Biological nitrogen fixation and nitrogen export of groundnut intercropped with rice cultivated in aerobic soil and its effect on soil nitrogen fertility Chu GuiXin; Shen QiRong; Cao JinLiu; Mao ZeSheng; Zhong ZengTao; Zhao Long Acta Pedologica Sinica 40(5): 717-723 2003 https://eurekamag.com/research/004/057/004057245.php