| 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.
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