The issues of grain,population and resources are now becoming increasingly serious in the loess gully area in China,especially under the background of Grain for Green projection from 1999.It is important to evaluate the impacts of Grain for Green projection on the grain productivity and security in the area.In this study,the data of agricultural meteorology in Changwu county in 1993 and 2009 were used to evaluate the grain productivity potentiality.The farmland area and its geographical distribution in 1993...