【作者】 高春雨；

【导师】 邱建军；

【作者基本信息】 中国农业科学院 ， 作物生态学， 2011， 博士

【摘要】 农田N₂O是重要的温室气体排放源,农田N₂O减排是农业减排的重要组成部分,农业碳贸易是推进农田减排的有效途径。本文在分析华北旱地农田氮肥施用与减排潜力的基础上,建立了基于县域尺度的农田N₂O排放量估算及测土配方施肥减排N₂O碳贸易方法学,以山东省淄博市桓台县为例,运用DNDC和IPCC两种方法估算该县农田N₂O排放量,并进行农田测土配方施肥减排N₂O碳贸易量测算案例研究,最后选择Logist模型研究农户降低施肥量的意愿。主要研究结论分述如下:（1）以黄淮海为例,研究了减量施氮、施用缓释肥料、硝化抑制剂的减排潜力及实施可行性。氮肥施用是农田N₂O的重要排放源,N₂O排放量一般为肥料用量的0.1%～2%。我国的氮肥施用量大,以黄淮海区域为例,1990～2008年间,氮肥施用量年均增长3.12%,单位播种面积施氮量达到了217.4 kg/hm2,是世界平均水平的3.3倍,而氮肥利用率很低,只有30%～35%。减量施氮、施用缓释肥料、施用硝化抑制剂可以有效地减少农田N₂O的排放量,减排潜力分别达到了6%～30%、10%～40%、20%～83%之间。实施测土配方施肥工程,可有效减少农田N₂O排放,同时增加农民收入,从经济和技术上都是可行的;而缓释肥料和硝化抑制剂受技术、成本、产品特性等方面的限制,需要更充足的试验和技术改进。（2）按照CDM方法学基本组成框架构建了农田N₂O减排的碳贸易方法学。IPCC方法和DNDC过程模型法是估算区域农田N₂O排放的两种重要方法,IPCC是基于氮素投入与排放系数为基础进行计算,DNDC模型通过模拟硝化反硝化过程来计量N₂O的排放量。相比而言,DNDC模型法科学表征了农田N₂O排放的时空差异性。目前,农田N₂O减排还没有相应的CDM项目方法学,本研究依托DNDC模型、测土配方施肥技术,建立了农田N₂O减排碳贸易方法学,项目边界为农田及化肥生产企业生产过程,基准线为常规施肥农田N₂O排放及化肥生产耗能,项目线为实施测土配方施肥条件下农田N₂O排放量及化肥生产耗能。此外,还规定了泄漏,并制订了相应的监测计划。（3）以乡镇为基本单元,运用IPCC和DNDC方法估算了2008年桓台县农田N₂O排放。IPCC方法估算的排放总量和单位耕地面积排放量分别为76.02t和3.01kg/hm2,DNDC模拟结果分别为59.6t和2.36kg/hm2,前者比后者高27.6%;DNDC模型模拟结果表明,玉米-小麦轮作系统是桓台县农田N₂O的主要排放源,占排放总量的85%,蔬菜占9.28%,棉花占4.7%,大豆、花生、土豆合计只占0.5%。比较而言,DNDC是基于氮循环过程而建立的N₂O估算模型,考虑了土壤、气候管理措施等对农田N₂O排放量的影响,估计结果更加符合农田N₂O的实际排放量。（4）基于已建立的县域农田N₂O减排CDM方法学,撰写了桓台县农田N₂O减排的项目设计文件（PDD）。结果表明,通过实施测土配方施肥项目共实现温室气体减排2.65万t CO2,其中农田减量施肥共减排0.935万t,占25.3%;减少氮、磷肥所引起的化肥生产企业节约能耗1.54万tCO2和0.18万t,分别占58.3%和6.8%;而钾肥生产则增加排放0.011万t。分乡镇看,索镇镇、起风镇的减排量最大,达到0.48万t和0.62万t;田庄镇、荆家镇、陈庄镇、新城镇、周家镇、果里镇得减排量在0.17～0.23t之间;而邢家镇、马桥镇、唐山镇的减排量较低,在0.2万t以下,各乡镇排放量的大小是由施肥量的大小和耕地面积所决定的。（5）采用分层抽样对桓台县7个乡镇、190个农户的施肥量及降低施肥的意愿进行研究。结果表明,在被调查的施肥过量农户中,只有20.8%的农户愿意降低施肥量,76.6%的农户根据习惯或化肥经销商的推荐确定施肥量,70.9%的农户不知道过量施肥对大气、水体和农产品会产生污染。说明农户施肥是比较盲目的,缺乏相应的技术指导。运用Logist模型对农户降低施肥量的意愿进行研究,结果表明,农民文化程度、耕地面积、对化肥是否过量的认识、总收入、种植业收入比重对农户降低施肥意愿影响显著,除种植业收入比重外,其他均为正向影响。降低施肥量的情景研究表明,技术推广、试验示范、补贴及法规或政府部门规定等是促使农户降低化肥施用量的有效方式。更多还原

【Abstract】 N₂O was an important greenhouse gas（GHG）and its mitigation was the main part of agricultural GHG mitigation. Agricultural carbon trade was an effective way for promoting agriculture GHG mitigation. Based on analyzing the nitrogen fertilizer application rate in upland and the potential for reducing emissions in North of China, this paper, taking Huantai county, Zibo city, Shandong Province as an example, applied IPCC method and DNDC model to estimate N₂O emissions from cropland at county scale, and then established a methodology of N₂O mitigation carbon trade from soil testing and fertilizer recommendation project. At last, the farmer’s willingness of fertilizer reduction was investigated based on the Logist model. The main conclusions were as follows:（1） Nitrogen fertilizer was the main source of N₂O from cropland,and the N₂O emission factor of the fertilizer application rate was between 0.1 and 2 percent. Taking the huang-huai-hai region for example, from 1990 to 2008, the rate of nitrogen fertilizer application annually increased 3.12%. The nitrogen fertilizer application rate of unit sown area reached 217.4kg N/ha, 3.3 times of the world average. But the use efficiency of nitrogen fertilizer was very low with only 30%-35%. Reduction of nitrogen fertilizer, application of slow-released fertilizer and nitrification inhibitor could effectively reduce the N₂O emissions, the mitigation potential reached 6%～30%,10%～40% and 50%～80%, respectively. It could reduce N₂O emission and increase the farmers’ income by carrying out the soil testing and fertilizer recommendation project which was economically and technologically feasible nowadays. But there were still some technological and cost obstacles in application of slow-released fertilizer and nitrification inhibitor and need more experimental and technological improvements.（2） IPCC methodology and DNDC process model were two important methods to estimate the N₂O emission from cropland. The former calculated the N₂O emissions by nitrogen input and emission factor, and the latter simulated nitrification and denitrification process in soil. Comparison with the two methods, the DNDC model reflected the spatial differences more accurately. Until now, there was no CDM methodology for N₂O emission mitigation, and hence this paper established the CDM methodology for N₂O mitigation based on the basic framework of CDM methodology. The boundary of the project included the scope of cropland applied the soil testing and formulated fertilization, and the production process of fertilizer from facility. The baseline of the project included N₂O emissions from cropland under the conventional fertilizer conditions and the CO2 emissions from production of applied fertilizers. The emission of project included the N₂O emission from the cropland under soil testing and formulated fertilization and CO2 emissions from production of applied fertilizer. In addition, the paper also defined the leak and formulated the monitoring plan.（3） Take 11 rural towns of Huantai courty as the basic unit, the N₂O emissions from cropland were estimated by using both IPCC method and DNDC model. The gross and per unit sown area emissions from cropland in Huantai County were 76.02t and 3.01kg/hm2, respectively, with 27.5% higher than the results estimated by DNDC model. Simulation results by DNDC showed that corn-wheat system was the main N₂O emissions source which accounted for 85% of total emissions, and 9.28% for vegetables, 5% for other crops. The results from DNDC model were more reasonable because it comprehensively considered the soil and climate factors.（4） Based on CDM methodologies of N₂O mitigation from cropland at county scale, project document design （PDD） on N₂O mitigation from cropland of Huantai County was carried out. The results showed that by implementing soil testing and fertilizer formulas, the greenhouse gas mitigation reached 26.5 thousand ton CO2 equivalent, amount of which the mitigation from cropland accounted for 25.3% with 9.35 thousand ton, and the mitigation from the nitrogen and phosphate fertilizer saving accounted for 58.3% and 6.8 %, respectively, with 1.54 t and 0.18t CO2 equivalent. The mitigations for each town were different due to the differences of fertilizer rates and cropland area.（5） The fertilizer application rate and the farmers’willingness of decreasing fertilizer were investigated in 7 towns, 190 households from Huantai county by using the stratified sampling method. The results showed that among the surveyed households, only 20.8% of the farmers were willing to reduce the fertilizer application rate, 76.6% of the farmers determined the fertilizer application rate by convention or seller’s recommendation, and 70.9% were ignorant about environmental pollution caused by excessive fertilization, which showed that farmers were lack of appropriate technical guidance. The influencing factors were analyzed using Logist model. The results showed that education degree,total area of cropland, cognition of excessive fertilizer, gross income and the proportion of income from cropland all greatly impacted the willingness of decreasing fertilizer rate. Scenario analysis showed that technology promotion, experimental demonstration, government subsidies and regulations, and so on, were all effective ways to promote farmers reducing fertilizer application rate.更多还原