『Abstract
　Estimates of non-point source (NPS) contribution to total water pollution in China range up to 81% for nitrogen and to 93% for phosphorus. We believe these values are too high, reflecting (a) misuse of estimation techniques that were developed in America under very different conditions and (b) lack of specificity on what is included as NPS. We compare primary methods used for NPS estimation in China with their use in America. Two observations are especially notable: empirical research is limited and does not provide an adequate basis for calibrating models nor for deriving export coefficients; the Chinese agricultural situation is so different than that of the United states that empirical data produced in America, as a basis for applying estimation techniques to rural NPS in China, often do not apply. We propose a set of national research and policy initiatives for future NPS research in China.

Keywords: China; Non-point source; Water pollution; Water policy; NPS assessment; Export coefficients; Water resources management』

1. Introduction
2. Methodology
3. Results and discussion
　3.1. Empirical basis for NPS assessment techniques
　3.2. Non-point source estimates
　3.3. NPS estimation techniques used in China
　　3.3.1. Total measured load in a river section minus reported point source loads
　　3.3.2. Unit load and export coefficient method
　　　3.3.2.1. Rainfall-runoff
　　　3.3.2.2. Sub-surface runoff
　　　3.3.2.3. Field architecture
　　3.3.3. Hydrograph separation method
　　3.3.4. Estimation by deterministic modelling
　　　3.3.4.1. Empirical knowledge base required for process models
　　　3.3.4.2. hydrological connectivity
　　　3.3.4.3. Calibration and validation
　　　3.3.4.4. Best management practices
　　　3.3.4.5. Artificial hydrology
　　　3.3.4.6. Point sources
　　　3.3.4.7. Irrigation
　　　3.3.4.8. Definitions
　　3.3.5. Mathematical representation
　　3.3.6. Summary
4. Research needs for agricultural non-point source studies in China
　4.1. Rainfall-runoff mechanisms
　4.2. Irrigation runoff
　4.3. Erosion and sediment-associated chemical transport
　4.4. Chemical runoff
　4.5. Atmospheric nitrogen
　4.6. NPS definition
　4.7. Rural living (villages)
　4.8. Model calibration
　4.9. Rapid assessment techniques
　4.10. Synthesis
5. Conclusions and recommendations for NPS policy development in China
　5.1. Pollution control Policy
　5.2. As a secondary policy objective
　5.3. Inter-sectoral cooperation
　5.4. Leadership of NPS work in China
　5.5. Science and Research
　5.6. Hydrological Observation System
　5.7. Best Management Practices (BMPs)
　5.8. National inventory of NPS data
　5.9. Education
　5.10. Scientific Publication and Peer Review
Acknowledgements
References