC result,Agriculture and land use system,Crop-livestock system: corn-goat-sheep-hog. Corn mainly in flat field for feed and commercial use; millet in terrace and slope field for staple food; rapeseed, sunflower in terrace and slope field for commercial use; potato and beans for self-consumpti

20、on. Field type is most important factor affecting yield. Level of input and technological choice of various crops correspond to field types. Soil erosion modulus differ between field types and various crops.,Farm economy,Smallholders: farm households(12) and part-time households(9). Farm households

21、earn income from crop-livestock activity (livestock income:70%). Part-time households earn most income from off-farm activity(73%). Off-farm job opportunity is limited. Only members of the village can gain right of land management. There is few mobility of land management right.,退耕还林还草政策对水土保持影响的比较静态

22、模拟,模拟结果与现状的拟合比较 农产品价格变动对土地利用变化影响的比较静态模拟结果 退耕还林还草政策对土地利用变化和水土保持影响的比较静态模拟结果 退耕还林还草补贴对土地利用变化和水土保持影响的比较静态模拟结果 非农就业机会对土地利用变化和水土保持影响的比较静态模拟结果,The base run,Households may realize a significant increase in income without increase in soil erosion if they put a much great weight on sedentary livestock by usin

23、g maize and straws as fodder instead of selling maize to earn cash income, and change to grow much more cash crops such as sunflower and rapeseeds in stead of millet. One of probable reason of farmers self-sufficient choice is from constraint of investment. Another probable reason is from farmers ri

24、sk aversion.,Price change and land degradation,Changes in prices of livestock will affect livestock choice, but have no significant effects on land use choice as well as soil erosion. Changes in price ratios of commercial crops affect land use choice, especially land use choice of slope fields, and

25、then have significant impacts on soil erosion. The effects of price change on soil erosion depend on ratio of erosion modulus between concerning crops.,Off-farm job opportunity and soil erosion,Increase in off-farm job opportunities for seasonal part-time labors have few effects on land use activiti

26、es. Increase in off-farm job opportunities for constant off-farm labors will influence land use choice and then land degradation. While the number of constant off-farm labors continues to increase and exceeds over 25 persons, cultivation of millet in slope fields will tend to decrease. As the result

27、, soil erosion will tend to decrease due to withdrawal of cultivation in slope fields along with an increase in off-farm job opportunities.,Land conversion policy and soil erosion,Introducing land conversion policy will affect land use choice of slope fields as well as terrace fields, and concomitan

28、t livestock choice, then have significant effects on reducing soil erosion. Subsidy towards converted slope fields will encourage conversion of slope fields and have significant effects on land use choice, livestock choice as well as soil erosion.,Subsidy and soil erosion,When introducing land conve

29、rsion policy without subsidy, farm income tends to decrease as a cost for combating soil erosion. While allowance of more than 160 Yuan per 6.67a was paid for farmers, soil erosion will be relieved significantly with an increase in farm income. The subsidy for converted slope fields in loess plateau

30、 includes 100kg grain with a price of 1.4Yuan per kg and 20Yuan of food-for work aid per 6.7a, which is equal to 160Yuan per 6.7a.,Conclusion and implication,An integrated bio-economic household model may simulate the effects of change in socio-economic factors on land degradation by involving farm

31、economic behavior within an integrated framework. Mathematical programming approach is useful to develop a bio-economic household model because it can combine farm economic behavior and biophysical process.,Conclusion and implication-continue,The soil conservation program to convert slope fields into forest or pasture is an effective way for combating soil erosion. A reasonable subsidy as compensation tha