5Eagle A J, BirdJA, HorwathWRetal. Rice yield and nitrogen efficiency under alternative straw management practices [ J ]. Agron. J.,2000, 92: 1096-1103.
6Witt C, Cassman K G, Olk D C O et al. Crop rotation and residue management effects on carbon sequestration, nitrogen cycling and productivity of irrigated rice systems[J]. Plant Soil, 2000, 225: 263-278.
7Suzuki M, Kamekawa K. Effect of continuous application of organic and inorganic fertilizer for sixty years on soil fertility and rice yield in paddy field[C]. Translation of 14th Inter. Soil Sci. 1990, IV: 14-19.
8Yadav R L, Dwivedi B S, Pandey P K. Rice-wheat cropping systerns: Assessmentof sustainability under green manuring and chemical fertilizer inputs [J]. Field Crops Res., 2000, 65: 15-30.