Nitrogen Absorption and Utilization Characteristics of  japonica  Rice Cultivars with Different Productivities at Their Optimum Nitrogen Levels 
LI Min1,2 , ZHANG Hongcheng1,*, MA Qun1 , YANG Xiong1, LI Guoye1, WEI Haiyan1, DAI Qigen1, HUO Zhongyang1, XU Ke1
Chinese Journal of Rice Science . 2012, (2): 197 -204 .  DOI: 10.3969/j.issn.10017216.2012.02.009