8Samra J S.Bijay-Singh K K.Managing crop residues in the ricewheat system of the indo-gangetic plain[C]//Ladha J K.Improving the productivity and sustainability of rice-wheat systems:Issues and impact.Madison:ASA Spec Pub,2003:173-195.
9Jeffrey A B,van Kessel C,William R H.Nitrogen dynamics inhumic fractions under alternative straw management in temperate rice[J].Soil Sci Soc Am J,2002,66:478-488.
10Phongpan S.Phosphorus adsorption in flooded soils of the central plain[J].Thai J Agric Sci,1989,22:113-127.