Zhu, Z. L. and Chen D. L. (2002) Nitrogen fertilizer use in China-contributions to food production, impacts on the environment and best management strategies. Nutrient Cycling in Agroecosystems 63:117–127.
 Ju, X. T., Liu X. J., Zhang F. S. and Roelcke M. (2004) Nitrogen fertilization, soil nitrate accumulation, and policy recommendations in several agricultural regions of China, Ambio: A Journal of the Human Environment 33: 300―305.
 Khosla R., Fleming K., Delgado J. A., Shaver T. and Westfall D. (2002) Use of site specific management zones to improve nitrogen management for precision agriculture. Journal of soil water conservation 57:513–518.
 Delgado, J. A., Khosla R., Bausch W. C., Westfall D. G., and Inman D. (2005) Nitrogen fertilizer management based on site specific management zones reduce potential for nitrate leaching. Journal of soil water conservation 60:402–410.
 Li X. X., Hu C. S., Delgado J. A., Zhang Y. M., and Ouyang Z. Y. (2007) Increased nitrogen use efficiences as a key mitigation alternative to reduce nitrate leaching in north china plain. Agricultural water Management 89: 137-147.
 Zhang, Y. Zh., Wang K. R., Liu J. P., Huang Zh. N., Zeng X. and Zhou Sh. Q. (2006) Demonstrations and studies on techniques for rice quality security control. Crop Research 4: 287-296(in Chinese).
 Yao, C. X., Chen Z. L., Qiu Q., Huang Y. H., Yin J., Zhang J. X., Li C. H. and Mao G. F. (2005) Influence of nitrogen fertilizer reduction amount on watermelon yield and quality under canopy cultivation. Acta Agriculturae Boreali-Sinica 20:76-79(in Chinese).
 Jiang, Q., Yu H. J., and Shi Z. Y. (2006) Effective ways of reducing chemical N fertilizer application in rice growth. Journal of Shanghai Jiaotong University (Agricultural Science) 24: 452-455 (in Chinese).
 Parkinson, J. A. and Allen S. E. (1975) A wet oxidation process suitable for the determination of nitrogen and mineral nutrients in biological material. Communications in Soil Science and Plant Analysis 6: 1–11.
 Buresh, R., Peng S., Huang J., Yang J., Wang G., Zhong X., and Zou Y. (2004) Rice systems in China with high nitrogen inputs. In: Mosier, A.R., Syers, J.K., Freney, J.R. (Eds.), Agriculture and the Nitrogen Cycle: Assessing the Impacts of Fertilizer use on Food Production and the Environment. Washington, D.C., Island Press, pp.143―153.
 Tong, Y. N. (2001) Nitrogen fertilizer and environment. In: Feng, F. (Eds.), Study on Plant Nutrition-Progress and Prospect. Beijing: China Agricultural University Press. pp. 207-215 (in Chinese).
 Mosier, A. R. and Zhu Z. L. (2000) Changes in patterns of fertilizer nitrogen use in Asia and its consequences for N2O emissions from agricultural systems. Nutrient Cycling in Agroecosystems 57: 107-117.
 Zhang, W. L., Wu S. X., Ji H. J. andKolbe H. (2004) Estimation of agricultural non-point source pollution in China and the alleviating strategies I Estimation of agricultural non-point source pollution in China in early 21 century. Scientia Agricutura Sinica 36: 1008―1017.