中国山区耕地利用边际化表现及其机理
李升发,李秀彬

Economic characteristics and the mechanism of farmland marginalization in mountainous areas of China
LI Shengfa,LI Xiubin
图5 2013年中国各省玉米种植亩均用工数
Fig. 5 Per mu labor use for maize cultivation at provincial level in China in 2013