2Timsina J, J. Connor. Productivity and management of rice-wheat cropping systems: issues and challenges[J]. Field Crops Research, 2001,69 : 93 - 132.
3Ladha J K, D. Dawe, H. Pathak, et al. How extensive are yield de- clines in long-term rice-wheat experiments in Asia? [ J]. Field Crops Research, 2003, 81:159 - 180.
4Cassman K G, S. Peng, D.C. Olk, et al. Opportunities for in- creased nitrogen-use effieieney from improved resource management in irrigated rice systems[ J]. Field Crops Research, 1998, 56:37 -39.
5Ladha J K, Fischer K S, Hossain M, et al. Improving the productiv- ity and sustalnability of rice-wheat systems of the Indo-Gangefie Plains: A synthesis of NARS-IRRI partnership research [ A ]. IRRI Discussion paper[ C ], 2000.
6Nambiar K K M, Abrol I P. Long-term fertilizer experiments in Indi- a: an overview [J ]. Fertilizer News, 1989,34 : 11 - 20.
7Dawe D, Dobermann A, Moya P, et al. How widespread are yield declines in long-term rice experiments in Asia[ J]. Field Crops Re- search, 2000, 66: 175-193.
8Tripathi B P, J.K. Ladha, J. Timsina, et al. Nitrogen dynamics and balance in intensified rained lowland rice-based cropping systems [J]. Soil Science Society of America Journal, 1997, 61 : 812 - 824.
9Dobermann A, Cassman K G, Mamaril C P, et al. Management of phosphorus, potassium, and sulfur in intensive irrigated lowland rice [J]. Field Crops Research, 1998, 56:113 -138.
10Cassman K G, S. Peng, D.C. Olk, et al. Opportunities for in- creased nitrogen-use efficiency from improved resource management in irrigated rice systems[J]. Field Crops Research, 1998, 56:37 - 39.
