Implications for development of grain-for-green policy based on cropland suitability evaluation in desertification-affected north China

China's grain-for-green policy of returning steep cropland into forests is one of the most important large-scale initiatives to combat land degradation in its ecologically vulnerable regions. Although many papers have emphasized the importance of the policy by regarding land slope gradient as the most important limiting factor affecting cropland suitability, relatively less attention has been paid to improving the policy by examining other limiting factors in different land use regions. Taking the desertification-affected north China as a study area, this paper divides the study area into 12 different land use regions based on the systematic data on land use at county level gathered in the 1996 land survey and referring to the updated comprehensive physical regionalization of China. The paper also focuses on zonal cropland suitability evaluation with more detailed criteria. It is found that highly and moderately suitable croplands are mainly distributed in the southeastern part of the study area with better moisture conditions, while marginally suitable cropland is mainly distributed in the northwestern part of the Loess Plateau and around the central part of the Inner Mongolia Plateau. To facilitate the grain-for-green project, we suggest that more attention should be paid to gradual conversion of cropland for food security and ecological purposes, improvement of compensatory regulation for cropland loss and regional integrated development for poverty alleviation.