WANG Shu-tao, MEN Ming-xin, LI Xin-wang, CHEN Ying, LI Jing, XU Hao . Stability of farmland ecosystem productivity and time-series characteristics of influencing factors in Hebei Plain —A case in Xiongxian County[J]. JOURNAL OF NATURAL RESOURCES, 2009 , 24(5) : 871 -880 . DOI: 10.11849/zrzyxb.2009.05.014