【作者】 李洁；

【导师】 周应恒；

【作者基本信息】 南京农业大学 ， 农业经济管理， 2008， 博士

【摘要】 在建设社会主义和谐社会过程中,经济发展和环境和谐是当今中国社会发展的主旋律,农业环境问题也是社会主义新农村建设不可忽视的重要环节.农业发展离不开化肥要素投入,但如果这种投入成为农业可持续发展的负担,那么就迫切需要在投入过程中科学合理的约束农业生产行为,运用新理论和新技术引导农民合理高效的施用化肥,缓解目前严重的养分流失问题.集约化种植方式下各种速溶性肥料频繁使用,极易造成降雨与施肥期耦合,引发大量的农田氮、磷径流损失,造成土壤和水域的氮、磷养分富集,形成面源污染,经济发达地区面临的农业面源污染问题更为复杂,且因氮素、磷素发生的不确定和难以量化的特征,加大了监管的难度。尽管已经有不少研究成果对农业面源污染的成因和治理方法进行了有益的探讨,但是大部分研究是从环境学角度出发,对污染的发生和治理进行研究和分析。遗憾的是,从经济学角度出发,对治理农业面源污染的重要可控因素—化肥投入问题进行系统阐述的研究还不多。尤其在目前化肥投入不合理现象日趋严重的情况下,从理论上解释化肥不合理投入的诱因,并选择有效方法约束化肥投入显得尤为紧迫。农户过量化肥投入的诱因必须从市场机制在调整农业投入的外部性问题上存在市场失灵入手,本研究在此基础上剖析农业生产中化肥过量投入问题的原因,揭示化肥投入的外部环境成本,进而对有效控制化肥面源污染提出合理的政策建议。本研究在已有研究的基础上,以经济发达,农业面源污染问题严重的长江三角洲地区为研究对象,分六个主要部分分析阐述了长江三角洲地区化肥过量投入现状、原因及其环境问题的治理方法。第一部分交待文章的理论基础,从理性经济人假设出发阐述市场机制在处理外部性问题上的理论缺陷,提出改变外部性市场失灵的关键是将环境价值以及社会成本纳入农业生产目标函数.第二部分分别从投入强度和投入密度角度描述从1980年以来到2005年长江三角洲地区化肥过量投入现状.第三部分从提高劳动生产率理论入手,分别从要素替代效率角度、化肥的边际产能、要素边际收益和化肥投入对长三角种植业农业产值贡献角度分析农民倾向于选择化肥这种生化型生产技术的经济诱因,指出在追求农业收益最大化的动机下,没有化肥投入的技术和制度约束,化肥过量的投入行为仍将继续.第四部分先从经济理论上分析约束农户化肥过量投入行为必须改变限制农民选择范围的外部条件,即必须改变目前的农业生产成本收益函数,将边际社会成本纳入效益最大化目标函数.然后以太湖地区为例,采用环境影响评价方法计算了太湖地区水稻生产过量氮肥投入引起的环境损失,证明目前化肥的过量使用现象源于现行的农业生产投入函数未能将环境社会成本纳入农业生产函数,造成了对农业生产成本的低估。在此基础上,现阶段应该重新认识农业的生产函数,及时改变以经济效益最大化为目标的农业成本函数,将兼顾环境和经济效益最大化的目标作为未来农业生产的根本.第五部分在前文分析的基础上,从长三角地区经济发展水平,农业结构调整和农产品市场,地权收益的完整和稳定,农业技术水平四个方面分析影响化肥投入环境效果的社会经济因素.通过实证检验证明地区经济发展水平正向促进化肥环境问题的形成,农民情愿用化肥替代价格高昂的土地和劳动要素,不断加大化肥投入加重面源污染。农业结构调整的方向是逐步缩减传统粮棉油产品,增加经济作物的种植,因此瓜果蔬菜等经济作物播种面积比例的增长将引致更多的面源污染发生.土地收益权的完整性和稳定性有利于保证农民对土地的长期投资,增加绿肥、有机肥投入,适当减轻化肥这种短期生产投入,更加关注土壤质量恢复和保障,减少化肥环境问题形成。农业技术水平提高不一定能够起到减少化肥环境问题,如果农业推广的方向是侧重环境友好的农业种植技术,不断提高作物的化肥吸收利用率,那么这种减少作用是存在的,但是另一方面,棚膜技术的发展缩短种植业生产周期,很可能增加化肥用量.第六部分基于第四章至第六章的分析结果,对合理约束长三角的化肥投入提出对策和建议.目前,需要从根本上改变农业生产的成本收益核算体系,将化肥投入的外部环境成本纳入农业成本核算,并辅以加快农村经济发展,提高农民环境意识;保障农民的土地收益权完整稳定;合理调整农业结构,部分地区需要实行限制型农业轮作规定;改革现行农地推广制度和体系,使测土施肥等重要农技手段能够更好的推广发展并为更多的农户所接受.更多还原

【Abstract】 In the process of building a socialist harmonious society, economic development and environmental harmony is one of the main themes in China’s social development. Agricultural environment is also a very important issue in building the New Socialist Countryside Construction. As we know, agricultural development is inseparable from chemical fertilizers, pesticides and other factors of inputs, but if such inputs become burdens of sustainable agricultural development, then to constrain the input of agricultural production within a rational range is very urgent.Intensive cultivation often uses instant fertilizer frequently. If the time of rainfall and fertilization couples, farmland nitrogen will trigger lot phosphorus, runoff loss will happen, resulting in soil and waters of the nitrogen enrichment, which we called non-point source pollution. Developed regions in China will face more complicated agricultural non-point source pollution problems. The uncertain and hard-to-quantify features of nitrogen and phosphorus will increase the difficulty of monitoring the pollution.Despite a number of researches have explored the treatment methods to agricultural non-point source pollution, most of the studies are from the perspective of environmental studies. Unfortunately, there are few researches which from the economics point of view to analysis the very important controllable factors-fertilizer inputs of the agricultural. Especially in current circumstances that the fertilizer input is unreasonable aggravating, to explain the incentives of fertilizer over-investment, and to choose an effective method to restraint the over-investment is particularly urgent.External farmers’ market failure is the cause of excessive fertilizer inputs. On this basis, this study profound analysis the deep-seated reasons of the excessive fertilizer inputs in Yangtze River delta, accounting the external environmental costs of chemical fertilizer, then give the reasonable policy recommendations on controlling the non-point source pollution by excessive chemical fertilizers. Being based on the existing researches, this study targeted at the Yangtze River Delta region whose economy is prosperity and agricultural non-point source pollution is serious. There are six main parts in this research. The main contents include: the excessive fertilizer inputs status of Yangtze River Delta region, the reasons for environmental problems and their methods of governance.PartⅠ, chapter two, the theoretical foundation of this article is given by the the first part. From the point of rational economic assumptions, this part described the market mechanism in dealing with the issue of external defects in theory, and then proposed that the key point of changing the situation of external market failure is to include the environmental and social costs into the value of agricultural production target function.PartⅡ, chapter three, It descrips the excessive fertilizer inputs status from the perspective of strength and density of the fertilizer input from 1980 to 2005 in Yangtze River Delta region.PartⅢ, chapter four, from the perspective of improving labour productivity, it analysis the substitute rate of other elements which can replace fertilizer elements, the marginal production of chemical fertilizers, the marginal factor income of chemical fertilizers, as well as the contribution to agricultural production value of fertilizer input on the Yangtze River Delta fanning. Through the above analysis, it can explain the reason of the economic incentives by farmers who tent to choose the fertilizer production technology instate of other elements technology. It point out that under the condition of pursuit of agricultural revenue maximization, if there is no restraint technical system to the fertilizers input, the excessive fertilizer inputs situation will continue.PartⅣ, chapter five, theoretical analysis the way to bound farmers’ fertilizer inputs through change the external conditions in farmers choose process. The key point is to change the current cost of agricultural production revenue function, include the marginal social costs into the function to maximize the agricultural income. Then take the example of Taihu Lake; it calculated the environmental damage by excess nitrogen fertilizer use in Taihu Lake area for rice production by environmental impact assessment methods. It is proved that the current excessive use of fertilizers is the result of underestimated the cost of agricultural production. At the present, the objective function of agricultural production inputs hasn’t included the environmental costs into agricultural production function. At this stage, it should be a new awareness of the agricultural production function. It should change the agricultural cost function to maximize economic efficiency into an agricultural cost function to maximize environment and economic efficiency objectives as a fundamental solution.PartⅤ, chapter six, empirical analysis the effects of socio-economic factors on the environmental effects of fertilizer inputs. The impact of the four most important factors has been tested in this part, which are Yangtze River Delta region’s economic development level, the agricultural structure and agricultural markets, the integrity and stability of the right of land. Empirical analysis of the results show that the level of economic development forward in promoting the formation of fertilizer environmental issues, farmers use fertilizers to substitute the high cost of alternative elements such as the land and labor, which will increase the possibility of environmental pollution, because the adjustment of agricultural structure direction is to gradually reduce the traditional grain, cotton, oil products, increase the cultivation of cash crops, which will lead to more non-point source pollution occurred, the integrity and stability of the land revenue will ensure the farmers long-term investment incentive on the land, farmers will increase green manure and organic fertilizer inputs, appropriate to reduce the production of chemical fertilizers such short-term investment, give more attention to the restoration and protection of soil quality, these all will reduce fertilizer environmental issues formed, agricultural technological progress may not be a reduction of fertilizer environmental issues, If the use of agricultural machinery can increase fertilizer efficiency, then the role is existed, and because the agricultural plastic film technology can shorten the development cycle crop production, it is likely to increase the amount of fertilizer.PartⅥ, chapter seven, policy suggestion of controlling fertilizer inputs based on former analysis. First of all, to change the agricultural production of cost-benefit accounting system fundamentally, the external environmental Fertilizer inputs costs should be take into agricultural cost accounting. At the same time, some related socio-economic policies can not be ignored. Accelerate the development of the rural economy and improving their environmental awareness can reduce the occurrence of fertilizers environmental pollution problems. Reasonable adjustment of agricultural structure must be guaranteed, and some areas need to implement restrictions on agricultural crop rotation. Reform the existing system and the promotion of agricultural land system so that the soil testing, fertilizer, and other important agricultural technical means to better promote the development of the rural households and more acceptable.更多还原