Effects of afforestation of abandoned farmland on soil OC concentration and stock at different stand ages (*: the difference between forest and farmland was significant at P<0.05; **: the difference was significant at P<0.01; ns: P>0.05; the error bars are standard deviation of the means).

<p>Effects of afforestation of abandoned farmland on soil OC concentration and stock at different stand ages (*: the difference between forest and farmland was significant at P<0.05; **: the difference was significant at P<0.01; ns: P>0.05; the error bars are standard deviation of the means).