【作者】 陈勇；

【导师】 杨改河；

【作者基本信息】 西北农林科技大学 ， 作物栽培学与耕作学， 2010， 博士

【摘要】 环境是人类赖以生存和发展的基础。然而,人类活动过程中不断地产生和释放污染物进入地球环境,当污染物超过环境容量时,就会对生态系统产生损害,形成污染现象。点源污染由于有明确的排污点,排污过程简单,容易控制。农业非点源污染起源于分散、多样的地区,地理边界和发生位置难以识别和确定,随机性强、成因复杂、潜伏周期长,因而很难有效控制。本研究在对农业非点源污染的相关概念及污染的特征与途径进行明确界定与分析下,构建了农业非点源污染研究的理论方法体系,并结合具体实际,对陕西省农业非点源污染进行了研究。1.构建了农业非点源污染研究的理论方法体系。禽畜粪尿、农村生活污染等营养污染物的估算采用排污系数法,根据产生污染的动物个体数量和各污染物的排污系数估算;而化肥、农药、农膜等农资投入型的污染采用农资投入的耕地负荷来衡量;固体废弃物中,作物秸秆和农村生活垃圾分别根据经济系数和人均排放量估算其产生总量。农业非点源污染的农业生态安全评价指标体系是评价污染的重要手段,遵循其构建原则,建立指标体系并通过层次分析法,综合评价农业非点源污染的农业生态安全;农业非点源污染作为一种社会经济现象,农业经济的发展必然对环境产生重要影响,环境库兹涅茨曲线作为反映农业经济增长和环境污染之间关系的假说,在农业非点源污染研究中具有广泛的应用价值。作为非市场价值评估法的一种,意愿价值评估法在农户支付意愿和农户意识行为对农业非点源污染的影响研究中具有重要作用。2.对陕西农业非点源污染进行了定量估算与衡量。通过计算分析,2008年陕西农村生活污染物排放总量达830154.14 t,其中COD_cr的排放量710594.65 t,占85.6%,TN排放量100990.91 t,占12.17%,TP排放量18568.58 t,占2.24%。农村生活污染等标污染负荷为56.32×10⁹ m³,其中TP最多,占总等标污染负荷排放的43.42%。2008年陕西省禽畜粪尿污染物排放总量为102.00万t,其中TN、TP、COD_cr污染物分别为18.51万t、4.27万t、79.23万t。禽畜粪尿总等标污染负荷达63.42×10⁹ m³,其中TN和TP所占比例较高,分别达65.18%和28.84%。2008年全省平均化肥耕地负荷为585.84 kg/hm²,远远超过世界平均及发达国家为控制化肥污染所设定的225 kg/hm²的施用水平上限,也高于全国的平均水平（430.43 kg/hm²）,而农药施用量变化不大,2008年农药耕地负荷为3.85 kg/hm²。2008年陕西省作物秸秆产生量达2003.82万t,其中,小麦和玉米秸秆是作物秸秆的主要来源,分别占作物秸秆总产生量的43.91%和50.99%。自1990年以来,农膜施用水平不断攀升,2008年农膜耕地负荷已达到9.85 kg/hm²。2008年陕西省农村生活垃圾产生量为869.95万t,耕地负荷平均为3.06 t/hm²,农村生活垃圾产生总量主要分布在农村人口多的地区,而耕地较少、农村人口密度大的地区其耕地负荷较高。通过聚类分析法,全省11个地区可分为4类污染类型区:杨凌和汉中属于重度污染区;宝鸡、安康和商洛属于中度污染区;西安、铜川、咸阳和渭南属于化肥过量施用型的中度污染区;延安和榆林属于轻度污染区。3.建立了陕西省农业非点源污染的农业生态安全评价指标体系。并从社会经济安全、农业资源安全和资源环境安全3个层次,共选取15个指标,利用层次分析法,建立相应的评价模型,进行综合评价。结果显示,陕西省农业非点源污染的总体生态安全性介于一般和较差之间,属于中等偏低的安全水平。对农业生态安全性进行分区发现:高安全性地区包括延安和榆林;一般安全性地区包括宝鸡、铜川和渭南;较差安全性地区包括咸阳、商洛和安康;极差安全性地区包括杨凌、汉中和西安。全省11个地区农业非点源污染农业生态安全性排名由大到小的顺序为:榆林>延安>渭南>铜川>宝鸡>安康>商洛>咸阳>西安>汉中>杨凌。4.对陕西省农业经济发展和农业非点源污染之间库兹涅茨曲线验证表明,农村生活污染、农膜污染和农村生活垃圾污染与农业经济增长之间存在着倒“U”型的EKC关系,且转折点分别为313.18元、336.75元和313.50元（为消除价格变动的数据）,目前污染水平已经进入转折期,有降低的趋势。农业财政支持变量和对外开放水平变量的加入,并没有改变各污染源与农业经济增长之间的EKC关系,但城市化水平对各污染的EKC曲线有重大的影响。城乡收入差距对EKC关系的影响是复杂的,未改变生活污染和生活垃圾的EKC曲线,但改变了禽畜粪尿污染的EKC曲线。5.通过杨凌和汉中的实地调查,农户对农业非点源污染及治理现状满意度普遍较低,而对农业非点源污染排放认知度比较分散。对于农业非点源污染控制的支付意愿来说,杨凌的农户支付意愿为8.17元,高于汉中农户的支付意愿（4.26元）。农户的收入水平不同,受教育程度差异和农户对污染的感知不同可能是造成支付意愿差异的主要原因。通过相关性分析,男性的支付意愿好于女性;农户年龄越大,其支付意愿越小;农户受教育水平越高,农户收入水平越高,其支付意愿越大。6.农业非点源污染控制应从经济手段和管理手段综合进行。其中,庇古手段可以通过对市场化程度高的农业生产资料进行污染税征收,也可以对具有正外部效应的退耕还林还草、废弃物资源化、废弃物处理等工程采取补贴手段实现,而押金退款手段在治理生活垃圾方面具有较好的作用。科斯手段控制陕西农业非点源污染,主要是通过建立排污权交易市场,通过市场作用进行污染调节。排污权交易可以发生在点源污染和农业非点源污染之间,也可以发生在在农业非点源污染的内部,但是政府应当建立适合陕西省实际的排污权（排污许可）。管理手段主要通过最佳管理措施实现（BMPs）,是一种重要的非经济手段,包括工程措施体系、耕作措施和管理措施体系,其中工程措施体系可以通过梯田工程、植被过滤带工程、人工湿地系统、多水塘系统等形式实现;耕作措施可以通过少耕、免耕、缓坡地等高耕作、沟垄耕作、残茬覆盖耕作、秸秆覆盖等保护性耕作技术以及配套技术措施。管理措施可以通过综合肥力管理、病虫害综合管理、农田灌溉制度等实现全省农业非点源污染的控制。更多还原

【Abstract】 Environment is the base of survival and development depended by human being. While as, pollution is always released in global environment during the activities of mankind. Pollution is formed and ecological system is damaged when the amounts of pollutants surpass the environmental capacity. Point source pollution can be easily controlled because of definite pollution discharging pot and simply discharging process. But with scatter source, indiscernibly geographical frontier and releasing pot, strong randomicity, complicated reason of formation, and long latent period, agriculture non-point source pollution is quite difficult to control. In this study, under the definite analysis of conception, characteristics and path of agriculture non-point source pollution, theoretical and methodological systems of agriculture non-point source pollution were erected. And also, empirical studies were made for agriculture non-point source pollution in Shaanxi province based on these theories and methodologies.1. Theories and methodologies are built to research agriculture non-point source pollution. Livestock’s manure & urine pollutants and rural domestic pollutants can be computed by being based on pollutant discharging index and the number of livestock or rural population. Pollutants derived from fertilizer, pesticide or agricultural film can be assessed by their load in per capita land area. Crop residues and rural domestic rubbish, as solid wastes, can be assessed based on crop’s harvest indexes and rubbish discharging amounts per capita, respectively. Evaluating indexes system of agricultural ecological security for agriculture non-point source pollution is a very important method to assess pollution, but basic principles and suitable analyzing methods are quite important for indexes system building. As a social and economic phenomenon, development of agricultural economy must effect the environment. As a hypothesis of reflecting the relation between agricultural economic development and environmental pollution, environmental Kuznets curve have widely using value, even if there have some limitation be existed. As one of non-market valuation methods, contingent valuation method plays an important role in researching on how to effect agriculture non-point source pollution by farmer’s willingness to pay and farmer’s conscious.2. Agriculture non-point source pollutants in Shaanxi province were quantitatively computed in this study. In 2008, the total discharging amounts of rural domestic pollutants were 830154.14 t. Among these pollutants, the amounts of CODcr, TN and TP were 710594.65, 100990.91 and 18568.58 t, respectively, which were respectively 85.6%, 12.17% and 2.24% of the total rural domestic pollutants. The total equivalent pollution loads of rural domestic pollutants were 56.32×10~9 m~3, and of the TP pollutants were highest, which take up 43.42%. The discharging amounts of livestock’s manure & urine pollutants were 102.00×10~4 t, in which TN, TP and CODcr were 18.51×10~4, 4.27×10~4 and 79.23×10~4 t. The total equivalent pollution loads of livestock’s manure & urine pollutants were 63.42×10~9 m~3, in which TN and TP were very high, taken up 65.18% and 28.84%, respectively. In 2008, average loads of fertilizer were 585.84 kg/hm~2, which were much higher than world’s average level and limited input level set to control agriculture non-point source pollution by developed world, and also higher than the average level of China (430.43 kg/hm~2). The consumption of pesticide has no significant variation, and the loads of pesticide were 3.85 kg/hm~2 in 2008. Outputs of crop’s residues were 2003.82×10~4 t. Wheat’s residues and maize’s residues were the main source, which were respectively 43.91% and 50.99% of the total. Since 1990, input levels of agricultural film have kept going up, and the loads have been up to 9.85 kg/hm~2 in 2008. The outputs of rural domestic rubbish have been up to 869.95×10~4 t in 2008, and the loads were 3.06 t/hm~2. The total outputs of rural domestic rubbish mainly distributed in those regions with large rural population, but those regions with less arable lands and higher density of rural people have higher loads of rural domestic rubbish than other regions. Through methodology of clustering analysis, 4 type of pollution were divided for 11 regions in Shaanxi province: Yangling and Hanzhong belong to heavy polluting area; Baoji, Ankang and Shangluo belong to middle polluting area; Xi’an, Tongchuan, Xianyang and Weinan belong to middle polluting area with excessive fertilizer input; Yan’an and Yulin belong to slight polluting area.3. Evaluation indexes system was built to analyze agricultural ecological security of agriculture non-point source pollution in Shaanxi province. In this evaluation indexes system, there have 3 guideline level and 15 indexes included. Then comprehensive analysis was made based on analytic hierarchy process and evaluation model. The results displayed: the general ecological security level of agriculture non-point source pollution in Shaanxi province was between normal security level and low security level. Results of regional zoning of agricultural ecological security for Shaanxi province display: Yan’an and Yulin have high security; Baoji, Tongchuan and Weinan have middle security; Xianyang, Shangluo and Ankang have low security; Yangling, Hanzhong and Xi’an have very low security. The order of agricultural ecological security level for agriculture non-point source pollution in Shaanxi province is: Yulin>Yan’an>Weinan>Tongchuan>Baoji>Ankang>Shangluo>Xianyang>Xi’an>Hanzhong>Yangling.4. Through Kuznets hypothesis, Empirical study has been made to analyze the relation between agricultural economic development and agriculture non-point source pollution in Shaanxi province. There exist the inverted-U relation between rural domestic pollutants, agricultural film pollutants, rural domestic rubbish pollution and agricultural economic development. The kickpoint are at the agricultural gross output value per capita of 313.18, 336.75 and 313.50 yuan, respectiovely (without price fluctuation), and at present, pollution levels have been overpass the kickpoint and have the decreasing trends. The variables of agricultural fiscal supports and the opening levels don’t change the EKC relation between agriculture non-point source pollution and agricultural economic development. But urbanization level has great affection to EKC curve of pollutants. The affection of income gap between urban and rural region is complicated to EKC, which doesn’t change the EKC of rural domestic pollution and rural domestic rubbish, but change EKC of livestock’s manure & urine.5. Through field studying for Yangling and Hanzhong, results display: farmers have low satisfaction to the current of agriculture non-point source pollution and controlling measures or policies. And also, farmers’cognition degrees were scatter to agriculture non-point source pollution. For controlling agriculture non-point source pollution, the farmer’s willingness to pay in Yangling was 8.17 Yuan which was higher than that in Hanzhong (4.26 yuan). The difference of farmers’income level, education level and perception to pollution may be the main reasons of different willingness to pay. Correlation analysis displays: masculine willingness to pay is higher than feminine; the older the farmers are, the lower the willingness to pay is; those who have higher education level and higher income have higher willingness to pay.6. Control of agriculture non-point source pollution should be made integrated environmental economic measures and managing measures. For Pigou measures, pollutants taxes can be levied to well market-oriented agricultural production materials, and also subsidies can give to those engineering with positive externality, such as grain for green projects, project of rural waste resources utilization, treating project for rural waste. Meanwhile, deposit-refund measure can play a positive role in control rural rubbish pollution. Control agriculture non-point source in Shaanxi province with Coase measures mainly need to erect the market of tradable emissions rights, and regulate the pollutants level by market. Deal of tradable emissions rights can be executed between point source pollutants and agriculture non-point source pollutants or within agriculture non-point source pollutants. But tradable emission rights or tradable pollution permits. Managing measures, as a non-economic measure, mainly based on best management practices (BMPs). Managing measures include engineering measure system, tillage management and managing measure system. Among them, engineering measure system mainly include terrace project, vegetative filter strips project, constructed wetland project, multi-ponds system project, et al. Tillage measures mainly include some conservation tillage technologies and their supporting measures, minimum tillage, no-tillage, contour plantation in slope areas, ridge and furrow plantation, stubble mulch plantation, straw mulching, et al. Managing measures can effectively control agriculture non-point source pollution in Shaanxi province by integrated fertility management, integrated pest management and irrigation management.更多还原